Stress is the fundamental driving force causing deformation and damage of the surrounding rock in mining engineering underground spaces. Widespread and highly concentrated stress is a notable feature of mining-induced stress in underground coal mines. The stress field underground in coal mines includes the in-situ stress field，mining-induced stress field，and support stress field，together forming the comprehensive underground stress field. This article discusses the stress evolution characteristics of coal mine surrounding rock and the theory and technology of surrounding rock control，with stress as the main focus. Regarding in-situ stress，based on extensive field measurements of in-situ stress，the distribution characteristics and influencing factors of the underground stress field in Chinese coal mines were detailedly analyzed. Concerning mining-induced stress，a combination of theoretical analysis，numerical simulation，physical simulation，and field monitoring methods were employed. The evolution process of stress in the excavation face and roadway surrounding rock was comprehensively studied from multiple perspectives，and the mining-induced stress evolution characteristics and main influencing factors around the coal mining face were analyzed. In terms of support stress，a series of roadway support test and simulation experiment platforms were independently developed. Systematic tests were conducted on rock bolts and roadway surface protective components under various complex load conditions，and their mechanical response characteristics and failure mechanisms were evaluated. The distribution characteristics and evolution laws of the support stress fields generated by various support methods，both in support itself and in the surrounding rock，were deeply studied. Based on the studies of in-situ stress，mining-induced stress，and support stress，the control mechanisms，design methods，support reinforcement materials，and control techniques of rock surface support，anchoring，modification，unloading，and combined methods were analyzed. Application examples emphasized hydraulic fracturing unloading technology and the synergistic control technology of support+modification+destressing. Underground tests and applications showed that the surrounding rock control technology based on mining-induced stress evolution significantly improved the stability and safety level of the roadway surrounding rock，achieving good rock control effects. Finally，the challenges in the study of underground stress fields in coal mines and the control of roadway surrounding rock were analyzed，and the future trends in surrounding rock stress testing and analysis，and the theory and technology of surrounding rock control were discussed.

With the rapid development of new energy sources，the compressed air energy storage(CAES) underground caverns，which differ from traditional tunnel conditions，face stability issues in the overlying rock mass. The potential instability modes of these shallow-buried tunnel-type CAES caverns urgently need to be studied. Adopting the Mohr-Coulomb strength criterion and based on the ultimate stress field of the rock mass and considering both tensile and shear failure modes，the problem of potential instability modes in shallow buried high internal pressure tunnel-type lined rock caverns is reduced to the initial value problem of a cluster of ordinary differential equations，and the solution method is given. The reliability of the method is verified by comparing and analyzing the results with the physical model test results. In addition，the effects of burial depth，tunnel diameter，in-situ stress ratio and internal friction angle on the instability pattern are investigated，and the results show that the in-situ stress ratio and internal friction angle have a significant influence. The horizontal stress direction is perpendicular to the axis of the tunnel，which is more conducive to the stability of the overlying rock. On the other hand，the influence of the internal friction angle on the instability pattern depends on the in-situ stress ratio. When the in-situ stress ratio is less than 1，the smaller the internal friction angle is，the closer the potential rupture surface is to the horizontal；when the in-situ stress ratio is equal to 1，the internal friction angle has almost no effect；when the in-situ stress ratio is greater than 1，the larger the internal friction angle is，the closer the potential rupture surface is to the horizontal. In view of this，the design of cavern layout，burial depth and diameter should consider both in-situ stress and internal friction angle. Finally，potential failure surface morphology is parameterized in a simple geometric way，and the correspondence between the geometric parameters and the in-situ stress ratio and internal friction angle is given for engineering reference. In terms of failure modes，when the geostress coefficient is small，the potential failure surface exhibits a tensile-shear composite mode，with the tension region located near the cavern wall and the ground surface. When the geostress coefficient is large，the failure mode is primarily shear.

To study the hard sandstone rockburst failure characteristics under high ground stresses and to simulate the damage failure characteristics of the rock mass in that state，a I/II mixed cohesive zone model based on Park-Paulino-Roesler(PPR) potential energy function was established. Through disk-shaped compact tension test and punch-through shear test，the mode I and mode II fracture characteristics of hard sandstone were studied，and the parameters were obtained. Then，a numerical model was established to simulate the rockburst of hard sandstone tunnels under high ground stresses. The stress and energy of the elements in the process of rockburst are tracked to analyze the process and failure characteristics of rockburst in hard sandstone tunnel. The research results indicate that：(1) the shear strength and mode II fracture energy of hard sandstone increase with the increase of the confining pressure. When the confining pressure exceeds 30 MPa，the mode II fracture performance tends to stabilize. (2) When the vertical stress is much greater than the horizontal stress，the hard sandstone tunnel mainly experiences tensile-toppling rockburst in the form of layered spalling or wedge-shaped burst. On the contrary，shear-bursting rockburst characterized by penetrating shear failure in rock mass will occur. When the horizontal stress and vertical stress are both large，the unloading failure mode of rock mass mostly shows the characteristics of tensile-shear composite failure，and the tensile-stripping rockburst mainly occurs.

In order to study the seismic dynamic response law of high arch dams，based on the measured seismic waveform of Dagangshan arch dam with a height of 210 m and a distance of 21 km from the epicenter in the Sichuan Luding MS 6.8 earthquake，the seismic response characteristics and laws are analyzed by time domain and spectrum analysis methods. The results show that under the main shock excitation of the Luding earthquake，the peak acceleration(PGA) of the arch dam along the river is 586.63 cm/s2(#6 dam crest)，and the PGA of the bedrock along the river is 229.18 cm/s2. The acceleration distribution is generally greater than the horizontal and vertical directions，and the dam body is greater than the resistance body on both sides. The dynamic response of the dam is the most significant along the river. As the elevation increases，the dynamic amplification effect gradually increases，and the maximum amplification factor reaches 4.2 times(#6 dam crest).The results of spectrum analysis show that the main frequency of the earthquake is about 1.73 Hz，and the main frequency of the dam above 1 081 m is between 1.52 and 1.75 Hz，which is close to the modal frequency of the dam. This is one of the reasons why the dam has a strong sense of earthquake. Combined with the dynamic response analysis of typical earthquake dams in recent years，earthquakes with large magnitude and far epicenter distance are more likely to stimulate the low-frequency dynamic characteristics of dams. The relevant results can provide reference for post-earthquake dam safety assessment，seismic design and research of high arch dams.

Through conducting the triaxial unloading-induced slip tests of different types of rock structural planes with dry，wet and crude oil interfaces，the effect of interface types on the activation process of rock structural planes was explored，and the correlations between the microscopic characteristics and macroscopic performance of structural planes during the activation process were revealed. The results show that the activation of rock structural plane is divided into three stages，i.e.，stable stage，activation stage and dynamic slip instability stage. During shear sliding of rock structural plane，rock fragments resulting from the shearing and exfoliation of rock structural plane accumulate in the form of bedding，with greater damage observed at the edges of the structural plane compared to the interior. The JRC degradation rate of rock structural plane with dry interface is 62% after the triaxial tests，which is greater than that of dry interface(33.6%) and crude oil interface(30.5%). For the structural plane with dry interface，the asperities on the structural plane are strongly self-locked，and the average slip rate is low(0.13 μm/s) in the stable stage. While in the stick-slip stage，the damage of the asperities on the structural plane is primarily brittle failure with suddenness，which leads to the average slip rate of stick slip reaching 9.7 μm/s，74 times larger than that in the stable stage. For the structural plan with wet interface，the presence of water promotes the occurrence of stick-slip events. During stick-slip，the damage of the asperities is mainly ductile failure，and the slip rate transition exhibits a sharp increase followed by a falling process. The mixing of rock fragment and water during shear slip increases the contact area between the adjacent structural plane，improves the intermolecular adsorption force，and strengthens the friction strength of the rock structural plane. For the structural plan with crude oil interface，a layer of colloidal crude oil is attached to the rock structural plane，which fills the void space on the rock structure surface as ductile gouge layer，weakens the hardness of the surface asperity and reduces the friction strength of the rock structure structural plane. The existence of crude oil also makes the friction strengthening effect of the structural plane and the self-locking effect of asperities weak，and the structural plane is more prone to undergo dynamic slip compared to structural plane with dry or wet interfaces. The interface type controls the increase of friction coefficient and the slip rate at the start of dynamic slip. The friction coefficient of dry，wet and crude oil rock structural planes increased by 5%，11.2% and 0.7% respectively during activation process，and the slip rate at the start of dynamic slip are 1.1 mm/s，0.27 mm/s and 0.023 mm/s respectively. Our research may provide a theoretical basis for evaluating the fault instability of structural plane with different interface types in the oil and gas reservoirs，and have important implications for better understanding the occurrence of extraction induced fault activation.

In order to reveal the influence mechanism of intersecting joints on the dynamic strength and failure mode of rock mass，the dynamic mechanical behavior of rock mass with intersecting joints under different joint distribution forms was studied，considering the angle，penetration degree of intersecting joints，penetration degree of main joints and strain rate，etc. Influenced by the parameters，the split Hopkinson pressure bar(SHPB) impact test was carried out，and a high-speed camera was set to record the failure process of the sample in real time. The dynamic mechanical properties，energy dissipation and crack initiation-failure laws of the cross-jointed rock mass were analyzed. The research results show that：(1) with the increase of joint angle and(main) joint penetration，the dynamic compressive strength and elastic modulus of cross-jointed rock mass show a downward trend，and there is an obvious rate correlation. (2) The main cracks of the sample always occur along the main joint surface，and change from wing cracks to wing cracks and coplanar cracks with the increase of penetration. The crack initiation and connection modes are different in different joint distribution forms. The main three failure modes are splitting tensile failure along the loading direction，tensile failure along the prefabricated joint surface and tensile-shear composite failure along the prefabricated joint surface. (3) With the increase of the penetration and included angle of the main joints，the length of the joint surface of the incident wave front increases，the transmission energy through the joint surface decreases，and the damage degree of the sample increases，resulting in a sudden increase of the dissipated energy.

With the continuous warming of climate，thermal and melting degradation of perennial frozen layers in the Qinghai—Tibet Plateau，Alps and other high altitude areas leads to a large number of rock mass instability disasters. To study the “softening effect” of mechanical properties of frozen ice-sandwiched rock mass upon thawing is a key premise to reveal the thermal melting instability mechanism of frozen rock mass. In this paper，a series of uniaxial compression tests were carried out on frozen rock mass with different crack angles and melting temperatures，and acoustic emission and high-speed photography methods were used to monitor the failure process. The results show that：(1) the uniaxial compressive strength of the samples decreases first and then increases with the increase of the crack angle θ. (2) The uniaxial compressive strength of the sample decreases gradually with the increase of temperature，which can be divided into three stages： rapid reduction stage(－20 ℃–－6 ℃)，fluctuation decline stage(－6 ℃–－1 ℃) and strength plunge stage(－1 ℃–0 ℃). (3) The samples with different crack angles have three failure modes：the ice layer is crushed as a whole，which is brittle failure. The obvious plastic deformation occurs after the ice is broken，which is ductile failure. Cracks in the middle of the ice layer extend to the upper and lower ice-rock interface，and relative slippage occurs along the interface of the upper and lower rocks. The whole sample is broken，which is brittle failure. (4) Under the condition of thermal melting，the failure mode of fractured ice-sandwich rock mass can be divided into two types：the cracks in the middle of the ice layer expands to the upper and lower ice-rock interface，the relative slip of the upper and lower rocks occurs along the interface，and the whole sample is broken(－20 ℃≤T≤－6 ℃ or －1 ℃≤T≤0 ℃). Obvious plastic deformation occurred after the ice layer was broken，and no whole fracture occurred(－6 ℃＜T＜－1 ℃). Through theoretical analysis，the influence mechanism of crack angle on the compressive strength of fractured ice-sandwich-rock mass is mainly that the failure mode of fractured ice-sandwich-rock mass changes from vertical splitting failure of ice sheet to shear failure along ice-rock interface and shear failure along ice layer with the increase of crack angle. Based on the results of NMR one-dimensional imaging，the content of unfrozen water at the ice-rock interface increases continuously during the heating process，that is，the strength of the ice-rock interface decreases continuously，which leads to the temperature dependence of the strength variation of fractured ice-rock mass.

Engineering practices have demonstrated that rock masses containing structural planes exhibit wider ranges，higher frequencies and greater risks in terms of engineering safety in relation to rockbursts. Consequently，investigating the mechanism and failure characteristics of such rockbursts is of paramount importance，in order to prevent，control and treat deep-buried rockburst disasters. Based on the typical failure mode of rockbursts in tunnels for rock masses containing structural planes，laboratory true-triaxial tests were conducted on granite，limestone and sandstone specimens with structural planes. The load-displacement relationship，acoustic emission，ejection acceleration，and high-speed photography techniques were utilized to investigate the characteristics and failure mechanism of the rock masses under different joint dip angles and lithologies. The experimental results demonstrate that the failure mode of rock masses containing structural planes is significantly influenced by the dip angle(i.e.，the angle between the maximum principal stress plane and the structural plane) and the parameters(such as internal friction angle and cohesion) of the structural planes. In particular，when the dip angle of the structural plane is small，the surrounding rocks can undergo strain-type splitting failure. With increasing dip angle，the rock mass exhibits a characteristic shear-slip failure along the structural surface. When the rock mass containing structural planes undergoes strain-type splitting failure，tension cracks or fractures approximately parallel to the free surface occur on both sides of the structural plane，leading to the occurrence of violent rockbursts. The boundary of the rockburst pit is enclosed by the structural plane and the split fracture，and the maximum acceleration of the rockburst ejection can reach 13.56 g. In contrast，when the rock mass with structural planes is subjected to shear-slip failure，the failure energy of the rock mass is greatly weakened，and almost no dynamic failure phenomenon occurs. These research results present significant implications for disaster prevention，control，and mitigation strategies in deep buried underground engineering.

Hydrodynamically induced colluvial landslide is one of the main geological disasters in southwest China. It is significant to investigate the erosion differentiation mechanism of soil-rock mixtures for revealing the landslide mechanism in depth. The rock content is the most important factor affecting the erosion differentiation characteristics of soil-rock mixtures. Based on the seepage erosion tests of soil-rock mixtures with different rock content，the erosion differentiation characteristics and mechanism of soil-rock mixtures are revealed. The results show that there are four random states in the process of seepage erosion of soil-rock mixtures：erosion intensification，erosion mitigation，internal block structure reorganization and erosion stability. The rock content has a significant effect on the erosion differentiation characteristics. The permeability coefficient of soil-rock mixture increases at first，then decreases subsequently，and then increases again with the increasing rock content，and the lowest value is observed at the rock content of 60%，which was less than 1×10－2 cm/s and cause a slight fluctuation. Whereas，the permeability coefficient of soil-stone mixtures at a high rock content is nearly unchanged before and after seepage，with a change rate less than 10%. The amount of erosion increases with the increasing hydraulic gradient. On the basis of change of erosion amount，the seepage erosion is divided into three stages：violent erosion，slow erosion and stable seepage stage. The critical hydraulic gradient decreases with increasing rock content. The rock content affects the permeability of the soil-rock mixtures by affecting the filling form of the soil-rock structure，and the full-filled structure has the best impermeability，which provides ideas and references for revealing the mechanism of hydraulic instability of the colluvial slope.

High and steep anti-dip rock slopes are widely distributed in southwest China and rock layers in these slopes are easy to fracture at great depths，resulting in large scale landslides. Earthquakes are important external factors，inducing the toppling failure of anti-dip rock slopes. To analyze the stability of anti-dip rock slopes under seismic loads，adjacent rock layers are taken as the basic mechanical analysis unit，and regarded as cantilever beams with free or coordinated deformation. The discrimination conditions for two deformation modes are proposed. On this basis，a mechanical model for the flexural toppling failure of anti-dip rock slopes under seismic loads was proposed，and mechanical equilibrium equations for rock layers in the free or coordinated deformation zones were established. The calculation method for dividing rock layer deformation modes and the overall stability judgment method of the slope were provided. Based on MATLAB，the programming of flexural toppling analysis of anti-dip rock slopes under seismic loads was achieved. By comparing the UDEC numerical results of slopes under different earthquake impact coefficients，it was found that the maximum difference in slope safety factor between theoretical calculation and numerical simulation does not exceed 16%，and the range of free deformation zone and coordinated deformation zone is basically consistent，which verifies the correctness of the method proposed in this article. Parameter analysis found that the inclination angle of rock layers has a significant impact on seismic action，Under the same seismic impact coefficient，the reduction amplitude of the slope safety coefficient increases with the increase of inclination angle of rock layers. while the slope angle and rock layer thickness have a relatively small impact on seismic action. The study is helpful to prevent and control the failure of such rock slopes in seismic high-risk areas.

Based on the existing theories and experimental conclusions on the spatial damage surface characteristics of the principal stresses of rock materials，and in response to the problem that the conventional strength criterion has many parameters and the physical significance is not clear， it is put forward that there exists a strength curve in the bi-directional isotropic tensile stress point with the point of view that d(?1－?3)/d?m = 3， by analyzing the characteristics of the change of the conventional triaxial compressive strength curves in the bi-directional isotropic tensile stress point(0，?tt，?tt). Meanwhile，a hyperbolic-type strength criterion containing two parameters of two-way isotropic tensile strength ?tt and three-way isotropic tensile strength ?ttt is established，which takes into account both the average stress effect on the strength curves on the meridian and the π-plane，and the parameters have clear physical meanings. In order to verify its reasonableness and applicability，the strength criterion was utilized to fit and calculate the triaxial test data of 14 types of rocks in the published literature，and compared and analyzed with Burzynski?s parabolic criterion and You Mingqing?s exponential criterion，which have higher fitting accuracy. The results show that the fitting effect of this criterion is better for both conventional triaxial test data and true triaxial test data，with the correlation coefficients above 0.99，and the sizes of the fitted bidirectional isotropic tensile strengths ?tt and the three-directional isotropic tensile strengths ?ttt are in a reasonable range；at the same time，the fitting results under different constraints corroborate the idea that there exists d(?1－?3)/d?m = 3 at the bidirectional equal tensile stress points(0，?tt，?tt). It shows that the criterion is reasonable and applicable，and can provide some practical guidance value for the field of rock engineering.

The stratification and bedding characteristics of the coal-bearing construction make the surrounding rock more occur a shear disaster. To further investigate the shear fracture behaviour of coal rock masses under cyclic loading conditions，uniaxial compression tests on sandy mudstone were carried out using constant amplitude cyclic and stepwise linear cyclic loading and unloading methods in conjunction with CT scanning. The “Domino” structure of shear rupture of rock samples and its evolutionary characteristics were analysed by means of the rupture morphology and the stress-strain curve of the whole process. The results show that，under uniaxial compression and constant amplitude cycles and stepwise linear cycles，shear failure occurs in all rock samples. Moreover，the shear fracture zone formed by the failure of rock samples under stepwise linear loading and unloading cycles includes several strain localization zones with a “Domino” structure，and the stress-strain curve corresponding to the failure process shows a special “hysteresis-reciprocation-hysteresis-reciprocation” oscillation fluctuation. The strain localization zone presents the evolution process of nucleation，initiation crack，expansion，decay and conduction. The rotating-gyration motion of the fragmented block with the “Domino” structure causes multi-stage dissipation of the input energy and elastic storage energy after the peak in the friction of the block，which prolongs the damage time and has a significant “slow release” effect. The shear crack morphological evolution and stress–strain concealment information cooperate with each other to divide the shear failure process into six failure stages，namely：crack initiation micropropagation(I)，crack initial propagation(II)，primary shear crack propagation(III)，Crack propagation metastable(IV)，rapid crack propagation(V)，accelerated failure(VI). The “Domino” structure is a unique form of shear failure，and the energy “slow release” effect it plays may be a new idea for coal mine roadways to use the surrounding rock structure to relieve pressure and protect the roadway.

Within deep coal-bearing strata，a prolonged diagenesis process leads to the existence of a lithological transition zone between some coal and rock layers. This transition zone，together with the adjacent rock and coal layers，constitutes a composite structure. To study the influence of the transition layer's height on the deterioration characteristics of the coal-rock composite，a proportionate design of coal，rock，and transition layer artificial materials，as well as a production plan for coal-transition layer-rock(CFR) composite specimens，were initially proposed. On this basis，uniaxial compression tests of artificial CFR composite specimens with varying transition layer heights were conducted. In addition，based on the discrete element numerical simulation software PFC，rigid clusters and spherical particles were used to represent coal and rock particles in the transition layer. Through their proportion changes，a PFC characterization model for the transition layer and CFR composite structure was constructed. Combined with the test results，the model parameters were calibrated，and the algorithm?s effectiveness was validated. Both experimental and numerical simulation results indicate that as the height of the transition layer increases，specimen strength，pre-peak dissipated energy，and acoustic emission b initially decrease then increase，while the elastic strain energy shows a progressively increasing trend. The distribution range of numerical simulation micro-fracture angles also initially narrows then expands with increasing height，and the micro-crack initiation area gradually shifts from the coal layer to the transition layer，with the acoustic emission location progressively concentrating on the interface between the coal and transition layer. These results demonstrate that the presence of the transition layer significantly alters the physical and mechanical properties of the coal-rock composite structure.

In order to address the issue of effectively identifying abnormal data in real-time monitoring of landslide cracks，occasional abnormal thresholds based on the various deformation stages of landslides are established. Additionally，a real-time anomaly detection method for time series data，utilizing interval prediction，is proposed. This method takes into consideration the temporal logic relationship between data and the correlated information of landslide deformation stages. Firstly，the time series characteristics of cumulative displacement of crack gauge are extracted using the autoregressive integrated moving average(ARIMA) model. Subsequently，an interval prediction model is constructed，and the sliding window algorithm is employed to predict sub-sequences. Secondly，to determine prospective abnormal points，a modified confidence interval(with ? = 0.05) is utilized，and occasional abnormal thresholds are established for different deformation stages of landslides. Finally，exceptional information is obtained through combined anomaly recognition. The research results indicate that this method accurately identifies abnormal data values and demonstrates universal applicability in real-time anomaly detection of time series data. By comparing the predicted interval of the model with the abnormal values，the real-time possibility of data abnormalities can be obtained. Furthermore，this method provides valuable data reference for intelligent decision-making in landslide monitoring and early warning.

The large-scale collapse of goaf is one of the typical disasters in underground mines. This disaster is primarily triggered by the instability of the critical key pillar within the goaf. In this paper，to accurately identify the critical pillar in the goaf，the fundamental concept of the critical pillar in goaf is developed based on the cascading failure mechanism of pillar group in goaf and the principles of risk theory. Additionally，a novel method for recognizing the critical pillar is proposed based on a comprehensive risk analysis of pillar instability. The methodology involves several key steps：(1) obtaining the distribution characteristics of pillar strength through field research or empirical estimations，and then establishing the probability density function for pillar strength within the goaf；(2) computing the stress on each pillar by introducing the formula of maximum stress diffusion distance，subsequently，calculating the instability probability for each pillar；(3) utilizing a dynamic updating iterative approach to assess the stress transfer and instability patterns within the pillar group system，considering any pillar as the initial failure point；(4) quantitatively characterizing the consequence of any single pillar instability by using the index of the bearing area loss rate of the pillar group within the goaf，specifically measuring the severity of goaf collapse disasters induced by individual pillar instability；(5) determining the instability risk value for each pillar by calculating the product of the instability probability and its associated consequence. Accordingly，identifying the critical pillar within the goaf as the one with the highest instability risk value. The proposed method is applied to Fetr6 mining area for verification. The results demonstrate that this method is easy to implement，involving straightforward parameter acquisition and calculation processes，while also offering clear physical significance. Furthermore，it proves to be more scientifically and logically sound than the traditional safety factor method. Thus，this method holds promise for wide-ranging applications in practical engineering scenarios.

Geological structure significantly influences the evolution of suffusion in alluvium foundations，and then may affects the safety of dams. However，the present studies mainly focus on the internal instability and hydraulic conditions initiating suffusion of the internally unstable soils，and the influence of geological structure is neglected. A series of transparent suffusion tests on double-layered foundation were carried out by a new suffusion visualization apparatus based on planar laser induced fluorescence technology. In the double-layered foundation，the upper and lower soil layers serve as filter and base soil，respectively. The influence of retention ratio of double-layered soil on the evolution of suffusion was investigated. The results indicate that the upper soil layer has a remarkable influence on the critical hydraulic gradients at the initiation of suffusion and at blowout. The critical hydraulic gradients decrease with the increase of the retention ratio. The retention ratio significantly influences the fine particle migration and failure modes. If the retention ratio is less than or equal to 5，the eroded fine particles from the lower soil layer were clogged at the interface，and eventually induces tensile failure；if the retention ratio is larger than 5，the upper soil layer can?t effectively protect the lower soil layer，the fine particles from the lower soil layer were eroded into the upper soil layer，and then pass through the layer，and eventually induce suffusion failure. A new filter criterion for the internally unstable base soils was proposed，and then it was validated by the experimental results presented in reference.

The researches on the thermo-mechanical response of energy piles primarily focus on vertical loads，with limited studies considering the influence of horizontal loads. To investigate the thermo-mechanical response characteristics of energy piles subjected to horizontal loads，a model-scale test was conducted to analyze the variations in pile top displacement，pile bending moment，pore water pressure and soil pressure in front of the pile in saturated clay under different temperature gradients. The research results showed that both heating and cooling of the pile induced additional pile top displacement. Cooling caused a greater additional displacement，reaching 0.22%D (D is the diameter of the pile)，while heating induced an additional displacement of 0.13%D. The ultimate bearing capacity of the pile increased after heating/cooling compared to the test pile. The increase was more observed after heating，approximately 32.7%，whereas it was about 26.1% after cooling. This was due to the thermal consolidation effect during heating significantly enhanced the strength of the soil. Heating and cooling did not have a significant impact on the location of the maximum bending moment，as the maximum bending moment consistently occurred at a depth of 37.5%L(L is the burial length of the pile) before and after heating/cooling. The maximum bending moment increased after heating/cooling. During cooling，the maximum bending moment initially increased and then stabilized gradually. During heating，the maximum bending moment initially decreased and then gradually increased，exceeding the bending moment before heating. During this period，the pile top displacement continued to increase，suggesting the possibility of rigid rotation of the pile in the initial stage of heating. Heating and cooling had different effects on the soil pressure in front of the pile. Overall，the upper part of the soil pressure generally increased，while the lower part decreased. Heating and cooling caused variations in pore water pressure in the soil with changing temperatures，resulting in positive or negative excess pore water pressure.