With a linear Mohr-Coulomb failure criterion, an estimate of bearing capacity of a strip footing resting on a homogeneous and isotropic geomaterial foundation had been made using the methods of limit equilibrium, characteristics line and limit analysis in the previous literature. However, experimental data have shown that the strength envelopes of almost all geomaterials have the nature of nonlinearity. In this paper, a nonlinear failure criterion is employed to evaluate the bearing capacity of a strip footing using the upper bound theorem of limit analysis. A generalized tangential technique is presented to formulate the problem of bearing capacity as nonlinear programming problem. The optimum solution is obtained by a nonlinear sequential quadratic programming algorithm. From the numerical results, it can be seen that the nonlinear failure parameter has a significant effect on the bearing capacity; and that the solutions presented in this paper agree well with previous results if the nonlinear failure criterion is reduced to a linear Mohr-Coulomb failure criterion.

In-filled trench is equivalent to an obstacle in half-space when it was used for isolating vibration. Based on the integral equation of Rayleigh wave scattering, the paper studied the passive isolating vibration in far field by in-filled trench barrier in 3-D, and discussed some key factors affecting effectiveness of barriers. The results show that rigid material has a better effect than flexible one in isolating vibration, so the former should be selected as barrier material in engineering. The effect of isolating vibration is due to the depth and thickness of the trench. When the depth of barriers is more than a Rayleigh wave length, the effectiveness of isolating vibration increases for a little with the barrier depth increase.

Considering engineering practice, the viscoelastic two-phase model of soils is adopted to analyze the transient dynamic response of the spherical cavity in nearly saturated viscoelastic soils. The analytic solution in transformed domain is got by the method of Laplace transformation; and numerical results are presented through inverse Laplace transformation. The displacement, stresses and pore water pressure are investigated during the response and compared with the elastic case; and some features of the problem are revealed. The study is reasonable for engineering practice and provides an effective method for analysing the similar problem about dynamic response of underground structure.

The soils under the foundation of building or within the slope are usually in complex initial stress state before subjected to cyclic loading induced by earthquake shaking or wave loading. The conventional laboratory experiments of soils cannot authentically reproduce dynamic behavior of soils under complex consolidation stress states. The soil static and dynamic universal triaxial and torsional shear apparatus recently developed in Dalian University of Technology is employed to perform experimental tests on Fujian standard sand with relative density of Dr=30 % under complex initial stress state subjected to cyclic torsional shear loading. Through a series of soil tests, the effects of both initial orientation of principal stress and the initial ratio of deviatoric stress on dynamic modulus and damping ratio of sand are investigated systematically.

The authors analyze the stress intensity factors at the tips of cracks in a tunnel lining and the safety factors for bearing capacity of the tunnel lining by using a 2D FEM code, in which the influences of lengths, widths and number of cracks are mainly considered. The computation results show that the stress intensity factors raise and the safety factors of bearing capacity decrease with the increase of lengths and number of cracks, but the effect of crack widths is not so obvious.

The deformation of surrounding rock mass has prominent rheological behavior while the tunnel was excavated. The deformation of surrounding rock mass was analyzed on the basis of Poyting-Thomoson model, and the characteristics of surrounding rock mass deformation under initial support were discussed according to the universal analytical viscoelasticity solution and the monitoring results of Shilong Tunnel of Yu(Chongqing)-Sha(Changsha) Expressway. Analogy surrounding rock mass under initial support or not with rock creep under uniaxial or triaxial stress. Initial support can diminish the permanent deformation value of surrounding rock in a certain extent, and reduce the deformation rate of tunnel surrounding rock greatly. These achievements are very helpful to the determining the time of secondary lining, and have instrutional significance and referential value for similar engineerings.

Hydraulic fracturing is one of important effect factors in water gushing out of deep-buried tunnel construction and cracking and seepage of high head tunnel .Its failure mechanism study is a hot topic in geotechnical engineering fields. Based on stress state in fracture surface and fracture mechanics, the fracture propagation is divided into tension-shear and compression-shear mixed cracking. Using fracture propagation engineering criterion, calculation formulae of critical internal water pressure of two kinds of failure model are obtained respectively; and its effect laws as fracture direction and lateral geo-stress coefficient are studied. The study shows that critical internal pressure of two kinds of model is not varied as fracture direction changing when the lateral pressure coefficient equals 1.0. Under tension-shear complex model, fracture is most easily fracturing when fracture direction is parallel with direction of principal stress. Under compression-shear mixed model ,distribution law of critical internal water pressure is same as tension-shear complex model when ( ) large than 1.0. But fracture is most easily fracturing when ( ) less than 1.0 and fracture direction are 45°or 135°angle with principal stress.

With the rapid development of new-type weapons, the demand for the efficiency of defense layer becomes higher and higher in current civil protective construction. The focus of this paper is primarily on the attenuating and screening stress-waves by using cavities embedded in defense layer. Based on a great many numerical calculations, it has been found that the weakening amplitude of stress-waves behind certain artificial cavity is clearly different if the size dimension and geometry shape of the cavities are changed. Besides, two approximately fitted formulae for the decay factors of peak σy, towards the circular and rectangular cavity are put forward, which can be used to estimate the value of decay factors (DF) at one specific place or the size dimension of cavities under certain conditions; and even can predict the minimum safe distance in order to reach expected attenuating effect. All those can be referenced for the design of intelligent defense layer in anti-explosion engineering.

Based on precise measurements of topography on artificial irregular rock joint by employing a laser scanning instrument, at first, the joint surface was visualized by using GIS technique. Then the distributions of the geometrical properties such as roughness, aperture and asperity height were analyzed according to the histogram and the characteristic number of frequency distribution. The results showed that the asperity height and the aperture of the rough surface in granite joint and sandstone joint approximate match the normal distribution; while the roughness slope of the rock joints approximate matches Γ- distribution. For different kinds of rock joints, the distribution of the geometrical properties is respectively similar to each other.

A series of experiments relating to bubble cloud and erosion mechanism of cavitating water jets were carried out for different nozzles with different pump pressures and ambient pressures. The objective of this work is to find the relation between the erosion and the bubble cloud, determine drilling parameters such as the feed speed or rotating speed for a water jet drilling system, and explore nozzle operating conditions and nozzle designs to reduce the input energy by reducing the pump pressure. Visualization studies of the bubble cloud show that the length and width of the bubble cloud of the convergent-divergent nozzle are larger than those of the convergent-straight nozzle. The erosion tests confirm that it is the bubble collapse that causes the erosion, and the standoff distance plus the drilling depth equals to the bubble cloud length. In drilling brittle hard rock, erosion happens in the first few seconds, and after that, erosion does not increase with time.

The loading behaviors of the rigid piles-composite foundation by reverse construction process before and after sealing piles are analyzed respectively; and equations to calculate the stress ratio and the depth of the neutrality point are deduced. Based on the analysis results, the stress ratio (or load sharing ratio) can be adjusted by controlling the settlement difference between piles and soils, the replacement ratio and length of piles. Deformation is the main factor in design of rigid piles-composite foundation. A practical example shows that the calculation results are satisfied compared with the testing results.

Based on the small scale model tests, the structural performances of ten reinforced and unreinforced slopes were studied , which include two slope angles, 1:1 and 1:1.2; two kinds of geogrids, Tensar 40RE and 80RE; and three different reinforcement layers, zero, one and three layers. Under a strip footing load near the slope crest, the deformations of slopes and geogrids were modeled. The coefficients of reinforcement how to affect the structural performance of embankment slopes were carried out; and the mechanical character of geogrids in soils was derived. It is shown that the geogrid will improve the stability and the capacity of the slope.

In engineering practice, the subsoil with vertical drains is often composed of multi-layer strata and the subsoil is partially penetrated by vertical drain wells. Based on the assumptions that the section with vertical drains satisfies equal strain condition and the section without vertical drains satisfies Terzaghi’s one dimensional consolidation theory, the existing simplified consolidation theory of ground with partially penetrated vertical drain wells is developed so that multi-layer subsoil can be take into account. The orthogonal relation of the system is obtained using the boundary conditions and continuity conditions in vertical direction. The consolidation solutions of the system is presented. The solution has comprehensive applicability. The existing consolidation solutions of simplified ground with partially penetrated vertical drain wells can be obtained by changing the number of the stratum of the section with vertical drain wells and the section without it. The solution has been coded into a program and a case is analyzed using it. Analysis shows that the average degree of consolidation of the system defined by pore pressure is different from that defined by settlement. It also shows that existence of crust can accelerate the consolidation of the stratum.

Based on the theory of lower bound limit analysis, finite element are used to discretize the mechanism. The statically admissible stress fields that are satisfied the conditions of equilibrium, stress boundary, yielding and stress discontinuity, are constructed. The pore water pressure is considered as an external force, similar to gravity. By using the idea of linear programming, lower bound limit analysis models of mathematical programming for slope stability are established; the model can evaluate the safety factors and stress field of lower bound. Finally, taking two classical soil slopes for examples of calculating slope stability, the comparisons among the results of various methods are made. The results indicate the correctness of the method and the program.

The method of backfilling expansive soil, lime soil and geonets in staggered layers used in the disposal of weak expansive soil embankment is introduced. By the in-situ tests, the bearing capacity and rebound modulus of soil basement in different layering combinations are obtained and the differences among different combinations are analyzed and discussed. The results show that the structure of weak expansive soil plus lime soil; and the compound structural type of weak expansive soil, lime soil and geonets wrapped in the soil embankment are scientific and reasonable in the disposal of expansive soil embankment. With this structural type, not only the expansive soil along the road but also their strength can be fully utilized only when the requirements of design are satisfied by the construction quality of each structural layer.

Sorption of Zn2+ from aqueous solutions by fly ash, clay and bentonite was investigated. The results of kinetic experiments showed that the sorption process of Zn2+ was rapid. The sorption data showed that sorption capacity of Zn2+ by fly ash and bentonite was much larger than those by clay and silty clay; and the sorption capacity of Zn2+ by fly ash was equal to that by bentonite. Equilibrium modeling of sorption showed that at high concentration，the sorption of Zn2+ by fly ash, clay and silty clay were fitted to a Langmuir isotherm. The results also showed that when Zn2+ loading in adsorbents increased，the percentage of Zn2+ sorption by adsorbents such as fly ash decreased.

Vertical and annular reinforcing steel bar stress and pipe-soil contact pressure during pipe jacking were monitored on the spot. Field data were analyzed. It showed that axis force increased along with pipe jacking at the very start, and it maintained stated basically when jacking to a certain distance. When inner side reinforcing steel bar of tip and bottom pipe were pulled, outer side were pressed. And both sides of pipe were just contrary. Reinforced concrete pipe could be regarded as flexible pipe. Annular reinforcing steel bar bears very little but with great alteration. Pipe-soil contact pressure increased slowly along with pipe jacking, and it also maintained stated basically after some distance. Contact pressure of tip pipe was greatly affected by grouting. The pressure decreased obviously after grouting and it could be adopted as up-earth gravity. Contact pressures of both sides were affected less. Compared with the tip pipe, they were almost the same before grouting and noticeably bigger after grouting.

The geological characteristics of rock mass are main factors of affecting overbreak-underbreak of tunnels. It is important to analyze and forecast overbreak-underbreak of tunnels for evaluating rock mass quality correctly and classifying the rock mass and researching the relation between rock mass quality and overbreak-underbreak. The relations among the classification of RMR and Q and overbreak-underbreak are researched. The relations among different tunnel radii and overbreak-underbreak in the same class rock mass are studied. According to these, the relation between the classification RMR and Q is built. The linear relation and the logarithm linear relation among RMR and Q and overbreak-underbreak are gained. It is fit to fact that the relation between the classification of RMR and Q is built according to overbreak-underbreak of tunnels. Lastly, the multi-correlation among overbreak-overbreak, surrounding rock classification and radius of tunnel are researched.

The time effect of the soil’s stress-strain relationship has a significant influence on the long-term settlement of pile-foundation. Long-term settlement of pile foundation includes at least two components: penetration of pile tip and compressed settlement of subsoil. By Mesri creep model, using the Mindlin stress formula to calculate the stress induced by the load of pile; and using Boussinesq stress formula to calculate the stress induced by the load of raft; a simple but practical method for predicting long-term settlement of pile-foundation was developed. The comparison between the calculated and true settlement demonstrates that this method is reasonable and useful.

Based on the local supervising data of air temperature decreasing period of Beiluhe testing segment of the Qinghai-Tibet Railway during the past two years, and through analyzing the ground temperature rule of the vent-pipe embankment, cast-detritus protecting slope embankment and heat preservation material embankment testing segments, and calculating the accumulating temperature of the above segments; the results show that the three engineering measures have some effects on protecting the permafrost roadbed. In some way, it can be used for reference in constructing the Qinghai-Tibet Railway in permafrost regions.

The researches and practice show that the permeability is often apparently related to direction, hence permeability is a kind of vector. The geological origins of directional permeability are expounded. Some confusable viewpoints, which occur when understanding and using the vector properties of permeability, are analyzed and put right. Also it is revealed that the resultant vector of two permeability vectors in two different directions can not serve as the rock permeability of the direction to which the resultant vector point; and the projection of a permeability vector can not be used as the permeability of the projection direction. Furthermore, A quantitative calculation model is deduced for anisotropic permeability. The horizontal permeability in any direction could be calculated by virtue of this model. Moreover, this calculation model of permeability could be used to compute the directional transmissibility in numerical reservoir simulation, and to design the well spaces in different directions for anisotropic reservoir.

Meso-scopic structural damage development during the triaxial shearing process of frozen soil was studied by computerized tomography (CT) technique. Analysis of CT-images and values during deformation shows that there is already a variety of initial structural damages, such as micro-holes, pipe-shaped holes and low-density regions before loading. The elastic damage only accounts for a very small scale in total damage, but viscoplastic damage for a great scale. There also exist the phenomena of structural strengthening and softening during triaxial shearing, similar to those during creep of frozen soil. The viscoplastic damage, which can not be determined by CT-values, behaves mainly in the forms of the changes of size and shape and unification of microscopic cavities, the slippages between soil particles and/or cemented ice particles.

Aiming at the blindness and controlling afterwards existing in the expressway soft ground design and construction, a method of dynamic simulation design was put forward to control the soft ground construction. According to the data achieved through soft ground monitoring, a simulation calculation was used to design the fill height and the filling rate of each construction stage, a loading project was done. Monitoring was going on through the process of construction. We analyzed the data achieved to amend geologic parameters used in the next step of simulation calculation. Carrying on this procedure time after time, dynamic simulation control and dynamic design of the whole process of construction is realized. The flow chart of the whole dynamic simulation design was established here. Problems of how to calculate some soil parameters such as consolidation coefficient by the monitoring data, and how to take the strength increase of the soft soil into account was solved in the dynamic simulation design too. Applying in the construction of an expressway, this method turned the construction from mode of controlling afterwards to the mode of controlling beforehand, avoided blindness and many accidents in the construction effectively.

Dynamic failures of rock masses under strong ground motion are common phenomena usually observed but lack of studies because of their complexity. Deformation failures of layered rock masses under strong ground motion are studied by physical simulation experiments. Horizontal ground motion with different amplitudes and frequencies is respectively operated on models with different structure characteristics to investigate dynamic failure of layered rock masses according to mutual relation between discontinuity orientations and seismic forces. The results indicate that deformation failures of rock masses have different forms and distributing characteristics because of different spatial relations between discontinuities & dynamic forces and different discontinuities strengths. Structure failure of rock mass is principal that can be classified into macroscopical failure and microcosmic damage, structure characteristics of rock mass is dominating factor of dynamic failure of rock mass; inhomogeneity is one of its outstanding characteristics that are similar with those of the rock mass suffered from strong ground motions at meizoseismal areas. More researches are badly needed to establish dynamic failure modes of rock mass and to carry out quantitative mechanical analysis.

The stability of the talus slope is important to its construction and operation. We draw a conclusion on site that it is a incised gully collapsing talus slope that are consisted of bedrock and unconsolidated deposit. There are evidence close up and turn around between the elevations of 1 360－1 450 m, the elevations of elevation which are contributed to its stability. The data that by using 3D numerical simulation (3D-Sigma and 3D-Flac) show that ⑴Stress field of the talus slope is main weight field, its stresses distributes is mainly controlled by lithology; ⑵ Latent sliding surface is the interface of talus and the bedrock and above it in some height. ⑶ The displacement is toward to limit surface; and the displacement of the middle-front part of the talus slope is large; ⑷ The front zone’s close up improves stress state and raises the stability of talus slope; ⑸ It is wholly stable, but it maybe occurs middle-superficial layer failure between the elevations of 1 472－1 610 m .

The TEXSOL reinforcement mechanism was analyzed theoretically. The influencing rule of several factors on TEXSOL reinforcement character was researched; and the defect of the existing experimental calculating formula of TEXSOL strength was analyzed. Based on a lot of experimental results, a series of empirical coefficients were determined. The relationship of influencing factors and TEXSOL reinforcement character was gained. The research shows that the increment of TEXSOL cohesive strength is related to the fiber toughness, fiber fineness and TEXSOL mixing ratio. The empirical formula of TEXSOL reinforcement was proposed. Finally, the straight-wall height method was extended to the design of TEXSOL retaining wall; and the proposed empirical formula was used to analyze the internal stabilization of TEXSOL retaining wall.

Solidification technology is an important way for reuse of dredgings; the influence of organic matter on the effect of solidification is a significant problem needs to make clear. Through laboratory study, a remarkable influence of organic matter content on dredging solidification effect was discovered; the relationship of organic matter content and unconfined compressive strength of solidified dredging was made clear; a critical organic matter content 4.3 % exists in dredging, when the organic matter content higher than the content, the adding of organic matter does little influence on solidification effect. According to this principle, a cement-gypsum solidification method is proposed to solidify high organic matter content dredgings.

Making use of the load and displacement curve of anchor rod (shorted for P-S curve) acquired in the field pull-out tests, we can make sure the ultimate bearing capacity of anchor rod; but we must proceed destructiveness experiment. By developing the mathematical model research of the P-S curve of anchor rod, the hyperbolic model and exponential model that predict the ultimate bearing capacity of anchor rod have been contrasted and analyzed referring to the data of pull-out tests of anchor rod; it is shown that the exponential model is better suited for simulating the P-S curve of anchor rod and predicting ultimate bearing capacity of anchor rod.

Through analyzing the landslide pattern of the slope in West Open Pit Coal Mine of Pingzhuang, a conclusion can be drawn that the weak interfaces is the main controlling factor of landslide. Considering the depth of anti-sliding pile is limited so that it can not control the potential deep-stated weak interfaces which will accumulate the potential sliding mass with the increase of mining depth, so another reinforcement method, using prestressed anchor rope to reinforce the deep-stated weak interfaces, is analyzed. The results show that this method can improve the strength of the whole rock mass obviously and erase the incipient fault of slipping along the weak interfaces. The practice of the mining area also proves that the prestressed anchor rope reinforcement is in good working order and meets the expectant result.

Erosion of the road embankment caused by rainstorm, is very serious in loess zone, even leading to road embankment collapse. There has rarely reported about the anti-eroding effects of geotexiles on road embankment so far. Based on detailed analysis on results of a series comparing test on anti-eroding effect of geocells, a conclusion is drawn that the using geocells is an effective way to improve road embankment’s anti-eroding ability. Finally, the anti-eroding mechanism of geocells is discussed.

A SMP—1 super mini-penetrometer was made for the interest of knowing the distribution and strength of aggregates in unsaturated soils well. The work principle and buildup of this apparatus is briefly introduced; and then the feasibility and availability of the application of the apparatus are demonstrated through the penetration tests with the samples of dough and expansive soils treated by lime. It is shown from the test results that the curve of the resistance force to the end of the needle versus depth during penetration can be presented and the strength distribution isoline maps of aggregates in any vertical section or horizontal plane of the defined cube-like blocks of the samples, which can show the intra-structural diversity and nonuniformity of samples, are obtained with the application of the apparatus. The successful manufacture of the apparatus, therefore, provides a new method for studying the distribution, inner structure and strength of aggregates in engineering soils.

The construction techniques of cast-in-situ concrete thin-wall pipe pile(referred to PCC pile) is introduced and tested based on the application of PCC pile in the soil improvement of Yan-Tong expressway, Jiangsu Province. The collapse degree of concrete, velocity of pile extraction, sequence of pile installation and fullness coefficient of concrete of PCC pile during construction are studied in detail. On the other hand, the methods of PCC pile quality detection are discussed; and the possible problems during construction and countermeasures are discussed too.

Based on WEBGIS platform, the paper presents a real-time warning system for regional geological hazards in Zhejiang Province which is formulated with precipitation and its forecasting data and geological hazard investigation data. The system concludes four subsystems: subsystem of geological hazard management; subsystem of spatial prediction and time warning; subsystem of application in illustrative regions and subsystem of hazard reduction and prevention. The main purposes are (1) to establish systematic digital geological hazard management of individual and regional geological hazard information including data and maps according to the subsystem of geological hazard system, which can serves for decision-making in administrative ways; (2) to establish a real-time regional geological hazard warning system in Internet which is strongly connected with weather information center. The warning information of Zhejiang Province is released timely through Web net in raining seasons. The key part of this system is geological hazard prediction and warning modes, which is realized with the combination of regional geological hazard zonation and dynamic weather information. This system is run during the rain season from May to July of 2004. It is evaluated by in-site geological hazard inventory that practical geological hazards are mostly occurred within the warned high risk areas, which gives good confidences of the models and system operations.

This paper presents the selecting of supporting pattern of pile foundations and applies the support vector machine to the deep foundation pit. It proposes the new approach to select supporting pattern of pile foundation and builds the model. The result shows that this approach is feasible and has wide application prospects.

While the elastoplastic finite element method based on the shear strength reduction (SSR) technique is employed to analyze slope stability, the overall factor of safety computed numerically is, in a certain degree, dependent on the criteria used for evaluating critical instability condition of slope. As usual, the convergence of the numerical computation of elastoplastic FEM is commonly employed in conventional studies. In fact, the convergence of the nonlinear analysis of elastoplastic FEM is controlled by a number of factors. Therefore the rationality and uniqueness of the numerical solution of the safety factor are in doubt. In order to examine the reasonability and applicability of various criteria including the convergence of numerical computations, the abruptness of the displacement or deformation at a certain characteristic location and connectivity of plastic zone, an example slope is analyzed by using the elastoplastic FEM based on the SSR technique. The computed results are compared with the solution of the Spencer’s procedure of limit equilibrium. It is shown that the safety factors computed by using the criteria respectively based on the abruptness of the displacement or deformation at a certain characteristic location and connectivity of plastic zone are almost identical to the solution of limit equilibrium method, while the elastoplastic FEM analysis based on the convergence of numerical computations may give an incredible estimation of the safety factor in some circumstances. Considering the feasibility and simplification in engineering practices, both criteria based on the abruptness of the displacement or deformation at a certain characteristic location and connectivity of plastic zone are suggested to be jointly used in the elastoplastic FEM analysis of slope stability.