Geological structure form is the intrinsic condition and the controlling factor of water and mud inrush.  The hazard-causing structure of water and mud inrush was classified into 3 categories including 11 types. The first category is karst，including 3 types，i.e.，the corrosion fissure type，the karst cave type and the piping and underground river type. The second category is fault，including the water-enriched fault，the water-conductive fault and the water-resistive fault. The third category is due to the other causes，such as the intrusive-contact type，the interlayer-fracture type，the unconformable-contact type，the differential-weathering type and the special-condition type. 221 cases of typical water and mud inrush disasters were analyzed. The karst category is about 48%，including 105 cases. The fault category is about 29%，including 65 cases. Others are about 23%，including 51 cases. The structural characteristics，occurrence regularity and geological identification methods for different types of water and mud inrush hazard-causing structures are proposed and discussed. In addition，typical case studies are carried out. Finally，four typical hazard modes of water and mud inrush in tunnels are proposed，i.e.，the directly revealed type of water/mud inrush，the progressive failure type of water/mud inrush，the seepage instability type of water/mud inrush and the intermittent failure of water/mud inrush.

In order to study the influence of moisture on the mechanical properties of coal，raw coal and briquette coal samples with different moisture contents were prepared，and the uniaxial compression tests were carried out. Based on the test results，the deformation characteristics of two types of coal samples with various moisture contents were discussed，the relationship between the mechanical parameters and moisture contents of coal samples were analyzed and the failure modes of two coal samples with different moisture contents were compared. The results show that，as the moisture content increases，the width of the compaction phase in the stress-strain curve increases，the width of the elastic phase decreases and the yield phase becomes more visible. The fitting relationships between the moisture content and mechanical parameters of two types of coal samples are the same. The moisture content and the compressive strength have a negative linear relationship，the peak strain and the moisture content have a positive linear relationship，and the elastic modulus and the moisture content have a negative exponential relationship. From the dry state to the saturated water state，the raw coal samples show shear failure and combined tensile-shear failure in turn，while the briquette samples show shear failure，tensile failure and combined tensile-shear failure. The segmented constitutive model of coal mass damage considering moisture content and the stress-strain relationship in the compaction stage of coal was established. The fitting results show that the theoretical curve is consistent with the experimental data.

The quantification of disturbances in deep engineering is a prerequisite to re-understand the causes of disasters. The mechanical parameters of Hoek-Brown and Mohr-Coulomb criteria according to the conventional triaxial compression tests are obtained for the coal at a depth of one thousand meter. Based on the Airey?s solution，a discontinuous stress drop is introduced on the elasto-plastic boundary for the study of continuous- discontinuous transition caused by the plastic failure，highlighting the stress drop and the brittleness index assessment of the abutment pressure. The damage based on the internal friction angle or cohesion degradation is defined to illustrate the discontinuities in plastic zones，and is applied to the discontinuous stress distribution in three various mining layouts including the non-pillar mining，top coal mining and protective coal mining. A new brittleness index is proposed considering the coupled influence of the peak stress，the stress drop，the post-peak modulus and the residual plastic strain，corresponding to the combined effect of external stress disturbances，deformation and mechanical parameters. The qualitative analysis of the strong disturbed zone based on the new definition mainly includes the fracture zone，the post-stress unloading zone，the stress drop zone，the damage zone and the elastic zone. Finally，we proposed a new disturbance index   based on the various mining layouts of  ，the brittleness index  ，the stress drop  and the in-situ stress field  ，and   is strong disturbance.

In mining engineering，the periodic perturbation to rock mass induced by roadway excavation and mining affects the mechanical properties of surrounding rocks. Thus，studying the failure characteristic of raw coal under cyclic loading will help to understand the damage and deterioration mechanism of coal pillar，and to provide the effective means for the analysis of coal pillar instability. In this study，a uniaxial cyclic loading and unloading experiment at different stress levels on raw coal was conducted. Based on the experiment，a load/unload response ratio was defined according to the variation of elastic modulus to describe the failure characteristics of coal. Another response ratio was defined with the accumulative acoustic emission ring counts to describe the evolution of internal damage of coal. A three-dimensional numerical model was established and studied based on the geometric data obtained by CT scanning. The results show that the evolution of the load/unload response ratio of raw coal under uniaxial cyclic loading has three stages，showing a periodic W-shaped variation at each stress level. Moreover，the load/unload response ratio decreases with the increase of loading stress level. It is also found that the load/unload response ratio drops a little bit and then increases suddenly as the loading stress close to the peak stress. However，the load/unload response ratio reaches minimal and fluctuates near 1 as the specimen is on the verge of damage based on the analysis of acoustic emission ring counts.

In order to investigate the dynamic fracturing characteristics of rock under the loading of multiple stress waves，some marble specimens of 160 mm in diameter being pre-cracked chevron notched Brazilian disc (P-CCNBD) were tested diametrically by using the split Hopkinson pressure bar(SHPB) of 100 mm in diameter. The crack initiation and expansion process of specimens were measured with the crack propagation gauge and strain gauge. The dynamic fracturing and energy dissipation characteristics of specimens were analyzed. The results show that P-CCNBD specimens were fractured under loading of multiple stress waves due to 0.13 MPa impact pressure. The energy dissipation in the process of failure under a single stress wave and multiple stress waves were analyzed. The incident energy，reflected energy and dissipative energy of P-CCNBD specimens were reduced with the increasing of the loading times，but the total dissipation energy of P-CCNBD specimens increased with the increasing of loading times. Both the rate of energy dissipation and the dynamic fracture toughness of P-CCNBD specimens decreased with the increasing of loading times and satisfied the linear relationship approximately. Which helps to understand the dynamic fracture mechanism of rock under loading of multiple stress waves.

Traditional theories of wellbore stability have not considered the inertial effects of solid-fluid system and are not suitable for studying the wellbore stability under dynamic loads. In order to analyze the transient variation of the stress field near wellbore and to reveal the poroelastodynamic mechanism during the unloading process，this paper presents a mathematical model based on Biot′s theory of poroelastodynamics to characterize the dynamic behavior of a wellbore in a poroelastic formation subjected to a non-hydrostatic stress field by considering the compressibility of pore fluid and solid grains，the inertial effect and the coupled viscous effect. Through the techniques of mode decomposition，Laplace transform and displacement transform，the analytical solutions of stress components and pore pressure are obtained. The transient behavior of the stress field during the wellbore unloading is analyzed. The results show the importance of the inertial effects of the solid-fluid system，which produces a wave-diffusion behavior in the early times. The higher the unloading rate，the larger the peak of pore pressure and stress. The wellbore pressure has nearly no effect on the peak pore pressure. On the other hand，the higher the wellbore pressure，the larger the peak radial stress and the smaller the peak hoop stress.

The theoretical and technical developments regarding the hydraulic fracturing measurement of rock stress were reviewed firstly. Two hydraulic fracturing methods，including the single drilling pipe based measurement method and the traditional double tubes based hydraulic fracturing method consisting of an externally strapped hydraulic pressure tube and a drilling pipe，were discussed regarding the measurement process features and the application conditions. The wire-line core drilling technique was preferentially used for the geological investigation in the water transfer project at Dianzhong in Yunnan Province，China，due to complicated geological conditions. A new method of hydraulic fracturing measurement of rock stress with double tubes internally installed and sectionally fixed in the wire-line core drilling pipes was proposed to satisfy the special features of the wire-line core drilling technique. The development of corresponding system of equipment operation，the regulation of measurement process and the estimation of possible pressure loss along the hydraulic pressure tubes were studied. Finally，the proposed hydraulic fracturing method was implemented in 5 boreholes with 56 sections of measurement and the maximum depth being 724 m. The measurement technique proposed in this paper resolves the challenging problem that the wire-line pipes cannot be directly used in traditional hydraulic fracturing method，and provides a new technique for rock stress measurement in complicated conditions.  

The strong strata behavior and the corresponding control technology in mining the super-thick coal seam with hard roofs were studied with field test and theoretical analysis to reveal that the mechanism of strong strata behavior and an effective control technology was proposed in this paper. The results show that the breakdown of near field results in a compound periodic weighting in working face，and the instability of far field strata is the main factor that causes a strong strata behavior. The working space experiences stronger strata behavior when it is mined around gob area and under coal pillars because of a more complicated fracture and stress concentration in the high-level hard strata. The architecture of control for the near-far strata with the methods of presplitting underground and hydraulic fracturing in the ground was put forward. Thus，the pressure effects of the hard roofs in near-far field are weakened and the strong strata behavior is effectively controlled. This controlling system presents a new approach to manage the mine pressure.

At present，testing methods for determining the fracture parameters of rock are not consistent，and the test results show the effect of size. Even if the material parameters are given，the corresponding full curve of the fracture prediction of rock materials has not been established. Two key issues that have not yet been satisfactorily resolved，namely，determining the true material parameters(fracture toughness and strength) of rock and predicting the fracture of rock structure，were studied in this paper according to the boundary effect theory. The average grain size of rock was introduced into the modified model of boundary effect，in which the important effect of grain size on fracture was considered. The true material parameters can be determined by using small rock specimens under quasi-brittle fracture control. The complete prediction curve of rock fracture can be constructed using the determined material constants of rocks(fracture toughness and tensile strength) in which the plastic，quasi-brittle，and brittle fractures can be fully described. If the fictitious crack formation is considered or ignored，the minimum size of the rock specimen meeting the requirement of linear elastic fracture mechanics can also be obtained. The tests results from the geometrically similar specimens，non-geometrically similar specimens，and combined specimens that are geometrically similar and non-geometrically similar，were analyzed in detail using the modified model. The rationality of the proposed method for predicting fracture and determining the true material parameters of rocks were confirmed.

Dynamic triaxial cyclic loading-unloading tests on Beishan granite were performed using the rock mechanical test system MTS815. The main objective is to investigate the influence of the volumetric strain ratio on the fatigue characteristics of the rock. For each test，the volumetric strain at the threshold of crack damage stress was identified in the static loading stage. The fatigue initiation and the volumetric strain ratio were subsequently determined by measuring the variation of the volumetric strain for each specimen. The mechanical parameters were further obtained during dynamic loading. Then，the development of fatigue and damage behaviors of the specimens were revealed under different volumetric strain ratios. The instantaneous strains and the maximum plastic strains at failure are found not sensitive to the volumetric strain ratio. With the increasing of loading-unloading cycles，the plastic volumetric deformation presents three characteristic stages. In the stage of uniform deformation rate，the plastic volumetric strain rate and the Young?s modulus decrease nonlinearly with the increase of volumetric strain ratio. The plastic volumetric strain and the Young?s modulus were used to define the damage variables，which describe reasonably the damage process of the tested rock. Moreover，in the steady stage of damage development，the damage velocity of the specimens increases with the increasing of volumetric strain ratio. Different volumetric strain ratios lead to the difference of initial damage for specimens before dynamic fatigue testing. Hence，the fatigue life decreases significantly with the increasing of volumetric strain ratio.

Quantitative calculation of grouting reinforcement effect is essential for grouting design. A new method to accurately compute grouting reinforcement effect was proposed for fracturing-compaction grouting in soft strata. The simplified model of grouting reinforcement effect was established based on the reinforcement mechanism of grouting. The characteristics of grouted body such as anisotropy and spatial distribution were studied. The effect  of related factors on grouting reinforcement was also be analysed. Results show that the grouted body is markedly anisotropic. The grouted body in the direction parallel to grout vein has higher stiffness，higher permeability but lower shear strength than in the direction perpendicular to the grout vein. The cohesive strength and permeability coefficient of grouted body in the direction parallel to grout vein are two aspects of weakness of grouted body. In the grouted region，the modulus of compressibility and cohesive strength decrease linearly along the extension direction of grouted vein. The performance of grouted body is positively related with grouting pressure，and negatively related with the distance of separation between the injection holes. The more grout injected in a hole  results in a better performance of grouted body around injection hole. The proposed calculation method was used in grouting design for reinforcing the sand layer in Qingdao metro line 2 and its effectiveness was confirmed.

A new rheological similar material of soft rock(IBSRO) was developed with the iron ore powder，barites powder and sand as aggregate，the solution of rosin and alcohol as glue，and the hydraulic oil as viscous agent. The effects of components of the similar material on the elastic-plastic parameters and Burger′s model parameters were investigated through orthogonal tests. The test results indicate that the uniaxial compressive strength(?c)，elasticity modulus(E)，Poisson?s ratio(?)，cohesion(c)，viscoelasticity modulus(E1，E2) and coefficient of viscosity(?1，?2) are all affected mainly by the rosin concentration and the content of hydraulic oil. The greater the rosin concentration and the smaller hydraulic oil content，the larger the values of ?c，E，c，E1，E2，?1 and ?2 and the smaller the values of μ. The internal friction angle(?) is mainly affected by the(iron ore powder + barite powder)/ aggregates and the content of hydraulic oil，and the larger the two factors，the smaller the value of ?. The initial creep rate，stable creep rate，primary creep time and rheological strain ratio all decrease with the rosin concentration，and increase with the hydraulic oil content. The range of elastic-plastic and Burger?s model parameters of the similar material corresponds to that of soft rock，which can be used to simulate the instantaneous and rheological properties of soft rock. Finally，the method of determining the ratio of the material components based the multivariate linear regression analysis is presented and is verified in the rheological model test on the shield shaft of soft rock.

Rockburst is a significant challenge to the development of underground space and mining engineering. The prediction of rockburst is an urgent issue need be solved. Based on the one-dimensional cloud theory，a multidimensional cloud model for prediction of rockburst is proposed to deal with the uncertainty in the forecasting process. It regards each prediction index as a one-dimensional variable in a multidimensional cloud model，chooses the reasonable numerical characteristics of each cloud model according to the cloud theory and the classification standard for prediction of rockburst，and determines the weighting coefficient for each prediction index with the improved CRITIC method in view of the information and correlation of the indexes. Thus，the multidimensional cloud models belonging to each rockburst level that synthesizes all prediction indexes are generated and the final rockburst level of rock mass is determined according to the comprehensive certainty with the values of each index input into the models. Then the model proposed in the present paper is validated with the data of 20 groups of typical rock engineering at home and abroad. The predicted results of the proposed model are found to be consistent with the actual rock status and are compared with those from the related method，one-dimensional cloud model and the technique for order preference by similarity to ideal solution combined with rough set (RS-TOPSIS). The results show that the multidimensional cloud model is effective and determines the rockburst level quickly.

This study is to investigate the diffusion mechanism of an ideal self-expansible grout with known density variation over time in rock fracture. Based on the viscous fluid mechanics，a radial diffusion model of the expansible grout in a single water-free fracture is deduced considering the factors such as the initial grout filling range，fracture aperture，time and expansion coefficient. The corresponding axisymmetric model in typical grouting conditions is established with the general CFD software Fluent to verify the analytical model numerically. The numerical results of the grout diffusion radius，pressure and flow velocity distribution are in good agreement with the analytic results at different times under different conditions，which proves the rationality and correctness of the diffusion model.

The similar simulation experiment of coal and gas outburst can reveal the developing mechanism of outburst hazard. The development of an outburst simulating apparatus in middle scale is shown in this paper. The apparatus should adapt to experiments with specific mining environment and operations of presetting experimental conditions is simple and flexible. The outbursts occurred in a certain geological circumstance，such as gas rich area or regional tectonics，can be simulated with the experimental system. The apparatus is composed of a test chamber，a distributed load system，an outburst-inducing device，a vacuum pumping and gas charging system，and a data acquisition system. A geological model with the dimensions of 1 500 mm×600 mm×1 000 mm，containing coal seam，roof and floor and tectonic structure，can be moulded flexibly. The distributed loading on the top face of model simulates the abutment stress in working face. The sieve tube with the diameter of 5 mm is embedded in the coal sample for gas charging. Charging with the graded pressure makes sure that the coal sample reaches the adsorption equilibrium rapidly. A rupture disc installed on the outburst port is used as the outburst-inducing device，and it is destroyed immediately if the gas pressure is over the threshold value. A transparent window on the test chamber shows the fracture process of coal and rock. Data acquisition system collects the most of physical parameters，such as the pressure，temperature and stress. The high-speed photographing captures the movement of outburst coal. An artificial outburst was conducted with absorption equilibrium pressure of 0.30 MPa and inducing pressure of 0.53 MPa. The gas pressure and temperature in the coal sample showed the fluctuating variations because of the adsorption-desorption process during experiment. The duration of the outburst was 1.92 s and 369.9 kg of specimens was expelled from the outburst port. The expelled materials appeared as the fan-shaped distributions and the propagation distance reached 41.4 m.

In this paper，an elastic supporting beam model for powered support groups based on supporting characteristics of powered support is proposed，the stiffness matrix of powered support groups with the method of discrete single span beam is derived，the formulas of deflection of the rock beam and of supporting resistance of hydraulic powered support groups are obtained，the equation of supporting stress field of powered support is established，and a corresponding simplified calculation method is presented. The supporting stress field of powered support in different surrounding strata conditions and structure patterns of powered support are studied and a specific example is described. Finally，the specific conditions of application and direction of development of the theory are put forward.

Formulas of Terzaghi?s ultimate bearing capacity for a strip foundation with different suction distributions were developed based on the unified solution of shear strength for unsaturated soils under plane strain condition. The overall effects of matric suction，four types of suction distribution，intermediate principal stress and roughness of foundation base were taken into account. The formulas were validated through comparison with the model tests，the upper-bound theory and the suction stress method available in the literature. The parametric studies were carried out. It was found that the infiltration depth had an important impact on the bearing capacity of foundations under suction distributions of type I and type II，and the former had four stages while the latter had three stages. The effect of matric suction under uniform suction is more significant than that under other three suction distributions in the low suction range. The dual-effect of high suction makes the bearing capacity to decrease gradually and to stabilize eventually. The effect of high suction under uniform suction is greater than that under linear suction and suction of type II. The bearing capacity of foundations increases with the intermediate principal stress. The strengthening effect of effective strength parameters is obvious. The effect of roughness of foundation base cannot be ignored. Moreover，the difference between the effects of matric suction and roughness of foundation base should be distinguished.

The effects of slope gradient and soil moisture content on the stability of sandy soil slopes were investigated with the geotechnical centrifugal model test，the deformation characteristics and failure modes of sandy soil slopes under centrifugal load were analyzed and the mechanism of water migration influencing the slope stability was discussed. Meanwhile，the test results together and the data from other laboratories in the parallel tests of geotechnical centrifugal modeling that were performed in 2013 were analyzed on the characteristics of error probability of centrifugal model test on sandy soil slopes. It is shown that the deformation of the sandy soil slope presents obvious brittle failure characteristics，and the failure mode features the shallow slippery with a straight linear failure plane. There is a close relationship between the centrifugal acceleration at failure and the slope gradient under the condition of weak water migration. The water migration that exists in sand with high moisture content leads to the remarkable variation of the sand strength，which is the essential factor affecting the stability of the sandy soil slope. The statistical data of centrifugal acceleration at failure present the feature of normal distribution. Notable systematic error is observed in the test process，though the test error is mainly the random one.

泥水平衡盾构在掘进过程中维持开挖面土体稳定的关键在于泥浆性能与地层相匹配。以福州地铁泥水平衡盾构全断面穿越中粗砂层掘进为工程背景，首先分析制浆材料对泥浆性质的影响，并开展泥浆成膜室内试验，采用析因设计综合分析不同泥浆相对密度和黏度下试验的单位滤水量、成膜时间和泥膜形态，以及泥仓压力和含砂率对泥浆成膜的影响。结果表明：在本试验泥浆成膜试验条件下，最终滤水量随着相对密度的增大先减小后增加，随着黏度的增大而减小，同时，黏度对试验最终滤水量的影响小于相对密度的影响；随着泥浆中含砂率的增加，试验最终滤水量先减小后增大；当含砂率为10%～16%时，泥浆成膜最终单位滤水量小，泥浆成膜效果良好；就地取材，将淤泥质土作为泥浆组分之一时，适应福州中粗砂层的泥浆相对密度为1.12～1.18，黏度为26～30 s。

Two 2-year-old shrubs Caragana korshinskii Kom. and Zygophyllum xanthoxylon Maxim.，which were planted in the testing area，were selected as the research objects. The scanning electron microscope (SEM) was applied to analyze the microstructural features of root surface，soil surface contacting the roots and soil surface not in touch with the roots，and to investigate their influence on the friction characteristics of the root-soil interface. The pull-out test of a single root was carried out to quantitatively evaluate the static friction coefficient and the friction resistance per unit area of the root-soil interface of two shrubs. The results of scanning electron microscope reveal that the roughness degree of root surface of C. korshinskii is higher than that of Z. xanthoxylon，that the soil surfaces contacting the roots of both shrubs are relatively flat and dense and that the soil surface not in touch with the roots is rough and porous. The soil surfaces contacting the roots can be flattened by the roots during the growth process so that the roughness degree of the soil surface contacting the roots is significantly reduced，which shows that the friction characteristics of the root-soil interface depend mainly on the roughness degree of the root surface. The results of pull-out test of a single root show that the static friction coefficients of root-soil interface of the roots of C. korshinskii and Z. xanthoxylon are 0.74±0.03 and 0.56±0.04 respectively and that the friction resistances per unit area of root-soil interface of C. korshinskii and Z. xanthoxylon are 22.94±1.15 kPa and  17.26±1.36 kPa respectively，which reflects that the former has a more significant friction resistance per unit area between root and soil.

Boussinesq?s solution is adopted to calculate the additional stress at the tunnel axis caused by ground stack load. It is proposed that compared with the rigid body rotation，the shear dislocation plays a primary role for tunnel deformation modes. The formulas of the longitudinal deformation，dislocation displacement at segment joint，rotation angle at segment joint and shear force at segment joint of the tunnel are deduced according to the principle of minimum potential energy. The calculated results from the proposed method are compared with the data from the elastic foundation beam method and experiment measurement，which validates the proposed method. The effects of the rigid body rotation，shear dislocation，heap load，buried depth and the offset distance of the tunnel on the longitudinal deformation are studied. The deformation of the tunnel under ground stack load is dominated by the mode of shear dislocation. The larger the ratio coefficient j of the rigid body rotation is，the smaller the settlement of the tunnel is. The larger the load is，the larger the longitudinal settlement of the tunnel is，and the range of settlement changes little. The shallower the buried tunnel is，the larger the settlement of the tunnel is. The larger the offset distance is，the smaller the settlement of the tunnel is，and the horizontal displacement of the tunnel increases first and then decreases.

Desert riparian vegetation with rich roots can stabilize the slope and prevent soil erosion effectively. The vegetation of the riverside of Tarim River was studied. Six typical sections in the upper and middle reaches of Tarim River were surveyed. A total of 28 soil samples were obtained，of which 17 samples are root-soil composites including Tamarix ramosissima，Phragmites australis，Glycyrrhiza sp.，Alhagi sparsifolia，Nitraria sibirica and Populus euphratica. The direct shear tests were conducted for root-soil composites of six vegetation roots and soil samples without roots respectively. The cohesion and internal friction angle were compared and the effects of different vegetation roots on shear strength were analyzed. A single root tensile test was conducted for six vegetation types to analyze the relationships between the tensile and shear strengths and the root diameter. The roots were found to enhance the shear strength of the soil through mainly the increasing of the cohesive strength，but had little effect on the internal friction angle. The root-soil composites have cohesions of 9.43 to 28.30 kPa，higher than the rootless soil with values from 3.14 to 16.51 kPa. The tensile strength of root decreases with the increasing of root diameter，while the tensile force increases with the increasing of root diameter. Based on the analysis of mechanical characteristics of root-soil interaction，two models of the root and soil interaction were proposed with the assumptions of rigid and flexible roots respectively，representing the increased maximum and minimum shear strengths. The formulas of the increased maximum and minimum shear strengths with rigid and flexible roots were deduced. The calculated results agreed with the experimental values.