Large deformation may occur in the post initial liquefied sand undergone the dynamic loading. The definitions of shear strain rate and apparent viscosity in fluid mechanics are introduced to analyze the dynamic hollow torsional tests of post initial liquefied sand. There are two states in the post liquefied sand: zero effective stress state and non-zero effective stress state. The conclusions show that the sand characterized by shear-thinning non-Newtonian fluid in zero effective stress state which is similar to the static torsional tests. The loading cycle number does not have influence on the shape of flow curves under shear–thinning state except for the amplitude of shear strain rate, which increases with the increase of cycle number. Under non–zero effective stress state, the apparent viscosity increases with the increase of strain and the decrease of pore pressure. The apparent viscosity, which obtained from all tests, has a unitary formulation with the pore pressure ratio.

To evaluate the influence factors of cumulative plastic strain of saturated soft clay, the cyclic triaxial tests with stress-controlled are conducted to investigate the behaviors of soft clay subjected to cyclic loading. The research results include four aspects. Firstly, there are three types of cumulative plastic strain of saturated soft clay under cyclic loading, such as stable type, destructive type and critical type. Cumulative plastic strain of saturated soft clay increases with repeated load when dynamic stress is less than the critical dynamic stress. But the increasing rate slows down until it trends to a stable value. On the contrary, the strain increases quickly with repeated load until clay is destructive. Secondly, a new mathematical function, containing three parameters, is suggested to fit the curve of cumulative plastic strain of saturated soft clay versus repeated load under cyclic loading. The influence laws between parameters and dynamic stress are analyzed. Thirdly, based on the influence laws, a method for confirming the dynamic stress without static deviator stress is put forward. Finally, an empirical equation for cumulative plastic strain which derived from the mathematical function, containing dynamic stress, confining pressure, static deviator stress and repeated load is synthesized.

trength reduction method and gravity increase method are introduced into the discrete element method for experimental study of slope safety factor. The research of slope stability is carried on by using particle flow code (PFC) software and adopting strength reduction and gravity increase methods, and the result is close to the calculation results of finite element method and slice method. The method opens a new way for calculating slope stability. If using PFC to solve the slope safety factor, slice method is not needed, namely it does not need to make an assumption of the inter-slice force. And at the same time, it does not need to assume the position and the shape of the sliding surface, because the particles adjust their positions according to their received contact forces; and finally, the shear failure of the slope occurs on the weakest surface of shear strength. Different viewpoints are put forward about inequality proportion reduction of strength reduction method, which provide new speculations for future research.

How to determine the mechanical behavior of the elastoplastic deformation and stress redistribution in rock mass without supporting reaction after tunnel excavation is the important research problem all the time. The insufficiency and defect existed in the solution of Kastner equation are as follows: (1) there are drawbacks in the mechanical treatment of supporting reaction, which has no practical meaning; (2) in the solution of plastic zone stresses, it takes no advantage of the plastic constitutive relation given by perfect elastoplastic materials; (3) in the solution of plastic zone stresses, the influence of axial stress along tunnel is not taken into account. The perfect elastoplastic solution based on the incremental constitutive relation of plastic mechanics, namely Levy-Mises relationship and D-P yield criterion, is addressed. The present solution is studied with calculation results by Kastner equation and numerical computation. It has more theoretical meaning and practical value, for the present solution, it is able to account for three problems neglected in the solution of Kastner equation.

Based on non-full horizontal-vertical (H-V) reinforced clay, a series of consolidated undrained triaxial tests are carried out to investigate the strength and deformation properties of clay reinforced with H-V inclusions, in which the galvanized iron sheet and plexiglass are used as reinforcing materials. The behaviour of clay reinforced with different vertical reinforcements is studied in terms of stress-strain relationship, strength property and failure mode. The influences of vertical reinforcement, confining pressure and reinforcing materials on the strength of reinforced clay are discussed. The results show that the peak deviator stress and shear strength increase greatly for clay reinforced H-V reinforcing elements as compared to unreinforced clay and clay reinforced with conventional horizontal inclusions.

Saturated seepage flow plays an important role to cause instability of soil-rock mass. The destruction forces, the passive “buoyant force” and the active “seepage force” induced by seepage are described. The mutual converted relation between seepage forces and boundary water pressures as well as their correct application to piping and landslide problems is discussed in detail. Using seepage force instead of boundary forces in landslide computation is recommended for its simplicity and accuracy. Misunderstanding about seepage force used in computation and design code is pointed out.

In-situ pull-out model test and numerical analysis FLAC3D are integrated to study the mechanical behaviors of tunnel anchorage. The in-situ model test of west anchorage of Baling River Bridge is introduced in detail. According to the model test, it is found that the displacement of cross-section shows saddle-shaped, and trapezium-shaped along the axes. The rate of residual displacement appears V-shaped. The monitoring displacement of large scale model is bigger than that of the small one. From the numerical analysis, it is found that the stress distribution shows subsection character, and the stress distributes unsymmetrically along anchorage. And plug-shaped tensile-shear complex failure caused by anchorage in surrounding rock may be a failure mode. The rock mass in damage zones and prominent deformation zones should be paid more attention to during design and construction.

It is nonnegligible that the Rayleigh wave (R-wave) appearing and transmitting in soil subjected to impact loading (dynamic consolidation in engineering, DC for short). The research on mechanism and effect of R-wave on foundation is made in DC, where the transmitting characteristics，the influenced depth, the laws of deformation and volume variations of R-wave are discussed by means of the vibration characteristics of soil. It turns out that R-wave in DC is effective for the foundation; it is able to influence the depth about one wavelength, and can compact the soil under the hammer. On the other hand, it has some negative effects on the surface of foundation beside the tamping pit. The solving method of dispersion curve of R-wave in the layered foundation and the method of estimating the influenced depth of DC scientifically can be obtained. But Menard’s conventional formula can’t make a precise calculation of the depth. The practical examples are provided to verify the conclusion that DC can benefit more than destructive effect from R-wave.

Based on the uneven consolidated condition, the lime-treated expansive soil is studied, the influences of different consolidation ratios and deviator stresses are considered. Through dynamic triaxial test, dynamic characteristics of 3 % lime-treated expansive soil under 6 selected consolidation ratios are studied; the impacts of various consolidation ratios and deviator stresses on it are concluded. In the range of analyzed consolidation ratio, the dynamic modulus of lime-treated soil increases markedly as long as consolidation ratio and deviator stress increase. The damping ratio is influenced by consolidation ratio as well; but the impact on damping ratio is less than that on dynamic modulus.

By using a conventional consolidation apparatus, seepage characteristics of ultrafine granular soil affected by ion concentration of pore solution are performed, and consolidation characteristics of four sets of bentonite samples of pore solutions with different contents of NaCl are tested under the same test condition. Consolidation curves and relevant consolidation coefficients are obtained; and seepage coefficients are obtained based on consolidation coefficients. The comparative analyses of hydraulic conductivity of samples of each group show that ion concentration is an important factor that influences on seepage. The hydraulic conductivity of soil increases as ion concentration increases. It is concluded that the change of the thickness of diffuse double layer on granular clay surface with ion concentration may be a key factor influencing on ion effects of granular soil seepage. The test results have contribution to understanding the origins of the ion effects on soil seepage, and are of guiding significance for improvement and perfection on existing seepage and consolidation theories of soil.

Creep tests under four-step loading to predict long term creep behavior of composite geomembrane are examined. Based on theoretical analysis, a creep model for composite geomembrane is established, which shows the relationship between creep behavior of composite geomembrane and loading. The creep strain increases with the increase of loading. Under long term tensile dead load, the composite geomembrane presents strong lateral contraction property, and the necking magnitude is proportional to the load. When the material strength remains around 70 % under ultimate load less than 60 %; the material can be seen reliable, it has no influence on structural reliability.

Using micrographic visual tracing and digital information real-time processing techniques combined with digital image identification method, the piping process is traced and recorded. The complicated variations of hydraulic and geometric features are disclosed mesomechanically. The dynamic changes of pressure, hydraulic gradient, particles displacement field and porosity etc. are obtained; and the influence of pressure rate on piping, the moving characteristics of particles, the distribution of particle losses and the penetration of leakage passage are analyzed. The results indicate that water soil interaction exists during the whole process of piping.

In the realm of rock project, the fatigue failure characteristics of rock under cyclic load and long-term stability of rock mass are closely related. At present, researches for fatigue damage of concrete are more than that for rock, in view of this situation, using damage mechanics method, the fatigue damage variable expression based on accumulated plastic strain is analyzed; according to the theoretical shortcoming of the used damage variable expression based on accumulated plastic strain, a new rock damage variable expression method is established. At the same time, in order to study the deterioration process of rock mechanical performance under fatigue load, the damage development and deformation law of rock under fatigue load are analyzed according to continuum damage mechanics; and a low cycle fatigue damage evolution equation is deduced and established considering hardening characteristics of rock; the evolution equation reflects fatigue damage evolution rule of rock well after experimental confirmation, and it can be used for finite element analysis of rock under fatigue load.

The technological and uplift tests of underreamed anchors are carried out based on the development of mechanical underreamed devices of anchorage. The results show that the mechanical underreamed device has good adaptability for geology conditions; the bearing capacity of underreamed anchor increases by 20 %-30 % on an average than that of the normal anchor, and the maximum bearing capacity increases by 66 %; the phenomena of axial strain steep dropping for underreamed anchor show the end-bearing effect of underreamed anchors obviously.

The experimental tests of Fujian standard sand with relative density of 30 % are performed by using soil static and dynamic universal triaxial and torsional shear apparatus. A series of stress-controlled drained monotonic shear tests are conducted under complex stress conditions with constant mean principal stress. The coefficient of intermediate principal stress and orientation of principal stress are varied so that their coupled influences on shear behaviors of saturated sand are explored. Based on the comparative experimental results, under the same initial condition, coefficient of intermediate principal stress influences the stress-strain relationship of saturated sand, but does not make obvious effect on volumetric strain features. It is shown that the drained shear behaviors of sand are not dependant on consolidation stress ratio and considerably depend on coefficient of intermediate principal stress as well as orientation of principal stress. Furthermore, both coefficients of intermediate principal stress and orientation of principal stress affect friction angles at phase-transformation state(PTS) and at peak state. Finally, introducing a factor for weighing the influence of orientation of principal stress, and combining with the test results, an expression for strength indices taking coupled effect of coefficient of intermediate principal stress and orientation of principal stress into account is obtained by using generalized twinshear stress criterion.

Without considering continuity and nonlinearity of subgrade is the limitation of Winkler model; and it is modified by Lifking model. However, the effect of foundation shape on coefficient of subgrade reaction considered by Lifking model is excessive. Asymmetry of coefficient of subgrade reaction along long and short sides of rectangular foundation is also caused. Nonlinear generalized Winkler model is presented to overcome the disadvantage of Lifking model, and to redefine the characteristic function of Winkler model. Nonlinear generalized Winkler model not only considers the effect of foundation shape and size on rigidity of subgrade reaction but also simulates several typical forms of subgrade reaction distributions. The nonlinear generalized Winkler model simulates the practical p-s curve by piecewise linear approximation. The nonlinearity of subgrade is also considered. The example results show that nonlinear generalized Winkler model is rational and available.

Traditional cylindrical cavity expansion theory is based on the isotropic initial stress supposition. However, the cylindrical cavity is usually expanded in case of horizontal initial stress unequal to vertical initial stress, such as the horizontal directional drilling in tunnel engineering. A new elastoplastic cylindrical cavity expansion solution is introduced, in which the anisotropic initial stress is explicitly considered. Case study results indicate that the cylindrical cavity expansion with anisotropic initial stress yields a larger plastic zone than that with isotropic initial stress when the rest geometrical and geomaterial parameters are the same. The results also demonstrate that the cylindrical cavity expansion with anisotropic initial stress results in a smaller ultimate expansive pressure than that with isotropic initial stress.

Rock is a complex heterogeneous geological material with three-phase law in fatigue damage evolution. This law can be described well by inverted S-shaped nonlinear fatigue cumulative model. The parameters of this model under different stress levels must be determined before using it to calculate damage or analyze fatigue life. However, the calculating result indicates that the probability is very low for Levenberg-Marquardt method converging to optimal solution with arbitrary initial parameters. Therefore, a finite combination method is proposed to estimate initial parameters for Levenberg-Marquardt calculation. Initial points uniformly distributed in the feasible region of parameters are inputted for Levenberg-Marquardt calculation; and the set of parameters with minimum residual sum of squares is taken as final initial parameters. The results show that the set of initial parameters estimated by finite combination method is always effective for Levenberg-Marquardt method converging to optimal solution.

The stability of jointed rock slope is controlled by shear strength of joints and rock simultaneously. Based on the instability failure mechanism of jointed rock slope with two sets of parallel joints, a new limit equilibrium method is studied; and the corresponding formulae for stability analysis are deduced. A program is developed for the validation of this method. Through the comparison between the results obtained from the new method and those from reference [4], it is shown that the new method for stability analysis of jointed rock slope is correct; and it is also an effective approach for the stability analysis for jointed rock slope with two sets of parallel joints.

Combining with soft foundation treatment project with dynamic drainage consolidation method(DDCM) in Guangzhou International Convention and Exhibition Center, an indoor model test is designed according to in-situ construction process. Pore water pressure in saturated soft clay is measured when inserting plastic drainage boards during dynamic compaction and after compaction. The results show that the pore pressure at each location reaches its peak at different times after inserting plastic drainage boards completely. During impact process, the nearer a point is to the impact point, the faster and the greater the pressure increases; under a certain impact number, pore pressure at shallow location tends to increase very slowly; but pore pressure at deep location continues to increase after impacting completely, pore pressure at every location dissipates basically consistent.

The origin and the potential influence of two forms of consolidation coefficients in classic consolidation theory are discussed. Various computational methods for change rate of volume element are a major reason for resulting in two kinds of consolidation coefficients. According to finite-strain theory, the small-strain consolidation coefficients proposed by Terzaghi (1943) and Terzaghi & Fröhlich (1936) which differ from that obtained earlier by Terzaghi (1923), have Lagrangian coordinate and Eulerian coordinate backgrounds respectively. The small-strain consolidation coefficient in Gibson’s large-strain consolidation theory generally uses the definition proposed by Terzaghi & Fröhlich (1936), leading to a considerable controversy on quantitative results obtained previously with respect to the differences between Gibson’s theory and classic consolidation theory. From the application point, the differences between two kinds of consolidation coefficients in classic theory depend on stress level, structure characteristics of soils and so on.

Besides through the defect of geomembrane, the transfer of organic contaminant through intact composite liner is an important way. A one-dimensional model for analyzing organic contaminant transfer through intact composite liner is established, and then an analytical solution of organic contaminant transfer through intact composite liner is obtained. The comparison between analytical and numerical solutions shows that the analytical solution is reasonable. The effects of GCL and CCL composite liners preventing leakage on organic contaminant are analyzed. CCL composite liner is more effective, and the effectiveness can be improved through modifying soil and its thickness. The choice of organic contaminant influences the result of GCL composite liner greatly, and the change of retard coefficient can be ignored.

In order to control the influence of pouring concrete of bridge piles on the ground temperature in permaforst regions and guide the subsequent engineering construction, it is necessary to analyze and study the temperature distribution along piles. Considering the characteristics of piles in permafrost regions and the basic rule of heat transfer in soil during freeze-thaw cycling, the control equations of temperature field in permafrost regions are established based on the theories of porous media and thermodynamics. The effects of heat conduction and latent heat on the temperature distribution are considered, and the release rule of concrete hydration heat is studied by control equations. The research results are compared with the in-situ monitored temperature field of a bored pile with large diameter in Tibet. It is concluded that the calculated results are in good agreement with the in-situ monitoring data. Based on this, emphasis is laid on analyzing the changes of soil temperature around the pile in different depths with time and temperature distribution in the radial direction of pile diameter in different phases. It is of great theoretical and practical significance to the foundation stability of bridge and culvert as well as the traffic operation safety of highways and railways in permafrost regions

Based on the theory of image method, the formulas of superimposed stress induced by ground loss are obtained. Combining the formulas of superimposed stress induced both by bulkhead additive thrust and frictional force between shield and soil, which are based on the Mindlin solution, the formulas of total soil stress are obtained. The distributions of superimposed load on parallel tunnel, which are caused by all of the factors, are analyzed by using an analytical calculation case. In the analytical process, the distribution of superimposed load caused by ground loss is discussed emphatically. The result obtained will have some referential value in parallel tunnelling.

Both the driving response and the bearing capacity of open-ended piles are affected by the soil plug that forms inside the pile driving. Field tests are conducted to investigate the plugging behavior of long PHC pile during driving into soft clay. Based on the field tests of long PHC pile in Shanghai soft foundation, soil plug data of 44 piles in three different fields are analyzed. For the PHC piles, the soil plug length is continuously measured during pile driving, allowing calculation of the incremental filling ratio (IFR) and the plug length ratio (PLR) for the pile. The test results show that normalized plug length (the ratio of plug length to pile inner diameter) and IFR vary with normalized pile length (the ratio of pile penetration depth to pile inner diameter) for different types of piles. It is shown that the value of IFR decreases for long PHC pile driving through shallow soil layer into deep soft soil, and the value of IFR increases for long PHC pile driving through deep soft soil into bearing stratum (fine sand). A relationship between IFR and PLR is proposed. The relationship between IFR and PLR allows the quick estimation of IFR based on the measuring data of PLR.

Rotated branches pile is a new developed pile based on DX pile and squeezed branch pile. They have similar figures and bearing mechanisms to a certain extent. The former is rotated and the latter is squeezed in pile molding, so the bearing behaviors are different. There are problems in calculating bearing capacity of former pile by using the formula of latter pile for a project in Luoyang, a formula of bearing capacity of rotated branches pile is proposed.

54 samples, which are divided into 9 groups, are carried out in the lab to study the relationship among compression index of solid wastes, moisture content, organic content and void ratio. There are two groups of samples with different dimensions used to contrast the influences on dimensions. The influences of initial water content (w), initial void ratio (e0) and the content of easily degradable organic (B0) on compressibility of solid waste are analyzed emphatically. e0 changes from 2.5 to 4.6; w changes from 50 % to 100 %; B0 changes from 10.1 % to 45.1 %. The results show that compression indexes are from 0.824 2 to 1.234 6; modified indexes are from 0.165 9 to 0.243 6; they are basically consistent with similar foreign research results. The suggested value taking method of compression parameters considering initial physical parameters of municipal solid waste is proposed. It provides references for engineering practice.

Classical sanitary landfills release large amounts of hazardous and deleterious chemicals to nearby groundwater and air via landfill leachate and landfill gas (LFG). LFG which generated by municipal solid waste (MSW) in landfills brings much trouble to environmental pollution problem. LFG contains important greenhouse gases, such as methane (CH4), carbon dioxide (CO2); and LFG is a main environmental pollutant; landfill gas is also a clean renewable resource and energy; recovering and utilizing LFG can bring economics, environment safety, energy, and resources benefits. The utilization of LFG is concerned on the utilization of methane in LFG; then the calculation method of methane emission from landfills is introduced and interpreted briefly. The methane emission of China from landfills is calculated by first order decay method; the range of methane resources quantity in landfill gas is obtained. Based on clean development mechanism and the actual LFG utilization situation in China, utilization methods to address the emission of landfill gas are analyzed; the situation and the problem faced by LFG utilization in China are analyzed; and the advices and results are given. Those results and advices may be helpful to the recovery and utilization of landfill gas.

The support for deep soft rock and dynamic pressurized roadway is a major technical challenge. The -620 soft rock roadway in Kongzhuang Mine which is located in the high stress areas is a typical example, and it is affected by No. 7335 hydraulic mining face above, No. 8331 mining face, and the fault as well; the damaged condition and the factors that cause the damage are analyzed. The main roadway deformation rules affected by mining are simulated, the change and the influence area of stress state of main roadway are obtained. The thought of reinforcing main roadway is proposed; the reinforcement is optimized; and the reasonable parameters of reinforcement are determined. The research results indicate that the main roadway deformation can be effectively controlled by adopting the bolt-mesh-anchor-concrete and bolt-grouting combined support technology, which grouts main roadway within a radius of 2 m with a new patent grouting anchor. Through the comparison of the mechanical properties of surrounding rock before and after grouting, live shooting and strata control observation, the underground industrial test shows that the -620 main roadway has been effectively controlled.

There are a few researches on predicting subsurface ground movements induced by shield tunneling via brief estimating method till now. Based on the method used to calculate ground elastic displacement around deep tunnel and some researches on gap parameter of shield tunnel, a brief method for estimating subsurface ground horizontal movement induced by shield tunneling is presented. And a new method is presented to describe the profile of ground settlement around a shield tunnel. And then it is used to estimate subsurface ground settlement with the equation presented by Mair. And the feasibilities of these proposed methods for estimating subsurface ground movements induced by shield tunneling are verified via contrasting their analysis results with finite element analysis results and measured data of some typical project cases.

Baziling forked tunnel along Shanghai-Chengdu Expressway in construction is an unsymmetrically loaded tunnel. Construction process of forked tunnel is very complex because the forked tunnel includes twin-bore section and small clear spacing section. So, it’s important for forked tunnel to adopt appropriate construction process. In order to simulate rock mass properties veritably and analyze damage failure of rock in construction, the coupling model of elastoplastic damage is presented based on irreversible thermodynamics theory. 3D elastoplastic damage finite element code D-FEM is programmed by FORTRAN language. A large 3D numerical model of forked tunnel is set up and different construction processes are simulated by D-FEM. Through analyzing displacement, stress and damage yield zone of tunnel surrounding, the optimum construction process that left tunnel excavates ahead of right tunnel 32 m is determined, left tunnel and right tunnel excavate synchronously is proposed.

The commonly used method to control and stabilize expansive soils is to add stabilizing agents, such as lime, fly ash or cement. Electrical resistivity of soil can be considered as a proxy for the spatial and temporal variability of many other soil physical properties. Because the method is non-destructive and very sensitive, it offers a very attractive tool for describing soil physical properties. The electrical resistivity of lime or fly ash treated expansive soils changes with the development of physicochemical process in the stabilized soils. The purpose of this work is to evaluate the potential application of electrical resistivity measurements for detecting the physicochemical process in lime or fly ash treated expansive soils. A series of experimental programs are performed to study the relationships among electrical resistivity, swell potential, swelling pressure, unconfined compressive strength during curing time. Four different zones named instantaneous reaction, principal reaction, residual reaction and steady phases are divided. A new, simple electrical resistivity method is put forward to evaluate the swell potential and shear strength of stabilizer-treated expansive soils. Its practical implication is validated by experiment results.

In order to evaluate each main factor influencing the seepage control of underwater tunnel fissured surrounding rock exactly, analytic hierarchy process is adopted, main factors influencing the seepage control of underwater-tunnel fissured surrounding rock are analyzed, and each weight is determined based on analyzing hydraulic characteristics of fissured medium combined with engineering experience. The results show that the mean width of fault fractured zones of surrounding rock and other ones per meter length of tunnel has the maximum weight, it is the uppermost ingredient influencing the seepage control of underwater tunnel fissured surrounding rock; it’s also influenced by water yield property of overlaying aquifer and the average number of surrounding rock gapping fissures per meter length of tunnel. In addition, after setting cavern location and its dimension and other parameters, the mean width of surrounding rock fault fractured zones and other ones per meter length of tunnel, the water yield property of overlaying aquifer and the average number of surrounding rock gapping fissures per meter length of tunnel are the main factors influencing the seepage control of underwater tunnel fissured surrounding rock. Furthermore, the research results may afford the scientific bases for the seepage control and disaster prevention of subsea tunnels, underground hydraulic seal oil storage rock caverns and other underwater tunnels.

Based on Biot′s consolidation theory under plane strain, the effect of disposing soft soil foundation using geotextile and plastic drainage plate is studied with nonlinear finite element method. It is shown that the vertical settlement of foundation with drainage plate is larger than that without drainage plate; the lateral displacement decreases and the uplift at the toe of embankment decreases at the same consolidation time. In general, the dissipation time of excess pore pressure is shortened greatly by using plastic drainage plate; the stability of embankment is improved for accelerating the consolidation so as to enhance the bearing capacity of soil. Meanwhile, the shared tensile force of geotextile becomes lower when plastic drainage plate is used. In order to reinforce the embankment effectively, it is advised that geotextile should be set on high-stress zone. Furthermore, the design can be optimized by shortening the standing time of consolidation when plastic drainage plate is used.

Based on Biot′s consolidation theory under plane strain, the effect of disposing soft soil foundation using geotextile and plastic drainage plate is studied with nonlinear finite element method. It is shown that the vertical settlement of foundation with drainage plate is larger than that without drainage plate; the lateral displacement decreases and the uplift at the toe of embankment decreases at the same consolidation time. In general, the dissipation time of excess pore pressure is shortened greatly by using plastic drainage plate; the stability of embankment is improved for accelerating the consolidation so as to enhance the bearing capacity of soil. Meanwhile, the shared tensile force of geotextile becomes lower when plastic drainage plate is used. In order to reinforce the embankment effectively, it is advised that geotextile should be set on high-stress zone. Furthermore, the design can be optimized by shortening the standing time of consolidation when plastic drainage plate is used.

Taking the numerical analysis software（ADINA）for large-scale geotechnical engineering as research method, based on unloading rock mass mechanical theory and method, excavation unloading of high slope of a highway is analyzed. The primary condition, excavation condition, unloading condition, reinforcement condition are considered and compared with monitoring data. The strong unloading region next to excavation face and the deterioration of rock mass parameters of the region are considered in unloading rock mass mechanics, the calculating results agree well with the monitoring data. The result verifies the rationality of the method of unloading rock mass mechanics in calculating slope excavation and provides guidance for post-stage operation of slope; and it also can be meaningful and helpful to other projects.

An engineering example that a deep foundation pit is in dangerous status caused by over excavation in soft clay is described. The soil layers mainly including mucky silty clay is typical and representative floodplain of the Yangtze River. During pit excavation, the depth of foundation pit increases because the basement project is adjusted, meanwhile the retaining structure is not reinforced in advance, which does not satisfy the design requirements, so as to lead to dangerous status of the pit. Through comparing the internal force and the displacement of retaining structures at different excavation depth conditions, the reasons why the dangerous situation occurs are analyzed. Based on the deformations of retaining structures and surroundings, the effective treatments according to the foundation pit problems are proposed to ensure the foundation pit safety.

State vector is a method for describing coarse graining of continuous field in statistical physics. Introducing it into landslide forecasting, by dividing landslide hazard into n subregions, the state vector analysis is done to a series of monitoring data of subregion in every time window; through stacking modules of rainfall and monitoring data state vector after normalization, development and variations of state vectors of landslide displacements in a period are studied; and a new method is proposed to forecast landslide by using state vector. Taking Xintan Landslide for example, accumulative horizontal displacement is analyzed by state vector; it is found that the modulus and the incremental modulus of sate vector both make mutation before the landslide obviously, according to the variation of state-vector curves, based on the grading method of landslide early warning, three-grade landslide early warning is put forward; the highest warning level forecasts the landslide time is two days earlier than that of actual landslide. The result shows that the mutation of state vector is the precursory of landslide, which can be used to predict the landslide in short time and imminent sliding.

Based on the measured data of soil nailing wall, the ratio of lateral displacement to vertical displacement is discussed. The correlation between lateral and vertical displacements is developed by using statistical method. Some key factors about deformation of soil nailing wall and the effective way to control the deformation of soil nailing wall strictly are pointed out. The analysis shows that space effect on deformation of soil nailing wall is obvious; excavating slope and slope top unloading can control the deformation of soil nailing wall effectively; prestressed anchor on the upper of foundation pit can largely restrain the foundation pit deformation; the increment of vertical displacement of slope top is nonlinear with that of its lateral displacement; the increment of the ratio of vertical displacement to lateral displacement is linear with that of its lateral displacement, the alarm value of lateral displacement on the upper of soil nailing foundation pit is 0.8-1.0 percent of the excavation depth when slope instability happens

No.2 ventilation shaft of Qinling highway tunnel is one of the largest ventilation shafts in the highway tunnel field at home and abroad. Rock burst is a serious problem during the shaft excavation according to the analysis of in-situ engineering geological data. For evaluating rock burst tendency from the perspective of lithological character, the uniaxial compression deformation test and physical model test are carried out. There is a high tendency of rock burst in surrounding rock by analyzing the modified brittleness index and model test result, so it is essential to strengthen rock burst prediction and control. The initial stress field of surrounding rocks of shaft is regressively analyzed by 3D finite element method according to in-situ measured data by hydro-fracturing and distribution properties of in-situ stress. Then the comprehensive rock burst prediction and analysis based on Russenes and Tao criteria are made according to the induced stress field obtained by Kirsch solutions and in-situ stress distribution of surrounding rock of shaft respectively. The result shows that the weak and moderate rock burst will occur during shaft excavation. Finally, some countermeasures to rock burst are proposed. It provides valuable references for other projects.

The outstanding feature of soft ground in plateau wetland consists in peat bed of which engineering geologic condition is very weak. Based on the main features of soft ground in plateau wetland, using stone column and geogrid to treat the soft ground is an innovation. Based on FEM, the deformation characteristics and the mechanism of composite ground with stone columns and geogrid in plateau wetland are given. The results indicate that the stone column can expedite the process of drainage consolidation and enhance the bearing capacity of ground. The main effects of the geogrid are to restrict the lateral displacements and to dwindle differential settlements of the embankment.

By using finite element method，integrated simulation of whole process including temperature, seepage, stress and strain is carried out for Guangzhao RCC gravity dam. The results reveal the distribution laws of temperature field, seepage field and stress field. Based on the integrated simulation of whole process, the global safety degree of the dam-foundation system, which is important for the safety evaluation as well as the corresponding control measures of the temperature and seepage fields during the dam construction, is evaluated. The results are also compared by the conventional method and the integrated simulation of whole process for the Guangzhao RCC gravity dam, from which it is found that the largest displacement difference is 70 mm; the largest stress difference is 1.5 MPa; and there is no substantial difference in global safety degree. Since the deformation, stress and global safety degree are important indices in designing RCC gravity dam, the necessity of integrated simulation of whole process for RCC gravity dam is emphasized.

Based on the vector characteristics of forces, the vector expression of the safety factor in the vector sum analysis method (VSAM) is presented. In a slope with certain conditions, after determining the stress distribution with FEM, the critical slip surface can be searched with VSAM and the direct method in optimization algorithm. The calculated results show that the locations of the critical slip surfaces are in good agreement with the ones with Morgenstern—Price (M-P) limit equilibrium method, and the maximum relative error is only 2.09 percents between the safety factor obtained by VSAM and that by M-P method in calculated examples, which proves that VSAM is reasonable and reliable. At present, the methods with the safety factor of strength reserve are widely used in slope engineering; however, VSAM is different from the methods above。VSAM is clear in physics; the formula and its calculating process are very simple; and it will be easy to be applied in 3-D slope stability analysis. So VSAM can be widely used in practice.

Based on the in-situ survey of Erlangshan landslide and its controlling design data, a finite element program PCEP2D using contact elements, considering the interaction characteristics of anti-slide pile with prestress cable, is improved. Then, displacement, bending moment, stress distribution of contact elements along the pile are calculated. Moreover, comparing with traditional “m” method and monitoring data, it is shown that the engineering control effect of anti-slide piles is better.

Bolt is often analyzed as spar element with rough surface, which can only endure stress along the axial direction. But when it applied to jointed slope, it is more reasonable to consider both the axial and lateral effect of bolt due to the moving of joint plane. The models of mechanical characteristics with three springs and deformation characteristics are founded for bolt according to the theoretical analysis. In these models, the stress and deformation of bolt can be fully analyzed; in order to reflect the differences of dynamic and static displacements effect of jointed mass between the states of bolting and unbolting, the numerical calculation models of slopes are founded based on the perfect elastoplastic constitutive model, Mohr-Coulomb criterion, by numerical simulation technique of fast Lagrangian analysis of continua in 3D (FLAC3D). In the numerical simulations, the bolt element with three springs is applied. The analysis result shows that after bolting in jointed plane, the stiffness of rock mass is improved; the displacement of slope becomes smaller; the mutation magnitude of displacement beside joint plane becomes smaller; bolt system exerts the tensile effect for the upper and lower rock mass, and reduces the displacement in the joint plane, which is good to the slope stability.

Dynamic response of pipe piles under low strain transient concentrated load is a three dimensional wave problem. Based on the three dimensional wave theory, the computational model and wave equation of dynamic response of thin-wall pipe piles with variable wave impedance are established. Combined the initial and boundary conditions, the analytical solution of wave equation in frequency domain is obtained by Laplace transformation method. The time domain response is obtained by Fourier inverse transformation. By comparing the results of analytical solution with that of 3D finite element method, the following conclusions are achieved: the wave crest of the results of analytical solution can well meet that of the 3D-FEM results; and the displacement responses of them have little difference. The dynamic responses at different points on top of the pile and the high-frequency interference problem are also researched. The characteristics of dynamic responses of variable modulus piles and variable section piles are studied.

Integrated anchor system contains integrated bolt, full cement grouting and surrounding rock. In low strain dynamic response of bolt model, the action of cement grouting and surrounding rock on bolt can be considered as elastic and damping coefficients which distribute uniformly along bolt and stiffness and damping coefficients which distribute uniformly on the bottom section of it. These coefficients, named dynamic parameters, present anchorage quality, mechanical behaviors of surrounding rock are also presented. Based on the relationship between dynamic parameters of bolt system and physico-mechanical parameters of surrounding rock, the quality of surrounding rock can be identified. Three-dimensional axisymmetric calculation model is established by using finite element analysis. The velocity responses of bolt’s top with different physico-mechanical parameters of surrounding rock are obtained. A method to identify the dynamic parameters of integrated anchor system is established based on theoretical solution of integrated bolt’s dynamic response and genetic algorithm. The dynamic parameters of integrated bolt with different physico-mechanical parameters of surrounding rock are acquired; and the relation between bolt-side elastic coefficient and surrounding rock’s modulus of deformation is established. A method to identify the quality of surrounding rock through dynamic testing based on integrated anchor system is put forward.

The generalized regression neural network (GRNN) is introduced into the elastoplastic displacement back analysis in three dimension of Wushi tunnel in virtue of its merits, such as good approximation capability, fast learning speed and excellent network stability. In order to find the optimal threshold value of GRNN model during training course, the genetic algorithm (GA) is combined with it to form the GA-GRNN algorithm. After determining the optimal nonlinear mapping between the numerical model parameters and the displacements, GA is used to search the elastoplastic model parameters which can minimize the error between the calculation and measured displacements of Wushi tunnel. The parameters from back analysis are inputted into the GRNN model to forecast displacement of the next construction step; and the results are very close to the measured displacement. Therefore, it is concluded that this back analysis method is feasible in tunnel engineering and can be used in similar engineering.

The foundation soil is divided for finding the ultimate bearing capacity of a foundation with given buried depth and size. Supposing a uniform load acts on the foundation, Mindlin’s integral formula and corner points method are used to get extra stress of every mesh knot by MATLAB program, then the principal stress is found. Combining with failure criterion, MATLAB program is used to find coordinates of points which are destroyed. Using graphic processing function of MATLAB, the failure points are showed in the coordinate. Increasing the rectangular uniform load, the failure points are found until these points can form a continuous failure surface. This rectangular load is the ultimate bearing capacity of the foundation. The method can avoid errors brought by unreasonable hypotheses of the empirical formulas; and the three-dimensional failure surface of the foundation soil is obtained.

Reliability analysis methods based on probability is proposed for analyzing slope stability to overcome the shortcomings caused by using safety factor as the standard of slope appraisal. For each given slip surface, an optimization model is suggested combined with Lagrange multiplier method. Genetic algorithm (GA) is adopted to search for the key slip surface, and a fitness function is proposed. According to the disadvantages of standard GA, the global and local research abilities can’t be controlled in the optimization process; the method of determining the best individual in offspring is improved, and the probabilities of crossover and mutation are adjusted dynamically guided by the increment of diverse characteristic value to assure population diversity and search validity. The results show that the search ability and convergence speed are improved, and the global optimal solution is guaranteed by the proposed method; the method is suitable for analyzing the reliability of slope stability with simple pretreatment; computational complexity of GA can be reduced greatly and much calculation time can be saved if computational model of reliability index is pre-optimized before GA performance.

Some very precious professional test apparatuses are needed conventionally to determine the adiabatic temperature rise of concrete and the thermal diffusion coefficients of concrete surface. These apparatuses are very expensive and there may be errors in the test results due to different environmental conditions between laboratory and site. In view of this problem, based on the 3-D FEM of nonsteady temperature field and the genetic algorithm of inverse problem optimized solution, non-adiabatic temperature rise test of concrete cube on construction site is carried out to distinguish and ascertain concrete thermal parameters, including heat exchange coefficient, adiabatic temperature rise and law coefficient of adiabatic temperature rise. The results show that these parameters can indicate the real thermal properties of concrete in site. As one kind of optimization method, the genetic algorithm is simple and universal with good adaptability and high efficiency.

Jinchuan No.3 mine area is taken as a study object. Based on the field investigation of discontinuity parameters, by adopting Monte Carlo simulation method, a synthetic database of discontinuities is generated. The ore fragmentation for block caving is predicted by determining the number of discontinuities that form a block, establishing the equation of the discontinuities in the 3D coordinate system, determining the actual vertices and the coordinate of each vertex, and the volume of the block is measured; the characteristics of the block shape are identified. The ore fragmentation has a direct influence on the configuration of stope bottom, the selection of loading and handling equipment, secondary crushing method, the estimation of explosive consumption and so on. The simulation results show that the fragmentation with equivalent size of more than 0.9 m account for 38.2 per cent and those more than 1.3 m account for 17.2 per cent of the total fragmentation volume.

The underdrain of ancient canal beneath Shi-Tai Expressway is a large-scale graff cross structure of main channel in middle route project of South-to-North water diversion. This underdrain is three-arch culvert structure, where construction condition is very complex. The soil of underdrain constructed using partial excavation method are fine sand and medium-fine sand mostly, and passing vehicle load on expressway is heavy; so the construction is the most difficult one and the excavation width (25.6 m) is the widest for similar domestic engineering. The construction process according to actual construction sequence and craft is simulated by using FLAC3D software. The stratum deformation, the stress and the distribution of plastic region are discussed in detail. The calculation result indicates that the underdrain construction scheme of underpass is reasonable; and it has guidance function on the underdrain construction scheme of underpass; and it also provides basis for the range of stratum reinforcement. The practice of construction process verifies that the assistant reinforcement measures are effective for the safety of railway lines and tunnels based on the results of numerical simulation.

The matrix form of Newton-Raphson incremental solution at the k+1 iteration is updated based on the finite deformation theory, leading the finite element implementation to the simulation of the deformation band in the fluid-saturated sand, and the criteria for localized deformation under drained and undrained conditions are derived and utilized to detect instabilities. The spatial discretization of the displacements and the pressure fields are furnished by the classical Galerkin method; according to the continuity of tractions across the deformation band, the necessary condition for localization is obtained by introducing the first tangent operator. Based on the algebraic manipulation above, a finite element numerical computational program is coded by FORTRAN; and then numerical simulations on saturated sand under undrained condition is performed to study the onset and development of the shear band. Also, the mesh sensitivity is studied; and the results show that the pathological mesh dependence is mild, which is related to the apparent width of the shear band, while the different meshes display the same overall mechanical behavior.

The bearing capacity and load transfer behavior of a single T-shaped deep mixing column are analyzed by 3-D numerical simulation based on field test. The results indicate that when other parameters stay the same, the ultimate bearing capacity of a single T-shaped deep mixing column increases with the height H and diameter D of enlarged column cap; but the ultimate bearing capacity of unit cement volume increases with H/L and D/d at first to the maximum, and then decreases; where L is pile length, d is pile diameter. There is critical column length of T-shaped deep mixing column on bearing capacity. Most of the column load concentrates on the enlarged column cap which is the main bearing part of T-shaped deep mixing column. As the effect of enlarged column cap, the column load at the variable section attenuates greatly. When other parameters stay the same, the axial force and side friction of lower T-shaped deep mixing column are larger than those of conventional deep mixing column under their respective ultimate loads.

Tectonic stress analysis is particular important in the course of petroleum exploration and development. The geological structure complexity, its boundary problem, the loading paths, etc. are difficult problems in the numerical simulation of tectonic stress field; and the field stress data is very limited. Because of the unknown tectonic movement and complicated geological structure, tectonic stress field cannot be calculated immediately. The boundary load inversion is a particular important means for tectonic stress field analysis. Starting from the fundamental equations of elastic mechanics, the inverse problem of tectonic stress field of oil-gas reservoirs is proposed. Based on the least square method, a method is presented to identify and calculate inversely the boundary load on the geological model by the stresses in the geological model. The finite element method and the finite difference method are combined to apply the method that chooses the boundary loads as fitting parameters in the objective function. The calculated results are in good agreement with the in-situ measured data. This method has excellent practical value and can provide references to the back analysis of tectonic stress field. This method and model can get over the shortage of common back analysis method such as adjusting boundary loads and regression method; so it can calculate exactly the tectonic stress field by back analysis. The results show that the method is simple, credible and has high precision and rapid calculation velocity. Therefore, it may find its uses in the boundary load inversion of tectonic stress field. This method can provide references to petroleum exploration and production.

The importance of long-term on-line monitoring sea dyke subsidence is described. An experimental system, which monitors Shanghai Lingang sea dyke section k3+640 and k3+780 using distributed Brillouin optical fiber sensing technology (BOTDR), is introduced. The monitoring data from optical fiber sensor system and traditional leveling observation are compared; and the position of the largest strain coincides with the position of the load. The subsidence distribution is calculated; and it coincides with on-site load status and the result of leveling observation. The maximum deviation of five in-situ observation points is 94 mm; the average diviation is 39.2 mm.

In order to guarantee the operation safety of the metro above during the construction of Chongwenmen station in Beijing metro No.5, the remote monitoring system is used to measure the dynamic changes of existing metro structure. The monitoring system is composed of sensor subsystem, data acquisition and transmission subsystem, and data management subsystem, which can reduce the interaction between the monitoring and subway operation in maximum. The sensor subsystem consists of static force level gauge, beam inclinometer, displacement sensor and joint meter, which are used to monitor the settlements of existing tunnel and track bed, transverse height difference and horizontal space between two running rails and changes of the structure slots respectively. The data acquisition and transmission subsystem can transfer the collected data to the information center by wired medium. The data received will be treated by the management subsystem; and then fed back to related departments and companies by public network. The deformations of the existing metro structure are monitored effectively by the system during the undercrossing construction of newly-built metro station; and the control measures are adjusted in time according to the deformation data so as to make the existing metro runs safely.

Semi-rigid base course materials are widely used in the high-class highways in China. If shrinkage strains of semi-rigid base course materials caused by the variations of temperature or/and moisture exceed the ultimate tensile strain that the material can bear, it will fracture, and the service performance of the pavement will be influenced. Choosing suitable shrinkage test method to study semi-rigid base course materials’ shrink performance has high practical significances. For the shortage of the conventional shrinkage measuring method, the lab shrinkage experiments on a kind of typical cement stabilized macadam are studied by the digital image correlation method(DICM), the early change laws of shrinkage strains are analyzed; by calculating correlation of the images captured before and after deformation, DICM is employed to obtain the whole-field shrinkage deformation. Comparing with the conventional shrinkage test results, the repeatability is fine, the stability is good and the accuracy is higher.