In order to control and forecast geological disasters such as deep rock burst of high stresses，pressure bump and landslides，a new constant resistance and large deformation(CRLD)bolt/cable with negative Poisson?s ratio(NPR) was developed. The concept and mechanical behavior of NPR support were firstly put forward in view of the excellent performance of NPR materials or structures such as anti-impact，anti-shear and energy absorb. Based on the rheological mechanical and analytical model of NPR structure，the unified ideal elastic-plastic constitutive relation for NPR bolts/cables and NPR rock was verified theoretically. The proportional NPR support system was formed. Through the static tensile test，anti-impact and anti-explosion underground tests and landslide monitoring test，the correctness of the theoretical model of constitutive relationship was verified and the control and prediction of large deformation in open pit and underground mining were achieved effectively.

The field investigation，laboratory experiment and numerical computation were carried out to systematically analyze the B-type breccia from a hydropower station. The laboratory test results indicated that the B-type breccia exhibits typical elasto-brittle-plastic feature under the confining pressures of 0–15 MPa. The specimen deformation tended to be uniform under relatively high confining pressure. Therefore，the elastic modulus had little relationship with the confining pressure. Due to the different calcite contents in the specimens，the peak strengths of the specimens differed markedly. Peak strength increased with the increasement of calcite contents. Compared with natural specimens，the internal friction angle of saturated specimens increased while cohesion decreases，which illustrated that water strengthened the bonding effect and weakened the internal friction coefficient；Three-dimensional numerical model including breccia mass was established. Mechanical response of B-type breccia under excavation was obtained through numerical computation. The numerical computation results fit well with monitoring data. It indicated that the surrounding rock was steady after systematic reinforced support have been set.

In order to understand the effect of dry-wet cycles with acidic wetting fluid on the strength deterioration of shaly sandstone，the shaly sandstone at the slope of the Three Gorges Area in Chongqing was selected for study. The shaly sandstone specimens were exposed to n dry-wet cycles with an acidic solution(pH = 3)(n is the number of cycles). The specimens were treated through indoor uniaxial and triaxial compression tests and were scanned with an election microscope. The discrete element software PFC2D was used to simulate the particle contact and crack distribution of the specimens(n varies) at the peak strength in the triaxial compression test. It was found that the uniaxial compressive strength(?)，elastic modulus(E)，cohesion(c)，internal friction angle(?) and triaxial compressive strength(?′) of the specimen decreased with the increase of n. When n=1，the strength parameters show the greatest degree of deterioration. The dry-wet cycles have a greater impact on the deterioration of c than on ?. As n increased，the shaly sandstone was changed from a well-organized dense structure to porous floccules and then to a turbulent flow according to the microscopic observation. In addition，when the strength reached its peak value in the triaxial compression test，the increase of n had a significant effect on the contact network of particles，the microcrack development and the failure mode of the shaly sandstone specimens.

1D and 2D particle flow numerical models were generated respectively based on the particle flow theory in order to study the stress wave propagation induced by the low frequency dynamic loading. Firstly，P wave propagation in the 1D particle string models were studied systematically from several aspects including the excitation types of source，bond model types，numerical dispersion effects and boundary conditions，which provided the reference data for simulating the propagation of stress wave in 2D particle flow model. The simulation results of large-scale 1D particle string model(6 400 m) indicate that it is better to choose the Ricker wavelet than the sine wave as the seismic source of wave field，because the Ricker wavelet has no high frequency corners；For the particle string model with contact bond，the amplitude of P wave decreased with the distance from source，but the velocity was almost constant，with the relative error of 0.12% compared with the theoretical result. For the particle string model with parallel bond，the waveform of P wave distorted intensely. Numerical results of the effects of dispersion increased with the dominant frequency of Ricker wavelet as well as distance from source. However，the wave frequency mainly reduced the amplitude，but the distance from source reduced both the amplitude and velocity. What?s more，for frequency f≤60.23 Hz，the relationship between the angular frequency   and wave number   is almost linear，and the dispersion in models is negligible. For the rigid boundary，the amplitude of reflected wave is identical to the incident wave and opposite in sign，and the displacement at the boundary is zero；For the free boundary，the amplitude of reflected wave is identical to the incident wave，and the amplitude at the boundary is twice that of  the incident wave；For absorbing boundary，the amplitude of reflected wave was reduced about 96.8% relative to the incident wave，indicating that it the impact of reflected wave was reduced effectively. According to the above conclusions，the contact bond model was adopted and the absorbing boundary was applied in the large-scale 2D hexagonally packed particle flow model(3 000 m 3 000 m). The characteristics of P and S-wave front，waveform and wave velocity variations were analysed in details. When a concentrated force is applied to the source，there exists P wave and S wave excited by the point source in the model. The presence of S wave proves that geometrical arrangement of particles in the model has a tremendous influence on the propagation of stress wave. When the frequency of the source is constant，the amplitude and velocity of P wave and S wave decrease with the increase of the distance from source due to dispersion，and the dispersive effects of S wave are greater. When a concentrated force is applied to the source，the amplitude of P wave displacement field reaches a maximum along and zero perpendicular to the axis of the applied force，while the amplitude of S wave displacement field reaches zero along and maximum perpendicular to the axis of the applied force.

The tests on raw coal and moulded coal specimens under impact loads were performed with the drop hammer impact test device developed in-house. The effects of the number of impact loading，the magnitude of the energy of a single impact，the accumulative effects of impact energy and the energy sequence of impact on the internal micro-structure of coal were studied according to the distribution of T2 spectrum of specimens measured with the nuclear magnetic resonance(NMR) analyzer. The results show that there are some differences between T2 spectrum distributions of raw coal specimen and moulded coal specimen. The quantity and size of internal micro-structure of specimens，especially of raw coal specimens，were increased due to the dynamic loads. The total quantity of internal micro-structure of coal increased nonlinearly with the increase of impact times with a trend of rapid increasing，gentle development and sharp increasing，and increased nonlinearly with the increasing of energy of single impact. Due to the coupling effects of the threshold and absorption rate of impact energy，the accumulative effect of impact loads on internal micro-structure of coal is also nonlinear and has a decreasing trend after the first increase. The accumulative effects of impact loads cannot be simplified as the increasing of the impact energy. The total quantity of internal micro-structure of coal is more sensitive under decreasing cyclic loading than increasing process，so the reservoir can be efficiently stimulated by adjusting the construction sequence in the engineering field.

In order to explore abnormality of infrared temperature field(ITF) in the process of rock cracking and destabilization，the concept of infrared temperature variation field(ITVF) was put forward in the paper，and the transient characteristics of ITF during rock failure was analyzed and discussed based on the experiment on saturated siltstone samples under thermal imaging observation in loading process. A certain abnormal phenomenon of ITVF during rock instability was found. The abnormal jump of ITVF characteristic parameters，including Range(R)，Kurtosis(K)，Mutation Ratio(MR)，etc，exists in the failure process of saturated siltstone. The occurrence probability of anomalies was up to 88.8%，mainly in the plastic and post-peaking phase，especially tending to appear at the moment of marked pressure dropping. When the deformation entered into the plastic and post-peaking phase，ITF jumped due to the intensified development of specimen surface fracture and the infrared temperature variation rate moved to the direction of the maximum or minimum，which resulted in the abnormal jump of R and the sudden increase in the number of ITVF abnormal value，thus caused K and MR a sudden jump. The ITF anomalies generally exist in the process of ductile fracturing of rock.

Due to the restriction of topography and the interaction between related engineering，the probability of occurrence of high density underground caverns is increasing. The relationship between each cavern and the overall stability of the caverns，the dominant failure mode and how to design the strength of supporting measures of each cavern reasonably to realize the equal strength theory are becoming increasingly urgent. The feasibility and reasonability of the application of the main current criterion to gain safety factor in caverns were analyzed based on the theory of finite element strength reduction and some large high-density underground caverns in Chongqing. Based on the least square method，the relationship between the safety factor and the final lining thickness of each cavern is expressed through the quadratic polynomial and the thickness of each final thickness is optimized by the genetic algorithm. The local failure of the secondary parts such as the surrounding rock between caverns influences little on the stability of each cavern or caverns. The dominant failure modes of parallel caverns can be classified into three categories determined by many factors such as the distance between them and the embedded depth. When the embedded depth is shallow and the distance is large，the plastic region near the vault of each cavern grows upward to the surface in the direction opposite to the center of the caverns and finally results in failure. When the embedded depth is deep and the distance is small，the plastic region near the vault of each cavern grows upward in the direction to the center of the caverns and finally results in failure. When the embedded depth and the distance are in moderate sizes，the above two failures contribute to the failure together. For the various dominant failure modes of caverns，the curves depicting the relationship between the displacement of key points and the strength reduction factor may be less obvious and the distribution and development process of plastic zone should be resorted to simultaneously to obtain the safety factor of cavern. The expression of implicit relationship of quadratic polynomial based on the least square method and the optimization of the thickness of final lining by the genetic algorithm achieved a certain fitting precision and ideal optimization results.

The analysis of the movements of various meso-compositions of granite specimen is of great significance in exploring the deformation/failure process of rock material and can be performed using the video image processing techniques. In the current study，the video images were photographed during the laboratory axial compression test. The frame images were extracted from the original video recordings and transformed into the grayscale and binary ones. The actual distributions of the quartz，feldspar，and biotite existed on the specimen were pin-pointed according to the image features of the corresponding compositions. The Fourier transform based shape indices were then used to describe the geometry features and to examine the changes of the indices with time. The particle image velocimetry technique was thereafter used to compute the displacements of various meso-compositions at different times. The relations between the deformation/failure of the specimen and the movement directions/sequences of the meso-compositions were also explored. It shows that Fourier indices may effectively quantify the shape characteristics and their changes of meso-materials on the granite specimen. During the axial compression，the failure of the meso-compositions in the granite specimen were in sequence of biotite，feldspar，and quartz. The components perpendicular to the axial load were the principal parts of the displacements in these minerals.

To solve the low permeability of sandstone-type uranium deposits to satisfy the basic needs of in-situ leaching mining，this paper presents the preliminary and optimized model tests of the blasting-enhanced permeability method of low-permeability sandstone-type uranium deposits(BEPUD). The permeability of the models was also evaluated based on the BEPUD. Experimental results indicate that the permeability of the models after blasting increased by two to three orders of magnitude. The enhanced permeability range was approximately 70 times the radius of the blasting cartridge，and the reasonable decoupling coefficient ranged from 1.5 to 3.0. The mechanisms of blasting-enhanced permeability were analyzed based on the dynamic fracturing of rock，the millisecond blasting，the decoupled-charge blasting，the space compensation，and the drive effect of exploding gas. This research lays the foundation for perfecting BEPUD and develops a pilot site test and scale application of this approach.

The scaled driving test was carried out to study the disturbance of EPB shield tunneling to the sandy cobble stratum and sandy stratum using ? 800 mm EPB shield tunneling system. The deformation and failure mode of the excavation face were analyzed using DEM. The profile of three-dimensional trough of surface settlement in sandy stratum has the shape of “round funnel” with a gradual contraction from top to bottom while that in sandy cobble stratum looks like a “Valley”. The width coefficient of surface cross-section trough of sandy cobble stratum is smaller than that of sandy stratum. The subsurface trough width parameter of both stratum increased linearly with the depth ratio. When the depth ratios are the same，the subsurface trough width parameter of sandy stratum is larger than that of sandy cobble stratum. The time-effect curve of ground settlement of sandy stratum shows gradual and continuous characteristics while that of the sandy cobble stratum shows settlement jumps. The deformation and failure modes of the excavation face in both stratum show a chimney shape，but the disturbance scope in sandy cobble stratum due to excavation is smaller than that in sandy stratum.

With the world's increasing demand for mineral resources and energy，the mining activities of human being have entered deep underground. In order to reveal the nonlinear deformation properties and strength failure mechanism of ultra deep cavern under high ground stress，a 3D ultra high pressure loading model test system with intelligent control function was developed by using the numerical control and photoelectric conversion technology. The model test system is composed of a counter-force frame，an ultra high pressure loading system，an intelligent hydraulic control system，an automatic collection system of model displacement and a high definition multi probe peep system. The rated output of the model system is 63 MPa，the maximum load is 45 000 kN and the loading accuracy is 0.05 MPa. The true 3D non-uniform gradient loading at super high pressure is realized with the numerical control technology. The automatic monitoring of the model displacement is realized with the photoelectric conversion technology and the precision of displacement measurement is 0.001 mm. The failure state of the model cavern is observed through the multi probe system of high definition. 3D geomechanical model test of failure of ultra deep oil karst cave in Tahe Oilfield in Xinjiang was carried out by utilizing the model test system. The failure mode，the nonlinear deformation characteristics and the stress variation of the karst cave in the process of formation were effectively revealed. The results of the model test has verified the reliability of the model test system.

In order to improve the accuracy of stability analysis of slopes under the condition of rain softening，the modes and criterion of failure of soil slopes of road subgrade were analyzed. For the different rain softened depths，three types of failure modes occurred including soil slice type of unit width，composite type，and integral type. The ratio ? of the length of slip body to the softened depth was taken as the characterization parameter of deep and shallow slope failure category，and the thresholds λcr and λf of three modes were presented. According to the limit equilibrium condition of rigid body，a unified formula of stability safety factor based on the composite type failure mode was established. The results show that threshold ?cr of unit width soil slice type and composite type and threshold ?f of composite type and integral type are not significantly affected by the strength and geometric parameters of the slope，and are between 15.2–20.0 and 3.0–6.3 respectively. If ? was less than ?cr，applying the parallel slope-plane mode produced the conservative results due to the ignoring of the mechanical effect of the upper and lower edge. If ? was more than ?f，applying the integral curve represented by circular slip surface yielded larger safety factor. But if ? was less than ?f，applying the logarithmic spiral or circular arc sliding mode yielded no significant difference.

The existence of voids behind highway tunnels in water-rich strata deteriorates the stress state of the lining structure，make it vulnerable to cracking and affects its integrity during service. A device for external loading test was therefore developed with a controllable air pressure between the primary and secondary linings. The voids can be simulated by regulating the pressure difference，equivalent water pressure in the voids. Using this device together with a tunnel-ground simulation facility，a model test with a geometric similarity ratio of 1:30 was conducted. The force distribution and cracking features on the secondary lining with respect to different external water pressures and void distribution were analyzed. The axial force and bending moment distribution on the secondary lining were found no longer be symmetrical due to the voids. The voids at different location impacted differently to the mechanical behavior of lining，especially at locations near the voids. In the area close to the voids，the axial force and bending moment increased at a rate significantly higher than in other parts of lining. As the external water pressure increased，a nearly linear increasing trend of axial force and bending moment was observed irrespective of the void locations. The eccentricity decreased as the water pressure rose，and it tended to remain constant once the water pressure reached 150 kPa. Given the same pressure level，the axial force and the bending moment in tunnels with widening band were significantly greater than that in three-lane tunnels，though the distribution was similar. In the cases where the vertical stress field dominated，the voids behind the left wall had the most significant effect on the bearing capacity of lining，followed by voids behind the crown and invert. Both the number and severity of cracks on the lining with voids presented nearby exceeded the other parts noticeably.

Short-millisecond blasting with high-precision detonators is an effective way to improve the efficiency of excavation of ultra-large section and high shaft and to reduce the blasting vibrations. The formation process of the blasting crater due to short-millisecond spherical blasting was analyzed. The methods of calculation of the time delay of detonating between the holes of same segmentation and between the holes of adjacent segmentation in shaft excavation by deep-hole blasting were studied. An elastic calculation model was established to analyze the crashing effect of rock and the vibration in shaft excavation by deep-hole blasting under different short delay intervals. The simulated results showed that the optimum time delay of detonating between the holes in the same segmentation was 9–11 ms according to the related parameters such as the peak effective stress，the effective stress time and the peak vibration velocity. The research results of theoretical analysis and numerical simulation have been successful applied in an ultra-large section surge shaft. The bottle neck problems referring to the excavation efficiency and vibration reduction in ultra-large section and high shaft excavation have been solved.

A simplified method for estimating the landslide lateral loads acting on the stabilizing piles，called unbalanced lateral load transfer method，has been used for decades in China. However，the method do not consider the reaction force of piles in the force components acting on a typical slice，which may result in calculation errors. This paper presents a modified formula based on the unbalanced lateral load transfer method. The horizontal reaction force of pile is added into the force components acting on a typical slice. In this way，the horizontal lateral loads acting on the stabilizing piles can be estimated through the strength reduction(the reduction method is equal to the target factor) based on the force equilibrium analysis. As a result，the estimated stability factor of safety of landslide reinforced by stabilizing piles is equal exactly to the target factor of safety.

To analyze the stability of Qinghai—Tibet Railway(QTR) which was constructed on the slopes with rich moisture and high temperature in permafrost regions，a test section of traditional slope subgrade in K1139+940 of QTR was seleted to monitor temperature and deformation. A coupled heat-moisture-deformation model was used to simulate the influence of seepage on temperature and deformation of subgrade with the finite element method. The results showed that the temperature difference between the shady and sunny slopes was marked and the annual mean temperature at the depth of 0.5 m in the sunny slope could be over 2.5 ℃ higher than that in the shady slope. At the early operation of QTR，the artificial permafrost table moved downward and the ground temperatures rised under the left shoulder，and opposite under the right shoulder. The temperature difference between the shady and sunny slopes led to the uneven settlements transversely. Seasonal water flow in active layer had more remarkable effects on the temperature and deformation of the sunny slope than those of the shady slope. Moreover，water flow accelerated the warming and subsiding process of subgrade and intensified the asymmetrical distribution of thermal regime and deformation regime in subgrade. The ice-rich layer under the embankment will thaw completely and the maximum lateral deformation difference will be 18cm in 50 years after the constuction. The settlement due to thawing and compression of ice-rich layer and high temperature permafrost will dramatically reduce the stability of the subgrade slope.The effect of seepage on the thermal and deformation regimes should not be neglected for the subgrade slope with rich moisture and high temperature in permafrost regions.

According to the interlamellar hydration model of montmorillonite proposed by Forslind，an equation is established for predicting the specific gravity of montmorillonite at the end of the hydration process. When the solvent is pure water in measuring the specific gravity，the larger the total specific surface area and thickness of interlamellar hydration layers of bentonite are，the greater the specific gravity of bentonite is. The interlayer thicknesses of calcium bentonite from Gaomiaozi with different initial water contents and saturated using ethylene glycol were determined with the X-ray diffraction and were approximately the same. By comparing the measured and predicted values of the specific gravity of sand and bentonite using pure water and kerosene respectively，it was found that the solvent influenced the specific gravity of bentonite. The measured specific gravity using pure water is larger than that using the kerosene，which verified the rationality of the proposed formula.

Electronic density gauge(EDG) is a test instrument which could determine the dry density quickly and nondestructively. However the domestic application experience is rare. The measured results of loess with good homogeneity using the sand cone method，the oven-drying method and EDG were analyzed and the reasons causing the errors in EDG were found，so that the accuracy and the applicability of EDG in determining the dry density were determined. The impedance and the ratio of the capacitance over the resistance were all influenced by the density and the volumetric moisture，which was found to be the main reason causing the measurement error of EDG. The error varied with the dry density and water content. The error was smaller when the dry density and water content of the sample were within a particular range. Outside the range，the error was larger. Keeping the soil uniformity and moisture content changing within a small range are the premise of guaranteeing the accuracy of EDG measurement. It is necessary to analyze the error distribution of the soil model used in practice，and to confirm the application scope of dry density and water content to ensure a small error.

Ground fissure is a kind of special geological hazard resulting in the vertical dislocation of strata and ground surface rupture，which may cause severe harm to engineering structures. Unlike the ordinary stratum stress caused by the soil gravity，the additional soil pressure induced by the ground fissure activity is different and often causes the underground structure to appear longitudinal tension crack and even direct shear failure. Determining the effective strata load in the zone with ground fissures is the key to the structure design of underground engineering crossing over the ground fissure belts. The metro in Xi?an crossing the ground fissures is studied in this paper. A load-structure model between the metro tunnel and surrounding soil in the active ground fissure environment was established on the basis of mechanism analysis and results of physical model test. The model was used to calculate the overlying vertical formation pressure of metro tunnel structure crossing ground fissures. A method of calculating the overlying load on the metro tunnel caused by the ground fissure activity was put forward and compared with the calculation method based on A. Marston principle and the method from the Code for metro design in China. The method was verified with the model test results.

Xining basin and the surrounding area were selected as the experimental zone. 2 herbs-Elymus dahuricus and Agropyron trachycaulum and 2 shrubs-Caragana korshinskii and Zygophyllum xanthoxylon，had been growing on the slope with the angle of 30° for 150 days. In-situ shear tests were conducted to estimate the contribution of plant roots in enhancing shear strength of soil in two scenarios，the herbs only or shrubs only planting and the mixture of herbs and shrubs planting. On this basis，Wu-Waldron-Model(WWM) was used to evaluate the effects of both the single planting and mixed planting of herbs and shrubs in reinforcing the slope soil. The values calculated with WWM and from in-situ shear tests were compared. The results of in-situ shear tests on the root-soil composite systems showed that the shear strength of the samples of root-soil composite system improved more significantly than the samples of soil without roots. The shear strength of the root-soil composite systems with monoculture herb or shrub increased from 47.61% to 98.24%，and the shear strength of root-soil composite systems with mixed herbs and shrubs increased from 104.47% to 173.93%，indicating that the effect of reinforcement of the mixed planting of herbs and shrubs are better than that of monoculture. Under two kinds of planting forms (single planting and mixed planting)，the shear strength of root-soil composite systems from WWM model and in-situ shear test are basically consistent.

A method to detect the integrity of bored piles with mud intercalated based on the temperature measurement technology with optical fiber was proposed. The measurement apparatus and process were introduced in detail. The basic principle of this method was described by the heat-transfer process between the optical fiber and bored pile. Integrity pile model tests were carried out. The linear relationships between the temperature rise and heating power were obtained. The differences of temperature rise of optical fiber in bored pile and in air were compared. The tests about piles with mud intercalated were carried out containing four different kinds of clay contents，33.3%，50%，66.7%，and 100% respectively. The relationships between the heating power and the optical fiber temperature rise were analyzed and a good linear relationship was discovered. The results indicate that the method is feasible for integrity detection of bored pile with mud intercalated.