Compressed air energy storage(CAES) is a kind of large-scale energy storage technology that is expected to be commercialized. As an underground gas storage engineering structure，the newly-excavated hard rock cavern has attracted much attentions due to its wide adaptability and practicability. Compared with traditional underground engineering，underground rock caverns for compressed air storage face many new challenges due to the periodic high internal pressure and temperature during the course of operation. Recently，great advances about the construction and operation of compressed air energy storage in hard rock caverns have been made by researchers around the world. It is thus imperative to systematically review the progress in this direction，which can help engineers to better understand the development of such emerging energy storage technology in practice. Firstly，the basic principles and scientific problems of compressed air energy storage are described. Secondly，the research progress related to construction and operation is summarized，including airtight performance of sealing structure，thermal transition process of surrounding rock-lining-sealing layer-air during the process of inflation and deflation，uplift failure of the rock mass，and plug stability. Besides，several key scientific and technological issues which need to be further studied are discussed.

The long-term durability of the tunnel lining following crack grouting serves as a major guiding principle in the choice and enhancement of crack treatment techniques. According to the field investigation，a 420-day crack grouting and secondary corrosion test of concrete with non-through cracks was carried out，along with uniaxial compression and acoustic emission tests，in order to examine the impact of non-through crack grouting on the compressive characteristics of tunnel lining concrete under the secondary sulfate corrosion of free surface evaporation. The test findings demonstrate that the compressive failure features of concrete corroded by sulfate change from diagonal conical failure to full spalling on one side of the attacked surface. In addition，non-through deep cracks accelerate the strength loss of concrete in a sulfate environment. During the uniaxial compression，the acoustic emission stages I–IV show good agreement with the stress-strain curve in the following stages：the compression stage，elastic stage，yield stage，and post peak-stage. Furthermore，with increasing the corrosion time，the compression yield point of the specimen advances，the proportion of stage Ⅱ decreases，and the proportion of stage Ⅲ increases. Non-through crack grouting increases the concrete?s immediate strength and decreases its strength loss during secondary corrosion. However，non-through crack grouting had no effect on the concrete?s damage or acoustic emission characteristics during the compression process，and the grouting effect diminishes as the grouting time increases.

Understanding the mesostructural evolution of high-temperature damaged granite is crucial to reveal the degradation mechanism of its macro-physical and mechanical properties. In this study，granite was treated at high temperature(25 ℃，100 ℃，200 ℃，300 ℃，400 ℃，500 ℃ and 600 ℃)，and then the uniaxial compression test was carried out on the thermal-treated granite. Finally，the meso-structure of granite was qualitatively and quantitatively analyzed using optical microscope，CT scanning and nuclear magnetic resonance(NMR). The results indicate that the mechanical properties of granite are strongly dependent on temperature，and the compressive strength increases at first and then decreases with the temperature. 200 ℃ is the peak temperature of thermal strengthening effect，400 ℃ is the threshold temperature for meso structural damage of granite，and 600 ℃ is the threshold temperature of brittle-ductile transition of granite. Further analysis indicates that the high temperature leads to a denser structure of granite and the porosity decreases with temperature at 25 ℃–200 ℃. The initiation and propagation of thermally-induced cracks can be observed in granite after 300 ℃. These cracks propagate from the edge to the interior of the specimen，and the number of pores increases with the temperature，and mesopore and macropores are dominant. The porosity increases exponentially with temperature. In addition，the fractal dimension of micropores decreases with temperature，which means that high temperature simplifies the structure of micropores，while mesopores and macropores show good fractal characteristics and are not affected by temperature.

The continuous excavation of engineering projects leads to dynamic unloading and damage effects on the surrounding rock，and the mechanical and hydraulic properties of the unloaded and damaged rock mass jointly affect the stability and safety of the project. In view of this，this paper analyzes the deformation characteristics of medium-to-fine-grained quartz sandstone under dynamic pre-peak unloading and wetting-swelling cycles from both macro and micro perspectives. The results indicate that the peak strength of the unloaded and damaged samples is significantly reduced，and the degree of sample failure intensifies. Under the cyclic action of dynamic unloading and wetting-swelling cycles，the cumulative damage of the samples generally shows an upward trend. The more cyclic action of unloading and wetting-swelling，the greater the increment in porosity and the more water absorbed due to swelling. The micro-damage index exhibits an exponential growth pattern with the cycle number. As the destruction approaches，the proportion of medium- and large-sized pores in the samples increases. The greater the unloading amount，the less action required for the destruction of the sample，with an unloading amount of 50% defined as the threshold for controlling the destruction rate under unloading and wetting-swelling cycles. When the unloading amount exceeds 50%，the destruction process accelerates. By incorporating unloading damage and wetting-drying cycle times into the Hooke element to modify the Kelvin model，the swelling creep characteristics of the samples under dynamic excavation unloading conditions can be better simulated.

To explore the precursor of rock instability，rockburst tests were conducted on granite using acoustic emission(AE) monitoring system. The failure mode and strength characteristics of granite rockburst were obtained. Based on acoustic emission parameters and multi fractal dimension calculation，the temporal fractal characteristics and crack evolution characteristics of granite during rockburst process were quantitatively analyzed. The results show that granite experiences violent blasting destruction under true triaxial loading and unloading conditions. The rupture strength is 0.76–1.04 times of its uniaxial compressive strength. Before the rockburst，the AE ringing counts have an intensive and explosive growth while the AE b-value shows a sudden continuous decline；Based on AE cluster analysis of RA-AF distribution division，it is found that the proportion of shear type cracks increases at first and then becomes stable or has a little decrease until finally increases significantly. The multifractal spectral width of AE exhibits a sudden decrease at the moment of rockburst occurrence. Hence，the second sudden increase in the proportion of shear type cracks and the sudden descent turning point of can be served as precursors of rock instability. Compared the warning information of rockburst determined by AE ringing count，b-value，RA-AF distribution and multifractal dimension，the average precursor response coefficients are 0.72%，2.18%，5.40% and 3.97%，respectively. Since the evolution of internal cracks and time sequence property of damage in rock are taken into account，the response time for identifying precursor based on the proportion of shear cracks and multifractal dimension is earlier. They can more finely characterize the complexity of AE signals and reveal the mechanism of rock fracture evolution. The research results can provide reference for revealing the mechanism of rockburst occurrence and establishing disaster warning methods.

To investigate the mechanical behavior of the underground reservoir?s floor in a coal mine subjected to combined dry-saturated cycling and disturbances of mining-induced stress，triaxial cyclic loading-unloading tests of sandstone under dry and saturated conditions are conducted using the MTS815 testing system，to analyze the damage evolution characteristics and the critical jumping behavior from linear to non-linear transition of dilatancy at pre- and post-failure. By introducing a damage variable dependent on the plastic volumetric strain，a critical index-based percolation model is established to describe the nonlinear dilatancy phenomenon. The experimental results show that the brittle behavior of sandstone is weakened by water saturation and a competitive relationship between the water-weakening effect and the hydraulic pressure-strengthening effect is observed. In addition，the maximum dilation angle is suggested as a criterion to divide the dilating deformation into the fracture growth and the shear-induced slippage. The damage variable?s evolution of sandstone under dry states also presents a critical jumping phenomenon at the transition boundary between two stages，while under saturation conditions it shows a gradual transition. In the fracture growth stage，the proposed percolation model fits the testing data well，which confirms the validity of proposed percolation model. Moreover，another percolation model to describe the volumetric strain evolution considering the damage variables was also derived.

In order to obtain the effects of temperature and bedding plane on the microstructure，macroscopic mechanical parameters and fracture characteristics during the in-situ pyrolysis of oil shale，the self-developed real-time high-temperature thermo-mechanical coupling CT scanning device and high-temperature rock mechanics test system were used to carry out thermo-mechanical coupling CT scanning and uniaxial compression tests on oil shale in two directions of perpendicular to bedding and parallel to bedding from 20 ℃ to 600 ℃. The results reveal that：(1) Up to 400 ℃，the stress state of oil shale is the key factor to determine the law of pore fracture propagation. Under perpendicular loading to the bedding，the pore diameter and fracture aperture initially decreasing and then increasing with temperature increasing. Under parallel loading to the bedding，primary fractures propagate along the bedding planes，accompanied by the emergence of new fractures. (2) When loading in both perpendicular to and parallel bedding directions，the compressive strength，elastic modulus，and Poisson's ratio of oil shale initially decreasing and then increasing. Specifically，the compressive strength and elastic modulus reach their minimum values at 400 ℃，whereas the Poisson?s ratio attains its minimum at 500 ℃ and 200 ℃ when loading perpendicular to bedding and parallel to bedding，respectively. (3) Except for the the fracture damage stress during perpendicular bedding loading initially increases，then decreases，and subsequently increases with temperature，the initial stress during perpendicular bedding loading ，parallel bedding loading ，and damage stress decrease initially and then increase，reaching their minimum values at 400 ℃. These research findings provide essential data for reservoir reconstruction and cementing technology in the in-situ mining process of oil shale.

Investigating the fracture characteristics of rocks subjected to variable crack propagation rates is essential for analyzing and forecasting the stability and safety profiles of engineering infrastructures. To study the fracture behavior of Beishan granite under different main crack propagation rates，five different loading rates were set to achieve different crack propagation rates. During the test，digital image correlation(DIC) technology and three dimensional laser scanning technology were used to obtain the deformation information and fracture surface morphology of the specimen during loading. Based on the change history of the specimen strain field，a new method for calculating the instantaneous propagation rate of the failed main crack was proposed. The result show that the loading rate/average crack propagation rate significantly affected the propagation process of the main crack. Capturing the mutation point of the strain field change history can effectively estimate the instantaneous propagation rate of the failed main crack at different times. Within the range of low and medium loading rates，the instantaneous propagation rate of the main crack showed a significant rapid growth stage and stable propagation stage. However，within the range of high loading rates，the instantaneous propagation rate of the main crack increased linearly，which directly led to an earlier initiation load stage of the fracture process zone(FPZ) and a reduction in the roughness of the fracture surface. In addition，it was found that the average propagation rate of the failed main crack was positively correlated with the fracture toughness and peak FPZ length，and negatively correlated with the fractal dimension of the fracture surface.

The deterioration，fragmentation and dilation effects in high-stress soft rock tunnel surrounding rock are significant，making large deformation disasters in soft rock，a critical issue in the construction of long and deep tunnels. To clarify the process and mechanism of large deformation disasters in soft rock tunnels under high-stress conditions，a microseismic monitoring system(MS) was established in a soft rock tunnel. The deformation and failure processes of the surrounding rock under different support strengths were analyzed. Combining convergence monitoring and numerical simulation，the study examined the evolution of cracks and large deformation characteristics of the surrounding rock，revealing the mechanisms of internal fracturing and damage zone evolution under high-stress and strong unloading conditions. The results show that tunnel convergence in high-stress soft rock is closely related to geological conditions and support conditions. Due to nearly vertical joint development in the surrounding rock，deformation at the sidewalls of the tunnel exceeds that at the crown and floor under strong unloading. Different support forms exhibit distinct characteristics in tunnel convergence and MS parameters. Strong support reduces tunnel convergence，decreases daily MS frequency，reduces cumulative apparent volume，and lowers MS event energy and cumulative released energy. Numerical simulation studied the deformation and failure characteristics of the surrounding rock，and a comparative analysis between numerical simulation results and field tests indicated that the damage zone of the tunnel surrounding rock is approximately 8 meters. The study demonstrates that MS monitoring can reflect the large deformation and failure process of soft rock tunnels，providing a scientific basis for the design of support measures and timing in tunnel construction.

The fault dislocation effect on the tunnel is of significance when a spiral tunnel crosses active fault zones in the western regions of China. In order to clarify the dislocation response of fault-crossing spiral tunnels subjected to the normal faulting，three groups of model tests with different radius of curvature with the longitudinal slope of 3% were performed experimentally，where the critical design parameters of spiral tunnels and the relative stiffness ratio of soil-structure were considered. And then，a rubber-steel flexible joint with certain flexural bearing capacity was utilized on spiral tunnel to explore the anti-dislocation response of tunnel. The performances of tunnel with or without flexible joint measures were subsequently compared and analyzed. The results show that the tunnel near the fault plane and the interface of fault zone and hanging wall are affected by the normal faulting and the tunnel invert is more adverse. The incremental strain at the haunch of the spiral tunnel with the increase of fault dislocation is related to the radius of curvature. The circumferential strain at the haunch with a small radius of curvature and the longitudinal strain at the tunnel crown and invert are more sensitive to the fault dislocation. Affected by the rubber-steel flexible joints with certain bearing capacity，the segmental design of spiral tunnel plays a good adaptability to fault dislocation，especially for the stress reduction on the tunnel invert. The research results can provide a design reference for the fault-crossing spiral tunnels to adapt the fault dislocation in western mountainous areas of China.

Backfilling mining is an effective method to reduce the mining pressure，rock movement and surface subsidence. To guide the selection of support parameters for the backfilling longwall face，taking the 1123 longwall panel of Gucheng coal mine as the background，theoretical analysis，physical simulation and on-site measurement are used to study the characteristics of rock movement under the conditions of backfilling mining with thick top coal and hard roof，to reveal the coupling relationship between the support and the surrounding rock，and to propose the optimization method of support parameters for backfilling face with thick top coal. The results show that the maximum height of mining-induced fractures under the support of backfilling body is located at the lower edge of the hard roof. The number of microseismic events in the roof is less than that in the floor，and the maximum height is 30 m. The roof load time series curve is dominated by the descending resistance type，and there is no periodic variation characteristics，indicating that the hard roof is characterised by continuous settlement. The settlement model of the hard roof is constructed and the settlement curve of“?”shape is obtained. The backfilling rate of the gob reaches 90%，and the movement mode of the hard roof changes from periodic fracture to continuous settlement type. Through uniaxial and triaxial compression experiments，combined with CT scans，it is found that after thick top coals loss restriction of the gob side，the internal fractures expand severely and the crushing coefficient increases，which reduces the backfilling ratio. A method for determining the support resistance in backfilling face is proposed. The interaction relationship between support and surrounding rock is analyzed from two aspects of stiffness coupling and strength coupling. Considering the stiffness and strength of thick top coal，the identification of support parameter optimization area is realized，and the optimization principle of support parameters of backfilling face is proposed. The resistance surface is divided into high sensitive area and low sensitive area，and it is proposed that the stiffness should be selected in the high sensitive area. The lower limit of the initial support force is the immediate roof and thick top coal load，and the upper limit value is the residual strength of thick top coal. The site industrial test of support parameters optimization of 1123 panel is carried out. It is found that the initial support force of 24 MPa exceeds the upper limit of support strength，which directly leads to the secondary breakage of thick top coal and the resistance reduction of support load time series curve. When the initial support force is reduced to 10 MPa，the load time series curve is transformed into a increase of resistance throughout the whole process，and the thick top coal in the roof control area is continuously settled. The secondary crushing and roof fall phenomenon are reduced，which significantly improves the backfilling mining efficiency.

To investigate the physical processes and mechanical responses of deep-seated tectonic fragmentation zones in metal mines induced by alternative fatigue-creep loads，hollow cylindrical granite specimens with varying inclinations of weak interlayers were prepared，and the impact of weak interlayer inclinations on the time-dependent instability of the composite structure specimens was investigated by employing a combination of macroscopic mechanical tests and microscopic CT scanning. The findings indicate that：(1) The resistance of composite structure specimens to alternative fatigue-creep loads is significantly influenced by the inclination of weak interlayers. As the inclination of weak interlayers increases from 5° to 35°，the confining pressure unloading at the point of failure gradually decreases，with values of 11.58，7.49，7.22 and 5.07 MPa，respectively. (2) When subjected to the loading path of alternative fatigue and creep，the composite structure specimens exhibit nonlinear，exponential relationships in their axial，radial，and volumetric strains，as well as in dissipated strain energy，with the loading stages. However，during the final loading stage，the composite structure specimens display unique deformation and energy evolution characteristics. (3) The energy dissipation of the composite structure is characterized by the initiation，propagation，and connection of internal cracks in the rock matrix，alongside the shear slip deformation of the weak interlayers. The incompatible deformation between the weak interlayers and the rock matrix leads to volume expansion and rock matrix fracturing. Notably，with the increase in interlayer inclinations，the energy dissipation of the composite structure shows a decreasing- then-increasing trend. (4) CT scanning test results indicate that the connection of failure surfaces between the weak interlayers and cavities is the fundamental cause of failure in the composite structure. The final plastic deformation of the weak interlayers shows a positive correlation with the interlayer inclinations. These research findings have significant theoretical implications for revealing the temporal disturbance mechanism of large deformations in the surrounding rocks of deep-seated tectonic fragmentation zones in mining engineering.

The locked section is the key controlling factor of“three-stage”rockslides. In order to study the damage characteristics of the locked section of slopes in cold regions，a double-sided freeze-thaw test was carried out on the slope model，and the change of temperature field and the influence of frost heave force on the deformation during the water-ice phase transition were analyzed. Based on rock mechanics，a frost heave model considering the effect of ice wedge extrusion is established，and the mechanism of frost thaw weathering of crack slopes is investigated. The slope shoulder is frozen first，and the frozen peak advances from the shoulder into the rock mass. The fracture failure of the“three-stage”rock slope is dominated by frost heave of the tension fissure at the back edge. The frost heave force is the largest and the deformation of the locked section is the largest when the top of the rear edge tension crack drops from －3.5 ℃ to －6 ℃(the bottom of the crack drops from 0 ℃ to －2.6 ℃) and the cracking failure of the locked section also occurs at this stage. The frost heave force is positively correlated with the length of tensile fracture at the back edge，and there is no shear trace on the tensile fracture surface. By simulating the frost heave process of the tension crack at the back edge of the“three-stage”rock slope，the distribution characteristics of the displacement field and stress field of the slope and the crack propagation path of the locked section are analyzed，and the correlation between the Angle of the locked section and the frost heave cracking and the disaster mechanism of the tension crack at the back edge is revealed. The research results can provide technical reference for slope construction in cold regions.

In order to study the influence of deep complex stiffness environment difference on rock mass mechanical behavior，the two-dimensional variable stiffness dynamic failure simulation test system，combined with acoustic emission(AE) monitoring equipment，was used to carry out experimental research on unilateral and biaxial compression of sandstone in different stiffness environments，aiming to discuss the effects of loading system stiffness on the mechanical response characteristics，post-peak rebound deformation characteristics and energy evolution of sandstone under unilateral and biaxial constraints. The results show that：(1) The stress-strain curve of sandstone specimens is significantly affected by the stiffness environment in the post-peak stage. Under the uniaxial conditions，with the decrease of the stiffness of the loading system，the stress drop is faster and more macroscopic cracks are generated. Under the lateral constraints，the stiffness of the loading system has multiple rebound impacts on the rock samples，affecting the fluctuation of the post-peak curve and the fluctuation of acoustic emission(AE) events. It shows a step increase in energy. (2) The stiffness of the loading system is negatively correlated with the stored strain energy of the testing machine frame，the extreme post-peak rebound velocity and the cumulative maximum dissipated energy under unidirectional and bidirectional loading. Lower loading stiffness leads to greater energy release velocity and increases the macroscopic crack and damage degree of the rock sample. (3) Under the control of the stiffness of the loading system，the stored strain energy，post-peak instantaneous rebound velocity and cumulative dissipated energy of the testing machine frame are positively correlated with the lateral binding force，and the lateral constraint conditions enhance the stiffness effect and have a significant impact on the deformation characteristics of rock samples. (4) The low-stiffness environment will produce dynamic impact and energy supply to the rock mass，resulting in dynamic damage and binding force，which can improve the energy storage limit of the rock mass and weaken the damage degree of the rock mass in the rigidity environment.

Calcareous sand is one of the important materials for island construction. There are few reports about the change of shear strength of calcareous sand after cyclic shear. In this paper，the shear strength of calcareous sand and quartz sand was obtained through consolidated drained and undrained triaxial shear tests. Based on the shear strength under static load，undrained cyclic traxial tests under different static stress ratios and cyclic stress ratios，as well as undrained triaxial shear tests after cyclic loading，were conducted. The results show that the static stress ratio mainly affects the upper limit of pore pressure development，while the cyclic stress ratio not only affects the upper limit of pore pressure development，but also affects the strain value at the end of the cycle，which is more obvious in calcareous sand. The development of pore pressure is negatively correlated with the static stress ratio and positively correlated with the cyclic stress ratio. The cumulative pore pressure of calcareous sand is greater than that of quartz sand under the same cyclic loading，making it more prone to liquefaction under high cyclic stress ratios. After undrained cyclic traxial tests with different static stress ratios and cyclic stress ratios，the peak deviatoric stress of sand decreases. It is worth noting that compared with the end of undrained cyclic traxial tests，the increase of static stress ratio is beneficial to the improvement of shear strength of calcareous sand after cyclic loading to a certain extent，while the increase of cyclic stress ratio is beneficial to the improvement of shear strength of quartz sand after cyclic loading to a certain extent.

Using CE–5(Chang?e–5) simulated lunar soil as the main material，three types of experimental samples(YR–1，YR–2，YR–3) were made by adding inorganic curing agents. A universal servo hydraulic press (100 kN) was used to apply vertical loads，and stress-strain curves were obtained. The internal morphology and micro cavity characteristics of the samples were observed using scanning electron microscopy. The failure morphology，deformation performance，and elastic modulus of the solidified lunar soil samples were studied. The uniaxial compressive constitutive model of CE–5 simulated lunar soil solid samples was obtained through segmented analysis. The conclusion is as follows：(1) The compressive strength is related to the water cement ratio and the amount of cementitious materials used. As the water cement ratio decreases，the compressive strength increases，and as the amount of curing agent increases. (2) There are generally many micro voids and small cracks inside the solidified sample. When the external pressure reaches the ultimate strength，the micro voids and micro cracks expand and penetrate，leading to the failure of the sample. (3) The experimental results of stress-strain curves were fitted using cubic polynomials and rational fractions to obtain the rising and falling sections of the stress-strain curves of lunar solidified soil. A segmented constitutive model for lunar solidified soil specimens was proposed，and the calculated results of the model were in good agreement with the experimental curves，providing a theoretical basis for the technical analysis of lunar soil engineering.

To investigate the distribution characteristics of active earth pressure on non-smooth retaining walls and the stress state of soil behind the wall under active limit equilibrium conditions，a method for calculating the active earth pressure of retaining walls under ultimate stress conditions is developed for cohesionless soil. Firstly，it is assumed that in the limiting equilibrium of the sliding wedge，the soil elements on the slip surface，at the wall-soil interface，and within the wedge body all achieve the ultimate stress state. Additionally，the principal stresses within the wedge are assumed to transfer as a circular arc principal stress trace. The sliding soil wedge is then discretized into multiple thin-layer units along the minor principal stress traces. By applying static equilibrium principles，the active earth pressure on retaining walls under ultimate stress conditions is derived through force analysis of these units. Subsequently，the influence of the wall-soil friction angle   on the distribution form，magnitude，resultant force action point of active earth pressure，and overturning moment at the base of the retaining wall is analyzed，and comparisons are made with Coulomb?s theory and other earth pressure theories. Theoretical analysis demonstrates that：(1) The active earth pressure   exhibits a convex nonlinear distribution with depth，which is significantly influenced by the roughness of the retaining wall's back，characterized by the wall-soil friction angle  . When the wall back is smooth( = 0°)，the earth pressure distribution degenerates into Coulomb?s linear distribution. As the wall-soil friction angle increases，the earth pressure distribution curve shifts gradually to the left，with the inflection point on the curve rising，accentuating the nonlinear effect. (2) As the wall-soil friction angle increases，the resultant force of the active earth pressure gradually decreases，while the position of the resultant force?s action point rises due to the influence of nonlinear distribution. The overturning moment at the base of the wall initially decreases and then increases. (3) The resultant force of active earth pressure under ultimate stress conditions is the outer envelope of the Coulomb’s earth pressure resultant force. Based on Mohr-Coulomb strength theory，it is deduced that the stress state of internal units within the sliding soil wedge at limit equilibrium can be described as follows：When the retaining wall back is smooth( = 0°)，internal units of the sliding soil wedge reach ultimate stress conditions，corresponding to the classical Rankine earth pressure theory. When the retaining wall back is rough( ＞0°)，internal units of the sliding soil wedge enter a plastic-failure stress state. As the roughness of the retaining wall back increases，the plasticity becomes more pronounced. (4) The active earth pressure under ultimate stress conditions represents the upper bound plastic solution，while Coulomb?s earth pressure represents the lower bound plastic solution. Finally，the feasibility and rationality of the proposed method are validated through numerical simulations and practical examples.

Loess is susceptible to significant changes in strength and volumetric strain under loading or wetting. In this study，to address the soil response induced by wide variations of saturation under hydro-mechanical action，an elastoplastic model considering the entire possible range of suction and stresses is developed by focusing on the case of multi-phase coupling in unsaturated loess，using the generalized effective stress and modified suction as the stress variables. This model unifies the situation of gas phase closure caused by high saturation into the generalized effective stress framework，introduces the damage parameter for the influence of closed gas on soil，and uniformly describes the deformation and strength of unsaturated loess under wide variations of saturation. The reasonableness and reliability of the model have been verified through the corresponding stress and hydraulic path tests. The results show that the proposed model can better reflect the loading effect of unsaturated loess influenced by the closed gas. It adeptly reflects not only the coupled hardening of the solid-liquid phase but also accurately portrays the influence of closed gas on deformation and strength under different hydro-mechanical actions.