为探究切顶卸压自动成巷技术条件下的工作面矿压显现特征及机制，以塔山煤矿8304工作面为例，在对切顶成巷技术原理及工艺流程进行总结的基础上，提出具体成巷设计，随后通过现场监测、数值模拟以及理论推导等手段，对工作面的矿压分布特征及演化过程进行分析。监测结果显示：(1) 工作面中部来压步距最短、来压强度最高，且受留巷切顶影响，工作面来压步距及强度分布呈现非对称性；(2) 留巷侧顶板的周期来压步距较之未切缝侧较大，平均增幅为4 m，但来压压强降低，平均来压压强降低2.1 MPa，降幅9.2%，峰值来压强度降低10.2 MPa，降幅25.0%，切顶卸压效果明显，且峰值压力受切顶卸压影响更大；(3) 顺槽切顶于工作面的横向影响范围大致为29.75 m，越靠近切缝处影响效果越显著。数值模拟进一步发现：顺槽预裂切顶对工作面来压在走向方向上的超前影响范围约为20 m，超前影响范围内，影响程度随超前距离增加逐渐减小；在滞后工作面30 m范围内，滞后工作面距离越远，顺槽切顶卸压影响越大；在滞后工作面30 m之后，顺槽切顶影响幅度基本维持不变。

A method for transforming the ultrasonic velocity of the drilling core to the seismic velocity of the corresponding strata beneath the surface was proposed. According to the rock type，the ultrasonic velocity of rock blocks is converted to the seismic wave velocity using different conversion coefficients，and the velocity is modified using an empirical equation，considering the effects of water saturation，temperature and pressure. The seismic wave velocity of rock body is obtained from the seismic wave velocity of a rock block，by using the integrity coefficient Kv of rock mass and the volume joint number Jv of rock body. To testify this method，5 drilling cores were chosen from the polymetallic deposit in Huayangchuan，and the ultrasonic velocities of the samples were measured and converted into the seismic velocities according to the method. Comparisons indicate that the two sets of velocities are very well correlated in terms of the depth change.

In order to study the creeping properties of salt rock，uniaxial compression creeping tests under different axial stresses were carried out on salt rock specimens. The test results indicate that the creep strain and the steady creeping rate of salt rock both increase gradually and exponentially with the increasing of axial stress. The creeping process of salt rock is nonlinear with respect to the axial stress and creeping time. The higher the axial stress level and the longer the creeping time，the more obvious the nonlinear characteristic. To determine the long term strength of salt rock，an improved inflection point method for steady creeping rate-stress curve was proposed. The long term strength of salt rock determined with the method is very close to that obtained from the inflection point method for isochronous stress-strain curves. The new method can provide some insight into the similar studies. A new whole process creeping model for rocks under uniaxial compression was established by taking the inverse of S shaped function. The creeping test results of salt rock were used to evaluate the reasonability of the creeping model. The comparison of prediction curves and the test results shows that not only the primary creeping stage and steady creeping stage under the low stress level，but also the whole creep process(the primary creep stage，steady creep stage and accelerated creep stage) under the high stress level of salt rock can be described by this model. The new creeping model can accurately reflect the three stages of rock creeping with a unified expression，and overcome the shortcomings of the combined component model which is segmented. In addition，the expression of the model is very simple and convenient for application.

The influence of different intervals between holes of explosive load on the crack propagation was investigated through the dynamic caustics test and numerical simulation. With the increasing of the intervals between holes，the explosive cracks show no direct penetration any more，rather the deflection of cracks occurs in a “hand in hand” shape. With the increasing of the intervals between holes，the cracks propagation oscillates in the process of expansion and the oscillation is more notable in the area that cracks meet. The peak values of the propagation velocity of main cracks，the stress intensity factor and the stress at the area of cracks meeting all depend on the interval between holes. If the interval between holes is smaller，the peak values is larger，which is beneficial to the directional fracturing.

An approach for simulating the nonlinear response of surrounding rock was employed to analyze the excavation of circular tunnels in strain-softening rock masses. The proposed procedure was implemented in a finite element code based on the classical theory of plasticity in which the three-dimensional nonlinear Hoek- Brown strength criterion(GZZ strength criterion) is employed. This criterion not only inherits the advantages of the two-dimensional Hoek-Brown strength criterion but also can take account of the influence of the intermediate principal stress. The stress，strain，displacement and plastic zone in surrounding rock were solved with the numerical method according to the classical elastic-plastic theory. The traditional two-dimensional Hoek-Brown strength criterion was found to underestimate the deformation of surrounding rock. The calculated radii of plastic zone and softening zone in surrounding rock and the maximum strain in tunnel wall with GZZ strength criterion are much larger than those calculated with the traditional two-dimensional Hoek-Brown strength criterion. The maximum circumferential stress is located at the elastic-plastic boundary. The gradient of circumferential stress in the plastic zone is sharply changed，which shows the transition from the softening region to the residual region. In the softening region，the radial and circumferential strains in surrounding rock are relatively small. In the residual region，the stresses are relatively small，but the strains can reach scores of times of those in the softening region. The strain-softening behavior of rock masses reduces the ground stress near the tunnel wall in the plastic zone，but the tunnel deformation was greatly increased at the same time. When the internal supporting pressure is small，the deformation in the surrounding rock may increase scores of times due to the effect of strain-softening behavior. Similarly，under the same convergence deformation，the internal supporting pressure may increase scores of times due to the effect of strain-softening behavior. Therefore，the strain-softening behavior of the surrounding rock is the key to the large deformation of tunnel in the high stress area. It is critical to consider properly the strain-softening behavior of the surrounding rock in the design and calculation of the tunnel supporting structure.

The shear strength characteristics and the wearing mechanism of rock joints in the shear process are very important for analyzing the stability of rock mass. 3D laser scanning and numerical controlled engraving were used to produce the natural joints in the specimens of sandstone，marble and granite. The point cloud registration and the fidelity rate test were carried out based on the standard ICP algorithm of four elements. The direct shear tests with acoustic emission monitoring to three kinds of natural rock joints under different normal stresses were carried out. The overlapping of the point cloud data of rock joints before and after shear test was realized with the algorithm of point cloud registration. The wearing characteristics of natural joints were analyzed. The experimental results show that the natural rock joints produced by engraving are of high accuracy and lead to consistent results. Based on the AE characteristics，the shear process can be divided into three stages：I-frictional sliding stage，II-shearing and gnawing stage，and III-residual friction stage. Comparison of the 2D and 3D morphology before and after the shear tests show that the front slope slides，the inhomogeneous wearing damage and local gnawing of the convex point occur on meso-scale，and the local and inhomogeneous failure zones occur on macro-scale.

A cement mortar plate containing a single flaw was used to simulate the rock mass. The flaw in each sample has an angle with respect to the loading direction from 0° to 90°. A modified split Hopkinson pressure bar (SHPB) system was used to carry out the dynamic compression test to the plate specimen and a high-speed imaging system was used to record the crack propagation under different loading rates. The surface of the plate specimen was coated with a speckle pattern and the digital image correlation(DIC) technique was adopted to analyze the characteristics of the fracturing process. The testing results indicate that the failure of the cemented mortar plate with a single flaw is mainly the X type and the strength of the specimen increases with the loading rate under a given orientation of flaw. The orientation of the flaw is the main factor influencing the strength of  specimens. The shear cracks and tensile cracks were observed to be the dominant crack types. The crack propagation path，stress field，crack initiation and propagation process were also analyzed with the DIC method. The correlation between the dynamic initiation fracture toughness and the classical criterion of mixed cracks under different loading rates and different joint angles was analyzed.

In order to optimize the rock support design under the dynamic loading conditions such as rock bursts or coal bumps，weight-dropping tests were carried out to two samples of the constant-resistance-large-deformation (CRLD) bolts which have widely been used as the rock support in longwall mining based on gob-side entry retaining without coal pillar(110 mining method). Analytical models including the critical impact height，impact working resistance and displacement for the CRLD bolts were established based on the stress wave and elastic dynamics theories. The weight-dropping tests under different dropping heights on the bolt samples were conducted. The entire time curve for the impact working resistance under single impact has multiple peaks with the first peak larger than the static working resistance   and the others smaller than   and damped to zero due to the unloading waves created by the transmitting and reflecting waves along the bolt. Waveform analysis on the first peak in the enlarged time sale revealed the load-damping modes for the CRLD bolt under impact loading，i.e. the first phase is the multi-periodical oscillations with the decreased magnitude of the impact force and the second phase is the fast-damped frictional sliding motions. The theoretically predicted results have a good agreement with the testing data.

In order to study the effect of temperature and pressure on the pyrolysis characteristics of oil shale，12 hours of pyrolytic reaction experiments were conducted on cylindrical oil shale samples of 14 mm in length and 7 mm in diameter under the temperature from 300 ℃–600 ℃ and pressure 5–15 MPa. The X-ray micro computed tomography，mercury intrusion porosimetry and scanning electron microscope were used to investigate the variation of pore and fracture structures. The results show that temperature is the most important factor in changing the structures of oil shale. With the increasing of temperature，the pyrolytic cracking intensifies progressively. The total pore volume and porosity both increase gradually，especially in the range of 300 ℃ to 400 ℃. With the increasing in temperature，the transition pores expand and interconnect to each other，forming larger pores. As a result，the proportions of transition pore and mesopore increases gradually. The fractures of different scales are generated，and the number of fractures increases continuously. The fracture area density of big fracture at 600 ℃ is 8.1 times as high as that at 300 ℃. To a certain extent，the increasing of the external pressure and thermal stress caused by pyrolysis act together to promote the expansion of the original crack and the birth of new cracks，which results in the increasing in the total pore volume and the number of fractures. The porosity and fracture area density reach the maximum at the pressure of 15 MPa，and the maximum porosity is 51.6%. The pyrolytic cracking of oil shale is affected by the thermal stress due to the expansion of mineral particles and pyrolysis of kerogen. The coupling of temperature and pressure increases the degree of pyrolytic cracking and also promotes the generation，expansion and development of pore and fractures.

Oil sand reservoir is filled with the rich viscous bitumen，so the high temperature can make a significant influence on the reservoir stress/deformation in thermal recovery. High-temperature and high-pressure triaxial compression test is usually used for the modeling of reservoir deformation. To acquire the stress-strain response as well as the mechanical properties under the stress/temperature conditions corresponding to thermal operations，the effects of temperature on mechanical properties of oil sands in Athabasca，Cold Lake，Faja(Venezuela)，and Karamay were studied. The microstructure of different oil sands was investigated to interpret the temperature- induced mechanical properties. It was concluded that the thermal effects on different oil sands differ greatly and that oil sands in Cold Lake and Karamay are more thermosensitive. According to the statistical analysis for normalized parameters under varying temperatures，it was found that the thermomechanical response for different oil sands can be divided into three patterns，determined by factors like the content of fine or bitumen，the degree of mineral grain crushing/rearrangement，the viscosity of bitumen and the cements and cementation types.

The movement of overlying strata and the effect of retaining roadway under the automatic roadway forming by roof cutting and pressure releasing without coal pillar mining(working method 110) was studied through physical modelling test to the working face 5–200 of Dianping coal mine. Four kinds of rock strata including the sandy mudstone，medium sandstone，limestone and coal rock were constructed by using gesso，fine sand，barite powder and other similar materials. Six excavation steps were designed along the coal seam strike according to different propulsion scales. The collapse of overlying strata under different excavation stages and the deformation characteristics of surrounding rock of retaining roadway were observed. In the experiment，the visible imaging，high-precision digital speckle imaging and artificial sketching were used to observe the regularity of rock strata caving. The research results show that when the working face is excavated upto 12 m，the immediate roof collapsed completely. When the working face is excavated upto 16 m，the main roof collapsed completely. When the working face is excavated upto 20 m，the overlying strata collapse reaches a stable state. Under the influence of roof cutting，in the early stage of overlying strata movement，the rock strata on the side of roof cutting collapses earlier than that on the side of the uncut side，and the displacement is larger than that of the uncut side. In the later stage，due to the dilation of the strata，the filling effect of the gob on the side of roof cutting is better，the overall vertical displacement is smaller than the uncut side，and the abscission layer is concentrated mostly on the uncut side. The whole field displacement contours and the displacement monitoring of roadway roof and floor indicate that the maximum vertical displacement of the roof is 10 mm，the minimum vertical displacement of the floor is 4 mm，and the stability of the surrounding rock is better. It is shown that through the presplitting of the cutting slots on the roof，the surrounding rock pressure can be effectively relieved and the surrounding rock deformation can be controlled.

The stability of the goaf support system is the key to safe production in gypsum mines. A pillar-beam support system in plastic zones was constructed，and the beam and pillar were taken as the energy releaser and energy dissipater respectively. A cusp catastrophe model was established based on the energy theory，and the condition of instability of the support system was obtained. The results indicate that the instability of support system is caused by the incompatibility of energy release，energy dissipation and geometric deformation. When ?＞0，the energy released from the support system is compatible with the geometric deformation. The support system experiences a quasi-static process from the static state in the bottom leaf to the static state in the top leaf along Path I. When ?＜0，the energy released from the support system cannot be in tune with the geometric deformation. The support system experiences a catastrophic process along Path II. The evolution from the static state in the bottom leaf to the static state in the top leaf is not progressive，but catastrophic. The redundant energy released in this process leads to the mechanical instability of the support system. The sensitivity of the geometric parameters of the support system was analyzed as well. These parameters are ranked according to their sensitivity from high to low，as is shown below：beam thickness＞plastic zone width＞room span＞pillar width＞pillar height. Based on the actual engineering examples，the goaf was classified according to the geometric parameters. The energy catastrophe theory was applied to analyze the stability of support system of goaf in different classes. The analysis results showed that class D goaf should be labeled as the unstable zone，which was consistent with the result of field research. The energy catastrophe theory is thus shown to demonstrate the non-linear mechanical mechanism of support system instability in room-pillar mining goaf.

The study on physico-mechanical and transport properties of granite under the rapid cooling is of great significance for understanding the variation of reservoirs of hot dry rock. The rapid cooled granite from 20 ℃ to 600 ℃ was tested to investigate the physico-mechanical properties of the samples rapid cooled from different temperatures. The permeability of the cylindrical samples was measured with the pressure pulse decay method. With the temperature increasing，the density，longitudinal wave velocity，compressive strength，elastic modulus and tensile strength of the rapid cooled samples decrease monotonously，and the permeability increases initially slowly and then sharply. This is because that the inhomogeneous and anisotropic thermal expansion of the mineral grains leads to the thermal cracking of the granite at the slow heating and heat preservation stage. Upon the   rapid cooling，the temperature gradients generate the stress along the radial direction of sample and induces more cracks，which ultimately leads to the deterioration of the physic-mechanical properties and the enhancement of permeability. Under the rapid cooling，the brittle-ductile transition temperature of granite is between 500 ℃ and 600 ℃，below and above which the granite exhibits mainly the brittle failure and the ductile failure respectively. Under slow heating，rapid cooling and unconfined condition，the threshold temperature for the variation of permeability of granite is 400 ℃. The damage factor based on the elastic modulus reflect accurately the deterioration of the mechanical properties of granite，while the damage factor based on the longitudinal wave velocity overestimates it.

In-situ pyrolysis is the mainstream trend of oil shale exploitation in the future. The in-situ heating methods are mainly divided into conduction and convection heating modes. In the process of in-situ pyrolysis of oil shale，the pores are the main channel for oil and gas seepage. The connection characteristics of the pore structure affect and control directly the production process of pyrolytic oil and gas. Therefore，in this paper，the cylindrical oil shale samples of ? 8 mm×25 mm are heated through conduction and convection with muffle furnace and steam boiler respectively. The maximum heating temperature is 550 ℃. With the micro-CT and 3D digital core reconstruction technology，the size，distribution and evolution of pores of oil shale before and after heating were studied comprehensively，and the differences of different heating modes on pore structure of oil shale were analyzed. The results show that the porosity is 2.90 times of the original porosity after the conduction heating. However，after the steam convection heating，the porosity is 3.51 times of the original porosity. The convection heating heats the oil shale evenly and the area of heat exchange is larger，so that the pyrolysis of the solid organic matter in the oil shale is more thoroughly，prompting the pores in the oil shale to expand rapidly and to connect into the large-scale connected pore groups. In addition，the convection heating steam quickly carries away the shale oil that adheres to the pore wall and remains in the dead-end of pores，which improves the connectivity between the pores and increases the pore diameter effectively and forms a better connected pore structure than in the conduction heating. The steam carries away oil and gas together simultaneously，which increases the recovery ratio of oil and gas. Therefore，convection heating is the preferred heating mode for in-situ pyrolysis of oil shale.

In order to obtain the accurate circumferential deformation and the mechanical characteristics of post-peak dilation of the standard cylindrical specimen during the whole process of stress-strain test，a new type of circumferential deformation test method for standard specimens was proposed with the angle measurement based on the MTS chain circumferential extensometer. The principle of measurement was described in the paper. A chain rolling belt connected with the angle sensor is used in the system to twine around the standard circular specimen. The data acquisition system programmed by LABVIEW is used to achieve the automatic high precision acquisition and rapid recording. The measurement accuracy is 0.004 mm and the measurement range is 30 mm，which is adequate for many loading environments such as the gas-solid coupling loading and the tri-axial loading. The reliability and accuracy of this system were verified by the MTS chain extensometer and the close-range photogrammetry. The adsorption degradation test of coal with different gases was carried out. The briquettes with the same prefabricated strength were filled with the gases under the same pressure(He，N2，CH4 and CO2)，and then the axial loading test was carried out after the full adsorption. The deformation and instability of coal body during loading were obtained. The effects of gas properties on the volume expansion，the strength and fracture development of coal were compared and analyzed. The experimental results show that with the improvement of gas adsorption，the coal enters the expansion stage from the compaction stage earlier，and the position of the ultimate load value and volume expansion point reached earlier with the sequence for gases：CO2＞CH4＞N2＞He. The impregnation of He without adsorption does not degrade the coal，but the coal body strength is significantly reduced by adding the adsorptive CO2. The peak strength decreases by 32.05% after the CO2 adsorption under the pressure of 1.0 MPa. The whole system is made of modules and can work synchronously with the axial LVDT displacement meter.

When a slope slides into water，it creates the impulse waves whose effects may be catastrophic. Assessing the risk posed by such events requires the estimation of the characteristics of waves，especially in the near-field zone. The momentum rate from a landslide upon impacting the water body is the driving force for the generation of impulse waves. The theoretical relationships for the maximum near-field wave amplitude generated by three-dimensional deformable landslides are derived considering the momentum transfer under the hydrostatic and hydrodynamic assumptions. The three-dimensional experiments on tsunami generation by landslides were carried out in a wave flume. The comparisons between the measured values and the predicted wave amplitudes using the novel momentum-based equations indicate that the maximum near-field amplitude generated by three-dimensional landslides is far less than the breaking limit of solitary wave，and thus the wave will not break in the near-field. The results from the theoretical equations are in agreement with the laboratory data if the landslide is completely submerged after deposition. However，for the slope sliding into the shallow water，if the water depth is below the critical depth，the measured near-field amplitudes decrease sharply with the decreasing of water depth，which is opposite to the theoretical relationships. The similar results were also obtained in the three-dimensional experiments by Mohammed(2010) and in Gongjiafang case. The near field characteristics of landslide generated impulse waves for the cases of deep water and shallow water should therefore be studied separately. After discussing the limitations of the theoretical models，a new momentum-based method for predicting the maximum near-field wave amplitude is thus proposed.

In order to study the bearing behavior of a single pile in sand under combined loads of vertical force V，horizontal force H and torque T，a special device for combined loads was designed and a series of model tests were carried out. The internal force-deformation under combined loads and the interaction curves of three loading components on the bearing capacity were obtained. The envelope of pile bearing capacity was obtained，and a simplified formula of the bearing capacity was given through dimensionless treatment and fitting. The results show that the effect of V and H leads to the reduction of torsional bearing capacity of the pile，for instance，the torsional bearing capacity is reduced by 66% under the combination of 0.6Vu-0.6Hu，compared with the ultimate torsional bearing capacity of pile shaft under pure T (Tu). Under combined loads，the pre-applied vertical load weakens the torsional bearing capacity of single pile，but improves the horizontal bearing capacity. However，the influence of H on the vertical bearing capacity can be neglected. There is a complex coupled relationship between the load components. The horizontal and vertical displacements of a pile increase with the increasing of T. The friction resistance and the horizontal reaction of piles interact，so the bearing capacity of composite pile cannot be evaluated simply based on the principle of superposition.

To reveal the variation of shear strength of unsaturated soil more intuitively and entirely，a nonlinear envelope shell model for shear resistance of unsaturated soil was put forward considering the fact that the shear resistance develops nonlinearly with the normal stress acting on the failure surface and that the friction angle varies nonlinearly with the matric suction. A method calculating the shear resistance based on the soil-water characteristic curve of unsaturated soil was suggested. The parameters in the suggested model are easily obtained without the additional tests. Moreover，comparing to Fredlund?s plane envelope model，the acquisition process of parameters is more objective，and hence，the uniqueness and accuracy of the calculation are guaranteed. The applicability and reliability of the suggested model for nonlinear shear strength of unsaturated soil were verified by comparing with some cases from literatures. Especially，this method can obtain more accurate shear strength for the unsaturated soil samples which are not easy to measure suction directly under high stress levels.

The influencing factor and the characteristics of deformation and strength of medium dense sand samples were analyzed based on the macroscopic theory of elasto-plasticity and triaxial tests in order to precisely predict the deformation of medium dense sand on site. The yielding criteria，the hardening law and the flow rule were formulated accordingly. The stress-strain curves change with the increasing of confining pressure. The slope of the linear section of stress-strain curves and the peak strength increase with the increasing of confining pressure. The softening section reduces and even disappears. The gradient of volumetric strain-axial strain curve remains as usual basically. The shear dilation decreases. Under the high confine pressure，the samples exhibit the shear contraction in the whole shearing process. Considering the confining effect and shear failure in medium dense sand，the internal plastic variable is expressed by the third principal stress and effective plastic shear strain increment. The internal plastic variable at peak is larger than 0.5 and much larger than that of rock. The elastic modulus increases exponentially with the increasing of confining pressure. Poisson?s ratio remains the same approximately. The maximum and minimum principal stresses vary linearly in the process of plastic deformation. The internal friction angle increases linearly，and the cohesion increases and then decreases exponentially. The dilation angle decreases with the plastic deformation under the low confining pressure，but it increases and decreases under the high confining pressure. The calculated curve is basically identical to the experimental data，indicating that the model is suitable for medium dense sand.

In this paper，a composite foundation combining short pile and anchor was proposed for the complex foundation conditions with overlying thick soil layer(4–7 m) and underlying moderately weathered rock in the Karst area for overhead transmission line project. In order to reveal the bearing mechanism of the composite foundation and to establish the corresponding design method to facilitate the better application to projects，the foundation with overlying silty clay and underlying weakly weathered limestone at the typical Karst area of Yangchuan in Guangdong province was selected as the site of field test. Six full-size foundations(1∶1) with different embedded depths and different anchor numbers were designed according to the uplift load on the tower hanging the transmission line of 110–1 000 kV voltage in China. The load-displacement curves，ultimate uplift bearing capacities and foundation failure modes of the tested foundations were obtained in the pull-out tests on the site. It was concluded from the test results and theoretical analysis that the failure of the composite foundation is controlled by the ultimate uplift displacement when the anchor appears damaged. On this basis，a formula for calculating the uplift bearing capacity of the composite foundation was established，and the methods to determine the failure displacement and the allocation coefficients of bearing capacity of the composite foundation were proposed respectively. The correctness of the methods was verified by comparing with the field test results.

The equal vertical strains were assumed and the smear effect in subsoil surrounding the stone columns and impervious piles and the well resistances in the stone columns in vertical and radial directions were considered，so that the differential equations governing the consolidation of stone column-impervious pile composite ground were derived under the instant loading. The corresponding analytical solutions were developed under the PTIB condition，including the overall average degree of consolidation of this type of combined composite ground. The proposed solution was verified through the comparison with the results from finite element method. A parametric study was conducted using the proposed solution to investigate the consolidation behavior of the composite ground. The results show that the consolidation rate of the soft ground improved by the stone columns combined with impervious piles is much faster than that of the composite ground with impervious piles，but slightly slower than that of the composite ground improved by stone columns. The consolidation rate increases with increasing of the area replacement ratio and constrained modulus of the stone columns or the impervious piles，but decreases with the increasing of the two- dimensional well resistances in the stone columns when the diameter of the stone column is bigger. The effect of the radial well resistance on the consolidation rate is negligible when the diameter of the stone column is smaller. The disturbance of the subsoil surrounding impervious piles has negligible influence on the consolidation rate of the composite ground.