The classification result of surrounding rock quality is important to select the road-header as the tunnel excavation method or not，so the classification method should be proposed. Firstly，a classification standard of surrounding rock quality was presented based on the instantaneous cutting rate(ICR)，which can comprehensively reflect the influence of engineering geological condition and mechanical equipment factors on tunnel milling excavation. Secondly，the influence of the affecting factors and the evaluation indexes，their fuzzy and hierarchical characteristics on the classification result of surrounding rock quality was discussed. Then，a three-stage fuzzy synthetic judgment model of classify surrounding rock quality for tunnel excavation with road-header was suggested，and a method for determining the membership degrees and weight vectors of continuous and discrete evaluation indices was proposed. A corresponding strategy was also proposed to reduce the subjectivity of determining the membership degrees and weight vectors. Finally，the proposed method was applied to three different practical projects，and comparison between the calculation and measured results shows that the proposed method is feasible and reasonable.

Dynamic mechanical parameters of rock mass under earthquake actions are the basis for accurate seismic stability analysis of rock engineering. In the present study，on the basis of exploring the reasonable strain rate of rock materials under earthquake actions，tests and empirical formulas were utilized to investigate the problem of determining the mechanical parameters for igneous rocks considering seismic effect. The results show that，for the relying projects，the corresponding representative strain rate is in the range of 10－2 to 5×10－2/s which is between the quasi-static rate and traditional “medium strain rate”. Fitting analysis of dynamic test results reveals that the intercept of the strength envelope changes with the strain ratio while the shape of the envelope keeps changeless. Consequently，empirical formulas for evaluating dynamic strength parameters were proposed using static parameters and the strain ratio，and a estimating method of rock dynamic modulus under seismic actions was presented based on Hoek & Diederichs equation. The Baihetan hydropower plant project was taken as a study case to illustrate the proposed approach.

Systematic and reasonable statistics of the morphology of rock joints are the precondition for representative sampling of different size discontinuities，which directly impacts the validity of the scale effect test on joint shear strength. To overcome the shortcoming of the traditional uniform mesh statistics segmentation method in terms of different scales of rock joints，a progressive coverage statistical method，taking different size sample as unit sample and extracting the statistical samples of the entire rock joint in orthogonal directions with different step distances was proposed for representing the morphology of various sizes of rock joints. Based on the analysis of the basic characteristics of the proposed method，formulas between the sample capacity，coverage and coverage overlap with the advance distance were proposed. Case study shows that，with the propulsion of the unit sample，the sample overlap and a more complete unit sample can be obtained，which covers partial missing area morphology，increases the sample size and improves the accuracy of the whole sample. The progressive undulating morphology of series scale rock joints can be entirely derived by this method，which provides the sampling basis for various size samples.

In order to study the dynamic fracture characteristics and the effect of stratifications on crack porpagation behaviors in shale，the dynamic loading experiments with split Hopkinson pressure bar(SHPB) equipment were conducted on single cleavage triangle(SCT) shale specimens with different inclinations of 0°，30°，45°，60° and 90°，and the crack propagation process was simulated adopting the dynamic numerical analysis code AUTODYN by regarding shale as a composite layered material. The results show that stratifications significantly affect the crack propagation direction and the fracture morphology of the specimens. It is also revealed that the crack propagation speed correlates positively with the loading speed as a whole while that crack deceleration is likely to occur when the loading speed is lower. Cracking along the stratification plane is the main failure mode of layered rocks such as shale，but the generation of secondary cracks is not completely random. It is also found that the region of crack deceleration usually has a high probability of secondary crack initiation.

The fracture and disaster-causing mechanism of high-speed and long run-out landslides is one difficulty of landslide disasters. In order to deeply study the dynamic process of landslides from continuum to discontinuum，a cohesive fracture model is proposed based on block discrete element method. High-performance parallel computing based on graphics processor unit(GPU) is achieved， and a coupling simulation platform called couping discrete element method platform(CoDEM) is developed. Taking Yigong landslide as an example，the whole process of higher body collapsing，old landslide body resurrecting，debris flowing at a high speed and dam forming is studied systematically. Comparison between the numerical results and in-situ survey data is performed.It is shown that the numerical results including accumulation boundary and material components are in good agreement with the actual situation of the landslide. According to the dynamics characteristics during the landslide at different stages，the landslide area can be divided into four parts such as the initiation zone，the buffer zone，the circulation zone and the braking zone.

 P-wave and S-wave velocities are important parameters for studying shale anisotropy. In order to study the influence of the laminae direction on P-wave and S-wave velocities and dynamic elastic parameters，the Mesozoic and Cenozoic lacustrine shale in the eastern part of China was used as the research object，and P-wave and S-wave velocities experiments were carried out on the coring samples with different laminae directions. The results show that the ratio of P-wave and S-wave velocities has no correlation with the laminae direction，which is caused by the main extension direction of microcracks. The smaller the angle between the P-wave or S-wave propagation direction and the laminae direction，the greater the P-wave or S-wave velocity is. The P-wave and S-wave velocities in different laminae directions are always linearly correlated with each other. The slope and intercept of the linear curve are respectively related to the laminae interface and microcracks. The dynamic elastic modulus and the laminae direction have a good correlation，which is mainly affected by the laminae interface，while the dynamic Poisson?s ratio is independent of the laminae direction，which is mainly affected by microcracks.

An indirect boundary element method for solving the dynamic response of slopes in layered half-space was proposed，and the influence of geometric parameters and elastic modulus on seismic effect of rock slopes was studied. The method simulates the scattered wave field generated by the slope topography by applying inclined and horizontal fictitious distributed loads on corresponding boundaries，avoiding the singularity problem in the conventional boundary element method and thus obtaining higher calculation accuracy and faster solution speed. The correctness and convergence of the developed method were analyzed，and the corresponding numerical calculations were carried out. Results show that the seismic dynamic response of rock slopes has significant elevation amplification effect，i. e.，the peak acceleration(PGA) amplification factor of the slope surface increases nonlinearly with increasing the relative elevation and the horizontal acceleration response is greater than the vertical. The ratios of the horizontal amplification factor to the vertical respectively corresponding to soft rock and hard rock can reach 1.51 and 1.14 in the calculation examples. The geometric parameters and elastic modulus of the slope have important influence on the dynamic response of the top of the slope. The PGA amplification factor increases with increasing the angle and height of the slope while attenuates with rising the elastic modulus. Comparisons indicate that the amplification factor calculated by the Code for Seismic Design of Buildings (GB50011—2010) does not take into account the influence of lithology and at the same time underestimates the topographic effect to some extent. According to the analysis results with different input seismic waves，an empirical formula for evaluating the dynamic response of the rock slope with the changes of geometric parameters and elastic modulus was proposed，which facilitates the quantitative description of research results. By analyzing the Fourier spectrum characteristics(of rock slopes such as peak value，shape and predominant frequency)，the spectrum law of dynamic response at the top with changing geometric parameters and elastic modulus was obtained，and then the spectral ratio curve was introduced to quantitatively evaluate the spectral amplification effect of ground motion with different angles，heights and shear wave velocities.

In order to study the influence of the crack length and the bedding angle on the characteristics of modes I and II fracture of coal，the specimens with three kinds of crack lengths and five kinds of bedding angles were tested by using the semi-circular bending test method. The influence of the crack length and the bedding angle on the peak load，the fracture toughness and the crack propagation path of modes I and II fracture were analyzed. The acoustic emission signals were monitored and the microcrack damage evolution and macroscopic failure characteristics were obtained. The experimental results indicate that the peak load and the fracture toughness of model II fracture of bituminous coal are respectively greater than those of mode I fracture and KIIC/KIC equals to 1.02. With increasing the dimensionless crack length α，the peak loads of both modes I and II of coal decrease gradually while both KIC and KIIC increase first and then decrease. Both the peak load and the fracture toughness of model II decrease first and increase in a “check” pattern with rising the bedding angle. The crack propagation paths of modes I and II fracture of coal are respectively linear and nonlinear. Beddings have a great influence on the crack growth path of mode II fracture，and the crack propagates along the bedding plane as the bedding angle is 22.5°，45°or 90°. The fracture failure process of modes I and II fracture can be classified to be three stages as compaction，steady crack propagation and unsteady crack propagation. In general，modes I and II fracture present a mixed tensile-shear behavior dominated by tensile cracks. More specifically，the tensile microcracks develop first，then the tensile and shear composite microcracks expand extremely and finally failure occurs.

To investigate rock mechanical properties under high temperature and stress coupling，which is one of the research hotspots in the field of deep resource exploitation，a real-time high-temperature true triaxial test system was developed. The system，mainly composed of three subsystems including rigidity mechanical loading system，high temperature control system and servo control and data acquisition system，can realistically simulate the thermal-stress coupling environment of deep rock masses and perform various stress paths such as uniaxial，conventional triaxial，true triaxial，creep，cyclic loading and unloading with a standard rock sample of 50 mm×50 mm×100mm at a highest rock sample surface temperature of 460 ℃. The maximum loads of three loading directions(?1，?2，?3) which can be independently controlled are respectively 1 000 MPa，200 MPa and 200 MPa. The high temperature control system consists of a six-circuit detachable flexible heating element and an aerogel insulation cover，of which each circuit is separately monitored by the temperature control box to realize real-time heating and monitoring of rock samples. Thermoplastic mold steel and water-cooled circulation system is used to ensure the overall rigidity and working stability of the test system at a high temperature，and high-precision closed-loop servo control system with magnetic displacement sensors can accurately monitor displacement and pressure in three directions for multiple stress path tests at a high temperature in real time. High temperature in real time true triaxial tests were conducted and the effect of temperature and intermediate principal stress(?2) on mechanical properties of granite were studied. It is shown that 400 ℃ temperature can enhance the strength and elastic modulus of granite and that the intermediate principal stress(?2) can enhance the strength and peak strain of granite at 400 ℃ temperature. Meanwhile，the intermediate principal stress(?2) can enhance the strength but decrease the peak strain in the third main stress direction of granite at RT. The reliability and stability of the high temperature in real time true triaxial test system were verified by comparing the test results by the developed system and the conventional triaxial test system，and the research results can provide theoretical and technical supports for the development and utilization of dry hot rock resources，nuclear waste repository construction and deep rock mass engineering.

To study the seepage and dissolution coupling mechanisms of rough rock fractures，the pricewise linear method is adopted to generate the fracture surface and the fractal dimension is utilized to characterize the roughness. A lattice Boltzmann model，applying the double distribution function to respectively simulate the evolutions of velocity field and concentration field and assuming that the dissolution at the fracture surface satisfies the first-order dynamic reaction model，is proposed to simulate the coupling mechanism considering the effect of surface reaction. The validity of the proposed model is verified by two classical examples，and the effects of the fractal dimension，Pe number and Da number on the seepage and dissolution coupling mechanism of rough fractures are discussed. The results show that the larger the fractal dimension is，the slower the solute transport is，which results in a slower dissolution rate at the fracture surface. The dissolution occurs preferentially at the raised position of fractures，which makes the surface smooth gradually. When the Pe number is larger，the seepage velocity is relatively higher，which promotes the solute transport and the dissolution reaction，causes the surface geometry flattening and increases the permeability. The larger the Da number is，the faster the dissolution rate at the entrance is，which leads to more undissolved parts accumulated at the end of the fracture when the porosity is the same and affects the permeability of the fracture.

A calculation formula for the radial displacement of surrounding rock was derived according to the convergence analysis of linear elasticity of surrounding rock，and a solving method of the support resistance of shotcrete lining and rockbolts was determined based on the thin-wall cylinder theory and the point anchored reinforcement theory. Performance functions involving excavation of the surrounding rock as well as rockbolt- shotcrete support were deduced. Aiming at the problem that the common second order reliability method(SORM) could not be applied directly due to that the performance functions were highly nonlinear and implicit，a calculation formula of gradient vectors，instead of the analytical algorithm used in common SORM，was deduced based on the difference principle，and a direct calculation method for stability reliability of tunneling structure，which is free from the constraint of the performance function form，was proposed. A tunnel project was analyzed by the developed method，and comparison between the calculation results by the method and Monte-Carlo method was performed. It is shown that the developed method is widely applicable and accurate. Meanwhile，a suitable step length coefficient v = 0.01 which has universally applicable meaning in the independent standard normal space was suggested.

Dimensional discrete fracture network(DFN) is a common approach to analyze the structure of rock masses. However，Baecher disk method which is most popular，is entirely based on statistics and the assumption that fractures are disks rather than polygons for the convenience of mathematical derivation. In this study，a polygonal DFN modeling method more really reflecting fracture feature was developed to improve the traditional Baecher disk method. A circle-controlled method was proposed to determine the shape of random polygonal fractures and its validity was proven through mathematical derivation. For determining the size distribution of fractures，an iterative inversion algorithm was presented. To ensure that the algorithm is able to rapidly converge，a set of adjusting and initialization rules of the parameters of the algorithm were designed. A case study，in which comparison between the trace maps of two DFNs generated by the proposed method and Baecher method is carried out，shows that the iterative inversion algorithm can almost achieve the same results as Baecher method when assuming that the fractures are disks. Further，a polygonal discrete fracture network is generated using the presented method. This research provides a new way to analyze the structure of rock masses.

In coal mining，hard roof collapse control of steeply dipping coal seams is a challenging problem，and hence，investigations of the collapse mechanism and control method of the hard roof in steeply dipping coal seams are crucial to coal mine safety production. In this study，the mechanical properties of coal-rock strata were analyzed through field investigations and indoor tests，and the collapse mechanisms，characteristics and range of the hard roof in steeply dipping coal seams were exploited by indoor similar material simulation experiments and discrete element numerical calculations. A presplitting blasting scheme of the hard roof was designed，and the collapse control scheme of the hard roof was simulated using the discrete element method and compared with the actual application. The results show that the rock stratum of the hard roof exhibits visible elastic-brittle-plastic failure characteristics and that the elastic-brittle-strain softening constitutive model used to evaluate the failure process of the coal-rock contact surface can reasonably reflect the failure characteristics of the steeply dipping coal seam roof. The results of both 3DEC simulations and similar material simulation experiments reveal that the steeply dipping hard roof deforms inconspicuously along the trend and is not easy to collapse along the strike under the short-wall mining condition，and that it is easy to form a large-area suspended roof with a span of 75–85 m in the rear goaf accompanied by obvious sudden collapse. A numerical calculation approach for calculating the advanced deep hole presplitting blasting roof was proposed based on the discrete element method，and the comparison between the simulation results with the actual application results validates the feasibility of applying this method to hard roof control.

In coalbed methane(CBM) reservoirs，relative permeability curves are commonly obtained using gas-water displacement experiment，and it is commonly concluded that the 2-phase flow area is very narrow and that the critical water saturation is extremely high according to experimental results. However，the fluid flow in coal is a complex process of coupled desorption from matrix and 2-phase flow in cleats. The process that gas desorbs from matrix，enters cleats and displaces water is different from one-direction gas displacement in laboratory，which leads to that the sweeping efficiency in production process is higher than that in experiment. To obtain the appropriate relative permeability in coal，a CBM productivity model was established in pseudo-steady state considering the desorption effect in matrix. Combining the material balance equation，an inversion method of the relative permeability curve in CBM reservoirs was proposed based on production history. The difference between relative permeability curves obtained from experiment and the developed method was discussed，and it is pointed out that the difference contributes to the low sweeping efficiency in experiment. Finally，the effects of two types of relative permeability curves were illustrated using numerical simulation method.

Stochastic calculations，by combining the random field theory and the finite difference analysis together with Monte Carlo simulation，are used to carry out the sensitivity analysis of spatial variability of soil parameters to surrounding-soil response induced by tunneling. The effects of coefficients of variation(COV) of Young?s modulus(E)，Poisson?s ratio( )，cohesion(c) and friction angle( ) on the surrounding-soil response were investigated and discussed in detail. Results show that the main influence factors on surrounding-soil response are arranged in the order of spatial variability of internal friction angle，Young?s modulus，cohesion and Poisson?s ratio. The higher the variation level of the parameters，the greater the sensitivity of the parameters. Additionally，the influence of spatial variability of Poisson?s ratio on surrounding-soil response can be neglected in stochastic analysis. The influence of cohesion can be considered comprehensively according to the variation level.

Based on the piecewise linear difference method，a new model of simulating the large strain consolidation of soft clay under the combination of electroomosis and vacuum preloading was developed. The model considers soil nonlinearity and was implemented using FORTRAN. The model was validated by the small strain analytical approach and large strain experiment. The modelling results agree with the analytical solutions and the experimental results. A parametric study was conducted to examine the effects of different combinations of vacuum preloading and electroosmosis. The results show that the combined method outperformed the single-process method. The final average settlements of the soil under varied combinations of vacuum preloading and electroosmosis are approximate. The process of applying the electric field after the surcharge preloading can reduce energy consumption. Further energy reduction can be obtained by confining the degree of consolidation within 80%.

In order to comprehensively assess the cooling effect of the crushed rock embankment on permafrost，different embankments such as the open-system crushed rock thickened revetment，the closed-system crushed rock revetment，the open-system and closed-system crushed rock basement and the U-shaped crushed rock embankments in the Beiluhe test section of the Qinghai—Tibet Railway were investigated. Selecting thirteen factors as the bottom evaluation indices from internal and external factors of permafrost，the cooling effect of the crushed rock embankment was evaluated by catastrophe progression method，and a comprehensive evaluation model which consists of four hierarchical structures was proposed. The results show that the evaluation results are basically line with the measured results and the calculated results can accurately reflect the strength of the cooling effect of the crushed rock embankment. The thickened revetment of the crushed rock slope is susceptible to the thermal disturbance of the engineering at the initial operation period of the engineering measures and presents a weak cooling effect. When the change of the ground temperature reaches a relatively stable state，the cooling effect shows different due to the different cooling mechanisms of different crushed rock embankments. The U-shaped crushed rock embankment with an evaluation value more than 0.97 has strongest cooling effect，in turn followed by the open-system crushed rock basement embankment，the closed-system crushed rock basement embankment，the crushed rock thickened revetment and the closed-system crushed rock revetment.

为研究地表交通荷载引起邻近浅埋隧道振动问题，建立地表移动荷载下三维弹性半空间中隧道振动分析模型。隧道衬砌模拟为中空圆柱体，隧道周围土体模拟为含有圆柱形空腔的黏弹性半空间。地表车辆荷载简化为4个均布矩形荷载，矩形荷载可以分解为关于隧道轴线正对称和反对称2种荷载分量。含有圆柱形孔洞的地基中位移场分解为下行平面波引起的位移场和外行圆柱波引起的位移场，通过波场转换可对地表和衬砌–土体接触处的边界条件进行描述，在频域中获得控制方程基本解，然后利用快速Fourier变换获得时域结果求得。地表车辆荷载下邻近隧道的振动响应可由正对称和反对称荷载工况下的结果叠加得到。计算结果表明：隧道两侧车辆荷载在隧道处引起径向动应力最大值分布在以竖向为中心的－45°～45°范围；增加隧道埋深或车辆距隧道的水平距离，可显著减小隧道的振动速度响应和应力响应；一定隧道埋深下，车辆荷载与浅埋隧道的水平距离达到最小安全距离时隧道振动可以满足相关振动规范的要求，且该安全距离跟车辆速度在研究范围内呈线性关系。

In this paper，a novel technology of the vertical steel floral tube micropiles with twice grouting was proposed，and，based on large-scale model tank tests，the slope soil pressure，horizontal bearing capacity and flexural performance of the micropile were investigated in cases of no pile，a single pile with traditional one grouting，a single pile with twice grouting and three piles with twice grouting. The experimental results show that the fracturing pressure of the twice grouting is directly related to the interval time between the first grouting and the secondary grouting. The longer the interval time，the greater the fracturing pressure is. Compared with traditional one grouting，the horizontal bearing capacity of the twice grouting floral tube micropile increases by 24.42%. Compared with the 3-fold value of the horizontal sliding resistance，the horizontal bearing capacity of the structure with three micropiles is 20.25% higher. The force bearing point of the micropile against the landslide thrust moves down due to twice grouting，which improves the action mode of the landslide thrust. Test results show that the ultimate bending moment and bending resistance capacity of a single pile  respectively increase by 12.8 kN•m and 96.2% with twice grouting. The technology significantly improves the horizontal bearing capacity of the steel floral tube micropile，enhances the soil reinforcement performance between piles and increases the shear capacity and flexural capacity of the micropile compared with the original technology.

Water is one of the most important factors causing surface erosion of earthen sites. In this study，microbially induced carbonate precipitation(MICP) technique was used to form a water-resistant layer on the surface of tabia，and the applicability of MICP for tabia surface erosion control was examined by the static contact angle test，capillary water absorption test，Karsten tube test，durability test，acid resistance test，water vapor permeability test and surface color change test in the laboratory. The effect of the concentration of bacteria and cementation solution on the surface erosion control was analyzed. The test results show that MICP can significantly improve the water resistance of soil samples by changing the microstructure of the surface. A higher concentration of bacteria and cementation solution can make the sediment layer play a better protection in a non-linear form. There is a suitable concentration value of the bacterial solution. When the bacterial concentration is less than the value，the change of the concentration has a great influence on the water resistance of the treated samples. However，the change of the bacterial concentration greater than the value has no obvious effect. The discovery of suitable concentration value can improve the economics of MICP technology on the premise of successful application of MICP in practice. The MICP protection layer not only has good durability，but also has little negative impact on the air permeability and color of the samples. MICP can be used as an effective method to relieve surface erosion of earthen sites.