This paper summarizes the main research achievements associated with roadway strata control during 70 years since the founding of new China，including the geomechanics properties of rocks surrounding roadways，the features and mechanisms of surrounding rock deformation and damage，and strata control theories and techniques. The strength and structural features of sedimentary coal strata，the distribution laws of in-situ stresses in underground coal mines，and the distribution characteristics of coal mining induced stresses and their actions on the surrounding rock stability of mine roadways are introduced. It is pointed out that the deformation features of rocks surrounding coal mine roadways are staged pattern，rheology and impact，that there exist three damage types in surrounding rock including coal and rock damage，structure plane damage and rock structural instability，and that soft rock，intensive mining induced stresses and large deformation are distinguished features for roadway strata control in China. Five types of roadway strata control methods and principles，involving controlling broken surrounding rocks，controlling rock deformation，forming load bearing unit，rock modification and distressing，are discussed. The whole process control principles for surrounding rocks during heading are expounded，and the pretension rock bolting theory and support stress fields are especially introduced. The roadway strata control techniques are divided into five classes including rock surface support，rock bolting，rock modification，destressing and combined control，and the development history and applications of steel arches，rock bolts and cables，grouting，destressing with hydraulic fracturing and combined control pattern are discussed. Finally，the existing problems associated with roadway strata control in underground coal mines are analyzed，and the technical development prospects in the future are put forward.

Coal and gas outbursts are the most serious dynamic disasters in the process of coal mining，and unclear understanding of outburst mechanisms restricts the reliability and effectiveness of disaster early warning. Taking Sunjiawan outburst coal seam in Fuxin as the research object，the similarity experiments of coal and gas outburst with different mining depths were carried out using a self-developed true triaxial test device of coal and gas outburst and the DS5 series full-information acoustic emission signal analysis and testing system. The energy evolution process of coal and gas outburst was analyzed，and the relationship between acoustic emission parameter characteristics and precursor information of coal and gas outburst was established. The results show that the coal and gas outburst process has four stages including early incubation，late incubation，excitation-development and termination and in the process，the acoustic emission energy signals show “steady-rise-peak” variation，indicating that coal and gas outburst is a mechanical process of coal damage and energy accumulation. In the early stage of gestation，the AE energy is at a low level with a steadily rising accumulation，the low energy frequency dominates，and the outburst danger is weak. In the late stage of gestation，the AE energy increases greatly and high-energy frequency dominates，highlighting the risk. The difference of AE energy signals in different periods of outburst can be used as outburst precursor information to monitor the dynamic changes of coal and rock internal fractures in real time and further to guide outburst prediction and early warning. Based on acoustic emission energy，a quantitative index reflecting the danger level of coal and gas outburst in incubation period is defined，which provides scientific reference for the prediction and early warning of dynamic disasters in coal mining.

It is crucial for shale gas reservoir reconstruction to clarify the initial structure characteristics，the fracturing evolution rule and the formation mechanism of failure modes for shale. In view of this，in this paper，the in-situ micro-CT tests of shale under uniaxial compression condition are carried out，and the internal structure characteristics of shale and the its influence on shale fracturing evolution and failure mode are studied. Based on the test results，the internal structure change of shale under uniaxial compression condition is described，the fracturing evolution stage of shale based on the crack volume is analyzed，and the development degree and connectivity of 3-D cracks in failure shale are quantified. On this basis，two failure modes of shale under uniaxial compression condition are summarized，and the distribution characteristics of meso-scale minerals and their influence on failure modes of shale are analysed. In addition，according to the mineral distribution identified by CT images，the uniaxial compression simulation tests of numerical samples containing mineral bands are carried out，and the influence mechanism of mineral bands on shale failure modes are revealed. Relevant research results have important reference value for study of shale fracturing mechanism and mineral permeability-increasing mechanism of reservoir shale，and have clear guiding significance for the scheme optimal design of shale gas exploitation.

A systematic impact load test on the progressive failure of briquette coal under unilateral and biaxial constraints was conducted by using the restraint pendulum impact dynamic loading test device and the ultrasonic testing device，and destruction characteristics and energy dissipation law of coal samples during the impact process of different cycles until macro damage was analyzed. The results show that the damage of the samples increases in an inverted S form with the impact number. Under the unilateral constraint condition，the cumulative damages of the samples are the largest when the axial stress is 1 MPa，and with increasing the axial stress，the damage is greatly reduced. For the biaxial constraint condition，however，the coal sample is least likely to occur damage when both the horizontal constraint and the axial constraint stresses are 1 MPa. In the case of that the horizontal restraint stress remains unchanged and the axial stress increases gradually，the samples would be damaged significantly，especially at the final period. The evolution of progressive destruction of coal samples is explained from the aspect of energy dissipation，and the energy criterions of damage and destruction for two cases are given.

The Ya¢an—Xinduqiao section of the proposed Sichuan—Tibet railway is located in the geological structure intersection area of Sichuan，Yunnan and Tibet with extremely complex geostress. Research on the present geostress field in this area is conducive to the scientific construction of the Sichuan—Tibet railway. Based on the measured data of in-situ geostress by hydraulic fracturing method，the characteristics and distribution of in-situ geostress as well as engineering effects in the three sections including Ya¢an—Ludin，Luding—Kangding and Kangding—Xinduqiao sections of Sichuan-Tibet railway are analyzed. The results show that the main stress value has a good linear relationship with the burial depth，and that the maximum horizontal main stress increase gradients of the three sections are respectively 3.2 MPa per 100 m，2.7 MPa per 100 m and 3.6 MPa per 100 m，among which the growth gradient of Ya¢an—Luding section is the largest with a measured maximum horizontal main stress more than 51 MPa at 1300 m the burial depth. The orientation of the maximum horizontal principal stress in this area is NW，which is consistent with the current tectonic direction. Under the control and influence of canyon topography and faults in the area，the maximum horizontal principal stress orientation of some individual measuring points is NE. The lateral pressure coefficients of the three sections are all greater than 1，which indicates that the area is mainly affected by horizontal compression structure. The lateral pressure coefficients of the three sections with a buried depth less than 300 m，350 m and 500 m are 1.7，2.3 and 3 respectively，which shows that the in-situ geostress of the shallow buried section is also controlled by the topography of high mountains and valleys and the superimposed influence of slope stress field. According to the influence of the angle between the maximum horizontal principal stress direction and the tunnel axis on the stability of surrounding rock，the route layout of Ya¢an—Xinduqiao section of Sichuan—Tibet railway is generally reasonable，although there maybe exist some unfavorable circumstances for surrounding rock stability only at the exit end of Paomashan and Kangding tunnels and the deep buried section of Zheduoshan tunnel(buried depth about 1 000 m). The rock burst of II and III surrounding rock of tunnels is mainly slight and medium，while the hard rock with a large buried depth(more than 870m，1 140 m and 930m in Ya¢an—Luding，Luding—Kangding and Kangding—Xinduqiao sections，respectively) may occur strong rockburst. The large deformation of IV and V surrounding rock presents mainly slight，moderate or strong. Strong deformation may occur for IV surrounding rock with a buried depth more than 1 330 m and V surrounding rock with a buried depth more than 940m in Ya¢an—Luding section，V surrounding rock with a buried depth more than 1 410 m in Luding-Kangding section and V surrounding rock with a buried depth over 960m in Kangding—Xinduqiao section.

In deep underground engineering，the rheological characteristics of rock can affect the construction design and stabilities of engineering structures，which has been extensively investigated. However，the previous studies mainly focused on large inhomogeneous rock samples and ignored the rheological characteristics of minerals in them at the meso-scale. Consequently，in this study，the rheological characteristics and constitutive model of various minerals in sandstone were investigated by using the nanoindentation technique. The distributions of minerals were obtained by using X-ray diffraction(XRD)，scanning electron microscope(SEM) and energy dispersive spectrometer(EDS). The elastic moduli of quartz，albite，calcite and kaolinite from nanoindentation experiment are respectively 87.74，59.85，32.30 and 17.31 GPa，indicating the heterogeneity of the sandstone at the meso-scale. The nanoindentation rheological process consists of instantaneous elastic deformation，creep and elastic aftereffect，which can be described by the Burgess model. During the rheological process，the creep load-holding and unloading periods inevitably make the pores and cracks in the minerals develop，which aggravates the deformation during elastic aftereffect and yields smaller rheological parameters than those obtained from the creep. The macro-scale rheological elastic parameters of sandstone can be obtained by upgrading the rheological elastic parameters of its mineral components at the meso-scale，which provides a convenient and efficient method for studying the rheological properties of sandstone.

With the continuous construction and planning of national road networks，a large number of close parallel or cross railway and highway tunnels has been emerging. Due to the limitations of topography，geological conditions and line strike，the engineering problems of near junction tunnels are more and more complicated. In this paper，taking the 3D crossing Strawberry Channel 1# and Pandaoling Tunnel as examples，especially the Pandaoling Tunnel(underpass tunnel) for the shaking table test，the acceleration and strain dynamic responses of the vault and inverted arch cross-section of ultra-small net spacing and small-angle underpass tunnels affected by the upper-span tunnel were analyzed. Specifically，the maximum seismic strain in the hoop direction was evaluated under the loading condition of 0.15 g peak acceleration of ground motion along the field，and according to the range of the effective frequency accelerometer and the input power spectrum amplitude and using the SPECTE response spectrum analysis program，the distributions of the acceleration response spectrum of the vault and inverted arch at the intersection central were compared. The results show that，affected by the spatial position of the 3D cross tunnel，the acceleration time history and spectrum of the ultra-small net spacing and small angle underpass tunnel are larger than the overall response of the inverted arch，the effective duration of vibration is longer and the spatial distribution is characterized by the prominent amplitude response of the arch. The peak acceleration response of the vault has a superposition effect and the peak acceleration ratio is obviously nonlinear and non-stationary. The higher the earthquake intensity is，the greater the strain response will be. The failure of the vault shows a transfer evolution form from the cross section to the river side then to the mountain side. With increasing the input seismic wave，the increases of the dynamic strain and the peak acceleration ratio of the inverted arch show local changes. The surrounding rock of the tunnel has filtering effect on the high frequency band of the seismic wave. The predominant main frequency markedly influencing the tunnel structure concentrates in two low frequency band of 1﹣10 Hz and 11﹣20 Hz，and the values of the predominant frequency corresponding to the maximum acceleration response of the vault and inverted arch are respectively 5 Hz and 12.5 Hz. For different seismic intensities，the peak strain at the vault are largest，followed by the inverted arch，and the arch waists of the riverside and the mountainside in turn. The predominant frequency of the acceleration response and the responses of the velocity and the displacement are affected by the base frequency and the damping，resulting in difference in time and space. It is suggested that he performance of the damping structure of the tunnel during the design process should be improved and the recommended damping ratio is 20%. The research results can provide certain theoretical guidance for the seismic design of 3D cross tunnels.

The three-dimensional morphology is the key factor affecting the shear mechanical properties of rock joints. 3D scanning is performed to reconstruct the surface morphology model of the sandstone tension joint obtained by the Brazilian splitting test. The stochastic methodology of generating fractal digital elevation models，which is widely used in topography，is introduced to construct surface models with different rough morphological features based on the statistical self-similarity of rough joint surfaces. By adjusting the random parameter d，a series of fractal rough joints with different morphological features are generated using the “diamond-square” algorithm，and compared with the natural sandstone tension joint obtained by the Brazilian splitting test. 3D box-counting method is used to calculate the fractal dimensions of both kinds of joint surfaces，and the statistical distribution of apparent dip angles along a specific shear direction is analyzed. Considering the fractal dimension and the standard deviation of the statistical distribution of apparent dip angles as characterization parameters of 3D joint roughness，it is confirmed that the morphological feature of the natural sandstone tension joint conform to that of the artificial surface with the random parameter d ranging from 2 mm to 3 mm，verifying the feasibility of the stochastic method of constructing digital elevation model based on fractal theory for modelling rough joints with different morphologies.

The influence of crack group on the dynamic mechanical characteristics of surrounding rock is more complex than that of one single-crack. To deeply understanding dynamic failure properties of cracks in surrounding rock mass，several inverted U-shaped model samples with one single-crack or multi-cracks were made of polymethyl methacrylate(PMMA)，and then two sets of impact tests were carried out by using a drop hammer impact testing device to evaluate dynamic fracture behavior under impact loads. The corresponding numerical simulation was performed by employing a modified version of the finite difference method code and a traditional version of the finite element method code. The effects of one single-crack or multi-cracks on crack propagation velocity，dynamic fracture-initiation time and dynamic fracture-initiation toughness under impact loads were discussed，and comparison between experimental and simulation results was carried out. Some significant conclusions were obtained：(1) multi-cracks have an increasing influence on the crack propagation velocity，the crack propagation velocity of a multi-cracks specimen is 1.277 times than that of one single-crack specimen and the dynamic fracture-initiation time decreases with the number of cracks. (2) Compared with the single crack specimen，the dynamic fracture-initiation toughness of the multi-cracks specimen is significantly reduced to 58.72% of that of the single crack specimen. (3) The failure of mixed mode I/II crack is obviously easier than that of pure mode I crack in a same multi-cracks sample and the dynamic fracture-initiation toughness is closely related to the mode II dynamic stress intensity factor.

In order to improve rock crushing efficiency and to reduce energy consumption of ore，the dynamic properties and breakage behaviours of magnetite caused by microwave irradiation with different microwave parameters were studied by using microwave irradiation combined with Hopkinson pressure bar(SHPB). The weakening mechanisms of mechanical properties of magnetite ore by microwave were revealed by the comparative analysis of macroscopic mechanical properties and microscopic structure characteristics. The results show that the influence of the irradiation power on the dynamic performance of magnetite is more significant than that of the irradiation time，and only when the power reaches a certain level will the effect of the irradiation time become gradually significant. With increasing the irradiation power，the damage to the internal structure of the magnetite sample undergo three stages：original crack propagation，intergranular fracture and intergranular fracture accompanied by transgranular fracture，and the slope of the elastic stage of the stress-strain curve gradually decreases with a shorter duration. The yield deformation stage becomes longer，and the post-peak stage presents three phenomena：“strain resilience”，“stress drop” and “post-peak plasticity” respectively. It is concluded that the weakening effect of microwave on P wave velocity and strength is more and more significant with increasing the irradiation power，and the magnetite sample undergo tensile and shear failure stages. It is pointed out that the weakening effect of microwave on the mechanical behaviours of magnetite is attributed to that the different sensibility of magnetite components to microwave results in differential expansion and further leads to intergranular fracture or rupture of granular inner defects. Therefore，when using microwave-assisted rock fragmentation，microwave heating parameters should be designed according to the mineral composition of the rock，the heating characteristics of each mineral and the fragmentation requirements，so as to improve the energy utilization rate and rock fragmentation efficiency of microwave-assisted rock fragmentation.

In the fields of deep energy exploitation and waste storage，permeability is an important indicator. The test method，fluid phase and temperature fluctuation will influence the accurate measurement of the permeability. In this study，the steady-state permeability models based on the inlet/outlet pressure and flow rate were derived and summarized. It was revealed that the results based on the inlet/outlet pressure are quite different while the results based on the inlet/outlet flow rate are relatively close. The reasons for the difference were thereby discussed. In addition，the suggestions for the selection of four steady-state and transient methods were elucidated by comparing the test results of steady-state and transient methods pressure decay. Water，alcohol and gas were selected to investigate the impact of different fluids on permeability test results. It is found that the gas permeability test in low permeability media is sensitive to the temperature fluctuation. To solve this problem，a model based on the temperature fluctuation elimination theory was proposed. Finally，the effects of the confining pressure，the axial pressure，the water saturation and the temperature on permeability evolution were demonstrated and analyzed through the applications in diverse fields，verifying the adaptability of the test theory，method and experimental device. The research work provides a basis for the selections of permeation test methods and  fluid phases.

In the practical engineering of dry hot rock mining，using rock discontinuities as heat exchange channels will reduce the project investment and obtain better engineering effect. In practice，rock discontinuous structural planes in granite mass are usually filled by hydrothermal fluid，forming fracture granite filled with hydrothermal fluid. Therefore，studies on the physical and mechanical properties of fracture granite filled with hydrothermal fluid are of great significance for the construction of artificial reservoir in the actual geothermal development. In this paper，the samples with different structural types are prepared from the later hydrothermal fluid filled fractured granite mass，and at room temperature，P-wave velocity and compressive strength tests on four structural types(up-down structure，left-right structure，parent rock and filling) of granite samples，and tensile strength and permeability tests on five structural types of granite samples(boundary filling，parent rock，filling，left-right structure and boundary parent rock)，were performed. The results show that，at room temperature，P-wave velocity of up-down and left-right structures is the largest，followed by mother rock and filling body，that under 10MPa confining pressure，the average value of the compressive peak strength sc from large to small is up-down structure，left-right structure，filling and parent rock，and that under the same confining pressure，the permeability k of five types of granite samples from maximum to minimum is filling，parent rock，boundary filling，left-right structural granite and boundary parent rock. After hydrothermal filling，the porosity and the permeability at the cementation surface decrease while the P-wave velocity and the compressive strength increase. The parent rock mineral particles at the cementation surface melt and the hydrothermal fluid enters into the fissures or pores of the parent rock in the process of hydrothermal filling，and after the hydrothermal cooling and crystallization，the“adhesion” and “healing” of the cementation surface account for the change of the physical and mechanical properties of the granite at the cementation surface. It is also revealed that，at room temperature，the average value of the tensile strength st of five types of granite samples from high to low is parent rock，boundary parent rock，left-structure，boundary filling and  filling. For the later hydrothermal filled fractured granite mass，the filling is the weakest tensile part of the rock mass，and hence，in the process of geothermal development，artificial fracturing can be carried out on the filling to build artificial reservoir to save the construction cost.

Although the Rankine-based simplified incremental calculation method(SICM) has been widely applied in practice for prediction of nail loads，its model accuracy has not yet fully assessed. In this paper，a large database containing a total of 466 measured nail loads from 178 nails reported in the literature was established. After removing questionable data，the remaining load data from 143 nails were used to evaluate the accuracy of the Rankine SICM，which is characterized by the model bias defined as the ratio of measured to predicted nail loads，and the influence of 3 working conditions on the accuracy of the SICM was also investigated. The results show that，under typical cases，the current Rankine SICM underestimates averagely the maximum nail load by about 10% to 17% with a high prediction dispersion over 90% while overestimates the mean nail load by about 15% with a moderate prediction dispersion of about 70%. In addition，the accuracy is statistically correlated to the magnitude of the predicted value，which is undesirable. It was proposed to estimate the nail load based on the Coulomb active earth pressure theory instead of the Rankine theory for accuracy improvement. A calibration constant of about 0.75 is introduced to calibrate the computed nail load. The Coulomb SICM was demonstrated to be unbiased on average with a medium prediction dispersion from 44% to 66%. It is also shown that the accuracies of both Rankine and Coulomb SICMs are significantly influenced by soil types whereas the influence of load allocation schemes，external loading conditions and wall types is marginal. The model biases of Rankine and Coulomb SICMs respectively follow lognormal and Weibull distributions. Finally，the accuracies of the two types of SICM were discussed complementally from another four angles.

To investigate geotechnical engineering problems such as in-situ soil testing，driven piles and splitting grouting in loess areas，a rigorous semi-analytical solution is derived for drained expansion of a cylindrical cavity under the premise of strict adherence to the definitions of mean effective stress and deviatoric stress，based on the modified Cam-clay model of structured loess. The analytical solutions of the stress and displacement in the elastic zone around the cavity are obtained by using the small deformation theory，and with the aid of the large strain theory and an auxiliary variable，the problem of cavity expansion is transformed into an initial value problem of a system of first-order ordinary differential equations in terms of the Lagrangian scheme in the plastic zone around the cavity. The rigorous semi-analytical solutions of the components of the effective stress and the specific volume are derived based on the elastic-plastic boundary conditions. The results show that the degenerate solutions developed are in good agreement with the existing analytical solutions and the calculation results considering the soil structure are close to in situ test results in the loess area，indicating the rationality of the analysis method and calculation results. The soil structure has a significant effect on the plastic zone radius，the stress component and the specific volume of the plastic zone. The strength of the soil can be increased by taking into account the effects of the soil structure. The degree of softening of the soil can be reduced when the over-consolidation ratio is relatively large. The developed solution can not only provide a reference for the calculation of the lateral resistance of driven piles，splitting grouting pressure and in-situ test parameters，but also provide theoretical verification basis for the simplified calculation of such kind of engineering.

Aiming at that the permeability coefficient of sand drains will gradually decrease in the consolidation process of sand-drained ground，e-lgand e-lglogarithmic models are introduced to describe the nonlinear consolidation characteristics of soils in this paper，and considering the time-dependent well resistance and the variation of the radial permeability coefficient in the smear zone，a governing equation for nonlinear consolidation of sand-drained ground is derived and the corresponding analytical solution is obtained by using the separation variable method. The correctness of the solution is verified by the degradation study and the comparative analysis with the existing analytical solution. Based on the analytical solution，the nonlinear consolidation behaviors of sand-drained ground are investigated. The results show that the consolidation rate of sand-drained ground decreases with increasing the well resistance factor，and the time-dependent well resistance mainly affects the consolidation rate in the later stage. Among the three change modes of the radial permeability coefficient in the smear zone，the parabolic mode has the fastest consolidation rate，followed by the linear mode and then the constant mode. The higher the ratio of the compression index to the permeability index，the slower the consolidation rate of sand-drained ground. Under the nonlinear compression relationship，the average consolidation degree defined by the pore pressure is always slower than the average consolidation degree defined by the settlement in the consolidation process of sand-drained ground.

As one of the common solid wastes，municipal solid waste incineration(MSWI) bottom ash can be mixed with fibers to improve its strength and stability. In this paper，in order to investigate the characteristics of fiber-reinforced bottom ash mixed clay soil under different vertical stresses，different shear displacement amplitudes and different degrees of compaction，large direct shear tests before and after cyclic shear and cyclic shear tests were carried out on the mixture of MSWI-clay-polypropylene fiber at a certain ratio. The test results show that the shear displacement and shear stress curves in the monotonic direct shear tests present weak hardening phenomenon while that the shear stress-displacement curves present obvious softening in the monotonic direct shear tests after cyclic shear. During the cyclic shear process，the soil samples show cyclic shear hardening and shear shrinkage under different vertical stresses and different shear displacement amplitudes. As the number of cycles increases，the degree of hardening and the amount of shear shrinkage gradually decrease. With increasing the degree of compaction，the specimen develops from a clear hardened type to a softened type. The greater the degree of compaction，the less the amount of settlement and the smaller the amount of shear shrinkage. Comparing the results of cyclic monotonic direct shear test after cyclic shear and non-cyclic monotonic direct shear test，it is found that the shear strength of the soil sample after cyclic shear increases significantly，and the cohesion and friction angle increase accordingly. The addition of polypropylene fibers can form a spatial network skeleton with the bottom ash mixed soil，thereby increasing the resistance of the sample against deformation，improving stability and reducing vertical settlement.

Based on the equal strain assumption and nonlinear permeation and compression models，analytical solutions for instantaneously loading，single stage loading and multi-stage loading under combined electroosmosis- vacuum-surcharge preloading，considering the variations of vacuum degree with depth and time，the decrease of additional stress with depth，and the decrease of effective voltage with time，were proposed. The proposed analytical solution was validated by comparing with the experimental and numerical results in the literature，and a parametric study was conducted to investigate the variations of the vacuum degree，the additional stress and the effective voltage with depth and time. The results show that the reduction of the vacuum degree with depth will induce the decrease of the maximum negative pore water pressure and the settlement but has little influence on the consolidation rate. The initial consolidation rate increases nonlinearly with the increase rate of the vacuum degree. The multi-stage loading will effectively decrease the excess pore water pressure induced by loading，which ensures the stability of the soft foundation after loading. The excess pore water pressure and the final settlement will decrease obviously due to the reduction of the additional stress along depth. The larger the residual value of the effective voltage or the smaller the decrease rate of the effective voltage，the larger the maximum average negative pore water pressure and the settlement. Moreover，the consolidation rate decreases nonlinearly with the decrease rate of the effective voltage.