Using MTS815 type programmable servo rigidity tester in high temperature sandstone plates on the conventional triaxial compression test，based on the test result analysis of the characteristics and deformation parameters and strength of the specimen failure mode as temperatures(20 ℃–150 ℃) and the angle of bedding (0°–90°)，and discusses the layered sandstone anisotropic temperature effect. The results show that：(1) With the increase of angle，elastic modulus of rock shows the trend of decrease. Poisson?s ratio，crack stress，stress and peak stress shows the trend of increase with the decrease of the first. (2) With the increase of temperature，the elastic modulus showed a trend of decrease after the first increase，Poisson?s ratio shows the trend of increase with the decrease of the first. Temperature 20 ℃–120 ℃，crack expansion and stress，stress and peak stress overall weak growth trends，significantly reduced after the temperature over 120 ℃，the temperature between 120 ℃–150 ℃ a critical temperature，makes the mechanical properties of sandstone mutation. (3) The degree of anisotropy sandstone plates belongs to low anisotropy，the anisotropy of sandstone varies little with temperature from 20 ℃ to 120 ℃，and temperature 120 ℃–150 ℃，with the increase of temperature，improve the degree of anisotropy of sandstone. (4) The failure modes of bedded sandstone are affected by temperature and angle of the common. Rock damage with temperature rise by the shear failure makes the transition to tension damage. Angle of 30°，the sample mainly occurs shear damage along the bedding plane，and the strength of the rock sample minimum angle of 30°，indicating that the sandstone angle of 30° is mechanical characteristics，strength characteristics and failure mode of the most unfavourable angle.

High temperature treatment can induce thermal damage to rock. Conventional triaxial compression tests on coarse-grained marble specimens after exposure to different high temperatures are conducted. The influence of thermal damage on porosity，P-wave velocity，and thermal micro-cracking behavior is investigated and the combined effects of thermal damage and confinement on the strength and deformation behavior are studied. A GSI-softening model，which is based on the widely used Hoek-Brown model，is also proposed to capture the strength behavior of thermally-damage rock. The main findings of this study are as follows：As the treatment temperature gradually increases，more thermally-induced micro-cracks can be observed in the specimen. The porosity increases and the P-wave velocity decreases with the increase in the treatment temperature. The ductility of the rock is enhanced as the treatment temperature increases. High temperature treatment can greatly reduce the rock strength. However，as the treatment temperature gradually increases，the strengths of rock specimen under different temperature treatments approach the same，indicating that the confinement is the main factor that controls the rock strength when the confining pressure is high. Based on test data in this study and three sets of test data from previous publications，it is found that the variation of rock strength with confining pressure for thermal damaged rock can be well captured using the proposed GSI-softening model. The variation of GSI in the model can represent the thermal damage in the rock to some extent.

In terms of the characteristic of complex fracture network and stress sensitivity for stimulated reservoir volume(SRV)-fractured horizontal wells in tight oil reservoirs，based on the effective stress principle and flowing features of stimulated areas with multi-porosity media，the fluid-solid coupling mathematical model considering the system characteristics of the matrix，natural fractures and network fractures is presented. The fully coupling numerical solution of the stress field and flow field is solved by the finite element method. The accuracy of this model is verified by comparing the existing software solution，analyzing the difference of the production performance of SRV-fractured horizontal well under the condition of the non-coupled and full-coupled model，and revealing the fluid flow characteristics and productivity influence factors of tight oil. The results show that for full-coupled model，the production rate of SRV-fractured horizontal well is large but declines quickly. There is an economically optimal reservoir fracturing parameter. And the development pattern of "well factory" involving horizontal wells with large scale SRV fracturing is more favorable for enhanced oil recovery(EOR). This study could provide a certain theoretical and technical guidance for the optimization design of horizontal wells with SRV fracturing and efficient development of tight oil reservoirs.

The fractured rock mass in cold regions is a typical discontinuous medium，whose heat-transfer characteristics have obviously anisotropy and time-variation. Based on the basic principles of heat transfer，the heat-transfer characteristics of fractured rock mass with ice-water phase change were carried out in this paper. Firstly，the thermal resistance model of single fracture under minus temperature was derived by drawing from the definition of resistance，which has considered the effect of ice-water phase change and thermal convection. Then，based on the law of energy conservation，the heat-transfer model of the representative volume element(RVE) of single fracture rock mass was developed by considering the effect of convective heat transfer on the equivalent heat-transfer property. Based on the additivity of heat-transfer，the anisotropic heat-transfer model of rock mass with several sets of fractures in cold regions was established，thus enabling the equivalent continuous treatment of heat-transfer property of fractured rock mass in cold regions. Finally，the model were verified by a rock sample with a set of horizontal fractures and a rockmass slope. The results indicate that the maximum error is less than 1.0 ℃，which means the accuracy of this model could meet the needs of the real fractured rock mass engineering in cold regions.

Understanding the evolution of shear displacement，fault thickness and friction coefficient of stick-slip cycle is of great importance to understand the whole seismic cycle. In this research，spherical soda-lime glass beads are used to investigate the stick-slip behavior of simulated fault gouge under double direct shearing. The results show that in each stick-slip event，the faults will first experience a stage of elastic loading，then transfer to inelastic loading. Finally，failure happens when the friction coefficient reaches a critical value. Velocity steps from 3 to 300 ?m/s were used in a single double shear experiment. Our data show that the rate and state friction parameter(A－B) of glass beads faults is around －0.005–－0.006，which means a velocity weakening behavior. Different humidity of 50% and 100% were used to study the humidity influence. Results show that higher humidity leads to larger friction drop and longer recurrence time. For the faults that have switched to stable sliding，experiment results show that water injection will change the sliding mode back to stick-slip motion.

To obtain the relationship between microcracks and mechanical properties，slice identification and mechanical test were carried out，in which the samples were from Bayannuorigong granite mass in Alxa pre-selected region for geological disposal of high-level nuclear waste. Firstly，the microcracks are quantified by area crack linear density. Uniaxial compression tests for standard cylindrical granite samples were conducted using electro-hydraulic servo testing machine. The mechanical parameters of granite were obtained from complete stress-strain curves under uniaxial compression. The relationship between area crack linear density and mechanical parameters was researched. The results show that there is a threshold about the effect of microcracks on granite uniaxial compressive strength and deformation modulus. When the microcrack linear density is greater than the threshold，it has a good correlation with uniaxial compressive strength and deformation modulus. Otherwise，their correlation is very poor，and the effect of microcracks linear density on the mechanical properties of rocks is not obvious.

In order to investigate systematically convection heat transfer situation between fracture surface features of deep hot dry rock in enhanced geothermal system and work fluid，convective heat transfer experiments with distilled water considering thermophysical properties variations under multi-level flow rates were conducted in single fracture of artificial rocks based on N. Barton?s JRC model and advanced 3D printing technology，which can achieve that the roughness was set regularly different directions in fracture surface of rocks. The results show that the seepage characteristics of single rock fractures emerge a linear evolution under low-level confining pressure. Osmotic pressures were positively correlated with flow rates and temperatures，and negative correlation with rock roughness. The coupling between temperature field and flow field has a great influence on the fluid outlet temperature under constant confining pressure. Increase of long side roughness will enhance heat transfer in the same roughness of short side and the gap of the heat transfer coefficient and the amplitude ratio of the adjacent rock samples in different direction roughness are different. Roughness value of fracture surface has a great effect on the heat transfer. Furthermore，the directionality of roughness changes the heat transfer intensity by controlling the seepage path and effective heat transfer area，which shows that value and anisotropy of roughness are not negligible factor in the study of rock heat transfer.

The mechanical properties of rocks in ultra-deep reservoirs are very complicated，and well collapse and high pressure of fracturing construction are often encountered in the exploration of oil and gas. In order to reveal the failure damage modes and compressive strength characteristics of sandstone with different crack angles and different filling methods under the conditions of high temperature and high pressure，RTR–1500 triaxial rock testing system was used to carry out the compressive strength test experiment of sandstone cores with different crack angles and different filling methods. The influences law of different confining pressures，temperatures，crack angles and crack filling methods on rock strength were studied in the experiment. According to the experimental results，the diagram of failure criterion of sandstone cores with different crack angles is drawn under the coupling of high temperature and high pressure. The results show that：(1) the fracture dip is the most important factor affecting the failure mode and compressive strength. The failure mode of low and high angle fracture rock samples is shear failure，and the compressive strength does not change with the change of the fracture dip. The failure mode of oblique fracture rock samples is slip along the fracture surface，and the compressive strength decreases first and then increases with the increase of the fracture dip，there is a minimum. (2) The main types of micro-cracks in rock samples are different under different filling methods，which reflects the different properties of rock when it is destroyed. (3) Increasing temperature decreases the overall strength of rock samples，and increasing confining pressure increases the strength of rock samples. Coupling of high temperature and high pressure will make the rock body more fragmented. Rock samples change from brittleness to plasticity，increasing confining pressure will inhibit the effect of fracture dip.

In order to investigate the fracturing characteristics of coal in hydraulic fracturing with supercritical CO2 and water，the TCHFSM–I large-size true triaxial fracturing seepage device was used to simulate the process of fracturing coal seam by applying triaxial stress to 100 mm×100 mm×100 mm coal samples. Based on the theoretical basis of fracturing and experimental data，the pressure-time curves，surface fractures morphology and fractures width were compared and analyzed. The results showed that，compared to water fracturing，under the same three kinds of triaxial stress conditions，supercritical CO2 initiated the fractures more easily. The initiation pressure decreased by 28.3%，28.0% and 27.4%，respectively，and the reduction gradually decreased with confining pressure increasing. Supercritical CO2 fracturing could generate obvious bedding plane fractures and bifurcation fractures，and the more those fractures were generated，the smaller the growth range of main fractures was. The supercritical CO2 penetrated easily into the original bedding plane fissures and micro-fissures or pores in coal during the fracturing process，which caused the pressure to change gradually. Moreover，the fractured coal with supercritical CO2 could not easily maintain the pressure，so that the fractures width was narrow. The fractures width of water fracturing was mainly distributed in the interval of 0.450–0.650 mm and ＞1.250 mm，while the fractures width of supercritical CO2 was concentrated in the interval of 0.050–0.250 mm. The gap between the two kinds of fractures width was approximately 3–6 times，and for some local bifurcation and bedding plane fractures，even reaching about 2 orders of magnitude.

To have some insight into the bearing mechanism of tunnel-type anchorage and figure out the mechanical response law of anchor plug and surrounding rock under engineering load，the tunnel-type anchorage laboratory model test scaled 1∶100 is carried out. In this model test，the actual loading path and mechanic characteristic are simulated with the effective simulation of all transmission components such as saddles，cable strands，steels，anchor plug and surrounding rock and so on. Then the change law of interfacial additional stress between the anchor plug and rock，deformation response of surrounding rock are analyzed to study the temporal and spatial mechanism. And the possible failure mode is also predicted by analyzing the migration rule of the peak displacement point of deep rock mass. Main conclusions are draw as follows. (1) In the total loading process，the interfacial additional stress between the anchor plug and rock performs firstly as no response(under 0 to 5 times design loads) then increase elastically (5 to 13 times design loads) and grow quickly (13 to 19 times design loads) and sharp decrease at last(21 to 23 times design loads). (2) The anchor plug squeezes the burial surrounding rock layer-by layer from back parts to front parts in the total loading process and mobilizes the surrounding rock to bear together under the engineering load from the near to the distant. (3) Under 5 times design loads，the displacements of anchor plug and surrounding rock are negligible and then they will increase linear at low speed if the engineering load is between 5 to 13 times design loads. But the displacements growth will accelerate and the displacement of anchor plug will be greater than the displacement of surrounding rock when the engineering load reaches 13 to 21 times design load. Finally the anchor plug will be pulled out because of the serious damage of surrounding rock under 23 times design load. Last but not least，the cracks occur after at the displacements accelerated growth stage. The range of reticular fracture zone is 50 centimeters above the vault of anchor plug，35 centimeters below the bottom of anchor plug，35 centimeters within the left wall and 35 centimeters within the right wall of anchor plug. And the failure mode of tunnel-type anchorage is un-symmetrical trumpet-shape speculated by the fracture zone and displacement distribution law of deep-seated rock.

To study the influence of geometrical morphology on the seepage properties of rough fracture，the three dimensional rough fracture surface is generated according to the midpoint interpolation method. A lattice Boltzmann model is proposed to simulate the seepage of rock fracture，and its validity is verified by an example. Finally，the effects of geometrical morphology on pressure drop are discussed for rock fracture with single rough surface. The results show that the distribution of average pressure drop between the adjacent nodes is similar to the fluctuation height of fracture surface along the seepage direction，the average pressure drop increases at the location where the fracture surface raises，and decreases in the sunken region. The influence of geometrical morphology on the local pressure drop is different for the position with different distances to the fracture surface，the closer to the fracture surface，the more sensitive of the geometrical morphology to the local pressure drop，especially in the area where the fracture surface fluctuates sharply. The inlet velocity also affects the average pressure drop，the larger flow velocity results in the greater resistance of the rough wall to the fluid and the corresponding energy loss，the more significant pressure drop is generated as a result. Under the laminar flow regime，the inlet velocity is approximately linear with the average pressure drop.

In numerical simulation，the multi-crack propagation and intersection mode under tensile stress are mainly studied by hypothesis. In order to explore the real mode of multi-crack propagation and intersection under tensile stress，the tensile tests of PMMA specimen with two random cracks and parallel inclined double cracks are carried out. The relationship between the contour distribution characteristics of the displacement field and the precast crack of the specimen under tensile load by digital speckle correlation method，the influence on the crack propagation and the crack intersection form when the specimen destroyed are obtained. Meanwhile，the failure process of the test model under tensile load is simulated with two different intersection mode algorithms based on the extended finite element method. The results show that the existence of precast cracks has a significant effect on the contour distribution of the displacement field under tensile load，and the contour line near the precast crack is approximately perpendicular to the precast，which has a certain influence on the crack propagation path. In the crack propagation process，the pre-crack existing in the front has an inducing effect on the growing crack，deflecting the crack propagation，and finally intersecting it. And it is found that the intersection mode determined in parameterized form based on the coordinates of crack-tip and the normalized direction vector of crack propagation is consistent with the crack intersection mode observed by the test.

By conducting uniaxial compression tests on prismatic marble specimens containing prefabricated elliptical holes，the effects of major-minor axis ratio(m) and inclination angle(?) of ellipse on the mechanical characteristics of rock were studied. Digital image correlation(DIC) was also applied to record and analyze the fracturing process and damage evolution of marble. The results show that the peak strength，elastic modulus and crack initiation stress level of specimens containing elliptical holes increase with the increase of ?，and all have different sensitivity to ? and m，in which the sensitivity of the peak strength to ? increases with the increase of m. With the increase of ?，the final failure modes of specimens containing elliptical holes can be mainly classified into splitting-shearing failure and shearing failure，while the influence of m on the crack coalescence and rock failure mode is not obvious. By observing the strain field on specimen surface，it is found that the deformation and fracture characteristics of marble before and after peak stress can be clearly characterized，where the local high strain zones are good indications of crack initiation and propagation. Based on the localization characteristics of global strain field，a method for measuring the crack initiation stress of rock with hole defects is proposed. When the crack initiation stress level reaches 39.83%–76.18%，the specimens containing elliptical holes are in the critical tensile crack initiation state.

Temperature，underground water and in situ stress are crucial environmental factors affecting rock strength and deformability during deep mining. In this study，temperature water immersion time-confining pressure coupled compression experiments of red sandstone is designed and conducted based on the orthogonal experimental principles. The effects of each influencing factor on red sandstone strength and deformability are statistically analyzed and discussed. The results indicate that the temperature，water immersion time and confining pressure have great influence on the elastic modulus，Poisson?s ratio and peak strength(significance level≥90%). The confining pressure has the most significant effects while the temperature has the least effects on these three parameters. The evolution of elastic modulus，Poisson?s ratio and peak strength under the influence of the three environmental factors is also studied. The linear correlations of those parameters with the three factors are obtained. Furthermore，based on the finite deformation theory，the mean rotation angle are employed to analyze the nonlinear deformation behavior of the test rock. The evolution of the mean rotation angle are studied and discussed. A constitutive model based on the mean rotation angle and finite deformation theory is also proposed. The comparison of model results and experimental data shows that the model proposed in this study can well describe the deformation and failure process of the red sandstone.

Based on the equivalent discrete fracture network，a 3D numerical model for fluid flow in fracture network and rock matrix is proposed. The intact porous rock is discretized by an assembly of impermeable tetrahedrons. The flow，following the Darcy law，only happens in interfaces between tetrahedrons. For accurate description of spatial structure of porous rock with complex fracture network，a mesh generation method is developed. Using randomly and uniformly distributed Delaunay tetrahedrons，the geometry of 3D fracture network and complex intersection relations between fractures is directly described. The pore space of the porous matrix is hydraulically replaced by an equivalent interface network system. In order to ensure the system having the same macroscopic permeability with the intact rock，we develop an equivalent discrete fracture network model and propose a method to make connection between the macro and micro hydraulic parameters. Fractures are also treated as interfaces like the matrix，only with a higher hydraulic conductivity，which make the solving system realizable and numerically stable. To verify the efficiency of proposed method，we perform a series of numerical studies，the numerical results agree well with analytical solutions. Finally，the proposed model is applied to study the effects of fracture permeability，size，orientation，intersection position on the macroscopic permeability of rock，and the relationship between fracture density and percolation threshold.

In order to study the strength characteristics and failure process of fractured rocks，uniaxial compression tests together with AE monitoring were conducted on granites containing a single fissure. The stress-strain data，multi-parameters of AE and video recording were used to analyze the characteristics of crack evolution and their correlations. The results show that the fissure angle has a bigger influence on crack initiation stress and failure strength. The modulus and crack initiation stress increase monotonously with . The stress-strain curves of fractured rocks rise stepwise before the peak strength，and stress drop occurs several times when is small. It?s revealed that the stress drop coincides with the deterioration of modulus，sharp bulge of AE event rate and energy rate. AE event evolution of fractured granites is divided into three stages，with the increase of ，the three-stages characteristic gradually weakens and the brittle failure increases. Moreover，the number of stress drop and AE bulges gradually decrease，but stress levels corresponding to the maximum of AE rate keep increasing. Compared with AE event，the maximum energy rate occurs closer to the peak stress，and AE energy changes more severely. The spatiotemporal evolution of AE hypocenters depicts the three-dimensional propagation region and distribution of cracks. The amplitude of hypocenters occurred at the stable growth period are small，and the number of large-amplitude hypocenters increases rapidly after the high-speed growth period，especially prior to the failure.

In view of the dynamic response characteristics of weathered red sandstone under cyclic impact，cyclic impact tests under different axial pressures and different impact loads were performed by dynamic-static coupling loading device. The effects of axial pressures and impact loads on mechanical properties and energy dissipation is analyzed. The following conclusions are drawn from the results：The peak of transmitted wave increases with the increase of the number of cyclic shocks with the same incident wave，and there is a peak point in transmission wave peak. The reflected wave has a“double peaks”，it shows two obvious peak points and one valley point. The arrival times of the two peaks and one valley are basically the same. As the average strain rate increases，the dynamic compressive strength decreases gradually when the axial pressure is constant. It is show that the weathered red sandstone has good strain rate effect. The smaller the impact load and axial pressure，the greater the energy utilization rate. On the contrary，the greater the axial pressure，the smaller the energy utilization ratio. With the increase of axial pressure，the peak value of energy utilization rate decreases gradually. The maximum value under different impact loads occur at the axial pressure of 0 MPa，and the maximum value is 24%.

In order to reveal the influence of cyclic progressive pressure on the fracturing effect of shale，the true triaxial hydraulic fracturing test of shale samples was carried out，and the rupture effects of one-time fracturing and progressive pressure fracturing were compared and analyzed. The experimental results show that：(1) Based on the comparison of fracturing pressure curve，and AE energy curve，one-time fracturing method is prone to produce a single main fracture and generate relative sample hydraulic fracture networks. Progressive fracturing method tends to create multiple fractures and complex networks. (2) Based on the analysis of the AE positioning，the one-time fracturing AE location shows a liner distribution with respect to a single fracture，and cyclic fracturing AE location presents a dense distribution which filled a larger volume of test samples. (3) Based on the comparative analysis of the morphological，quantitative and fractal dimensions of macroscopic cracks，the cyclic progressive method can significantly improve the seam network density and the permeability of test samples，hence optimizes field hydraulic fracturing methods. (4) Based on the extended finite element numerical simulation，the cyclic progressive fracturing method can produce long and devious main fractures and tend to generate more secondary fractures along the main fracture，which can increase the density of fractured seams networks and enhance the effect of volumetric fracturing.

Preconvergent deformation，convergent deformation，face extrusion displacement，radial pressure of surrounding rock and failure process of instability are analyzed under the normal load and overload，a model test of large three-dimensional geomechanics outside the pit is carried out for the pre-lining method of tunnel in soft surrounding rock. The rate of preconvergence is reduced by 20%–30%，the settlement of the vault and the horizontal convergence can be reduced by 25% and 80%，the pressure of surrounding rock in the circumference of the hole is increased by 1.1 times while the pre-lining method is used in double line railway tunnel under the geological conditions of the fully weathered granite with grade V. The longitudinal influence range of the advanced core soil is about 0.3D in condition A and 0.7D in condition B，the decline is nearly 60%. The instability process of tunnel is peeling-slip-collapse of rock mass，and the collapse is finally formed with 2 m depth of side wall，1.4 m depth of vault，1.2 m depth of excavating face. Limit displacement value of stability criterion of tunnel is recommended 157 mm of vault settlement，93 mm of horizontal convergence and 225 mm of face extrusion displacement. The research results provide a certain theoretical basis for the full-face excavation of large machinery with pre-lining according to the basic theory of ADECO-RS.

This paper aims to study dynamic responses and compare aseismic bearing capacity of herringbone micro-pile and parallel micro-pile retaining structures under EI earthquake action through large-scale shaking table tests. The objective of this research is to propose the structure which shows good aseismic bearing capacity and strong deformation resisting capability under earthquake condition. The results may be as a good reference for seismic design of slope engineering and micro-pile retaining structure. It is indicated that，under EI earthquake condition：The hillside soil pressure of two kinds of micro-pile retaining structures shows“K”shape distribution above sliding surface，and the earth pressure is the largest around sliding surface. The riverside soil pressure distribution characteristics of two kinds of micro-pile structures show different performance. In addition，the earth pressure of micro-pile under the action of bidirectional coupled earthquake is higher than that of unidirectional earthquake. At the sliding surface，the landslide thrust force of herringbone micro-pile bearing is twice to five times as strong as that of parallel micro-pile. The top beam displacement of parallel micro-pile is 2.2 cm more than that of herringbone micro-pile. Compared with parallel micro-pile，the aseismic bearing capacity and deformation resisting capability of herringbone micro-pile is stronger. Besides，there is hysteresis effect in the micro-pile peak value of seismic dynamic earth pressure，and the earth pressure near the sliding surface is undulating over whole time period of earthquake. The hysteresis effect of the earth pressure at the sliding surface is more significant than others. Lastly，the acceleration of the slope is magnified along the pile body，meanwhile the acceleration magnified effect is prominent when the earthquake action is greater，and the acceleration magnified effect reaches the peak near the slope surface.

Due to the insufficiency of historical slope samples，there are frequently over-fitting problems when using traditional machine learning method to assess the stability of slope. Based on Bayesian network，this paper combines fuzzy theory with support vector machine to propose a new method for slope seismic instability scale assessment. The method utilizes fuzzy theory to solve the prior distribution of the Bayesian network parameter. Meanwhile，support vector machine is applied to solve the actual sample potential distribution of the Bayesian network parameter. Then Bayesian estimation method is used to combine the prior distribution with the actual sample potential distribution to obtain the Bayesian network of slope instability scale. This Bayesian network satisfies both the basic law and the sample nonlinearity and randomness. Using the established Bayesian network to evaluate the instability scale of 32 actual slope samples，the correct rate is 81.25%. By comparing with Bayesian network based on prior knowledge and support vector machine based on actual sample，it can be seen that the proposed method solves the over-fitting problem caused by insufficiency of samples，and the accuracy is greatly improved. Moreover，this method can also effectively assess the instability scale when the slope properties are incomplete.

With regard to a KBS-3v schemed geological repository for disposal of high level nuclear waste，a canister distributed line heat source analytical model(model I) is developed for the prediction to the 3D transient temperature field，and sample calculation analyses are conducted. The objectives are to compare with three other analytical models in the literature，i.e. the canister distributed point heat source analytical model(model II)，the drift distributed line heat source analytical model(model III)，and the zone areal heat source analytical model (model IV)，and to analyze the spatial distribution patterns and temporal variation features of the temperature field，and to study the influences of the spacing of the waste canisters on the temperature rise of the bentonite backfill. The calculations indicate：for the surrounding rocks，there are some differences in the vicinity of the canisters between the temperature solutions from model I and the three other analytical models，but with the increase of distances from the canisters and the attenuation of heat power of the canisters，such differences of temperature solution from the four different analytical models tend to diminish correspondingly；for the bentonite backfill，the peak temperature increment from model I is 27% smaller than model II，7% larger than model III，16% larger than model IV；according to model I，the temperature in the vicinity of the canisters increases drastically within the initial 100 years，and exceeds over 30 degrees Celsius based on the virgin rock temperature during 100th to 700th year，but later decreases as the heat power of the canisters attenuates; both the temperature and its rate of variation in the bentonite backfill increase if the spacing between the canisters is reduced，and so does the sensitivity. Model I is geometrically more consistent with reality，thus the calculation results are more rational，than the other three existing models.

Rock-like specimens with different angles of pre-existing cracks，made by embedded thin sheet method，were using to study the fracturing behaviors and mechanical properties of hydro-mechanical coupled cracks. In this study，1，3 and 5 MPa water pressure were applied inside the pre-existing crack respectively and led to the specimen failure with external compression loading under 6 MPa confining pressure. By analyzing the mechanical properties and failure patterns，the test showed that the failure mode changes from ductile failure to brittle failure with the increase of water pressure. The triaxial strength，post-peak residual strength and elastic modulus all decrease when water pressure increases，and decreases firstly and then increases when pre-existing crack?s angle increases. The fracture angles of intact specimens increases with water pressure increases and the failure pattern transforms from shear failure to splitting failure. When the angle of the pre-existing crack is small，the failure mode of cracked specimen affected by water pressure，and X-shaped crack morphology was observed under high water pressure. When the angle of the pre-existing crack between 60°and 90°，the fracture surface presents a single inclined plane，and the angle of the fracture surface is basically identical with the pre-existing crack.

After the drilling fluid stops circulating，the bottom hole temperature rises again，which is very easy to cause delayed damage of the wellbore rock caused by the temperature rise. The wellbore instability caused by the change of wellbore temperature during drilling fluid circulation was analyzed. Firstly，the influence of time and engineering parameters on the temperature distribution of wellbore was studied by numerical calculation method based on unsteady temperature distribution. In addition，the strength experiments of fine sandstone at different temperatures were carried out by means of high temperature and high pressure rock mechanics testing machine，and the influence law of temperature change on rock strength was researched. The experimental results show that after drilling fluid circulation，the temperature near the wellhead increases with time，and the temperature near the bottom of the well decreases with time，and there exists a critical well depth related to time. The temperature changes mainly concentrate in a small area near the wellbore，and the temperature decreases rapidly in the initial stage of drilling fluid circulation；the larger the displacement，viscosity and density of drilling fluid，the greater the decrease of wellbore temperature near the bottom hole，and the change of displacement has the most obvious effect on the temperature distribution of wellbore；the temperature increases，which aggravates the damage degree of fractured rock samples and eliminates slip damage. With the occurrence of cross-section failure and end-face failure，in the fracture dip-compressive strength diagram，the influence of temperature rise on the slip area is not obvious；with the increase of temperature，the compressive strength of rock sample decreases obviously，and the stress-strain curve becomes tortuous，there are obvious plastic deformation sections，and the failure process becomes complex.

To study the influence of smooth and rough joint on stress wave propagation in rock mass and the mechanical properties of jointed rocks，experimental research was carried out by using split Hopkinson pressure bar(SHPB) system. The effect of joint matching degree coefficient(JMDC) on the stress wave propagation was qualitatively studied. The projection covering method was used to analyze the joint surface，and the influence of fractal dimension on stress wave propagation was studied. Rough joint surface specimens were obtained from the splitting test，and two standard specimens were combined to obtain the smooth joint surface specimens. To get the same incident stress pulse，a series of SHPB experiments were conducted on the rock specimens with smooth joint and rough joint. It was shown that the transmission coefficients and stiffness of smooth joints rock specimen reduce 2.1% compared with intact rock specimen，the smooth joints have little influence on stress wave propagation in the test. The transmission coefficient and stiffness of joint rock specimens were influenced by the difference of joint forms. The greater the joint roughness(the fractal dimension is 2.088–2.214)，the smaller the transmission coefficient and stiffness of the rock joint specimen，where the equivalent stiffness is approximately linearly reduced and the transmission coefficient is reduced by a quadratic curve. When joint roughness(fractal dimension) were the same，the smaller the JMDC，the smaller the transmission coefficient and the equivalent stiffness，which indicates that JMDC is an important influencing factor of the stress wave propagation.

The cylindrical wave is one of the common wave types in rock mass blasting engineering and the cylindrical wave propagation is a great concern of rock mass excavation and underground structure safety. This paper presents a numerical study on cylindrical P-wave propagation across a jointed rock mass using UDEC. Firstly，a semicircular cylindrical cavity is established at the bottom of the model to simulate the cylindrical wave loading. Then，studies on cylindrical wave propagation across a rock mass without joint and with a single joint are conducted respectively. By compared with the theoretical results，UDEC is proved to be efficient to simulate cylindrical wave propagation across jointed rock mass. After that，parametric studies are carried out to investigate the influence of joint stiffness，the frequency of incident wave and the position of monitoring point on the transmission and reflection coefficients. The results show that the position of the monitoring point affects the transmission and reflection coefficients by influencing the geometric attenuation of the wave and changing the incident angle of the incident wave. Joint stiffness has a significant influence on the reflection coefficient within a certain range. The analysis of frequency effect verifies the characteristics of joint to filter high frequency waves. Finally，the character of cylindrical wave propagation across a set of joints is investigated. The results show that the transmission effect of the wave is corporately influenced by the joint spacing and the number of joints.

Based on the blockiness index，this study attempts to unravel the correlation of the geometrical and mechanical size effects of fractured rock masses from the perspective of the spatial structures of rock masses. First of all，a total of 35 types of multi-scale three-dimensional fracture networks of rock masses，possessing various combinations of different persistence and spacing of discontinuities，were established by GeneralBlock. Using the improved blockiness evaluation method developed by the authors，the blockiness values of the rock masses with different scales were measured，and the geometrical representative element volumes of rock masses(i.e.，geometrical REV) were obtained. Then，multi-scale discrete fractures networks of rock masses were built by the combined use of GeneralBlock and 3DEC，the change law of the rock mass compressive strength and elasticity modulus with rock mass sizes was discussed，and the mechanical representative element volumes(i.e.，mechanical REV) were determined. Finally，the geometrical and mechanical REVs were compared，and then the correlation of the geometrical and mechanical size effects of fractured rock masses was evaluated. The results show that the geometrical REV is lesser than the mechanical REV，and the mechanical size effect is induced by the geometrical size effect；with the increase in the scales of rock masses，the geometrical parameters tend to be stable，and then the mechanical parameters are the same(i.e.，the geometrical REV is achieved earlier than the mechanical REV).

Translational landslide is a unique in the types of landslide that very often produces devastating consequences as its concealment. Latest studies and surveys results showed us the cause of Zhuozishi landslide in Kaixian，Chongqing City. We in this respect have built a new model for the translation landslide and have modified the formula previously used for stability measurement. The theoretical and experimental application of the model showed that the sliding force and the anti-sliding force of the landslide have been increased by the layered sedimentation of the soft and hard inter-phase rock bed. This resulted in the translational landslide in respect to lower water level or even lighter rainfall. The possibility of average error of the conventional stability coefficient is ranged up to 32.27% due to the stepped/layered formation of the bed rock. The new and modified formula is more objective in respect of considering the role of staircase subsidence. During the evaluation regarding the safety of Zhuozishi landslide，the coefficient of stability which was based on the new modified formula was reduced to 1.031 from 1.179 which is reliable and very much consistent with the actual and concrete observation results. It was find out through the result that the stepped settlement caused an increased sliding force which can be termed as the key factor in the assessment and evaluation of stability of translational landslide. It is therefore，suggested that for ensuring the accuracy of the safety assessment and evaluation of the translational landslide on the soft-hard interlaced rock strata，the variation and difference between the sliding and anti-sliding forces，primarily caused by stepped and layered subsidence，must be taken into consideration.

Blocking degree is one of the important features when open type check dam intercepts debris flow，which determines the debris flow control benefits of check dam. So far，the design of grid-type dam trapping viscous debris flow is still in the experience stage，and there are few research on blocking type and blocking criterion. There is no theoretical basis and technical index，which urgently needs to be solved for debris flow preventing engineering design. Through the flume experiment and theoretical analysis，we study the blocking process and blocking recognition of viscous debris flow by a grid-type dam. The degree of blocking was affected by bulk density of debris flow，grid size of dam and flume slope. There are three kinds of blocked types of grid-type dam for viscous debris flow，which are total-blocked type，part-blocked type and opening type. In this study，a critical comprehensive criterion (F) of blocking performance of grid-type dam is proposed. Experimental results show that when F≤0.99，the type of blocking is total-blocked type；when 0.99＜F＜2.92，the type of blocking is part-blocked type；when F≥2.92，the type of blocking is opening type. Finally，based on the experimental data，this paper presents the empirical formula for the quantitative calculation of the blocking degree of grid-type dam，which can be used to recognize blocking degree of grid-type dam and design of grid size of grid-type dam. And the practical value of the empirical formula is illustrated，which can provide the technical support for practical engineering applications further.

In view of the shortcomings of traditional grouting materials and the current status that the coal dust is difficult to deal with in coal mine，the coal dust/polymer composite grouting material was developed in this study，which used the coal dust generated in process of underground drilling construction as filler，and supplemented by the bonding agent and some other additives. The performance of composite material were researched both in macroscopic mechanical properties and microstructural observation，the results show that there exists a suitable additive amount of coal dust in the composite material，too little amount of coal dust will limited the improvement of the composites strength，while too much will lead to the reduce in interfacial binding capacity between coal dust and resin matrix to form the internal defects in the material，and leading to an early damage and failure of the composites. The FTIR results also indicate that the reactions of hydrogen bond coating and the chemical grafting were happened inside the material. Thus，the surfaces of the coal dust were covered firmly by the resin matrix. By considering the cost of the composite material，the additive amounts of coal dust should be controlled at 30%，thus the composites has better mechanical properties and a good engineering application prospects.

In order to ensure the construction safety of the 38.5 m deep excavation for the gravity anchorage foundation of Fuma Yangtze River Bridge，an intelligent feedback analysis was applied to this excavation project. First，a three-dimensional numerical model that simulating the construction process of the excavation was built，and the deformations of the supporting structures were calculated by the finite difference program FLAC3D. Then，the non-linear mapping relationship between the geomechanical parameters and the excavation-induced displacements was established by the back-propagation neural network(BPNN). Last，the geomechanical parameters were optimized intelligently by the genetic algorithm(GA) based on the developed BPNN model and the measured displacements，and the deformations during the subsequent excavation stages were predicted based on the back-calculated parameters. The research results showed that：the back-calculated values of E1，μ1，c1，and φ1 of the completely weathered stratum，and E2 of the heavily weathered stratum were greater than the initial values，while the inversion value of E3 of the moderately weathered stratum was smaller than the initial value. The magnitudes and the variation tendencies of the predicted displacements were in good accordance with the measured displacements. At the end of the excavation，the retaining piles and the top beams had a maximum displacement of 15–20 mm，exhibiting a quite small magnitude as comparing with other case histories. Local concentration of shear stress mainly occurred at the soil-pile interface and at the toe of the excavation slope，and the plastic zones mainly appeared in the completely weathered stratum. After the completion of the excavation，there were no yielding elements in the model，and the convergence of the numerical computation was achieved，indicating the excavation was in a stable state. This study lays the basis for the subsequent construction and operation of the bridge，and offers a significant reference for the feedback analysis of similar anchorage excavation projects.

In the complex geological circumstance，prestressed anchors were prone to corrosion，which resulted in properties degradation or even failure. However，it was hard to know the health statue of the anchors accurately due to the high embedment depth and concealment. An in-situ anchor excavated experiment at Shaping II hydropower station was conducted. According to the health assessment system of prestressed anchors，the environmental index，corrosion status，chemical and mechanical properties changes，deformable features and operating time were investigated synthetically. Chemical and mechanical tests were used to evaluate the health statue of the anchors in both macro and micro perspectives. The results show that the different parts of the anchors are in different corrosion degrees because of the varied corrosion prevention measures. The prevention methods of the free and fixed part of the anchors are better than the one of the anchor head. The study results also indicate that the undamaged cement grout has positive effects on anchoring and steel strand corrosion prevention. It can be concluded that the anchors from the experiment are in good working condition，and there are no noticeable chemical and mechanical properties changes that are detected in the tests. The research methods and results could be used as reference for health assessment of similar prestressed anchors.

In case of thick and hard sandstone strata overlay on the high-gassy coal seam，sometimes gas in the goaf area will be ignited，even be exploded，due to the collapse of the roof. Taking the 1007 working face of the No.10 coal seam mining of Xiakuotan Coal Mine as an engineering background，based on the laboratory tests and theoretical analysis，the source of gas ignition by rock friction effects，the occurrence condition of slide and the influence of boundary support conditions and breaking stage on the failure of fracture rock formation were studied. The research results under the engineering geological conditions indicate that，the heat energy generated by the hard sandstone friction can ignite the gas. High-temperature friction surface is more likely to ignite the gas than the spark bundles and high temperature rock dust due to friction，and it is the main ignition source. During the first collapse process of the roof strata，the ratio of broken size to rock thickness(di/h) is usually larger than 2.6，and in the process of periodic collapse，the ratio of di/h is usually less than 2. The periodic failure of the top plate is more prone to slip-off than the initial breakage. The boundary support condition has a great influence on the instability of the rock strata. When the rock strata are broken，the boundary of simply support is more prone to slide and destabilization than that of the fixed support boundary. When the rock strata with a thickness greater than 11 m during the first collapse，or with a thickness of more than 4 m during the periodic collapse，at the boundary of simply support，it is able to meet the occurrence condition of the slide collapse. If the upper section adjacent to the working face has been mined out，the upper part of the stope is a danger zone for the gas ignition due to hard sandstone strata collapse. The preventive measures should be done about roof weakening and gas treatment.

Reasonable supporting design can effectively control and avoid rock burst disaster under the risk of rock burst，reduce the loss caused by rock burst，and ensure the safety of the staff and project. Different from ordinary high stress damage，rock burst has its special trigger mechanism and control strategy. In the engineering background of the world′s largest deep buried tunnel of Jinping II hydropower station，based on the complexity of trigger mechanism of different type rock burst，discussed the question of supporting unit selection. According to two prominent features of fracture and brittle-ductile-plastic conversion of deep buried marble，respectively from three aspects of damage depth and carrying ability，energy release quantity and energy absorption ability and deformation and deformation ability，the supporting ability under the condition of rock burst is estimated，and the features and functions of supporting unit are analyzed in detail. Then the suitable supporting unit selection method under the condition of rock burst is proposed. The burst damage characteristics of surrounding rock are deeply analyzed by the discontinuous mechanics method. Finally，the support optimization design method under the condition of rock burst is discuss. The relevant research results and practical experience can provide a reference for similar engineering design.

In order to describe the disturbance characteristics in the process of coal mining at depth，an expression of disturbance intensity based on mining stress is proposed. Mohr-Coulomb strain softening constitutive model is determined to describe the failure process of the coal and rock at depth. According to the actual conditions of coal mining，the numerical model under the conditions of mining protective layer and creep deformation at depth is built to analyze the evolution law of stress field and disturbance intensity of coal when the protective layer was extracted. Finally，the influence law of the disturbed stress field and creep deformation field is analyzed. The numerical results of vertical stress in coal are in good agreement with those of the in-situ test，which prove that the numerical simulation has certain rationality. The results show that：(1) the uniaxial compressive strength of coal and rock is significant difference. The stress attenuation rate of post peak is fast for high strength rock，while low strength coal shows the elastoplastic failure. (2) The disturbance factor based on the induced stress of coal mining is used to characterize the disturbance level of coal. The coal seam in the gob of the protective layer has extensive area of pressure relief range and shows the regional disturbance characteristics. The disturbance factor of local area without protective layer mining but affected by the roadways of the working is above 0.7，and shows high intensity disturbance characteristics. The mining stress disturbance factor has a positive correlation with the disturbance intensity，and the greater the disturbance factor，the stronger disturbance degree of the coal. (3) under the effect of disturbing and creep conditions，volume strain of coal under the gob of protective layer increases obviously，while undisturbed coal also increases over time due to the influence of creep deformation.

China has a rich reserve of deep coal resources，but the deformation instability of the roadway，as an important factor，restricts the efficient exploitation of the deep resources. The purpose of this paper is to study the convergence deformation and the stress distribution of the deep roadway during coal mining，and to evaluate the effect of bolt support. On the JI 14–31050 working face of the No. 12 mine of China Pingmei Shenma Group，long-term monitoring of roadway deformation and roof bolt stress is carried out by using the convergence instrument and the bolt stress gauge. The stress distribution and deformation characteristics of the whole working face during the mining process are analyzed by finite difference method. The results show that：(1) In the first stage of mining，the roof of roadway can be divided into five areas according to the stress of bolt and the convergence curve of roadway. (2) During the period of with drawl，the anchor stress curve shows the common single-peak curve，and there still exists double-peak curve，multi-peak curve and stress failure recovery curve. (3) By comparing the bolt preload and peak tension，the range of reasonable pre-tightening force is 50–70 kN. The research results of this paper have reference value for the support design of the tunnel in the kilometer deep mine.

A novel methodology is proposed to determine the timing of initial support installation via the numerical simulation by FLAC3D. The point safety factor is introduced to evaluate the stability of each rock zone on the excavation boundary. And the geometric mean of all point safety factors is defined as the global safety factor to evaluate the overall stability，which avoids selecting limited and specific monitoring points. Then，the comprehensive graphic relationship between global safety factor and distance to tunnel face is established. Once global safety factor decreases to an admissible value，the stability of surrounding rock is in critical state and the corresponding distance in graphic relationship is the recommended location for installing initial support. In these procedures，the installation time of initial support at the typical tunnel section can be quickly designed and fed back during construction，which is efficient and effective. Meanwhile，several cases with different conditions have been carried out to validate the regularity of the method.

Rockburst cases of tunnel engineering show that the type and stiffness of initial support system affect the characteristics，mechanism and stage development of fracture and microseismic activities of surrounding rock mass，which is a topic less discussed and needs to be fully revealed. Based on the rockburst phenomena and microseismic monitoring results of tectonic granulite section in the Micang mountain tunnel of Bazhong-Shanxi expressway，the evaluation method of composite stiffness by surrounding rock and support structures is proposed and the influence of support structure stiffness on the rockburst characteristics is explored based on the microseismic parameters. The evolution of rockburst characteristics with the stiffness condition changing from weak to strong is revealed as follows：(1) At the development stage of rockburst，a more rigid constraint condition is applied on the unloading boundary of surrounding rock，and the fracturing activity of surrounding rock tends to the effect of energy accumulating and energy transferring. The development period of rockburst is prolonged and the type and specific gravity of microseismic events are changing. (2) At the occurrence stage of rockburst，the fracturing activity of surrounding rock tends to produce higher energy release，and the field rockburst hazard show the characteristics of wider affected range by high energy shock. Microseismic events occur rapidly in a short time，and the event rate and energy rate are greatly increased. Finally，the research results can help to understand the characteristics，mechanism and development stages of rock fractures under the influence of support system，and to consider the influence of supporting system on the early warning criterion of surrounding rock failure. It hopes to provides practical data and theoretical reference for scientific and reasonable support ways to curb the risk of rockburst.

In order to study the non-linear deformation features of bedrock of nuclear power project and its effect on determination of deformation parameters，the indoor uniaxial compression test of large block from a nuclear power project was done under fine control，and the nonlinearity of its deformation features were revealed. The six different methods of getting deformation parameters of bedrock were contrasted，the results revealed that the deformation parameters got by standard indoor compression test and borehole elastic modulus test will be higher because of the higher test stress level. The deformation parameters got by acoustic wave velocity analogy method or rock mass quality classification estimation method are matched with actual stress level in water-power engineering，which will occur error when directly used in nuclear power plants engineering. The in-situ plate load test and back-analyzing method based on monitoring datum are closer to the real value when getting deformation parameters of bedrock of nuclear power plants. It?s suggested that indoor compression test and borehole elastic modulus test should be improved，and the information database including in-situ test，detection and monitor should be formed in the nuclear power project. It is also necessary to refine the in-situ test and the monitoring work when facing with important project or complex foundation and attach importance to the limitation of the test stress level when drawing specifications for the nuclear power industry.

The columnar jointed basalt at Baihetan Hydropower Station is widely distributed，with joints and cracks largely developed. In this case，the control of blasting damage has become one of the critical technical problems in the excavation of Baihetan dam foundation. Based on the excavation of protective layer of dam foundation at Baihetan Hydropower Station，we conducted in-situ blasting tests with horizontal presplitting blasting，horizontal smooth blasting and energy-relief blasting with vertical holes. By comparing the acoustic velocity of rock mass before and after each blasting tests，and the vibration test results from embedded velocity sensors in the rock mass of dam foundation，we established a relationship between the damage degree of rock mass and the peak particle velocity，and proposed a safety thresholds of peak particle velocity associated with the reduction rate of acoustic velocity. The test results showed that the safety threshold of particle peak velocity is the intrinsic property of rock mass，which is not affected by the blasting method and parameters. Under the condition of 5%，10% and 15% reduction rate of acoustic velocity，the corresponding safety threshold of peak particle velocity can be roughly determined to be 50 cm/s，65 cm/s and 90 cm/s.

Natural dams formed by landslides may produce disastrous floods after dam outburst. However，the breaching characteristics of natural dams influenced by bed slopes are still unclear. In this paper，a series of laboratory tests including seven different flume bed slope angles(1°，2°，3°，7°，9°，11°，and 13°)are conducted. The results show that three stages are observed during dam breaching. In stageⅠ，the breach develops slowly. And，flow break point is occurred on downstream slope. In stageⅡ，the breach develops quickly in depth and width due to backward erosion. The shape of the breach is similar to trapezoid during this period. In stage Ⅲ，the flow water and sediment turns to a new balance. There is a non-monotonic relationship between peak discharge and channel bed slope. With increasing of channel bed slope，peak discharge increases firstly and then decreases. The backward erosion is the main driving force to deepen the breach when slope angle is small. However，the development of the breach could be seriously influenced by traction erosion when slope angle is large. When channel bed slope is below 3°，the ratio of breach width to depth increases as the channel bed slope increasing. Otherwise，the ratio of breaching width to depth decreases with the same tendency. The ratio of breach width to depth after dam failure tends to be 1 and then less than 1 with the slope increasing.

Kinetic energy and its variation rate were used as early-warning indictors based on deep displacements. On the basis of deep displacement data obtained from a large number of landslides，the characteristics and variation laws of accumulated displacement vs. depth curves，displacement rates at different depths，kinetic energy and its variation rate were analyzed in the processes of landslide evolution，the methods applied to distinguish the different deformation stages were established. The results demonstrate that the values of the displacement rate above sliding surface are different，but the variation laws with time are consistent on the whole. During the processes of landslides enter into accelerative deformation stage from constant deformation stage，the variation rate of kinetic energy increases from zero to a larger positive value. The kinetic energy and its variation rate increase sharply and show significantly catastrophic characteristics at the stage of critical sliding. The early-warning indictors of kinetic energy and its variation rate established in this paper are able to distinguish the deformation stages of landslides finely and decrease misjudgement rate caused by external factors frequently such as rainfall，artificial activities etc. The characteristics of early-warning indictors based on deep displacements can be used to distinguish different deformation stages of creep landslides better.

Red-bed soft rocks with gentle dip angle，which comprise sandstone，mudstone and shale，are widely distributed in Wumeng Mountain Area，and numerous landslides are easily triggered by soft and hard interbedded rocks. In this study，Huashengdi landslide was studied using geological investigation and centrifuge tests，which aimed to explore geological evolution and sliding process affected by rainfall infiltration. According to the study results，red-bed soft rocks have geomechanics properties of easy softening，creeping，weathering and disintegration. The interaction of rock damages and water softening，which has been found to be the main factor for affecting the stability of red-bed soft rock slope，where deep cracks are formed by geological action，such as earthquake，valley incision，etc. Meanwhile，the cracks promote the rainfall infiltration，resulting in saturated water softening at the sliding zone，quick creep deformation and even sliding. It may eventually give rise to the damage due to hydrodynamic instability in heavy rains. Geological evolution and sliding processes of landslide are divided into four stages，including the initial status，damage and degradation of rock mass，water softening and creepage，and instability triggered by rainfalls. The study results serve as the basis for analyzing the stability mechanism and engineering improvement of rainfall-type red-bed soft rock slopes.

There is a close relationship between the fractal dimension based on fractal theory and the law of rock mass failure activity. In order to study the variation law of space-time fractal dimension of rock mass failure，reveal the essence of rock mass failure and achieve the purpose of forecasting，this paper uses box dimension calculation method to analyze the source location data of the Ashele copper mine microseismic monitoring system and the relationship between its spatial-temporal distribution law and production activities，development projects，etc. Firstly，there is a significant correlation between the temporal and spatial distribution characteristics of the source location and the fractal dimension. Secondly，when the sphere coverage which radius is 5，the time-space fractal dimension and the no-scale interval fit optimally. That is to say，according to the fractal dimension，Predicting the prediction of rock failure process is the most accurate. Finally，changes of the time and space fractal dimension which are closely related to the energy release have the same trend，which is more conducive to practical engineering applications.

The under-ground oil storage has been developing in China recently. Because of the specificity of under sea oil storage，the conditions of grouting material was more strict than other projects. The material must have good fluidity，high initial strength，and stable high strength in long term. Aims at the specific conditions of under sea storage grouting material，sulphoaluminate cement was selected as grouting basic material in this experiment，and different admixtures were selected to test the adaptation with cement. It was found that the fluidity was lower when mixed with sea water compared with fresh water；boric acid can adjust the initial and final set time with a good linearity；the strength of the cement was guaranteed by mixing F10 water reducer but the UNF–5 made it fluctuant. Therefore，the grouting material of under sea oil storage was mixed out which was satisfied with the constraint conditions.

The size effect is an important factor affecting the uniaxial compressive strength，forms of deformation and damage evolution of cemented backfill. Based on this，using WAW–300 micro-electro-hydraulic servo universal testing machine，acoustic emission and ultrasonic monitoring system，three different sizes of square samples with side length of 50，70 and 100 mm were selected for uniaxial compression test. The variation rules of acoustic emission parameters and ultrasonic velocity were used to investigate the damage evolution law of cemented backfills with different sizes. The research results show that：(1) With the increase of size，the uniaxial compressive strength of cemented backfill shows a trend of increasing first and then decreasing，and the failure form changes from mainly splitting failure to shear failure. (2) The variation rules of acoustic emission parameters and ultrasonic velocity show obviously multistage and volatility：with the increase of size，the accumulative counting curve of acoustic emission ringing tends to be gentle during the quiet period，but the increase rate is higher during the active period；and the ultrasonic wave velocity increases during the quiet period and the active period. (3) The dissipated energy in the damage evolution of cemented backfill is the internal factor which affects its compressive strength，when the damage degree in the post-peak failure process is the main reason which affects its failure form. The research results can provide guidance for the prediction of fractures of different sizes of cemented backfill.

Microseismic signals are often highly corrupted by unwanted noise in engineering. The performance of existing denoising methods depends on the accuracy of selected parameters that need to tune manually. Thus，we have proposed a non-parametric automatic denoising algorithm for microseismic data，named PD method. In this method，we use a modified AIC(akaike information criterion) algorithm to obtain the background noise of the signal，then the noise power spectrum is extracted by Fourier transform in the frequency domain. Next，the noise power spectrum is subtracted from the signal power spectrum，and then we can recover the microseismic signal by inverse Fourier transform. We have tested PD method by synthesized signals with different types and different signal-to-noise ratios using Matlab and compared the result with EEMD and wavelet denoising method. Results show that the mean absolute error and standard deviation of the denoised waveform after PD method are better than that after EEMD and wavelet denoising. For signals with low signal-to-noise ratios，PD method still has a good performance. We have denoised 2 730 microseismic signals recorded by a microseismic monitoring system in Qinling No.4 inclined shaft of Shaanxi Yinhanjiwei project，China. The average P-wave signal-to-noise ratio is increased from 16.49 to 35.62 after PD method denoising. The results show the effectiveness of the proposed method for improving microseismic data quality.

In the process of deep coal mining，the rock is affected by high in-situ stress and strong mining disturbance，which is a typical dynamic and static combined loading problem. However，few mature projects can be used for reference in the exploitation of thousand meters mines. A series of geological disasters derived from underground mines directly affect the mining safety. In order to explore the rock pressure behavior law and overburden displacement characteristics of mining face at thousand meters mines，a three-dimensional monitoring system of rock pressure and overburden separation displacement was established，which was based on 24130 mining face of No.10 Mine in Pingdingshan. Under mining conditions，long-term monitoring and data analysis were carried out for borehole stress，bolt stress and roof separation displacement in the process of protective layer mining. The results show that the influence of mining disturbance on deep rock presents remarkable non-linear mechanical characteristics，not single linear increase or decrease. Moreover，the mining disturbance does not have a significant impact on the rock pressure behavior in the whole mining process，but has a significant impact in the ranges of 45–65 m and within 25 m from the mining face. The disturbance effect is remarkable with the increase of mining speed in the above two ranges. Therefore，reducing the mining speed to about 0.5 m/d in the fractured area can ensure the integrity of rock structure and the surrounding rock can have certain bearing capacity. In addition，the influence of mining on roadway roof is more significant than that of roadway sides，and the roadway roof should be strengthened in support design. The main influence area of mining on overburden displacement is in the range of 15–5 m in front of mining face. In this area，roof separation displacement develops faster，and the development speed of roof separation displacement is more significantly affected by the mining speed. It shows that when the mining speed is controlled appropriately in the range from 0.8 to 1.1 m/d，the production requirements can be guaranteed and the roof management in front of the working face can be more conducive，which provides scientific guidance for the safety production of thousand meters mines.

According to the equivalent stiffness method of elastic theory，pipe-roofs can be regarded as stiffening rib and reinforced rock can be regarded as an isotropic plate. The reinforced rock and pipe-roofs can be considered as an anisotropic plate on elastic foundation with specific constraints on the four edges. The model of anisotropic plate on elastic foundation is established and solved by finite element method-COMSOL PDE. The mechanic behaviors of pipe-roofs are analyzed. The supporting effects of two commonly used types of pipe-roofs(?76 mm and ?108 mm) are compared and analyzed based on the model tests? result. The research shows that：(1) the stress and deformation of the grouting stabilization area mainly appear in the section no more than 6m ahead of the working face. After adjusting ?76 mm pipe-roof to ?108 mm pipe-roof，My and Mx increase by 56.9% and 5.5% respectively，while the maximum deflection decreases by 38%. It shows that the greater the stiffness of pipe-roof support，the more upper load it needs to bear. So the deformation of surrounding rock can be effectively controlled by reducing the relaxation deformation and stress release of the upper surrounding rock. My of ?108 mm and ?76 mm pipe-roof are 13 and 20 times the size of Mx respectively，which indicates that the pipe-roof has obvious effect on My along the tunnel. But the Mx can not be neglected. Model tests show that a bearing arch is formed with the pipe-roof and the surrounding rock to bear the upper load during the tunnel?s excavation. Along the longitudinal direction of the tunnel，the pipe-roof plays a role of supporting beam to reduce the rock mass?s deformation and the stress release and improve the stabilization of the working face.The achievements are successfully applied in the shallow buried tunnel?s construction. The tunnel?s section is large，and the surrounding rock mass is very weak，and an existing highway project stands nearly. After adjusting ?76 mm pipe-roof scheme to ?108 mm pipe-roof scheme，the maximum surface settlement monitored in the field decreased by 38% and that of the indoor test decreased by 37%. The engineering application shows that the tunnel?s construction is safe and the achievements are reasonable.

In cold regions，the moisture，temperature and deformation of foundations is affected by freeze-thaw cycles. The cone-cylindrical pile is a kind of short expanded pile with a base，which has been widely used in permafrost regions，but its theoretical research is still lagging behind engineering practice. Through model test，temperature field，moisture field and vertical deformation of pile and soil were monitored by temperature sensors，moisture sensors and laser displacement meters, respectively. Combined with the number of freeze-thaw cycles，the dynamic variation laws of moisture，temperature and deformation were analyzed. The results show that the freezing depth of backfill increases with freeze-thaw cycles. The pile foundation is more sensitive to the ambient temperature change and thermal conductivity of pile is better than that of soil，so pile foundation can provide a good heat exchange channel between deep soil and external environment. Therefore，the temperature field distribution during the freeze-thaw cycles is closely related to the pile shape. The moisture migration is driven by temperature potential，gravity potential and capillary action，and the migrating water is blocked by frozen layer and the base of pile. The water content reduces at pile side，and accumulates at the pile bottom. The deformation of pile and soil increases with the freeze-thaw cycles. The maximum deformation of pile foundation is 8.0 mm，and the soil deformation is up to 1.9 mm. The relative deformation between pile and soil dramatically increases in the first several cycles，and then increases slowly，ultimately achieves a dynamic stable deformation stage.

A soil stabilization method using modified carboxymethyl cellulose(M-CMC) is developed to control soil loss of slope in seasonal frozen region. A series of laboratory experiments is conducted to study the effect of the number of freeze and thaw cycles and freezing temperatures on the shear strength，infiltration coefficient，structure and durability of stabilized loess and fine silty sand. Results show that the volume and infiltration coefficient of stabilized soil increase with the increasing of number of freeze and thaw cycles，but shear strength decreases. Volume，shear strength and durability decrease with the decreasing of frozen temperature，but infiltration coefficient increases. The volume and infiltration coefficient of stabilized loess changes more significantly compared to that of stabilized fine silty sand experiencing to frozen action. Meanwhile，the internal friction stress of silty sand changes more significantly compared to loess as the cementation of sand is weak. The durability both two stabilized soil shows similar trend. The coated cementation and adsorption between M-CMC and soil particles make a steady structure to increase water binding capacity. Hence，water content of soil specimens increases subjecting to frost heaving and thawing process. The higher sample?s water content is，the more serious plastic deformation and damage between aggregates is. This is the main reason why plastic deformation and even crack are generated for aggregate. Then the structure of stabilized soil is damaged and the properties of soil are affected. However，frost heaving damage from frozen are released and the durability of stabilized soil was held under the elastic connection between M-CMC and particles.

Using 3D discrete element method with force-line flexible boundary，principal stress axes rotation (PSAR) loading is achieved in arbitrary plane of cross-anisotropic granular matter. Volume strain is always contractive for various θ，the angle between the specimen?s bedding plane and the PSAR plane，and its relative magnitude varies under different intermediate principal stress coefficients. When θ = 0°， the fluctuation of the volume strain，the non-coaxial angle between the strain increment direction and the principal stress direction，and the coordination number of the specimen disappears，as the specimen is “inherently isotropic” in the PSAR plane. The direction of the normal strain in the PSAR plane changes for various θ. The relationship between the principal contact normal fabric orientation and the principal stress orientation is a likely explanation of the fluctuation of the macroscopic quantities，which is strongly influenced by θ.

In order to reveal the uplift bearing behaviors and load transfer mechanism of vertically loaded batter piles, 10 model tests were conducted for single batter piles embedded in dry medium dense sand. The influence of shaft inclined angle and the ratio of the pile length to shaft diameter(L/D) on the uplift bearing capacity was investigated；and the characteristics of the axial force，the bending moment，the shear force and the average skin friction on pile shaft was analyzed. The difference of the uplift bearing capacity between the batter piles and its vertical counterparts was also studied. Results indicate that the uplift bearing capacity of the batter pile is not always bigger than that of the vertical pile，which notably depends on the shaft inclined angle and the ratio of the L/D. The magnitude of the axial force in batter pile induced by uplift is greater than that in vertical pile，the bigger the inclined angle，the greater the axial force of the batter piles over that of the vertical piles. Both the bending moment and shear force caused by uplifting on the upper segment of batter piles are influenced by the inclined angle and the ratio of L/D. With the exception of a maximum shear force occurring on the pile head for batter pile，an extreme value of shear force will also be caused in the inclined shaft below the pile head. Negative skin friction exists on the upper segment while positive skin friction on the lower segment of the inclined piles.

In this paper，a two-dimensional consolidation theory for soft foundation under vacuum preloading combined with electro-osmosis was established，which considers the exponential reduction of the effective voltage with time. Then，an analytical solution for excess pore water pressure was derived，and the calculation formula for average degree of consolidation was given. The accuracy of the proposed analytical solution was evaluated by validating it against numerical solution. Assuming that the vacuum degree is linear decrease along the depth，the influences of the reduction of the effective voltage and the decreasing of the vacuum degree to the consolidation behaviour were analyzed. The results show that the slower the reduction of the effective voltage is，or the larger the residual effective voltage is，the faster the dissipation of the excess pore water pressure and the larger the value of the negative excess pore water pressure in the foundation are，but the slower the consolidation is. Besides，the larger the reduction of the vacuum degree along the vertical drain depth is，the slower the dissipation of the excess pore water pressure and the smaller the value of the maximal negative excess pore water pressure in the foundation are. However，the influence of the reduction of the vacuum degree on the consolidation degrees is little.

The yield stress and compressive index of calcareous sand under high stress conditions can be investigated by one-dimensional compression tests，but the lateral stress is difficult to be measured. This paper conducted 17 1D compression tests and 17 three-dimensional finite element numerical simulations on calcareous and silica sands. The effects of the tube roughness，thickness and lengths were analyzed. It is found that the compressive modulus of silica sand is approximately 3–4 times that of calcareous sand with an almost identical relative density. The compressive modulus increases with increasing relative density. The yield stresses of calcareous and silica sands are approximately 2 MPa and 10 MPa，respectively，beyond which amount of particles begin crush. The compression index of calcareous and silica sand is approximately 0.90 and 0.65，respectively. By comparing the computed and measured results，it is found that if the lateral stress is back-calculated by the outer tangential stress in tests，the stress state at the center of the samples is reasonable. Fulfilling the requirement in deformation，a smooth inner surface and a thin wall of the tube can efficiently decrease the monitoring error.

The state parameter can be used to effectively evaluate the relative density and liquefaction potential of the cohesionless soil. However，at present，the determination of state parameter is mainly dependent on laboratory tests，and it is difficult to reflect the real state of the field. The seismic wave piezocone test(SCPTU) can provide in-situ parameters such as cone tip resistance，sleeve friction resistance，pore water pressure and shear wave velocity. Based on the research results of SCPTU testing to determine the state parameter and SCPTU testing data of the three sites，firstly，the different evaluation methods of state parameter are compared，secondly，the correlation between the normalized shear wave velocity(Vs1) and in-situ state parameter is established，and the contour lines of state parameter profile in the plane of the shear wave velocity and the effective vertical stress(Vs-?′v0) are drawn，thirdly，the revised model of the relationship between normalized small strain stiffness(G0/qc) and state parameter has been proposed. Finally，these proposed methods are applied to the evaluation of the density and liquefaction potential of the cohesionless soil. The results show that the two calculation methods proposed in this paper can effectively evaluate the state parameter of the cohesionless soil，and the state parameter evaluated can be effectively used for evaluating the dense state and reliably discriminating liquefaction potential.

To explore the law of dehydration-consolidation of full tailings filling slurry in the case of Electro-osmosis，the dehydration test of the full tailings with cemented and non-cemented filling slurries were conducted on the self-made electro-osmotic dehydration and natural dehydration test device. After monitoring series factors, like the height of filling slurry，temperature，drainage，electric current，anode and cathode moisture content，power consumption and testing blocks strength of the backfills，the characteristics of dehydration- consolidation in full tailings filling slurry under different conditions were compared. The following conclusions are drawn：(1) The effect of electro-osmotic dehydration is obvious under the situation of full tailings non-cemented filling slurry；(2) The effect of electro-osmotic dehydration in the filling slurry is mainly related to the physicochemical properties of the filling slurry itself；(3) The energy consumption coefficient in the process of electro-osmosis is gradually increasing. The power supply can increase the temperature and resistivity of the backfills，with the anode seriously corroded；(4) When arranging the electrodes longitudinally，it can?t be energized when the overflow water has not been drained，otherwise violent electrolysis phenomenon will be observed.

Air-boosted vacuum preloading can overcome the problem of clogging of classical vertical drains，but there is lack of theoretical basis for the consolidation of air-boosted vacuum preloading method. The analytical solution of consolidation of single-layer homogeneous soil with air-boosted vacuum preloading is proposed which is based on the assumption of equal strain of soil，Newman-Carrilo equation and the intergral-transform method. And the results were compared the analytical solution with that from the separation variable method. At last，the engineering practical charts and tables are put forward to actual reference. The results show that：With the increase of Th，the total average consolidation degree grows rapidly. With the increase of n，the consolidation rate decreases；the analytical solution obtained by integral-transform method and separation variable method have little difference，which can be used to complete the derivation of the analytical solution of air-boosted vacuum preloading consolidation.

Water and mud inrush disasters induced by filling material instability occurs frequently in karst area，in order to study the mechanism of grouting for clay filled in the karst caverns，a laboratory experiment system，consisting of pressure confining system，data acquisition system，cement grouting module and pressure chamber were designed，which could simulate the real stress condition and seepage environment. With this experiment system，grouting experiments were carried out to study the influences of clay sample density and cement pressure for the grouting process，Shear and penetration tests were implemented on soil samples before and after grouted. The test results show that：(1) the grouting form changes from compacting into fracturing with the grouting pressure surpassing the splitting pressure，which increases from 0.49 MPa to 1.22 MPa when samples? porosity decrease from 37.5% to 35.5%；(2) The grouting fracturing channels reach further and start forming fracture networks with the grouting pressure increasing constantly，and the fracturing direction is controlled by samples? stress state；(3) Strength and permeability parameters are reinforced significantly after grouting，cohesion values up by 84.26%，permeability coefficient decreases by 93.97%；(4) the grouting process also changed samples? original internal structure，which makes their shear-displacement curves acquire more strain-softening characteristics. The research results have a guiding significance for the understanding and evaluation of grouting effect for clay filled in the karst caverns.

There sometimes exits notable difference between the consolidation process of soft soil based on Terzaghi?s one-dimensional consolidation theory and the field settlement observations，which can be in a certain extent ascribed to that the theory assumes the consolidation coefficient is constant and ignores the influence of initial consolidation state and consolidation process on permeability coefficient. According to the Darcy permeability coefficient formula，Kozeny-Carman permeability coefficient formula and e-lgσ relations of three consolidation state soils，the permeability coefficient prediction formulas of soft soil in process of surcharge preloading are established considering the influence of the initial consolidation state and stress state during consolidation process. The applicability and reliability of the predictive formulas are explored by the laboratory consolidation-permeability test and reference. The prediction formulas are substituted into the consolidation coefficient expression to obtain the modified Terzaghi one-dimensional consolidation equations considering the influence of the initial consolidation state and stress state during consolidation process. And the rationality of the modified Terzaghi one-dimensional consolidation equations is discussed by engineering application analysis. The results show that the predictive formulas can quickly and accurately estimate the permeability coefficient of the soft soil in the process of surcharge preloading. When the overloading is small，the calculation results of Terzaghi one-dimensional consolidation equations and original equations are similar. However，when the overloading is large，the consolidation process has a greater impact on the porosity ratio and permeability coefficient of soil. The consolidation degree calculated by modified Terzaghi one-dimensional consolidation equations is obviously behind the pre-modified calculation result，which is greatly agree with the engineering practice. The purpose of this paper is to provide a more accurate consolidation calculation method for the soft soil of different initial consolidation state.

To mitigate the thorny problems associated with traditional Portland cement production in terms of energy consumption，CO2 emissions and air pollution，a favorable alternative option-novel and low-carbon alkali-activated industrial by-products is proposed for sludge solidification. Based on unconfined compressive strength，X-ray diffraction，scanning electron microscopy，thermogravimetric and mercury intrusion porosimetry tests，a systematical study has been performed to analyze the mechanical strength，hydration product，section morphology，thermal stability and micropore structure of alkali-activated fly ash solidified sludge and to reveal finally their strength evolution and microstructural mechanisms. The test results demonstrate that the compressive strength of dredged sludge is significantly enhanced owning to the incorporation of alkali-activated fly ash. Compared to Na2CO3，NaOH and Na2SiO3?9H2O have gained much more attention because of their excellent performance to activate the potential activity of fly ash. Through the OH－ attack to the inner and outer glass sphere structure，fly ash is effectively activated by dissolution-polymerization to form aluminosilicate polymer gels N-A-S-H with different degrees of polymerization，binding fine particles together to increase the overall strength of solidified sludge. The increase in alkali activator content leads to an elevated production amount of N-A-S-H gels，an increase in thermogravimetric weight loss and a transformation of inter-aggregate pores to inter-particle pores. The above changes produce a denser micropore structure and better integrity，which promotes significantly the strength performance of solidified sludge. The obtained results deepen the understanding of macro- and micro- characteristics of alkali-activated fly ash solidified sludge，and establish the full microscopic reaction model of alkali-activated fly ash to clarify the intrinsic micro-mechanisms for strength improvement and to provide the theoretical basis for partial replacement of Portland cement by alkali-activated fly ash in sludge solidification.

On account of the poor engineering properties of muddy soft soil with high water content，low shear strength and high content of organic matter，the laboratory studies on the properties of the organic soil solidified by the composite magnesium cement-curing agent were carried out，in which the magnesium oxysulfate cement with the good performance on energy conservation and environmental protection was chosen as the main curing agent. Firstly，the basic proportion of the soft soil solidified by the magnesium oxysulfate cement was determined through analyzing the effect of the content of organic matter and water content and dosage of magnesium oxysulfate cement on the stabilized results. Secondly，the sodium silicate，clinker，and silica fume were chosen to be the additives of the composite curing agent based on the results of double-doping experiments. Then，the central composite rotatable design(CCRD) tests with three factors and five levels were designed，in which the unconfined compressive strength of the stabilized soil at 7 d age is considered to be the evaluating criterion. Furthermore，the composite magnesium oxysulfate cement curing agent-TZ18 was developed by using the response surface methodology. Finally，through using the technology of scanning electron microscope the microstructure of the TZ18 stabilized soil was analyzed by comparison with the Portland cement and magnesium oxysulfate cement stabilized soil. It was found that at the same age，TZ18 stabilized produced more hydration products，had stronger bonds between the particles and more stable micro-structural characteristics than the other two kinds of stabilized soil.

With the widespread application of the new slope reinforcement method using soilbags，the drawbacks of extensive layout of soilbags have been gradually revealed. Therefore，it is imperative to research on the optimized application of soilbags. The pressure failure tests in seven cases changing the parameters of soilbags，including the size and form were carried out through the laboratory physical scale model test. In order to explore the reinforcement effect and its law of the width and tail length of soilbags on soil slope，the failure mode and failure pressure of each slope specimen，the vertical distribution law and horizontal transfer rule of earth pressure and the change trend of earth pressure with increasing load have been analyzed. The experimental results indicate that soilbags are effective in reinforcing soil slopes. The larger the reinforcement width of the soilbag is，the better the effect is. However，the longer tail length is not better in the case that the economic cost is constant.

Using the modified Miller Soil Box，a series of experiments for Hangzhou silty soil were conducted under three different levels of initial water content and salt content. In order to obtain the variation discipline and distribution feature of soil electro-osmotic conductivity，experiment results were interpreted from the perspectives of the overall soil conductivity as well as the regional soil conductivity. Under different initial water content，it is demonstrated that the overall soil conductivities are adjacent and decrease during electro-osmosis，meanwhile the overall soil conductivities change linearly with spot water content and the change rate decreases with increasing initial water content. Under different initial salt content，a variation of first increasing to the peak and then decreasing to the balance is observed for the overall soil conductivity. The peak value is higher and appears later with higher initial salt content while the overall soil conductivities are similar at later stages of electro-osmosis. It is also found that the inhomogeneity of the soil conductivity distribution firstly increases and then decreases during electro-osmosis and huge difference exists between the soil conductivity near the cathodic region and other regions. Under varied initial water content or salt content，the soil conductivity distributions vary at earlier stages of electro-osmosis and are similar at later stages of electro-osmosis. The obtained results can further reveal the electro-osmotic mechanism and provide references for the design and calculation methods of electro-osmotis technique.

Based on the combination of theoretical calculation and model test，the influence of two factors on longitudinal strain and pile impedance gradual change is studied considering the material damping of pile body and the generalized Voigt model of pile side soil. We found that the model test is in good agreement with the theoretical calculation. The longitudinal length size of the pile body defect will obviously affect the reflection phenomenon of the pile body defect and the varying degrees of the pile impedance will also behave regularly on the time history curve. The results obtained in this paper can provide guidance for the testing of pile integrity in practical engineering，in order to reduce the risk of misjudgment.

In this study a settlement monitoring and analysis method considering the dynamic randomness of process is established via introducing SPC(statistical process control). This method determines whether the settlement change caused by tunnel construction is under stable control using statistical control charts and whether the settlement accords with the code using process capability index. The decision is made based on these answers. The proposed method is applied to analyze the settlement of shield construction under Beijing—Tianjin intercity railway in Beijing Metro Line 8，a vital project in the traffic construction，accordingly the feasibility and advantage of this method is verified. Over traditional methods，this method has advantages as follows. First，this method can analyze the dynamic randomness of settlement change reasonably. Then，this method can analysis the characteristics of settlement change scientifically. Finally，this method can propose the measures of engineering reasonably based on analysis for data.

The combined prefabricated horizontal drains(PHDs) with vacuum preloading is an effective method to treat the dredged clayey soils and shows significant advantages in shallow licensed storage dumps especially. This paper investigated the consolidation/dewatering characteristics of dredged high-water-content clay slurry using prefabricated vertical drains(PVDs) and prefabricated horizontal drains assisted by vacuum preloading. The dewatering capacity，surface settlement，bending of drains and water content after consolidation were recorded and analyzed. Compared with PVDs，the PHDs effectively avoided bending and thus resulted in a very uniform deformation within the model ground. The thickness of soil domain above and below the PHD decreased with time which accelerated the vacuum consolidation indicated by the dewatering rate from tests. The PHD showed a better treatment than PVD，and the water content of model soil decreased from an initial value of 360% to 150% in PHD consolidation which is 30%–40% lower than PVD consolidation. The possible differences between model tests and field cases due to size effect were discussed finally.

Based on the problems existed in the complex environmental geotechnology caused by oil contaminated saline soil，lime and fly ash was chosen as solidified materials，triaxial shear strength and scanning electron microscope(SEM) experiments were carried out to analyze the requirement mechanism of solidified parameters to different oil contaminated level. Results indicated that：(1) Cohesion(c) of solidified soil was improved more remarkable than that of internal friction angle(φ). With lengthen of curing periods，soil deformation modulus and deviator stress was gradually increased，and the failure form was changed from strain hardening to strain softening. (2) Oil contamination had less effect on curing reaction as it was slight(contaminated level ≤4%)，and the suitable solidified parameters were lime of 6%+fly ash of 20%+curing period of 28 d. In addition，the c，φ were affected obviously by oil characteristics in the initial curing，and the problems of expansion and the slide action was caused by the increase of lime and fly ash content. (3) As regards oil contamination level of 4%–8%，shear strength was degraded by oil contamination，and the suitable solidified parameters were lime of 8%+fly ash of 25% +curing period of 28 d. There was dynamic variation among transition point of oil lubricity to viscosity，lime content and oil contaminated level in the initial curing. (4) For oil contamination level of 8%–12%，oil viscosity was decreased with the increasing of lime content，and then the extent and rate of pozzolanic reaction was delayed by the physical containment of oil. As an incomplete crystallization，strength was increased continually in later curing. Therefore，it suggested increasing the lime and fly ash content to solve the problem of oil obstruction on solidified material and of blocking on water migration as to heavily oil contaminated soil.

The glacial deposit is a typical soil–rock mixture. Its mechanical property is strongly affected by its structural composition. The bearing capacity of glacial deposit losses gradually when it suffers from gravity or other kinds of loadings. In this study，the algorithm of random rock block generation was used to reconstruct the meso structure of the glacial deposit. The ultimate shear strain under uniaxial pressure was used as a parameter for failure analysis. The deformation and failure of the glacial deposit with different structures and composition under uniaxial pressure was then simulated to understand the deformation process and failure law. Numerical simulations indicate that：(1) The glacial deposit under uniaxial pressure exhibits a significant phenomenon of getting round stone blocks during the shear deformation and failure process；(2) Both the shear strain zone and the ultimate shear strain increase with the increase of the content of rock block, besides the relationship between the ultimate shear strain and the content of rock block experiences an exponential growth. Results from the shear deformation and failure analysis of the glacial deposit with different inclinations of rock blocks show that：(1) The distribution of the shear strain zone under axial pressure always has good uniformity with the inclination of stone blocks；(2) The relationship between the ultimate shear strain and the inclinations of rock blocks takes on a shape of Λ. The random structure reconstruction method and the failure law of the glacial deposit can provide theoretical and technical reference for engineering safety and comprehensive reinforcement.

In order to study the influence of calcium carbonate content on the engineering properties of sand，the laboratory tests on four grain groups of sand with different calcium carbonate content are conducted. The characteristics of particle breakage and shear strength of sands are analyzed，and the results show that：The relative breakage increases with the increment of calcium carbonate content and the grain size. With the increase of the normal stress，the effect of calcium carbonate content on relative breakage becomes more obviously. The influence of calcium carbonate content on sand shear strength is significant，the friction angles increases with the increment of calcium carbonate content，and the larger the particle size is，the more obvious influence appears. The friction angle of small particle with high calcium carbonate content are close to that of large particle with low calcium carbonate content. Considering the effect of calcium carbonate content and particle size，an index named carbonate content index is suggested，and the soils are classified based on it.