In concrete face rock-fill dam (CFRD), especially when the dam is high, creeping of the dam body can be critical. In this paper, a numerical procedure is developed to study the influence of the creep deformation on the separation between concrete slab and cushion layer in high CFRD. The procedure is based on the finite element method and the direct constraints method is used to simulate the contact behavior between the concrete slab and the cushion layer. The procedure is applied to Tianshengqiao-I CFRD. Based on a comparison of the numerical results with in-situ measurements, the effects of creep deformation on the separation between concrete slab and cushion layer are investigated.

The pattern transition in stress-strain relations of soils, which is a mechanical phenomenon generally existed in many soils, is revealed for the first time, based on analyzing the data of stress-strain relation tests published in literatures. Two new parameters, post-failure Modulus Epost and critical confining pressureσ3cr, are suggested for recognizing of pattern transition of stress-strain relations of soils. The factors influencing the phenomenon of pattern transition such as soil types, confining pressure, initial density or water content, drainage conditions, stress paths, etc., are briefly analyzed. Finally, a combined model for describing the pattern transition in stress-strain relations of sands is schematically suggested.

Rock joints of 30—50 m away from the earth surface are under lower confining pressure which is about 1 MPa. So it is of actual significance to investigate the flow properties of rock joints under lower pressure. Two hypotheses for rock joint deformation under lower pressure are put forward, of which one is that rock joint is linear elastic, and another is that aperture decrement is much smaller than the initial mechanical aperture. With these hypotheses, a semi-empirical theoretical formula for rock joint under lower normal stresses is developed using Barton’s equation. Experimental tests of marble joints are performed; and the results are consistent with the formula. It is shown that the hypotheses are reasonable, and that hydraulic conductivity linearly decreases with normal stress increasing. Furthermore, an indirect method for measuring initial mechanical aperture is given.

According to the characteristics of geotechnical and underground engineering structures, the variational principle employing modified Reissner functional into which independent rotation field has been introduced. The rotation field is interpolated by true rotation at each node. The rational type of incompatible fields of 4-node element is discussed. The incompatible displacement functions being suitable for arbitrary quadrilateral element are denoted. An internal parameter type incompatible element with rotational degrees of freedom is established and the numerical computation formulae are developed. The element of this paper is proved to pass the patch test. The compatibility with beam elements with rotation freedoms can be easily made. From the computational examination questions as well as the underground tunnel engineering example, it is shown that the numerical results by using the computation model of this paper have good accuracy. A perfect numerical method is developed for analyses and computations of geotechnical and underground engineering structures.

The natural diatomaceous soil widely-deposited in Ohita Prefecture of Japan is a surprising natural sedimentary soil with a normally-consolidated history. Its water content is very high, but its stiffness is so high that it can keep its intact state without suffering from the effects of sample disturbance during sampling and handling. The high quality and strong resistance of soil structure provide a unique chance to investigate the mechanical behavior with intact samples in laboratory. A high-pressure triaxial apparatus is used to perform isotropic consolidation tests and triaxial consolidated undrained shear tests. The results indicate that the compression curve of structured soils is a horizontal line from the initial void ratio in preyield state, and the compressibility changes dramatically in the vicinity of the consolidation yield stress. The strength behavior shows that the strength of structured soils is independent of stress level in preyield state, but the strength envelop in postyield state is a straight line through origin which is similar to that of remolded soils.

Finite element method is a familiar method in settlement calculation of embankment, and the authenticity of soil model parameters is the guarantee of higher accurate results. Firstly, the analyses aimed at influencing degree of Duncan-Chang model parameters to settlement are done; and the five parameters with larger sensitivity are found; Then with artificial neural network technology, a thought of two model parameters modification (K, G) is brought forward combined with measured settlements. It shows that this thought is reasonable and the calculational results with modified parameters are more precise. In a way, it can be reference in engineering.

Given double shear strength theory and true triaxial strength test data on granite, considered different failure strength characteristics of rock for triaxial compressive and triaxial tensile loading test paths, then granite corresponding functions under triaxial compressive state and under triaxial tensile state are expressed separately. By compared granite true triaxial strength test results with predicting results which are obtained by different smooth ridge models, such as Gudehus-Arygris model, Zhen Yingren model, William-Warnke model and Yu Maohong-Liu Fengyu model etc., some beneficial suggestions on these smooth ridge models are proposed.

The mechanical properties of red clay under triaxial stress are studied by using CT technology, which is a new kind of research method in soil mechanics. During the red clay is under triaxial stress, the regularities of clay’s inner structure, pore change, fissure extending and so forth are analyzed from meso-angle; and obtained the CT images and the relatives of the CT numbers and stress- strain are obtained by the new technology.

The basic principal, basic method and general situation of discontinuity surface mapping are summarized. Combined geodesic discontinuity surface parameters in the fields, a mapping method based on mechanics mechanism is put forward on the basis of considering mechanics mechanism of rock fracture. The technology is applied to forecast of overbreak in jointed rock masses openings. The veracity of the result will be tested by an engineering example. The result shows that discontinuity surface mapping considering mechanics mechanism of rock fracture can reflect the configuration of discontinuity and forecast properly overbreak in jointed rock masses openings.

The generalized creep model for jointed rock is derived according to the creep model of rock and joint. With the prerequisite that volume strain of rock and compressive normal deformation of joint are elastic and with no account of shear dilatancy of joint the creep model of rock mass permeated by three sets of joints is derived to take account of viscoelastic deviatoric strain of rock and shear displacement of joint. With the creep models of rock and joints obtained by back analysis for experiment data the influence of some parameters on uniaxial creep of rock mass cut by three sets of intersected joints is analyzed. According to the above analysis the joint interval and shear dilatancy index and angle between two sets of joints have important effect on uniaxial creep of jointed rock. The axial creep compliance and creep deformation of jointed rock are decreased with the increase of joint interval and shear dilatancy index and with the decrease of angle between two sets of joints.

Jinan is a famous city of history and culture, it is also the capital of Shandong province. It is faced serious environmental geotechnical problems day by day along with the quickening of urbanization course. The foundation soils in the typical district of Jinan city were taken as study object. Physical and mechanical effect experiment on chemical action of water on soil were done, undisturbed soil specimens from the polluted erosive foundation were taken, physical and mechanical property experiments were done. The result indicates that there is remarkable change for the physical and mechanical property after foundation soils were polluted. Compared with ordinary foundation soil, the polluted erosive foundation soil has smaller liquid limit, smaller plastic limit, smaller compressibility modulus; and larger liquidity index, larger compressibility factor.

For white marble and limestone specimens of same diameters and different heights, uniaxial compression strength tests are carried out. The regularity that compression strength of brittle rock reduces with the increase of height–to-diameter ratio is certified. Based on the results of compression strength tests and the grey model GM(1,1), the nonlinear equations between uniaxial compression strength and the height–to-diameter ratios of specimens are worked out. This empirical formula for brittle rock is uniform, and the difference of rock strengths with different rock characters and test conditions is reflected by a parameterα. Fortunately, the equations are very convenient to provide consultation and reference for evaluating the strength of the similar rock in the related engineerings.

The extended simplified Bishop method (ESBM) provides another convenient way to calculate the safety factor of non-circular slip. But a new question arises when to format the equations of overall moment equilibrium of the forces acting on each slice, namely, different positions of moment centers can lead to different safety factors. Just so, the application of ESBM is limited. The authors address the question of the effect of the moment centers on safety factor of non-circular slip. Moreover the principle has been suggested to position the moment center in order to obtain relative accurate safety factor. According to analysis of many examples, the results show that it is possible to make the precision of safety factors calculated by ESBM equivalent to that of by rigorous method such as Morgenstern-Price method as long as the moment centers is choose properly.

The horizontal displacement of the composite ground improved by rigid piles is negligibly small, thus the only remaining component is vertical settlement. Equilibrium equations, geometry equations and physical equations are used to derive the governing equation of the problem. Boundary condition at the soil-pile interface is accounted at two different states: the displacements of the pile and the surrounding soil are compatible or slippage is developed at the interface. The displacements of the pile and soil can be solved by finite difference method from the governing equation. Then skin friction on the pile can be predicted. By comparing with finite element analysis and the measured data in site, the simplified method is verified and is convenient to be used in engineering design.

A simulation explosion test is an important method to study the dynamic property of foundation, the soil-structure impactive interaction due to exploding, and the anti-explosion ability and destroyable mechanism of underground safeguard engineering structure under impactive load due to exploding. The design of scale model similitude is one of keys to insure that simulation explosion test can really reflect the dynamic characters of prototype under impactive load due to exploding.To aim at the safeguard effect of superstratum of saturated sand to defence tunnel of circular arch and vertical wall which isn’t destroyed by impactive terra wave as a result of the explosion of bomb falling to the ground, this dissertation will base on the theorem of Bockinghamπwidely applied at present, and a method mainly used is the dimensional analysis method, also the comparabilities of the nonlinear dynamic response of soil-structure system to impactive process of exploding, the dynamic response of soil-structure interface to impactive process of exploding, and the dynamic interaction of exploding impactive terra wave and structure are considered , in order to solve the similitude relation of model design of simulation explosion test of soil-structure impactive interaction due to exploding.

The jointed rock mass possesses complex mechanical behaviors, the ultimate bearing capacity of foundations of jointed rock masses has not been studied in detail from a theoretical point of view. An analytic expression has been developed that enables the shear strength to be determined using the nonlinear strength criterion which takes influence of intermediate principal stress on the yield and failure of jointed rock masses into account. The important concept of instantaneous friction angle is defined. This paper defines a methodology for load bearing capacity quantification based on the nonlinear unified strength criterion and by applying the characteristics method for resolving the differential equation systems which govern the stress field. The boundary conditions are defined by the external load system and the geometrical configuration are incorporated. The closed form solution is obtained. To facilitate an overall understanding of the procedure ,an example problem is solved showing how the initial data are used . Results show that the properties of jointed rock masses and intermediate principal stress importantly affect the ultimate load bearing capacity of foundation.

There are many settlement deformation analyses about soft soil ground in the past engineering practice. With the rapid development of infrastructure construction, the rebound deformation analyses are needed in many engineerings. Deformation properties under unloading have been studied through large numbers of tests. For the ooze’s rebound defamation, a critical unload ratio is existed. When ooze’s unload ratio is lower than critical unload ratio, rebound deformation doesn’t happen; when ooze’s unload ratio is higher than critical unload ratio, rebound deformation will happen. The ooze’s deformation after unloading is divided into primary rebound; secondary rebound and appending secondary consolidation deformation. The essential of appending secondary consolidation deformation is creeping of soil framework.

On the basis of mechanical conditions and geological circumstances of rockburst, the single state variable model is introduced to describe the dynamics characteristic and evolvement characteristic of rockburst. The research shows that the parameters K and greatly affected the dynamics characteristic and evolvement characteristic of rockburst; and , f contributed a little to the model. This model well simulated the stick-slip characteristic and the process of failure in rockburst system which explained the mechanism of rockburst and provided the theoretical foundation to forecast rockburst.

Field experience and similar material simulation indicate that there is the bending catastrophe phenomenon of anchor roof beam in bolting roadway sometimes. By means of mechanical model analysis, bending catastrophe steady mechanism and equilibrium conditions of anchor roof beam are systematically studied; and the bearing area and horizontal thrust of the anchor roof beam are analyzed, too. It is discovered that anchor roof beam different steady characteristics and different dynamic equilibriums in different stages. The theoretical and engineering value of them are prospected for the presentation and controlling of anchor roof beams.

The observating and theoretically analyzing inner force and displacement of the supporting structure for foundation pit are carried out. There are different losses of prestresses of anchors mostly about 10 %—25 %; and increase of inner axial force of anchors about 10 % during the construction. The inner axial force of steel props increases with the increment of the excavation depth; and its value changes with the varieties of excavation mode, velocity and dismantlement of the underlying props in order. The horizontal displacement of the retaining pile body is related to the pile depth and supporting condition. The deformation of the earth surface is the largest in the middle and the smaller at the end. The calculating data are generally accordant with the measuring data; but there are some differences between them because of the influences of various factors and the dynamic construction.

In order to improve the deep ground, especially heterogeneous block ground of mountain area and rock filling out the sea, high energy level dynamic compaction (HELDC) is necessary to strengthen the ground. The HELDC is mainly used in the production facilities and high-capacity oil tank of petrochemical project, so as to eliminate the collapsibility of loess and treat the non-uniformly stone backfill foundation of mountain area and coast. The succeed experiences of ground treatment using HELDC of 4 oil tanks (50 000 m3) foundation in Qingdao Zhongjiao Asphalt Co. Ltd are described in detail. Finally, some referable conclusions are obtained.

Terzaghi's one-dimensional consolidation theory is modified by considering seepage force, the consolidation equations under both upward and downward seepage are derived and the distribution of the seepage stress during consolidation is also analyzed.It is concluded that the seepage force affects on the consolidation degree obviously, especially when Tv is about 0.1, the values of the consolidation degree considering the seepage force or not will have the difference of 30 %. The author believes that the seepage force cannot be neglected.

The design and construction situations of A14 testing section soft soil roadbed on Qinhuangdao-Shenyang passenger transport special railway line are introduced. The subsidence data are observed in the testing sections what were treated through different groundwork treatment measures. The soft soil roadbed subsidence feature is discussed; and the subsidence data and subsidence rate after engineering works are predicted in the roadbed after consolidation treatment according to test data. The relationship between soft soil groundwork treatment measures and subsidences is also analyzed. The researching results indicate: the soft soil roadbed subsidence is affected by the added load very much; the subsidence amount of soft soil roadbed what is treated with gravel piles or lime injected piles is less than other methods of treatment; it is not a key that the rate of filling soil is controlled in the loose and soft soil roadbed.

Constructing metro tunnel in shallow stratum destroys stratum structure, so stratum stress is freed and corresponding deformation is generated. By in-suit observation and regressive analysis together about deep stratum displacement of Shenzhen metro PhaseⅠProject Guomao-Laojie section tunnel cross-section, which caused by shallow tunnel construction method(STCM) construction in weak watery stratum of Shenzhen. basic movement regulations of stratum above tunnel, are achieved. Subsequently, corresponding technologic measures of how to control large deformation in stratum are advanced and fully applied to the late phase construction of Shenzhen metro PhaseⅠProject. Good effects are achieved in guiding tunnel construction.

In order to reduce the quantity of the unused steel-slag and take full advantage of their useful values in pile foundation, the research is conducted on the confecting method of steel-slag concrete. Through comparison of the physical and mechanical properties between steel-slag concrete and plain concrete, we can analyze the advantages of using steel-slag concrete. Based on the test, an empirical formula is developed, which provides some bases for practical projects. The mechanical properties of steel-slag concrete prevail over that of the plain concrete; also the quantities of cement and gravel are reduced, consequently reducing the capital cost of the project materials; so this method is economically and safely to use and it can solve the environmental problems of unused steel-slag.

Many uncertainties caused unavoidable risk in engineering planning and engineering decision. The paper shows how to calculate the risk rate through reliability index, and provides decision-making method based on reliability theory. Two examples are given in the paper. As example one a retaining wall design is performed to show the method’s efficiency and practicality. How to choose the best case between aqueduct and tunnel in South-North Water Transfer Project of Middle Route is explained in example two and the simple decision mode is described.

During the analysis of cross-section forces of shield lining, the project must be checked by the method of the most unfavorable combination of the loads and it is doubtless to increase the workload of the designers. In light of the condition, an analytical method considering load combination is put forward. First, the structural analysis model of shield tunnel lining is established and different kinds of loads are classified on the basis of construction process and combined according to the design code for different working cases. Finally, the internal force envelope diagram is acquired. In the meantime, the computation program is accomplished and used in a project.

The gravity induced preconsolidation deformation of rock and soil has been finished before our consideration in many geotechnical problems. The stress field in soil mass is balanced with the gravity field. So in the FEM calculation that is based on the initial condition above, if the gravity is loaded directly, a rather big deformation will occur which should have been finished. So on the basis of initial stress load theory that is studied in this paper, an approach is proposed to exclude the preconsolidation deformation. The detailed procedure is provided by example at last and proved to be true.

By diagnosing the slope excavation diseases during the highway construction in Sichuan basin, the main distortions and failure types of slopes in approximate level red beds are concluded, that is accumulation formation landslide, bedding landslide, rip distortion of rock mass and rock mass collapse. The main geological character of slope in approximate level red beds is summed up; the three phases of slope distortion and failure, that is excavation load-off distortion, developing and widening of steep joint, distortion and failure come into being, are put forward; Finally, the failure mechanism is analyzed combined a project example.

The load bearing behavior of post-grouted bored piles were analyzed deeply, according to the static load test and stress testing results of test piles in a building and its nearby site. The top load-settlement relationships of post-grouted bored piles can be represented with power models; those of un-grouted bored piles can be represented with hyperbolic models. The ratios of base bearing ranges over 6.4 %—18.4 % after grouting, and the ratio increased sharply with the increasing of top loads. According to the extrapolated values, the ultimate load bearing capacities of piles grouted in the base or the shaft were increased 89.85 %—147.81 %, those grouted only in the base were increased 30.08 %—81.78 %. According to the results of gray relational analysis, the total grout quantity is the most important factor no matter which grouting method is applied, and the effect of base grouting is better than that of shaft grouting.

The structure and permeability of rock determine directly the stability and security of buildings’ surrounding rock. Using hydraulic fracturing tests, the structure and permeability of rock will be shown under high water pressure. On the basis of the hydraulic fracturing tests at the dam site rock of a certain hydropower project, the change and law of the rock’s structure and permeability are analyzed and the mechanism which forms fracture in rock is explained during the hydraulic fracturing.

Foam lightweight material is a new material applied to geotechnical engineering. By using uniform design methods, mix proportion test for the material is conducted. Through multi-element nonlinear regression model, primary effect of test factor and alternate effect between factors are analyzed; and a nonlinear programming question with constraint is established. So the optimum mix proportion satisfying engineering requirements is obtained by optimum method.

Rock sample has random and fuzzy characteristics, the traditional statistic method isn’t suitable for processing fuzzy attribute. The paper analyses the rock mechanical parameters in slope engineering using random-fuzzy method and discusses the choice of membership function. The practical computation results show that the random-fuzzy method is more realistic and better than conventional methods.

Considering tunnel construction steps, contact surface between segments and soil and stress releasing, 3D-FEM is put forward to simulate shield tunnel construction and analyze the earth deformation caused by tunnel construction. The computation results are satisfied compared with the practical measurements; and the ideas and methods in the paper can provide valuable reference for researches on earth deformation and even for tunnel construction management.

Based on the theory of soil dynamics and using FEM, the stress-strain relations under different ground conditions and different tamping means are studied. Compared with test results in situ, the choice of tamping factors including hammer weight, tamping height and tamping interval etc., is established theoretically. In case of foundation and road embankment material parameter, valid reinforce range results is 1.5—2.5 of hammer's diameter. This conclusion are used for engineering practice.

The limit state for settlement of expansive soil roadbed isn’t so absolutely definite as “critical point” since those factors, such as water content, void ratio and consolidation degree, are unstable and stochastic. Basing on the fuzzy mathematics theory, the paper prescribes the limit state as an incertitude section closing by “zero” when analyzing the reliability of expansive soil roadbed, introduces “fuzzy critical section” and “fuzzy limit state”, brings forward the conception “fuzzy reliability”, and expounds the method and processes for analyzing fuzzy reliability of expansive soil roadbed. Furthermore, the paper takes a typical expansive soil roadbed as example to calculate the fuzzy reliability of settlement. The result indicates that the fuzzy invalidation probability of exceeding allowable settlement may be a little big when expansive soil roadbed is designed according to intensity and stability principle.

We can look the stratum movement and subsidence as a whole system to study. The common nature of stratum movement and the development procedure of crack arch are described. Meanwhile, based on the ground observation by the global positioning system (GPS), the boundary angle and the motion angle, which aim at special geologic conditions, are determined. The relation between the position of underground working face and ground subsidence velocity are found.