High temperature in coal mine at great depth is one of the most important factors that associate with mining disaster. It effects not only on the property of rock，but also on the safety of production in coal mine. Aiming at the present problems in the cooling technology under mining，the high temperature exchange machinery system(HEMS) technology of heat-harm control in deep mine is proposed，which put the mine discharge as the cold energy extracted source，and exchange the heat energy between the high temperature air in working face and the extracted cold energy to reduce the environmental temperature and humidity of working face. Appling HEMS technology，the first Deep Underground Science and Engineering Laboratory(DUSEL) mainly on heat-harm control is established in Jiahe coal mine. The system running results indicate that the temperature of the working face drops down to 28 ℃–29 ℃，which is 4 ℃–6 ℃ lower than the original，temperature and the relative humidity is 5%–10% lower than before. It greatly improves the working environment of the working face. The heat-harm control is efficient.

Fracture spacing is an important fracturing phenomenon in crustal rock formation and geotechnical engineering structures，but its formation mechanism is not clear. Fracture spacing in stratum，earth shrinkage and fracture spacing(zonal disintegration) in rock mass around deep tunnel all belong to fracture spacing. And fracture spacing in concrete structure，shrinkage crack on ceramics driven by cooling and drying and so on are typical models of fracture spacing. Based on the background，the results of numerical tests on mechanism and evolution laws of fracture spacing are put forward with RFPA. Three patterns of fracture spacing are：(1) parallel fracture spacing(parallel crack)，(2) net fracture spacing(crack)，(3) ring fracture spacing(zonal disintegration).

For the problems of safe and high-efficient exploitation in low permeability and methane-rich seam group，Huainan area was chosen as primary experiment base. And based on different coal seams and gas geological conditions，by means of rock mechanics，strata moving theory and “O-ring theory”，a series of engineering technologies on pressure relief gas drainage by mining the roof of the coal seams were built；and the technological system of gas drainage of pressure relief mining and integrated coal mining and gas extraction was established. The rules of rock strata moving，pressure-relieved gas moving，abundant zone of pressure-relieved gas，pressure-relieved zone and pressure-enhanced zone of mining seam were studied. The theory and technology of pressure relief gas in first-mined seam，gas in upward pressure relief seam，gas in downward pressure relief seam and pressure relief gas of surface borehole were studied. The theory and technology of pressure relief gas drainage were developed；and the problem of integrated coal mining and gas extraction was resolved.

Three methods for analyzing hydraulic fracturing of earth-rockfill dam core are described and compared，i.e. total stress method，synthesis method and conventional effective stress method. The merits and limitations of those methods are discussed. The analyses of hydraulic fracturing for Pubugou earth dam and Lianghekou earth dam are carried out using these methods；and the differences in these methods are investigated. The rationality of synthesis method is demonstrated. Some rational criteria of hydraulic fracturing for the total stress method and the synthesis method are suggested；and the shortage and improvement of the conventional effective stress method are pointed out. A new factor of safety for hydraulic fracturing is defined；and it can be conveniently used to assess the safety of dam core hydraulic fracturing. The newly defined factors of safety from different methods are used to check the capability of Pubugou earth dam to prevent hydraulic fracturing. The safety of against hydraulic fracturing for the two dams is confirmed.

In consideration of the research requirements from rock mechanics at depth，the stress states of rock in deep-level projects is analyzed；and then the research topic of rock under coupled static and dynamic loads is brought forward. After exploration on multi-load drilling machine，INSTRON system and SHPB device，a new testing system is constructed，where rock specimen deforms and fails at medium to high strain rate. With the system，rock can be loaded with 0–200 MPa axial static pressure，0–200 MPa confining pressure and 0–500 MPa impact loading respectively or simultaneously. Tests for rock strength，fragmentation behavior and energy absorption with different coupling loads show that，with the same impact loading，rock strength is greater than its individual static or dynamic strength if the axial pressure is less than 70% of its static compression strength. With the same axial pressure，rock strength under coupling loads increases with the increase of impact loading owing to the strain rate effect. Under coupled static and dynamic loads，rock breaks with tensile failure mode. As for the particle-size distribution of fragments，the percentage of small particles increases with higher axial pressure or impact loading. The energy absorption ratio varies with coupling loads. With proper combination of static and dynamic loads，the maximum energy absorption ratio can be obtained.

An essential distinction existed between unloading confining pressure and loading rock. Many factors affect on damage mechanism of unloading confining pressure rock. Taking slate in Jinping area as object of study，mechanical property and mesostructure parameter are achieved. The microcrack distribution on engineering rock is reappearance by means of the Monte-Carlo stochastic simulation. Then，the fractal dimension of unloading confining pressure rock under different confining pressures and different stages are obtained. It is a theory and reference for analyzing the microscopic changes of inner medium by means of conventional mechanics method. In conclusion：the fractal dimension of unloading confining pressure rock is magnification with confining pressure. Under the same confining pressure，the fractal dimension of post-peak is larger.

The pressure-bearing plate test is a kind of field test method which is extensively used to determine deformation parameters of rock mass. According to the field deformation test information of large-scale rigid pressure-bearing plate of Dagangshan dam zone，the loading and unloading deformation relation curves of test rock mass are described in detail. The deformation parameters such as elastic modulus，deformation modulus and equivalent deformation modulus of test rock mass are calculated by the deduced compressive deformation formula of deep rock mass. The empirical regression equations and high significance fitting curves of sound wave velocity and deformation modulus for test rock mass are got by regression analysis method. The analytical results of field pressure-bearing plate test indicate that the deformation parameters of diabase dike at dam zone are smaller，the compressive deformation of rock mass mainly concentrates in soft diabase dike interlayer and the deformation parameters of rock mass at right dam zone are smaller than that of left dam zone. These test analysis results provide important basis for revealing changing laws of mechanical parameters of dam zone rock mass.

Mainly aiming at the special geological engineering condition of Huashiban high rock bedding slope in Liangjiaren Hydropower Station，investigation on the sliding reason of the slope because of the rainfall condition after the earthquake in 1996 is carried out. The side and bottom sliding surfaces and the slope offside tensile rupture zone can be determined，there are two basic problems should be confirmed：(1) run-through ratio of the slope side and offside；and (2) the determination of rock mass mechanical parameters of the bottom sliding surface. The method to confirm these two basic problems through the back analysis of the sliding process of the slope which has been sliding in the history because of the earthquake and the rainfall，and then to compare the back analysis result from local reconnaissance with the rock experimentation results by the Guiyang Investigation and Design Institute，China Hydropower Engineering Consulting Group Co.，and the empirical values of the similar rock slope engineering in China，finally，the reasonable computing parameters are obtained. After above- mentioned work，the slope stability of the Huashiban rock high slope is analyzed，it is shown that Huashiban rock high slope will fail in abnormal state. So it is necessary to reinforce the slope. The computing results of the reinforcement position show that the reinforcement of the bottom slope can not only improve the local slope stability，but also improve the whole slope stability. Then，three reinforcement schemes based on the above work are designed；and the effects of these three reinforcement schemes on slope stability are analyzed. Finally，an optimum reinforcement scheme，which is economical and reasonable，is presented.

To the marked rheological and deteriorated characters appearing in process of the wall rock excavation and operation of the Jinping Hydropower Station long，large and deep-buried tunnel with depth of 2 525 m，length of 19 km，width of 13 m，the experimental investigation on the shear rheological character of marble with hard structural surface is done by using the CSS–283 two-way universal testing machine；the relationship among stress level time and viscoelastic deformation disciplines of rock is analyzed. Based on the profoundly research to the test data and the constitutive equations of stationary rheological model，the non-stationary parameters are achieved，and the non-stationary rheological model and a one-dimensional creep equation is established. By the comparison with the theoritical results of the stationary and non-stationary rheological models and the test results，the results indicate that the non-stationary viscoelastic Maxwell rheological model，considering time-dependent behaviors of the parameters，is the more exactly reflect the rock viscoelastic deforming performance than the stationary viscoelastic rheological models. The research result is a preliminary exploration on the research of the rock non-stationary rheological model；and it offers reference value to the research of the long，large and deep- buried tunnel of the Jinping Hydropower Station.

With the special characteristics of fast tunneling，the double-shield TBM is suitable for long tunnel construction. But for pressure tunnel in hydropower engineering，the loading capacity of segment lining for tunnel under high inner water pressure is one of the keys to determine whether the segment lining is feasible and the double-shield TBM can be used for the tunnelling construction. Combined with the long pressure tunnel of the Qingsong Hydropower Project，the characteristics of deformation and stress distribution of segment lining are evaluated by calculation with 3D FEM；the important influential factors are analyzed；the stress and strain distributions in different conditions are obtained；and the knowledge for segment lining characters is deepened. It is found that the segment lining has the character of flexibility，and under the present technology of joint water-seal，as far as the Qingsong Hydropower Project is concerned，the segment lining can sustain the high inner water pressure. The conclusion is helpful for application of segment lining and double-shield TBM in hydropower engineering in China.

According to the mechanical analysis of principle of steel fiber reinforced shotcrete structure，the applicability of steel fiber reinforced shotcrete in the tunnel of single-layer permanent lining is researched. The mechanics function mechanism of steel fiber reinforced concrete is analyzed firstly，and then the reasonable proportion，tension，resistance of compression，flexural strength，first-crack strength and index of flexural toughness of steel fiber reinforced shotcrete are completed by laboratory test. Moreover，combined with the typical spraying test in tunnel engineering，the measured data of stress in wall rock，spray stress of steel fiber concrete and level convergence in tunnel are analyzed. The spotting spraying experiment in tunnel shows that the tensile strength and toughness of the steel fiber reinforced shotcrete are higher than those of general one，the stress distribution is more homogeneous，the yield capacity is better，and the rebound of the steel fiber reinforced shotcrete is reduced. The results show that steel fiber reinforced shotcrete is perfect timbering material for single-layer permanent tunnel lining and it has wider application.

According to the basic laws of water movement and heat migration about rock mass under the freezing- thawing cycle condition，based on the theory of continuum mechanics，thermodynamics and segregation potential，the coupled equations of seepage field and temperature field are established. This model can not only consider the influence of thermal conduction，latent heat and seepage velocity on the distribution of temperature，but also analyze the effect of water flow induced by segregation potential on the seepage velocity and seepage pressure. To verify the reliability and rationality of the equations，the comparison is done by using the same conditions between the model test which was done by M. Smith and the finite element analysis using this coupled mathematical model. Then the model is applied to a cold regional tunnel，and the distribution of temperature and active ring of permafrost are obtained. The results can give some references for design and construction of tunnel in cold regions.

Bifurcated tunnel is one of the new type tunnels，the excavation way and support style are key factors to the rock stability. A case study of Miaoya bifurcated tunnel is given；based on the character of large-span shallow part of bifurcated structure，the contents，technique，and method of monitoring in large-span shallow section are presented. Based on the measured data，such as the ground settlement，rock deformation，bolt axial force，concrete ling stress and so on，the deformation and stress properties of surrounding rocks and supporting system are analyzed；in addition to the blasting dynamic characteristics of ground vibration for the serious blasting damage of shallow ground vibration，the in-time information is applied to guide tunnel construction and optimize the supporting system，and monitoring results are discussed in detail. The study provides indispensable evidence for the design and construction of the bifurcated tunnel.

he prediction theory and forecast method of tunnel water gushing in karst areas have long been a difficult hydrogeological problem. Based on analyzing karst tunnel water gushing examples in recent years in China，the mechanism of geologic structure for water gushing has been explained through analyzing different karst hydrogeological storage structures；and the existing problems of tunnel geological forecast instruments have been pointed out. In order to find accurate calculation method of water inflow，detailed analysis has been done for the advantages and disadvantages of different calculation methods，as well as its applicable condition. According to different hydrogeological conditions of aquifers，a reasonable and accurate calculation method is put forward. This division system has been further proven in its application of field test.

Because of the complicated geological conditions，fragmentation of ore and rock mass，developed underground water，Luzhong iron mine is one of difficult excavation mine in China. According to the conditions of the very broken orebody in Luzhong mines，so they are difficult to be mined safely；the dynamic monitoring of the law of stope ground-pressure was carried out. The change of stope ground-pressure was measured by using the borehole strain sensor；and the electronic digitally-displayed convergence indicator was used to measure deformations of surrounding rock so as to obtain a general law of the ground pressure. This technique provides a scientific basis for selecting rational mining method and ground-pressure control measures.

he probability distribution model of discontinuities is established through the three-dimensional network modeling based on real joint distribution accessed geological survey in-situ. The fracture network coupled seepage model based on interface stress element can be founded by the use of hydraulic parameters and geometry parameters to characterize space structure infiltration layout in rock mass，which can access rock network fractured seepage path，and also it can calculate the water heat distribution，then it can search out all limited block in the exposed surface sections and determine its space geometry and geometric parameters，to achieve to search automatically the instability key block. All of these are of great significance to evaluate and predict the stability of the key block.

When crossing the Qingquanjie fault fragmentation zone in Guangzhou metro tunnel，the application of freezing method to construction of the connected aisle for metro project is introduced．During the construction，the stress and deformation of supporting structure，tunnel deformation constringency，ground displacement，stress of surrounding rock，stress of steel grille，the deformation of the ground surface in the course of freeze and thaw are tested. On the base of testing result，the stress and deformation of structure and environment soil are put forward studied. The laws of the survey results are examined. Finally，based on these studies，some suggestions are for guiding the construction about the freezing method and construction. The results can be used for reference of similar projects.

In-situ leaching(ISL) is a typical flow process coupled with chemical reaction and solute transport. The permeability distribution of porous ore deposits will change dramatically during leaching process，and it may lead to preferential flow or “dead leaching zone” that decreases the overall recovery rate of minerals. Existing leaching apparatuses mainly focus on the chemical process under atmospheric pressure，and can not perfectly model the in- situ condition with high confining pressure and fluid pressure. Permeability of uranium orebody may change by several orders of magnitude during leaching process. These apparatuses are not suitable for high precise and large-scale permeability monitoring. For these reasons，a new rock-fluid reaction-flow coupling testing apparatus is developed. The flow rate，pressure，different pressure，fluid component can be gained simultaneously with this apparatus. Permeability，solution transport coefficient，and chemical reaction rate can be obtained by analytical methods. The apparatus is used for natural reagent leaching experiment with natural ore bearing aquifer groundwater. Experiment results show that uranium recovery rate is about 60% when the liquid solid ratio reaches 4，and permeability changes by 3 orders of magnitude during natural reagent leaching process. The experiment proves that the rock-fluid reaction-flow coupling testing apparatus works well and efficiently，and in-situ uranium leaching by natural ore bearing aquifer groundwater under oxygen oxidizing condition is applicable and effective. The results also show that field leaching experiment may face non-uniformity flow which will decrease recovery rate.