We show the hysteretic nonlinear behavior of discrete memory, hysteresis loop and “X” shape tangent elastic moduli (Young’s modulus and Poisson’s ratio) in uniaxial cyclic loading experiments, and further clarify it using hysteretic quasi-static stress-strain equation of state in Preisach-Mayergoyz model (PM model) proposed by McCall and Guyer. Detailed curves of stress-axial strain, stress-radial strain, tangent modulus-axial strain and tangent Poisson’s ratio-axial strain are determined by space density and elastic property of hysteretic mesoscopic units (HMU) in PM model. In the equation of state, stress is proportional to the fraction of closed elastic units to total units, and the closed elastic units are related to applied pressure history, especially at the turn of pressure reversal. The response of strain is related to the stress path, and the model emphasizes the importance of stress history in determination of the elastic state of rock, hence the model can be used to simulate discrete memory. In this sense, hysteresis might be the cause of discrete memory in rock. By the simulation, we demonstrate the quantitative relationships between the parameters of PM model and elastic moduli of rock.

Tensile strength and deformation theory of granular materials are derived from the fractal characteristics of particle failure. The tensile strength formulas of granular materials are derived under the assumption that granular materials are D-dimension fractal bodies. The surface area and surface energy increase as the occurrence of particle failure; thus, one-dimensional deformation expression of granular materials is obtained from the conservation of energy.

Compacting properties, swelling-shrinkage behavior and mechanical behavior of compacted sample for weak expansive soils in Xiang-Jing Expressway of Hubei Province are investigated. It is discovered that the engineering behavior of weak expansive soils is controlled by the coupled action of water content and degree of compaction, while the swelling-shrinkage behavior is inherent property of weak expansive soils and its value depends on the initial water content and dry density; the optimum moisture content and maximum dry density of expansive soils depends on tamping effort, bigger tamping effort; bigger the maximum dry density, and smaller the optimum moisture content correspondingly; the variation of California bearing ratio(CBR)of the expansive soils with water content is similar to the compaction curve. However, the water content of soil corresponding the maximum CBR is higher than the optimum water content. In the construction of expansive soil embankment, the influence of total swell-shrink ratio should be considered besides the degree of compaction and CBR value; and it is helpful to understand the engineering properties of expansive soils. At last, the structural shape of weak expansive soil embankment and the standard of controlling compaction of weak expansive soil for constructing embankment are suggested.

No guidelines are available on liquefaction evaluation of silt-clay and silty sand-clay mixtures under cyclic loading. The liquefaction behavior of these kinds of soils is not understood clearly at present. In this paper, according to the results of dynamic triaxial tests, the characters of cumulative pore water pressure and dynamic deformation of silt-clay and silty sand-clay in Tianjin are analyzed. The liquefaction evaluations of indoor tests are studied. At the same time, the results of wave velocity test in situ are compared to that of the indoor tests. As results, for the silt-clay and silty sand-clay in Tianjin under cyclic load, the value of water pore pressure tends to be stable when it is equal to 60 %-80 % of confining pressure; the corresponding value of double amplitude strain is 5 %. Therefore, these values can be used as the indexes of liquefaction evaluation.

The compression coefficient in settlement calculation for vacuum preloading is based on the oedometer test, but the stress state in ground for vacuum preloading is different from oedometer test, the results of settlement calculation is unreasonable used parameter from oedometer test. The theoretic analyses in elastic condition, compression test by trixail apparatus with automatic controlled stress that can simulate the stress path in vacuum preloading, and field monitoring in project of vacuum preloading are presented. The ratio of isotropic to one dimensional consolidation in elastic condition under same load, compression coefficient from trixial test and oedometer test are discussed. Settlement results of field monitor and calculation show above consideration is reasonable.

A new probability formula of block volume considering randomness of spacing and extension of joint planes is established by means of block theory and probability analysis. The relationship among spacing, extension and block volume is analyzed according to the formula. The traditional hemispheric projection method handled quantification index of block volumes is conquered; and the index can be obtained soundly by the formula. The applying prospects and adaptation of the formula are shown by project examples.

The massless base model and viscous boundary base model are still the most widely applied approximate methods for easiness though many approaches have been proposed for the seismic response analysis of soil-structure system. But there are some problems in the application of various of approximate dynamic unbounded soil model. In this paper, detailed formula for the soil-structure dynamic interaction analysis is derived; the concept and the application criteria of mass-less base model and viscous boundary base model are clarified; and a simplified soil model for dynamic soil-structure interaction analysis is suggested.

Field investigation has shown that the excess pore water pressure induced by deep mixing column installation may be higher than the hydraulic fracturing pressure. The interaction behavior between the deep mixing column and the surrounding soil can be simulated as the shearing-expanding process of a cylindrical cavity. An approach is proposed to analyse the soil fracturing due to tensile force. Analytical results indicate that the rotation of the mixing blades has a significant effect on the clay fracturing in a close region around the column. The proposed method has been verified against laboratory test. Fracturing cracks have two functions: firstly, cement slurry can flow into the fracturing crack; secondly, excess pore pressure may dissipate through fractures. These two effects speed up the strength recovery of the surrounding soil.

Scattering of SV waves by a cavity in a layered half-space was analyzed by indirect boundary element method in frequency domain. The free-field displacements and stresses were calculated on the line which will form the surface of the cavity. Then fictitious distributed loads were applied on the same line to calculated Green’s functions for displacements and stresses. The amplitudes of the fictitious distributed loads were determined by the boundary conditions, and the displacement response arising from the waves in the free field and from the fictitious distributed loads were then summed up to obtain the solution. The amplification of the incident SV waves by a cavity in a homogeneous and a layered half-space were compared; and numerical results showed that larger surface displacement amplitude may be resulted in the case of layered half-space, especially for low-frequency waves.

Method for nonlinear consolidation of underconsolidated clay under arbitrary loadings is paramount in engineering practice; however, few solutions in this area have been available. By the method of Laplace transform, according to the Gibson’s governing equation for one-dimensional consolidation of saturated thick clay layers, a short paper has studied the behavior of this kinds of soils. Results are presented by the inverse Laplace transform. The solutions manifested that the degree of consolidation and the settlement are depended only on the parameter (governing equation parameter), and the development of the degree of consolidation as well as the normalized void ratio is a vibrant process under arbitrary loadings such as cyclic loadings, the degree of consolidation lags the imposed loadings and the amplitude does not reduce as time goes on. Method presented in this paper can be adopted to calculate the degree of consolidation and the void ratio of underconsolidated saturated soft soils under arbitrary loadings at any instance T with different boundary conditions (pervious and impervious). The results are meaningful in engineering practice.

An updated elastoplastic model is presented. The model turns to the updated Cam clay model’s yield function to describe the characteristics of damaged soft-clay and suggests a new varied law of the damaged variable. Owing to Cam model based on the remolded samples test, the remolded soil characteristics can be exactly described. The Cam parameters possess a comparatively perfect detecting methods and accumulate various empirical values. The updated elastoplastic model can be easily popularized and applied to engineering.

In general, the calculation of earth pressure existing in the back of retaining wall employs the classical earth pressure theory; and the earth pressure distribution along the wall back is linear. In practical engineering, however, the earth pressure distribution usually is nonlinear. In order to enhance the accuracy of earth pressure calculation, it was assumed that the potential slip surfaces of backfill soils were composed of log-spiral surface and plane. Based on the existing researching works, the formulae for calculating active earth pressure were obtained by utilizing thin-layer element method. Since the calculation value of earth pressure is relevant to the location of slip surface; in the search for the most dangerous potential slip surfaces, a new hybrid genetic algorithm, called complex genetic algorithm (CGA), was developed by introducing complex method into simple genetic algorithm to enhance the calculation efficiency. CGA was used to determine the potential slip surfaces and calculate the corresponding active earth pressure. Finally, the earth pressures of the laboratory model retaining wall and in situ retaining wall were analyzed and the results show that the calculation values given by the presented method are very consistent with the measured values. It is indicated that the presented method is feasible and reliable.

Based on a series of consolidation tests for undisturbed samples in Guangzhou Nansha, the influence of stress history, load ratios and overload pre-pressure on secondary consolidation properties has been researched. The results show that the separation of primary consolidation and secondary consolidation is related to load ratios, which effect to secondary consolidation ratio C? also. Secondary consolidation was mainly affected by preconsolidation pressure pc. As p pc, C? presents different regularities. After preloading, the secondary consolidation ratio C? and compression index Cc is a constant: C?/Cc≈0.03. The test results indicate that character of secondary consolidation depends on preconsolidation pressure, which provides a perspicuity idea for reduce settlement after construction.

Dynamic interaction effects of a giant pier-pile group-soil system are investigated by a stochastic seismic response method. A complex response technique is employed in this method. The interaction system as an integrality is modeled by some finite elements and the dynamic nonlinearity of soils is considered through the equivalent linearity method. Stochastic seismic analysis of the free ground and the interaction system are carried out respectively; and their results are compared. The comparisons indicate that the effects of interaction are related to the modulus variance of pile and soil, and the distance of soil and pile foundation. The dynamic shear strains of soft soils have significant difference. The distributions of shear strains near the both boundaries of pile group appear to be curved. The peak acceleration values of ground surface and superficial layer obtained from seismic interaction analysis are smaller than that obtained from seismic free ground analysis. But, the peak acceleration values of deep layers have increases of 5%-30%. In addition, the frequency components of ground surface motions have marked difference for seismic responses of free ground and interaction system. Therefore, the dynamic bridge structure-pile group-soil interaction should be considered properly for the seismic design of bridge foundations.

Relation between the snap-back (Class II behavior in rock mechanics) of axial stress-axial strain curve of rock specimen in uniaxial compression subjected to shear failure in the form of a single shear band and the snap-back of axial stress-lateral strain curve was investigated analytically. In strain-softening stage beyond the peak compressive stress, the axial and lateral elastic strains were determined by Hooke’s law, while the axial and lateral plastic strains were derived by gradient-dependent plasticity where an characteristic length controls the thickness of shear band. The axial and lateral plastic strains are concerned with the compressive stress level, the inclination angle and the thickness of shear band, the softening modulus, and the geometrical size of rock specimen. According to the signs of the post-peak slopes of axial stress-axial strain curve and axial stress-lateral strain curve, the conditions of axial and lateral snap-backs were proposed. The reason for axial snap-back is that the recovery of axial elastic strain is faster than the increase of axial plastic strain. Similarly, the reason for lateral snap-back is that the recovery of lateral elastic strain is faster than the increase of lateral plastic strain. If the tangent of the inclination angle of shear band is less than Poisson’s ratio multiplied by the ratio of width to height of the specimen, then the snap-back in axial direction occurs once the lateral snap-back takes place. Otherwise, the lateral snap-back occurs when the axial snap-back takes place. For the commonly used rock specimen (height/width is about 2) in laboratory, the lateral snap-back leads to the axial snap-back. In the strain-softening stage, the axial strain-lateral strain curve can be classified into four categories: axial snap-back and lateral snap-back, axial snap-through (Class I behavior) and lateral snap-through, axial snap-back and lateral snap-through, and axial snap-through and lateral snap-back. Conditions of these four kinds of cases were presented.

Aiming at the aeolian soil in the West Area of Liaoning Province, the moisture transfer of the freezing process is tested; and the change law of moisture content with time and temperature are obtained. A dynamic coupling model of moisture transfer in the freezing process is established based on the theories of continuum mechanics and the thermodynamics; and the numerical simulation analysis is studied by using difference method. From microscopic viewpoint, the permutation of soil grain is studied via the scanning electron microscope, which reveals the moisture transfer characteristic of aeolian soil. The results indicate that a peak of frozen moisture content is formed in frozen peak surface, which is developed for depth change with time increased. Time and temperature decide the sufficiency of moisture transfer, and the change of temperature wane with the increment of depth. From scanning pattern, we can draw that the fresh arrange of soil grain directly reflects the state of moisture transfer.

Based on gray theory, an unequal step length gray differential equation was presented to describe bearing capacity of overlength piles, and obtain its accurate solution. Error objective function was created based on optimization theory, further used least squares method to get the system parameters of the differential equation. In order to improve the accuracy of model, according to Markov theory, dividing the test value of gray optimizing model into n kinds of states based on predicating fitting curve, and getting one-step transfer matrix to forecast bearing capacity of overlength piles. The predication results show that the gray optimizing -Markov model based on the load-settlement curve can improve the precision of prediction compared with GM(1,1) model and gray optimizing model. A new way is provided for the predication of bearing capacity of overlength piles.

The micromechanics is used to establishing a constitutive model and a seepage model of seeping rock in compression. The process of swelling distortion caused by shearing and seeping are considered for the equations during establishing the constitutive models. An anisotropic seepage model, thingking about microcrack extending, distortion and hydraulic pressure, is established. The frictional sliding, mode-Ⅱself-similar growth and kinking of closed microcracks under compression and their influences on the mechanical properties of rock are studied in detail.

A series of field full scale tests on single PTC (prestressed thin-wall concrete) pile with cap and composite foundation with twin PTC piles with cap have been carried out to cater for the application of a new sparse piles composite foundation in Suzhou-Shanghai Expressway. Based on the data obtained from the tests, the interaction mechanism which is among the pile, the soil under the cap and the soil out of the area of the cap are studied; the load-bearing characteristics of the pile and the soil are elaborated one by one, and the effect that the soil lagging the pile in the development of load-bearing are analyzed, as well as the effect that the soil reducing the load-bearing capacity of the pile. The results indicate that there are two stages when settlement occurred, at the first stage the settlement is controlled by the pile and the next is by the soil. Finally, the changing rules of pile-soil load sharing ratio and stress ratio at the different settlement stages are discussed; the method of designing the dimension of the cap and proposal of eliding the cushion of the composite foundation are presented.

Modified Cambridge model has been widely applied to geotechnical engineering; and it is important to decide the values of parameters in this model. One of the efficient ways to obtain these values is the back analysis based on the measured displacement. The finite element method is used to calculate the horizontal displacement at the front of the pier improved with drilled grouting piles. The changes of the displacement at that point with each parameter are analyzed. The results show that the four primary parameters are the dimensionless parameter related to elastic modulus, the exponent related to elastic modulus, Poisson’s ratio and the test constant of the virgin curve of isotropic loading, which have great effects on the displacement. This result may provide the basis for choosing the parameters for back analysis

Soil arching effect is an important precondition of adjacent pertaining or anti-sliding piles working safely and cost-efficiently. In cohesive soils, the spacing between adjacent piles is related to arching effect. By means of the analysis of mechanical concepts, taking geometrical characteristic of arch line and the fracturing face direction angle of Mohr-Coulomb failure to account, the force-balancing condition and strength condition are integrated and simplified to a uniform expression, which is only presented by the normal stress on the cross section plane of arch foot. Based on Mohr-Coulomb failure criterion, the least handy soil strength parameters which only including cohesion c and internal friction angle ?, according to the relationship between the normal stress and arrow-span ratio, the arch line and spacing between piles are obtained. Furthermore, the depth stable condition of soil arch is discussed, pile spacing can be emended more rationally. The application consists with practice projects to a certain extent. A concise estimate method to soil arch effect may be put forward.

Argillaceous siltstone is a kind of soft rock, which is widespread during Cretaceous to Eogene in China. The potential bearing capacity of this rock is relatively larger. But the bearing capacity evaluated with current Code is quite different to that obtained on site test. The correlation between pressuremeter test (PMT) and uniaxial compressive test on sedimentary rock are studied; and the correlation equations are established for characteristic parameters of PMT and compressive strength. The result of analysis shows that PMT is rather effective for determining the bearing capacity of this kind of soft rocks and is deserved to be applied to practical problems such as those on soft rocks.

Starting from the principle and the mechanic characteristic of forming soil arch of laterally loaded piles, and based on static equilibrium of the soil arch between two piles and soil resistance on its two end sections near two piles, the computation model is put forward. The equations involved space between two adjacent piles, thickness and height of soil arch are provided. One of the three parameters assumed, the other two could be solved. If one of thickness and height of soil arch is assumed, space between two adjacent piles will increase with shear strength parameters of the soil between two adjacent piles. Based on the characteristics of excavation engineering’s earth pressure, suggestions are given to deal with it. Landslide was cited to verify the formulae. The computed result is 1.85 m; and the anti-slide piles spacing which was used in the field is 1.8 m. The computed results are consistent with the evidence in the field.

The occurring and developing of soil cave is the base of karst collapse; and critical soil cave is the final developing phase. In time and space, the critical soil cave can divide the whole developing process of karst collapse into two phases: inter-collapse phase and surface-collapse phase. The inter-collapse phase is the developing and enlarging process of soil cave in over-layer soil, and the failure of superstratum soil above soil cave is similar to the failure of apical plate surrounding rock of underground cavity. Therefore, based on the equilibrium arch theory of М•М•Протодьяконов , the maximum height of limit equilibrium arch of superstratum, which is the limit equilibrium height of critical soil cave, can be determined. In addition, an evaluation of a critical soil cave of karst collapse at Tangshan Palaestra in Hebei Provinces, was completed using limit equilibrium height expression. The results show that the height of critical soil cave by calculating accords with fact, and the error only is 4.3%.

The numerical simulation method for the ultimate bearing capacity of ground is presented by adopting the theory of finite element strength reduction; and the significance in bearing capacity of the ground of the dilatancy angle of the material for the ground is discussed. An example is given; and its results show that the ultimate bearing capacity of ground is increased with the increasing of dilatancy angle; therefore, it’s of great need of considering the dilatancy angle of the ground material, when the ultimate bearing capacity of the ground is accounted.

Base on the static loading tests on prestressed high-strength concrete piles with strain gauges at the top and toe of pile and at interfaces of soil layer, the load transfer mechanism of PHC piles was studied; and the behaviors of skin resistance and inner force were analyzed. Based on the static load test on prestressed high-strength concrete piles (PHC piles) of a practical engineering, using the elastoplastic model, nonlinear interface elements and nonlinear soil elements, by the finite element method, pile-soil interaction of PHC pile in the soft soil area were simulated. The results of analysis indicate that there are many differences between the numerical predictions and the experimental results; however, it shows that the calculated distribution trend is in good agreement with the experimental results.

The research of time-effect on vertical bearing capacity of single drilled grouting pile in saturated soft soil is few at present. Through analyzing the mechanism of time-effect on bearing capacity of single drilled grouting pile in saturated soft soil and in-situ test, it shows that the frame intensity of the disturbed soil around the pile come back lentamente with the time went by. The friction between the soil and the pile enhanced slowly, it shows stated time-effect. The research indicates that the time-effect on vertical bearing capacity of single drilled grouting pile in saturated soft soil can’t be enlarged at actual test, the time-effect can affect more than 10 percent of the ultimate bearing capacity of single pile.

In order to analyze the mechanical mechanism of compression grouting and give the analytical solution of the ultimate grouting pressure, the process of compaction grouting is considered as the question of cavity expansion in infinite soil mass. The ultimate grouting pressure is given by the law of conservation, in which the volume change of cavity expansion is balanced with the compression of soil and the energy given out from cavity expansion is absorbed by the volume change and shear strain caused in soil. The stress-strain-volume change relationships under the high stresses caused by compression grouting are described. The theoretical values agree with the measured values from the field test; and the conclusion that the grouting pressure of columniation cavity is higher than the sphere cavity is gained.

Only one key monitoring data of the monitoring station instead of the others can be used to the prediction model at the same time in the landslide at present. In order to overcome the human factor and make full use of the monitoring information of the multi-stations, the technique of multi-sensor target tracking is proposed to use to deal with the multi-station monitoring data of landslide in view that landslide has mobility in this article. The feasibility is also analyzed. Finally, an example simulation is given in order to illustrate the effectiveness of the method in application.

The maximum height of the intake side slope of Xiangjiaba Hydropower Station is 150 m. Systematic Bolts will be adopted to reinforce the rock mass. Because of the passivity action of systematic bolts and the heterogeneity of rock mass deforming, systematic bolts have different stress in different position. This paper analyzes the systematic bolts’ stresses on rock mass of high side slope of the intake in Xiangjiaba Hydropower Station by using elasto-viscoplastic finite element method. We can find the obvious laws from the calculation results that the bolt stress is larger in the rockmass which has larger displacement than in one which has less displacement. And the bolt stress increases with the excavation and anchorage progresses.

The deformation and stress of freezing soil curtain are analyzed by numerical method during the construction of connected aisle at Dalian Road tunnel; and the stability of freezing soil curtain is also evaluated. The distribution laws for displacements and stresses of freezing soils due to the excavating soil are also discussed in detail. Based on the above research, the most dangerous positions of freezing soil curtain lie in the interface between the soil curtain and the built tunnels. It should be noticed more carefully during construction due to the worse effect of freezing here. For alike projects such as freezing soil curtain in Shanghai, the freezing soil curtain with 1.8m thickness can satisfy the demands of construction. Therefore, this paper could be available for the construction of the connected aisle in theory and practice.

According to reinforcing and adjusting of several incline villas with pile foundation building in Taihu Lake, based on the study of design, constructing and a long period of settlement monitoring, the reason of the villas incline is analyzed; and how to driven new reinforced pile press close to pile already existed , and fasten them together, is studied. A new method for incline pile foundation adjusting is put forward, which increase pile settlement through disturbing around the pile under the load of the structure. Monitoring settlements indicate that the method put forward is effective and economic, and also prove that when calculating settlement and load of each pile, assuming structure and foundation as rigid accords with the fact.

For the improvement of soft soil foundation by cement deep mixing method, the principal factors influencing column quality are the types of solidification agent, the addition ratio of mixed cement and construction technique. Authors briefly introduce the field experiment and the test results carried out in the improvement of Lianyungang marine soft soil foundation by cement deep mixing method. This research indicates that slag cement should be chosen as solidification agent for the treatment of Lianyungang marine soft soil, and the ratio of addition should be more than 21 %; adopting the grouting technology of variation of cement addition along the column shaft (more cement addition in the upper section than the lower part) can improve the column quality of the upper part and the working property. The research would be potential reference to the similar engineering.

The reliability of seepage prevention system is a key problem for high rockfill dam built on the foundation of large overburden depth. Considering the practical characteristics of Pubugou Hydropower Project, the stability of the dam, the deformation and the stresses of the joint zone connected the core wall in the dam and the concrete cut wall in the large overburden depth are analyzed by the adaptive finite element method. And then the advantages and disadvantages of the different type of joints are also discussed; finally, an appropriate type of joint is recommended to the designers.

The simulation of excavation and support on the deep pit of the Yangtze River in south was carried out using the software FLAC3D. During the simulation, the Mohr-Coulomb model was used and contact elements were applied on the interfaces between the structure and soil. This simulation offers the settlements of ground uplifts in the bottom of the pit and horizontal displacements of the soil behind the vertical wall in every step.