The support design of large underground caverns is a complicated non-linear issue that is related to geology，rock mechanics，cavern geometry，excavation method，etc. In order to solve the shortcomings of the empirical support design system，such as Q，RMR，design code，etc.，which are lack of consideration for the influence of the strength of the rock mass，the geo-stress and the cavern geometry characteristics，a new comprehensive index D is proposed，which is including，rock mass quality，peak strength and residual strength of the rock mass，geo-stress，cavern geometry，and the excavation method. The scoring table for each factor is proposed. A new function for evaluating support pressure and determining the thickness of rock pillars for adjacent cavern complexes，is created based on D and the span of caverns. Detail recommendations for support design include various combinations of shotcrete，rock bolts，prestressed anchor cables，steel ribs and concrete lining，and the suggestion for the spacing and length of rock bolts or prestressed anchor cables，the requisite thickness of the shotcrete，and the locked force of prestress anchor cables is also proposed. This new design system is verified using more than 45 large underground caverns of different hydroelectric power projects worldwide. This design system can be used as a general empirical system to guide the design of underground cavern or cavern group.

In order to research the mechanical properties of deep coal under in-situ unloading stresses，triaxial loading and unloading tests with different unloading rates were carried out on coal under in-situ stresses by using the MTS816 rock mechanics test system and compared with conventional unloading tests. The stress-strain curve was used to analyze the mechanical properties and deformation characteristics of unloaded coal. 3D reconstruction technology by CT was applied to study the failure characteristics of coal. With this prerequisite, the applicable strength criterion of in-situ coal was discussed. The results show that：(1) The peak strengths of coal with two schemes are inversely proportional to the unloading rate. However，the peak strength of in-situ coal is higher than that of conventional coal，and this trend gradually weakens during low-speed unloading. (2) After in-situ stress recovery， as the unloading rate increases， the peak axial strain of coal first decreases and then tends to stabilize，the peak lateral strain remains unchanged，and the peak volumetric strain first decreases and then increases. Under unloading conditions，the elastic modulus of in-situ coal under unloading condition is more stable，making the strain hardening modulus enhanced. (3) The Mogi-Coulomb strength criterion can better reflect the failure strength characteristics of in-situ unloading coal. The cohesion c of in-situ coal increases 39.23% and the internal friction angle decreases 11.92% compared with conventional coal，indicating that the main control factor of failure resistance of in-situ unloading coal is cohesion.

The problem of large deformation of surrounding rock induced by high stresses in the deep stratum poses a great challenge to engineering safety. The typical rock cable would be damaged readily due to its inability to react to the massive deformation of surrounding rock. A new type of steel pipe shrinkable energy-absorbing cable (SPS Cable) was developed based on the principle of steel pipe extrusion and deformation. The SPS Cable fully utilizes the plastic extrusion and deformation characteristics of metal materials and has the advantages of stable resistance，high controllability and good energy absorption effect. The new cable?s dynamic and static mechanical characteristics were investigated by cable tensile testing system and dynamic drop testing system. The test results show that：(1) the SPS Cable can provide a constant working resistance of 367 kN under static conditions，and the maximum allowable deformation can reach 694 mm；(2) When resisting impact loads，the SPS Cable has good energy absorption ability，the buffer force remains stable，and the maximum energy absorption in a single impact can reach 103 kJ. The results reveal that the SPS Cable can offer high support resistance while allowing large deformation. It is very easy to install，and does not interfere with site development. The SPS Cable provided a new solution to deep engineering?s large deformation problems.

In trapdoor tests，ground loss is typically simplified as the settlement volume of the trapdoor. Trapdoor tests are commonly used to study the soil deformation and surface settlement induced by the karst collapse and tunnel excavation. However，the current trapdoor tests are mostly in 2D conditions. Future investigation is needed to understand the progressive development of soil deformation with ground loss in 3D conditions. In this study，dense sand half and full 3D trapdoor tests were conducted using a 12×12 array trapdoor test device with 3 different fill heights. 144 load sensors were used to monitor loading variations during trapdoor settlement in full tests. Laser displacement transducers，which could move on the biaxial linear tracks were used to measure the deformation of the fill surface and later to calculate the surface settlement contour. Laser displacement transducers measured fill surface deformation and calculated the surface settlement contour. The half trapdoor tests were conducted to corresponding the full trapdoor tests and the particle image velocimetry(PIV) technique captured the cross-section deformation behind the plexiglass plate. In this study，the ground reaction curve was calculated based on full trapdoor test results，and the development mechanism of the shear band with trapdoor settlement was evaluated. This study revealed that settlement at different layers from 3D trapdoor tests well matched the 2D Gaussian distribution curve and discussed the relationship between the settlement width and the settlement volume. Additionally，this study proposed a method to predict the surface settlement and ground deformation in 3D trapdoor test conditions. The results of this study can provide guidance for soil deformation and surface settlement in real projects.

To investigate the impact of saturation on the dynamic impact compression properties of freeze-thawed sandstone，red sandstone specimens with saturations ranging from 0% to 100% were subjected to dynamic impact compression tests following 0，25 and 50 freeze-thaw cycles. The findings reveal that，for the same number of freeze-thaw cycles，increasing saturation leads to a progressive deterioration in the dynamic mechanical properties of the rock samples. Similarly，when saturation levels are held constant，greater numbers of freeze-thaw cycles result in diminishing dynamic mechanical properties，characterized by reduced peak strength，heightened peak strain，and increased fractal dimensions. Notably，the influence of saturation on the dynamic mechanical properties of freeze-thawed rock samples is more substantial than that of the freeze-thaw cycle count. When the saturation level is below 25%，the increase in freeze-thaw cycles has a comparatively minor impact on the dynamic mechanical properties of the rock samples. Conversely，when the saturation exceeds 25%，the cumulative freeze-thaw damage within the rock samples intensifies with additional freeze-thaw cycles，leading to a more pronounced deterioration in dynamic properties. As saturation levels rise，internal damage within the freeze-thawed rock samples becomes more severe，resulting in the development of pores，intergranular，and intragranular cracks. This，in turn，amplifies the fragmentation of the rock samples when subjected to impact loads and diminishes energy utilization during impact.

In order to study the evolution of seepage characteristics of oil shale under microwave radiation，high-resolution X-ray CT scanning technology was used to visualize and analyze Fushun oil shale after microwave pyrolysis. The three-dimensional pore structure of oil shale was obtained by 3D image reconstruction technology，and the characteristic information of seepage flow and pressure field was quantitatively analyzed. The results show that：(1) microwave power has a great influence on the pore structure of Fushun oil shale. At 800 W and 600 ℃，the porosity of oil shale is 16.61%. At 400 W and 600 ℃，the porosity of oil shale is 8.42%. The distribution and morphology of pores and fissures are also affected by microwave power. (2) Higher microwave power can improve the fractal dimension and pore aspect ratio of oil shale，make the surface rougher and pore structure more complex, higher porosity，and easier to develop into cracks, which will improve the permeability of oil shale. (3) Through the analysis of medium flow rate value and pore medium pressure value, it is found that the medium flow rate value at 800 W microwave power is 1.25 times the medium flow rate value at 400 W microwave power and 8.68 times the medium flow rate value at 600 W microwave power，and the medium pressure value decreases with the increase of microwave temperature and power. These results enhance the understanding of the thermal effects of microwave radiation oil shale，and find that microwave power has a significant effect on the pore structure and permeability of oil shale.

为合理描述分析脆性煤体在三向应力状态下的应力–应变关系，对煤样进行三轴压缩试验。以已发生损伤破坏的微元体数目与总微元体数目之比表征损伤变量，在基于损伤力学理论和煤样内部微元强度服从Weibull分布的基础上，引入Mogi-Coulomb强度准则表征煤样微元强度随机分布的分布变量，建立煤样三维统计损伤本构关系，并分析其适用性。研究结果表明：(1) 围压对煤样力学性质影响显著，煤样强度和弹性模量随围压的增高而增大，煤样破坏后的裂隙网络分形维数随围压的增高而减小，损伤程度降低；(2) 分析数学简化算法求解模型参数的局限性，采用遗传算法对模型参数进行求解，参数m，F0，cn分别反映煤样的脆性程度、平均强度、残余强度；(3) 根据本构关系对煤样试验应力–应变曲线进行拟合验证，理论曲线与试验曲线的拟合度均值为94.74%，表明本文所建立的本构模型可用于描述煤样的三维应力–应变关系，能够反映脆性煤体的变形特性。

In order to explore the creep behavior and damage evolution law of salt rock under the influence of temperature，the high temperature triaxial creep test machine and acoustic emission test system were used to study the creep deformation characteristics and acoustic emission activity of salt rock at 35 ℃，50 ℃，65 ℃，80 ℃，95 ℃ and 110 ℃. The moment tensor inversion theory is employed to analyze the focal mechanism and microscopic crack propagation mode. The results reveal that the steady-state creep rate of salt rock increases exponentially with the increase of the ambient temperature. The steady-state creep rate of salt rock at 110 ℃ is 35 times as much as that at 35 ℃. In the process of deceleration creep，the acoustic emission activity of salt rock is intense，the impact count rate fluctuates at a high level，and the b value rises steadily. In the process of steady creep，the acoustic emission activity of salt rock is intermittent，and the b value rises slowly and has no obvious fluctuation. The peak frequency of the acoustic emission signal is zonally distributed in a low frequency zone and a high frequency zone. The peak frequency，the proportion of high frequency signal，and b value of acoustic emission signal increase with the increase of the creep environment temperature. The initiation and dominance of small-scale micro-fracture events are enhanced by high temperature environment. The creep slip behavior of salt rock crystals can be effectively characterized by the slip angle of source rupture. The crystal slip of salt rock gradually develops from horizontal direction to vertical direction，while the fracture azimuth strike angle and dip angle are minimally affected by the increase of ambient temperature. The obtained results are of great significance to guide the safety design and long-life operation of ultra-deep salt cavern gas storage.

In the stability analysis of jointed rock slopes，the traditional Sarma method still has the following deficiencies：(1) The direction of the shear force between joint blocks is unreasonably defined. (2) The tensile cracking between joint blocks and their bottom surfaces(i.e.，the slip surface) is ineffectively treated. (3) The requirement that the direction of the shear force on the sliding bottom surface of joint block is consistent with the overall sliding trend of the slope can not be reliably guaranteed. Therefore，the analysis model of the traditional Sarma method cannot fully satisfy the principle of rationality for force analysis. Hence，the following improvements are made on the basis of the traditional Sarma method as：(1) The relation-equation for determining the direction of the shear force between joint blocks under the trend of relative motion is constructed. (2) The technique of tensile strength cut-off is introduced to reliably estimate the tensile strength of rock joints under the linear Mohr-Coulomb strength criterion. (3) The calculation mechanism is established for allowing the tensile cracking between joint blocks. (4) The treatment approach of increasing factor of safety between joint blocks and degrading with the use of cracks on both sides of joint blocks are proposed to reasonably solve the problem of the bottom surface of joint blocks being cracked. (5) The virtual crack at the side of the reverse sliding blocks is set to effectively deal with the case of the reverse of shear force on the bottom surface of slumping joint block. Thereby，the improved Sarma method for stability analysis of jointed rock slope is proposed. Through the comparison and analysis on some existing examples，the reliability and effectiveness of the present method are verified. Thereafter，the influence of relevant new parameters in the Improved Sarma method on the stability of jointed rock slope is further discussed in detail.

Coal burst is an engineering dynamic failure of roof and sidewall system. The research of sidewall bursting failure under the action of roof is more suitable for in-situ geological and engineering conditions in coal mining. By using the developed multi-level changeable stiffness loading test device，the test results of coal bursting liability index under different loading stiffness of the test device were studied. According to the energy supply burst characterization model of the roadway surrounding rock，the bursting energy supply index for bursting risk evaluation was proposed. The results show that with the decrease of the device-specimen stiffness ratio，the post-peak failure velocity of coal is accelerated，and the failure mode of coal is transformed from block cracking and peeling to fragment ejection. The fragment fractal dimension and fracture degree of specimens increase. Testing value of the uniaxial compressive strength and elastic strain energy index have little correlation with the stiffness ratio. The duration of dynamic fracture is positively correlated with the stiffness ratio in a power function，while the bursting energy index is negatively correlated with the stiffness ratio in a power function. The roof supply energy，together with the coal released elastic energy，is an important cause of coal burst. With the decrease of roof-sidewall stiffness ratio，the roof supply energy increases，and the coal bursts more easily. The proposed bursting energy supply index can be used as an important indicator to evaluate coal burst risk under different roof and sidewall stiffness conditions.

Rockburst proneness evaluation provides a basis for rockburst risk assessment in deep tunnels. Based on energy dissipation characteristics of complete stress-strain curve of rocks under uniaxial compression，a new evaluation index for rockburst proneness，the maximum energy dissipation rate(the maximum value of time derivative of dissipated energy density)，was proposed in this study. The rationality of proposed index was explained based on stability criteria，experience，and definition of rockburst proneness. To quantitatively calculate the proposed index，an elastic-brittle-damage constitutive model considering void compaction and initial damage was established. To verify the applicability of the proposed index and damage model，uniaxial compression and cyclic loading and unloading tests were conducted on four different rocks(basalt，granite，limestone and sandstone) under rigid and flexible testing machines. Based on the orthogonal tests，correlation analysis and range analysis，the influencing factors of rockburst proneness and internal relationships between different indices were revealed. The results show that，a maximum energy dissipation rate exists in the post-peak stage of rock stress-strain curve，which can be used as an inherent stability indicator to evaluate rockburst proneness. This indicator can both consider the pre-peak energy storage and dissipation characteristics and post-peak characteristics. The proposed elastic-brittle-damage model effectively describes the nonlinear mechanical behavior and intrinsic energy evolution characteristics of rocks. The theoretical curves of stress-strain and dissipated energy density are in good agreement with experimental values. Calculation results of the maximum energy dissipation rate index for different rocks are consistent with the actual rockburst intensity，verifying the reliability of proposed index. Elastic modulus，brittleness，and initial damage are the main influencing factors of rockburst proneness. The proposed index better reflects the influence of rock brittleness on rockburst tendency， and has the strongest correlation with residual elastic energy index(with the correlation coefficient of 0.940). Research results can provide a scientific basis for the reasonable evaluation of rockburst proneness.

By improving the existing failure approach theory，a safety evaluation index(BRSI) for assessing the mechanical state of brittle rock masses is established，enabling a quantitative expression of the elastic state，strain hardening state，brittle failure and residual state of brittle rock masses. Based on the quantitative relationship between the mechanical state of brittle surrounding rock and the BRSI index，a novel approach is proposed to determine the optimal timing for double-layer primary support during the sequential excavation of super-large section tunnels in brittle rock masses. The proposed method is analyzed and validated through three-dimensional numerical simulations conducted in the Xiabeishan Tunnel project. The results demonstrate that：(1) Under a low confining pressure，tuff undergoes brittle failure immediately upon reaching its ultimate strength. With the increase of the confining pressure，however，tuff shows the characteristics of gradual softening. (2) During tunnel construction，the development of BRSI value of the surrounding rock undergoes three stages as initial development，rapid development and gradual stabilization. (3) The excavation of the rock pillar of the middle pilot tunnel alters the stress state and failure mode of the tunnel wall?s surrounding rock，resulting in the optimal support timing for the middle pilot tunnel lagging behind the side pilot tunnels by 2–10 m. (4) The mechanical state of brittle surrounding rock can be accurately and intuitively characterized by BRSI index，and the proposed method for determining support timing is reasonable and reliable.

To reveal the instability mechanism of deep anchored broken surrounding rock and to explore the internal stress evolution law of the anchored structure under the interaction of support components and gravels，the self-stabilization and reloading model tests of anchored gravels under different pretightening forces were carried out through a self-developed test system. The bearing mechanical properties and deformation failure characteristics of anchored gravels were studied. The influences of the pretightening force on the spatiotemporal responses of internal pressure and bolt anchoring force within structure during the self-stabilization and reloading processes of anchored gravels were analyzed. The mechanisms of self-stabilization and reloading instability of anchored gravels were explored. Based on strengthening the internal force chain network of anchored gravels，a concept of roadway roof fall control was proposed with constant height preload，strong pressure equalizing support，high stiffness and reasonable support density as the core. The results show that the critical pretightening force for self-stabilization of anchored gravels is about 3 N•m. A sudden increase in internal pressure is occurred in the upper-middle part during self-stabilizing process and it spreads outwards to maintain stability. In the lower-middle part，there is a sudden decrease，which is closely related to the redistribution of internal force chain network within the structure. The higher the pretightening force，the more prominent the sudden increase in internal pressure and the less the decrease of the anchoring force. This indicates that high pretightening force is more likely to form a strong force chain network，while low pretightening force result in weak and scattered force chains to damage self-stabilization and loading. During the loading process of anchored gravels，there are frequent and significant stress drops. The larger the pretightening force，the greater the model stress drop，and the maximum loading displacement is generally greater than its peak displacement，and the corresponding load is also lower than the peak load. During the loading process of anchored gravels，the internal pressure behavior is basically consistent with the self-stabilization process，and corresponds to its deformation and failure mode. The dome cavity formed at the center of the lower layer destroys the force chain network，causing the rock mass to spread and fall rapidly along the center of the model to the surrounding areas. The bolt anchoring force decreases continuously with the increase of the loading deformation，and the value of the anchoring force reduction near the central axis of the structure is much greater than that far away from that. High anchoring force is a necessary condition to ensure the force chain network of anchored gravels. The higher the pretightening force，the greater the sudden drop in anchoring force，but after the sudden drop，the structure can still withstand a long time of load.

The whole process of rock deformation and failure has several stages such as compaction，elasticity，plasticity and damage. There are few studies on constitutive models considering rock compaction deformation mechanism under the framework of classical elastoplastic damage theory. In this paper，the rock was abstracted as two parts，the rock skeleton and the rock void. The nonlinear compaction deformation was calculated according to the void deformation mechanism. The plastic deformation characteristics were analyzed using the Drucker-Prager criterion. The damage evolution law was described by the volume deformation. Under the framework of classical elastoplastic damage theory，a compaction-elastoplastic damage incremental constitutive model and its integral algorithm of rock were established. The total deformation of the rock was divided into three parts as compaction，elastic and plastic deformation. The void part cannot bear the shear force and the deformation in each direction has no mutual influence. Therefore，the total strain was calculated in the principal stress direction through the spectral representation of the stress and strain tensors. The numerical integration method was the return mapping algorithm in principal stress space based on Drucker-Prager criterion. The predicted stress was calculated by the compression elastic prediction method. The influence of the compaction strain increment on the total strain increment in one iterative step was analyzed. The compaction-elastoplastic damage constitutive model and algorithm fully consider the non-linear deformation mechanism of voids and compaction deformation characteristics. The proposed model contains ten parameters in four categories including compaction，elasticity，plasticity and damage. It is suitable for engineering rock mass whose void ratio increases and skeleton strength decreases under external action during long-term service. The model was used to study the effect of two typical external environments(dry-wet and freeze-thaw cycles) on rock properties. The results show that the model can well simulate the whole process of rock deformation and failure after external actions，which has certain theoretical significance and engineering value.

To study the blasting vibration characteristics of surrounding rock mass cut by multi-hard structural planes，a field test study was carried out based on the underground powerhouse of Tuoba Power Station. Firstly，the characteristics of rock with hard structural planes and the site construction conditions were analyzed. Then，based on the engineering site conditions，a blasting vibration test program was designed for the underground powerhouse and a blasting vibration field monitoring test was carried out. The study shows that the attenuation law of peak vibration velocity in surrounding rock cut by multi-hard structural planes is jointly affected by the proportional distance(the cube root of the blast core distance to the explosive quantity) and the structural plane dip angle. A significant nonlinear relationship is showed among them. Also，the influence of structural plane dip angle on the blasting vibration characteristics was focused on. The blasting vibration law of the surrounding rock mass about different dip angles of single structural plane and the proportional distance was studied. Thus，the corresponding calculation formula was proposed. With these results，based on the theory of safe vibration velocity，the safe distance of the surrounding rock cut by multi-hard structural planes in the underground powerhouse was studied. Finally，the study results were practiced for engineering application.

After excavation and unloading of deep soft rock tunnels under high in-situ stresses，the radial stress of the surrounding rock will decrease sharply，indicating that the confining stress will decrease sharply from deep to the tunnel wall. The strain-softening behavior and the shear-expansion behavior of rocks at different locations are controlled by the confining stress effect. In this study，based on the three-dimensional H-B strength criterion，a computing method for the elastoplastic solution of deep soft rock tunnels considering both confining stress effect and medium principal stress was developed. It was employed in the Xinhua tunnel of the China—Laos railway to calculate the squeezing deformation of deep buried tunnels passing through red layer in Yunan. Further，the influences of confining stress effect on stress-strain characteristics，strength-softening characteristics，and shear-expansion characteristics were discussed. Besides，the sensitivities of confining pressure effect under different peak rock strengths，in-situ stress，and supporting force were also learned in this study. The conclusions of this study are as follows：The confining stress effect can reduce the critical plastic deviator strain( ) and increase the peak dilatancy coefficient( ) of rocks. Thus it can improve the degree of strain softening and dilatancy capacity. Then the squeezing deformation will be intensified. The medium principal stress will reduce the strain softening and increase the shear expansion of the surrounding rock. However，it can restrain the squeezing deformation of deep soft rock tunnels in general. When tunnels are constructed under a situation with low peak rock strength and high in-situ stress，the squeezing deformation is seriously affected by confining stress effect. Therefore，the confining stress effect cannot be ignored when analyzing the mechanical response of deep soft-rock tunnels under high in-situ stress. The support force can suppress the confining stress effect on the squeezing deformation of tunnels. Thus，during the construction of deep soft rock tunnels，support structures should be installed in time. So the deformation of the surrounding rock can be well restrained after excavation.

A set of indoor model test device for gravel pile composite foundation was fabricated，and 11 groups of indoor model tests of reinforced gravel pile composite foundation and 2 groups of unreinforced comparison tests were carried out. The composite foundation bearing capacity，pile-soil stress ratio，bearing capacity improvement rate and pile bulge deformation under different parcel lengths，reinforcement spacings and reinforcement combination methods are researched. The test results show that compared with the traditional gravel pile，the bearing capacity of the composite foundation is significantly improved by reinforcement，and the vertical reinforcement effect of the full-length wrapped is the most significant. The reinforcement method with larger composite foundation bearing capacity improvement corresponds to larger bearing capacity improvement rate and pile-soil stress ratio. The improvement rate of bearing capacity increases with the increase of reinforcement length and reinforcement spacing. The pile-soil stress ratio of the composite foundation fluctuates with the increase of settlement. And increases with the reduction of reinforcement spacing and the increase of reinforcement length；There are some differences in the deformation law of pile body under different reinforcement methods. The bulging deformation of pile body with full-length wrapped vertical reinforcement method is relatively uniform and the deformation is small，which has better effect on improving the bearing capacity of composite foundation and inhibiting the bulging deformation of pile body.

A series of triaxial compression tests involving saline condition and degree of overconsolidation are carried out to investigate the influence of type and concentration of pore solution and overconsolidation ratio(OCR) on the stress-strain curve，dilatancy behavior and other mechanical properties of saturated clay. The test results indicate that the change of the type and concentration of pore solution can change the degree of overconsolidation，deformation capacity，dilatancy ratio and slope of critical state line of clay，but it has little effect on the elastic modulus. Therefore，a new chemo-elastoplastic model is established based on UH model to simulate mechanical behavior of saturated saline clay. This model considers the impact of osmotic suction on clay?s mechanical properties and can describe its stress-strain behavior under different saline conditions. The new model introduces equivalent stress to define osmotic suction?s contribution and presents a chemical elasticity theory for saturated saline clay. Additionally，the yield surface，hardening modulus，stress-dilatancy equation and constitutive relation of saturated saline clay are derived by considering osmotic suction effects. It is observed that increasing osmotic suction leads to a“shorter and fatter”yield surface in three-dimensional stress space for saturated saline clay while reducing overconsolidation degree but increasing dilatancy ratio gradually. The universality and prediction ability of this model are verified by simulation and comparative analysis of test results of saturated saline clay under different osmotic suction.

Dredged mud slurry has the characteristics of high water content，low or negligible strength and low hydraulic conductivity. Rapid and efficient treatment and utilization of these slurry are of great significance. This paper conducted a series of experimental to study the rapid treatment of high water content slurry using the combined method of prefabricated horizontal drain vacuum preloading and chemical solidification(abbreviated as PHDVPS). The solidifying agents used in the experiment included magnesium oxide(MgO)-activated ground granulated blast furnace slag(GGBS) and Portland cement. The treatment effect and efficiency of the combined method were compared with those of pure vacuum preloading method. Variation of discharged water mass and slurry volume were monitored during the vacuum preloading stage of the model tests，after which the unconfined compressive strength (UCS) of soil samples at different curing ages was tested，and the microstructures of the treated soils were analyzed. The experiment results indicates that PHDVPS method has a significantly better volume reduction efficiency and a significantly better reinforcement effect than the pure vacuum preloading method. The solidifying agent produces flocculation effects，which improve the vacuum dewatering efficiency，leaving the subsequent solidification process occurring in a denser state of soil matrix and thus achieving much higher strength. Moreover，using GGBS-MgO as the solidifying agent in PHDVPS method has better volume reduction and strength improvement effects than using cement.