The mesoscopic test device developed studying the crack process of coal and rock under double shear  was used in the shear test at different stress conditions. The acoustic emission and image processing techniques were employed to measure the mesoscopic cracking propagation process and the mesoscopic cracking extension space distribution. For the double shear test under compression and shearing，the damage of the surface of the specimen is not visible in most of the period of loading process and the surface cracks occur just before the shear stresses reach the peak value. When the shear stresses are nearly reaching the peak，the rate of Hit has a sharp increase indicating that there are already cracks inside the sandstone，while on the surface there are no cracks，and the tiny cracks can only be seen after a period of time. Presumably，the cracks developed from inside to outside. After the macroscopic damage，the left and right sides of cracks show a splayed or trapezoidal distribution. Because the internal shear failure of rock mass is mainly caused by the vertical shear force and the sand grains possess the different geometric and physical properties，the main crack along the shear plane extended irregularly. Cracks always occur in the edges of mineral particles like quartz，feldspar etc which are the weakest links of sandstone. As the shear stress level increases，the cracks will cross over the mineral particles and form transgranular fractures. This phenomenon is often seen in quartz grains because of its specific relevant microstructure features.

The large deformation characteristics of half coal rock roadway in Dongsun Coal Mine was found through a large number of deformation survey. The deformation occurred mainly on two sides of the roadway especially at the lower part of the sides. The rock fractures were inspected and the laboratory tests were conducted. The roadway rocks were found to have low strengths，to swell and even to be disintegrated by water and to have the diameter of loosen circle about 4 m. The main reasons for the damage of rock-coal roadway and the instability and the failure of roadway support were found to be the lower strength of rock and the developed rock joints and fissures(under the action of the external environment and disturbance) leading to the expansion and crushed deformation together with the stress superposition and rock creeping leading to the large deformation. A supporting system with the anchor，nets，cables and beams around key structures of the truss and anchor rope was proposed according to the roadway supporting principle. Theoretical analysis shows that the side supporting，namely the truss and the anchor rope are very important in transmitting forces and increasing the force carrying area of two side coal walls and thus improving support capacity. A buckle device was designed based on the mechanical characteristics of the truss，the anchor rope and the coal and rock deformation，which can improve the capacity of bending resistance of truss and anchor rope. The application of the system showed that it could stabilize the side wall，strengthen the roof and restrain the floor heave etc. to achieve an overall improving of the stability of roadway.

A relationship between the damage variable and the loading time has been obtained from the rheologic-ultrasonic tests of salt rock. On the basis of the classical three elements model，a fractional derivative three elements model for salt rock considering the damage evolution was established employing the theory of fractional calculus and damage. The model is structural concise and has less fitting parameters. The parameters of the model can be determined by the fitting analysis of least-squares using the data from the uniaxial rheological tests. The fractional derivative three elements model can fit the three stages of rheologic of the experimental data of the salt rock with high accuracy and is better than the classical one in characterizing the tertiary rheological stage. Furthermore，it is shown that the classical three elements model is a special case of the new model.

The surface displacement field of slope stabilized with piles in physical model tests was obtained using the computer aided inspection. The variances D(X) as the characteristics variable of the surface displacement field at different loading levels were calculated and used to describe the whole deformation and failure process of the slope. The dynamic parameter of slope displacement field and the fractals-Hurst index of variance of the surface displacement field were determined by means of R/S analysis. Experimental results show that the variance D(X) of the surface displacement field can be used to describe the formation and penetrating of the cracks and the failure of the slope. The severe deformation localization occurred on the slope surface and the cracks were developed. The varianceD(X) increased sharply when the deformation localization occurred. It is found that the Hurst index of the surface displacement field variance had a trend of low value-increase-dropping during the process of landslide. The Hurst index of variance of the surface displacement field decreases before the destabilization of the slope.

A series of triaxial compressive tests and CT scanning tests on dense sandstones were carried out. The CT images of failure cracks in rocks under different confining pressures were obtained. Using the image processing technique and the statistic principle，three-dimensional geometric models of failure cracks are established. Based on these three-dimensional models，the influences of confining pressure on geometric form and distribution features of failure cracks were analyzed. The energy theory was employed to reveal the intrinsic energy mechanism of crack growth characteristics in rocks subjected to triaxial stress. The results show that the confining pressure had great effects on the forms，the quantity and the special distribution features of failure cracks in rocks. When the confining pressure value is lower，the great number of the failure cracks occurs with complex formation. When rocks are completely fractured，the main cracks and secondary cracks cross each other forming a crack network. When the confining pressure is higher，the number of main cracks decreases and secondary cracks disappear. The cracks network with complicated geometrical form is replaced by linear failure cracks in similar. The confining pressure has significant influences on the characteristics of energy dissipation and energy release of the failure cracks. With the increase of the confining pressure，the releasable elastic strain energy increases linearly and the dissipation energy gradually decreases. Under the lower confining pressures，rocks have more dissipated energy leading to a large number of failure microcracks with complex geometric formations. While under the higher confining pressures，rocks have less dissipation energy leading to less failure cracks with the regular geometric formations.

The engineering classification in rock slopes is not included in the current standard of engineering classification of rock masses(GB50218—94). This paper presents the engineering classification method for rock slopes(BQ-R Slope) based on the quality index of rock mass BQ. In this method，several modified factors are employed as to correct rock mass basic quality，and the engineering rock mass classifications for rock slopes are determined by the modified rock mass quality，and the evaluation for stand-up time of rock slope in correspondence with each class of rock mass is further proposed. The employed factors consist of the type and the persistence of major structural planes，the relationship between orientations of structural planes in rock mass and rock slope surface and the groundwater conditions in rock slope. The presented method is verified through applications to four rock slope projects and ten slope sections in total. It is found that the engineering classification and the corresponding evaluation results of each slope section with the method proposed are generally in good agreement with the practical situation. This indicates that the presented method for engineering rock mass classification of rock slopes based on BQ index is appropriate.

At least 257 landslide dams were formed by Wenchuan earthquake in 2008. The aftershocks occurred after the major quake may influence the safety of those landslide dams. Dynamic characteristic parameters，including natural frequency and damping ratio，and distribution of acceleration amplification factor are the focus of the research of landslide dams. This paper presents the studies of large-scale shaking table tests on the dynamic characteristics and the acceleration distribution of landslide dams under aftershocks. The natural frequency，the damping ratio and the distribution of acceleration amplification factor of a model dam and their influencing factors are studied. The dynamic characteristic parameters of prototype landslide dams are calculated according to the similarity law. Two groups of shaking table tests are conducted to simulate the behaviors of two types of landslide dams：one with small particle size having the cohesive materials(dam I) and the other with large particle size not having the cohesive materials(dam II). The shaking table tests were conducted under different earthquake waves，different peak ground accelerations(PGA) and different water depths. The following conclusions are drawn：(1) The model dams have stable X-directional and Z-directional natural frequency and damping ratio. (2) Earlier shaking makes the natural frequency to decrease and the damping ratio to increase. The natural frequency of dam I is smaller than that of Dam II. The effects of water depth on the natural frequency of the two types of dams are different. (3) In vertical direction，acceleration amplification factor increases from the base to the top of the dam. The maximum accelerations occurred mainly on the top of the dams. In horizontal direction，the maximum accelerations occurred on the upstream and downstream surfaces of dam slopes，i.e. the surface amplification effect，which showed that the dam slope surfaces were prone to fail under earthquake action. (4) The earthquake waves with the predominant frequency close to the natural frequency of landslide dams induce the most prominent acceleration response. The earthquake in Z direction made the amplification factor of acceleration in X direction increase. The acceleration amplification factor decreases as PGA increases.

A yield function and a potential function were determined according to the twin shear unified strength theory. The hardening function of soils was established considering the development of soil strength during loading. An elastoplastic constitutive relationship under the complex stress state was proposed using the non-associated flow rule. The singularities in the constitutive model caused by the flow vectors of yield and potential functions and the hardening modulus were analyzed and resolved. The method of determining the parameters of the proposed model is presented. It was shown that the proposed constitutive model fit the strain softening curves from a conventional triaxial experiment of mudstone well.

Two types of physical models of sliding rock slope，one with the intermittent rock planes alone and the other with both the rock planes and secondary rock joints were built using similar materials，and tested in the centrifuge machine under different seismic loads. The dynamic response and failure mechanism of the two slope models were then recorded and analyzed. The test results revealed that the dynamic response of the sliding rock slope was sensitive to the frequency of input seismic load and the characteristics of the joint structure inside. The more complex the joint structures are，the more complex the response to the input load frequency and the greater the topographic amplification effect. The dynamic stability and failure mechanism is strongly affected by the joint structure characteristics of the rock slope mass. The rock slope model with both intermittent rock bedding planes secondary rock joints has the lower dynamic stability and a shallower failure plane than the model with only the bedding planes. The tensile failures of the secondary rock joints during the dynamic failing process give rise to the internal crash and lead to the rock debris flow.

The Servo-controlled triaxial rock testing system TAW–2000 was used to obtain the characteristic mechanical parameters of 32 group of rock samples of granite and diorite. The relationships of the initiation stress of dilation(crack damage stress) with the elastic modulus，Poisson?s ratio and the porosity were established resulting in a simplified model for crack damage stress. The elastic modulus is a measure of overall rock stiffness including the stiffness of grain to grain contacts and the intergranular matrix. The porosity is a measure of void space in the rock consisting primary of fissures，pores and open cracks. They are both closely related to the initiation stress of rock dilation. The initiation stress of dilation is correlated positively with the elastic modulus，and negatively with the porosity. A mathematical model for the initiation stress of dilation was obtained through data fitting the test results. The model can be used to calculate the initiation stress of dilation once the elastic modulus，the porosity and Poisson's ratio are known.

The mechanism of intensive venting pulverized coal to prevent coal burst was studied through laboratory tests and numerical simulation. The methods of determining the parameters such as the spacing and diameter of boreholes and controlling the coal burst were presented. It is found that the main functions of the spacing of boreholes for coal burst control is a function of borehole diameter，coal thickness，spill-over coefficient，is positive correlated with the spill-over coefficient or the borehole diameter，and is negative correlated with the coal seam thickness or the safe-raising deformability. The intensive venting pulverized coal applied at the stage of pre-depressurizing is to reduce the elastic modulus and raise the deformability and at the stage of relieving danger is to absorb the energy and increase the resistance. The ideas are applied to working front of number 1302 of Xinjulong Mine with a good result.

The rain spraying and fiber grating monitoring were used in a geomechanical modeling  test under different rainfall and support conditions to investigate the mechanical influences of different rainfall conditions on the bedding rock slope. The physical data including the displacements，the pore pressures and the supporting structure?s internal forces were analyzed. It was found that the displacement and the pore pressure variations occurred mainly at the surface of slope for the unsupported slope under the heavy rainfall condition within a short time，while the displacements became larger and the pore pressure dissipated faster in the front of the slope surface after the rain. The accumulation and dissipation of excess pore water pressure were the main factors influencing the slope stability for this type of slope. For the unsupported slope under light rainfall during a long period，the  displacements and pore water pressures also occurred beneath the slope surface. A large growth rate of displacements and a smaller decreasing rate of pore water pressure dissipation remained after the rain. The soften effect on interlayers due to rain infiltration may be the main influential factors to affect the slope stability in this case. While in the case of the supported slope, the displacements and the pore pressures were much smaller due to the restriction on the crack development which reduced the rain infiltration. The stresses of the supporting structure reached stable values quickly under the heavy rainfall condition within a short period and are adjusted slowly under the light rainfall condition within a long period. The maximum values of slope thrust 6 hours after the raining appeared in the different positions at different rainfall conditions. The maximum value occurred at the top of the supporting structure under the short and heavy rainfall condition and occurred at the middle of the supporting structure under the long and light rainfall condition. The magnitude of the latter was about 1.5–1.7 times of the former at the same location.

The Yangpeng tunnel in Northern Guangdong province on the expressway from Beijing to Zhuhai was investigated for the in-situ detection and recognition of the characteristics，the sizes and the specific locations of concealed structural damages(defects) of the carbonate rocks using the technologies of electromagnetic wave perspective imaging between holes and Color-CT tomography imaging. The results from the electromagnetic wave perspective imaging between holes and the Color-CT tomography imaging suggest that the fracture of the fine structural damage in the carbonate rocks is the minimum recognition units. The minimum recognition units are developed into karst tunnels linking the deep rock surface，and thus leading the geological disasters of ground collapse and inrushing of water and mud in the tunnel.

The model tests using the rock similar materials were carried out to study the effect of height-diameter ratios and characteristics of the filled joints. The uniaxial compression and shear tests were performed with three types of specimens including ones without joints，ones with cruciform joints and ones with intersecting parallels joints. The failure modes of the three types of specimens are similar in general trends with X-shaped conjugated plane or single plane of shear failure under compression and shear tests. Under the uniaxial compression，the performance of intact specimen is clearly affected by its size，and the strength of jointed one is significantly affected by the weakening of the structure depending on the joint density and the filling materials. The elastic modulus E and the cohesion c have no significant difference for the two kinds of jointed specimens，while the internal friction angles are obviously affected by the joints and their fillings.

The hydraulic fracturing field tests to weaken the hard K3 upper roof above coal layer were conducted  when severe problems occurred in the open-air and crossheading strata at Tashan Coal Mine. The water pressures in the boreholes and water oozing from bolt locations at two sides of roadways were monitored during the process of hydraulic fracturing to analyze the range of influence of hydraulic fracturing. The characteristics of weakening the hard roof by hydraulic fracturing were analyzed according to the step size of periodic pressure，the dynamic loading factor，the deflections of roof，the displacements of roadways，the statistical analysis of rib wall and gas discharge before and after hydraulic fracturing. It was found that the range of grooving fractures produced by hydraulic fracturing was no more than 55 m. Three types of the pressure-time curve of crack propagation in the coal and rock mass were obtained. The step sizes of periodic pressure are 18.69 and 16.76 m respectively and the average periodic dynamic pressure factors are 1.69 and 1.53 respectively before and after hydraulic fracturing. Both the deflection of roof and the displacement of roadways were greatly reduced and the roof of the roadways remained unbroken. The average depths of coal wall rib spalling were reduced from the original 31.18 m to 7.06 m. Besides，the gas release is relatively stable. The gas density at the upper corner was reduced from the original 0.20% to 0.15%. Meanwhile，the completeness and strength of the roof at the working front were weakened and roof was dropped as working front proceeds.

Inrush accidents generally happen in soluble rock tunnels during underground constructions. However，the number of inrush disasters reported in non-soluble rock tunnels have been increasing recently. They can lead to serious disasters and huge economic losses in tunnel construction. Cases studies were thus carried out and the analysis of three inrush accidents revealed that the causes of the inrush in non-soluble rock tunnels were due to the effects of excavation and blasting disturbance leading to the water and fragmental materials occurred in the fractured and weak zones flowing into the tunnels under their own pressures. The risks carrying environment must have the required physical，spatial and triggering conditions simultaneously：the physical conditions refers to the existence of abundant water and in-situ or exogenous fragments including gravel，sand and mud，etc.；the spatial condition refers to the fracture zone and the weak zone storing and transferring the inrushing materials；The triggering condition is the disturbance to the rock caused by excavation and blasting during the tunnel construction. The predication of inrush disaster in the construction of non-soluble rock tunnels is therefore to identify the fracture and weak zones containing the potential inrushing materials and the components and cementation level of material in two zones a head of the front face of tunneling. A comprehensive geological and geophysical detection and drilling scheme was then carried out to according to the material and spatial conditions in inrush disaster；The characteristics of seismic dynamic response of the parameters such as the reflection amplitude ratio and the wave axis similarity to anomaly geological objects in tunnel geologic prediction(TGP) were constructed. The approach was applied to the fault fracture zone F17 in anterior tunnels. The macro engineering geological analysis，geological investigation and experiments in excavated sections and the trends tracking were performed to reveal the statistical and mechanical characteristics of the surrounding rocks. The long range TGP and the short range ground penetration radar detections and the horizontal drilling were performed to identify the risks containing environment of inrushing disaster in the section unexcavated. The precise locating of the position，the scale and the spatial distribution of the fault fracture zone were thus be achieved. The material components within the zones and the cementation level were detected and the occurrences of inrush accidents were predicted successfully.

The susceptibility evaluation was conducted at Wanzhou district where landslide hazard largely occurred in the reservoir region of Three Gorges. Based on the results of the graded state of index factor and the correlation analysis，seven influence factors were chosen to be the evaluation indices including the gradient，the direction and the structure of slope，the stratum lithology，the geological structure，the role of water，and the land use. The frequency curve of landslide and the magnitude curve of information were drawn according to over 700 sample data of landslides. Catastrophe points on the curve were chosen as the critical value to determine the factor states on dividing the entire factors interval，so that to establish the system of susceptibility evaluation. Based on the grid data model of GIS and the method of weighted information value，the susceptibility evaluation was developed. The results show that the high and relatively high susceptibility areas are mainly the construction land，J2s2 and J2s3 stratum，area of reservoir water fluctuation，river net influenced area and urban area of Wanzhou city. The statistical results indicate that the areas with high and relatively high susceptibility taking up 1210 km2 in total are about 9.71% and 25.9% of the entire area under study respectively. The accuracy of the assessment is about 87%. This paper describes the theoretical methods and technical route of landslide hazards susceptibility evaluation in the district. The research provides a technical support for the regional landslide disaster prevention and forecasting and provides a theoretical guidance and technical reference for the nationwide county landslide hazards evaluation.

Laboratory tests were carried out to study the mechanical properties of coal-serial sandy mudstone under the temperature from 25℃ to 55 ℃ using the test system of rock mechanics RMT–150B and the temperature chamber GD–65/150. The complete stress-strain curve，the peak stress，the peak strain，the elastic modulus and the deformation modulus of the sandy mudstone under investigation were affected by the temperature conditions. As the temperature increases，the peak stress and the peak strain decrease gradually，but the peak stress and the peak strain decrease with a different values depending on whether the temperature is lower or higher than 40 ℃. The peak stress decreases 22.1% if the temperature is between 25 ℃ to 40 ℃ and decreases 4.3% between 40 ℃ to 55 ℃；The peak strain decreases 12.9% if the temperature is between is between 25 ℃ to 40 ℃ and decreases 29.9% between 40 ℃ to 55℃. The elastic modulus and the deformation modulus both decrease linearly with the increasing of temperature. The results are useful for the efficiency and safety of deep coal mining.

Based on a concise mechanical model of two-phase discontinuous media such as saturated soil，a new expression of effective stress was derived. In the expression，the distribution of total stress depends on the porosity n and the coefficient of pore pressure's transfer ?(?∈[0，1]). The new expression was then applied to Biot theory. Consolidation of a columnar sample was analyzed with FEM software Abaqus and solutions of pore pressure and displacement were obtained. The results from the new equations were compared with those from original Biot theory. From the permeability data in relevant literatures，values of ? of clays in a reasonable range of 0.32–0.54 were obtained. With the same modulus and coefficient of permeability，the consolidation process speeds up as n and ? decrease and Mandel-Cryer effect becomes more significant. When n = ? = 0，the consolidation process becomes instantaneous. A transition is presented from the consolidation behavior of porous media to that of continuum mechanics. The consolidation theory of the two-phase discontinuous medium bridges the traditional consolidation theory and the elastic theory；the confirming the rationality of the mechanical model of two-phase discontinuous medium indirectly.

A series of triaxial shear tests on municipal solid waste(MSW) with the maximum vertical strain of approximately 50% were carried out by a modified triaxial apparatus. The test results show that MSW samples failed under large-strain condition and the failure strain decreases with the increasing of the landfill depth. The basic and reinforced phases of MSW were separated and triaxial consolidated drained(CD) shear tests were carried out on each phase. The results show that the stress-strain curves of both basic and reinforced phases have the strain-hardening characteristics. The structural formation and reinforcement effect of the organic fibers in basic phase were described through sieving and microscopic observation on granule groups. Then CD tests of several granule groups were carried out and the results demonstrate that every group has a strain-hardening stress-strain curve except the group with particle diameter smaller than 0.075 mm. The stress-strain curves of the basic phase before and after burned were compared，showing that the organic fibers will not play the reinforcement effect until a certain value of strain is reached. Fiber fracture and slipping along the interface seem to exist during shearing. Finally，based on the results of triaxial shear tests，methods for determining the shear strength parameters of triaxial consolidated undrained shear(CU) and CD tests were discussed respectively.

The stiffness of buildings was ignored in conventional analysis in calculating the influence of tunnelling on adjacent buildings. In this research，the field monitoring was carried out on both surface settlement and building deformation along a construction section of Metro Line 2 in Wuhan. The monitored results are very different from the predicted ones ignoring the building stiffness，which indicate a significant influence of building stiffness on its deformation. Numerical simulation considering the small strain stiffness in the soil constitutive model was then carried out. The results of the simulation revealed the considerable influence of building stiffness not only on the surface settlement but also on the sub-surface soil deformation. The mechanism of this complex tunnelling- soil-building interaction is discussed. The results demonstrate the importance of considering building stiffness when analyzing the influence of tunnelling on buildings and piles.

A series of the vane shear tests and the triaxial tests investigating the undrained shear strength of typical ocean silt under low stress conditions were carried out to understand the submarine geological hazards such as shallow landslide. It was found that the degree of consolidation affected the vane shear strength of silt and the vane shear strength decreased as the excess pore pressure increased. The triaxial undrained shear strength of silt is affected by the over consolidation ratio and the confining stress level but not by the shear strain rate. All samples reached the critical state in the triaxial tests and the shear strength at the critical state increased with the increase of the over consolidation ratio and the confining pressure. The vane shear strength and the triaxial undrained shear strength at critical state were normalized using the mean effective stress and the good consistency was found between them. The critical strength line of marine silt under low stress condition was obtained，which explained the reactivation of the submarine landslide by the storm wave in the Yellow River delta.

A formula is derived to calculate the vertical earth pressure of circular tunnels in dense sand and hard clay grounds. The formula considers the coefficient of lateral pressure and the effect of oblique slip surface beside the circular tunnel on the basis of the hypothesis of Terzaghi theory. A method to calculate the lateral pressure coefficient is established in order to solve the proposed formula. A quantitative relationship between the vertical pressure and the factors such as the lining stiffness and the ground stiffness is also derived. The relationship shows that the decreasing of the lining thickness or the increasing of the elastic coefficient of resistance of ground lead to the increasing of the lateral pressure coefficient and the reducing of the vertical pressure. The results from the proposed method，the upper bound of limit analysis and previous experiment results are compared and found to be close to each other. The proposed method is simpler than the upper bound method and is suitable for both shallow circular and deep tunnels.