Up to now the influences of temperature field and stress field on the migration of radioactive nuclide with groundwater have been studied rarely. Against this problem, the elasto-plastic model and the relative 2D FEM code have been extended and improved for analysis of coupled thermo-hydro-mechanical processes in saturated-unsaturated porous media developed by introducing percolation and migration equation, so that the code can be used for solving the temperature field , flow field, stress field and nuclide concentration field at the same time. Then a computation example of an assumed nuclear waste repository, in which different values of permeability, distribution coefficient and molecular diffusion coefficient of buffer material are used respectively, the distributions and changes of nuclide concentration in the near field are investigated under the condition of coupled thermo-hydro-mechanical-migratory. The results show that the transport of nuclides in buffer are not influenced by the flow field nearly when the permeability of buffer is low to a certain extent; the less the distribution coefficient and the greater the molecular diffusion coefficient are, the faster the nuclide transport is.

The soft clay stratum is prepared to use vacuum preload method in a large-scale model test tank. Model tests of a bucket foundation in the stratum are conducted to research its bearing capacity under different vertical static and horizontal cyclic loads. Research results show that the bearing capacity of the foundation under horizontal cyclic loads is less than that of under horizontal static load. The cyclic load and cycle-index which lead to foundation failure depend on vertical static load. The larger the vertical load is; the less the failure of horizontal cyclic load corresponding to the number of cycles is. According to model test condition, the simulation calculations are performed by using the cyclic strength relationship of the stratum and elasto-plastic FEM. Calculating results are in good agreement with test results, which show that the horizontal cyclic bearing capacity of the bucket foundation in the soft clay can be evaluated by using elasto-plastic FEM based on the cyclic strength relationship.

The sliding zone made up of fault F42-9 and lamprophyre controls the stability of left cable-machine slope and arch dam abutment slope at Jinping First Stage Hydropower Station. The elastoplastic mechanism about reinforcement slope during excavation is simulated based on the occurred texture planes parallel to fault F42-9. The analytical results show that the designed reinforcement scheme can not ensure slope stability because of the sharply decreasing with rock mass behavior when the texture planes parallel to fault F42-9 are concerned. For sake of slope stability, it is proposed to design stronger reinforcement measures timely based on the exposing geological data during cable-machine slope and arch dam abutment slope excavation.

Based on rock with different scales on one site, scale effects on its fracture mechanism are studied in three scales of microscopic, mesoscopic and macroscopic states by rent edge tracking by triaxial rock material test system, crack line in cut plane or abrasive plane of rock specimens and breakage line of rock mass on site respectively. Method of coupling circle and square to calculate the fractal dimension is forward, whose superiorities are discussed and used to study fractal feature of rock fracture. There is a non-scale zone of 0.002—4 000 mm for studying fracture mechanism of rock in microscopic, mesoscopic and macroscopic scales. In the non-scale zone, self-similarity of distributing law of fracture structures is outer reflection of inner fracture mechanism of rock in every state. The results provide a possible method to study failure mechanism of jointed and fractured rock beyond scale limit.

Taking Xiamen Subsea Tunnel engineering for example, the relation of disintegration content and time is analyzed through the laboratory test; the disintegration of similar soil surrounding rock in water and the influence of uniformity and density degree of soil samples on disintegration are discussed. The reason of unstability of tunnel face is analyzed from water-soil interaction. The research results show that disintegration of soil samples is related to granulation percentage and density degree; disintegration curve of uniform and compact soil samples has three phrases. Disintegration of non-uniform and incompact soil basically accomplishes in seventeen minutes; but non-uniform and compact soil samples need more minutes. Disintegration adds up to 100 percent as time flies. Drainage and duly shoring are necessary in construction process because the stability and self strength of surrounding rock will reduce due to intenerating from water and disintegrating.

According to the deformation compatibility method and nonlinear optimization method, and using Fmincon function from the optimization box of Matlab, optimization design model of cable-anchored piles is established regarding the project cost as its objective function , the primary design parameter is optimized at the least cost of cable-anchored piles. The application of practical engineering shows that: the direct investment can be reduced to a certain degree in comparison with the original project by the optimization design and it brings great economic benefit.

Application of the combined pile composite foundation to coastal soft soil areas is described. Based on in-situ stress measurements and three-dimensional numerical computation by FLAC3D, the stress development in piles and nearby soils is analyzed. Meanwhile, the mechanism of pile-soil interaction and the bearing ratios in piles and soils are analyzed in detail. The results show that the combined pile composite foundation can develop the properties of two kinds rigidity reinforced pile. It has obvious economical and technical benefit and good applicable results.

A new method is presented to capture the stress and the displacement fields of a slope in centrifuge model test process based on the scheme with the combination of physical measurement and numerical analysis. The displacement field is measured by using non-contact displacement measuring system on the basis of image analysis in centrifuge model test. Consequently, the stress field is obtained by using numerical simulation with back analysis. Such a method has been used for several centrifuge model tests. It has been confirmed to obtain the stress and the displacement fields of a slope in centrifuge model test process reasonably. The test results show that the progressive failure of a slope is dependent significantly on the process of the strain localization and stress concentration.

Aiming at the problem of pillarless sublevel caving structural parameters of the third period mining area of Jinshandian Ore Mine, the possible structural parameters are simulated and analyzed by using sublevel caving simulation system –SLS which is developed by Northeastern University of China and the geotechnical engineer software-FLAC3D which is developed by ITASCA Inc. The numerical experiment indicates that independent advance of ore breaking influences the recovery index evidently, and the independent advance of ore breaking of 3.5－4.5 m has more advantage in recovery index. Also considering the rock blasting effect, the independent advance of ore breaking of 3.5 m is recommended. The numerical simulation of sequential excavation of tunnel groups in a mine block is also carried out. By analyzing the displacements, stresses and plastic zone of excavation simulation, it is concluded that the tunnel groups have satisfactory stability with the designed structural parameters. To sum up, sublevel height of 14 m, drift interval of 16 m, tunnel width of 3.6 m and tunnel height of 3.2 m are reasonable for both the recovery index and the surrounding rock stability.

A multi-node finite element method for numerical simulation of unconfined seepage flow through porous media is presented. Using multi-node elements to approximate the free surface of seepage, the shape functions of multi-node elements are constructed by mean value interpolation. The quadrilateral/triangle elements are used to partition the remainder domain far from the free surface. Giving an initial location of free surface and solving governing equation of unconfined seepage flow problem by multi-node finite element method, according to water head value of nodes on free surface to adjust the location of nodes, the final location of free surface is obtained by iteration technique. Numerical analysis of seepage problem of earth dam shows validity and accuracy of the method.

The experiments of soil-water characteristics curves are made under different consolidation pressures for sliding zone soils of Gushubao landslide in the Qingjiang valley, with an advanced unsaturated soil shear instruments which can control suction. The experiments show clearly the influences of consolidation pressure on the soil-water characteristics curves. The varied consistent functions have been established from the experiment data of soil-water characteristics curves; and the physical meanings of parameters in the consistent functions have been deduced and discussed. Finally, a comprehensive function expression which can reflect the relation among consolidation pressure, suction and water content, is established. The study has made up for the deficiency of other methods which can not consider the consolidated pressure and is very significant for the supplement and development of the theory and experimental method of soil-water characteristics curves.

Bifurcation tunnel is one of the new types tunnels. Taking the project of Qishucao bifurcation as the background, the field experiments of vibration effects of rock masses in tunneling blasting have been done. Based on the measurement of waveforms of the vibration velocity in different distances away from the tunneling blasting sources in the working face of adjacent tunnel, blasting vibration analysis of concrete lining tunnel is described by analyzing the peak particle velocity and its main frequency, especially for the blasting dynamic characteristics of mid-board and its vibration velocity variation. The results of the tests and analysis show that: (1) the near-blast side of old tunnel is the strongest vibration zone and the radial vibration is the highest which has a regular varying character along the mid-board; (2) the seismic effect of cutting hole blasting is the most intensive and its intensity is about two times greater than that of the other two blast-holes blasting; (3) the main vibration frequency of concrete lining is mostly low frequency from 20 Hz to 95 Hz, the higher frequency is absorbed quickly. (4) the peak vibration velocity always appears at the vault or in the middle of the mid-board in the same testing cross-section of the old tunnel; the Sadoy ’s formula is not reasonable for the vibration prediction of particle vibration near the blasting face. In light of construction characteristics of the adjacent blasting, the control measures of blasting vibration are proposed; the presented research achievements have better applied to practical project; and satisfactory results are obtained.

It is an important method for studying the rheological characteristics of rock to choose an appropriate rheological model and obtain the corresponding parameters based on the triaxial creep experiment of rock in lab. However, there are always a few abnormal values in sample data due to the influence of experiment conditions and random noises; the estimation accuracy may be worse if we use the ordinary least square algorithm to estimate parameters. The robust estimation theory derived from statistics is applied to the parameter identification by using double quadratic iteratively weighted least square algorithm; and it can reduce estimation bias due to the presence of abnormal values. This method is compared with that using ordinary least square estimation; the result shows that the former has high accuracy, uniform convergence and strong robustness, which is better than the ordinary least squares estimation.

Based on the strength reduction method in slope stability analysis, two-dimensional analysis is promoted to three-dimensional slope analysis; and its definition way of safety factor, yield rule and destruction criterion are researched. The three-dimensional finite element analysis conform to the reality more than traditional three-dimensional limit equilibrium method and two-dimensional finite element analysis, and it may simulate the solution of practical project well by example. Also, some influential factors in two-dimensional and three dimensional analyses are discussed; and some conclusions are drawn as follows: the computed result by using Mohr inscribed circle yield rule is less than that by using Mohr circumcircle yield rule in the same model. The lateral boundary constraint condition and the ratio of length to height have well influence on the computed result; the safety factor will increase greatly when lateral is restrained completely, but reduce gradually along with the increase of ratio of length to height.

Up to now, dewatering applies more and more in kinds of works; and a set of design and construct methods form. However, few people study the analysis of the dewatering effect. Large scale numerical model research carries out for the dewatering drainage engineering in a certain open coal mine excavation. Based on the hydrogeological condition, a reasonable numerical model builds up by using Modflow, and it is analyzed the detail dewatering effect under different conditions. Actual calculation results show that the dewatering effect influences greatly by factors such as the time of wells added, the single well pumpage, the amount and array of the wells, and the interaction among the wells, etc. Batch & time-sharing, wells array optimizing and single well pumpage adjusting are the most important influence factors of the optimized design and the design measure to enhance the water lowering effect. The action rule of these factors will provide some essential bases for the dewatering design and construction and actual engineering effect.

Mechanical properties of Coal Seam No.13 in Jianxin Colliery are tested by using Rock Servo Mechanics Test System. The coal masses unaxial compressive strength is tested to be 6.928 MPa through size effect study. And the coal is testified to accord with Mohr-Coulomb elastoplastic model by triaxial compression test. Based on the experimental study, the pillar stress and maximum subsidence are studied by using FLAC3D; and the pillar security is analyzed after selecting the mining strip width of 25 m, then the stability of coal pillar is studied. The results indicate that the width of 20 m can maintain pillar stability. On the basis of coal test in laboratory with numerical simulation method, studying strip pillars’ stability of different widths can insure its stability and safety while reducing the size of pillar, then avoiding blindness by using empirical formula merely.

Based on the logarithmic spiral failure surface and combined with the upper bound theorem of soil plasticity mechanics, a technique of slice for analyzing translational failure mechanism of the stability problem of strip foundations subjected to uplift loads was proposed. According to the term that the rate of work done by external loads and soil weight is equal to the rate of energy dissipation in the kinematically admissible velocity field, the virtual work rate equation was deduced, through which the vertical uplift capacity can be calculated. Bearing capacity factors have been determined which showed that the part of uplift capacity corresponds to cohesion is affected by respond coefficient m and the other two parts which correspond to surcharge and weight separately, can hardly be affected by it. Through the comparision of results which obtained by predecessor's experimental materials and Meyerhof and Adams’s computation theory, the correction and feasibility of the suggested method is indicated, and the conclusion that m only affects cohesion term Fc remarkably is validated by the results in sand and cohesive soils.

Up till now, the theories of reinforced cushion cannot meet the needs of practice, the designing method of reinforced lime-soil cushion attracts most researchers’ attention. According to the ground treatment of the deep collapsible loess in the Zhengzhou-Xi’an Passenger Dedicated Railway Engineering, the limit state theory model of the reinforced lime-soil cushion above pile is established; the loading feature is analyzed; and the design method is presented. Considering pile diameter, pile space, subgrade height and geogrid strength, the parameters such as the cushion thickness etc., are analyzed. It is suggested that the double layer structure and the double direction reinforced geogrid with small elongation rate should be used first to reinforced lime-soil cushion in the Passenger Dedicated Railway.

By using FEM, the critical height of soil-nailing foundation pit is studied; and the influential factors of critical height of soil-nailing foundation pit is analyzed too. The studying results indicate that the soil-nailing foundation pit has a critical height, the critical height of soil-nailing foundation pit is related to the ultimate bearing capacity of foundation; so through the solving thought of ultimate bearing capacity of foundation can get the result of the critical height of soil-nailing foundation pit; studying the influences and laws between the critical height and the chief parameters of soil-nailing foundation pit, comparing the result with the theoretical result from upper and lower solutions of soil plastic mechanics under the condition of homogeneous soil. The case studies verify that this method can fit each other well. A new idea for determining critical height of soil-nailing foundation pit is provided.

Aimed at dynamic problem of wave-induced response in silty seabed, and combined with the results of model test in wave flume, numerical analysis method based on wave action is carried out to calculate the increment of excess pore water pressure. Numerical results indicate that the method is in good agreement with those obtained from laboratory test. It can be used to clarify the developmental mechanism of pore pressure in silty seabed, and to evaluate the liquefaction potential of the seabed.

Based on Coulomb’s earth pressure theory, assuming the trace of the principal stress arching in the back of rigid retaining wall as parabola, the theory formulae are obtained including the lateral coefficients of active and passive earth pressures and the friction coefficients of horizontal differential elements; then improved formulae of active and passive earth pressures are presented. The results show that the calculation results considering soil arching are consistent with the ones of model tests. Being in active limit state, the inner friction angles become smaller, the outer friction angles on the soil-wall interface become larger; the effect of soil arching becomes more distinct; as a result, the application point of resultant active earth pressure is higher. Being in passive limit state, the inner friction angles and the outer friction angles on the soil-wall interface are larger, the effect of soil arching becomes more distinct; and the application point of resultant passive pressures is lower.

The coupled hydro-mechanical processes in fractured rock during tunnel excavation are analyzed, using the stochastic continuum model that represents the spacial variability in hydraulic properties of fractured rock mass. The stochastic permeability fields are generated with the sequential indicator simulation, which is a non-parametric geostatistical technique and allows the input of the permeability probability distribution of arbitrary shape. The resulted permeability fields are then mapped onto the 3D finite element grids for the coupled hydro-mechanical analysis. A joint material model that can represents the weaken planes with specific orientations is used for the mechanical calculation in the study. The results show that the stochastic continuum model can predict the inflow rate into the tunnel; and the natural, spacial variability in hydraulic properties plays an important role in the coupled hydro-mechanical processes of the fractured rock mass. It is also found that the pore pressure will rise quickly before the water has a chance to move and equilibrate at the beginning of every excavation stage. This transient coupled hydro-mechanical effect may cause local failures in rock.

An in-situ static vertical loading test of rectangular diaphragm wall in loess subgrade, for which a self-balanced method was employed, was performed firstly at home and abroad. According to the testing results and based on the physico-mechanical properties of loess, load transfer characteristics of the rectangular diaphragm wall in loess subgrade were analysed in detail. The results indicated: bearing characteristics of rectangular diaphragm wall in loess subgrade behaved the properties of end support friction piles; bearing capacity of rectangular diaphragm wall in loess subgrade consisted of lateral frictional resistance and end resistance; development of lateral frictional resistance and end resistance of diaphragm wall were related to the factors, such as the relative displacement of the diaphragm wall and loess, the physico-mechanical properties of loess and so on; the load sharing ratio of end resistance of diaphragm wall was 40.3 percent while reaching the ultimate load; the lateral resistance of diaphragm wall was increasing gradually with the augment of the relative displacement of diaphragm wall - loess, but with different increment in loess layers; the maximum axial force of diaphragm wall located the position of loading, with the development of the lateral resistance of diaphragm wall in loess layers, the axial force was decreaing while the distance of the load box is increasing.

The hetergeneity of soil is a common phenomenon in geotechnical engineering. In view of the characteristic of the soil stability during excavation in soft clay, an upper-bound limit analysis method is used to solve the problem of basal stability in heterogeneous soft soil. The applicability of the upper-bound method is discussed to ensure that it obeys the requirements of the limit analysis theorems. Prandtl mode of the bearing capacity of foundation is then adopted to construct a kinematically admissible velocity field for the upper-bound method. Based on the kinematically admissible velocity field, the calculation formulas for the basal stability in heterogeneous soft soil are established. With the proposed formulas, the effect of the soil strength, the width of foundation pit, the depth of retaining wall and the location of the hard stratum on the stability coefficient are discussed. The basal stability of several cases is studied and the calculated safety factors are compared with those obtained by other methods. The comparison demonstrates the applicability of the upper-bound method used in this paper.

In order to solve the problem of reckoning without shear contraction in K-G model suggested by Specification of Soil Test and keep its simplicity, a shear contraction modulus is proposed and a three-modulus modified K-G-D model is suggested which has seven parameters; the integrated incremental stress-strain relations are expressed by mean normal stress, generalized shear stress, volumetric strain and generalized shear strain are given. Model calibration for normal consolidated clay soil is carried out by isotropic consolidation tests and drained triaxial compression tests that the mean normal stress remains constant, model verification is carried out by the drained conventional triaxial compression tests, the computation results by the model parameters coincide well with curves of the tests, which demonstrates that the modified method is rational and applicable. The modified model is capable of reflecting the characteristics of pressure sensitivity, shear contraction and strain hardening, and suitable to underconsolidated and normally consolidated clay soils, loose and medium sands under the stress paths of mean normal stress increasing or remaining constant. In addition, the model calibration does not need additional tests, the modified model is clear in concept, simple in form and convenient to use.

Based on a series of dynamic triaxial tests in which the frequency is equals to 0.02 Hz, 0.1 Hz, 1.0 Hz, the effect of cyclic loading frequency on the lightweight clay mixed with EPS beads soil (LCES) is investigated. The results of dynamic triaxial tests show that the cyclic loading frequency has obvious effect on the LCES, with the decreasing cyclic loading frequency, axial strain and damping ratio increase, dynamic strength and dynamic modulus decrease when cyclic loading frequency equals to 0.02-1.0 Hz. Compared with high cyclic loading frequency, the pore water pressure at low cyclic loading frequency develops more quickly, and the effective confining pressure of LCES decreases quickly at the same time, which leads to the destruction of LCES, so the dynamic strain increases and the dynamic strength decreases accordingly.

Based on the capillary theory and Sierpinski space hypothesis, a fractal model for unsaturated seepage in fractured rock masses of function among capillary pressure, effective water saturation and relative permeability coefficient is established. In order to provide evidence to unsaturated seepage flow theory, the box dimension method is studied according to the technique of Monte-Carlo three-dimensional network simulation. The relationship between fractal dimension and unsaturated permeability is studied. A calculation example in Nuozhadu slope is given .The comparison results of proposed model and the Brook-Corey model indicate that the proposed model seems to be adequate to describe the fractured rocks for small ranges of fracture aperture and the relative permeability is mainly influenced by the maximum fracture aperture.

Rock mass quality has great influence on rock slope stability. So it is very important and necessary to re-classify the rock mass and evaluate its quality correctly after excavation. Based on the unloading rock mass mechanics theory, the arch dam abutment excavated high slope of one power station is analyzed by finite element method. Comparing initial stress field with excavation stress field, the rock mass unloading degree is studied; and then the degree of rock mass quality deterioration after excavation is also gained. With the progress of excavation, areas and degree of unloading change constantly. In order to simulate the influence of dynamic unloading, the rock mass mechanical parameters are adjusted continually according to the changing areas and degree of unloading after every excavation step. And considering the effects of excavation and unloading, the rock mass quality is re-evaluated with RMR method according to the rock mass mechanical parameters after excavation. The results show that the RMR value of slope rock decreases linearly with the increase of unloading degree. On the basis of the relationship between RMR value and unloading degree, considering unloading as an important influential factor, the evaluating parameters of the RMR method are revised, which has referential value for rock mass quality evaluation after excavation.

The lithology of the entrance segment is weathered metasandstone, existing shallow and unsymmetrical pressure, constructing with three-pilot drift method. The construction process of Fuxi shallow multi-arch tunnel under unsymmetrical pressure using special-purpose analysis program of fast Lagrangian analysis of continua in 3-dimension is analyzed. Comparing excavated shallow-buried tunnel with excavated deep-buried tunnel, the changes of tunnel deformation, and stresses and displacements of middle-wall and supporting structure in different construction stages are obtained. By comparison actual tunnel construction orders are optimized. Comparing to monitored and measured data in site, the analysis results provide a scientific basis and technical guidance for construction of Fuxi shallow multi-arch tunnel under unsymmetrical pressure.

The spatial effect of earth pressure is considered; and the deformation compatibility of space that the cap beam applies to the double-row piles support structure is analyzed. Besides, the affection on the earth pressure of both the front and the back row piles due to sliding plane and array pitch is considered too. Based on the beam on elastic foundation method, a new calculation model for a double-row piles retaining structure is proposed. Comparing the calculation results of the theoretical model with the actual observation data, it is shown that the effective calculation result can be obtained by reasonable parameters applied to the model.

The altered rock is the soft rock which is scarce in the engineering. For a major engineering project in Southwest China, the altered rock is located in the key position of the project. In order to guarantee the project for long-term stability, the mechanical property of the altered rock should be deeply and fully studied. On the basis of systematic conventional triaxial compression test for the saturated altered rock under different porosities, the test results are analyzed and summarized. It has been put forward that there are three types of stress-strain curve before rock destruction and three types of stress-strain curves after rock destruction. The conclusions have been proposed that the altered rock destruction is effected by both confining pressure and porosity. When the confining pressure is 12 MPa, the brittle failure is dominating. Only when the porosity is more than 16 % and the confining pressure is more than 4 MPa, the brittle-ductile fracture diversion state is possibly found. Furthermore, the confining pressure of brittle-ductile fracture state diversion decreases along with the porosity increases; and the critical state stress ratio increases along with the porosity increases.

Support vector machine (SVM) is a novel and powerful learning method which is derived based on statistical learning theory (SLT) and the structural risk minimization principle. Traditional SVM only deals with the binary classification problems, however, there are large numbers of multi-classification problems in practical engineering. With a view to the main factors with important influence on sand liquefaction, multi-class support vector machines model based on clustering-binary tree is established. The nonlinear relationship between sand liquefaction and influencing factors is obtained from the finite empirical data by SVM. The results indicate that the structure of model base on SVM is reasonable; this algorithm is feasible; and it can predict the sand liquefaction more accurately．

A new construction technique of dynamic compaction for the conventional compacted rock filling embankment is discussed by analyzing the settlement causes of high rock filling construction practice in Luoyang-Sanmenxia Expressway; it is important to ensuring construction quality of high rock filling embandment in sloping area of expressways.

The influential radius is a controversial conception. For different aquifer conditions and concept models, there are distinct methods to calculate the influential radius. The empirical formulas, which lack of strict theoretical basis, are more popular in practice. The routine method to ascertain the influential radius in leaky confined aquifer is stretching the s-log(r) line through three or more observation holes in steady flow to find the zero-drawdown distance. The method may bring misunderstanding to engineers; the misreading has been pointed out and the routine method has been revised.

The design of the high slope k35 of expressway which links Guangdong and Jiangxi provinces selected the strength parameter of thoroughly met sandstone, and the values of safety coefficient F is worked out by Janbu and M-P methods were all more than 1.20, which indicated that the slope was in a stable condition. But the result of monitoring which didn’t confirm to the design indicated that this slope deformation increased sharply and the slope was in an unstable deformation condition after the strong rainfall. Therefore, on the basis of data of the monitoring, selected a new calculation parameter and made a checking calculation on the stability of slope. The result of the safety coefficient was Fs = 1.05, which showed the slope was in an unstable condition. According to the checking computations, the slope should be strengthened and consolidated; and the safety coefficient Fs should be checked after strengthening the slope. The result approved the effectiveness of the strengthening. After that, the deformation of the slope came down fast and it recovered a normal condition.

Calcareous sands generally consist of marine sediments. Compared to the terrigenous sands, they tend to crush easily under load, and the mechanical character will change subsequently. Laboratory triaxial shear tests under different confining pressures and strains on calcareous sands which are taken from the South China Sea are presented. And the particle size of the sample is sieved before and after tests. The results show that the particle breakage of sand is very serious under triaxial shear. And the crushability of the sand is quantified by using Hardin model. The relationship among confining pressures, shear strain and particle breakage is also discussed.

Starting with expatiating the heat transfer process of porous medium, heat transfer process between optical fiber and porous medium on non-seepage condition and seepage condition is analyzed one by one. The process of convection heat transfer between optical fiber and seepage is studied detailedly. The formulas of calculating heat transfer coefficient between optical fiber and seepage in the porous medium are deduced. Based on some hypotheses, the theoretical equation of seepage monitoring about thermal conductivity (seepage velocity), heating power, and temperature rise are deduced, which offers the steady theoretical foundation for the application of this technology.

With the widespread use of the waterproof and drainage technique of tunnel based on controlling drainage, some technical problems about tunnel lining design under external water pressure had been extruded more. According to construction examples of Longtan tunnel and Baiyun tunnel, optimization countermeasures about tunnel lining structure were studied against external water pressure by numerical simulation based on the mechanical response analysis of the lining under external water pressure. The study results showed there were increase stresses and internal forces on the side wall, the corner of the invert arch of the tunnel lining and the safety degree reduced more under external water pressure; a new concept of rise span ratio of the half below the tunnel lining was introduced from technical and economical aspects, whose addition was the chief countermeasure to optimize the structure of lining against external water pressure; the optimization countermeasures of the lining against external water pressure were put forward, which included in turn increasing the radius of the corner on the invert arch, decreasing the radius on the invert arch, thickening the arch on the invert arch and the arch of all lining, or these countermeasures could be used assembled sometimes.

Through the vertical static load model experiment of concrete single pile in silt, the change rule of the resistance of pile side and pile tip, the subsidence situation of different soil strata, and the changes of “neutral point” position and dragload of end-bearing pile and friction end-bearing pile are analyzed under the variety of the water content change of the soil around the pile. It is found that the “neutral point” position of friction end-bearing pile changes while the variety of water content and load grade of soil around the pile change; “neutral point” position reaches the tiptop near optimum moisture content and becomes higher along with the load increase.

It is difficult to build geological models for numerical simulation when meeting complex geological structures. In order to address this problem, a seamless modelling method for rock-mass structure is proposed and realized. A method for optimizing tetrahedral mesh generation based on the seamless geological model is also realized by developing direct method. Combining these two methods, a numerical model, which is coincident with geological realities and having optimizing mesh, can be built for numerical simulation. By using this method, a 3D geological model and its optimizing tetrahedral mesh are built for rock-mass on the bank of one dam.

The influence of lateral deformation of deep marine soft soil underlying embankment on its settlement through the triaxial and plane strain creep tests is studied. The result indicates that the relationship between the initial stress and strain is nonlinear, the shear stress produces unrecoverable lateral deformation which is an important component of the settlement. The lateral deformation expands all the time under undrained condition, while it not only expands but also shrinks under drained condition. There are corresponding relationships between shear stress level and the process of lateral deformation, when the shear stress level is low, the influence of lateral deformation on the settlement of roadbed is not so distinct, when it is high, the influence should not be neglected and it appears along the whole course of settlement.

The design principle and construction method from the case of Gome Shoppingcity excavation project on two-step composite soil nailing combined with spline-pipe soil nail, general soil nail and prestressed anchor are presented. A field investigation, including tensile forces of soil nail, excavation displacements and anchor stresses, and comprehensive analyses of the results are addressed. The characteristics of two-step composite soil nailing of excavation in sand and gravel layer are further investigated. Owning to the backslide effects, the mechanisms of soil nailing are changed. It also suggests that the horizontal deformation of excavation is controlled well by prestressed anchor of composite soil nailing support system. And the prestress loss of anchor after locking is obvious because of some factors, such as the limit of surface stiffness of soil-nailing wall and the small thickness of bearing plate. The curve which is formed by positions of maximum tensile forces of soil nails may be the most dangerous sliding curve.

Exact solution of multilayer elastic plane in a rectangular coordinate system is obtained on the basis of Fourier integral transformation and stiffness matrix method. Stiffness matrix for monolayer derived firstly based on the fundamental elasticity equations and some mathematic methods such as Fourier integral transformation. And then the stiffness matrix is established for multilayer elastic plane, using the finite element concepts in which layers are completely contacted. Therefore, exact solution of multilayer elastic plane is obtained from the solution of algebra equation formed by stiffness matrix and inverse Fourier integral transformation. Due to the element of matrix is not included positive exponential function, the calculation is not overflowed. The shortages of transfer matrix method are overcome. This method is clear in concept, and the corresponding formulas are given not only simple but also convenient for application. More important thing is the method can be used to solve other problems for multilayered elastic plane, such as thermo field and dynamics. A numerical example is presented to prove the correction of calculated results.

Some polymer materials with negative Poisson’s ratio had been developed, but negative Poisson’s ratio effect was seldom observed for rockmass. Based on the first underconstruction undersea tunnel as engineering background, a brief introduction of indoor test on the rockmass specimens was given; and negative Poisson’s ratio effect was observed during test. A new microcosmic deformation mechanism—lattic-rotation model which could interpret the observed test phenomenon was proposed; and a credible data proceeding method to obtain the actual value of Poisson’s ratio was proposed too.

Based on the continuity conditions at the interface on both sides, of which the pressures and velocities must be equal，the initial shock wave parameters of the medium surrounding a charge are given by calculating the equations valid for reflected wave in detonation products and the equations valid for shock wave in medium. Attenuation equation of stress waves, which is attenuated with increased distance of wave front from the vibration source, is extended from spherical charges to cylindrical charges based on the propagation theory of wave. Then the shock-wave parameters of the rock having the same distance from the detonation source are worked out in the case of decoupled charges and coupled charges. The conclusions obtained as follows: (1) the shock wave pressure is ten or hundred times larger than ultimate compressive strength of rock, then the smesh zone comes into being in the rock surrounding a charge；(2) in contrast with coupled charge blasting, decoupled charge blasting could decrease the initial shock wave pressure of bore wall’s rock, but increase the shockwave pressure of bore wall’s back rock. If the reasonable coefficient of decouple charge is adopted, the smesh zone will disappear and the dissipation of energy will decrease；(3) in view of a kind of nonlinear elastic medium, water, between detonation products and rock, can be suggested as an elastic buffer which increases the propagation of energy，protracts action time of shock wave and enlarges the action region of shock wave.

Gradient-dependent generalized plasticity mechanics (GGPM) in which the yield functions not only depend on stress tensor and an invariant plastic strain measure, but also depend on spatial derivatives of the latter quantity, is based on the generalized plasticity mechanics(GPM). It can describe the strain localization characteristics and the basic mechanical characteristics of geomaterials at the same time. In order to derive the equilibrium equations and the boundary conditions, an incremental functional in which the displacement , plastic multiplier and are independent variables, is constructed to build up the variational principle of GGPM. The stress boundary conditions as well as the plastic factor boundary conditions are obtained by natural boundary conditions, so a numerical model can be ensured for geomaterial strain localization.

k2SiO3 developed by Conservation Institute of Dunhuang Academy, is used for the protection of the earthen architecture sites under arid weathering condition, of which protective effect is good. The SEM tests of artificial remoulded clay sampled from ruin region without k2SiO3 material, with 5 % concentration saturating and natural air drying once or three times are designed to study the change of clay porous feature affected by k2SiO3 material. Based on images of SEM test, the pore structure of clay changed by the material is studied by means of statistical method of sub-area and computer image processing technology. It is found that the connection between clay particles consolidated by k2SiO3 has been apparently enhanced. Moreover, the stability of the soil becomes more stable. Finally, quantitative change of clay pore affected by k2SiO3 is studied by fractal dimension of Sandbox method. It is found that the fractal dimension of soil sample disposed by 5 % density of k2SiO3 material saturating and natural air drying three times, whose reinforcement effect is the best, is the minimum; and that fractal dimension of soil is not affected by segmentation threshold of gray value and amplification coefficient of SEM test.

Base on the analysis of the process of retrogressive landslide, it shows that the characteristics of retrogressive landslide are developed from underside to upside; and its scope becomes larger and larger. The treatment to retrogressive landslide is passive and active reinforcements, but some problems will be brought in by passive reinforcement, such as the decline of shear strength of sliding surface, the expanse of sliding range, the increase of passive reinforcement force, the loss of project budget and the destruction of environmental resources. The inherent strength of potential sliding surface can be utilized by active reinforcement; and then the project budge will be decreased. When passive reinforcement is used in project, the developing process of retrogressive landslide should be considered, the initial sliding mass must be reinforced effectively, the retrogressive mass afterwards should be treated by principle of compensatory reinforcement.

With triaxial apparatus specially made for unsaturated soil, the tests of shear strength and soil-water characteristic curve of unsaturated loess under different water contents are performed. The test data show that the shear strength of unsaturated is bigger than that of saturated loess; and it decreases with increasing water contents and lessening matric suction, and vice versa. The shear strength of unsaturated loess will be close to that of saturated loess when water content is saturated. The internal friction angle changes little while water contents change, but the total cohesions change greatly under different water contents. The loess has smaller matric suction and total cohesions at high water contents. According to the results, the model of shear strength of unsaturated loess is proposed. The parameters can be derived easily. The error is small, and the model meets the requirement of calculation of sheer strength of unsaturated loess.

As underground resources exploitation goes deeper and deeper, large deformation and failure of soft rock mass surrounding deep soft rock roadways, together with reasonable reinforcement techniques are main factors impacting safe and sustainable mining. Combined with results of indoor mechanical test on weak structural planes and soft rocks, damage criterion and damage evolution model of weak intercalated layers are established and applied to stability analysis of one deep soft rock roadway excavation of Huainan coalmine. Deformation characteristics, plastic zone of wall rock and failure zone of weak intercalated layers are studied; and reasonable reinforcement scheme is proposed. The achievements from the research can provide references to the design of supporting scheme of deep soft rock roadway.

Rock is a kind of physical nonlinear complicated medium, under deep-buried condition the deformation of surrounding rock system shows geometrical nonlinear; and the interaction between two nonlinear mechanisms makes the unloading of surrounding rock system evolved complexly. Based on Fast Lagrangian Analysis of Continua 3 Dimensions, shear-tension failure model of Mohr-Coulomb is established. Numerical simulation of deep-buried tunnel surrounding rock system is introduced by using large deformation method; and chaotic dynamic theory is drawn into. From the results of numerical simulation, Lyapunov exponent has been extracted from evolution data in the unloading process of surrounding rock system. The analysis indicates that the typical chaos character has been demonstrated in the process of unloading for deep-buried tunnel surrounding system; and the evolution of surrounding rock system is sensitive to the initial condition.

In the tunnel lining structure internal force calculation, it is indeterminacy for mechanics parameters of surrounding rock and parameters of structure. At the same time, the indeterminacy has the boundary, which can be estimated by a reasonable interval numbers in engineering. Changing a single random variable in the interval numbers, the structural internal force can be solved by adopting a finite element equation. But in the case of multi-variable, considering indeterminacy of calculation model and complexity of mathematical solution, the finite element procedure can be used to educe the action effect of each variable to structure’s internal force, then the interval values consist of different parameters are obtained; and the interval values of tunnel lining structural inner force are confirmed finally. The method can provide a new method for the calculation of interval numbers of tunnel lining and engineering application.

Model test method is used to analyze the distributing characteristics of stress and settlement with different grain gradations, series, water contents and vertical quasi static loads in soft rock roadbed. It is concluded that roadbed stuffed by soft rock with definite grain gradation and water content can satisfy technical requirement of roadbed design criterion. High load test is used to analyze deformation and destroy characteristics of soft rock roadbed with two kinds of grain gradations and water contents. The results show that using the method of the soft rock roadbed can make full use of soft rock resources along the railway line, occupy less cropland, protect environment and make considerable social and economic benefits.