According to the papers published in some relevant journals in the field of rock mechanics and geotechnical engineering in China，the representive papers published in recent years written by Chinese authors are analyzed. In association with China National Awards，“973 Program”，“The Major Projects of National Science Foundation”，and“TAN Tjongkie Lecture”etc.，in the last decade，the challenging，development and relevant progress in rock engineering field are summarized. The major issues，key theories，engineering survey and design，rock excavation and reinforcement，and early warning and forecast in rock engineering are presented. Some typical rock engineering cases in China are also analyzed. Based on analysis of characteristics and associated problems in Chinese rock engineering developments，ten challenging issues in rock engineering are proposed subsequently；furthermore，some suggestions are given for adressing those problems.

Using self-developed meso-shear test equipment for coal and rock containing gas，tests of raw coal containing gas under compression-shear stress were carried out to study the meso-cracks? dynamic evolution. The formation of gas migration pathways is described；and the factors influencing meso-morphological characteristics of cracks are analyzed. The results show that the evolution of cracks provides pathways for gas migration in coal continuously. Coal surface crushes and then drop as the gas pressure and compression-shear stress on coal simultaneously. The fractured zone has more initiations of cracks conversely. Both the horizontal original cracks and hard granules have effects on the meso-cracks；cracks initiate more easily when encounter the original cracks；then the newly formed cracks and the original cracks together make the composition of an H-shaped one locally. There is also always a dislocation for newly formed cracks subjected to the original cracks. The evolution directions of cracks change because of the existence of hard granules which are always bypassed，the bifurcation angles range from 10°–100° which shows obvious discreteness and meso-cracks are formed by tension and shear together. There are more pathways for gas migration as the existence of original cracks and hard granules. Both the fracture distribution rate and coal crushing extent increase as the normal stress increases and the effect of initial damages and hard granules.

Based on the gob-side entry retaining reparation engineering of first coal mining face in Zhuji mine around 900 m underground，deformation，stress and structure state of roadway surrounding rock before reparation were analyzed by field measurement and theoretical method；the conception of“critical structure between instability and stability”of gob-side entry retaining reparation was proposed；reasonable repairing time and construction process were determined；initiative-passive collaborative supporting system was concluded. Research result was applied to the gob-side entry retaining reparation engineering in Zhuji mine successfully. The results of ground pressure monitoring show that the deformation of this repaired roadway is controlled effectively；and all indices satisfy the requirements of next mining face.

The research is the first case that assessing the long-term effect of ultra high-water material backfilling method. It is based on an engineering case of the open backfilling method using ultra high-water material on working face No.6 at Taoyi coal mine. The microseismic monitoring and the stress dynamic monitoring of surrounding rock are used，in combination of the surface subsidence monitoring result，to evaluate the effect of large areal gob controlled by this certain backfilling method. According to the monitoring data，with the condition of mining height of 3 m，about mining depth 300 m，inclined length of 120 m on the working face No.6 at Taoyi coal mine，the maximum height of the overburden rock fractured zone is 48 m；the influence extent of the front abutment pressure is 35–40 m；and the maximum surface subsidence upon the working face is 98 mm. The results show that the open backfilling method with ultra high-water material controls the fractured zone of surrounding rock effectively and provides a remarkable reduction of the influence of mining activities. The backfilling method has a notable effect especially on the overhand mining working face.

The compaction tests of clay mixed with gravels with two kinds of compaction，three kinds of compaction size and eight kinds of gravel-doped amount，were performed to study its granule curve，optimum water content，maximum dry density，broken rate，fines change and so on. The results indicate：the key factors of compaction characteristics of clay mixed with gravel are the size effect，skeleton and gravel-doped amount. The grain grading of clay mixed with gravels tended to be good under the effect of compaction stress；and its optimum water content decreases with the gravel-doped amount increasing；crushing occurs mainly in the range of particle size greater than approximately 0.5 times of the maximum particle. When the proportion of gravel-doped amount less than 60%，the results of 300 compaction under 2 690 kJ/m3 is entirely appropriate as the quality control standards of oversized clay mixed with gravels. For the compactness of oversized clay mixed with gravels，particle size of less than 20 mm could be better reflect the fines changes.

In order to study the time-dependent deformation behavior of bedding anisotropy green schist of Jinping II hydropower station，this paper investigates the creep behavior of brittle bedding anisotropy rock by uniaxial compression creep experiments in laboratory. Six specimens were prepared with different inclination angles of bedding planes. Loading stress levels were graded 4 classes，and the maximum value of them were all approximately equal to the existing maximum initial geostress. All the strain-time curves of specimens did not exhibit the accelerated creep stage. The instantaneous elastic modulus and steady-state creep rate of specimens were obtained and analyzed based on the experiments data. The results show that the instantaneous elastic modulus of the specimens increases with the increment of stress level；and they were higher when the bedding planes are oblique to the compression direction；and the steady-state creep rate of the specimens increase with the increment of both stress level and the inclination angle of bedding planes；it reaches the maximum value with the inclination angle of the specimen close to the failure angle of rock.

The permeability of interlayer is a key parameter for the tightness evaluation of energy storage caverns constructed in bedded rock salt formations. Thus，the steady gas flow method of permeability tests for typical interlayers of 3 kinds of bedded rock salt areas of China，as well as the analysis of tightness evaluation，has been carried out. The research indicated that：(1) The low permeable properties of the three kinds of typical interlayers are very obvious，with the corresponding permeability range of 10－2–10－5 mD. Due to the large difference of petrophysical properties and geological conditions of interlayers in different areas，the permeability exhibits obviously different with each other，in which the anhydrite mudstone of Pingdingshan has the lowest permeability，but the variance range is the medium；the calcareous mudstone of Jintan has the middle permeability，but the variance range is the maximum；and the saline mudstone of Huai?an has the highest permeability，but the variance range is the minority. (2) The hydrostatic stress states greatly influence the permeability，exhibiting the permeability decreasing as hydrostatic stress increasing. The“compaction criticle pressure”phenomenon is obviously for permeability. When the hydrostatic stress is lower than the transition stress，permeability decreases rapidly(about 1–2 orders). However，while beyond the transition stress the permeability decreases very slow and sustains steady gradually. The fitting relationship of hydrostatic stress versus permeability can be basically expressed by power function： (K is permeability，P is hydrostatic pressure，A and B are fitting parameters). (3) The mechanism of the permeability?s development versus the hydrostatic stress informs that the compressibility of porous interlayer rock. But the compaction effect will become lower and lower even become almost useless while the hydrostatic stress has reached some threshold value；so the permeability will not decrease after then. The test results presents that the permeability of the typical interlayers in bedded salt rock in China is very low so the tightness of storage caverns is basically satisfied.

There are strong correlations between deformation modulus of rock mass and physico-mechanical parameters or rock mass quality indices. These correlations were usually used for the estimation of deformation modulus. However，most of these correlations are established between a single parameter and deformation modulus；the other related parameters obtained from the in-situ tests or engineering geology survey are underused. Based on the correlation investigation between deformation modulus and wave velocity( )，deformation modulus and Q system，wave velocity and Q system of marble rock mass in Jinping I hydropower station，taking the advantage of Copula functions that can describe the correlations of multivariate，the optimal fitting Copula function of  - -Q is selected. Then it has been applied to the estimation of deformation modulus. The result shows that Clayton Copula is the optimal fitting Copula function of Em- -Q. The guaranteed rates of estimated  by other methods can be obtained；and the estimation of can be calculated with a certain guaranteed rates；the optimal fitting estimation of   can be obtained with known   and Q system by solving the conditional probability of the optimal fitting Copula functions. The multivariable correlation of rock mass quality，wave velocity and deformation modulus is established by this paper?s method. It takes full use of the information from the in-situ tests or engineering geology survey. It provides a new approach for establishing the correlations between deformation modulus and parameters of rock masses and estimation for deformation modulus.

Aiming at specific rock mechanical problem which is about excavation-induced relaxation of rock foundation，key technologies such as criterion and calculating method of relaxation，finite element algorithm of relaxation effect are deeply studied. Based on laboratory and in-situ rock mechanical experiments，an experiential formula of the shear safety factor effect is provided when rock is anchored. A practical finite element algorithm for the evaluation of relaxation and anchor effect is established. Taking Xiaowan arch dam as background，spatial-time distribution of foundation rock mass relaxation is displayed；two anchoring cases are compared on the basis of stress，deformation，the shear safety factor of critical section in shallow dam foundation and bolt stress. The reliability and practicality of this research is verified by the comparative analysis between numerical simulation and monitoring data. This research has provided a reliable basis for the decision-making.

The interaction between rock joints and cylindrical waves，which frequently occurs in mining and underground construction，is crucial in rock engineering. Based on the conservation of momentum at the wave fronts and the displacement discontinuity method，quantitative analysis of interaction between incidently cylindrical longitudinal-wave(P-wave) and a linear elastic rock joint is carried out. The wave propagation equation is accordingly deduced. Due to the geometrical spreading，reduction of the wave energy at the wave front is analyzed. For the normal impacting and oblique impacting of the incident wave，the transmission and reflection coefficients obtained from the derived wave propagation equation agree very well with the results from the existing method. Then parametric studies are carried out to investigate the effects of the wave source distance，the density of explosion and the incident waveforms on wave propagation across a jointed rock mass.

Fault-rupture zone F2–1 of Guanjiao tunnel has done a series of research on optimizing support structure design of tunnel in fault-rupture zone. Displacement，pressure of surrounding rock，stress in the steel frames and axial force of rock bolts were obtained by monitoring in the section with original design scheme. The result indicates that construction process has significant effect on support structure；the steel frame stress exceeded steel strength；the distribution of surrounding rock pressure is uneven；the rock bolts do not work effectively. It is shown that the original support scheme could not meet the safety requirements；and it should be modified in time. By a comprehensive analysis of monitoring data，some optimizing methods such as increasing frame steel strength level，temporary supports，small pipe grouting at the side wall，etc. have been used in construction；and their feasibility also be verified by numerical analysis with software FLAC3D. From feedback of field implement and monitoring result，the effect of optimizing method is significant. These research results can provide theoretical basis and underlying data for support scheme in the fault-rupture zone.

Determination of reasonable coal pillar width is key for ensuring stability of surrounding rock of fully mechanized caving roadway driving along next goaf. Taking track roadway of 11302 workface in Zhaolou colliery as the engineering background，a new side abutment pressure monitoring method was proposed；and the reasonable coal pillar width was determined by using the method of field stress monitoring and numerical simulation. Field stress monitoring and numerical analysis results show that the influence scope of workface side abutment pressure is 50–56 m，and low stress zone width is 12–15 m，considering pillar stress environment，pillar width should not be larger than 7–10 m. Meanwhile，considering being propitious to bolt anchoring，width of coal pillar should not be less than 4 m. Various elements such as coal pillar stability，secondary disaster control and resources recovery were considered comprehensively. Finally，the reasonable width of segment pillar is determined as 5 m. Reasonable pillar width is verified by using large-scale geomechanical model test and field test. Monitoring results show that variation of surrounding deformation along the empty wall is largest，followed by roof and entity wall，floor is least. After roadway driving along next goaf stability，roof to floor convergence is 271 mm；two walls convergence is 359 mm；the effect of roadway surrounding rock is well. Bolts and anchors forces are in their yield range；and set aside a sufficient margin for the recovery period. The results can provide a reference for segment pillar setting in other mines with similar mining conditions.

Based on the mesoscopic heterogeneous characteristics of materials，a two-layered numerical model is simulated to study the stress distribution，fracture propagation and the mechanism of edge fracturing due to shrinkage from even cooling of overall upper layer or cooling temperature passing down over time in two-layered materials. Firstly，the stress state between two adjacent fractures of the model subjected to even cooling with a fractured surface is studied；and the stress in the center between the two fractures is the maximum，with the fracture spacing decreaseing， decreases continuously and the stress state changes from tensile to compression，the critical spacing to layer thickness ratio is approximately 3.0 when fracture saturates. Secondly，two-layered model without pre-existing fractures subjected to two types of temperature loading is studied；one with upper layer temperature cooled evenly to －40 ℃ and the other with surface temperature cooled to －35 ℃ rapidly(temperature shock). The results show that the fracture formations due to the two conditions are in a common mode：the first fracture insertes into the middle of upper layer，new fractures inserte into the middle of existing fractures or fracture to the ends until fracture saturation，rather differences are that in the overall even cooling model fractures initiate not only from the surface，but also from the middle，the temperature shock fractures extend always from surface to inside，and with a larger number. This study reproduced the following three stages under cooling shrinkage：micro-fracture initiation，fracture propagation，and fracture saturation；it also shows the process of heat conduction under thermal shock，by comparing results under two temperatures conditions. Finally，the paper introduces that using material with better temperature conductivity would help to reduce surface fractures in road structure.

In light of that the periodical temperature changing leads to mechanical properties deterioration of rock bolts during the snowmelt period in spring，the relationship between bearing capacity of rock bolts and freeze-thaw cycles was studied. The freeze-thaw cycling experiments were conducted first for rock bolt specimens under different freeze-thaw cycles；and then the pull-out experiments were carried out. The displacement，stress and failure load of bolt，stress of rock，shear strength at the bolt-grout interface were investigated；the failure mode and main destruction factor under freeze-thaw conditions were studied with load transfer mechanism. It is shown that the elastic modulus and strength of mortar decreases along with the increase of freeze-thaw cycles；the mortar near the loading end splits ahead of time and accelerates load transferring to the inside of bolt；the internal stresses of bolt and bond increase. The ultimate bearing capacity of bolt decreases while the deformation of bolt increases under freeze-thaw conditions；the inflection point in load-displacement curve and horizontal segment in slipping curve of bolt will appear in advance along with the increase of freeze-thaw cycles.

The brine curtain freezing cannot form a closed frozen wall in inclined shaft because of flowing water in the ground may take away some cold energy. The method of liquid nitrogen freezing was used to strengthen the brine curtain freezing. Conclusion are drawn through analysis of soil temperature distribution data which was gained in the process of freezing construction. Firstly，mixed states of nitrogen gas and liquid nitrogen appeared in freezing pipe when the pipe export temperature is lower than －100 ℃. Opening holes on the liquid nitrogen supplying tube can affect the distribution of liquid nitrogen. As a result it may affect the freezing effect. Secondly，due to flowing water may take away some cold energy；the difference in the expansion speed of frozen soils is larger between pre and post the time that the closed frozen curtain was formed. And the flowing water can affect the temperature distribution of frozen wall. Thirdly，the frozen wall with high temperature gradient were uneven because of the low gasification temperature of liquid nitrogen. The termination of liquid nitrogen supply reduces the temperature gradient in the frozen wall. The soil temperature near the freezing hole rises faster than far away from the freezing hole after the freezing stopped. The research results indicate that the reinforcement freezing can effectively block flowing water by mean of the frozen wall formed by liquid nitrogen freezing. The problem can be solved that the closed curtain cannot be formed using brine curtain freezing.

After the suitability of some previous model for estimating hydraulic conductivity of rock mass，a new model was proposed considering the hydraulic characteristic of water sealed underground storage caverns. Four geological parameters including rock quality designation(RQD)，rock mass integrity designation(RID)，aperture designation(AD)，and lithology permeability designation(LPD) were adopted for establishing the estimated RMP model according to the double packers test data of Yantai LPG underground storage caverns. Then the hydraulic conductivity of 277 sections of rock mass of 14 boreholes in the area of Qingdao water sealed underground storage caverns were estimated by the RMP model. The results indicate that the rock mass in the study area has much randomness of spatial distribution；and 57.04% of the conductivity are between 10－4 m/d and10－3 m/d. The study result has some theoretical significance and engineering value for water curtain system design and evaluating water sealed effectiveness.

To investigate the characteristics of rock specimen under static cyclic loading and repeated dynamic impact，comparative tests are carried out on rock rigid test machine and SHPB device respectively，and the stress-strain relationships are also obtained respectively. It is very difficult to obtain the relationships of rock under repeated impact. Compare the relationships of specimen under two types of loading，except strain ratio effect，there are so many similar characteristics between them. Firstly，the damage process is progressive，which includes yield，crack and broken steps. Secondly the stress-strain relation profile can be classified as elastic，harden，soften and residual part. Lastly the bearing capacity and modulus are gradually decreased after maximum point. The comparative experimental investigations illustrate that the rock mechanical properties under repeated dynamic impact can be approximately made out through the results of static cyclic loading.

For knowing the radial gas seepage characteristics in coal around hydraulic borehole，isothermal desorption experiment and radial gas seepage experiment of drying coal sample，liquid water wetting coal sample and high pressure water injection coal sample after methane adsorption，produced by the outburst coal from Qingdong mine，were carried out by a self-developed test system of radial gas seepage. The results show that：(1) At the same balanced gas pressure，the adsorption capacity of high pressure water injection coal sample is higher than that of drying coal sample，which are significantly higher than that of liquid water wetting coal sample. (2) Adsorption capacity of liquid water wetting coal sample decreases with the increase of moisture content；and the relationship between adsorption capacity and moisture content can be described as logarithmic function；the fitting function of the relationship between the coefficients and adsorption gas pressure is obtained. (3) At the same overburden pressure，the permeability of high pressure water injection coal sample is significantly higher than that of drying coal sample；the permeability of liquid water wetting coal sample is slightly lower than that of drying coal sample；the permeability of liquid water wetting coal sample decrease with the increase of moisture content；and the trend is particularly significant in low gas pressure stage. Based on the results of test，effect mechanism of water on the radial gas flow characteristics is analyzed；it is pointed out that the coal gas around the hydraulic drilling flows through the original desorption and seepage area，pressure water inhibitory desorption and seepage area and liquid water natural wetting coal desorption and seepage area.

Frost heave is assumed to be caused by the formation of ice lenses in a freezing soil. The formation of ice lenses is governed by the Clapeyron equation of thermodynamics and relies on the existence of a frozen fringe between frozen and unfrozen zones. Both unfrozen water and ice co-exist in pores of the frozen fringe. The suction at water-ice interface is the driving force for water flow that feeds the growth of ice lens. The initiation of a new ice lens is governed by a simple effective stress concept. Then a simple frost heave model is presented. The frost heave model contains only a few soil parameters and can be used to compute frost heave and frost penetration in stratified soil profiles. The second part of the paper illustrates the application of the frost heave model in assessing the frost susceptibility of different soils. It is shown that the frost susceptibility of a soil must be assessed together with environmental conditions such as overburden pressure，temperature gradient，cooling rate and the depth of groundwater table. A soil that is only mildly susceptible to frost according to classification can still generate a significant amount of heave or heaving pressure under favourable environmental conditions.

The determination of the face supporting pressure has been one of the key problems in tunnelling engineering. This paper presents a discussion in depth on six different calculating models of the face supporting pressure. Based on the characteristics of clayey soil，the famous Horn?s silo model was modified and the calculation equation on clayey soil，which considers the soil arching effect，was successfully derived. Taking Qianjiang tunnel for example，the calculating results by seven different face supporting pressure methods were analyzed；and their applicability was investigated as well. Detailed discussion on the choosing of calculation parameters was given；so as to provide reference values for similar projects.

Based on the elastic wave theory，summarizing the dynamic analysis model of rigid retaining wall，the first-order differential equation of the differential volume element is established by horizontal slices analysis method. And then，a time-frequency analysis method of seismic active earth pressure of rigid retaining wall is proposed. The reasonability of this method is verified by the results of shaking table test. The frequency of seismic wave has an predominate effect on critical rupture angle of filling earth，the resultant force of the seismic active earth pressure and the application point of resultant. The results are as follows. With the increase of the peak ground acceleration(PGA)，the critical rupture angle of filling earth decreases，the resultant force of seismic active earth pressure increases，and the application point of the resultant is gradually move up；with the increase of the frequency of input wave，the critical rupture angle and the resultant force of seismic active earth pressure are distributed in the shape of saddle and the handstand saddle；and they achieve the maximum value when the frequency of input wave is the same as the natural frequency of rigid retaining wall；but the application point essentially is unchanged；if the rigid retaining wall is designed according to the rules，the emergency capacity of rigid retaining wall will be reduced. At last，this method not only considers the effect of three factors of the seismic wave(PGA，frequency and duration) on the seismic earth pressure of reinforced retaining wall；but also provides some valuable references for the time frequency seismic design of the other retaining structures.

Undrained and constant shear drained(CSD) tests were conducted on loose Toyoura sand using high-precision variable confining pressure triaxial apparatus，which can maintain the deviator stress constant，more reliable results can be obtained from this study. Based on the test results，it can be concluded that the specimens of the same void ratio under different effective stresses have the same instability line，but the instability line slope of sand with the same effective stresses decreases gradually along with the increase of void ratio and tends to be stable. The instability can occur under completely drained conditions，instability as defined in this paper refers to a behavior in which large plastic strains are generated rapidly and continuously，and the axial strain and volumetric strain develop rapidly. In the previous CSD studies axial force were maintained constant；the decrease of the deviatoric stress during the process of test may affect the judgment of the instability；this may be the important reason for the researchers hold different conclusions. The instability occurring under drained conditions is different from that observed under undrained conditions. The differences and similarities between the two types of instability were elaborated. It can be included that instability of undrained tests and CSD tests occur on the similar stress ratios for a given void ratio of specimens. The test results in this study provide a more powerful evidence for the research of instability under drained condition；and they also can be used to analyze the failure mechanisms of granular soil slope.

The rock stratum at pile tip is prone to punching failare for pile foundation in karst region. The Hoek-Brown nonlinear rock strength criterion has been introduced according to the characteristics of rock mass in the karst region；and then the shear stress of quadratic parabolic expression was obtained. The work-energy equation of punching failure body was established using limit analysis method. Then the generatrix equation of punching failure body was obtained through the variational extremum principle. Furthermore，the calculation formula of safe thickness for the rock stratum anti-punching failure was obtained by differential equation. Combined with the practice of pile foundation in karst area，the value range of main resistant punching shear safety thickness factors affecting were analyzed. Parameter analysis shows that：(1) The top and bottom diameter ratio d1/d of punching failure body decreased nonlinearly along with the increase of RMR value；in other words the bottom conical rotor diameter of punching failure which formed by the good karst roof of rock mass quality is small. Conversely，the greater the diameter at the bottom of the body of revolution. (2) According to the different d1/d and RMR values，the ranges of initial punching angle is between 24°–42°. (3) The ratio of thickness to diameter h/d decreases nonlinearly along with the increase of RMR. That is to say the better the rock mass quality，the smaller the safe thickness. When the rock mass quality is good(RMR＞65)，the safety thickness h/d is lower than 2.5.

Based on monitoring of ground temperature in a typical roadbed-culvert transition section，the ground temperature regime and its temporal and spatial development，along with its impact on roadbed stability was analyzed. The results show that，the maximum depth of seasonal freezing in the roadbed of transaction is about 2 times which in the natural ground because of the existence of culvert. The starting times of freezing and thawing process above and below the culvert are earlier than that behind the culvert wall. As the culvert performs somewhat as a ventilation duct，the temperature difference caused by the sunny-shady slopes is weaken. The culvert has a significant impact on the ground temperature of the roadbed around it，showing as significant increase of temperature changing amplitude in the fillings above the culvert and behind the culvert wall. Above all，the works of monitoring and analysis of the freezing characteristics in roadbed-culvert transition section can provide references for the selection of roadbed filling material and foundation treatment below the culvert.