The Large Deformation Engineering Analysis System (LDEAS) is a specialized finite element software designed for analyzing large deformation mechanics, supporting design, and evaluating stability in deep soft rock engineering. The first version of the software, LDEAS 1.0, was developed in 2007, and its main features include: (1) the capability to perform both polar and additive decomposition analyses for large deformations, as well as the ability to solve three types of nonlinear problems—geometric, physical, and contact nonlinearities; (2) the inclusion of rock mass, joint, and support structure elements, enabling calculations for initial in-situ stresses and dynamic simulations for construction and support; (3) the development of the computation program via the Finite Element Program Generator (FEPG) based on low-code programming technology. To address the limitations of the first version and enhance the software, development of the second version, LDEAS 2.0, commenced in 2020. The main improvements and upgrades encompass three key aspects: (1) the introduction of the NPR bolt/anchor element and an implicit damping iteration algorithm for the renewal of elastoplastic stresses, enriching the variety of support structure elements and improving convergence and iteration speed for elastoplastic calculations; (2) an upgrade of the source code for the finite element computing program from Fortran to C language, enhancing fluency, efficiency, and readability; (3) the development of a new integrated interactive user interface and the inclusion of parallel computing, significantly improving user experience and the efficiency of large-scale computations. Test examples and typical engineering cases have validated the correctness, reliability, and practicality of LDEAS 2.0. The upgrades and development of both versions of LDEAS facilitate comparative studies of two major finite deformation theories and investigations of the rock-bolt coupling effects of NPR bolts/cables, providing reliable software for research on deep rock mechanics issues in China, which holds significant theoretical and engineering application value.

Restricted by the significant impact of the “three-high” geological environment (high ground stress, high osmotic pressure, and high ground temperature) on the quality of surrounding rock and the construction process, current research faces three core challenges: (1) Traditional surrounding rock classification methods are often ill-suited for high-energy geological environments; (2) The mechanism of the “three-high” coupling effect on the mechanical properties of surrounding rock is complex and difficult to elucidate; (3) The accuracy of obtaining in-situ surrounding rock parameters in deep regions is inadequate. This paper summarizes the current research status and developmental trends of surrounding rock classification and parameter acquisition methods under the “three-high” geological environment, and proposes directions for future research and development. Overall, research on surrounding rock classification and parameter acquisition methods is progressively moving towards integration, dynamization, and intellectualization, with key developmental trends manifested in the following aspects: (1) There is an urgent need to establish a multi-field coupling surrounding rock classification system that is adapted to the “three-high” geological environment. The coupling effect of the “three-high” geological environment significantly influences the mechanical properties, deformation characteristics, and permeability of surrounding rock, directly affecting the establishment of classification systems tailored for various construction methods. It is essential to integrate geomechanical parameters with real-time monitoring data and employ machine learning technologies to accurately assess the stability, excavability, and construction risks of surrounding rock, thereby meeting the construction requirements of both the drilling and blasting method and the TBM method. (2) There is an urgent need to develop dynamic methods for determining surrounding rock mechanical parameters. Methods for determining these parameters in high-energy geological environments must fully consider the dynamic feedback mechanisms and actively incorporate advanced technologies such as deep learning and intelligent identification to update classification results and construction strategies in real-time. (3) There is an urgent need to construct a multi-field coupling parameter acquisition model. Efforts should focus on transitioning from empirical judgment to theoretical models, establishing constitutive relationships for obtaining surrounding rock parameters based on high-energy geological environments, and further developing cross-scale and multi-source information fusion methods to improve parameter accuracy. In the future, it is crucial to address the bottlenecks in in-situ testing and dynamic feedback technologies for deep surrounding rock, and to establish classification standards for surrounding rock that are suited to high-energy geological environments, thereby providing theoretical support and technical guarantees for the safe construction of deep engineering projects.

To meet the intelligent control requirements for curtain grouting in limestone dam foundations, this study proposes a dynamic prediction method that integrates Grouting Energy Intensity (GEI) with machine learning, aiming to enhance process precision and adaptability in complex karst strata. Utilizing field data from the Dehou Reservoir and the Dongzhuang Water Control Project, a grouting database was established, incorporating key parameters such as grouting pressure (P), flow rate (Q), and Lugeon value (q). A P-Q time-series prediction model was developed using machine learning algorithms to forecast future grouting parameters dynamically. The results indicate that the incorporation of GEI significantly enhances the model?s coefficient of determination (R2). Additionally, a four-level rock mass permeability classification system based on Lugeon values and unit cement consumption was constructed, facilitating intelligent parameter matching and adaptive process control. This research offers a practical technical framework for intelligent construction and quality assurance in curtain grouting within karst regions.

To enable experimental simulation of roadway rockburst induced by fault slip, some experimental principles were distilled based on rockburst process analysis. A large-scale experimental system for simulating roadway rockburst induced by fault slip was developed. The key functions and performance of the system were verified, and physical experiments were conducted to reproduce the phenomena of roadway rockburst induced by fault slip, thereby validating the system?s feasibility in simulating such dynamic events. The results show that: (1) A large-scale experimental system for roadway rockburst induced by fault slip is developed, with model dimensions of 3.0 m×1.5 m×1.5 m. The system features three-directional and four-surface loading capabilities, a maximum loading capacity of 20 MPa, and a loading precision of 0.15% F.S. The system has the function of rapid shear slip for faults, applicable to fault dip angles of 45°–90°. The main reaction frame innovatively adopts a concave-convex interlocking structure connection, achieving high overall stiffness (with a deformation of less than 3 mm under full load). (2) A dense array loading technique suitable for ultra-large-scale models under ultra-high stress is proposed. A compact array loader is invented, employing an embedded cylinder chamber and a shared wall design, enabling efficient multi-point and small-area uniform loading within limited space. This significantly improves load transfer effectiveness across large models. (3) A differential top-bottom coordinated loading method is developed to induce fault activation and slip in the model?s movable zone, where the bottom energy storage-loading is used for rapid retraction, and the top energy-storage loading is used for active follow-up loading. The minimum fault slip time can reach 6 s (slip amount 50 mm). (4) A fault-slip rockburst testing method is proposed, in which critical loading of the roadway is followed by fault activation and slip. During the fault slip process, seismic wave propagation is monitored, and two large-scale burst failures occur in the roadway, reproducing the complete chain process of “fault slip to generate seismic wave-wave propagation-seismic wave inducing roadway rockburst”. This study provides a robust experimental platform for investigating the mechanisms and mitigation strategies of roadway rockburst induced by fault slip.

Building upon research into the effects of thermal disasters and their geological genesis, this study addresses the prevention of thermal disasters in tunnels located within geothermal anomaly zones. To overcome the limitations of conventional single-approach engineering solutions, a novel technical framework was developed, encompassing disaster source identification and control measures. This framework is guided by the methodology of “disaster-pregnant mode analysis, hazard-causing structure identification, process risk assessment, and control intervention.” First, the geological conditions, disaster dynamics, and precursor characteristics of tunnel thermal disasters were analyzed, leading to the identification of four disaster-pregnant modes: convective, conductive, diffuse, and diffuse-conductive composite. Second, recognizing that regional-scale geothermal features dictate the magnitude of hazards, regional-scale hazard structure identification techniques were established through regional geothermal field analysis and geological-geothermal coupling relationships, facilitating the optimal selection of low-temperature corridors. Third, acknowledging that tunnel-scale hazard structures determine disaster locations, collaborative geological-geothermal investigation techniques that integrate geochemical tracing, comprehensive geophysical exploration, and drilling were proposed for the survey-design phase. This approach enabled static risk assessments through the preliminary identification of thermal convergence features, including thermal recharge, high-temperature sections, and thermal phenomena. Fourth, to target potential high-temperature zones, construction-phase multiparameter tracking techniques were introduced to monitor borehole rock temperature, hydrochemical characteristics, and gas composition/concentration. These techniques supported dynamic risk assessments and enhanced the targeted identification of thermal convergence characteristics such as thermal intensity, scale, and severity in high-geothermal sections. Finally, multidimensional control technologies were formulated to address various thermal effects, encompassing ventilation, hygrothermal regulation, heat resistance measures, surrounding rock reinforcement, and concrete composite modification. This culminated in a tripartite synergistic prevention strategy that integrates heat source blocking, environmental control, and structural protection. Future research directions were also outlined. The established technical framework offers a novel system for thermal disaster prevention, providing guidance for safe tunnel construction.

Addressing the limitations of current research on tunnel thermal disasters, which primarily focuses on managing high rock temperatures and ambient temperatures during construction while neglecting heat source mechanisms and accompanying disasters such as high-temperature water inrush and harmful gases, this study systematically deconstructs the formation mechanisms and disaster effects of tunnel thermal disasters by constructing a novel cognitive system termed “heat source-gas source-response-disaster.” Firstly, based on thermal phenomena observed in geothermal anomaly zones and extensive engineering practices related to thermal disasters, tunnel thermal disasters are redefined to collectively encompass high rock temperature, high-temperature water, and harmful gas inrush. Secondly, through a statistical analysis of 87 global cases of tunnel thermal disasters, thermally-induced disasters in geothermal anomaly zones are classified into five types: high rock temperature, hazardous gas, high rock temperature combined with high-temperature water inrush, high rock temperature combined with hazardous gas, and high rock temperature combined with both hazardous gas and high-temperature water inrush. This classification reveals a strong correlation with surface thermal anomalies and the formation lithology. Thirdly, the effects of tunnel thermal disasters are systematically categorized, illustrating their detrimental impacts on the tunnel’s temperature and humidity environment, exacerbation of surrounding rock deformation and failure, induction of cascading failures in support structures, and triggering of multi-dimensional gaseous disaster cascades. Building upon this, the Qinghai—Tibet Plateau is examined as a case study to investigate the origins, sources, and conduction mechanisms of heat and gas in typical geothermal anomaly zones. This establishes a theoretical paradigm for the synergistic genesis of thermal disasters, involving crustal, mantle, or crust-mantle heat and gas generation, coupled with tectonic heat and gas conduction. Finally, the reliability of the research findings is validated through an analysis of a typical tunnel thermal disaster case. This study provides a theoretical foundation for further exploration of disaster-prone patterns, identification of hazard structures, and formulation of prevention and control measures for tunnel thermal disasters.

Toppling failure is a typical type of disaster associated with rock slopes. The deformation behaviors and mechanisms underlying the evolution of rock slope toppling are complex, influenced by adverse geological conditions and external loads. Investigating the deformation characteristics, failure modes, and disaster mechanisms of rock slope toppling, as well as proposing methods for stability evolution, are urgent issues in slope engineering. Approximately 220 cases of toppling slopes in China have been collected, and the regional distribution of these cases is presented. The relationships between toppling failure and several key factors, such as slope height, slope angle, terrain obliquity, and lithology, are thoroughly analyzed. Building on existing classification methods for rock slope toppling, a four-level classification method is proposed based on the tendency relationship between the dominant discontinuity and the slope, the dominant or subordinate status of toppling deformation, the deformation characteristics of the toppling body, and the combination of toppling strata. The deformation behaviors and failure mechanisms of typical toppling types, including block toppling, flexural toppling, and composite toppling, are revealed through a combination of physical model tests and numerical simulations. Systematic presentations of stability analysis approaches, including the G&B method, equivalent continuum method, Liu method, cantilever beam method, and composite analysis method, are provided, along with discussions on their limitations and evolving trends. This research is expected to serve as an important reference for theoretical studies and engineering practices related to rock slope toppling.

Seepage in fractured rock masses is widely encountered in many important engineering fields such as hydropower, civil and transportation infrastructure, energy and mining, and underground disposal repositories. It represents one of the key factors constraining the construction and long-term operation of such projects. As engineering projects advance towards environments characterized by high water heads, great depths, and strong disturbances, conventional models based on linear flow laws have become inadequate for accurately describing seepage behaviors. Nonlinear seepage effects have become increasingly prominent, manifesting as inertial non-Darcian flow at high Reynolds numbers, multiphase nonlinearity in the presence of multiple fluids, coupled nonlinearities arising from interactions among seepage, stress, and chemical processes, as well as boundary- induced nonlinearities under complex boundary conditions. Although significant progress has been made in experimental observation, mechanistic modeling, and numerical methods related to nonlinear seepage, several challenges remain. These include difficulties in conducting in-situ experiments under high-stress and high- pressure conditions, the complexity of quantifying the effects of coupled processes, the empirical nature of model parameter identification, and poor convergence in numerical simulations. Focusing on these theoretical and applied challenges of nonlinear seepage in fractured rock masses, this paper systematically reviews and elaborates on key issues such as the underlying mechanisms, theoretical models, and parameter identification related to non-Darcian flow regimes, multiphase flow effects, coupled processes, and boundary nonlinearities. Furthermore, simulation methods and control techniques for nonlinear seepage in fractured rock masses are introduced. This paper highlights the vital role of nonlinear seepage theory in improving prediction accuracy, enhancing the reliability of safety evaluations, and supporting proactive engineering control. This is demonstrated through engineering applications, including seepage control and assessment in high-pressure water conveyance tunnels, modeling and evaluation of three-dimensional drainage systems in hydropower projects, and long-term performance evolution analysis of seepage control systems. Future research should aim to establish unified theoretical models and highly robust numerical methods, integrate nonlinear seepage analysis throughout the entire engineering design process, and develop intelligent seepage control systems that integrate monitoring, identification, and regulation. By deeply integrating multidisciplinary knowledge with artificial intelligence technologies, a transition from state assessment to proactive control can be achieved.

As the foundation for regional landslide risk assessment, landslide susceptibility prediction (LSP) is a prominent and challenging topic in global landslide disaster prevention and control research. This paper systematically reviews critical issues in LSP, including model selection, identification and integration of conditioning factors, determination and classification of prediction units, methods for selecting non-landslide samples, optimization of the landslide-to-non-landslide sample ratio, assignment of label values to non-landslide samples, and evaluation methodologies for landslide susceptibility results. The literature review indicates that tree-based models, such as Decision Trees and Random Forests, demonstrate superior performance. The selection and integration of conditioning factors should adhere to principles of comprehensive typology and clear physical significance. Prediction units can be defined through multi-scale segmentation of slope units. Non-landslide samples should preferably be randomly selected from areas characterized by very low or low susceptibility. The optimal ratio of landslide to non-landslide samples can be established through experiments under various conditions. Specific small probability values should be assigned to non-landslide samples. Evaluation of LSP results necessitates a comprehensive consideration of multiple metrics, including ROC accuracy, prediction rate accuracy, and the mean and standard deviation of the susceptibility index. Furthermore, to enhance the accuracy of LSP and validate the cross-regional engineering applicability of the semi-supervised imbalanced theory, this study pioneers the application of the Random Forest model based on this theory in Anyuan-Xunwu County, Jiangxi Province. Experiments were conducted under various scenarios, involving different ratios of landslide to non-landslide samples (ranging from 1:1 to 1:260) and varying label assignments for non-landslide samples. Results indicate that as the ratio increases from 1:1 to 1:180, both ROC accuracy and prediction rate accuracy improve gradually from 0.905 and 0.898 to 0.957 and 0.937, respectively. However, no significant improvement is observed in either metric once the ratio exceeds 1:180. Consequently, the optimal ratio of landslide to non-landslide samples is established at 1:180. Additionally, this study collects data from six landslide events that occurred between 2022 and 2024 to validate the results obtained from the 1:180 ratio. The validation reveals that all six landslides are situated in areas of very high or high susceptibility. This not only confirms the effectiveness and engineering applicability of the semi-supervised imbalanced theory in the mountainous and hilly regions of southern Jiangxi but also provides new insights and technical support for the precise prevention and control of landslide risks.

The stability of the compressed air energy storage (CAES) cavern is influenced by ground stresses during the construction phase and by cyclic high internal pressure (≥10 MPa) during the operational phase, resulting in different mechanical responses of the surrounding rock during the unloading and loading phases. This study investigates the stress paths of the CAES cavern from the perspectives of stress evolution and damage modes throughout both construction and operational phases. The findings indicate that during the excavation phase, active support technology significantly reduces deformation by adjusting the principal stress field of the surrounding rock, particularly in low-strength rock formations. Additionally, the load transfer effect decreases the burden on initial supports, such as steel arches. In the operational phase, the high internal pressure causes the sequence of principal rock stresses to shift, with radial stress increasing to the maximum principal stress and circumferential stress transitioning to the minimum principal stress. When exposed to hydrostatic pressure, characterized by low local stress and high rock strength, the surrounding rock at the tunnel wall may experience tensile failure during the high-pressure gas storage stage; otherwise, shear failure will occur at the tunnel wall. When the lateral pressure coefficient ( ) is less than 1, shear failure occurs in the surrounding rock at the side walls. In cases where the lateral pressure coefficient is particularly low, tensile failure may still happen at the arch crown. Conversely, when exceeds 1, shear failure is observed in the surrounding rock at the arch. If the lateral pressure coefficient is notably high, tensile failure may still occur at the side walls. As pressure increases, the area of tensile fractures may subsequently undergo shear failure. Further analysis reveals that conventional grouting and radial bolt systems significantly enhance stability only during the excavation phase. During operation, radial bolts not only lose their reinforcing capabilities but also exacerbate stress concentration in the surrounding rock under compression. In contrast, enhanced circumferential restraint effectively improves the stress state of the surrounding rock. For surrounding rock of good quality and high strength, grouting has limited efficacy in filling fractures. Conversely, grouting measures have been shown to increase the shear strength of formations characterized by low strength. Based on these insights, this study proposes an innovative solution for the stability control of CAES caverns subjected to complex stress paths by forming an anchor network system using crossed diagonal anchors and optimizing the inclination angle of the anchors to achieve a full-cycle tensile state.

 In response to the engineering challenges posed by unclear disaster-causing mechanisms and inadequate control effectiveness for roadway surrounding rock in steeply dipping and extra-thick coal seams, this study focuses on the +400 mB3 roadway in Wudong Coal Mine. A comprehensive research methodology was employed, integrating on-site monitoring, theoretical analysis, numerical simulation, and industrial testing. The investigation examined the evolution and rotation characteristics of the principal stress path under excavation disturbance in steeply dipping and extra-thick coal seams. Additionally, the study elucidated the driving mechanisms behind mining-induced stress evolution, which leads to fracturing in the coal and rock mass, and revealed the mechanism of roadway surrounding rock disasters induced by the coupling effects of the stress field and fracture field. The results indicate that the surrounding rock in the lower section of the roadway is significantly influenced by mining activities, undergoing a stress evolution process characterized by ?1 loading followed byσ3 unloading. The principal stress axis exhibits spatially differential rotation, deviating from its initial orientation. Notably, the degree of stress rotation is most pronounced in the roadway roof, with rotation angles ranging from 16.7° to 20.8°. Due to the impact of mining activities, the stress level within the coal and rock mass reaches its strength threshold, leading to the formation of mining-induced fractures. The angle of stress rotation determines the predominant propagation direction of these fractures, while the presence of the mining-induced fracture field compromises the mechanical integrity and strength of the surrounding rock in the roadway. After the unloading associated with roadway excavation, mining-induced cracks continue to propagate, primarily characterized by Mode I tensile failure. As the inclination angle of these cracks increases, the anti-unloading failure resistance of the coal and rock mass gradually strengthens, resulting in a transition of the failure mode from crack-dominated to matrix material-dominated. The disaster-causing mechanism of the roadway surrounding rock can be summarized as follows: the orientation of stress rotation governs crack propagation, the formation of a crack network weakens the load-bearing structure, and strength degradation leads to large deformation. Under the coupled effects of the stress field and fracture field, the roadway experiences deformation and failure. To address these challenges, a surrounding rock stability control strategy combining “overall reinforcement with key point strengthening” has been developed for roadways in steeply inclined and extra-thick coal seams. Following the implementation of the reinforcement support, the stability of the roadway?s surrounding rock has been significantly enhanced. The findings of this research provide a solid scientific foundation for the control of surrounding rock in steeply inclined and extra-thick coal seams, as well as in similar roadways.

 Circulating hydraulic fracturing, a flexible transformation method for hot dry rock, is anticipated to reduce reservoir fracture pressure, enhance transformation volume, and ensure efficient and safe storage. This method holds significant promise for the economic and efficient development of hot dry rock geothermal resources. To investigate the evolution and fracture mechanisms affecting the tensile properties of reservoir rock due to cyclic hydraulic fracturing, we conducted cyclic loading-unloading Brazilian splitting tests on granite treated with high-temperature water cooling. Two test conditions were examined: varying heat treatment temperatures (200 ℃, 300 ℃, 400 ℃, 500 ℃ and 600 ℃) and different cyclic load upper limits (peak loads of 65%, 70%, 75%, and 80%). The fracture surfaces were analyzed using scanning electron microscopy. The results indicate that tensile strength initially increases and then decreases with rising heat treatment temperatures but continues to increase with higher load upper limits. The number of cycles leading to fatigue failure decreases as the load upper limit increases, displaying a trend of first decreasing and then increasing with higher heat treatment temperatures. The peak displacement experiences three stages: rapid growth, slow growth, and eventual failure as the number of cycles increases. Notably, when the temperature exceeds 300 ℃, deformation significantly increases, suggesting that granite transitions from brittleness to ductility. Overall, the fracture mode is characterized by failure along the diameter direction. Beyond 300 ℃, the crack mode shifts from a “straight line” tensile crack penetrating the center of the circle to a “curved line” mixed tensile-shear crack deviating from the center. This change is primarily attributed to the substantial softening of mineral crystals and the formation of microcracks due to high temperatures. Furthermore, microstructure analysis reveals that as heat treatment temperature and cycle number increase, the internal crack propagation mode of granite transitions from transgranular to intragranular. Concurrently, micro-damage accumulates, resulting in decreased fatigue strength and increased plastic deformation. Macroscopically, this manifests as a coupling effect of tensile strength attenuation and enhanced fracture ductility. The findings of this research provide theoretical support for the design and construction of cyclic hydraulic fracturing.

In low-temperature environments, the physical and mechanical properties of rocks, as well as their engineering behavior, differ significantly from those at ambient temperature, primarily due to water-ice phase transitions. These differences become more pronounced as the temperature decreases. Considering industry-specific low-temperature classification standards and the environmental conditions of geotechnical engineering, a refined low-temperature zoning framework tailored to geomechanics is proposed, defining the threshold for “deep low temperatures” and further subdividing it into “extreme low temperatures” and “ultra-low temperatures.” Based on findings from laboratory experiments, theoretical analyses, and numerical simulations, this study provides a systematic review of the physical and mechanical properties of rocks under deep low-temperature, with a particular focus on the temperature-dependent evolution of key parameters such as porosity, elastic wave velocity, thermal conductivity, elastic modulus, and mechanical strength. Furthermore, by employing the thermo-hydro-mechanical (THM) coupling models, the mechanisms by which frost heave effects, thermal stress distribution, and water migration contribute to rock damage are analyzed. Numerical simulations reveal the coupled evolution characteristics of the temperature, stress, and seepage fields, as well as their underlying roles in the accumulation and progression of rock damage. Additionally, key scientific and technological challenges associated with deep low-temperature rock mechanics are examined in the context of engineering applications, such as underground energy storage, liquid nitrogen-based waterless fracturing, polar infrastructure, and deep-space resource extraction. Finally, based on current theoretical advancements, technological developments, and engineering demands, several future research directions in rock mechanics under deep low-temperature conditions are proposed. These include investigations into the micro-scale phase transition dynamics and multi-scale damage mechanisms of rocks in deep low temperatures, the development of non-equilibrium multi-field coupling theoretical frameworks, and the spatiotemporal prediction of long-term rock performance under deep low-temperature conditions.

Rockburst is a dynamic disaster characterized by the sudden instability and violent fracturing of chambers under high-stress conditions, with the critical stress serving as the most pivotal indicator. In this study, the maximum load criterion and the maximum potential energy criterion for the occurrence of rockbursts in chambers were proposed, and the theoretical critical stress formulas for rockbursts in circular chambers under hydrostatic pressure were derived. The discrepancy in critical stress derived from the two discrimination criteria is less than 2%. This study indicated that the critical stress was mainly influenced by uniaxial compressive strength, rockburst energy index, internal friction angle, and support stress. The biaxial isobaric loading experiments were conducted on circular chamber specimens of granite gneiss and basalt with dimensions of 150 mm× 150 mm× 50 mm. The average error between the experimental and theoretical values of the critical stress was 2.53%. Comparative analysis with field cases revealed an average ratio of 0.55 between actual stress and critical stress, prompting subsequent refinement of the formula. The application of the critical stress formula was discussed from the aspects of hazard assessment, prevention design, and safety evaluation of chamber rockbursts.

As cold region engineering expands to higher altitudes and latitudes，the application of fractured rock masses(FRM) in cold region engineering has increased significantly. However，existing  theories in frozen soil mechanics are insufficient to address the engineering challenges in these areas. This study investigates the mechanisms of freeze heave(FH) in FRM under low temperatures and freeze-thaw cycles. Through theoretical analysis，laboratory and field experiments，and numerical simulations，the research explores the formation mechanism and failure patterns of FH pressure in FRM. The study finds that FRM exhibit various FH mechanisms，including volumetric expansion，segregated ice，and mixed FH. The semi-elliptical open fissure mixed FH model provides a better description of these mechanisms. FH in FRM is a complex coupling of thermo-hydro-mechanical processes that involve moisture migration，multiphase heat conduction，and crack propagation. Factors such as fissure structure，saturation，sealing properties，freeze mode，ice-rock interactions and phase transitions significantly influence FH pressure and damage. The primary mechanism of damage in FRM is driven by FH pressure promoting the crack propagation，which is significantly influenced by the characteristics of the fissure and rock mass. Moreover，laboratory and field tests show differences in FH behavior，especially concerning freeze-thaw cycles，crack initiation temperature，and water absorption conditions. Future research should focus on micro- and meso-mechanisms，supported by laboratory and field experiments，to investigate moisture migration and ice-rock interactions. The objective is to solve FH pressure，explore the evolution of fracture networks using numerical methods，and develop an adaptive monitoring and decision-support system for predicting FH failure，integrating artificial intelligence and big data.

Fault stick slip instability can easily induce fault slip rockburst. In order to further explore the stick-slip evolution characteristics of faults with different dip angles and AE and charge induction multi-source precursors，bidirectional friction tests were carried out on syenitegranite with faults with different prefabricated dip angles. The accumulated energy and spectral characteristics of acoustic emission and charge induction signals during fault stick-slip were analyzed，the AE sources were located，and the nonlinear characteristics of AE and charge induction time series were studied based on multifractal theory. Three quantitative indexes(maximum multi-fractal dimension Dqmax，spectral width Δα and multi-fractal parameter Δf(?)) with good correlation with stick slip instability were constructed，and the following conclusions were drawn：(1) With the increase of fault dip angle，the fault failure mode changes from sliding failure along the plane to sliding failure through the plane，which increases the intensity and energy of AE and charge induction signals. (2) The maximum multi-fractal dimension Dqmax and spectral width Δα of the AE and charge induction signals gradually increase with the increase of fault dip angle. The maximum multifractal dimension and spectral width of the AE and charge induction signals can reflect the difference of energy released when the fault stick slip instability or severely damaged. The multi-fractal parameters Δf(?) of AE and charge induction signals are all less than 0 when the fault is instability or severely damaged.，and the critical value of Δf(?) can be used as the prediction index of fault stick slip instability and severe failure. (3) Compared with the AE and charge induction signals generated by shear slip failure along the plane of 34°and 45°faults，the AE and charge induction signals generated by 56°faults through the plane slide failure has lower dominant frequencies. It can be considered that the dominant frequencies of the AE and charge induction signals are related to fracture scale.

The fractures make the thermal-hydro-mechanical(THM) characteristics of rock mass and soil mass obviously different，and the existing frozen soil theory is difficult to solve the freeze-thaw disaster problem of low temperature rock mass. The migration mechanism of fracture water，the heat transfer mechanism of fracture，the dynamic evolution of fracture characteristics and the multi-field coupling of thermal-hydro-mechanical in heterogeneous rock mass are the key to study the freeze-thaw disaster of low-temperature rock mass. In this paper，the research progress of low-temperature rock mass with phase change is analyzed from four aspects： water migration mechanism，heat and mass transport characteristics，physical and mechanical characteristics and THM coupling characteristics. The research results on low-temperature rock mass at home and abroad are abundant，but the heterogeneity caused by fractures and the special characteristics of the THM properties of fractures under the condition of phase change are not fully considered. The mechanism of hydrothermal migration in fracture of low-temperature rock mass has not been proved，and there is lack of large-scale test equipment for studying the THM characteristics of low-temperature fractured rock mass. Although the fracture propagation caused by frost heave has been studied，the dynamic fracture evolution equation considering the whole process of freeze-thaw and the freeze-thaw cycle has not been established. The freeze-thaw disaster of low-temperature rock mass involves hydrothermal migration at the micro-level，fracture evolution at the meso-level and deformation and failure at the macro-level. So far，no THM coupling model has been established which integrates the results of micro-meso- macro. In order to explore the THM characteristics of low-temperature rock mass，the ice-water phase should be taken as the breakthrough point，the discontinuous characteristics caused by fractures should be closely linked，large-scale laboratory equipment should be developed，the mechanism of hydrothermal migration in fractures should be verified，the fracture evolution equation should be derived，the THM coupling model should be constructed，and numerical simulation programs should be developed，to finally realize the simulation of freeze-thaw disasters in low-temperature rock mass.

Prestressed anchor rods exhibited effects on the mechanical properties of intact rock mass and fractured rock mass. Uniaxial compression tests of intact rock mass and direct shear tests of fractured rock mass were conducted under different pretension anchor rod support conditions. Additionally，the crack-changing characteristics inside the rock mass were revealed by acoustic emission. The results of uniaxial compression tests show that compared with unsupported rock mass，the changes in compressive strengths of intact rock mass exhibited unobvious under ultra-low and low pretension supporting conditions，while the compressive strengths were significantly improved by medium and high pretension supporting. The rock mass showed obvious single-inclined plane shear failure under no support and ultra-low to low pretension bolt support conditions. Specifically，as the pretension force of the anchor bolt increased，the failure mode of the anchor rock masses changed from shear failure to tension splitting failure. These failure characteristics aligned with the crack type characterized by the RA-AF value. The results of direct shear tests show that the pretension bolt could enhance the bearing performance of fractured rock mass. The shear strength of fractured rock mass increased with the increase in the pretension force of anchor bolts. The crack evolution mode of anchor fractured rock mass during shear loading was revealed through acoustic emission signal analysis. At the initial loading stage，the proportion of tensile cracks was close to that of shear cracks. As the progress of loading continued，the shear crack became dominant. This work could provide theoretical basis for studying the mechanism of active support and the design of anchor support.

The research on early warning of gradual-change landslides has made great progress，and early warning and prediction have been realized in many cases. But the early warning and prediction of sudden-onset landslides are still impotent. Focusing on the internal and external response relationship between the stress release from the rupture of the internal rock and soil body and the coordinated deformation of the rock body on the slope surface in the evolution of landslides，we study the characteristics of the dynamic change of the stress-sliding force-deformation in order to obtain the precursor information of sudden-onset landslide destabilization. In the process of landslide from static deformation to dynamic slip，the potential slip surface is initially deteriorated by local rupture，and then accelerated by the rate effect after the overall penetration. Thus a parameter deterioration model considering the local rupture and accelerated deterioration of the slip surface is constructed. Based on the vector sum method，the landslide resistance and decline force are calculated，and a time-dependent degradation mechanical model considering the deterioration of the mechanical parameters of the slip zone is established. The model is used to calculate the force and deformation characteristics of the whole process of landslide formation and evolution，revealing the stage characteristics of stress-slip force-deformation in the process of landslide formation. The results show that landslide stress，slip force and deformation indicators show obvious stage characteristics，which can be divided into initial，isokinetic，accelerated and near-slip stages. When the landslide enters the near-slip stage，the sudden drop in slip resistance and stress is earlier than the rapid increase in landslide deformation，which is helpful for early warning and prediction of sudden-onset landslides.

In order to study the dependence of the mechanical properties of fractured hard rocks，including their strength，deformability，failure mode，characteristic of energy dissipation and bursting liability，on fracture distribution and volumetric or areal damage variable，uniaxial compression tests were carried out on limestone specimens with a single fracture，three coplanar and non-coplanar fractures at different inclination angles. The results show that：(1) the elastic deformation is mainly affected by the volumetric damage variable，while the strength is mainly affected by the areal damage variable. For the specimens with a single fracture，the unified Young?s modulus and peak strength increase monotonically with the fracture inclination angle，and the relation between the unified Young?s modulus or peak strength and the component of Oda?s second-order volumetric damage tensor or areal damage vector along the loading direction，can be well fitted with an inverse proportional power function. For the specimens with three coplanar or non-coplanar fractures，both the curves of the unified Young?s modulus and peak strength with the fracture inclination angle are W and V shapes respectively，and prediction for their upper limit and average can be given by the above relations with the component of volumetric and areal damage tensors obtained from the specimens with a single fracture respectively. (2) In general，the fractured limestone specimen may undergone three damage evolution stages，i.e.，initiation and propagation of cracks，formation of macroscopic failure surface(zone) and residual deformation. There are three basic failure modes：split，stepped and blocky failure. (3) Some of the limestone specimens show certain degree ductile characteristics due to the existence of the fractures，namely，their stress-strain curves change from single peak to multi-peaks. For the specimens with single peak stress-strain curve(type I)，the elastic energy accumulated before the peak stress is rapidly transformed into dissipated energy. For the specimens with multi-peaks stress-strain curves(type II and III，multi-peaks during softening and hardening stages，respectively)，the elastic energy accumulated before each peak stress is released and transformed into dissipated energy step by step. Both the unified total strain energy and energy storage limit of the specimen may increase linearly with the unified peak strength，and therefore is inversely proportional to the component of the two damage tensors. and (4) Both the intact and fractured limestone specimens at failure appeared different degrees of bursting phenomena such as particle ejection and making sound. Compared with the elastic strain energy index and bursting energy index，the comprehensive index of elastic strain and bursting energy(the ratio of the elastic strain energy before the peak strength to the total strain energy)，can more reasonably represent the bursting liability of the fractured specimens with multi-peaks stress-strain curve，and coincide very well with the degrees of bursting intensity observed in the test.