By extending the 2D explicit limit equilibrium solution based on normal stresses over the slip surface of the 3D slope, a simple and convenient method of 3D slope stability analysis is presented; it is applicable to general-shaped 3D slip surfaces. Firstly, the normal stress distribution over the 3D slip surface is initially assumed, it is then modified to satisfy all the three force equilibrium conditions. A quadratic equation is derived in terms of safety factor, it finally yields the explicit solution to the 3D safety factor. The proposed method has overcome some insurmountable difficulties encountered in the current methods of columns; and free of consideration of inter-column forces, satisfying the major equilibrium conditions and features; simple and practical computation process. Example studies show that the proposed explicit solution gives the 3D safety factor of a wedge identical to the analytical solution, agrees well with the rigorous limit equilibrium solutions of symmetrical slope. The method has been applied to the preliminary 3D stability analysis of a dam abutment; and the computation results offer a guidance for design of stabilization.

It is a basic problem that obtainment of the local stress field from the large stress field. The usual methods consist of two steps including interpolation of stress field or boundary conditions and calculation of the local stress field once again. But the previous methods are too complex, high calculation cost or special for a class of problems to being applied. From the engineering angle of view, it is unessential for the high degree of accuracy as to stress field interpolation affected by the complicated geology construction. So, the improved IDW (inverse distance to a power) method which considers the volume effect is presented aiming to the above problems. Based on this method, the obtainment methods of local stress field, in which two kinds of boundary conditions are proposed, are presented for solving the corresponding plane problems, 3-D ground problems and 3-D underground problems. Their rationalities are verified through the settlement of several cases. Finally, the methods are applied to the stability analysis of high rock slope in Nuozhadu Hydropower Project. The results indicate that the improved IDW method is simple and practical; the corresponding solving methods for local stress field are efficient and of satisfied accuracy.

The analyses of soil slope in arc slipping need to search three parameters of radius and coordinates of the arc center. By moving the slipping arc horizontally, it is found that the slipping arc must pass through the slope foot or the horizontal coordinate of its center is determined by the radius. It is proved that the slipping arc of vertical slope must pass through the slope foot, where the slipping angle is greater than the internal friction angle. For pure cohesion soil or no friction soil, when the slope angle is greater than , the slipping arc passes through the slope foot; otherwise its center on the perpendicular line through the middle point of the slope face and the critical height is for the arc with infinite radius and slipping angle ? 66.78? at the slope bottom. Based on the numerical calculation, the slipping arcs do not pass through the slope foot when the slope angles are less than 40?, 34? and 22? for internal friction coefficient 0.05, 0.1 and 0.2 respectively; but their critical heights are only 2 % less than the slipping arcs through slope foot. When internal friction coefficient is greater than 0.3, the slipping arcs pass through the slope foot. So only the arcs passing through slope foot are needed to calculate for the critical height of soil slope.

In order to investigate the relationship among stress, strain and strength of soil under unsaturated moistening, water content is introduced into the hardening parameter of Tsinghua model to develop the Tsinghua elastoplastic model of unsaturated soil. On the basis of moistening tests by means of mixing ice crumblings into dry soil, it is shown in the test results that this model is capable to predict the relationship among stress, deformation and the strength of unsaturated soil under different water contents. The results of model calculations well agree with the test results of soil moistened from the air-dry state to other unsaturated states corresponding to various water contents. With water content directly introduced into the elastoplastic model instead of the complicated matrix suction, it might be showing a handy and explicit way to the engineering application of unsaturated soil constitutive models.

In order to simplify the construction procedure and shorten the construction period, the concrete crushing-type side wall(CSA) technology is widely adopted during constructing many concrete face rockfill dams(CFRD), in which the CSA replaces the traditional cushion as the contact interface with concrete slab. The construction specificity of CSA decides that the larger difference will exist between the contact relation between CSA and concrete slab and the one between cushion and concrete slab. Although recent construction technology has greater development than before, concrete slabs’ cracks of a few CFRD still occur seriously. Distributing rule of cracks for CFRD with CSA is not same with ones which adopt traditional cushion. The cracking of concrete slab has great relation with its stress state during construction period. At present the whole computation method of concrete slab stress analysis exists more simplification assume, which results in pour stress accuracy of concrete slab from computation results. Submodeling method is presented to compute the stress and deformation of concrete face slab considering CFRD constructed by stages. A contact friction element with no thickness based on coulomb friction model is applied to simulate the special boundary between CSA and concrete face slab. The actual project analysis result shows that the temperature decrease and the intense constrain with not flattening of upstream slope at some altitude bring about cracking of concrete slab.

Soft rock is a familiar rock mass in rock engineering. One main character of soft rock is swelling and collapsing after clay mine absorbing water. By deeply researching the granularity fractal characters variation regularity of the slaking material in different slaking stages, a mathematical model to simulate the slaking process of soft rock is established based on fractal concept. Simulation results show that the same developing trend as the experiments results which proves the slaking process of soft rock is typical fractal. According to the results, parameters of the mathematical model can be back analyzed by few experiments data; and the critical value of fractal dimension of soft rock can be calculated. Furthermore the mathematical model can be used to forecast the fractal dimension of swell and collapse in long term.

Based on the strength reduction method of finite element method, the elastoplastic material nonlinearity and large deformation geometrical nonlinearity of the slope are studied; and three dimensional deformation features of the slope are also considered. In the finite element analysis, the realistic elastoplastic model of Mohr-Coulomb is adopted; and the method for describing the large deformation characteristic of the soil is updated Lagrangian method. Through analyzing a homogeneous slope, it’s concluded that there exists the same rule among the results of the finite elements and simplified Bishop method. The rule is that the factor of safety will become large if the cohesion and the internal friction angle become large, and it will become small with the increase of unit weight. However, the results of the finite element methods are always larger than the corresponding value of the simplified Bishop method, which means that the result of simplified Bishop method is inclined to conservative. The decreasing order of the four kinds of results of safety factor is Fs (three dimensional small deformation), Fs (two dimensional large deformation), Fs (two dimensional small deformation) and Fs (simply Bishop Method); among them the first two methods are the best one and their values are very close each other.

Based on general Biot’s dynamic consolidation theory, a simple analytical model for simulating random wave-induced seabed response and liquefaction is established and solved together with stable and effective algorithm. The influence of random wave loading is investigated by comparing with the corresponding linear regular wave results with similar representative parameters. The results of comparison show that the distributions of amplitudes of pore wave pressure and effective stresses along depth in seabed are similar by using two different wave theories, but the dynamic response of seabed under random wave loading shows clear irregularity, and these amplitudes are greater than those under linear regular wave loading on the same quantity level. Compared with the liquefaction depth induced by linear regular wave loading, the result computed with random wave theory is much deeper. Therefore, the stochastic feature of random wave loading has to be duly taken into account in evaluation of safety and stability of various marine structures and offshore facilities.

The present calculating methods of secondary consolidation of soils do not consider the influence of structure, but most of the natural sediment soils behave the structural characteristics. The tests of marine clay performed by the authors show that secondary consolidation of structural clay relates to load not only in overconsolidation state but also in the process of structure destroying. The secondary consolidation coefficient rapidly increases with consolidation pressure when consolidation pressure is lower than the preconsolidation pressure, and slowly increases when pressure is between the preconsolidation pressure and the structure full yield stress. If the consolidation pressure is higher than the structure full yield stress, the secondary consolidation coefficient would not vary with consolidation pressure. Whether the secondary consolidation coefficient is varied with load should not be judged by preconsolidation pressure, but it should be the structure full yield stress. For marine clay, the varying process of secondary consolidation coefficient can be considered as three phases, i.e. overconsolidation, structure destroy and normal consolidation. A new calculating method is developed, which can reflect the structure behavior of soils.

In order to analyze the tension in geomembrane placed in landfill slope owing to the weight of municipal solid waste on the sealing liners, analytical solution of geomembrane tension based on equilibrium equation of geomembrane is gained with a strain-softening model of geomembrane-clay interface taken into account. In contrast to the conventional approach, this method can analyze three different stress states of the geomembrane-clay interface: elastic state, softening state and residual state; so it would be more reasonable for analyzing geomembrane tension. Parametric studies show that if the strength of loss in softening phase and the difference between residual displacement and peak displacement is small; the peak shear strength of the geomembrane-clay interface has a small effect on the geomembrane tension; and the maximal tension of the geomembrane mainly depend on its residual shear strength. Contrarily, if the softening characteristic of the geomembrane-clay interface is obvious; the influence of the peak strength and residual displacement is more notable. In addition, the height of the waste or the cover clay on the liners, the angle of slope and the length of geomembrane also have heavily effects on its tension.

Tunnels in saturated sandy foundation may subject to severe damage due to earthquake-induced liquefaction. Dynamic centrifuge tests on seismic response of metro tunnel in liquefiable soil are conducted. The seismic response of saturated loose sandy deposit, the uplift and deformation performance of metro tunnel in liquefiable soil are investigated. The effectiveness of cut-off walls in reducing structure uplift is also validated. Test results show that the liquefaction induced inner force in tunnel segments and its uplift are mainly influenced by excess pore pressure and earth pressure increment during earthquake. The cut-off walls prevent liquefied soil from moving toward the bottom of the tunnel, and then the uplift of the tunnel is reduced effectively.

The stress ratio between pile and soil is a key parameter for the design and calculation of composite foundations. Based on single pile composite foundation static load tests of Yan-Tong Expressway, the influences of cushion modulus and thickness, pile modulus, pile length, base stiffness etc. on the stress ratio of pile-soil are analyzed by using the finite element analysis. The results show that the model built is reasonable. The stress ratio of pile-soil increases with the cushion modulus increase or thickness decrease, and with the increases of pile modulus, pile length, base stiffness.

Based on the mesh regeneration and stress recovery of modified REP technique, a three dimensional large deformation finite element (FE) approach is presented to study the interaction between the cohesive soil and square plate anchors subjected to the pulling-up force. Different from traditional small-strain FE methods, large deformation analyses can simulate anchors’ pulling out process completely. If the soil beneath the anchor is always attached to the anchor base, the uplift capacities of square anchors are found to be very close to that of circular anchors. Once an anchor in the weightless soil is pulled up, the anchor base separates with soil immediately. In such case, large deformation analyses show the breakout capacity factor of square anchors is slightly lower than circular anchors. The breakout factors from large deformation analyses agree well with model test data. Both the small strain FE and lower bound theorem neglect the effect of anchor’s large displacement on the uplift resistance, tending to overestimate the capacity of deep anchors. A simplified method is developed to estimate the uplift capacity of square anchors for industrial applications.

Tailings pond’s accidences can bring in destroy on geological environment, natural environment and ecological environment. So an environment assessment index system of tailings pond is set up, and using fuzzy analytical hierarchy apprehensive model to appraise impacts of tailings pond on environment. In this model, the judgment matrix is constructed with fuzzy data so as to show the fuzziness and uncertainty of subjective judgment. So the influence of certain experts biased scoring might be reduced moderately. And multi-factor weighted model is adopted to calculate the last results. According to assessment standard environmental impact degree gained is slight influence.

The shaft load transfer factor is calculated through the shear displacement method. Based on linear load transfer function to pile-base soil, using the elastoplastic model, a set of analytical equations for the settlement of vertically loaded pile are obtained. The theoretical model considering the strength of soil varying along the depth and the slip between pile and soil will be more realistic in practice. It is extended to determine the interaction factor between two piles and application to the analysis of pile groups is also presented. The proposed approach overcomes the limitation of elastic theory. The validity of the proposed method is verified through the comparisons of finite element method and field tests for the settlements of single pile and pile groups. General good agreement lends confidence in the applicability of the proposed method to practical problems.

The pile-plank embankment is a kind of new-type of ballastless truck in high-speed railway. Based on the theorem of Bockingham ?, the dimensional analysis method is applied, and the dynamic model similitude constant of pile-plank embankment is determined. Dynamic characteristics of pile-plank embankment before and after soaking in water are analyzed by the large scale model test under dynamic loading. The test results indicate that dynamic stress of the soil decreases with the increase of vertical depth, and it is less affected by loading frequency. After the roadbed side-ascent soaking in water, at the same loading frequency, dynamic stress is slightly increased compared to embankment before soaking in water. Pile structure expands the depth of the dynamic response of roadbed and improves the stress of the roadbed soil. Bearing stratum at pile-bottom is greatly affected by dynamic loading; and it is one of the key of the dynamic design.

Firstly, based on the basic characteristic curves and revealed by the results of the soil dynamic tests, the rules of adjustable double-parabola constitutive curves of reverse unload after load process or reverse load after unload process in irregular load history are established, and function implementation and implement of A type and B type parabola are expounded for the characteristics of reverse load or unload curves sometimes change more flatly at first and then acutely. Secondly, by comparisons of 9 methods simulated results of soil test damping, the load and unload rules of double-parabola model accord with the test results, especially accord with the value of soil test damping, and they can be regarded as the simplification and practicality of generalized Masing rule. Because of the adjustment coefficient can be changed, the model has more powerful capability of simulation the shape of constitutive relationship curves. At last, using the borehole array records of Taiwan Lotung DHB field test, the nonlinear seismic response of DHB site are analyzed by equivalent linear method SHAKE91, LSSRLI-1, nonlinear method in time domain- DESRA-2, Pyke model, Non-Masing rule model ONE, implicit stress damping equivalent model, damping degradation coefficient model, Non-Masing rule model TWO and double-parabola constitutive model respectively. After compared all the synthesizing acceleration ground motions with the observation records, we found the PGA of double-parabola model are almost equal to the observation value, the comparative size relations of waveform, subsequence waveform are agree well with the records. As a result, the rationality of double-parabola constitutive model and the feasibility in practical engineering application are manifested.

The model of moment of force is introduced to the rock shearing failure; and the shearing failure process is analyzed. The moment model is used to explain the formation of low-angle structural-plane. When the rock has the shearing failure, the shear band has a certain width. On the shear band, shear stress and the support strength are not the even distribution. There is a process alignment procedure in cuts; and the stress concentrated in some part caused the existence of shearing moment. Along with increasing of , the supports strength and the shearing force all increase; the non-uniform distribution appears. The stress is concentrated partially; and the rock appears the partial failure. When the shearing moment is bigger than the support moment, the macroscopic shearing failure appears. Based on the destruction effect of groundwater, the change of interface with the variety of groundwater is analyzed. Along with the increasing of hydraulic pressure, the effective pressure and the contacted area rate of the structural surface and under the crag body changes slightly, the critical angle of the steady destruction reduces. So the rock block is easy to lose its steadily.

The full-scale field-test on uplift behavior of pedestal piles with small extend angle enlarged base and normal straight-shafted piles has been carried out. It indicates that the uplift bearing capacity of former increases 50 percent than that of the latter. In order to know the contribution of enlarged base of pedestal pile, the composition of uplift resistance of enlarged base is analyzed by FEM. And the development of each elementary composition along with the uplift is studied. The sensitivity analysis is done for different diameters, lengths, expansion angles of enlarge base and soil characteristics in which enlarged base embedded respectively. The uplift mechanism of enlarged base is known by contrasting the result computed at different values of same parameter. Finally, some advices for design of pedestal piles with enlarged base are proposed by combination of theoretical analysis and practice.

The hydraulic fracturing problems in fields of water conservancy and hydropower and mining are produced by natural hydraulic power. Its boundary conditions are different with them in artificial hydraulic fracturing applied to fields of petroleum and natural gas. The characteristics of hydraulic fracturing under natural power are generalized. The study level of hydraulic fracturing is divided into two based on study measure. The one is based on macroscopical, synthetical and statistical characteristics medium. The other is focused on a single fracture and a group of fracture with regular location. The characteristics of fracture flow are analyzed. In order to simplify the research, the hydraulic fracturing process of a single fracture can be divided two stage or two kinds. The different fracture flow models are proposed.

According to similarity principle of geomechanical model test, a new type cementitious geotechnical similar material called iron crystal sand is developed through a lot of material mechanics test. This similar material is evenly mixed with iron ore powder, blanc fix, quartz sand, gypsum powder，rosin and alcohol in certain proportion and pressed together. Iron ore powder, blanc fix and quartz sand are main materials, the solution of rosin alcohol is cementing agent, gypsum powder is regulator. Specimen mechanical tests show that the new-type similar material has many remarkable advantages as follows: high volume-weight, wide variable mechanical parameters, stable performance, low price, easy dryness, easy processing and without any toxicity and side effects. It can be used to simulate most of rockmass material from soft to hard ones. The new typed material has been used in 3D geomecanicl model test of bifurcation tunnel of Sanghai-Chendu-Xichang expressway and mechanical deformation properties of rockmass surrounding bifurcation tunnel have been effectively revealed under excavation state.

Based on nonlinear finite element method, numerical analysis is carried out to study the working behavior of composite soil-nailed wall(CSNW) in soft soil, including ground deformation and stress distribution in soil nails and leading piles. By comparing with simple soil nailed wall’s simulation, the function of the leading piles in CSNW is analyzed. It is shown that the leading piles in CSNW can significantly help decreasing the displacement of retained soil as well as change the distribution of soil deformation, reducing the tensile force in soil nails, and therefore, increasing the stability of the retained soil.

For the Three Gorges granite specimens, the conventional triaxial compression and the confining pressure reduction test under constant axial strain and stress are carried out. The lateral deformational characteristics of brittle rock under different stress paths or different loading control modes are studied; and it is found that the critical lateral strains are always in the range of ?0.004 5 and ?0.003 5. Based on the analysis of the complete stress-strain curves and the damage mechanism of the Three Gorges granite, it is put forward that the brittle rock mainly occurs lateral damage and exhibits the similar damage evolutionary rule under different stress paths and loading control modes; and the critical failure generally occurs at a damage variable level of 0.7 to 0.8. Finally, a damage model considering the unloading effect and a failure criterion in strain space are established, in which the lateral damage variable is seen as a critical variable.

Linear elastic model is common used to analayze retaining structure of deep foundation pit excavation, which is an approximate treatment in some aspects, such as material compose, material characteristics and so on. There will be some warp in the analysis with this model compared with practical situation. Based on the practical project of Qiutao Road Station excavation of Hangzhou Metro No.1. A nonlinear solid model is established to study the loading mechanism of secant piles. Compared with the measured results, it is shown that this method is vaild and it can be applied to the deep foundation pit design and construction.

It is important to research the mechanical behavior of the rock/rock and rock/concrete joints for the assessment of stability issues involving rock masses and engineering foundations. A finite element model of 3D rough surface unchanged in its width is established by employing ANSYS to simulate the direct shear test conducted by Bandis et al; then compared with the test results, some moderate well numerical results are acquired, which testified that it is feasible to apply ANSYS program to analyze the bi-body shear performance. In addition, several regular sawtooth interface computational models are used to examine the shear strength theoretical formula of Patton, consequently; it is proved again that using ANSYS to model the shear behavior is applicable. Furthermore, the evaluation of this paper focuses on the analysis of the shear stress-displacement curve, shear distribution on contact plane and dilatancy effect as well as cohesion effect.

Three test sections were designed to investigate their effectiveness in reinforcing railway subgrades by using concrete compacted base-enlarged piles and geogrids based on the construction practice in the k337?665 ? ?770 section of the Da-Cheng Railway. Track smoothness and associated dynamic responses such as the stress, dynamic deformation and acceleration rate under the locomotive load are recorded during the tests. Test results show that the dynamic response in test sections is below the relevant limits. Running speed has an different impact, and the rule of acceleration increase with run-up is most obvious. Smoothness and stabilizing of railway have remarkable influence on dynamic responses such as the stress, dynamic deformation and acceleration rate in railway line and subgrade structure.

To facilitate the practical application of nonlinear consolidation theory, some computation tables are prepared based on one-dimensional nonlinear consolidation theory, which can be used in consolidation analyses to take account of nonlinear properties of soft soil both in compressibility and in permeability, and actual distribution of dead weight pressure, as well as time-dependent loading. Numerical example is given to illustrate the application of the tables. The work provides technical tools for engineering computation and also references for theoretical research.

In engineering region, the equivalent linearization method is often used to the nonlinear seismic response analysis of soil layers in 1 D; but when the large peak acceleration time period is chosen as the computing input for taking account of load on site in large earthquake event, the method brings the remarkable “resonance” effect, which results to the mistakes in the evaluation to the surface response. For estimating the nonlinear seismic response more exactly, it is recommended to a true nonlinear method in time domain fitting curve and curve, and using it to 1D nonlinear seismic response analysis of soil layers on Xiangtang Array. In the study, the true nonlinear results of surface seismic response comparing with the results from the equivalent linearization method and actual records, the feasibility of the recommended method is proved. And the numerical studies show that the recommended method is more reasonable than the equivalent linearization method in large earthquake cases.

The dynamic displacement response of continuously reinforced concrete pavement(CRCP), which has horizontal resistance at its bottom, resting on a viscoelastic foundation has been investigated when the system is subjected to a harmonic moving load. The vertical displacement expressions of CRCP are obtained by using the trigonometric series and the Fourier transform when hysteretic damping is considered. Numerical results are derived through the inverse fast Fourier transform method(IFFT) and used to analyze the influence of various parameters such as the load velocity, frequency, reinforced ratio, strip thickness and foundation parameters on the dynamic displacement responses. The results can be for reference in analysis of dynamic response and pavement evaluation of CRCP.

Based on an in-situ test of single diaphragm wall under head horizontal static loading in loess subgrade, the level loading distortion characteristics were analysed and studied, with the increase of head horizontal load, the variation rules along the depth of the different section bending moment, horizontal displacement of diaphragm wall and loess resistance etc. were obtained. The results indicate that the third segment of upside diaphragm wall is influenced distinctly by the head level loading; horizontal displacement and bending angle of diaphragm wall presented nonlinearly decreasing down the depth, and increased with the development of head loading; the maximum values of bending moment of diaphragm wall and loess resistance take place within a range of depth below the earth's surface, the position of maximum and zero values of bending moment and loess resistance transferred gradually down along with diaphragm wall that accompanied with the head level load increasing; and curves of loess resistance –horizontal displacement takes on the properties of hyperbola; the maximum shearing force values of diaphragm wall occured on the surface, and shearing force varied nonlinearly down with the diaphragm wall.

The performance of a reinforced and an unreinforced embankments on mountain slope foundation are studied with full-scale models. The models are surcharged until collapse under load on the embankments crest. This paper focuses on the test design and instrumentation of the embankments on mountain slope. During the experiments, the vertical forces distribution, displacements of slope, the form and position of the slip curve surface in the two embankments are also investigated. The test results show that the geogrid will improve the stability and the ultimate bearing capacity; and the lateral displacements of the reinforced embankment are smaller than that of the unreinforecd embankment. The test resalts are very useful for the expressway design and construction in the mountain region.

Laboratory tests on dynamic pore water pressure of silty soils are carried out in a new universal triaxial torsional shear apparatus of Hohai University. The influence of clay particle content and silt particle content on dynamic pore water pressure of disturbed silty soil is concluded. The mode of dynamic pore water pressure of silty soil can be expressed in a modified exponential function with two parameters a and b to simulate the severity of liquefaction after initial liquefaction. It is found that fines content has great effect on the dynamic pore water pressure of silt by the parameter b. The relationship between parameter b and silt particle content is linear, while the relationship between parameter b and clay particle content isn’t linear which reaches the maximum value when the clay content is 8 %. It is validated that modified dynamic pore water pressure mode has widely application by many tests data from both the author’s and others’.

Uniaxial and triaxial tests are performed to study the stress-strain characteristics of the stabilized silt by stabilizing agents. The stress-strain curves of uniaxial and unconsolidated-undrained triaxial tests are analyzed; and the influence of age, mixture ratio, and confining pressures on the shape of curves are discussed. Uniaxial stress-strain test results show that the latter part strength and deformation characteristics of silt change small and with the increase of stabilizer amount, the curve of uniaxial stress-strain changes significantly. Triaxial stress-strain test results show that destruction of strain and stress damage shows a partial positive growth trend with the increase of stabilizer amount. When the curve at high confining pressure it shows weak softening type, when at low confining pressure it shows softening type.

The function of complex variable and stress wave theory are employed to study the stress and vibration velocity distribution of arch with vertical wall lining(AVWL) induced by blasting vibration; then the critical failure vibration velocity of AVWL is gotten when the incidence angles of incident wave are different. Firstly, the AVWL is mapped into a circularity whose outside radius is bigger than 1 but inside radius is equal to 1, and then the dynamical response of the circularity is solved under the acting of harmony P wave. The result shows that the incidence angle of incident wave has large influence on failure vibration velocity of AVWL, when the incidence angle is 90?, 0?, 270?, the critical failure vibration velocity of lining is decrease by degrees.

Laboratory experiments were carried out to investigate the aggregation effect of lime dosage and age on two types of expansive soils treated with slaked lime. It was found that the treating effects are rather different for the expansive soils of different liquid-plastic limit. The treating effects on highly expansive soils are much greater than those on the weak expansive soils. The treating effects are mainly completed within the first 24 hour period. As such, the resting time period after the second mixing is suggested to be reduced in engineering practices, which is very beneficial for soil density and strength improvement.

As excavations may cause change of the boundary conditions and the additional loss of bearing capacity of footings due to unloading induced lateral soil movement. Selection of shear strength parameters used in bearing capacity analysis for existing buildings near excavations is different from the one of general bearing capacity near slope. Those questions are discussed and the shear strength available corresponds to the average between the fully softened and residual shear strength is suggested. According to the idea, relevant bearing capacity for existing buildings near excavations is evaluated; and the results are compared with the test data and the theoretical solutions of bearing capacity near slope. Though present method is appropriate, it should be clarified by test as a strategy in design.

ADINA software, which is developed by ADINA R&D inc., has become the most important nonlinear finite element analysis software after more than 20 years of commercial development. It is considered to be the forerunner of the nonlinear finite element development and has powerful advantage in solving the complex structure nonlinearity and fluid-structure interaction problems. However, it is impossible for any commercial FEM software to meet all customers requirements; for example, there is no Duncan-Chang constitutive model in ADINA commonly used in geotechnical engineering. Taking Duncan-Chang E-B constitutive model as an example, the methods of conducting secondary development of material constitutive model and the development process are described. Then the Subroutine Cuser3 is verified by simulating three conventional triaxial compression models. Results show that material constitutive model developed in ADINA has advantages of fast convergence, high precision and convenient preprocessing-postprocessing. Results also show that ADINA has powerful nonlinear solution ability and reliable simulating results.

The large ground displacement caused by seismic liquefaction is one of the main reasons which induce the failure of engineering structures. According to the typical three-layer foundation at sloping field, the process of the ground displacement due to liquefaction is analyzed by using FLAC 3D. The numerical simulation considers the main effecting factors, including the earthquake, topography, soil and groundwater characteristics. The results indicate that lateral displacements become larger when the gradients of the free face and ground surface increase. The lateral displacement of the site with variational gradients is larger than that of the site with single gradient. The surface lateral displacement, subsidence and upheaval become more serious when the ground maximal acceleration and earthquake time increase. The burying depth, thickness of the liquefaction layer and the ground water level affect the large ground displacement also. So, the reasonable ground improvement scheme should be considered according to the actual conditions.

This paper summarizes the development of experiments on the fluid dynamic characters of liquefied soil as well as recent numerical simulations based on computational fluid dynamics (CFD) about seismic liquefaction. The cubic interpolated pseudoparticle (CIP) numerical method, which is emphasized herein, is active at present and is available to simulate the flow state of liquefied soil with high accuracy. Compared with conventional solid mechanics, CFD has significant advantages in the following three areas on liquefaction analysis: (1) large deformation of soils; (2) parameters of liquefied soils; (3) deformation of structures in liquefied soils. In future research, the applications of CFD to the seismic liquefaction, should take into account soil behaviors in the status before liquefaction and dynamic pile-soil-structure interactions during liquefaction.

Considering uncertainty of parameter in slope stability analysis, an improved algorithm for self-organizing feature map(SOFM) neural network is presented to increase the convergence speed and capability, and a SOFM neural network model for evaluating the status of the slope stability is established based on the improved algorithm. Then, the SOFM neural network model is trained and checked with the collected slope analyzing examples, and compared with results obtained by the BP neural network. The results show that the SOFM neural network presents excellent network performance, high prediction accuracy; and it is an effective way to evaluate the stability of slopes.

through the triaxial CU tests of compacted silts under different water content by using an unsaturated GDS triaxial apparatus , the strength and yielding characteristics of the silts taken from Beijing-Kowloon-Railway subgrade are analyzed ,which provide an experimental basis for the establishment of soil mechanics model. Some conclusions can be made from the research as follows: (1) Higher strength and a tendency to work softening of stress and strain curves are shown of the samples compacted dry side of the optimum water content ,which also exhibit shearing dilatation initially and then shearing shrinkage; but for samples compacted wet side of the optimum water contents, lower strength and work harding trend are observed and the samples always exhibit shearing shrinkage characteristics. (2) The strength and yielding stress decrease with the water content increasing,which shows the softening effect of water on the soils behavior. (3) The yield loci at failure on q-p plane of different water contents exhibit linear relationship. The slopes of the critical state lines are independent of the water contents. (4) Cohesive increasing reflects the contribution of the water content to shear strength, and a power relation is shown between the cohesive and water content. (5) A formula taken water content as variable is deduced for calculating the shear strength, which shows good agreement with the testing data and can be used in practice.

The additional stresses induced by propulsion of double-o-tube(DOT) shield are calculated by means of the Mindlin’s equations in elasticity. The characteristics of additional stresses and the extent of soil disturbance of DOT shield construction are analyzed with compound Gauss-Legendre integral arithmetic. In the analysis, the excess earth pressure and the lateral friction between shield skin with surrounding soil are taken into account. The outcome makes clear that the soil disturbance of DOT shield has the regional characters, such as drag and extrusion above the sea-gulled segment and extrusion and friction lateral of the shield skin. The lateral friction has more effect on soil disturbance than the excess earth pressure. The conclusion can be as reference for the traversing construction nearby the underground pipeline and the building foundation for DOT shield.

The precise integration method is a high precision algorithm for structural dynamic response. The method is applied to foundation vibration response. In order to reduce storage requirement, matrix-vector multiplication that saves storage, and series solution are adopted; moreover, the precision of precise integration method isn’t affected. A corresponding program is developed for analysis of foundation vibration response. A building foundation of an important project is analyzed. The results are compared with the results of Nastran, a famous finite element analysis software; and correctness of above-mentioned methods and program is validated.

Aiming at the typical clay in Changchun, the Base-Seal stabilizer(BS-100 Model) from America is used to stabilize the clay. Then series of tests on the road performance of Base-Seal stabilized clay are conducted systematically. First, tests about the optimal proportion of stabilized soil are carried out. On this base, series of tests on the road performance indexes such as the unconfined compressive strength, indirect tensile strength, resilience modulus, frost stability, etc., are carried out in the condition of the optimal proportion. Base-Seal stabilized soil as base material has high early stage strength, high long stage strength and well frost stability has been put forward. And it is especially fit for Changchun and any other regions where the climate, sorts of soil similar to Changchun.

The hydrogeological structure of Xietan landslide is very complex; its slidebody, slipband and sliding-disturbed zone can be regarded as porous continuous medium, but its infiltrative bedrock is fractured. An equivalent continuum model is used to model fractured rock; and a finite element model of saturated-unsaturated seepage analysis of Xietan landslide is established. Then back-propagation neural network is used to substitute finite element seepage analysis; and saturated permeability coefficient of every stratum is optimized by genetic algorithm based on monitoring data during reservoir filling. The saturated permeability coefficient of slidebody by back analysis is 4.89×10-2 cm/s, which is consistent with field testing result(1.78?10?2 cm/s to 3.2×10?2 cm/s); the saturated permeability coefficient of slipband by back analysis is 4.66×10?5 cm/s, which is very larger than indoor testing result (2.74×10?7 cm/s to 5.73×10?7 cm/s). The scale effect of soil sample is reflected by this difference.

Infiltration flow in unsaturated soils often occars in engineering;and unsaturated hydraulic conductivity is one of important topics of unsaturated soils. Using the pressure-plate extractor, the soil-water characteristic curves under different compactive water contents and different compactive efforts are obtained. The corresponding saturated permeability coefficient is gotten by the variable water level method. Combined with the soil-water characteristic curves and saturated permeability coefficient, based of Van Genuchten model and Fredlund model, permeability of remoulded unsaturated clay under different compactive conditions is discussed in detail. The results show that the permeability coefficient decreases with the increase of compactive water content; and the its difference reduces with the increase of suction; and permeability coefficient can be assumed identical when the suction reaches 1 MPa. The permeability coefficient of samples compacted with standard Proctor compactive efforts and reduced Proctor compactive efforts are very similar. The value of is about 0.01 in saturated state, and increases with the suction increases. When the suction reaches 1 MPa, the value becomes 0.1 gradually.

The geosynthetic-reinforced cushion in pile-supported embankment works as a beam or plate, taking the characteristic of PCC pile composite foundation into account, therefore the reinforced cushion is considered to be an elastic thin sheet for calculation; and the formula of differential settlement between pile and soil has been drawn by using the thin sheet small deflection theory. On the basis of the compatible deformation between cushion and landfill, the methods of calculating the height of uniform settlement plate in landfill and stress ration between pile and soil have been got, but the compression of cushion material has been ignored. Finally, the comparison between calculated result and measured result shows that the formulas are acceptable. This method is also adaptable for other rigid pile-supported embankment.

A series of unconsolidated-undrained (UU) triaxial tests are performed in order to examine the effect of strain rate and confining pressure on strength and stress-strain behavior of reconstituted saturated clays. Strain rate is controlled to vary between 0.015 %/min and 3.75 %/min. It is found by comparing the experimental data that strength and stress-strain behavior are mainly affected by strain rate, however, they are almost independent on confining pressure. Undrained shear strength of the saturated clay increases with increase of strain rate; and the increase of 70 % of strength may be attained. An empirical correlation between strength and strain rate is proposed after a given normalization. Furthermore, the hyperbolic constitutive model of nonlinearity is recommended in order to take the effect of strain rate on the stress-strain relation into consideration; and the experimentally-based procedure for defining the parameters in the hyperbolic model is given. The model is verified through test data in the monotonic triaxial and torsional shear tests.

The design and construction of thaw settlement grouting during forced thaw in the metro connected aisle project are described. Temperatures in soil as well as ground settlement are monitored during the construction. Frost-heave and thaw-settlement may exist in freezing project. Superfluous frost-heave and thaw-settlement can cause disaster. Based on the actual engineering, the paper studies thaw settlement grouting during forced thaw in the metro. The method of thaw settlement grouting during divisional forced thaw eliminates the possibility of consolidation settlement. Good effects has been achieved in this project from the ground settlement measured in situ.

Based on the characteristics of geology and landform of the levees in the Dongting Lake region, a generalized model of vertical cutoff wall on multi-structure levee foundation has been established; then following the optimization concept and using the seepage FEM, a systematic study of the relationship between the vertical cutoff wall penetration in sand and gravel layer or the relative impermeable layer and the maximal seepage gradient inside levee is carried out. Then based on the FEM results, the comprehensive and objective estimation about the effect of anti-seepage of the two types is introduced. And a definition called critical optimization penetration is put forward for the first time. Finally, seepage FEM is applied to high pressure grouting cutoff wall project in Dadongkou Electric Drainage Project; the safe operation of real project shows that the analysis of this paper is right and practical.

Based on the engineering background of the Miaoya forked tunnel, the study of vibration characteristic of the ground at the large-span shallow part and blasting vibration reduction technology for large-span excavation has been done, according to the regression analysis for the results of monitoring on blasting vibration, the mathematical model for vertical propagation of blasting vibration has been established. Some conclusions are obtained by analyzing the vibration characteristic of the ground and the tunnel, the dominating vibration frequency at surface mass point mostly focuses on low frequency, the decreasing tendency of dominating vibration frequency at surface mass point is not obvious when distance increases, because some blasting earthquake waves are absorbed by the earth surface covered with soil of certain thickness; the high frequency is mostly absorbed by the concrete of the tunnel lining, so the blasting vibration impacting on the rock becomes weaker, the ground blasting vibration velocity of the excavation region is higher than that of the rock region; the ground blasting vibration velocity at the top of excavation region should be less than that of blasting security control in the large-span shallow tunnel.

A lot of landslides proved that: wreck of rock slope takes place along the joint, its slip surface always is the joint combination and is ladder shape. There are a lot of random joints in rock slope, finding out the slip surface whose shearing strength is minimum is a study direction of slope engineering. Based on investigating and statistics of joint, applying random network stimulation to reappearance space distribution of joints, and applying A* method to find out critical slip surface of rock slope; then separating slope above the critical slip surface slanting, combining with Sarma analysis method, come into being advanced rock slope stability analysis method-Sarma-A* method; and its rationality is validated by engineering instance.

The combined drainage and reinforcement cushion (CDRC) is a newly-developed proprietary technology which aims at coastal areas short of sand, is used for horizontal drainage and reinforcement in soft ground treatment and can replace horizontal dewatering sand cushion. The behavior of subgrade improved by CDRC has been analyzed by 2-D Biot consolidation plane strain finite element method. The result shows that the drainage capacity of CDRC can meet the requirement for drainage. Besides, it also shows that the technique can applied to lower foundation additional normal stress and excess pore water pressure, restrain the lateral deformation of foundation effectively, decrease vertical settlement and differential settlement of soft foundation and improve the foundation stability with remarkable effect compared with the traditional horizontal dewatering sand cushion.