Combined with high pressure permeability test, conventional pressure permeability test and indoor permeability test for fractured rock mass of high pressure water tunnel in one water-pumped storage power project, the variation law of rock mass permeability under high water pressure is analyzed to describe the relation between discharge and water pressure. Through the calculation of permeability coefficient of fractured rock mass, relation between water pressure and permeability coefficient is also discussed. By comparing the results of high pressure permeability test, conventional pressure permeability test and indoor permeability test, the environmental stress and water pressure state of rock mass are considered as the main factors influencing the permeability coefficient. The test results indicate that the permeability coefficients in high water pressure are obviously greater than ones in low water pressure state. It is also pointed out that the permeability coefficients in indoor test are greater than ones obtained from in situ test.

Loading and unloading triaxial tests for coal samples under various confining pressures are conducted. The tests show that when the confining pressure is relatively low, the loading and unloading loci are almost coincident. The coal samples show the characteristics of linear elasticity and brittle failure. While under the relatively higher confining pressures, the stress-strain curve is nonlinear, and the unloading path does not come back along the loading locus any more. Moreover, the residual deformation appears, this shows the plastic characteristics of the coal so as to describe the hardening plasticity quantitatively; a new computing method for the hardening parameter based on its geometric meaning is presented in principal strain space. The accumulated plastic strain is chosen and computed with the test data of 27 MPa confining pressure. This hardening parameter increases with the increase of axial strain, the hardening parameter value computed with this method is higher than that of another traditional method. But the method presented is more rational.

Based on UH model for overconsolidated (OC) clays and the concept of asymptotic state, an asymptotic state constitutive model for saturated sand is developed to be an asymptotic state constitutive model for overconsolidated clays to describe the overconsolidated and asymptotic state behaviors of clays. The proposed model can be applied conveniently to three-dimensional stress states by using transformed stress method. Compared with Cam-clay model, the proposed model is simple, and it only requires one additional soil parameter which is the slope of the Hvorslev envelope. The model can model many characteristics of clays well, including strain hardening and softening, critical state, stress dilatancy, path dependency, and asymptotic state behaviour.

A field experiment of high energy dynamic compaction (HEDC) with 15 000 kN•m was carried out on a rubble fills site underlain by soft interlayer along coastal area for the first time in China. The ground settlements of drop points and their surrounding areas during a single drop DC are monitored, the dynamic penetration test (DPT) is carried out before and after HEDC. The test results are comprehensively analyzed, and the comparative studies are systematically done. Furthermore, the reinforcement mechanism of HEDC is discussed on a rubble fills site underlain by soft interlayer underlain, and some conclusions such as effective depth of improvement (EDI) on rubble fills site with 15 000 kN•m HEDC are drawn. It is recommended that the EDI should be 11.5 m, the intervals of 12.5 m between main drop points, and the drop numbers of 18-22 are suitable for a rubble fills foundation underlain by soft interlayer.

The mechanical behaviors of rock mass containing discontinuous joints under direct shear condition and the mechanical theory are analyzed; Lajtai’s tension failure theory of rock bridge is modified. It is proposed that the tension failure in rock bridge weakens the mechanical behavior after analyzing the stress state of rock bridge. The region of the weakened mechanical behavior is also pointed out. According to its failure process, the failure models of rock mass containing discontinuous joints are suggested. The modified failure theory of rock bridge and suggested failure models are verified through direct shear test.

Subgrade surface settlement is a basic content of deformation observation and settlement assessment for railway passenger dedicated line; but the application of observation accomplishment has some falsehood because of insufficient understanding of the physical meaning and engineering significance of subgrade surface settlements. With a large number of settlement observation data of subgrade in Wuhan-Guangzhou railway passenger dedicated line, the settlement characteristics and symbolical meanings of subgrade surface are analyzed; and the reasonable application method of the observation accomplishment is discussed. The analysis shows that the settlement observation data of subgrade surface may be used to investigate the stability and the developing tendency of subgrade settlement, and whether the correlation coefficient of curve regression meets the requirement, however, that it cannot be used to calculate post-construction settlement. A calculating method for post-construction settlement is suggested by combining the measured data of subgrade surface settlement and ground settlement.

Traditional main solidified materials (cement) and auxiliary materials (fly ash and gypsum) are used for solidifying sludge of East Lake of Wuhan. Based on the results of unconfined compressive strength test and triaxial shear test, the strength and characteristics of sludge solidified by the combination of different materials and mixture ratios are determined. Experimental results show that the role of cement is the dominant additive during solidification of sludge. The role of fly ash is equivalent to reducing the initial water content of sludge, and the early strength of solidified silt has been increased rapidly. The gypsum is conducive to the early strength formation of solidified sludge; and its role is shown throughout the solidifying process continuously. The model of stress-strain curve has been transitioned gradually from strain softening to strain hardening with the increase of water content of sludge samples which are solidified by cement only. Also the effect of the changing confining pressure on strength of solidified silt has been weakened gradually with the increasing water content. The model of stress-strain curve has been transitioned from strain softening to strain hardening because of adding auxiliary solidified material to sludge. The 20% cement, fly ash for 3 times the cement volume, and gypsum for 30% of the cement volume are the optimum mixture ratio for different water content sludge of East Lake. The research results will be contributed to the sediments treatment of East Lake as well as the foundation treatment and environmental renovation of the sludge stock yard.

A new optimization approach for reliability analysis proposed by Low & Tang is introduced and applied to slope reliability analysis. The optimization approach has many advantages: it is applicable to correlated variables with any probability distributions; it need not compute the equivalent normal means and standard deviations and independence transform of correlated variables. It can obtain the minimum reliability index and the probabilistic critical slip surface within the original variable space, and it is very simple to implement with any appropriate optimization method. Two slip surfaces are often used in slope reliability analysis: the deterministic critical slip surface of the minimum factor of safety at mean variable and the probabilistic critical slip surface of the minimum reliability index. However, there are circumstances where the two slip surfaces are quite different. A simple method proposed by Hassan & Wolff to obtain the probabilistic one seems questionable due to its simplicity. The results of example slope reliability analysis show that the probabilistic critical slip surface obtained by optimization approach is quite close to that obtained by Hassan & Wolff’s simplified method, which shows that the simplified method is efficient and can be used in practice.

A series of dynamic behavior tests on Nanjing fine sand with flake-shaped structure are performed by using WFI cyclic triaxial apparatus made in England. The dynamic behaviors of Nanjing fine sand with flake-shaped structure under different static deviator stresses and cyclic stress ratios are studied. Through comparing the effective stress path under cyclic loading with static loading, the process of liquefaction of saturated flake-shaped structural Nangjing fine sand with the development of pore-water pressure, including initial compact state, compression state and dilative state, are investigated. In addition, according to different combinations of static deviator stresses and cyclic stresses, two kinds of failure patterns with deviator stress reversal or without deviator stress reversal are observed including cyclic mobility and failure of accumulation residual strain; and the mechanism of the cyclic mobility is investigated preliminarily.

The strength parameters are obtained with consideration of influence of wetting and drying cycles by an experiment based on laboratory direct shear test. The test basically reflects the phenomenon of crack evolution with wetting and drying cycles and reveals that crack evolution results in strength degradation. The results show that both cohesion and internal friction angle will attenuate along with crack evolution. Comparatively, cohesion index will be affected more obviously by crack and its determination should be more cautious. The law of attenuation accords with hyperbola; and the empirical expressions are proposed, which show that the relationship between attenuation of shear strength with increase of wetting and drying times is in fact with crack evolution. The expansive soil in engineering practice includes all kinds of cracks; therefore, in the design, the selection of strength parameters should consider the crack in the expansive soils. As the same time, the test method proposed makes the research of influence of crack evolution on the strength characteristics relatively simple and feasible.

A newly developed seepage consolidation odometer is designed to investigate the suction discipline of soft clay under unloading after rebound deformation. Taking saturated soft clay as a study object, the suction characteristics of soft clay with the developed seepage consolidation odometer are analyzed. Test results show that the new odometer apparatus designed and manufactured which improves scalability can collects the water discharged from the soft clay when the consolidation happens; when the unloading ratio is greater than critical unloading ratio, the soft clay specimen rebounds and absorbs water, and its characteristics are related to the preloading duration. The volume change of the clay specimen is equal to the volume of water that enters into the soil when the unloading happens at the end of primary consolidation. When the preloading duration is 24 hours, the soft specimen’s rebound deformation is divided into two stages that include primary rebound and secondary rebound. During the primary rebound stage, volume change of the clay specimen with rebound deformation is equal to the volume of water that enters into the soil; during the secondary rebound stage, the specimen has small deformation but doesn’t absorb water. The ratio of the volume of water absorbed by soil-to-the volume of water drained by consolidation is less then 10% generally.

By using of the experimental system of advanced MTS and INSTRON rigid servo-controlled testing machine, the destructive energy dissipation test under routine triaxial compression, dynamic and static unconfined uniaxial compression condition of backfills with different cement-sand ratios in the special large-sized stope were made; all kinds of correlative mechanical parameters, full curves of load-displacement and stress-strain were obtained after test. According to the obtained mechanical testing data and the characters of compression experimentation, taking the destructive energy dissipation of single specimen, unit volume, unit weight as check indexes, the different energy dissipation parameters under complicated compression stress conditions of backfill are calculated; the change rules of destructive energy dissipation are analyzed; and the function connection under different loading conditions after statistic regress is set up. It has definite realism meaning to ore pillar mining with safety, maintenance roof’s stabilization of stope and tunnel, geostatic control, prevent ground sink, environment protection so as to break a new path to use the viewpoint of energy dissipation to analyze and study destruction of backfill, which are of a certain instructive importance to mine improving the quality of backfill, including other concrete engineering fields.

For soft clayey soil in Shanghai, the relationship among the strength of stabilized soils, cement contents, initial pH value and curing time is investigated experimentally. The strength obtaining mechanism of cement mixed clayey soil of Shanghai with curing time, cement contents and initial pH value is presented at first. Then, the strength obtaining mechanism of some typical Japanese clay compared with Shanghai clay is discussed. Limited laboratory test studies show that the strength obtaining of Shanghai clay is abruptly increased with the cement content larger than 17%-20% or the pH value is larger than a critical value(pHc) immediately after mixing. For Shanghai clayey soils, the critical value pHc is 11.7. If the cement content is higher, it will take a long time for the strength of cement mixed Shanghai clayey soils to reach a steady value. This phenomenon is much different from that of cement mixed Japanese clay, of which strength is gradually obtained with the cement content.

The soil resilient modulus is an important parameter in the pavement structure design. It influences directly on safety and economy of the pavement structure. The indoor vibratory compaction is a new method of forming specimen, which can simulate the properties of vibratory compaction in the real road construction. The relationship between the resilient modulus of compacted loess and its physical indexes such as dry density, water content, consistency and compaction degree and age is analyzed.Therefore, the resilient modulus of vibratory compacted loess is compared with that of the heavy rammer loess. The results show that the correlative relations are presented between resilient modulus of compacted loess and those physical indexes mentioned above. The resilient modulus of indoor vibratory compacted loess is larger than that of indoor heavy rammer loess under the recommended parameters’ condition.

Pile foundation, as a type of important foundations, is applied to the engineering widely. For the important project, horizontal loading capacity, internal force and distortion should be determined through horizontal loading test. The method which is used to measure and compute moment, yield and turning angle by steel bar gauge is introduced in detail. According to the measuring results, the horizontal critical load of the testing pile is 120 kN. The steel bar gauge measuring results show that the largest moment is located in the depth from 2 m to 3 m under the horizontal load, it transfers to the deeper location with the increase of the horizontal load, and the bend distortion only occurs in the upper of 1/3 pile length.

It’s the basis for designing subgrade bed to master detailedly dynamic performance and settlement laws of subgrade. Combining with the construction of Dazhou-Chengdu railway, the studying team buried test elements in subgrade and studied the dynamic performance and settlement laws of subgrade by using a new facility called ZSS50 which could simulate the train dynamic loads. The results indicate that the dynamic indexes and settlements meet the designing requirements; and an evident influencing factor for them is the axle load of train; along the cross section of subgrade, the dynamic responses are unequal, and show the saddle-shaped distribution; the dynamic responses decrease with the depth of subgrade increasing, and decrease faster in surface layer than in bottom layer; the ZSS50 can model exactly dynamic loads of train, it can be handled easily; and it is an ideal facility for studying the dynamic performance of track and subgrade.

Thixotropic research on wetland soft soil in Cuihu is carried out by manual vane-shear apparatus. The change of sample’s shear strengths resulted from different stewing times is observed, which can determine the recovery time and recovery degree of shear strength, sensitivity and thixotropic strength ratio. The thixotropy of wetland soil is studied at three depths of soil, which can obtain the coupling effect of depth and stewing time on recovery of soil shear strength. Remoulded samples are studied by different moisture contents tests. The curves of moisture content and shear strength are gained. Test results may provide reference for further study of engineering properties and proper development of wetland soft soil

Using the freeze-thaw cycle apparatus combined with electrical resistivity observation for whole process , repeated freeze-thaw tests in a closed system(i.e. no water supplied) are performed for the saturated silty clay in Beilu River with dry density of 1.62 g/cm3, in which the complete testing data for the deformation versus time curve, temperatures in different layers and the associated electrical resistivity-time curve are obtained. The experimental results indicate that the changes of resistivity, temperature and deformation during freeze-thaw cycles are real-time and synchronical, which also proves that it is feasible to study the change of soil structure during freezing and thawing by using electrical resistivity method. The resistivity of frozen soil decreases and that of thawed soil increases exponentially with increasing of freezing-thawing times. The amount of frost heave, thaw collapse and average dry density in every cycle rise with increasing of freezing-thawing times, and they trend to be stable after 5 freeze-thaw cycles.

The effective stress will vary with pore pressure in reservoir rocks, which then will induce the change of permeability and the stress sensitivity to permeability. Laboratory study of the stress sensitivity to permeability has been carried out. Experiments include aging treatment and four cycles. Each cycle is run under constant-confining-stress through decreasing and increasing pore pressure. Experimental data are collected with steady-state method. The results show that permeability varies with pore pressure. At low confining stress, the variation range of permeability is larger, while at high confining stress, it is smaller. For equivalent net stress in different cycles, permeability is different. The change of permeability, with the change of pore pressure at some cycles, belongs to a typical step change. Meanwhile, the effective stress coefficients for permeability are calculated by Bernabe’ model. The calculated results，according to Benabe’s viewpoint, show that the step change of permeability is resulted from the change of microcrack deformation with stress change. The stress sensitivity evaluation to permeability has done; and the results show that the tight sandstone reservoir studied puts up the moderate stress sensitivity.

According to the current situation of pile foundation engineering, a model test equipment is designed to study the bearing and deformation characteristics of steel pipe piles in calcareous sands, which are taken from Yongshu reef in Nansha Islands in South China Sea. In contrast to the tests with silica sands, it is shown that calcareous sands behave in a completely different manner than silica sands. For sands having the same relative density, the ultimate bearing capacity in calcareous sands is only 66-70% of that in silica sands, the axial force has a slow decay rate, and the ultimate shaft friction of open-ended piles is less than that of close-ended piles in calcareous sands, nonetheless, it is only 20-27% of that in silica sands. In addition, shaft friction is very sensitive to density in silica sands but less so in calcareous sands. It is found that the reduction in lateral pressures on the pile shaft, which is caused by grain crushing under the high stress levels produced during pile driving, is the main reason for low shaft friction of steel pipe piles in calcareous sands.

An experimental study is performed to improve the high liquid limit soil to fill the roadbed of Yongan-Ninghua expressway. Firstly, some important factors influencing the experiment results are found out; and the corresponding countermeasures are established. Then a number of laboratorial experiments are carried out to obtain the optimal proportion of gravel for different high liquid limit soils. The study contributes to the rational use of high liquid limit soil and provides reference to the design and construction of similar engineering.

In engineering practice, the subsoil with vertical drains is often composed of multi-layer strata, and the subsoil is partially penetrated by vertical drain wells. Based on basic hypotheses of Terzaghi’s one-dimensional consolidation theory and Barron’s consolidation theory, a simplified consolidation calculation method for the layered ground with vertical drains is presented. By connecting the pore pressure with deformation, the consolidation degree and the ground settlement with vertical drains can be predicted. In addition, some key problems in the process of the calculation are analyzed, such as the inverse analysis of the consolidation coefficient, the consolidation calculation when the drain wells partially penetrate the subsoil, the selection of thickness of the compressive soils, and so on. The consolidation procedure CONSOL via FORTRAN language is compiled. And it is verified that the method is applicable to engineering practice.

Based on the limit equilibrium theory, assuming that the limit equilibrium conditions of the slip wedges with respect to the all depths behind a convex-arc wall can synchronously be satisfied, as well as befittingly considering the effect of the normal stresses on the two sides of per slip wedge with respect to per depth; an improved computational method that can be used to calculate the distribution of the granular material pressure on the convex-arc wall with increasing depth is proposed. The computational method can present the nonlinear distributional characteristic of the granular material pressure, and can also predict that ignoring the normal stresses on the two sides of per slip wedge with respect to per depth will result in a lower calculated pressure distribution compared with the measured pressure data, which is proved to be correct via comparing the theoretic pressure curve with the measured pressure data; moreover, the theoretic pressure curve can agree well with the test data as it is considered correctly in calculation that the effect of the normal stresses on the two sides of per slip wedge with respect to per depth.

The construction mode at the joint between steel lined reinforced concrete penstock on downstream surface of dam is summarized; and the failure mechanisms of the joint are analyzed. Two types of failure modes, shear failure along joint and tension failure perpendicular to joint, are indicated to be the main failure modes under high-intensity earthquake. Based on limit state method, expressions corresponding to the failure modes are established, which can be used to evaluate joint safety. An example is given for interpreting usage of the expressions, which shows that there exists an unfavorable combination stress state in the joint under high-intensity earthquake; and the joint can be safety when employing stepped keyslot and proper quantities of anchor bar.

Landslide disaster which should be considered as a nonlinear dynamic system has strong spatial variation and randomness. Using the transmission coefficient method at different safety factors, the slip soil of Dagouwan Landslide is analyzed inversely; and the relationship between shear strength parameters on conditions of critical state and limited water level is obtained. Analyzing the shear strength parameters gotten by shear tests and combining engineering geology analogy, the distribution of shear strength parameters is obtained by statistic method; then the stochastic shear strength parameter is generated. Supposing Mohr-Coulomb criterion obeys linear distribution in the range of slide mass gravity stress, with the ? -? distribution curve cluster gotten from shear test, taking the range of slide mass gravity stress into account, the c-? envelope polygon is obtained. With the envelope polygon, the effective stochastic shear parameters are selected. After Monte Carlo simulation, the failure ratio of the landslides at different safety factors are calculated based on the distribution relationship between effective stochastic shear parameters and the limit equilibrium c-? curves gotten by the inverse analysis. The prediction shows the stability of Dagouwan landslide is very weak at limit water level. Combining the twice field survey on Dagouwan landslide in the process of water impoundment, the results are identical.

The monitoring data of dam settlement are usually disturbed by uncertain factors and meteorological factors such as temperature, air humidity and light intensity. In order to remove those factors, a new method of wavelet analysis considering the effects of meteorological factors for dam settlement is proposed. Firstly, the functional relation between the monitoring data and the meteorological factors is established. And then based on the functional relation, the effects of meteorological factors on the monitoring data of dam settlement can be removed. Finally, based on the de-noising process of monitoring data by wavelet analysis, a dam settlement curve that is close to the practical situation can be obtained, which can provide dam stability evaluation with scientific basis. The results show that the new method of wavelet analysis considering the effects of meteorological factors is better than the method of direct wavelet analysis; and it can effectively remove noise signal caused by meteorological factors and other uncertain factors; and the dam settlement processed in this method agrees well with the numerical simulation results; and it has better feasibility and practical application value.

Acoustic emission (AE), which is produced with the load increasing, is a ubiquitous phenomenon associated with brittle fracture in many brittle materials such as rock .AE technique is better than other methods in researching failure of brittle materials. AE is tested in rock specimen under loading and breakage, and the signal of AE is recorded. Action laws of AE in rocks are studied by using chaotic kinetics. According to the recorded experimental data, the correlation dimension and the maximum Lyapunov exponents are calculated. It is shown from numerical results that the loading and failure process of rock possesses chaotic characteristics. Based on the theory of phase space reconstruction, it is well revealed their kinetic characteristics during the failure process. It is a basis for applying chaos theory to research rock acoustic emission.

The Gaussian process (GP) is a high and new machine learning way developed rapidly in recent years. It embodies the characteristics of programming easily, self-adaptive acquisition of hyper-parameters and prediction with probability interpretation which are superior to those of SVM. Aiming at the slope angle design influenced by many factors in slope engineering, the Gaussian process with the combinatorial kernel function obtained by combination of squared exponential and rational quadratic covariance function is implemented by learning machine routine in Matlab for overcoming poor predictive precision and network generalization ability of single kernel function. Then the automatic relevant determination (ARD) is introduced into combinatorial Gaussian kernel function in the programme and a GP regression model with regard to hyper-parameters is established; meanwhile the correlation and characteristics selection about inputs and prediction for testing samples on the basis of the net are completed respectively. The results show that compared with support vector regression method, the prediction precision of GP is not only slightly better about all error indexes; and the prediction results reflect well uniformity of predictive precision and dispersion between predictive value and measured value, but also the physical meaning of ARD parameters are distinct; so it can be served as a new tool in slope angle design.

60 points of in-situ rock stresses have been measured in 13 coal mines of Lu’an coal mine area by means of hydrofracturing stress measurement rig with small borehole. The stress measurement data point out that: the maximum horizontal principal stresses on 55% of the total measuring points are greater than the vertical stresses in Lu’an coal mine area; and the in-situ stress values exist great differences in various mines because of different buried depths and geological structures. However, the magnitude of the stresses is generally moderate value. The orientations of the maximum horizontal principal stresses change greatly from southern part to northern part, the tectonic stress fields present changeable state. Based on the field data, the stress distribution map of Lu’an coal mine area was drawn up; the stress variation with buried depth, and the relation between the specific value of the mean horizontal principal stresses to the vertical stresses and buried depth were analysed. The stress measurement results provide reliable fundamental parameters for engineering practices, such as mine field development, roadway layout and support design, and improve the scientific degree, rationality and reliability of engineering designs.

House cracking and over-deforming are common risks when tunnel crossing urban territory; and relative studies of house cracking calculation and its risk evaluation lag far behind engineering need. By comparison and analysis, it is verified by uniaxial and triaxial compression tests that disturbed state concept (DSC) can give good description of material behavior after cracking, and combining this model with the practice of Xiamen airport road tunnel undercrossing building blocks, houses’ deforming and cracking will be quantitatively calculated and evaluated; and the results have good accordance with in-situ house cracks and deformation monitored data. Meanwhile, it still shows close correlation between DSC disturbed factor and house cracking, thereby from mechanics, it is effective and reasonable to depict house cracking by using disturbed factor. Furthermore, process control criteria of house deforming and cracking can be set up by DSC model. Finally, in each key step and stage of tunnel undercrossing building blocks, house deforming and cracking risks can have criteria to go by and be process-evaluated and controlled well.

With thoroughly analyzing the load transfer mechanism of CFG pile composite foundation, considering the characteristics of the interaction among pile, soil and bedding course, according to the assumption and the simplified distribution mode about the vertical displacement of pile-soil element, an elastoplastic load transfer model is introduced; and considering both upward and downward penetration displacements of piles, an basic differential equation of settlement calculation of CFG pile composite foundation is established based on load transfer method. Then, a new method for calculating the settlement of CFG pile composite foundation is developed. This new method is applied to analyzing an experiment; and the results show that the calculated results are consistent with the real values. This method can decrease the cost of calculation and can be conveniently applied to the practical engineering.

Laterite soil is one of the typical and special soil. There are clearly states in the technical specification of highway subgrades that the compaction degree can be reduced according to the specific condition when the subgrade constructs with special fillings. Moreover, the subgrade can’t be filled directly with high liquid limit and high plastic index soils. By using the laterite of one highway, a series of compaction and California bearing ratio (CBR) tests are carried out; the results indicate that laterite is sensitive to water strongly; the water content corresponding to the maximum CBR is 3 % greater than the optimal one. In addition, according to the rules that strength, compressibility, swelling-shrinkage, permeability indexes change with compaction degree, the compaction degree of laterite which is as sub-embankment filling can be reduced by 2.5 %, the water content is around 35 % during compaction.

"5.12" Wenchuan earthquake induced a large number of landslides, which had directly threaded human lives and property safety. But at the same time, it also provided valuable material to study the impact of earthquakes on the landslide. Taking Wangyuezhai landslide instantiated in Li city of Sichuan Province for example, on the basis of exhaustively mastering the basic characteristics of landslide before and after Wenchuan earthquake, stability and stress-strain features were then calculated and analyzed by limiting equilibrium method and finite difference method, which could analyze landslide’s deformation features from the respect of stress-strain. The analytical results are consistent with the macro-geological phenomena before and after the earthquake. These results provide a reliable basis for the future study of the impact of earthquakes on the landslide and geohazard prevention & geoenvironment protection.

Push shear tests have often been used to determine shear strength of rocks or soils in investigation of landslides. However current analytical methods for a push shear test recommended in Handbook of Engineering Geology could not adequately derive parameters of the shear strength and should be improved. Data processing method is presented for the push shear test without normal loading based on the assumption of model’s rigid body and no constraints along Y axis. A differential equation is established to represent the push shear test; and a set of equations is then derived for solving cohesion c, friction angle ? and curves of the shear failure surface. A case study is used to examine new formulas developed. Based on observed compression phenomena during in-situ test, the localized initial failure near the compression surface is analyzed. Causes for variation of the shear failure surface are explained. It is required that no constraints are applied to the compression surface along Y axis. In addition, the compression surface should be oriented perpendicular to the sliding or rotating surface. At the end, several issues related to push shear test are also discussed.

New-built railway passenger dedicated line from Zhengzhou to Xi’an passes through many districts mostly covered with loess. It’s the first time for China to build such large cross-section tunnel groups in loess zone, which have an area of more than 170 m2 and a span of more than 15.1m. Design theory and relative experience about this type of tunnel in the loess zone is insufficient, especially the anchoring effect and mechanism of systematic rockbolt is unknown. That is a key problem for the large span loess tunnel design. To analyze the effect of systematic rockbolt in the loess tunnel, a formula to explain systematic rockbolt anchoring mechanism is deduced; and the key cause of rockbolt loading in loess tunnel is pointed out. A theoretical model is used to study rockbolt loading; and the calculated results are in good agreement with practical measured data; it is indicated that the theoretical model proposed can give right loading of rockbolt. These results show that in the shallow buried loess tunnel, anchoring effect of systematic rockbolt near the arch is very weak, but systematic rockbolt near the sidewall works well.

An experiment of the explosion wave propagation in saturated soils is accomplished in the ? 2.5×5 m pothole. Measured pressure waveforms in different burial depths are gained in the saturated soils. The loads of the shock wave and the elastic wave are measured in the experiment. The boundary is obviously different between the shock wave and the elastic wave. A comprehensive analysis shows that the saturated soil has the nature of liquid-dynamic area appearing and the shock wave forming when the blast wave spreads in saturated soils. The bilinear progressively increasing-hardening constitutive relation in saturated soils is established. Dividing pressure is determined when the shock wave changes into the elastic wave.

On the basis of subroutine UMAT provided by ABAQUS，the Duncan nonlinear elastic model for static analysis and the equivalent linear model for dynamic analysis are implemented; so the database of constitutive model in ABAQUS is enlarged. The methods to model layered construction of dam, correct the displacement of new fill layer, consider the effect of wetting effect, evaluate liquefaction resistance of dam material and compute the permanent displacement induced by earthquake are described in detail. The results of examples are found to be reasonable and reliable, it verifies that ABAQUS can be used in static and dynamic analyses of earth-rockfill dam after the secondary development. The present method can make use of the advantages of ABAQUS, such as convenient preprocessor and postprocessor, high solution precision and high ability to handle complex problems; so an alternative method for static and dynamic analyses of earth-rockfill dam is provided.

Composite stiffness principle with biparameter method applied to reasonable calculation of piles subjected to laterally concentrated loads on the top of piles brought forward by Wu Heng-li, is extended to be applied to retaining structures of deep foundation pits subjected to laterally distributed loads (earth pressure). Numerical method of link finite elements is brought forward. Then an engineering example of the construction process of excavation and retaining structures of a deep foundation pit with internal braces is simulated. Reasonable wall-soil composite stiffness and subgrade reaction biparameter are back-analyzed by displacement measurements. Compared with the existing methods, the results obtained by this method are closer to the measurements. So it is shown that numerical solutions of link finite elements based on composite stiffness and biparameter method can be more reliable to calculate retaining structures of deep foundation pits with internal braces; and it has the reference value for applications.

The design tensile and prestressing force calculation method of anti-slides pile with prestressed cables are summarized and improved, which makes the methods consider displacement coordination of pestressed cable and pile. According to each case of prestressed cable acting on pile top and pile body, the semi-analytic and semi-numerical weighted residual method is applied to stress calculation of anti-slides pile with prestressed cables; and the extensively adapted B-spline function is used as trial function; then the calculation program is worked out; and the program can consider soil resistance above sliding surface in front of pile. The program is applied to analyze existing example; and its result is compared with the result obtained by finite difference method; the reliability of the method is proved. Simultaneously, the proposed method is applied to another two calculation examples; aiming at different calculation methods of anchor design tensible and prestressing force, the comparative analysis table with relevant design tensible force, prestressing force, maximum bending moment of pile body and pile top displacement is presented respectively; pile force diagram is given; and the calculation also shows that it is not every method suitable for specific calculation example; and it must take concrete analysis of concrete issue.

Based on the effective stress theory of a single variable of unsaturated soil, unsaturated water-gas fluid-solid coupling equations are established. The railway K240+10-70 from Dazhou to Chengdu, Sichuan, is damaged caused by rainfall considering runoff-underground seepage and fluid-solid coupling, with numerical simulation of engineering examlpe of the slope. The corresponding characteristics of the numerical simulation damage and the examlpe are exactly the same, which prove that the numerical simulation is feasible, and what’s more, with numerical simulations, effects of kinds of factors on slope stability subjected to rainfall are analyzed with its scope and depth of damage and infiltration depth of rainfall, from which it can be concluded that the intensity of rainfall and duration and long-term strength have more effects on slope stability subjected to rainfall.

Based on the previous study and comparative analysis of two current calculating models, a new calculating model of prestressed double-row piles is presented, considering the double-row piles and soil between piles as dimensional equivalent truss and pile end as elastic restraint and meanwhile adopting the method of exerting vertical prestress on back-row pile to balance pile-side soil pressure and improve the mechanical performance of front-row and back-row piles. The calculating models of dimensional equivalent truss and the method of exerting vertical prestress on back-row pile are essentially verified by comparative analysis of three calculating models and FEM programme. Combining with engineering example, the key factors influencing prestressed double-row piles are analyzed. Both the calculating analysis and the engineering application show that a satisfactory result can be obtained with spatial equivalent truss and the method of exerting vertical prestress on back-row pile.

Based on a model of coupling thermo-hydro-mechanical dynamic response for a saturated poroelastic medium presented by the authors, the dynamic response of a spherical hollow chamber when subjected to a time dependent thermal/mechanical shock on the inner surface is investigated. By using Laplace transform method, the governing equation is decoupled; and the integral solutions of temperature, displacement, pore pressure and stress are derived. The numerical results are obtained by using the inverse Laplace transform method; and the results are used to analyze the influences of the coupling parameters of thermo-hydro-mechanical dynamic response. At last, the solutions are compared with those of the thermoelastic medium; and the validity of the results of the thermo-hydro-mechanical dynamic response with a spherical hollow chamber in the saturated poroelastic medium is ascertained.

By analyzing the dynamic course of the surface subsidence due to underground mining, the conclusion has been drawn that the w-t curve of the ground subsidence appears S-shaped. The ground subsidence is increasing from 0 to the maximum and then decreasing to 0 in the subsidence process. So the time function which can describe the subsidence course of the ground must fit not only the w-t curve but also the v-t curve and the a-t curve. Time functions which are usually used to fit the w-t curve of the foundation or roadbed settlement now such as the exponential time function, the hyperbolic time function, the Gompertz time function, the logistic time function and the Weibull time function. Studying the w-t curve, v-t curve and a-t curve of these time functions finds that only the Weibull time function is feasible for describing the dynamic course of the ground subsidence due to underground mining. Two examples using the Weibull time function to fit the observation data of the dynamic course of two coal mine’s ground surface subsidence verify the test.

Many tunnels need cross the bottom of the existing pipelines during metro station excavation. Surface settlement and ground loss can be found during tunnel excavation; and the deformation of underground pipeline is brought consequently. In general, the key measure to pipeline recovering is grouting, which means grouting in subjacent bed to raising the pipeline. Based on the project of raising an existing pipeline by grouting during the construction of Huangzhuang station of Beijing metro, 3-D finite difference method is used to study the feature of pipeline deformation caused by tunnel excavation. In numerical simulation, expanding pressure is applied to the grouting elements to simulate the heaving effect of the pipeline; strain-softening model is suitable for simulating elastoplastic behavior of soil, and embodying the interaction between grouting and soil. The conclusions of numerical analysis agree well with the in-site measured data, which can contribute to the construction and design of raising pipeline by fracture grouting in tunneling.

The problems, such as pavement cracking, differential settlement between bridge and roadbed, are the most important matters that engineers must be up against. The simulation of soft ground settlement is one of the difficulties. This coupled simulation of seepage and consolidation mainly uses the improved Cambridge model, depends on the software FLAC3D which is a finite difference software. As an example, the test sections’ data of an expressway in the Pearl River Delta is used for simulating soft ground settlement, the accuracy of this modeling can be validated by contrasting between the results and actual monitoring data. The result shows that the simulating numerical values and the measured data has good match, whether for the surface settlement or for the stratified settlement, it means that the simulating model can be used to reflect the soft ground settlement.

A new displacement time series predicting model was proposed by combining the support vector machines and Markov Chain, named as support vector machines-Markov chain (SVM-MC) model. Through studying the measured displacements, SVM optimized by particle swarm was used to dynamically forecast the trend of macro development. Markov chain was applied to compute state transition probability matrix. By classifying system state and calculating absolute error and relative error between measured values and SVM fitting values, the predicting results are improved. The model was used to predict displacement time series of a high slope of a permanent shiplock. The engineering case studies indicate that the model is scientific and reliable; and there is engineering practical value for displacement time series predicting.

Based on the analysis of discontinuity and anisotropy of columnar joints, a 3D numerical simulation is carried out for an arch dam and its foundation. Considering the initial ground stress of river valley and anisotropic mechanical property of rock mass, the computation results with isotropic and anisotropic models are compared and analyzed. The result shows that the characteristics of columnar joints have obvious influence on the stress and displacement of engineering rock mass. The influence of columnar joints on dam or abutment stability is very important; and a successful application is provided for the analysis of anisotropic property of rock mass in this dam area.

It is common that the foundations have under soft layer in engineering; however their failure mechanism depends on assumed condition and experience to a large extent. The paper carries out strain controlling numerical experiment for a foundation model with under soft layer based on limit analysis and fast Lagrangian numerical simulation method; the simulation result shows obvious size effect. Simulation also gets the different ultimate bearing capacities, stress-strain curves, progressive failure pattern, and the under soft layer settlements corresponding to different loading sizes. The safety factors respectively acquired by load increasing method and strength reduction method based on above numerical model are also compared, they have the same changing trend according to the loading size changing; but the value of former is smaller.

The method of combining the theory of finite element calculation of parameters in model of rockfill dam coarse grain material with the immune genetic algorithm (IGA) is confirmed; and a relevant software is developed. Using the large scale loading test data of Gongboxia dam, constitutive model parameters of rockfill are gained. It is concluded that because the mica schist is mixed with feeble weathered granite, the grain is broken up severely; the back-analysis parameters of explosion rockfill(3BⅠ)are lower than the results of laboratory triaxial test, and the Duncan E-B parameters obtained by back-analysis of her sandy gravel (3BⅡ)are higher than the triaxial test results of laboratory triaxial test which can not reflect the mechanical behaviors of the dam material objectively; the research should be strengthened in 300 m high rockfill dam construction. The fitting modes of the space displacement field of prototype observation are also explored and it turns out that the results of IGA analysis considering only vertical deformation meet the need of dam’s technical accuracy.

There are some thorny problems such as uncertainty and instability solution produced by initial parameters when hierarchical optimization is applied to the viscoelastic cavern displacement in parameter inversion. A simple search method is used in the hierarchical optimization. The hierarchical pattern search is provided to solve these problems. A new method has some computing strategies based on least-square method, which can avoid iterative non-convergence when initial parameters are not optimally selected. Numerical results show that the hierarchical pattern search is nearly independent of the original value; and the method has high accuracy and validity for the viscoelastic cavern displacements of parameter inversion.

A 3-D model for numerical calculation of landslide is proposed; and a high-precision eight-node hexahedron element is used to build the finite element grid of slip layer. The slip layer material is simulated by an ideal elastoplastic model based on the Mohr-Coulomb criterion. Three-dimensional stress state and slide direction of the slip layer zone are obtained by numerical computation. So based on the analysis of the three-dimensional stress state of the slip layer zone, a point safety factor as the ratio of the shear strength of the slip zone to the shear stress parallel to the gliding direction is defined; and the safety factor of the landslide as the weighted average value of the zone point safety factor with its zone is defined. The sliding mechanism is studied through zone point safety factor; and landslide stability can be evaluated through the safety factor. The case studies show that the calculated results are consistent with the actual cases.

The software ANSYS is one of the most powerful nonlinear finite element analysis programs in the world. It includes different kinds of material models. However, the ANSYS currently lacks modified Cambridge constitutive model which has been widely used to simulate the stress-strain behavior of soil in geotechnical engineering. The secondary development tools UPFs and data interface have been used to add the modified Cambridge model to standard ANSYS procedure. The key technology of secondary development is the compilation of subroutine UMAT. F. The subroutine must in accord with the constitutive equation of the modified Cambridge model and the rule of finite element computation. Its variable names and input-output formats must be consistent with standard ANSYS procedure. A numerical example is given; and the result verifies that the secondary development of the modified Cambridge model is valid. The method mentioned can be extended to add other material constitutive models to standard ANSYS procedure.

When bilaminated rock mass is numerical analyzed by conventional finite element method ,that the shortcomings produced is not only the huge modeling workload and maneuverability become more inefficient with layer numbers increasing; but also the method can’t reflect the bending deformation of the layered material. The Cosserat medium expanded model is a equivalent methods aiming at the complex rock mass. The basic principle of the Cosserat continuum theory and its expanded constitutive model are introduced firstly; and the Mohr-Coulomb plastic yield criterion of the new model is given. Then the FEM program is written by using Matlab system; and it is applied to the underground caverns. The results of comparison between Cosserat model and conventional continuum model are presented; and it is shown that the program based on Matlab and Cosserat model is effective, applicable and superior.

Temperature in tunnel and temperature of surrounding rock which distribute in distinct regions and mountains are always different, and even have great differences sometimes. Accordingly, although under the same pouring materials and operating conditions, the temperature and the thermal stress of the lining concrete which will affect the occurrence and control of the temperature cracks to a great extent are also different. Taking Xiluodu free-flow tunnel as a research object, a 3-D finite element method is applied to simulate the construction process under conditions of different air temperatures in tunnel and temperature of surrounding rock. Through comparing the maximum temperature, maximum temperature difference between inner and surface, minimum temperature, maximum tensile stress in early period and winter, the effects of the change of temperature in tunnel and surrounding rock on the temperature and thermal stress of the lining concrete as well as occurrence, development and control of the temperature cracks are analyzed. The results show that both the temperature in tunnel and the temperature of surrounding rock have significant influences on the temperature field and stress field of the lining concrete. The lower the air temperature in tunnel is, the easier the early cracks will occur in winter; and it is necessary to prevent both early cracks in summer and winter cracks. The tensile stress of the lining concrete increases obviously when the temperature of the surrounding rock is low, however, the effect on the stress of the surface and inner is small; so the temperature of the surrounding rock has little effect on the temperature cracks. The research results provide valuable references for the design and construction of tunnel engineering.

By using ANSYS/LS-DYNA, 3D nonlinear dynamic finite element software, an elasticity calculation model is established to analyze the distribution and transmission of stress under explosive charge in multi hole and the same delay time; the stress distribution nephogram and stress-time curves of some typical elements of the mode in different times are obtained. The transmission of stress waves and the formation of blasting crater are shown. The factors influenced the formation of blasting crater are discussed. The research results of numerical simulation have been proved by field productive application.

A kind of image capture and displacement measurement system in centrifuge modeling is developed based on the idea of store forward. The system consists of five subsystems: image capturing subsystem, data storing subsystem, communication subsystem, analysis and processing subsystem, and supporting subsystem. This system can capture high quality images during the centrifuge model test. It can obtain the displacement field at any spot at an arbitrary time of the soil. It has the advantages of high automation, high precision, less preliminary preparation and noninterference to the soil. Using this system, the centrifugal modeling tests are used to conduct the failure process of a cohesive soil slope. The results show that the failure process can be divided into three phases; the strain localizations occur at the top and toe of the slope due to loading application.

Application of unsaturated soil mechanics to practice requires measurement of soil suction, but suction measurement can be expensive, difficult, and often impractical to obtain with the normal used methods. A model for predicting the matric suction of unsaturated soils from soil electrical resistivity measurement is proposed. Based on the laboratory test results, the corresponding electrical resistivity parameters of , and A are calculated; where , and A are average formation factor, average shape factor and anisotropy index respectively. The variation of these three electrical resistivity parameters and matric suction with volume water content are studied, respectively. The parabola relationship between the comprehensive structural parameter and matric suction is identified. A parabola equation of and matric suction is proposed. Prediction of matric suction from electrical resistivity measurement allows for a simple, inexpensive and practical description of the behavior of unsaturated soil.