A bulky mining-out area was formed at Dahongshan iron mine with sublevel caving method. The thickness of overburden is 627 to 750 meter. In order to understand the development of collapse area，fractured zone and high stress concentration zone in overburden so as to prevent the sudden large-scale and dynamic ground pressure disasters，micro-seismic monitoring，tunnel observation and borehole detection methods were used to carry out the comprehensive monitoring and research. Base on the precise location of fracture source with multi-channel micro-seismic monitoring technology，high-stress concentration zone and its developing trend were determined，and then the outer boundary was deduced. At same time，the analysis on fracture types of fracture source with double couples model showed that the tension fracture with volume-increasing accounted for majority of all sources，while the shear failure and mixed failure accounted for minority. The boundary of collapse area，external and internal boundaries of fractured area were determined directly through the artificial observation in special tunnels. The borehole detection as the auxiliary method was used to determine and validate the external boundary of fractured zone. A comprehensive monitoring and analysis were carried out to obtain the caving zone，cracking zone and high stress concentration area in overburden in different periods from 2011 to 2013. The development of high stress zone，cracking zone and caving zone in different periods were also obtained. The studies showed that the caving and cracking processes in overburden were slow and gradual. The sudden and dynamic large-scale collapse disaster would not occur. The conclusion of this paper played an important role in guiding the safe production of the mine.

The study on the strength parameters of deep rock mass is complicated and difficult. The strength parameters have close relationships with the sample sizes，stress states and loading paths. A series of triaxial tests are carried out to study the strength parameters and their variations characteristics of T2b marbles from the deeply located intake tunnel of Jinping II Hydropower Station，including the loading and unloading triaxial tests of different size samples in laboratory and in situ with low-middle，middle-high and high-very high confining stresses. Following results can be noted. Firstly，test results of ten sets of different kinds of mentioned triaxial tests on the strength parameters are listed in the paper as to show the effects of confining stress magnitude，stress loading and unloading path，and sample size on strength characteristics. Secondly，the variation characteristics of the strength parameters of T2b marbles show a consistent variation tendency when the confining stress magnitude changed：the value of   decreases and the value of c increases with increase of confining stress magnitude，but the ranges of variation of the  and c values are not in consistency with different loading paths and different sample sizes. Thirdly，compared to loading condition，the unloading path will lead to a higher value of the strength parameter  and a lower value of parameter c. At last，The size effect of the strength parameter of the marbles in the scale from  50 mm×100 mm to 500 mm×500 mm×1 000 mm is not obvious，but the size effect of the strength parameter c is significant.

To inverse mining-induced stress field，a research program was conducted at the Laohutai mine. A solution of rock rupture in seismology was applied to solve the focal mechanisms of 81 large seismic events observed in the mine field. Combined with field investigation and in-situ stress measurement，the evolution of the principal stress field in the mine field was analyzed. It was found that the principal stress was not uniform due to the influence of fault and different mining sequences and various zones were identified. Compared with the original in-situ stress field， the orientation of the minimum mining-induced principal stress changed from roughly horizontal to near vertical. Under the influence of mining-induced stress，a normal fault in deep levels not only became a fluid storage body and flow path but also was activated and changed into a thrust fault，potentially to release a large amount of seismic energy. The focal solution is useful for studying the pillar instability，roof caving，and normal fault thrust catastrophe，thrust fault activation. It was seen that for mines equipped with microseismic monitoring system，tracking and inversing rock mass fracture source mechanism during mining can detect potentially the fault activation at an early stage and thus precaution can be taken promptly.

Microseismic and acoustic emission(AE) monitoring during rock fracture process have been widely applied in the area of rock engineering. Automated P-onset picking is a fundamental and key link of location and moment tensor inversion in AE technique. The identification sensitivities regarding the jumping of the amplitude，frequency and phase of the analog signal waveform with the Allen picker，the Baer-Kradolfer picker，the Higher Order Statistic picker and the AR-AIC picker were analyzed for improving the picking accuracy. A comparison of P-onset picking for different signal to noise(SNR) levels by different methods was carried out based on the field monitoring data from the Tunnel Sealing Experiment in Atomic Energy of Canada Limited?s Underground Research Laboratory(URL). The result showed that the Allen picker，the Baer-Kradolfer picker and the Higher Order Statistic picker had a wider scope of SNR identification and better identification ability especially for AE signals at low SNR level. Thus，an improvement for the AR-AIC picker was proposed. The key factors affecting the picking accuracy were discussed and the reasonable parameters applied to AE signals were gained when picking P-onset of real signal waveforms using the improved AR-AIC picker. The P-onset was successfully picked when using the improved AR-AIC picker on AE signals with SNR level below 10，and it indicated that the Kurtosis method was the best picker during the preliminary P-onset detection stage. Comparisons of the results of automatic and manual identification showed that the accuracy rate reached 94% with a time lag less than 5 ?s. The improved AR-AIC picker shows good feasibility in practical application especially for AE signals in low SNR level.

Water inrush is a common geological disaster in tunnel construction in completely weathered granite soil，and the loss of soil particles and the anti-scouring property are the keys to determine the water inrush. Therefore，a simple device for grouted sample manufacturing and an anti-erosion device were made to manufacture the samples of compaction grouting and fracturing grouting and to simulate the vital process of grouting reinforced solid being flushed by the flowing water. With these devices，a series of tests were carried out by controlling a number of factors such as the grouting capacity，the velocity of dynamic water，the curing time and the initial water content of the soil. The index of the particle erosion rate(PER) was proposed to evaluate the loss of soil particles and the anti-scouring property. The test results showed that the anti-scouring property was improved with the increasing of grouting capacity and curing time. However，the particle erosion rate was increased significantly with the increasing of dynamic water velocity，and the anti-scouring property was poor when the initial soil water content was very low or very high. There existed an optimum initial water content to make the anti-scouring property the best. The range of grout cementation over grouting capacity(ratio of grouting cementation) changed parabolically with the grouting capacity. The peak of grouting cementation ratio moved to the direction of high grouting capacity with the increasing of water velocity. A new method to calculate the grouting capacity and the principal of partition treatment of water inrush was proposed according to the test results.

To study the propagation behaviours of rock avalanche along 3D complex topography quantitatively，a 3D analogue model was built based on the true topography of the Xiejiadianzi rock avalanche. A series of experimental tests were conducted to document the propagation and deposit features of rock avalanche under the effect of 3D complex topography. Along the travelling path，the layout of complex terrains such as the twisted spots generated the rapid dissipation of the kinetic energy of rock avalanche，and reduced the travel distance finally. In the motion of rock avalanche，the existence of momentum transfer among particles played an important role in the long runout of the debris. The extension of small ramps along the both sides of the traveling path induced the shunting-converging movement of the debris，with longitudinal groove-like troughs formed finally. When the debris reached the open area of the travelling path，it transferred into an unconfined spreading movement with particle collisions occurred frequently. Under the co-work of the pushing force，gravity and topography，squeezing effect occurred in the motion of particles with stress ridges generated.

The failure of rock bridge in rock slopes is an important factor for the instability of a slope. The triaxial loading，triaxial loading-unloading and triaxial unloading tests of different length of rock bridges were carried out. Acoustic emission(AE) characteristics of rock bridge during failure process under different stress paths was described，and the influence of confining pressure and rock bridge length on the AE characteristics was analyzed. The results showed that AE events are low during the compression and elastic deformation phase. AE events increased significantly during the plastic phase，and AE counts，the accumulated energy and amplitude reached their peak during failure phase. Significant changes in AE characteristics can be used as early warning for failure of rock sample， the variation of amplitude is more sensitive than other AE indicators. Therefore the monitoring of the amplitude is more effective for the failure warning. In this experiment the rock bridge is not immediately dropped to the residual strength after the peak strength，but two stress drop occurred after peak stress，each sudden drop of stress corresponds to the AE signal peaks. The phenomenon of“quiet period”or“post-peak rebound”occurred in the two stress drop，and AE characteristics of the“post-peak rebound”and“quiet period”is similar to the plastic phase. However，its amplitude，count rate and the accumulated energy are greater than plastic deformation stage which indicates the rock crack is still in a relatively rapid rate expansion，and resulting in the failure of rock bridge. Accumulated energy from the large to small are triaxial loading-unloading，triaxial unloading and triaxial loading under different stress paths. With the increase of length of rock bridges and confining pressure AE count rate peak and cumulative energy increased，and meaning more severe failure of rock bridge.

Currently，the mineral component and anisotropic microstructure of the low-rank coal are lack of systematically quantitative research. The scanning electron microscope(SEM) test and mercury test were carried out to analyze the anisotropic characteristics of the morphology and distribution of microcracks. The microscopic images were processed into the binary digital images of minerals and micro-cracks with the appropriate gray threshold. The mineral percentage in coal，the volumetric percentage of microcracks in parallel directions and perpendicular directions of the beddings were calculated. The box fractal dimension of micro-cracks that parallel to and perpendicular to bedding seam scanned by SEM were calculated based on the fractal theory，according to which the micro cracks perpendicular to bedding microstructure is relatively smooth and irregular. According to the mercury test to coal samples，the total volume of injected mercury changes with pressure，the apertures of coal samples were mostly distributed in 10–100 nm or 15–95 ?m，and the largest specific surface area for microcrack is around 10–100 nm. The pore distribution of coal explant lamellar structure and mineral floc structure by SEM also around 10–100 nm. It indicates that the explant lamellar structure and minerals flocculent structure of coal could provide a larger specific surface area and the coal explant could have very strong adsorption capacity of coal bed methane(CBM).

Studies on the influence of blast-created free face on ground vibration in slope blasts with millisecond-delays are very significant for optimization and safety control in blasting excavation. A multiple-row bench blast test at Baihetan Hydropower Station was conducted to compare the blast-induced ground vibration from the first and followed delay in the same row. A SPH-FEM coupled model was also developed to simulate the fragmentation process and the blasting vibrations from different delays in the same row. The simulated results agreed well with the experiment results. If the charge weight and the blasting geometry parameters were the same in each blast delay，the ground vibration induced by the first delay will be larger than that of the followed one. The study indicated that the effect of the blast-created free face should be considered in the blasting design. From the perspective of vibration control，the charge weight of the first delay in every row should be less than that of the followed delays in the same row.

 There are two problems in processing the subsidence data due to mining，one is the complication of the procedure to calculate the movement and deformation in the main sectional plane，the other is lack of the robust method for parameter calculation. A modified model was put forward to calculate movement and deformation in the main sectional plane based on the coordinate system conversion. A robust inversion method with the probability integral was proposed based on the principle of minimum-quadratic residual sum of moving vector，the uniform design of parameters initialized samples，Chauvenet detection of abnormal samples and the weighted pure samples. The simulated experimental results showed that the robust method for parameter calculation can also invert the precise probability integral parameters，even if the initial sample of parameters with large span (partial sample parameters gravely deviates from the true value).

To investigate the effect of anchorage support on zonal disintegration in deep tunnel excavated by drilling and blasting method，three dimensional physical model experiment under high axial geo-stress and blasting excavation conditions was carried out by deep rock breakage and supporting technique model test apparatus. After blasting excavation and overload in axial direction，both radial tensile strain and radial compressive stress around anchored model tunnel presented a non-monotonic change of distribution with peaks and troughs，which is similar to the model experiment results without the anchorage support. The results indicate a tendency of inducing zonal disintegration in anchorage model tunnel. Compared with the model experiment results without anchorage support，there is no zonal disintegration phenomenon in anchorage positions of model tunnel supported by combination of anchor bolt and anchor cable. Therefore，combination of anchor bolt and anchor cable can transfer and redistribute the stress of surrounding rock. Hence，anchorage support plays an important role in restraining the zonal disintegration.

Gas desorption of coal under different hydrostatic pressures in closed environment was studied based on the servo-controlled seepage equipment for thermal-hydrological- mechanical coupling of coal developed in-house. The variation of the gas desorption pressure in the confined environment was analyzed with the state equation of ideal gas as a bridge. With the increase of hydrostatic pressure，the pressure of gas in the closed system increases by 0.277%–0.750%. There are two parts in the change of gas pressure( )：the change of the gas pressure caused by the spatial change of porosity and fracture caused by the stress loading( ) and the change of the gas pressure caused by the gas desorption( ). With the increase of hydrostatic pressure，the proportion of   decreases，and the proportion of gas desorption pressure in coal increases. As a result，the coal and gas outburst and other dynamic disasters are more prone to occur.

In order to study the seismic response of loess-mudstone slopes，centrifuge shaking table tests with the geometric scale of 1∶40 for two types of model slopes based on the prototype slopes in Tianshui area were performed. Under the condition of similitude，the seismic responses of model slopes were investigated with the input seismic waves of different amplitudes horizontally and vertically. The input acceleration amplitude of 0.1 g was taken as the typical example and the different dynamic response and failure characteristics of the two model slopes were analyzed. At the key point in both models，the horizontal peak ground acceleration(PGA) amplification coefficients are larger than the vertical ones with nonlinearity，and reflect the surface effect，the altitude effect and the lithology effect. For the failure of the general loess-mudstone slope，tension cracks were formed at the crest and gradually expanded. The displacements developed towards the free face，and then overlying loess raised slightly and some soil mass accumulated at the slope toe. For the loess-mudstone landslide，the tensile crack formed at the backscarp and gradually expanded and then collapsed. The landslide debris fell slightly. A groove was formed at the top of the debris，and the slope toe bulged slightly.

At present，the conventional bonded particle model is difficult to represent the irregular structural feature of mineral grains in rock. A numerical model of thick-walled hollow cylinder of rock to reflect the feature of mineral grain in rock was established using the flat-joint contact model based upon the particle flow theory and PFC code. The failure mechanism and law of thick-walled hollow cylinder of rock with the different inner and external pressures were investigated from the meso mechanical viewpoint. When inner pressure was equal to zero，the microcracks were mainly tensile type in the failure process and the spalling fragmentation particles formed a V-shaped damage area symmetrical to the cylinder axis. When the inner pressure was not equal to zero，the limiting external pressure increased and the shear microcracks gradually dominated in the failure process with the increase of the inner pressures. Meanwhile，the symmetrical V-shaped damage area in the specimen receded and the failure expanded towards all the directions from the inner rock face. With or without the inner pressure， the variation of the failure parameters such as the external pressure and the external volume strain can be divided into three stages.

The sharp increase in size of underground structures brings great challenge to the anti-floating design. An ordinary passive scheme usually means a huge cost financially and timewise. A new active anti-floating method together with a case of application is presented. The method is to reduce the water pressure acting on the underground structures by draining the water out with a drainage corridor around the underground structure. The critical problem of the method is how to design the drainage system with the good long-term performance and how to control the environmental impact caused by the drainage. The characteristics of the drainage corridor，the factors involved deeply in design，the analysis method and the case monitoring data were discussed in detail. The proposed method has an overwhelming advantage in finance and time over the ordinary anti-floating method.

The traditional methods of shield tunnel construction bring about a large amount of problems such as structure demolition and severe traffic congestion in the process of construction. The construction technique of ground pass shield tunneling(GPST) method applied in the Nanjing airport line was investigated. Soil pressure，pore water pressure，horizontal displacement and vertical settlement were monitored in the construction site. The monitored results were analyzed for three different load cases such as the shallow overburden area，the super shallow overburden area and the negative overburden area. The reasonable and effective grouting parameters were presented. The results show that there is a relationship between the depth of the overburden soil and the soil pressure of the area affected by the shield tunneling. The right area of the negative overburden soil is mildly affected by the synchronous grouting，while the bottom segments are considerably influenced. The pore water pressure under 0.5D overburden condition has a significant effect when the notch to the first three rings，but the pore water pressure under －0.3D overburden is not obviously affected. The horizontal displacements in soil of the three cases are differently distributed. The less the depth is，the more the displacement is. In the negative and super shallow overburden soil area，the settlement of two sides are not evenly distributed and this may be attributed to the unbalanced stress of the two sides when the tunnel is constructed in the curved segment.

The deformation of tunnel is an important parameter indicating the stability of the tunnel. The roof settlement data of 836 tunnels and 806 sets of horizontal convergence data reported from 103 tunnels were collected for statistical analysis. The ground deformation surround the tunnel，the duration of the deformation and their relations with the surrounding rock classification and excavation area were systematically studied. The ground deformation surrounding tunnel was mainly concentrated in the low value zone. With the deterioration of the surrounding rock，the tunnel deformation increases and more deformation data can be observed from the high value zone. With the increase of the tunnel excavation area，the tunnel deformation value increases distinctly. It was noted that there was no obvious relationship between the tunnel deformation and the overburden depth. The duration of the tunnel deformation was mainly concentrated in the low value zone，which increases with the deterioration of the surrounding ground. The magnitudes of tunnel deformation and the lasting time of deformation for different ground types were proposed in the study.

The particle breakage of granular geomaterials under loading alters the particle-size distribution and further affects their mechanical properties. In order to reveal the effects of stress level on particle breakage，a series of confined compression tests on carbonate sand and quartz sand were conducted to investigate the compressive deformation，the stress-strain relation，the variation of particle-size distribution and the behavior of particle breakage at high compressive stress. A mathematical model was established to describe the relationship between the void ratio，the volumetric strain，the relative breakage and the stress level. Once the fractal distribution of granular geomaterials was caused by the growth of particle breakage with the increases of stress level，the ratio of volumetric strain to relative breakage remained constant. The constant ratio implies that the relative breakage may be estimated from the volumetric strain，and the value of constant ratio of quartz sand is larger than that of carbonate sand. The relationship between the increment of the pore ratio，the volumetric strain，the relative breakage and the stress level can be described respectively with a mathematical model of unified functional pattern if the particle-size distribution becomes fractal. The model can be used to predict the relative particle breakage of geomaterials in the fractal distribution stage based on the model parameters obtained from experiments.

Due to the reconsolidation after pile installation，mechanical properties of soil around old piles are extremely different from soil around new piles. Considering pile-jacking influence and initial anisotropy properties of the natural clay and adopting an analytical solution to elastoplastic cavity expansion due to the pile jacking-in，the mechanical characteristics of soil around the new and old piles are subsequently analyzed in detail. On this basis，load transfer models are proposed for new and old piles respectively according to the different mechanical properties in this paper. The theoretical solution is verified by the field test，and the results show that the presented methods predicted accurately the load-settlement relationship of the new and old piles.

In order to provide a reliable basis for the repair work of ruin，the basic characteristics of the artificial ruin soil which was mixed with the glutinous rice syrup were studied. The electron microscopy，infiltration，confining compression，static triaxial and dynamic triaxial tests were carried out. The different weight ratios of soil and glutinous rice syrup with the same glutinous rice slurry concentration and the different glutinous rice slurry concentrations with the same weight ratio of soil and glutinous rice syrup were considered. The microstructure characteristics，permeability，compressibility，deformation and structural parameters，the static and dynamic strengths of the artificial ruins soil were studied. In the artificial ruins soil，the pore arrangements are directional with the more macro pores. The permeability coefficient is decreased with the increasing of the content of glutinous rice syrup. Under the conditions of same dry density and same weight ratio of soil to glutinous rice syrup，the compression index of artificial ruins soil with the glutinous rice with density of 1.04 g/cm3 is the minimum and the compression modulus is the maximum. Under the same pressure，the structural parameter is the highest. With the increasing of the density or quality of glutinous rice paste，there is a peak value of the cohesion c，but the friction angle is continuously decreasing. There are also peak values for other parameters. Glutinous rice paste increase the dynamic strength and damping ratio，but the dynamic modulus changes a little. So the optimal ratio of the density of glutinous rice paste is 1.04 g/cm3，and the optimal mass ratio is 90∶10.

In order to investigate the stick-slip phenomenon and surface sintering of saturated granular materials，spherical soda lime glass beads were used to perform consolidated drained triaxial compression，single particle compression，oedometer and thermal melting tests. The triaxial compression experiment results showed that the stick-slip events of saturated and dense glass beads always appeared under higher confining stress. As increasing the confining stress，the mean amplitude drop of the deviatoric stress shows an exponential growth. At the slip phase，the abrupt drop of the deviatoric stress corresponds to the jump of volumetric strain. At the stick phase，the deviatoric stress increases gradually，showing strain strengthening characteristic. The sample volume contracts first and then dilates until the next slip phase. The consistency of the deviatoric stress and cell pressure is better than the pore water pressure because the cell pressure was more accurately measured. The single compression test，the oedometer test and the thermal melting test results show that in the ambient temperature condition，the sintering form of particles is totally different from the thermal melting in the high temperature condition. In the ambient temperature condition，due to the action of contacting and compressing，the surface of particles gradually dissolve and then re-precipitate on surrounding surface of glass beads，but with lower sintering strength and small morphologic change of glass beads.

A series of isotropic consolidation and shear tests under different intermediate principal stress ratio b and constant water content were performed on unsaturated intact loess with various initial suctions using the true triaxial apparatus. The yield curves in the p-s plane and the shear yield curves in the p-q plane of the unsaturated intact loess were studied. A unified expression of suction increase and loading collapse was established in p-s plane. The yielding characteristics of the unsaturated intact loess were discussed under different ratios of b. The yield suction is a constant related to the density and structure of soil. The curve of suction increase and loading collapse was universally described as a parabola. The shear yield curves are arcs in the p-q plane and are part of the yielding cone surfaces in the three-dimensional net principle stress spaces. The yielding surfaces at k0 state in the net principle stress spaces intersect with the circular conical surfaces with the increase of the ratio b，and the unsaturated loess under the condition of k0 yielded with the decrease of the matrix suction and the increase of the intermediate principle stress ratio b.