By utilizing the Shanghai Mid-ring Line-Beihong Road underground intersection traffic tunneling project which was constructed by using the pipe-roofing and large section box-culvert jacking trenchless excavation technology, as an engineering background, the authors give a systematic study on the numerical simulation of ground movement in the whole construction process of above-mentioned project by using the ANSYS&FLAC 3-D computer programming respectively. Secondly, by adopting the elastic foundation beam method, lab.-model experiment, and actual test data analogical techniques in situ separately, the authors give a comprehensive study on characteristics of the ground movement variations developed in construction of the large section box jacking with pipe-roofing trenchless techniques. Finally, as adopting the intelligent soft science method, the authors make a so-called “multi-stepped rolling” prediction study by using artificial neural networks (ANN) on surface ground settlement increasing with time around the project. The results have been provided to the design and construction companies for a valuable reference.

Element integration method provides a general approach for slope stability analysis based on the upper bound limit theorem in plasticity. Small triangle elements are used to discretize the slope media. A kinematically admissiable velocity field is supposed independed with the element meshing. Work done by the body forces, surface loads, as well as internal energy dissipations within an element are convenient to obtain under such a failure mechanism. The whole energy can be calculated from the energy integration among all the elements. The safety factor can therefore be solved from the upper bound limit theorem, and its minimum value can be obtained from optimization method. For single block mechanism, such as plane slip surface, or log-spiral slip surface, the validity of this method has been verified from three typical examples.

The theory of complex variables methods and multi-polar coordinate systems are used to solve the problem of scatter and dynamic stress concentration of elastic waves around double elliptic cavities in saturated soil. The 2D steady state Biot wave equations are decoupled by introducing the potentials and reduced to three Helmholtz equations that the potentials satisfy. The solving of the Helmholtz equations by separating variable methods obtains general solutions of the potentials. The expressions of displacements, stresses and pore pressure can be obtained by determining the unknown coefficients in the potentials and utilizing the boundary conditions of soil and pore pressure. Numerical examples are provided to show the effect of wave number, distance between centers of cavities upon the dynamic stress concentration and pore pressure concentration around the cavities under incident steady elastic wave.

Based on according completely with practical constitutive relation of rock, i.e. relation between stress and strain that is linked glossily by three segments composed of elastic, strain nonlinear hardening and nonlinear softening segment having inflexion, the stress distribution laws of surrounding rock in plastic hardening and softening zone of circular tunnel under the condition of hydrostatic pressure is deduced. It is proved that the obtained radial and tangential stress curve link glossily at hardening zone radius and softening zone radius , and curve of tangential stress - has not up-pinnacled stress concentration especially, the result goes all the way with the experiment result of Japanese scholar Jiuwubosheng. The paper points out that there is obvious limitation in Kastener formula based on ideal elastoplastic constitutive model, and up-pinnacled stress concentration of - doesn’t correspond with practice.

The large amount of CO2 emission as a result of excessively relying on the fossil energy leads to global warming. CO2-ECBM(CO2 enhanced coal-bed methane) is an attractive way of enhancing CH4 recovery and sequestering CO2. When CO2 replaces CH4 in the coalbeds in ECBM(, it will generate dramatic swelling. This paper addresses the influence of the swelling on the casing stability. Consistent results are gained using the analytic model proposed by the authors and ABAQUS simulator. Swelling of coal can bring dramatic impact on the casing stability. Based on the analysis of the impact factors of casing stress, it can be concluded that the casing stress can be obviously weakened by promoting the wall thickness of the casing or by using the filling material of very high Poisson ratio and Young’s modulus

The uplift of underground structures in liquefiable soil due to earthquake induced liquefaction may lead to severe damage. The use of cutoff walls is believed to be an effective approach in diminishing the uplift, but its mechanism is still not clear, and the design parameters of the cutoff walls also deserve investigation. Effective stress based dynamic finite element method was used in the efforts to clarify the mechanism as well as the influences of different design parameters of the cutoff walls. It was found that cutoff walls could reduce the liquefaction-induced uplift of underground structures to considerable amount. After looking into the excess pore pressure, soil deformation, stress path as well as stress-strain relationship, the effects of the cutoff walls were identified as reducing the deformation and flow of the liquefiable soil. Although the cutoff walls could decrease the excess pore pressure at small earthquake excitation; but during large earthquake, the excess pore pressure was larger for the cases with cutoff walls. The reasons were identified and explained. The important design parameters including the location, embedment length into the non-liquefied soil, and the lapping length with the underground structure, were investigated. In order to be effective, the cutoff walls must be located as closely as possible to the underground structure; they also need to be embedded in the non-liquefied soil with sufficient length; and their stiffness must be higher enough.

Natural soils usually exhibit initial structure and anisotropy. The strength and deformation of natural soils normally differ from those of the remoulded soils under complex stress path. The mutual effects of the structure, initial anisotropy and complex stress path make it complicated and difficult to determine the progressive destructive strength and parameters of natural soils. The analytical solution to the progressive destructive normalized undrained strength of anisotropic natural soils is derived. The dependency of the progressive destructive normalized undrained strength of natural soils on the initial anisotropy, progressive destruction ratio and stress path is investigated.

For the engineering rock mass media of soft rock tunnel has been in the plastic and large deformation stage and its deformation and fail are caused by the un-coupling between support and surrounding rock, a nonlinear mechanics design method of bolt-net-anchor coupling support is put forward; and it includes deformation design, strength design and feedback design. This design method is different from the classic design method, it is the parameters design. The coupling support parameters of bolt-net-anchor got by strength design are based on the optimum coupling procedure got by deformation design, and can be modified by feed back design in the supporting period of tunnel. Different from the new Austrian tunneling method, using this design method can realized the coupling on the strength, rigidity and structure between support and surrounding rock by bolt-net support interior surrounding rock and anchor to mobilize the intension of exterior rock.

The failure process of plane strain two bodies model composed of rock specimen that is always elastic and coal specimen that is elastic prior to the peak stress and strain-softening beyond the peak and the effect of height of rock specimen on the complete stress-strain curves of model and coal specimen, the deformation rate and failure mode of coal specimen as well as the shear strain increment within coal specimen were numerically modeled by FLAC under the condition of smooth ends (no end-restraint effect). Numerical results show that when the peak stress of complete stress-strain curve of model is reached, the pattern of shear bands within coal specimen is very apparent. In strain-hardening stage of model, strain localization of coal specimen can be seen as a precursor to the unstable failure of model. Longer rock specimen leads to (1) steeper strain-softening branch of stress-strain curve of model, as is in qualitative agreement with the previous analytical solution that longer specimen results in steeper post-peak stress-strain in uniaxial compression; (2) more ductile strain-softening branch of stress-strain curves of coal specimen and higher plastic dissipated energy consumed by coal specimen; (3) lower deformation rate of coal specimen in stage elastic; and (4) higher shear strain increment within coal specimen. The slope of complete stress-strain curve beyond the peak stress of coal specimen, the deformation rate of coal specimen in stage elastic, the shear strain increment within coal specimen and the plastic dissipated energy consumed by coal specimen are influenced by the height of rock specimen, which reflects that the effect of geometrical size of rock specimen on the deformation and failure of coal specimen and the interaction between coal and rock specimens cannot be neglected.

The risk analysis system of regional debris flow hazards is briefly discussed; and some mistakes on the study of hazards analysis of regional debris flow and difficulties on the assessment of social economic vulnerability are indicated. By means of the conception of “hazard entropy”, a new approach for quantitative risk analysis of regional debris flow hazards is brought forward. A risk assessment matrix is built up through grading the hazards of regional debris flow and the social economic vulnerability. On the basis of risk assessment matrix, the risk of regional debris flow is graded; and it will lay a solid foundation for effectively early-warning of regional debris flow and reducing and preventing hazards.

The aseismic performance of shallow buried water-conveyance tunnel in soft soil area is becoming more and more important with the development of large-scale water conveyance projects. In the big diameter water-conveyance tunnel, on account of large mass and sloshing of inner water under the vibration, which will bring water－tunnel lining interaction. All the above will affect dynamic response of tunnel lining. Aiming at this problem, the paper studies water-conveyance tunnel by dynamic fluid-structure coupling method. Especially, inner water is modeled by potential-based liquid element. The numerical results show that the inner water has great effects on the frequencies and dynamic response of water-conveyance tunnels.

The failure procedure of a rock borehole structure is experimentally studied using a specially designed deformation field inspection system (Geo-DSCM system). The borehole specimen, which is manufactured by drilling a hole at the center of a marble plate, is uniaxially compressed to failure with the speed of 0.02 mm/min. Deformation fields through all the loading procedure are inspected and analyzed. It is shown that the deformation field localizes on the sections in tension at the early stage of loading.. While when specimen is loaded almost to the peak of loading curve, two new X-shaped localization bands, which are at angle from the loading direction, occurred. Finally only one localization band maintained and formed the macro fracture that failed the structure.

Xiaolangdi Key Water Control Project is located at the Yellow River; it has comprehensive effects of flood control, water supply, generating electricity, etc. Its underground powerhouse caverns belong to large-scale type and have a buried depth of 70-100 m. The process and method of numerical analysis was introduced, including: rock plastic yielding criteria adopted; three-dimension geometrical model; rock mass mechanical parameters; initial earth stress field; excavating process simulating method; sustaining structure simulating method. Calculation results of three cases under conditions of two earth horizontal stress coefficients 1.0 and 0.8 are given. The three cases are: (1) having no sustaining structures; (2) having rock bolts and concrete lining but no pre-tensioning cables ; (3) having pre-tensioning cables and rock bolts and concrete lining. Several conclusions of this study are drawn as follows: (1) the sustaining structure has not significant effect in limiting rock displacement and plastic area, but has an indispensable role in fixing loose and broken rock pieces and preventing partial rocks around caverns from falling; (2) excavating process has little influence on pre-tensioning cable force; (3) excavating process causes great tension stress in concrete lining; and the steel-net on rock surface has important effect on confining lining cracking and preventing lining from falling.

The researches on rigid piles were mostly focused on their bearing capacities; and few people studied their deflections. So a method for determining rigid pile positions is put forward; and thus the displacement of any point on pile, the position of rotation center and the deflection angle of rigid pile can be obtained from the lateral displacements of any two points on rigid pile. The rigid piles embedded in silty clay are tested and analyzed numerically. It is found that the rotation center falls sharply firstly, then descends slowly and finally tends to be stable with displacement and load. Embedding parameters of piles and mechanical parameters of soil have few effects on the varying laws of the position of rotation center with lateral loads. The deflection angle of rigid pile increases linearly with loads on the whole. By comparison, it is found that the ultimate positions of rotation centers obtained from test and numerical analysis are consistent basically with those from some limit subgrade reaction methods.

The changing laws of electromagnetic emission (EME) and acoustic emission (AE) during the deformation and failure of the coal or rock sample under uniaxial compression are studied experimentally. Then the energy transformation relation between EME signal and stress fields in the course of deformation and failure of the coal or rock is researched on the basis of experimental testing results. The research results show that: the intensities and pulse of EME and AE will increase with the increasing of loading time or stress and the enhancement of deformation and fracture; the relation between the EME intensity, pulse numbers and the loading stress is positive; the EME value will decrease after the summit value; the changing curve between EME energy and mechanical energy is consistent with the relation curve between stress and strain, which conforms to thrice multinomial approximately; so it is feasible to study the relation between EME and stress during deformation and fracture in view of energy transformation.

The problem of flexural deformation and failure of the roof of laneway is prominet when a laneway is excavated in horizontal layered rock mass. Customarily, the deformation of roof is so large that it failures first and thus leads to the whole structure collapse. According to its special characters of flexural deformation and failure mechanism, the authors write a program with Matlab based on cosserats’ theory. By using the program, the deformation character and influencing factors are studied. The result indicates that the cosserats’ theory is suitable to simulating the laneway excavating in layered rock mass; and it is simple and convenient.

Contact element is combined with slope stability problem and a new calculation method of slope safety factor is put forward based on partial failure theory. The computation result obtained by new method is very closed to that of the traditional method, which illustrates that the new method is feasible and correct. Therefore, it is further proved that local failure theory is correct and weak structural plane will control the stability of slope.

Based on the former achievements and the known basic dynamic property of fly-ash dam, earthquake response tests of Ⅵ and Ⅶ degrees simulation earthquake waves and failure tests have been done on the models of fly-ash dams with different dam crest elevations of 170, 180, 230 m by the large-scale shaking table. The earthquake resistance tests have been done on the models of ash dams heightened by three mixtures of ash and corresponding evaluations are given. The conclusions are beneficial to the research of earthquake resistance of ash dam and the earthquake attenuation and disaster prevention.

Based on perfectly elastoplastic constitutive model and Drucker-Prager yield criterion, the rock mechanics theory, the numerical simulation technique of FEM and the strength reduction principle are used to simulate and analyze the stress, displacement, friction on contact surface and the stability of bedding rock cutting slope in different excavated stages. The analysis indicates that the stress field, displacement field, contact status and stability of the bedding rock cutting slope are obviously influenced by excavating effect. On each excavated face, the horizontal displacement near the slope toe is the biggest; the most dangerous contact surface focuses on the excavated slope toe where the abscission destruction firstly occurs. Also, the safety factor of the slope gets lower gradually as the slope is excavated deeper.

The indoor model experimental study on the physico-mechanical properties of pavement with weathered gravelly sands and argillite slate rock as the express railway embankment under quasi-static cyclic loads is introduced. Based on observations of some experiments, using biggest dry density and the optimum moisture content in its filling, the physico-mechanical properties including the moisture content of water, dry density, porosity ratio, angle of internal friction, cohesion value, displacements, stresses, permanent deformations, pressure distribution, bedding coefficient K30, deformation modulus Ev1 and deformation coefficient Ev2 of the embankment etc.,are obtained. With constitutive model for Drucker-Prager material, the stress and deformation characteristics of the pavement under quasi-static cyclic loads are analyzed by using finite element method. The numerical solutions are close with experimental ones. It is expected to put into use for design of pavement, control of compaction quality and construction in subgrade filling engineering.

In Harbor Engineering, it is often the case that subsoil consists of layered soils. In China, Hansen 61’s methods、Hansen 69’s methods and developed Sokolovski methods were recommended by the code to estimate the ultimate bearing capacity of layered foundation. However, in practice the ultimate bearing capacities of layered foundations predicted by the three methods are different from each other. Considering inherits of the codes, a calculation program has been compiled using Newton iteration methods to solve the expressions presented in the codes. Then, basing on the geotechnical information in the Yangtze River mouth region, the ultimate bearing capacities of layered foundations have been computed by the program and the predictions from three methods have been compared each other. The results show that under the same geotechnical conditions and similar loading conditions, the developed Sokolovski methods shall provide the largest bearing capacity values among three methods; while the bearing capacity value from Hansen 69’s methods shall be smallest.

The interaction of two level parallel pipe jacking is analyzed; and the calculation of lateral disturbance scope is advanced. Considering the effects of former pipe jacking on the latter, a new calculational method for ground settlement of latter pipe jacking is put forward with an analytical calculation example. It is shown that the ground settlement produced by middle zone is greater because of double disturbance during parallel pipe jacking construction. Also, the surrounding soil disturbance due to former pipe jacking construction will strengthen the disturbance during latter pipe jacking construction when the axes of two pipe jacking are in close quarters. Thus, the maximum ground settlement and width of settlement trough during latter pipe jacking construction become greater. In addition, curves of ground settlement are dissymmetric for latter pipe jacking and can still be calculated with Peck formula. The maximum settlement point on curves leans towards the side of former pipe jacking.

In order to simulate the fines content effect on the liquefaction properties of tailings, the tailings were sieved and then were mixed according to different fines contents to prepare samples. Based on a lot of dynamic tests of these tailings samples, the effect of fines (d < 0.074 mm) content on the dynamic liquefaction of tailings was analyzed in detail. The study result has shown that when the fines content is about 35 %, the liquefaction resistance of tailings is the best. Based on the dynamic experiments and lots of standard penetration tests in situ, a modified formula is presented to take the effect of fines content on liquefaction properties into account. The modified formula can analyze the effect of fines content on the liquefaction resistance of tailings material. Consequently, the modified formula can evaluate liquefaction strength of tailings material more accurately.

The equivalent static analysis is Bishop’ total stress analytical method, which is recommended by Chinese Specifications for Seismic Design of Hydraulic Structure. Because of thinking no influence of the pore water pressure of inter-slice in static and dynamic state, the calculating results tend to unsafe. It is applied at analysis of pore water pressure of inter-slice which are the static distribution of pore water pressure based on FEM of static seepage field and dynamic pore water pressure increment in the light of dynamic liquefaction FEM analysis. A modified effective analysis method of equivalent static analysis is suggested. The computing result is satisfied in the dynamic stability analysis of a tailings dam.

The process of the projectile penetrating into plain concrete is numerically simulated with the BPM2D (beam-particle model in two dimensions). The discrete element method (DEM) and the finite element method (FEM) have their own advantages and weaknesses. Basically, the DEM was developed for predicting the failure problems accompanying with the transition from continuum to non-continuum media. However, it is not accurate to calculate the problem of continuum media. The FEM may forecast the failure area of the material reasonably, while it is hard to calculate the failure process in brittle media. Therefore it becomes a good choice to combine the two methods to construct a hybrid model. The BPM2D is presented on the basis of the DEM and the FEM. Three types of beam in the BPM2D have been used to form numerical model of concrete. The mechanical properties of every type beam vary with their strain-rate and are randomly allocated according to Weibull distribution to reflect the initial heterogeneity of concrete at the mesoscale level. The failure process of the projectile penetrating into concrete is discussed. It was displayed that the deceleration history of projectile in penetrating. The comparison of the simulation results with the experimental data shows that the BPM2D is applicable to simulate the dynamic failure problems of brittle material.

Based on the investigation of the strength characteristics of seabed in front of a bank and nearby area in a section scale, the dynamic response of silt seabed was studied in the Yellow River estuary beach. It was found that the relative hard strata not only formed horizontally but also vertically; and the vertical stratum has a relationship to the hydrodynamics. Through the impact loading and model analysis, a conclusion is drawn as follows: the formation of seabed sediment consolidated inhomogeneity is due to the fine particles flow under wave loading, when the fine particles accumulate, the sediments will become harder for the perspiration of pore water pressure; thus result in the inhomogeneity of silt seabed.

Stone column is composed of broken stones, among which the interconnections are very small. Thus the mechanical characteristics of broken stones depends on their densites and lateral pressure mainly. The deformation characteristics of broken stones are studied by the large scale triaxial shear tests and axial compression tests, the laws about broken stones are drawn according to the test results as follows: the relationship between the deviator stress and axial strain is close to a hyperbola and the relationship between the volume strain and the axial strain is similar to a parabola for the triaxial shear tests; the relationship between the axial stress and the axial strain are near to a power function curve for the axial compression tests. The test for the composite foundation of stone columns of Xu-Su Expressway is described in detail. The results show that the liquefaction potential has been eradicated when the stone columns are used to treat the soil foundation of this area. The tests and results have a referential value to the similar engineering problems.

The deficiency of Duncan-Chang model in analyzing the stress of the loess surrounding the compaction pile is pointed out. Based on this analysis, the laboratory soil test is conducted and the compaction principle of the loess surrounding the pile in the loess region is analyzed; the above analysis leads to a conclusion that modulus of deformation accords with Duncan-Chang model before the loess surrounding the compaction pile failing and to be determined by modulus of compressibility of remolded sample compression test and suggested coefficient ? after failed. Then, a loess compaction model is suggested and verified through an example. The model sets a solid foundation for the future stress analysis of the loess surrounding the pile and has reference value to perfecting design theory of the compaction pile.

Soil shear wave velocity is an important parameter of earthquake engineering. Classification of engineering site sort, reassessment of saturated sandy soil liquefaction and subsoil earthquake response analysis all depend on subsoil shear wave velocity. An optimized approach for single-hole method of shear wave velocity measurement is presented. The approach overcomes main irrationalities of minus velocities, over-large and over-small velocities and large velocity differences among measuring points in the same layer of traditional analysis method, improves the data processing precision and efficiency of single-hole method.

The multifractal of the structural planes in rock mass of dam site area of the Yujianhe Reservoir in Guiyang, the capital Guizhou Province, is studied. The results of measurement and statistics of the structural planes in rock mass are applied to study multifractal. At first, multifractal for structural planes is studied using selected area in Area A. Different unit measure in different unit is selected to divide the studied area into squared unit mesh. And then, suitable different real number values are chosen, scale index is gotten using linear fitting method; their relation is obtained. Multifractal dimension, singular index and multifractal spectrum values are obtained using related formulae. Finally, multifractal dimension values, singular index and multifractal spectra values in other areas are obtained using the same method and contrasted. Its results show that the maximum values and average values of multifractal dimensions, singular indexes and multifractal spectra values are in Area A greatest in all selected areas. It shows that the structural planes in rock mass of Area A are complex and inhomogeneous; its engineering property and quality of rock mass are poorer. And the order of arrangement in good and poor quality is given according to the results of multifractal.

In order to study the causes of post-construction settlement of deep-jet-mixed(DJM) pile composite foundation at bridge approaches, the settlement is analyzed and back-analyzed by Biot’s consolidation FEM. The soil constitutive model is the Duncan-Chang nonlinear elastic model in finite element analysis; and Duncan-Chang nonlinear elastic model and Merchant viscoelastic model are used in finite element back-analysis. The computation results show that the traffic load and soil creep are the main causes induced the post-construction settlement of DJM pile composite foundation. The traffic load is the main cause at early period, but soil creep is the main cause at post period.

For the complex topographical tailings dam, neither the complicated and changeable seepage field nor the action of three direction seepage factors at the same time can be fully reflected in the two-dimension model; as a result the real seepage field cannot be acquired. A three-dimension mathematical model is set up; and both section and terrain are simplified. An example is given; and the result is compared with that of the test .The better identical result indicated that the three-dimension model must be adopted in the seepage analysis of the complicated topographical tailings dam; and the appropriate predigestion can satisfy the precision and reduce the complicity and difficulty.

It is important to evaluate the interaction between the twin large tunnels in close space to facilitate its economical and safe design and construction. The paper mainly involves the field monitoring on interaction between the twin large diameter slurry shield tunnels in close space—East Fuxing Road Tunnels across the Huangpu River. Firstly, it introduces the origin and background of the subject, the engineering situation. Then, it introduces the field monitoring including horizontal displacement of deep soil, settlements of ground surface and deep soil, three-dimensional displacements and deformation of the north tunnel, the water-soil load acting on the north tunnel, internal force of the north tunnel, the excess pore water pressure in soil. Through analyzing the field monitoring data, the rule that the constructing shield affects the settlement of ground surface, the displacement of deep soil, the excess pore water pressure, the displacement and deformation and internal force of the existing tunnel, are obtained. Obviously, the interaction is very more than estimated. And the actual internal force could be much than the adopted for the design.

In light of the problem of describing nonlinear rheology of rock and soil with principle of linear superposition, a neural network model for rheology of rock and soil under step loading has been established with artificial neural network instead of traditional mathematical and mechanical methods. By simulating the experimental creep curves of gypsum breccias, it is shown that the model can effectively describe nonlinear rheology of rock and soil with better prediction. This approach provides a new way for studying rheological properties of rock and soil especially nonlinear rheological properties under step loading.

Based on different conditions of climate and landforms, the mathematic models of seepage in farm drainage are used for drainage inside roadbed of expressway; and the seepage model without considering rainfall, seepage model with considering lasting rainfall, seepage model after stopping rainfall, seepage model with phase rainfall of full blind drainage and their analytic solutions are studied emphatically. It has been proved by engineering cases that the drainage design with seepage model is reasonable so as to provide definite experiences for drainage design of blind drain inside roadbed of expressway in the West China.

The consolidated undrained triaxial shear test is carried out on unsaturated undisturbed loess (Q3) in the case of moistening. According to the test results, the relation curves of ultimate strength of collapsible loess and initial moisture content and confining pressure are obtained; and the shear strength characteristics of loess during moistening process are analysed. It is concluded that the strength envelope of unsaturated undisturbed loess under original moisture content is composed of two beelines. However, the strength envelope under high moisture content still follows Mohr-Coulomb criterion. The cohesive force of unsaturated loess is decreased significantly with increasing initial moisture content, but its internal friction angle is affected slightly by the change of initial moisture content. With the increase of initial moisture content, total stress indices are always smaller than corresponding effective stress indices. It is found that the relation between effective cohesive force of unsaturated loess and initial moisture content can be exactly fitted with exponential function. Finally, the influence of initial moisture content and confining pressure on shear strength indices of loess is analyzed briefly

Based on geological investigation and rock and soil experiments, the engineering geological characters of aubergine mudstone (T2b2) is studied synthetically. The mineral component and microstructure of the mudstone are determined. The physical and water-physical parameter of the mudstone is tested. Based on the disintegration test under different water contents, the stronger disintegration character of the mudstone is observed. The disintegration is nearly related to the physical state of rock. With the indoor test, the mechanical parameters and deformation character of the rock mass are obtained. With the point load test of the mudstone under different weathering degrees and different physical states, the engineering geological characters of mudstones with different weathering degrees and the influence on engineering construction are analyzed.

A new support system is applied to excavation of double foundation pits. In this system, double large-diameter annular arched girders structural system is used. By construction monitoring in Tianjin Cause Bay Plaza, data about internal force of supporting system and horizontal displacement of soil are obtained. This article analyzes these data and also discusses the characteristic of internal force changing in annular arched girders and influence on environment in the course of excavation. By these analyses, the law of horizontal displacement in ambient soil is drawn; and the measures considering the construction factors can be adopted for the annular arched-girder structure design.

Long-term researches have now indicated that the roadbed project is one of the key factors of the Qinghai-Tibet Railway which have close relationship with whether the project successful or not; frozen soils are the key problem of the roadbed project in cold regions. In order to protect the permafrost under the railway roadbed, prevent the inhomogeneous deformations induced by frost heaving and thaw collapsing of the frozen soils under the roadbed, we carried out the embankment filling grading and reconstructing local experiment research, embedded the frozen soil settlement drill monitoring instrument. We have accomplished the plate loading test to study the bearing capacity of the grading and reconstructing local experiment roadbed and the reliability of the inbuilt settlement monitoring instrument. Results show that it is reasonable to regard the soil of the experiment as isotropic, continuum and elastic substance. Based on this mothod, the calculated settlement of the experiment roadbed is in accord with the monitoring result, high quality and reliability of the settlement drill monitoring instrument had now been testified.

Applying the methods of stable isotopes and hydrochemistry to study the leakage of dyke is an effective way. But men only qualitatively analysed and judged the problem. The authors attempted to perform the analysis of fuzzy clustering by applying fuzzy clustering method that stable isotopes and hydrochemistry values of 22 water samples were taken as index characteristic values and endued different weightings, combining the case of Beijiang Dyke. The clustering result shows that there is great interrelation about stable isotopes, Cl- and TDS among the water samples of T12 borehole, water gushing at 5m north to T9 borehole, river water and out-waters of drainage gallery north to T9 borehole. It is a proof to judge the leakage passage that the water samples may has the same replenishment source.

When we use the ground penetrating radar (GPR) to detect the effect of grouting behind segment at the shield tunnel tail, it is very important to ascertain the velocity of electromagnetic wave (EMW) to obtain accurate results. It is unrealistic to assume that permittivity and electric conductivity are invariable, when the velocity of electromagnetic wave was estimated. In order to assure the precision of GPR image identification, network analytic instrument is firstly introduced to detect the dielectric permittivity of grouting material under the different frequencies, mixture ratios and curing periods. Some direction deduces analyses based on radial tracing theory have been done and compared with the results of the same grouting material on the site. This study shows that it is very necessary to adopt the different dielectric permittivities according to the different frequencies and curing periods.

Deep soil movement monitoring is a very important task during the excavation and sustainment of large foundation pit. Brillouin optical time domain reflectometry (BOTDR) is a newly developed distributed measurement technique with characteristic of distribution, long distance and duration. It has been used to monitor the structure deformation and temperature. In this paper, the principle of the BOTDR was introduced firstly; and then an experiment was given to study the feasibility of applying BOTDR to foundation pit monitoring. In laboratory the deformation of inclinometer tube was measured by BOTDR through the sensing optical fiber bonded on it; and the measured results were contrasted with ones measured by strain gauges. It’s shown from the comparison results that the strain measured by BOTDR is consistent with that by strain gauges. The successful application of the method introduced here into practical foundation pit monitoring demonstrates the feasibility and effectiveness of the method.