Based on Perzyna’s fundamental assumptions of the elastic viscopalstic theory, a viscoplastic flow rule, and Yin and Graham’s 3-D elastic viscopalstic constitutive model (3-D EVP model), the formulation under a triaxial stress state is obtained. Yin and Graham’s model proposed new concepts such as “equivalent time”, “instant time line”, “reference time line” and “limit time line”. The derived formulation is used to simulate the time-dependent stress-strain behavior of consolidated undrained triaxial tests of a soft rock. The simulated results are compared with the triaxial test results. The comparison of the results shows that agreement between the model predictions and measured results is good. This demonstrates that the EVP model can be used to describe the time-dependent stress-strain behavior of the diatomaceous soft rock.

Vague information widely exits in parameters used for analyzing geotechnical engineering. After the distribution of eigenvalue of samples had been studied, it was indicated that the vague factors in parameters could not be ignored. According to the membership function of parameters, the equations of fuzzy eigenvalue of sample parameters was deduced. Its reasonability was also proved. The case study indicates that the fuzzy method is better than the classical stochastic method because its variance is less than the results obtained by stochastic method in any case. The results also indicate that the fuzzy statistic method is worth of being generalized in engineering application.

Based on theoretical analysis and numerical calculation, it is shown that the wrapped phase curve and phase wrapped number in frequency domain are influenced by frequency resolution. The influences of the Rayleigh , dilatational and shear waves reflected from the boundaries on spectral analysis are also discussed .The precision of phase velocity calculation can be improved by the frequency zooming and the signal cutting techniques. When phase data are poor in lower frequency domain, the least square method can be used to rectify the error of phase velocities caused by the additional or missed phase wrapped number.

Based on the wave propagation equation in unsaturated soils, four kinds of waves (i.e., one is S wave, and other three are P waves, P1 wave, P2 wave and P3 wave according to the wave velocity) are found in unsaturated soils through theoretic deduction. Analytic expressions for wave velocity and attenuation are proposed. Numerical analysis about the relations between the wave velocity ,attenuation and the frequency, saturation degree is carried out. The results show that the velocity of P3 is minimum and the attenuation of it is maximum, the velocity of P1 is maximum and the attenuation of it is minimum, and the velocity and attenuation of . P2 are between other two waves. All four kinds of waves are dissipative waves. In general case, the velocity becomes slower with the the frequency heightening, and the attenuation becomes greater. With the gas content becoming higher, the velocity of P1 becomes lower and velocity of P2 and S becomes higher, the velocity of P3 is not affected by gas content very much, the attenuation of P1 wave and P3 wave become less, but not very much. The attenuation of P2 wave is not varied with the change of gas content basically and the attenuation of S wave is very small.

This paper presented the test results of two large diameter short-belled piers, a deep loading test and a friction pile in sand-cobble layer at the same test site, and accordingly gives a study on the belled piers (embedded depth of 6.20 m-6.75 m) load transfer behavior. The analysis shows that the pier ultimate bearing capacity can be confirmed by direct test method and indirect test method. S3 pier (bearing layer is cobble layer) ultimate bearing capacity is 7 250 kN, end resistance is 6 890 kN, taking up 95 % of the ultimate bearing capacity, and S2 pier (bearing layer is sand layer) ultimate bearing capacity is merely 2 330 kN, end resistance taking up 85 %. When the settlement of loading pier is about 1.46 mm, the skin frictions of pier S3 and S2 have achieved ultimate state; but when the end resistance in ultimate state, the settlement of pier S3 and S2 are 92.64 mm and 21.07 mm; respectively. The vertical bearing capacity of belled pile is greater than the pure friction pile and shaft as their diameters are equal.

Casing damages during injecting well blowout have taken place commonly in many oil fields in China. In order to study the mechanism of the casing damage, fluid-solid coupled model to simulate casing stress and deformation is established; the numerical simulation based on the finite element method is also given. The simulation results show during the blowout process, the geo-stress around well-bore changes. At the beginning of the blowout, the tangent and radial stresses are big. The simulation results are very helpful to the casing protection in oil fields.

The relationships among mechanical indexes, swelling-shrinkage properties, pore size distributions and moisture contents of lateritic clay in Guigang of Guangxi Zhuang Autonomous Region, are discussed through experimental research on the heavy-pattern compacted samples. The results show that the dry density can reflect the strength rule of compacted lateritic clay as a whole, and the moisture contents of unsaturated compacted samples corresponding to the maximum of strength indexes are comparatively low because of the effect of matrix suction, while those after saturating increase obviously duo to water absorbing, swelling and the loss of matrix suction. For lateritic clay compacted under the condition of optimum moisture content, its strength is not the highest after saturation although a very high compaction degree is obtained. The swelling-shrinkage properties of compacted lateritic clay are mainly controlled by moisture content, and also affected by dry density. The pores of compacted lateritic clay are mainly small sizes in diameters from 0.01μm to 0.05μm, which is useful for the further mastery on the geotechnical properties of lateritic clay.

The four kinds of rock’s acoustic emission(AE) characteristics are tested and analyzed under uniaxial compression. And under crushed statically by gesso and cement mixture, AE characteristics of rock-mass are studied. As results, at lower stress the rock seems to has no AE. In general, when stress arrives at 80 % of rock strength, and rock draws near breach, its AE just increases remarkably. And AE progress of rock breakage is divided into four phases, viz., beginning phase (Ⅰ), tempestuousness phase (Ⅱ), drop phase (Ⅲ) and dreariness phase (Ⅳ). And that Kaiser Effect of some rock is unobvious. Also dominant frequency of rock AE is related to its strength. The more its strength is big, the more the dominant frequency is big. And when the stress increases, the dominant frequency is not budged. In addition, the 1 kHz sensor is suitable to analyze stability of rock-mass and forecast its fall.

The deformation of a slope and landslide is a very complex problem, and is an importance index value of forecasting and prewarning the landslide hazard. The displacement of slope due to rainfall is related to suction and the stress-strain behavior of unsaturated material. According to test data, the effect of suction on the stress-strain behavior of unsaturated soils is researched; and the moisture content-strain behavior of unsaturated soils is built. Based on this, the mechanism and regularity of slope the displacements due to rainfall have been discussed. The Wudu landslide is analyzed by this theory.

This study make use of the wholly grouted groups of bolts for static-load testing of piles instead of the counter-force piles, which is not only technically simple and convenient for construction, but also short in the period of project and economical cost of construction. Based on the mechanical analysis and the in-situ observations, the forcing and displacement characteristics of the bolts are obtained so as to provide the theoretical basis for design and calculation of this type of bolts.

A series of model tests have been described for the adjustment of penetration of three-bucket foundation platform that is to be located in the JZ-93 island area, Bohai Sea, China. This also was the first time in the country to use the multi-bucket foundation to the platform. Though many suction anchors have been installed before, there is no experience in installation of the multi-bucket foundation platform. As the result, the model tests have certain effects to guide the construction procedure and feasibility of full-scale structure.

The stability of large underground cavern has high dependence on construction sequences and permanent support parameters. Longtan underground powerhouse is a complex structure with three large caverns and located in high dipped laminar strata. FLAC3D code is applied to analyze the character of deformation and failure mechanism of surrounding rock mass during excavation and support. Furthermore, the comparison between numerical results and field measurements shows that the variation law is quite similar, while the numerical data are a little greater than that of the measurements. It can be concluded that FLAC 3D can simulate excavation of large underground caverns in high dipping laminar strata well.

Rock mechanical properties are the essential parameters in the application of petroleum engineering and they could be obtained through laboratory experiment under simulated strata conditions. These measured properties are only for certain formations, so continuous formation properties used in strata engineering are usually from logging data. Nevertheless, result discrepancy exists between these two different methods due to the difference of loading frequency and only could those obtained from logging be applied in petroleum engineering after certain calibration. To obtain calibrated continuous logging data from laboratory tests, static and dynamic properties of formation rock under simulated strata condition were primarily studied.

A contrast analysis of the local static load test data of 8 piles for a coal mine loading bridge is carried out by using random-fuzzy linear regress method and traditional random regress method; and more precisible relationship between the last press-pile force and the ultimate bearing capacity of static pressure pile is obtained; and meanwhile it is shown that using random-fuzzy method to analyze the random-fuzzy test data is more reasonable and accurate.

The stress wave 's property when piling viscoelastic pile is discussed mainly. And the analytic solution of the pile's portrait vibratory velocity is given. The coefficient of viscosity and effects of stiffness of pile tip soil on the pile's vibratory velocity response are analyzed.

There are some special issues that cause difference to predict fluid flow in fractured vadose zone, including capillary flow, film flow, preferential flow and fracture-matrix interaction. Those issues can bring on notable unevenness of local velocity and flux in fractured vadose zone. The features of those issues are studied. In addition, alternative conceptual models for flow in fractured vadose zone, such as macroscale continuum models, high-resolution finite differences models, discrete fracture networks models, percolation models and weeps models, are discussed.

Because that new tunnel is close to existing tunnel, the vibration wave induced by blasting endangers the safety and stabilization of existing tunnel structure. The means of in-situ testing and numerical analyses for studying this question are carriedout; and some conclusions are drawn.

On the basis of appraising the existing analytical methods of slope stability, the plastic limit analysis using finite elements is put forward to analyze the slope stability. By using the idea of finite element method and linear programming, the limit analysis models of mathematical programming for slope stability are established; the model can evaluate the safety factors of lower bound and upper bound, and can give the stress field of lower bound and the velocity field upper bound at the same time. Finally, taking a classical heterogeneous soil slope for example of calculating slope stability, the comparisons among the analytical results of various methods are made. The results show the correctness of the method and the program.

The shape and location of the sliding surface was confirmed by engineering investigation and displacement monitoring of the landslide of Jiao-Liu Railway project, and the thrust transfer coefficient method was performed to analyze the stability of the landslide, in which the influence of groundwater was taken into account. The strength indexes of soil on sliding surface, cohesion c and angle of internal friction φ, were obtained by back-analysis based on least-squares method. It shows that the method can analyze quantitatively the contribution of dewatering to safety factor of the landslide, so that the retaining structure is designed economically. The strength index that solved by multi-sections’ data represents the overall character of the soil on sliding surface, which reduces the randomness influence of tested data. The method and the conclusion can be used for reference by similar projects.

International Society for Rock Mechanics ( ISRM ) proposed in 1995 a new type of rock fracture toughness specimen——cracked chevron notched Brazilian disk ( CCNBD ), the previous analytical and numerical studies of the dimensionless stress intensity factor, which is an important mechanicel parameter, does not take into account the effects of finite notch width. Since the minimum chevron notch width is limited by the size of the cutting wheels used to produce it and can not be zero, as the specimen size get small enough, the notch width would become large in relation to the sample size. Our 3D BEM(Boundary Element Method) calculation shows that the larger the notch width is, the bigger the error makes for the dimensionless stress intensity factor. To the standard CCNBD specimen suggested by ISRM, this paper determines the minimum dimensionless stress intensity factor to be 0.954 which is 13.6 % larger than the value 0.84 given by ISRM; and the tread of the curve is changed when the crack is short, this could make the failure of the experiment. We recommend that a full 3D numerical analysis taking into effect of the notch width to be done whenever determine the dimensionless stress intensity factor.

Depending on the method based on the stress wave theory to calculate the peak particle velocity(PPV) induced by blasting,an equation to calculate the blast-induced damage zone in rockmass is educed. In accordance with the PPV criteria for blast-induced damage, the blast-induced damage zone is calculated for the blasting excavation of the diversion tunnel at the right bank of Longtan Hydroelectric Project. Analysis and comparison between results of the calculated and measured blast-induced damage zone with method of sonic measurement are presented.

Surrounding rock of underground engineering has high nonlinear characteristics, so its mechanical behaviors can be studied and predicted by nonlinear theories. Research of stability of surrounding rock with dissipative structure and catastrophe theory helps to unveil procedures and causes of rock failure and to develop a method of solving stability of surrounding rock .

The parallel buried pipelines will be damaged by soil movements around pipe induced by pipe jacking. The displacements of parallel buried pipelines induced by pipe jacking are analyzed by 3D-FEM. Displacements of buried pipeline affected by injection slurry, alignments, the distance between pipeline and pipe jacking axis, the depth of buried pipeline, the materials of buried pipeline, the elastic modulus ratio between buried pipeline and soil are studied. The analysis results show that the more pressure of injection slurry and alignments, the more displacements of buried pipeline; the more buried pipeline apart from pipe jacking, the less displacements of buried pipeline; the more elastic modulus of buried pipeline, the more displacements of underground pipeline.

A rockburst mathematical model is established by three layers neural network; and a new algorithm which is called asynchronous iterative algorithm with relaxation factor is trained the model. The algorithm has a better speed and avoids local minima and paralysis in some degree. As a results, maximum magnitude of rockburst is forecasted. The paper adopts 1999—2000’s field rockburst data of Huafeng Coal Mine of Xinwen Mining Company and turns rockburst energy, wave amplitude and frequency into neural network input, turns related maximum magnitude of rockburst with above data into neural network output. So, we set up three layers forward neural network with three input nodes, seven hiden layers nodes and one output node. The paper selects 35 groups from 40 groups in 1999—2000 year and turns it into training groups, the remains is regarded as testing groups. The training program is designed by Matlab 6.1. After 50 000 iterations, the network error is 0.06 and the value is under the network’s error precision. So, the network is convergence. At last, average error between the network forecast value and testing value is 9.2﹪,the result verifies that the method is successsful.

The stress distributions in soil under composite foundation with soft base slab and stiff base slab are very different .The methods of stress and settlement used frequently are based on the composite foundation with stiff base slab. The results of these methods are not fit with the actual. Using Mindlin solution and Boussinesq solution, the additional stress and settlement are acquired. Using Vesic theory, the earth-arc effect on pile top are acquired. Compared with the test results, the stress and settlement are best agreement with it.

The analytical solution to ground reaction curve of surrounding rock can only be obtained for a circular tunnel; the horseshoe-shaped tunnel, therefore, has to be converted to a circular one. In addition, there are other difficulties such as the determination of initial ground data, initial geostress field and displacement, so it is difficult to design a regular tunnel lining, especially a standard tunnel lining, with the convergence-confinement design method. In the paper, the ground reaction curves of single and double track standard railway tunnels are drawn for different surrounding rock classification and tunnel depths. Furthermore, the variation rules of ground curve of surrounding rock are analyzed for different surrounding rock classification, tunnel depths, tunnel shapes and sizes. It is of practical significance for the application of the convergence-confinement method to the design of railway tunnel lining.

Based on Biot’s theory of consolidation, an analytical solution of stress, displacement and pore pressure induced by time-dependent axisymmetric load or fluid pressure applied on the boundary of tunnel in a transversely isotropic soil is obtained in the Laplace transform domain by uncoupling the governing equations, in which the soil is assumed to be poroelastic material with compressible constituent. By numerically inverse Laplace transform, the results in time domain are obtained and used to discuss the influence of instantaneous loading, one step loading, and cyclic loading, and transversely isotropic property of soil on the stress, displacement and pore pressure fields.

A new ground improvement technology, cement fly-ash steel-slag pile, is presented. By piling up steel blanks to simulate the bearing properties of CFS pile composite foundation during service, some bearing characteristics including the settlement of foundation base, the deep horizontal displacement and the distribution of vertical additional stress of composite foundation, the horizontal displacement and the variable rhythm of lateral additional stress of adjacent excavated hole pile etc., are studied. The interaction mechanism of CFS pile composite foundation-adjacent excavated hole pile during superficial surcharge is also discussed. In addition, the environmental effect due to the construction of CFS pile is studied; the variable rhythm of lateral additional stress of foundation with distance and depth and the land upheaval value in A and B region are obtained.

Considering the existing designing defects of the pile/wall retaining system, a new method of structural design optimization is put forward. After determining the decision variables, constraint conditions, objective function, optimization algorithm and the computer programming , the structural optimization about decision variables is successfully carried out.

The well resistance affects the rate of consolidation of treated ground, the discharge capacity of prefabricated vertical drains relates directly to the well resistance; the smaller discharge capacity, the more well resistance; but the more discharge capacity, the more costs of prefabricated vertical drains. In this paper, the effect of consolidation due to the discharge capacity of vertical drains is analyzed; and the method for selecting the discharge capacity of prefabricated vertical drains for different treated ground is given. It is suggested that the discharge capacity of prefabricated vertical drains satisfying can be the criteria whether to consider the well resistance or not.

The whole excavation operation of a highway unequal-span double-arch tunnel is simulated by a finite element software called GeoFBA2D. This highway unequal-span double-arch tunnel consists of a big tunnel and a small tunnel. Attentions are mainly focused on the stress and displacement of the surrounding rock mass, the stress between the first linings and the second linings, and the stress and displacement of middle-wall so on. The results show that the maximum tensile stress of the big tunnel vault is 4 times of that of the small tunnel. The effect of unequal-span double-arch’s performances are quite distinct. The displacement of small tunnel vault can be divided into three obvious stages: before the excavation of small tunnel; during the excavation and lining of small tunnel; during the excavation and lining of big tunnel. The stress between the first and second lining of the small tunnel is smaller than that of the big tunnel. The stress and displacement of middle-wall varies with the construction process, but the ultimate displacement values are very small.

The feasibility of applying soil-nailed support techniques to soft clay foundation pit of 6.0 -7.0m depth is analyzed based on discussing the features of soft clay ground and the support of foundation pit actualities. At the project of Zhenhai Refining & Chemical Company the soil-nailed wall is adopted successfully in 6.0m-depth foundation pit in the super soft soil. It is the first case of soil-nailed wall applied to soft foundation pit in Ningbo urban area; and it creates a precedent for this kind of technique. Because of the particularity of Ningbo soft foundation the possible problems should be predicted and prevented from during the construction. The experience and lesson about the soil-nailed wall design and construction are described in detail and the appropriate support structure type fitting to Ningbo soft soil foundation pit is advanced. Soil-nailed support techniques shall be widely used in Ningbo urban area due to its economy and rationality.

The pile foundation strengthening treatment scheme, pile foundation underpinning, jack up and raft foundation strengthening for the interval shield tunneling from Datang station to Lijiao station of No.3 Guangzhou subway are described in detail. Specially, pile foundation underpinning is described emphatically from such aspects as underpinning principle, mechanical analysis calculation method, key construction contents and technical measures.

The testing results of dynamic compaction on a silty soil foundation of a flood-prevention dam in Yibin, Sichuan Province are introduced. The test data show that: the valid strengthened depth in the foundation is more than 6 meters at the compacting energy of 1 600 kN?m; the average dry density of the soils is increased from 1.48 g/cm3 to 1.57 g/cm3; the average void ratio is decreased from 0.852 at natural state to 0.724 after compaction; the average compression modulus is changed from 5.42 MPa to 8.27 MPa; the average permeability coefficient is decreased to the value of less than one-tenth of the natural state; the arithmetic average of permeability coefficients is reduced from 2.5×10-4cm/s to 3.5×10-6 cm/s; the N-values of SPT at natural state have 32.9 % less than 5 while all of them are more than 7 after compaction. The conclusion can be stated that the dynamic compaction method is suitable for the treatment of the silty soil foundation in the site of the foundation of flood control dam in Yibin. The ground can meet the requirement as the foundation of flood-prevention dam on capacity and seepage stability, as well as the liquefaction prevention at 7-degree earthquake.

The cyclone sedimentation tank in the water treatment shop of super-thin strip rolling machine of Lianyuan Steel Plant is a kind of super big and deep foundation pit which is located at the karst area with safety class I. By adopting “semi-inverse” construction process and unique support structure system in this project (the first time to adopt this kind of technology in China), it is proved to be very successful. The whole course of this new technology from design to application is introduced. It can provide reference to the similar projects.

Based on the design and the construction sequences of the Netlon network and gravel stratum reinforcement in the soft foundation of a fly-ash dam project, the mechanism of such reinforcement method is discussed and computation method for designing is studied. The estimation of the strengthening efficiency is also given. Some helpful conclusions have been drawn.

Based on geological information of the soil dam of the Xianling reservoir in Hunan Province, the seepage of the dam is calculated by FEM and the leakage as well as the percolation failure problem are discussed firstly; then the measures to reinforce the dam are proposed and approved to be reasonable and safety; the methods and conclusions can be valuable for the future safety identification, reinforcement as well as design, construction and management of soil dams.