Under the condition of no cubic strain, the loading-deformation relational expressions of wall rock are obtained according to simple loading characteristics of wall rock of tunnel. The relational expressions are simultaneously related with triaxial stress ( and ) and triaxial strain ( and ) in wall rock, and they are expressed by equivalent stress, , and equivalent strain, . The stress or strain state of elastic zone, hardening zone, softening zone and flowing zone of wall rock of tunnel are respectively corresponded with the stress or strain state of different stages of equivalent stress-strain curve, and they have strictly been demonstrated. Supposing equivalent stress, , and equivalent strain, , are regarded as middle variables, can the elastic and plastic analysis of surrounding rock be simplified, and can the calculation expression of deviatoric stress-strain energy generation of tunnel surrounding rock is written forthright. Equivalent shearing stress, , is the most shearing stress, , in wall rock. Equivalent shearing stress unit is acted on by the direct stress and shearing stress, but it only has shearing strain. This emphasizes an essence that the deformation and fracture of wall rock of tunnel are resulted from the most shearing stress and biased stress-strain energy. The determined slipping line based on equivalent shearing stress conception can be applied to strain hardening and softening stages of the materials and needn’t require the supposition condition of rigidity-plasticity.

Besides strength parameters of soil, earth pressure is also related to stress path. For instance, when vertical stress keeps constant and lateral stress decreases to a critical stress, earth pressure is in the critical active state. The process of passive earth pressure is opposite. The active and passive failure tests of soil in triaxial test with stress path control are simulated. The relationship of stress strain of the typical stress path is discussed; and the relationship between earth pressure and lateral strain is presented. The results of test and calculation are compared. It has been found that the active earth pressure is well simulated by the proposed equation, but not for the passive pressure.

Storing petroleum in large underground caverns is an important way of strategic petroleum reserve in the world. With the increase of imported petroleum in China, constructing large underground petroleum storage caverns is no doubt a project with better comprehensive economic effect. According to the engineering characteristics of the large underground water-seal petroleum storage caverns, the excavation sequence and construction method of underground petroleum storage caverns are simulated by using numerical method. Three potential schemes of construction are analyzed and compared. Through their calculating results, including the surface settlement, the deformation of key points on the cavern boundaries, the distributive laws of the stress field and displacement field due to each excavating scheme, are studied and contrasted; the optimum construction scheme is chosen from the above schemes. The viscoelastic numerical simulation is performed for the construction process of the optimum scheme; and the deformation characteristics of petroleum storage caverns is given by considering the rheologic behaviors of rock mass. The Strength and the long-term stability of underground petroleum storage caverns are analyzed and evaluated; and the obtained conclusions have a certain referential value for the sequence of excavation and construction of underground petroleum storage cavern.

It is a traditional method that box-shaped and egg-shaped buried culverts are designed with given load. The method does not consider interaction between soil and culverts. But in fact, load acting on culverts is changed with relative stiffness of culvert and soil. So a new analytical method for egg-shaped and box-shaped buried culverts is advanced. Winkler model is used for the model of interaction between pipeline and soil commonly. Transfer matrix method is adopted. By the method, the internal force and distortion of pipeline is calculated and its importance is proved to consider soil retained to some stiffness pipe. Finally, it is discussed that model parameters, buried depth and pipe dimension affect to structural distortion and stress. Accordingly, it is more consistent with reality to design culverts by considering interaction between soil and buried culvert pipe.

Gravelly soils are made up of gravel, cobble, sand and cohesive soils. They have been widely used in engineering applications such as earth-rock dams impervious fillings and stub cutoff walls. Present researches are mainly aiming at these engineering applications; researches on fine grained soils of the loose gravelly slopes running off under rainfalls, making structures of the soils alteration and affecting their mechanical properties or even affect the slope stability, are few order to study the erosion process and features of the gravelly slope soil under rainfall conditions, this essay carried out a sort of artificial rainfall local and model experiments; and the water content and sediment content of the runoff is monitored in the experiment. Result shows that the shapes of the slope surface transformed phasicly; runoff producing rate and erosion modulus increases linearly with lengthening of slope length. Runoff quantity increases along with the time of the rainfalls with the character of hopping and fluctuating, sediment content descents adapt to the rainfall time with the character of approximate power function.

The affecting factors and sensitivity of the displacement fields produced by the shield tunneling across the ultra-near tunnel obviously differ from that of the general construction. Combining the metro tunneling examples within ultra-near distance (1.05 m)in Shanghai, It is found that the earth pressure varies significantly while shield approaching to adjacent metro tunnel in operation situated overhead. Based on the principles of tunnel loading model and theory of elasticity a, theoretical formula of earth balance pressure of shield was deduced and a so-called “step control strategy” was concluded which was successfully applied in a typical project of Shanghai metro tunnel line No.4 of which the maximum displacement was controlled within 5 mm. The field measurements of earth pressure proved to be at good coincidence with the theoretical values.

Landslides, that occurred on steep slopes along highway routes, always cause traffic stagnation, even endanger property and human life. For doing maintenance work effectively and avoiding disaster，it is essential to assess stability of road slopes. In this study, the large research area is firstly divided into slope units, which are used as the objectives of the three-dimensional deterministic model. Then a random searching method is used to locate the critical slip surface of each slope unit. The critical slip surface with the minimum safety factor is calculated by a GIS-based 3D slope stability model. The failure probability of each slope unit is calculated and landslide hazard degree of the studied area is zoned quantitatively. The methodology is illustrated by a probabilistic slope analysis of the 49th national road in Gouto area of Japan.

The ground by partially penetrated sand drain is turned into a equivalent-double-layered ground with the general solution of the average degree of consolidation; and the analytical solution of 1-D consolidation for the underlying soft layer is given; and furthermore the average degree of consolidation is obtained. Based on this solution and the present existed solutions, these relevant programs are programmed. The influence of c and soil property parameters on the consolidation process is investigated; and the relevant results are prepared in graph forms; and the applicabilities of all these solutions are evaluated. It is shown that the solution in this paper fulfills the requirements of project. Especially in the case of PTPB, the curves of Uz-Tv are more actual which drawn by this solution in comparison with the others.

The dynamic compaction finite element equation and the numerical analysis method of soils subjected to the impact loading are established. Ansys-Ls-dyna software is used to analyze the soil dynamic response of Shanxi Fertilizer Factory's layer soils subjected to the impact loading. The distributed characteristics of displacement and its change courses are studied and compared with experimental figures. It proves that the calculation results approximate the experimental data. It results that the displacement influence scope of the impact load in the soils is an ellipsoid. The lateral reinforced radius from the center of loading is 2D (D is a the diameter of tamping hammer), the reinforced depth under the center of loading is also 2D or larger.

Seepage is ubiquitous during excavation in high groundwater table. Analytical formulas for calculating the water head in active and passive zones of foundation pit are derived under the assumption that the seepage is one-dimensional and steady. The influence of seepage on the effective stress and the heave of foundation pit base is analyzed through a numerical example. It is indicated that seepage causes the decrease of effective stress and thus the increase of heave of soil mass beneath foundation pit base.

Natural sedimentary ground deposited in the north shore of the Yangtze River delta mainly consists of silty and fine sandy soils. The permeability varies within 10-7-10-3 cm/s, less than the order of 10-3 cm/s responsible for completely drained condition but larger than the order of 10-7 cm/s responsible for completely undrained condition. Little study has been carried out on such natural intermediate soils in China. In this study, a series of physical and mechanical tests were performed on both the undisturbed and the remolded samples obtained from three sites in the north shore of the Yangtze River delta along Tongqi highway. The results indicate that the physical properties are similar to natural clayey soils with moderate sensitivity, but the tip resistance obtained by the in-situ cone penetration tests is almost the same as that of stiff clayey soils with liquidity index almost equal to zero. This study also illustrates that the grain size distributions of natural sedimentary intermediate soils have a significant effect on tip resistance. The grey correlation analysis utilized to analyses correlation between physical state index and mechanical character index for this clayey intermediate soils. It is clearly discovered that the void ratio utilized for sandy loam consistency partition and water content ratio for the silty clay and the clay consistency division are much more rational.

The interaction coefficients of pile group were usually analyzed with plane strain model, which had too many assumptions. Based on a more rigorous model of imaginary piles, integral equation approach for piles group interaction was applied to analyze the effects of piles reinforcement in soil. To simplify the analysis, two piles model was given. Compared with the elastic theory method and Mylonakis & Gazetas method, it shows that the effects of piles reinforcement in soil had obvious influence on the interaction coefficients of pile group. Finally, some defects of Mylonakis & Gazetas method based on the shear force-displacement model are pointed out.

To avoid making barriers for follow-up engineering and save from a trouble of law, the temporary anchor rods of foundation pit brace should be removed when them have no effects. After some analyses of load transfer behavior of anchor rod, and based on the results of field test, a type of technique of removable anchor for which the pull rod can be removed, is proposed. By setting separation layer between pull rod and slip casting body to remove pull rod, and by setting bearing body with pole to disperse load to slip casting body, this technique is realized. Actual engineering example shows that this technique is easy and feasible. Because of the stress in removable anchor rod is reasonable, its technical characteristics are higher than traditional anchor rod too.

Some parameters in the design of multipropped deep foundation pit are analyzed; and the selection of flexibility parameters of prop and retaining wall is compared. Using FEM, an orthogonal design test of the excavation of deep foundation pit is carried out considering 4 levels of the prop stiffness, displacement flexibility number; elasticity modulus and so on, and the influences of these parameters on the excavation deformation are obtained. It is concluded that the displacement flexibility number of retaining wall is primary parameter which controls the deformation of foundation pit; other parameters, such as stiffness of soil, etc., have little influence on deformation of deep excavation.

Testing studies is made on the mechanical properties of rock salt after undergoing different high temperatures, The mechanical properties include stress–strain curve, peak stress, peak strain, modulus of elasticity. the results indicate that the temperatures is obviously affect the mechanical properties of rock salt, the mechanical properties deteriorate rapidly along with the increase of temperatures, the peak stress and modulus of elasticity decrease rapidly, the peak strain increase rapidly. The peak stress is a power function of confining pressures and temperatures. Based on the relation of elastic modulus and temperatures for rock salt, the thermal damage evolution and one dimensional TM coupled damage constitutive equation are established

Shear strength parameters are most important factors to evaluate the stability and economical efficiency of a geotechnical project. One of the most effective and mainly used ways to estimate the shear strength parameters is linear regression method. The shear strength parameters can be calculated either by regressing maximum shear stress with average normal stress or regressing maximum principal stress with minor principal stress. The equations to apply these two methods are introduced, These methods and moment method are applied to calculate the shear strength parameters of core clay in Xiaolangdi Dam with 320 triaxial tests and clay of several other embankments; and the results show that the cohesive strength is underestimated and friction strength is overestimated by regressing maximum shear stress with average normal stress will the standard deviation and relation coefficient decreased when the sample size increased. The theoretical analysis also reveals this trend. The theoretical analysis based on probability also reveals that trend. So the method regressing maximum principal stress with minor principal stress not regressing maximum shear stress with average normal stress should be chosen when estimating shear strength parameters from conventional triaxial tests.

Based on the principle of support vector machine, a classification model of expansive soil is established. Meanwhile, the classifying blocks of expansive soil are obtained through training a large set of expansive samples. Then, a prediction for the classification of residual expansive soils has been carried out using this model. The researching results show that the classification model of support vector machine presents excellent performance, high prediction accuracy and is easy to run. As a result, it is an effective way and has wide applying prospect.

The anti-pulling mechanism of soil-nailing supporting system in foundation pit is analyzed and discussed; and a new viewpoint about anti-pulling mechanism is put forward. Anti-pulling force in soil-nailing supporting system mainly originates from two parts: the nail-soil interaction and the self-supporting of soil. In the supporting system, soil-nailing, as a force transfer component, firstly transfers the anti-pulling force originating from the self-supporting of soil; then gives other force by the nail-soil interaction. The total anti-pulling force in the supporting mechanism is determined by solving theoretically the two anti-pulling forces respectively. Finally, an engineering case is introduced to prove the reasonability of the anti-pulling mechanism; and its theoretical solution is suggested.

Based on the generalized Darcy’s Law and theory for spherical diffusion model, a formula for calculating the effective diffusion radius of exponential fluids injected into homogeneous sandy stratum in grouting is deduced . It shows that the grouting pressure difference is related to the grout rheology parameters c, n and the diffusion radius. The grouting pressure difference change with c by linearity rule and with n by nonlinearity rule. Grouting pressure difference increases with increasing radius, and the increasing grades are notably affected by the grout rheological parameters.

The Asaoka method has often been used to predict the post-construction settlement in geotechnical engineering and the consolidation coefficient can be calculated with the quantitative expression of consolidation coefficient Cv versus the slopeβ1 of the Si-Si+1 straight line in the Asaoka’s method based on the observed settlement data. However, it has been reported that the back-analyzed consolidation coefficients with the Asaoka’s method are not consistent with the in-situ one. This study investigated this discrepancy, and propsoed a new method for calculating the consolidation coefficient based on one-dimensional Terzaghi’s consolidation theory. The back-analyzed consolidation coefficients with the new expression are quite consistent with the in-situ one.

At present, people often predict soft-ground settlement with the method of exponential curve and double-curve extent; but the result is not ideal. The application of neural network to that exists some limitations. GM(1,1) model has been applied to this field, but all the equal-time settlement data model do not explain definitely interpolation method in existed case. The paper takes the predicting the soft ground settlement of Xibu tunnel filling sea project in Shenzhen for example, discusses the way to solve the problem through building the BP neural network-grey system united model; constructing the equal-time settlement time series data by BP neural network nonlinear interpolation method, on the basis of it, building the time series GM model for settlement, and building the time function to predict the settlement. The case study shows that the model is quite accurate in short-term settlement prediction, its long-term settlement prediction also has some project referential value.

The support system of foundation pit is divided into three isolated models related by their boundary conditions, which include active soil around support structure, support system and passive soil under the bottom of the pit. As plane strain problem, the active and passive soils are meshed as solid elements, support piles are meshed as beam elements. If the piles worked with bolts or struts, the bolts and struts are meshed as truss elements connected with beam elements. Then each model could be solved respectively; but share common boundary conditions. Giving the initial condition as the horizontal displacement of the piles equal 0, then the displacement could be solved by iterative method. If the displacements between two loops are nearly same, the iterative process ended; and the forces and displacements of the piles in stable state could be achieved. Displacement iterative method objectively reflected the dynamic interaction process between soil and support structure. This method is applied to an actual case; the calculating results are well coincident with the measuring data.

An incremental constitutive realtion is established based on the generalized plasticity through analyzing the plastic properties of collapsible deformation of loess. The moisture content of increasing dampness is regarded as an internal stress, and the collapsible volume yield surface and the shear yield surface are obtained through tests fitting; at the same time, the initial yield surfaces of collapsible deformation are given. It is shown that the model can reflect the properties of collapsible deformation under the different collapsible effects; and considering the collapsible volume deformation shear deformation and the influence of spherical stress and deviatoric stress to them.

Oil-based drilling fluids, saturated/under-saturated saltwater drilling fluids were generally introduced to salt/gypsum stratum according to mechanics and physics analysis. But oil-based drilling fluids cannot be applied cosmically because of itself limitation. And accidents and complex situations take place frequently by adopting saturated/under-saturated saltwater drilling fluids. Under acceptable drilling fluids cost condition, hole in salt/gypsum stratum can be stabilized that under-saturated organic salt liquor drilling fluids with proper density can satisfy the condition that formation salts are solved appropriately and keep better drilling fluids inhibition. Two drilling fluids are prepared by organic salt based solution density of 1.30 g/cm3 and 1.36 g/cm3 respectively; and their routine properties, resistance to fouling, and inhibition are evaluated in lab. The conclusion of experiment is that two drilling fluids can achieve the need of drilling salt/gypsum stratum; and the two drilling fluids were applied to Y5-2 well for a field experiment. Results show no fault and less drilling cost compared with other wells in the same structure.

Based on dissipation of 3-D excess pore water pressure due to static pressed pile in soft clay, consolidation of the clay around the pile and failure model of pile-soil interface, an analytical solution to estimate time-depended ultimate bearing capacity of the static pressed pile was obtained. To static pressed pile in soft clay, the presented solution shows that the ultimate bearing capacity of 50 d may reach 70 % that of the final capacity. Results from the presented solution are in agreement with site tests.

Semi-rigidity base materials have been widely used in China for a long period; and now cement stabilized aggregates is the main one. Low dosage cement stabilized aggregates road base is similar with it but the cement dosage is less, so the performance of economy and preventing cracking become better. Firstly, how the percentage of various dimension granule influent the intensity of this material is analyzed secondly, the curve about the relation of intensity and dosage of cement is made, which is based on the same percentage of various aggregates; at last, through comparing the CBR and intensity of various dosage cement stabilized aggregates, the probability of using low dosage cement stabilized aggregates is confirmed.

The average particle gradation can be obtained after sieving the local gravel-soil from the Three Gorges Reservoir area, and then its experimental particle gradation is designed with replacement method. According to the feature of gravel-soil, the water content of sample is controlled by granule soil content and sampled under the same vertical pressure. The following conclusions are drawn on the shear strength and parameter of gravelly soil with different water contents and different rock contents: with different water contents, the critical rock content with changed strength will be different; with different rock contents, c value changes little with water content, while ? value changes remarkably; the internal friction angle changes with different rock contents, probably reducing by 3° -10° or so, when gravelly soil changes from the original condition to its saturation. These conclusions uill to be a basis for estimating the carrying capacity reduction of overpass and roadbed after the Three Gorges Reservoir filling.

The electrical resistivity testing technology is presented to research the structural characteristics of cemented soil quantitatively. To describe the change of the resistance, three electrical resistivity indices: average structure factor F, average shape factor f and anisotropy factor A; are introduced. With the measure of vertical and horizontal resistance during the compression test, the electrical resistivity indices of cemented soil are concluded. Then, the relationship between the electrical resistivity indices and physico-mechanical characters is analyzed. The results show that it is effective to research the soil structure by the electrical resistivity indices.

The mechanical behaviour of shield tunnel construction beneath adjacent existing highway tunnel is studied by using three-dimensional finite element numerical simulation method. The research demonstrates that it is dangerous to increase jack forces of the shield machine across adjacent upper existing highway tunnel which is considered as a kind of unloading structure. In addition, the jack forces of the shield machine is needed to be drop down to the limit value at 6 m distance from the edge of upper existing highway tunnel and the measurement of the existing highway tunnel floor is enhanced in advancement process of shield machine to guarantee the safety of upper existing structure.

Excavating stability of tunneling in permafrost region is related to deep and shallow stability of wall rock. Excavation method is selected by analysis of deep stability. Shallow stability analysis can appraise excavating safe status to guide construction. Real-time controlling system measures convergence and temperature of tunnel, and makes the deep and shallow stability appraisement systems related to tunneling; so construction control and prediction of tunneling come true in permafrost region.

Based on the improvement practice on the reclaimed land on the site of express mail disposal center of Pudong International Airport, the construction technology of improving hydraulic silty fine sand and saturated soft clay on the reclaimed land with DDCM (dynamic and drain consolidation method) is presented. Combined with testing of properties of soils before and after improving, the field test results on the testing area for dynamic consolidation on the hydraulic silty fine sand show that it is feasible to improve the saturated soft clay on the reclaimed land with the new construction technology of low-energy and “fewer times and more cycles” dynamic compaction combined with the plastic vertical drain. The mechanical property and deformation characteristics of saturated soft clay on reclaimed land are improved obviously after improving with the new technology above mentioned. It has been achieved to use hydraulic filled silty fine sand as the dynamic consolidation cushion in this project. The investment has also been reduced largely with the use of hydraulic filled silty fine sand instead of mid-coarse sand as the cushion for dynamic consolidation. The test results of the improving construction on the large area of reclaimed land show further that the improvement effect of DDCM on reclaimed land is remark.

Guishan ancient rock slide, bulking about 2 100×104 m3, lies above water inlet/outlet of lower reservoir of Baoquan Pumped Storage Power Station. The stability of the slide evidently affects safety of the pumped-storage power station. The paper first discussed boundary conditions and parameters on slide surface of the ancient slide, pointing out problems that should be paid attention to in stability analysis of ancient rock slide. Stability of Guishan ancient rock slide was then calculated by 2D (limiting equilibrium) and 3D (Flac) methods. Based on the calculations, remedy methods were finally suggested.

Two test piles with the same diameter for the Jili-Yellow River Bridge were tested with the self-balanced test and the anchored pile method respectively. According to the contrast of average shaft resistances of two piles, the regularity of the relationship between settlement and average shaft resistances is similar, they could be fitted with the hyperbolic model. While settlement is 12 mm, the average negative shaft resistance is 0.84 times of the normal one. The Q-S curves is very close in the first part, but with the increase of loads , the descending rate of the curve of S1 is faster than that of S2. While settlement is 30 mm, the capacity of S2 is 59 500 kN，the capacity of S1 is 48 000 kN. The ratio of base resistance of S1 to the total load is 22.46 %, this pile is a friction-base pile; the ratio of base resistance of S2 to the total load is 3.59 %, this pile is a friction pile.

In loess foundation engineering, it is often necessary both to eliminate the collapsibility and increase the bearing capacity. down hole deep compaction is a relative new foundation treatment method. The analysis of tests results, including in-situ single piles loading tests, loading tests on soils between piles and other tests, illustrates that the down hole deep compaction is an effective foundation treatment method to eliminate the collapsibility of loess, increase the bearing capacity and improve the behavior of composite foundations.

The continuous cut-cast pile is adopted for the foundation pit of Shipaiqiao Subway Station in Guangzhou city. The optimal calculation has been made for the sparse piles with 2.0 m distance between the neighboring piles of ? 1 200 mm while the foundation safety is guaranteed. The monitoring design is brought out in detail in order to guarantee foundation safety on account of complex environment around the foundation; the comprehensive data are gotten and used for construction.

The phenomenon of large-area rockmass failure has been observed in Daliushu dam site on the Yellow River. In order to study the failure mechanism of this rockmass, the intrinsic relationship between dynamic effect of earthquake and rockmass dynamic failure is put forward on the basis of detailed investigations of regional geological environments and regional seismic dynamics; and dynamic simulation experiment are conducted on the failure phenomenon. The experimental results show that the large-area rockmass dynamic failure in Daliushu dam site area is closely related to the meizoseism history. Consequently, the dam site would be damaged more seriously once the seismic activity of the same scale happens.

In the soft ground treatment process of Xiamen Haicang Road, flat dilatometer test (DMT) is applied to get mechanical property of soft soil. From the DMT data and the comparison with several other in-situ tests, a conclusion can be drawn that DMT is simply to operate, can make less disturbance of soil and get many mechanical parameters exactly. The DMT for a soft ground treated with two different methods shows that the preloaded sand drain can obviously improve mechanical capacity of soft soil; the treatment effect will reduce while depth increase; and the cement injection pile has very little influence of the mechanical property of soft soil from a comparative long time.

Indoor and outdoor experiments on the characteristics of the cement added fine sands for Shifosi Reservoir were carried out. Experimental results show that; with the increase of cements, the cohesive force and friction angle increase; the percolation coefficient decreases. When the volume ratio of cement and fine sands is 2 %, shear strength and percolation coefficient are improved obviously. The properties of fine sands are improved when they are combined with cements, so using them in embankment is possible.