Based on the theory of upper bound limit analysis, the velocities of the nodes are regarded as unknown quantity, with the conditions of flow rule, velocity discontinuity, velocity boundary, the energy-work balance equation, the linear programming model of stability of slope subjected to pore water pressure are established. The pore water pressure is considered as an external force. Then the upper limit value of the safety coefficients of slopes, and the corresponding kinematically admissible velocity fields are obtained. Finally, using the proposed method，the stability of two classical soil slopes are calculated; and the results demonstrate the correctness of the method.

The method of dynamical numerical analysis is used to analyse the movement of grains on slope; and the research is based on in-situ observation and model tests. First, there are two main movement patterns, slide and roll. And these two movement patterns can converse each other. The movement can be caused by pull or push forces. On the pull-surface, most of grains move in rolling pattern and the roll will be driven by the movement of sands on the top or in front of them. On the push-surface, most of grains move in slide pattern and the slide will be driven from the top or back of them. Then, based on the driven force conditions of a grain of sand, the movement parameters and dynamical model of sand in sliding, rolling and crash are derived.

It has been well recognized that the safety of embankments during earthquake cannot be evaluated solely by the safety factor of the pseudo-static stability. It is suggested by Newmark that the seismic stability of embankment should be assessed by using the seism-induced sliding movements or permanent deformations instead of the overall safety factor. However, the rational evaluation of sliding movements or residual deformations induced during earthquake cannot be made in a perfect manner. In this paper, a numerical procedure is proposed for evaluating the sliding movements of embankments based on the step-by-step dynamic response analysis and the pseudo-static limit-equilibrium analysis. In the proposed method, the dynamic responses of embankments to earthquake shaking are first predicted by FEM-based numerical analysis. The simplified Bishop’s procedure and modified simplified Bishop’s procedure of limit equilibrium are employed to evaluate the transient safety factors of potential sliding mass of embankment slopes respectively for circle slip surface and for smoothed non-circle slip surface. For the overloading in which the transient safety factor is lower than unity; the transient sliding movement can be assessed by double integration with respect to time. For the example case, the parametric computations and comparative studies are made to examine the effect of vertical component of ground motions, vertical seismic response of potential sliding mass, shaking-induced pore water pressure and other related factors on the sliding movement and earthquake-resistant behavior of embankments.

Because of the special mechanical properties of rock salt can be used for the energy storage and waste (radioactive and toxic wastes) disposal. But one of the properties of deep ground is “high temperature” and the temperature plays very important role of the rock salt mechanical properties, especially rising temperature. Testing with the Yingcheng rock salt during rising temperature (without confining pressure, 20-270 ℃) using ultrasonic wave. From the experimental data, the velocity of ultrasonic wave, the modulus and the Poisson’s ratio of dynamics decrease during rising temperature, but their trend is different. Dynamical elastic modulus decreases fast and the dynamical bulk decreases slowly. The relation of the ultrasonic wave velocity and the dynamical modulus between temperature can be expressed by functions. Both of experimental phenomenon and the data reveals that, the thermal damage and the relative align microcrack density parallel to the axis of specimen evolution with the temperature, but the rate is attenuating when the temperature rising. There is no phenomena indicates the “critical temperature” and damage self-healing due to the temperature.

The theoretical analysis and test indicate that sullage soft soil has viscoelasto-plastic rheological characteristics under dynamic loading. Based on this, the viscoelasto-plastic rheological model is established, and a new rheological equation and dynamic rheological parameters are deduced. The research conclusions have important theoretical significance for us to analyze rheological dynamic response and stability, rheology dynamic mechanism of leading geological disaster, and also for us to keep geotechnical engineering security.

The equations of the theories in previous paper are deduced for rock under triaxial compression.An example of presented models is gived. The example shows that the constitutive model can reflect the mechanical properties caused by the frictional sliding, mode-Ⅱ self-similar growth and kinking of closed microcracks under compression and swelling distortion caused by shearing. The opening of partial microcrack during kinking makes seepage increasing.

The mechanical behaviour of intersection of horizontal adit and main tunnel in Wanxian to Liangping expressway in Southwest China is studied by using 3D finite element numerical simulation method and in-situ test. Due to adit construction, the research demonstrates the disadvantageous distribution of deformation and internal forces in intersection of adit and main tunnel, particularly in its side-wall connected to the adit. Comparing with the case of no adit, because of arch tunnel set being broken; the intersection structure is subjected to combination of complicated stresses including transverse stress, but not the axial stress. Therefore, it is necessary to take some reasonable reinforcement measures to guarantee safety of the intersection of adit and main tunnel. Furthermore, the intersection angle is more small, the stress concentration of intersection is more high. For example, while intersection angle is 60 degree, the maximum coefficient of stress concentration is up to 1.95; but while intersection angle is 90 degree, the maximum coefficient of stress concentration is about 1.5. The results are helpful for designing and construction of intersection of main tunnel and adit in major highway tunnel.

The piezomagnetic overcoring method is an in-situ stress measurement technique that developed since 1950 s. In order to implement three dimensional stresses measurement in a single borehole, the total stresses sensor has been developed. The structure and calculating theory of piezomagnetic total stresses sensor are introduced. The comparing study of in-situ stress measured has been carried among the piezomagnetic overcoring method using several inclined boreholes which are oriented in different directions, piezomagnetic method in single borehole and hydraulic fracturing at Jinping Ⅱ Hydropower Station. The measurement result indicate: in-situ stress at shallow depth of tunnel is controlled by deadweight, topography and region formation, formed typical stresses distribution of V-shaped river valley; the maximum stress is about 11 MPa and the direction is about NNW. The in-situ stress at deep depth of tunnel is higher, the maximum stress is about 40 MPa, and the direction is about vertical. The direction of maximum stress changes from level state to vertical state along with increasing of level burying; and it indicates that the deadweight stress is dominant effect. After comparison of in-situ stresses measured, it is shown that they are consistent fundamentally. We consider the piezomagnetic overcoring three dimensional stresses measurement method in a single borehole can provide reasonable in-situ stress information as same with the piezomagnetic overcoring method and hydraulic fracturing using several inclined boreholes which are oriented in different directions.

With the increase of the traffic and the over-load vehicles, the failure of the subgrade retaining structure is always being reported. For a failure earth retaining wall of the Renminglu grade separation bridge in Hezhe City of Shangdong Province, the dynamic effect of the vehicles has been firstly analyzed. Based on the finite difference method of FLAC, the failure mechanism and the failure development under the dynamic vehicles load have been researched. It is concluded that the effect of vehicles dynamic load is a time-spatial process, and the displacement of the strip net induces the wall failure. The failure mechanism of the retaining structure can be shown as the tensile failure in the upper part and the shear failure in the lower and medium parts. At the same time, a comparing study on the height of the retaining wall and non-symmetric dynamic load has been done. The result indicates that in the reinforcement of the failure retaining wall both controlling the deformation and increasing the soil strength are important for a comprehensive engineering project. The conclusion of this paper will be a useful reference for the analogous failure of earth retaining structures.

The giant pile group foundation of the Su-Tong Bridge located on the Yangtze River is selected to be the subject investigated. The seismic excitation is regarded as stationary stochastic process considering the uncertainties of real seismogram. A stochastic seismic response method, in which the complex response technique is employed, is applied to study the dynamic responses of this pile group foundation with a large pier cap. The dynamic nonlinearity of soils is considered through the equivalent linearity method. During a seismic motion, the displacements along depths of pile shaft appear triangle because of inertia force of pier and weak restraint of soft soil. The displacement of soil is related to the distance between soil and pile foundation. The effects of pier-pile-soil interaction on displacement response of the soil surrounding the pile foundation are significant. The effected range is about 1.5 times width of pile foundation. The internal force responses of piles indicate that the bending moments and shear forces of pile head and upper portion of pile shaft are larger relatively. The shear force of outer piles is marked larger than that of center piles. In addition, based on the principle of intensity damage, the dynamic reliabilities of the pile foundation are analyzed under four different yield shear force levels.

Aimed at the ill-conditioned problem of Biot’s consolidation finite element method (BCFEM), both orthogonal test and dimensional analysis method are used to study the ill-conditioning regularity and its influencing factors. The influencing factors such as the average size of finite element, the length of timestep, the compressibility of soil and the permeability of soil are taken into account. Two groups of independent similarity criteria are proposed, on the basis of which, two novel dimensionless variables are obtained to analyze the variation of the condition number of BCFEM coefficient matrix. Through the parametric study of an illustrative case, the results show that the average size of finite element, the length of timestep, the compressibility of soil and the permeability of soil are in the order of priority of sensitivity. The smaller the averaged size of finite element, the worse the ill-conditioning situation of BCFEM. With the increase of the presented dimensionless variables, the ill-conditioning number shows a tendency to increasing, etc. The conclusions are helpful to study the ill-conditioned problem of BCFEM.

The bearing characteristics of dry jet mixing pile composite ground are investigated. The stresses on pile and soil and their variation under flexible load have been measured; and pile-soil stress ratio of composite ground with DJM pile under flexible load and its variation with the load have been studied. The investigation indicates that the static loading test curves of composite ground are of gradually varied shape; it is feasible that load corresponding to relative settlement ratio s/b =0.01 is taken as basic bearing capacity value of composite ground according to relative settlement method. Because of running compensation effect of cushion, pile-soil stress ratio n changes comparatively gentle with load. Pile-soil stress ratio n changes about 1.73-6.83; its average value is 3.20.

A damage model that can reflect characteristics of impact load and anisotropic damage evolution has been embedded into FEM software; and the damage characteristics of cement mortar block with prefab cracks under blasting have been simulated. The results of research indicate that a serious damage zone exists nearby blasting hole. The range of the serious damage zone can be determined by the simulating results. The simulating results are similar to the one from test. So, the method proposed can provide theoretical evidences for stability analysis of rock that has been disturbed by blast loading in geotechnical engineering.

The unified technical standards on the conservation engineering of historic buildings and sites are very limited in the world; the investigation combined with geomechanics and conservation methods research is becoming more and more important in the field of ancient buildings conservation, especially to the protection engineering of landmarks located on the slopes. This paper describes the damage analysis process and conservation approaches selection to the West Scriptures Printing Hall of Potala Palace in Tibet. The structural stability and possible damage under gravity and earthquake load is analyzed. Rock engineering techniques and structural analysis method are applied to explore the bedrock mass properties and structural characteristics. The main three factors which influences the stability of the West Scriptures Printing Hall are achieved, such as heterogeneous property of bedrock mass, stiffness difference of the structure and heterogeneous distribution of structural load. Futhermore, the ground stress characteristics in the bedrock are analyzed and the mechanisms of deformation and foundation subsidence under comprehensive effects of the main three factors are explored by numerical simulation , which can provide a lot of useful experiences on the conservation engineering of landmarks located on the slopes.

The interface between structure and coarse grained soil was found to exhibit remarkable coupling of shear stress-strain relationship in both the directions due to three-dimensional shear application based on test results. The magnitude of principal shear strain is only dependent on the magnitude of principal shear stress. A three-dimensional constitutive model and its numerical scheme were then developed based on the elastoplasticity damage theory, which was programmed and used to predict the response of soil-structure interface. The model and its numerical scheme were confirmed to reasonably characterize main behaviors including the coupling of shear stress-strain relations of the interface between structure and coarse grained soil, which may have much effect on the response of interface.

Based on Walsh equation and elastic equation of spherical holes, the approximate and accurate relationship between porosity and bulk modulus of porous medium are acquired. The approximate equation is not suit for big porosity very well. For big porosity the accurate equation should be used. Experiments show that the accurate equation can express the relationship of porosity and bulk modulus of porous medium well.

Effects of grouting on the bearing behavior of bored pile are analyzed with the finite element method in accordance with the test results of large diameter over length piles. According to the back-analysis results, shaft friction, modulus of deformation of consolidation body in the base and modulus of soils are improved in different degrees ,modulus of deformation of soils along shafts were improved 33 %-67 %; the average friction resistances are improved 30 %-40 %; which are satisfactory relatively.

According to the failure features of concrete lining under seepage load，a three-dimensional numerical coupling analysis of seepage field and stress field is made on the fracture regulation of the high pressure conduit lining. Based on cracking characters of concrete lining, the computation formulae of crack width for concrete lining under seepage load are given. According to the bearing capacities of the concrete lining at the instant of cracking, the seepage load can be divided into two parts during computation. The preceding part of the load, smaller than that critical load, can be applied to the concrete lining structure once; and the latter part which is larger than the critical value adopts gradient iterative method. By this way, the rock slope stability taking into account seepage interaction effects can be analyzed preferably. Through computing practical engineering, the infection of seepage induced by high pressure water inside conduit is demonstrated. An efficient computation method is provided for the design of underground conduit with high internal water pressure.

As is known to all that the freezing-heaving mechanism of tunnel surrounding rock is a common problem of the tunnel in the cold region. Firstly, the several existent theories about freezing-heaving mechanism are introduced and evaluated. Secondly, the freezing experiment of rock sample is mode; after saturated, the rock samples from a cold region in West China. The CT scanning technology is applied to measure the meso-structure change of rock sample and the water transfer within the sample. The shrinkage phenomenon in volume has been found after the rock sample frozen. Finally, the freezing-heaving mechanism of tunnel surrounding rock is studied, which is believable to be helpful to the tunnel in the cold region.

Based on the concept of bounding surface, a bounding surface plastic model for sand-structure interface is developed; it can describe the hysteretic characteristics of a shear stress and strain curve. Initial relative density and normal pressure are included in the model; and a damage factor is also introduced in the elastic modulus in order to characterize the hardening interface response under cyclic loading gradually. The predicted response and test data are compared; and the proposed model is proved to be reasonable and credible.

In light of the different variances of friction against shearing and cohesion, a new method based on partial coefficient is proposed to apply to gravity dam stability analysis. And the corresponding stability check formula is derived. This method is based on reliability idea, and the dam final stability coefficient dam of is defined by the strength reserve coefficient or over loading coefficient at limit equilibrium state. From gradual failure progress and failure mechanism of dam foundation, further discussion is performed that several key problems should be given attention and how to define safety coefficient criterion for gravity dam stability analysis against sliding in foundation with nonlinear FEM. The research results show that stress distribution on foundation surface for gravity dams and deformation characteristic of foundation rock had an important influence on safety coefficient. The computation results of actual projects show that, compared with the conventional rigid limited balance method, safety coefficient criterion of partial coefficient FEM tends to be on the low side.

The mechanical behaviors of the jointed rock masses during tunneling and lining are simulated using discontinuous deformation analysis (DDA). Two improvements for tunneling and lining are developed and implemented into the original DDA program and the process of the tunneling and lining are simulated using the advanced program. The influence of the joint direction on the deformation and the stresses distribution of the jointed rock masses are investigated during tunneling and lining. The effect of the excavation sequence on the stability of the rock around the tunnel is also simulated. From this study, it is found that the joint direction has primary impact on the deformation and the stress distribution. The excavation sequence has also impact on the deformation and the stability of rock masses. These results suggest that the advanced DDA can be applied to simulate the tunneling and lining behaviors of the complicated discon-tinuous rock masses.

The hydraulic parameters of gravelly soil are difficult to determine due to its high gravel content and large grain size. The field permeability tests of gravelly soils layer of the slidebody of Xietan landslide have been carried out by double ring; and the test results are analyzed by empirical formulas, considering the soil porosity, grain-size distribution etc. Then, the soil-water characteristic curve (SWCC) is tested by the method of tensiometer-moisture content and fitted by Fredlund model. And finally, the unsaturated permeability coefficient of gravelly soil is calculated by empirical formulas based on its SWCC and saturated permeability coefficient. The test data demonstrate that, the saturated permeability coefficient of gravelly soil layer is quite good with permeability coefficient varied between 1.78×10-2cm/s to 3.2×10-2 cm/s; smaller fine grain content, bigger effective grain size and controlling grain size will lead to larger permeability coefficient. Through these works, the unsaturated hydraulic parameters are determined for the unsaturated seepage analysis of Xietan landslide; and the technique can be used as reference for similar soils.

In expressway widening construction, differential consolidation settlement and mechanical properties between new and old foundations especially soft foundation will cause severe pavement crack; and controlling differential settlement to avoid pavement crack in joint section becomes the key technique in embankment widening project. Focusing on soft foundation treated respectively with thin-wall pipe piles and DJM piles, selecting sections with typical geotechnical condition and comparatively high embankment, by burying settlement plate, a dynamic monitoring has been performed for obtaining the settlement of foundation during embankment widening. The results indicate that(a)the accumulated and differential settlement are both small and the settlement rate is smaller than the controlling standard, which provides basis for differential settlement accessing and (b)the two disposal methods, thin-wall pipe piles and DJM piles, are respectively accommodated for soft foundation with large embedded depth and layer thickness and with small embedded depth and layer thickness; and the treated new and old foundations is turned into fine compound foundation; so, a satisfied result is obtained for foundation widening.

According to the mechanics of anchorage, the importance of researching the interaction between anchorage and ground is discussed. Based on theoretical analysis, the process of the relative-slip between soil and anchorage is composed of three phases; and the mechanism of each phase is explained respectively. And then, the distribution of shear stress in each phase and the distribution of tangential displacement of the interface are presented. After that, a model test of anchorage is carried out with the geometrical scale of 1:100. By analyzing the test results, the propositions in theoretical analysis are performed.

Roof collapse accidents, potentially in the association with lithology and occurrence of roof terrane etc., are termed to be one of the most severe calamities in the coal mine exploitation activities. The thickness of weak terrain as one of the most critical elements in roof collapse accidents is discussed in detail here. After carrying out the mechanics analysis for roof failure in coal mines employing rock failure process analysis system (RFPA2D) developed by Northeast University, this paper conducts subsequently the numerical calculation for varying roof failure instances under different weak terrain thicknesses and probes into the impact of weak terrain thicknesses on laneway stability, concluding in the situation of different weak terrain thickness both failure processes after exploiting laneways and shapes formed ultimately by roof collapse. Roof supporting methods for weak terrain in different thicknesses are also listed finally. It is believed that conclusions from this paper are of significant reference not only to construction on site but also for experiments.

In research of spatial distribution characters of landslide，according to the data of landslide in Chinchina of Columbia，the fractal characters of spatial distribution character of landslide have been researched based on GIS. The results show that area of landslide with gradient, lithology and landuse is in second-order cumulative total fractal distribution. Their fractal dimensions have been carried out after calculation, and physical significance of fractal dimension is explored so as to provide a new way for integrated evaluation on landslide stability.

The dynamic movement of the working face abutment pressure during the coal mining is simulated with the FLAC-3D simulating software. And the curve about the relation between the abutment pressure concentrated coefficient and working face advanced distance is fitted according the simulating results. Contrasting simulation results, the relationships between abutment pressure concentrated coefficient and the distance which distant S meter from the rip with factors such as working face advanced distance, face length, coal seam thickness and buried depth are obtained. Then gained the attribution laws of abutment pressure. Those laws can offer gist for roadway maintenance, coal and gas outburst and caving evaluation of top coal.

According to the one-dimensional Terzaghi’s consolidation theory, the relationship between the consolidation velocity and time is deduced, which could be used to propose a new method for evaluating the analytical solution of the coefficient of consolidation. This new method avoids the disadvantages of the graphical methods, and eliminates the influences of the initial settlement and the secondary consolidation. Some statistic software can be used to deal with the original data based on the least square principle. Compared with the other traditional methods by two practical examples, the new method can determine the coefficient of consolidation in practice, with good accuracy, reliability and convenience. Especially, it does not need the test data from the initial and the secondary consolidation; so it can accelerate the course of the consolidation test.

Ground loss is inevitably produced during pipe jacking construction; and ground settlement is brought consequently. Based on the previous study, general empirical formula to calculate settlement at any point is advanced. Assuming soil is not drained, the Sagaseta formula is modified by considering the Poisson’s ratio of soil and adopting oval-shaped ground deformation pattern around tunnel section. It is shown in analytical calculation that, for the spot far from the rear of excavation face, the calculation results using the modified Sagaseta formula is quite accordant with that of the Peck formula and the Loganathan formula. The calculated deformation rule using the modified Sagaseta formula is accordant with that of the accumulated probability curves. Both ground settlement above the excavation face are half of the maximal ground settlement; but the accumulated probability curves own smaller effecting range and quicker convergence speed. These calculation methods also apply to shield construction.

A series of consolidated un-drained triaxial tests with equal consolidation ratio and equal shear are done for undisturbed loess Q3 samples from Longxi region of Gan-Su province. The total stress method is used in study. The test results indicate that the stress path has certain influence on the loess shear strength when loess has some different properties in different directions. The destroy points of the stress path tests, together with those of regular triaxial tests, distribute in a strip of area.

Non-pillar continuous mining is high-efficient mining technology. It is a general tendency to carry out this mining technology in underground mine. Dipping at high angle and thickness ore-body with upward horizontal slicing and filling non-pillar continuous mining was briefly introduced as an example of continuous mining methode in a Pb-Zn mine. The elastoplastic three-dimensional finite element analysis technique was employed to simulate the practical excavation and backfilling mining activities. Stope stability status with different height of slice , the numbers of pre-slicing and the exposed areas was analyzed so as to provide the optimum stoping structural parameters for mine operation.

A kind of new composite soil nailing with reinforced cemented-soil wall is described and applied in a foundation excavation project in wuhan. A field investigation with extensive instrumentation and data collection is carried out, then the behaviors of the new composite soil nailing are further investigated based on the measurement. The main results are：(1) the defection is large at the top and little at the bottom; (2) cemented soil and reinforcing bar can work together at some level of stress; (3) the reinforced cemented-soil wall plays an important role during construction; (4) the behaviors of this supporting system include retaining-wall effect, reinforcing effect and anchor effect.

Pile-net composite foundations can be used to minimize the vertical and horizontal displacements of embankments on soft clay foundations. The behaviors of clay foundations stabilized by dry jet mixing piles combined with geogrid are studied，including settlement, excess pore water pressures and soil pressures. According to testing results, changes of pressures on and below geogrids , stress ratio of pile to soil, dissipation of excess pore water pressure and the relation of settlement and soil pressure are analyzed. .From that, it can be concluded that (1) the excess pore water dissipates slowly, but its value is not larger than the above loading; (2)geogrid can improve the average result of soil pressures and can make the stress ratio of pile to soil large, and at the same time ,based on distribution of soil pressure of each cross section ,the viewpoint of arching effect is put forward; and (3) settlement is generated mainly by compress of the underlying clay and piercing deformation and self-deformation of dry jet mixing pile; the testing data provide useful information for theoretical analysis and designing.

The permeability test of coal in the complete stress-strain process is carried on the MTS815 Servo-controlled Rock Mechanical Test System. Test results indicate that the permeability rate curve and the complete stress-strain curve of coal almost have the same variation trend. But the permeability rate-strain curve is relatively “hysteretic” which indicates that the close relativity between the evolvement of damage and the development of permeability rate and the permeability developing needs a time. The micro-structure and micro-composition of coal are more complicated and different than other sedimentary rocks; so the permeability of different kinds of coal is much different. Moreover, the micro-porosity and micro-fracture of coal are more developed, so the influence of available confining pressure on penetrability of coal is more obviously.

Stress analysis of flathead shaped slope in highway excavated slope is conducted with advancing exterminating methods of shear sliding section at the toe of slope, and pointing out that in the range of shear sliding section, depressed shear strength of geotechincal mass will result in knock-down of slope stability. Examples show that with consideration of differences of mechanical properties in shear sliding section, maximum dangerous slide face by method of limit equilibrium will degenerate into vice dangerous slide face; and stepping slope face will dissipate stress concentration at the toe of slope.

The stress-strain curves of two kinds of reinforced expansive soil with different water contents around optimal value are obtained by triaxial shear test on reinforced soils. The strength of the sample with the same water contents gets stronger with the increase of reinforced layers and confinement pressure; the strength of the sample under the same confinement pressure and reinforced layers increases obviously by reducing slightly its water contents; and the result that the strength of reinforced expansive soil is sensitive to water contents is gained by analyzing the test curves.

The accidented pavements could bring displacement disturbance to the vehicles moving on them; and the irregular disturbance caused the vibration of the vehicle, which made the vehicles produce additional dynamic loads on pavement during vehicles running. The vehicle dynamic loads are the main reason that caused the pavement failure. The correlative studies concentrated on the dynamic load of single vehicle on pavement, while the unstable traffic flow loads worked on pavement actually. Aimed at the engineering problem, the car-following model was used to simulate the velocities and relative distances of every vehicle on pavement. PSD (Power Spectral Density) was used to describe the stochastic characteristic of pavement roughness. Then, the simulation model of the quarter vehicle vibration system was built using Simulink. The dynamic response analysis of cement concrete pavement under traffic flow loads was processed; and some conclusions were drawn, that could provide references for the structural design of pavement and vehicle, and the analysis of dynamic interaction between vehicles and pavements.

Land subsidence has caused serious and costly damage to the Taiyuan City. Some previous researches attributed the problem to excessive withdraw of groundwater. However, the explanation was challenged by the noncoincidence of the spatial patterns between land subsidence and groundwater exploitation. The monitoring data in the period of 1956-2000 show that the land subsidence spatially coincides with the groundwater depression on the whole, but deviates locally. In the present study, spatial heterogeneity of medium is used to explain the phenomena. The following factors are taken into account: patterns of accumulated clay soil thickness, configurations of clay soils and coarse soils, and mechanical properties of soils in different sub-zones and depths. It is found that: (1) the land subsidence centers deviate from the corresponding groundwater depression centers to the sides with thicker accumulated clay soils; (2) in the same intensity of groundwater withdraw, the subsidence volume is usually greater where clay interbeds are more and the individual interbed is thinner; and (3) the land subsidence is correlated closely with the mechanical properties of soils.

Settlement analysis of municipal solid waste (MSW) is one of the hot points and key points in the construction of landfill and in the field of geoenvironmental subjects. The control of differential settlement of MSW is the basis of design of middle liner system in the vertical expansion of existing landfill. It is very important to calculate and analyze the differential settlement of MSW correctly in order to ensure the success of vertical expansion of existing landfill. Aiming to the MSW differential settlement in the landfill of vertical expansion, calculation procedure is introduced firstly; and related application analysis is conducted with an engineering case. Finally, corresponding solving plans to control the differential settlement are presented from viewpoint of engineering technology.

In course of the approaching excavation of underground works, the construction of new structure will change the mechanics case of existing structure and brings some bad influence. At the same time, the mechanical mode of newly-built structure is not the same as that single cavern is excavated in the half-unbounded space. Its original stress field is disturbed by former time and time again, and once more by excavating of later. A project is taken into account in this paper. By the three-dimensional elastoplastic finite element analysis, results show whether we should reinforce the old tunnel or not, it gives the suggestion, as well as whether the shield driving influences the orbit pitch of the old tunnel. It also simulates three pressure on the shield machine and how to influence the distortion and the principal stress. Finally, it makes the conclusion that may instruct the design and the construction of the project.

The calculation of displacements and internal forces of the cantilever-retaining pile for foundation pit using biparameter method of foundation resistance is discussed. That is on the assumption that the foundation resistant coefficients varies nonlinearly with the depth according to biparameter theory; the strata are modeled by elastic foundation link elements and the soil-retaining piles are modeled by elastic beam elements. Based on the real measured data, the numerical simulation back-analysis of the cantilever- retaining pile for foundation pit indicates that the proper parameters of foundation resistance for practical design could be obtained through trial and adjustment. And the method is applied to practical analysis and design of the cantilever-retaining pile in Fuzhou. The result is satisfactory, so it could be referred by the design and the calculation of the cantilever-retaining piles for foundation pits.

Because of different test fundamentals, the bases of judging soil damage with different test methods are also dissimilar; and some test data must be amended with probability statistics; and that cause a rather large otherness among value of subgrade bearing capacity with different test methods and bring a large inconvenience to scientific effort and engineering practice. Since there has a internal relation between the data gathered by different tests and bearing capacity, contraposing different lithologic soil body; regression analysis is used to establish dependency relation between ratio penetration resistance and subgrade bearing capacity, numerical standard penetration and subgrade bearing capacity, interior geotechnic parameters and subgrade bearing capacity; so as to against the otherness in different methods; and that can provide fast and accurate characteristic value of subgrade bearing capacity for expressway surveying and design in the Yellow River delta region.

The strength formation features of different area soft soils consolidated with cement are studied through laboratory tests; and the mechanical indexes of cement consolidated soil are determined by means of direct shear test and unconfined compression test. It is found that there is great difference in the mechanical properties of different area soft soils after the stabilization with cement, which is explained from the aspects of granular metric composition, content of organic matter of all samples and the microscope structural characters of stabilized soils. Results show that the granular metric composition and the content of organic matter in soil have great influence on consolidation effect. The more clay particles and the higher organic content in soil, the more difficult is it to enhance the strength of cement consolidated soil. So it can be for reference to select reasonable additional measurements in projects of using cement to stabilize soft soil with different properties.