With the creep test data of granite taken from Three Gorges, the existence of time-temperature equivalence effect (TTEE) of granite is investigated. Based on the creep test data at different temperatures, which are 20 ℃, 60 ℃, 80 ℃, 100 ℃, 200 ℃, 300 ℃, four-component viscoelastic Burgers model is presented to characterize the creep curves. The parameters of elasticity modulus and viscosity coefficient in the constitutive model at different temperatures and their functional dependences on temperature are obtained. Then, according to the basic theory of TTEE presented in research (I), the TTEE of granite is investigated through modifying the compliance curves with vertical shift function and checking the coincidence of the modified curves with horizontal shift functions. It is concluded that: ① Burgers model could appropriately characterize the creep property of granite in a short time scale. ② Both elastic modulus and viscosity coefficient in the Burgers model decay exponentially with temperature. ③ The coincidence of the curves at different temperatures after vertical shift modification and horizontal shift is fine, which indicates the existence of TTEE of granite. ④The master curves which reflect the long time scale test data at temperatures 20 ℃, 100 ℃, 200 ℃ are obtained.

Liquefaction strength tests for saturated stratified sands with different silty layer thicknesses were carried out by dynamic triaxial testing machine under constant stress amplitude cyclic loads. The deformation and mechanical properties for clean sand and stratified sand with different silty layer thickness were analyzed. The experimental results show that the development law of pore water pressure for stratified silty sands are different from clean sands due to the special soil structure; the liquefaction resistance strength of saturated stratified silty sands does not increase monotonously with the thickness of silty soil layer, but there is a critical thickness. However, the liquefaction resistance strength increases monotonously with the thickness increasing above the critical point; the critical shear strains are different under different liquefaction criteria and different cycle numbers, such as the critical shear strain under the criterion of =1.0 is larger than that under the criterion of =0.9. Besides, the critical shear strain should not be a constant under different earthquake magnitude and intensity. The silty interlayers influence the liquefaction characteristics of stratified silty sands greatly and can simulate the liquefaction characteristics of stratified sands in natural environment better.

The filter paper method and the pressure plate method are used for measuring the soil-water characteristic of Kunigel-V1 and Gaomiaozi (GMZ) bentonites. The soil-water characteristic curves (SWCC) obtained from the tests at different void ratios are compared. Relation between SWCC and void ratio and the effects of void ratio on the soil-water characteristic of bentonite are also analyzed. The results show that when the SWCC is expressed by the relation between suction and water content, the effect of void ratio on the SWCC is rather small at the range of higher suction; when the SWCC is expressed by the relation between suction and the saturation degree, the SWCC moves up and right with the decreasing of void ratio. That’s to say, the saturation degree increases with the decreasing of void ratio at a constant suction; and the change is nearly linear. On the other hand, when the void ratios are the same, the SWCCs of Kunigel-V1 bentonite and GMZ bentonite are almost the same. In other words, the soil-water characteristics of the two bentonites are quite similar.

Silt content increases significantly during the experiments of lime treated expansive soil. When the wet method is adopted, the soil maintains original structure and performances of silt features. If the water content at a lower level, the compaction power is lower than the structural damage and the compaction curve shows a dry density peak. With the increasing of water content, compaction power exceeds the structural damage and the compaction curve shows another dry density peak. Therefore, the compaction curves show instable bimodal phenomenon, which reduces the practicality and reliability of the compaction curves. However, the modified wet method is adopted to overcome the shortcomings of both wet method and dry method. The results provide an effective method for quality control of construction and quality evaluation of completion.

With the development of land reclamation, the seabed elevation level becomes lower and lower and the thickness of the reclaimed soil reaches 10 m from 2 m original; so that great deformation occurs during the vacuum preloading. The strength of a soil layer about 2 m to 3 m in the foundation surface is high after the vacuum preloading in the field, but below the depth of 3 m to 4 m, the strength of soil increases little. Through super-soft soil vacuum preloading model test, it is found that the PVDs have undergone a drastic distortion because of big deformation of the soil, so that the PVDs efficiency becomes lower and the soil reinforcement is ineffective. The PVDs are installed for a second time and made secondary reinforcement to the soil after the deformation of the reinforced soil reaches stabilization. The results show that the settlement of the soil develops more; the water content of the soil can be lowered further; the vane strength can be improved more; and the diminishing rate of the vane strength along the depth is greatly reduced. It is shown that the efficiency of PVDs reduces due to the deformation in the first installation; and it can not meet the foundation design requirements; using secondary PVDs installation can have better reinforcing effect. The study results provide basis for exploring a more effective method to reinforce deep reclaimed soil.

Stochastic medium theory is first applied to calculate the surface settlement induced by double-o-tube shield tunneling construction. Assuming the soil movement after excavation is non-uniform convergence mode, the calculation formula for surface settlement induced by ground loss is deduced with stochastic medium theory. As shown in analytical calculation, the predicted surface settlements are in good agreement with the observed settlements. The results of double circle overlay model method are obviously bigger compared with the field data. There is no consider the reduction amount of soil loss due to double circle overlap, so the amount of soil loss is much more than the actual. If reducing the double circle overlay model method according to actual soil excavation area, it can be found that the results are still higher than the measured values. It is indicative that the surface settlement induced by double-o-tube shield tunneling can not simply calculate by this method. The modified double circle overlay model method and the modified coefficient are presented. The calculated surface settlements using the modified double circle overlay model method are good accordant with the field observations.

The rocks cracks are in tension-shear stress state when excavated and unloading. Based on the analysis of stress and deformation for the crack in tension-shear sress state, the mechanism of its expanding is studied by linear elastic fracture mechanics theory and physical model test. The researches show that the frictional force along crack plane is vanished when cracks are in tension-shear stress state; the cracks expanding is started up in the direction of the fracture toughness KI of mode I tensile crack being minimal, and ultimately perpendicular to tension stress. The total displacement is parallel to tension stress under tension-shear stress state, the dynamic stress intensity factor of branching cracks tip in the process of expanding and its expanding length are solved based on energy and linear elastic fracture mechanics theory on the logical displacement hypothesis. The theory results are examined and certified by physical model experiment of some single crack under tension-shear stress.

Cast-in-place pile with expanded branches and bells by 3-way extruding arms (DX pile), a new variable cross-section pile, has obvious advantages in bearing capacity and settlement control compared to conventional pile. However, studies of bearing mechanism and settlement characteristic, especially group DX piles, are not sufficient. The bearing capacity and settlement characteristics of single DX pile and group DX piles are analyzed via in-situ model test. Special attention is paid on single and group DX piles comparison under same conditions; at the meantime, the single DX pile and conventional pile with the same pile length, diameter, and the same bearing capacity are compared so as to provide the theoretical references for the bearing capacity design of the DX piles in the engineering practice

Heavy tamping compaction is a traditional method in tamping construction of rubble bed. Some constraints in this method, such as small tamping energy and small dividing thickness, result in the low efficiency. A couple of improvements in the process of heavy tamping compaction are put forward. The proposed improvements are the increase in the tamping energy and the dividing thickness of rubble bed. Heavy hammer is first designed; then field contrast test of tamping stress and laboratory model test are carried out. The test results show that the new process is feasible. On this basis, the dividing thickness of rubble bed is increased to 4 m from 2 m. The construction results of the Songyu Harbour in Xiamen show that the improved process of heavy tamping compaction gets a good result; as the average compacting rate reaches as high as 14.85% and the efficiency increases significantly, so as to provide reference for similar engineering practice.

The hole rock is selected as a spesimen, and the thermal infrared radiation variation features of hole rock are experimentally studied in the process of loading by using uniaxial loading system and thermal imager, as well as combining the numerical simulation. It is revealed that the distribution of compression stress and tension stress on hole rock are symmetrical, which results in the symmetrical distribution of thermal image. The surface radiation temperature in tension stress area decreases and the radiation temperature in compression stress area increases. There is a fine corresponding relation between stress field and infrared radiation temperature field. In the later period of loading, rock appears fractures and the radiation temperature on shearing fracture is increasing; but the radiation temperature on the position of tension fracture is almost not changed. The fracturing type is closely related to the infrared radiation temperature variation. The rock fails finally along the shearing fracture; and the temperature-increase strip is the important infrared precursor of rock fracture and destabilization. The experimental results indicate again that the thermal imaging technology can detect the stress and catastrophe of rock

hrough a large number of physico-mechanical tests and microstructure analysis of soft soils in Nansha area, Guangzhou, China, 40 groups of physico-mechanical indices and microstructure parameters are obtained. Using data analysis ability of grey-relation analysis method and nonlinear mapping ability of artificial neural networks, a model for the relationship between physico-mechanical indices and microstructure parameters of soft soil is established based on grey-relation analysis and radial basis function (RBF) neural networks. In this model, grey-relation analysis is applied to preprocess data and extract key components as the input of the neural networks. RBF algorithm can fully utilize the information contained in the training data，adaptively choose the centers of radial basis functions, the widths and the weights of networks; therefore, the problems of determining node number of hidden layer and centers，slow learning speed and weaken generalization ability of traditional RBF neural networks when the input data are generous and complex are solved. Model A and model B show that this method can reduce the structure of neural networks, and raise efficiency of training and accuracy of prediction, and provide an efficient way to quantitatively study about relationship between physico-mechanical properties and microstructure parameters of soft soils.

The characteristics of unsaturated clay under different water contents and densities are analyzed based on the frost heaving and thawing settlement experiments. Influence of water content on frozen soil thermal conductivity is concerned; and attentions are particularly paid to the movement of freezing front. Moving speed of freezing front is connected with dry density and water content; water content has a significant effect on freezing front movement. Higher water content means faster movement for freezing front. The experiment and analysis of unsaturated frozen soil can provide references for the theoretical study and engineering application.

Evaluation of earth pressure is one of the key research subjects in soil mechanics and geotechnical engineering. The backfill displays anisotropic mechanical characteristics because of compaction in engineering practice; it is always at the non-limit state between the active and passive states. Classic Rankine and Coulomb earth pressure theories do not consider the effect of anisotropy and backfill deformation on the earth pressure. Based on a series of constant strain increment ratio tests, the unique relation between the earth pressure coefficient and the lateral strain constraint is established for anisotropic sand. On this basis, a method is proposed for estimating the earth pressure at the active side for anisotropic backfill sand under translational wall movement mode; and corresponding formulas are derived. Besides, the effectiveness of the suggested method is confirmed experimentally.

Geomechanical model test based on electromagnetic force is one of the newest efforts. Its theory and method test are established with electromagnetic force to simulate gravity or electromagnetic field to simulate gravity field. Geomechanical problem can be studied by the model test of electromagnetic force. Based on three principles of the similarity theory, the similarity criterion of test can be deduced. Using dimensional analysis and equation deduction, similarity criteria of the parameters are obtained as follows: , , , , , , . In the model, the time t and the geometrical dimension l reduce n times; the acceleration of gravity g amplifies n times; the similarity ratios of the other basic material physico-mechanical parameters such as ?，?，?，?，E，c，k，v，q，? are all 1. The geomechanical model test based on electromagnet force can use prototype material of the structure, which can provide convenience in model test operating.

Large shear deformation often occurs in the clayey soil-structure interface; and some defects and impurities near the interface may affect the seepage safety. By using a seepage test device for interface, seepage characteristics of clayey soil-structure interface under large shear deformation were studied. The conditions of the interface with construction defects and impurities were simulated and the seepage characteristics were compared with that of homogeneous clayey soil. The effects of normal stress, shear deformation and hydraulic gradient were analyzed. The results show that the permeability of the interface with defects decreases with large shear deformation; while the permeability of the interface with impurities decreases with shear deformation increase at the beginning and then increases after a certain shear deformation. The permeabilities of interfaces with defects and impurities are higher than that of homogeneous clayey soil.

The deformation features, mechanical parameters and failure characteristics were obtained based on the results of triaxial unloading tests of limestone. It is shown that the evolution of volumetric strain is determined by lateral strain under unloading condition. Failure modes of rock could be classified into three types: primary shear failure, conjugate shear failure and splitting-shear failure. The failure stress difference decreases with unloading velocity increasing under the same initial confining pressure. However, it increases with the initial confining pressure increasing under the same unloading velocity. The rebound value of axial strain increases; while the lateral strain jump decreases with the initial confining pressure increasing at the same unloading velocity. The cohesion of rock increases but the internal friction angle decreases with unloading velocity increasing

Inferior strength, which is caused by salt expansion, dissolution and water absorption of inshore saline soil, will be prevented with the help of reinforcement with wheat straw and lime. First, some samples are prepared, which including saline soil, reinforced saline soil with wheat straw, lime-saline soil, and reinforced saline soil with lime and wheat straw as the way of reinforcement in whole, upper and lower position respectively. Then, unconfined compressive strength tests of 50 mm, 152 mm (heavy compaction specimen) and 102 mm (lightly compaction specimen), as well as triaxial shear test of 61.8 mm in diameter are carried out. Finally, strength increment, ratio of deviator stress, and cohesion increment are defined to evaluate the reinforcement effect. The results show that: 1. Reinforcement raise the strength and the anti-deformation of soil. 2. Reinforced action increase largely the cohesion of soil, and the reinforcement in lower position can contribute a more effective role. 3. Strength of reinforced soil is contributed mostly by wheat straw and lime; the strength in water depends on chemical reaction of lime. 4. Lateral deformation of reinforced soil is restricted by means of wheat straw within a lower confining pressure, and that is supported jointly by reinforcement and confining pressure within a higher confining pressure. Reinforcement with wheat straw is one of the suitable means for improving strength and anti-deformation of inshore saline soil.

It is important to know the terra-mechanics characters of lunar soil for designing reasonable wheels and running gear of the lunar rover. The simulant lunar soil is prepared firstly, and it could be used for the basic test of the terra-mechanics on moon. The elastic modulus is 48.8 MPa from the triaxial tests by calculation. The hardness of simulant lunar soil is tested by penetrometer; and the results show that it is less than that of the black soil and close to that of the sand. Using the plate-sinkage-test to measure the vertical strength of lunar soil, the n (sinkage exponent) is 1.13, K (modulus of deformation) is 1 056 kN/mn+2 by calculation; and the vertical strength of simulant lunar soil is increased with the increase of the n and K by analyzing. The horizontal shear strength can be measured by means of a shear-test, and k (shearing strength displacement modulus) is 1.2 cm by calculation. The k has little influence on the shear strength; but its peak will move backward; and the shear strength is increased with the increase of the internal friction angle and cohesion. The results can supply the reference to evaluate the traffic ability of the lunar rover.

At present, the Q system supporting design method based on Norwegian tunneling method is widely used in single layer lining, but this method involving 6 parameters, which can’t be tested accuracy before or during cnstruction and the testing cost is high. So the Q system supporting design method is not suit for China’s single layer lining design. At this background, the design principle and design methodology for single layer lining based on yield approach index and the support theory based on broken rock zone are put forward; and the engineering practice combining with Dabieshan tunnel inclined shafts No.2 on the Hefei-Wuhan railway is executive too. During the research, engineering condition, hydrogeology condition and physico-mechanical indices of surrounding rock where the tunnel located must be got by geological prospecting at first; then the supporting parameters of single layer lining and mechanical index for shotcrete is presented which will form the structure’s pre-design. During the actual process of construction, according to the broken rock zone range which is field tested and then use support theory based on broken rock zone to modify the design, a complete single layer lining design system will form. The practice shows that the design method of single layer lining proposed is economical and applicable; and the interference for construction is low which suits information construction. On the other hand, the single layer lining structure completed is safe and reliable, and it will make notable economic and social benefits in engineering application; it is worthwhile to be popularized.

In order to study the early warning index of landslide, a landslide database composed of 31 typical rock landslides is established; and based on the database a landslide case-based reasoning system is developed using engineering analogy and fuzzy comprehensive assessment model. The feature attribute of landslide is divided into 6 items, including failure mode, dip angle of slip plane, slip-zone type, rock mass structure, slope angle, inducing factors in landslide (rainfall, groundwater, reservoir impoundment, excavation, blasting and seismic peak acceleration), whereupon the characteristics of properties of slope is represented by 11 eigenvalues. The most similar slopes are searched from the database using theory of similarity based on ratio method; and the suggested warning criterion is given based on engineering analogy; and then revised criterion is get based on fuzzy comprehensive assessment model. Taking JinpingⅠhydropower station for example, five landslides that are most similar with the slope at left bank of JinpingⅠhydropower station are got. Anjialing open-pit mine landslide and landslide in eastern open pit in Daye among the result have intact deformation monitoring data, so in terms of four periods the early warning criterion of the slope at left bank of JinpingⅠhydropower station is given, based on deep analysis of deformation and failure process of the similar slopes. A fuzzy comprehensive assessment model is established to revise the criterion mentioned above; and exact interval of (1, 1.2) mm/d is given which determines the displacement rate threshold when the slope at left bank of JinpingⅠhydropower station develops into the accelerated deformation stage.

Inspired by the migratory behavior in the nature, a novel migrated particle swarm optimization (MPSO) algorithm is proposed. In this new algorithm, the population is randomly partitioned into several sub-swarms, each of which is made to evolve based on particle swarm optimization with time varying inertia weight and acceleration coefficients (LPSO-TVAC). At periodic stage in the evolution, some particles randomly migrate from one complex to another to enhance the diversity of the population and avoid premature convergence. It further improves the ability of exploration and exploitation. Simulations for benchmark test functions illustrate that the proposed algorithm (MPSO) possesses better ability to find the global optima than other variants and is an effective global optimization tool. Then the new algorithm is applied to parameters inversion of rheological model of rockfill. The results show that MPSO remarkably improves the calculation accuracy and is an effective tool in parameter inversion of complex model.

For the high rockfill dam, whether too low vertical earth pressure or higher pore water pressure exists in the corewall or not has great significance for the security and stability of dam during construction as well as the impounding period. Combined with the construction schedule and procedure information, based on the monitoring data of gravelly soil core wall stress during the construction period, the soil pressure and pore water pressure in gravelly soil corewall during construction period are analyzed in time, space and effect factors respectively, with a view to improve design theory and construction measures of high rockfill soil corewall dam. Soil pressure primarily relates to soil bulk density, soil column thickness and the arching effect and symmetrically distributes along the dam axis. The strongest arching effect site is around the 1/3 height of corewall near the dam axis. At height with arching effect, the soil pressure is hump-shaped distribution and the minimum soil pressure is near the dam axis. Pore water pressures primarily relate to soil pressure and water content. At the dam filling process, to avoid the generation of excessive pore water pressure and reduce the impact of arching effect, the water content of the corewall material and the upper and lower dam shell should be strictly controlled.

The characteristics of surface ground motion are apparently affected by the nonlinear behavior of site soil under strong motion input. The soil nonlinear behavior is firstly discovered by geotechnical engineers in laboratory tests; and then the seismologists confirm it by analyzing record data from the strong motion observation. Generally speaking, the site soil nonlinear behavior becomes more significant while the earthquake excitation increases; however, for different site types and same excitation level, there would be different site soil nonlinear behaviors. A method is proposed to determine the corresponding earthquake motion input thresholds for typical sites based on the relationship of shear wave velocity variation ratio and earthquake excitation.

In the management of the karst fissure water, the 3D extension law of the water-bearing formation and the hydraulic cross-connection of fissures which are difficult to find out are key factors of the construction time limit and the cost of engineering. The ground penetrating radar (GPR) detection in karst area is affected by strong interference, multiple solutions, signal distortion; so the grid method is put forward based on the probability theory. Based on the electromagnetic wave propagation theory, the energy distribution law of the reflection and refraction on the interface of the water-bearing formation is researched. The mechanism of the water-bearing thin bed on the low frequency reflection signal of radar is analyzed. The criteria of the detection of water-bearing fissure in the karst area are discussed. Combined with the example of the karst-water management in the Qiyueshan tunnel floor, the applications of GPR to the detection of the water-bearing extension law and the choice of the best grouting hole are described. The conclusions can bring the ecological, safe and economic benefits; and the research can provide a reference for similar projects.

Time-history analysis using dynamic FEM is employed to compute the seismic response of Ahai concrete gravity dam at the Jinsha River subjected to design earthquake loading. The hydrodynamic pressures and dam-foundation interaction are considered in the FEM model; and the foundation radiation damping effect of the seismic motion energy dissipating towards infinite domain is simulated as well. Firstly, the complex numerical simulation results are validated by comparison of dam body’s maximum inertial forces between time-history analysis and spectrum method. Then, the following evaluation of the sliding stability of the dam can be conducted. The time history of anti-sliding safety factor is obtained using stress integration along the dam-base sliding interface. Because the minimum value of safety factor histories is 1.146; it can be concluded that the Ahai dam has a relatively enough high capability for earthquake resistance that the reinforcement to improve the anti-sliding stability is not needed. The outcome of this study should be of interest and useful to professionals involved in the design of similar large gravity dams.

The design idea of solving high-water pressure effect on railway tunnels is brought forward by using water releasing segment lining. Considering the influence of seepage field on stress field of the ground field, the external loads calculation formula of segment lining by treating water load as permeation bulk forces are established; the interrelations between infiltration coefficient of surrounding rock and maximum discharge volume, the interrelations between controlled discharge volume and contact stress behind the lining are discussed; and the influence laws of surrounding rock conditions on effective stress and contact stress behind the segment are studied. Finally, the method is contrasted with a simple method which calculates segment lining external loads through treating far-field water loads as surface forces in order to evaluate the feasibility of the simple method. The results show that two calculation results by treating water load as surface forces and permeation bulk forces have a good approach only in given conditions, so the former method only can be a reference in selecting segment lining external loads

Considering compression of solid grain and pore fluids, viscous-coupling interactions and inertial force of fluids, the dynamic governing equations for unsaturated soils are established by adopting an exact constitutive formula of saturation. These equations are highly versatile and completely compatible with Biot’s wave equations for the special case of fully saturated soils. The governing equations in cylindrical coordinates are firstly transformed into a group of state differential equations by introducing the state vector. Then the transfer matrix for layered media is derived by means of a Hankel transform. Using the transfer matrix followed by boundary and continuity conditions, solutions of steady state dynamic response for multilayer unsaturated soils are obtained. Numerical examples show that the displacement of the ground surface is mainly affected by stratum within critical depth. The relative position of soft and hard strata has a significant influence on displacement. The displacement of the ground surface increases with saturation degree since dynamic shear modulus will decrease distinctly for most soils, which is the key factor to determine displacement amplitude.

The 2008 Wenchuan earthquake caused destructive geologic hazard such as mountain landslide, collapse and debris flow in the mountainous area. Meanwhile, the liquefaction occurred extensively in the Chengdu plain that was mainly underlain by gravelly soils. Six typical liquefied sites were selected for drilling and field test in order to understand the features of liquefied soil and verify the feasibility of the liquefaction evaluation method in the Code for Seismic Design of Buildings. The results indicate: (1) The liquefied soils of six typical sites range from sand to gravels, two of which are sand and the rest are gravels. (2) The liquefied soil layers are loose and non-uniform with gently grain size distribution curve and large coefficient of uniformity; and the liquefied sands are well-graded soils and liquefied gravels are not. (3) The liquefaction evaluation method in the seismic code predicts one of the six typical sites as non-liquefaction site. Moreover, the code method is not feasible for gravels liquefaction assessment, because the standard penetration test (SPT) is impeded through the gravelly soils by big cobbles

Based on the good characters of creep property, low permeability and self-healing of damage, salt rock has been widely used in energy storage of oil and gas. Nowadays, most researches are concerned on the mechanical properties of salt rock at home and abroad; but the studies about risk analysis of the salt cavern storage are still few. So in order to explore the risk mechanism of salt cavern during the operational period, with the demonstration project of the Jintan oil-gas storage of salt rock in Jiangsu Province, the risk factors during the operational period are identified. Fault tree analysis (FTA) is applied to establishing the analytical models for cavern failure, surface subsidence and storage leakage. Then the minimal cut sets and structure importance are used to sort the risk factors for their influence level. At last, FTA is evaluated to provide guidance for further risk assessment and control during the operational period.

Open trenches are continuous barrier, which are widely installed for efficiently reducing man made vibration. The 2D grid method using displacements variables is flexible and efficient to calculate wave propagation problems, combining the merits of finite elements method and finite difference method. Using the method, the parametric study is conducted herein for vertical vibration isolation by open trenches in layered ground under traffic loading acting on the top of an embankment. The rigid upper layer with soft lower layer ground model and soft upper layer with rigid lower layer ground model are considered respectively. The results show that the width of the open trench has little influence on the screening effectiveness. The depth and location of the open trench are most crucial for the screening effectiveness and they associate each other; so the value of them should be determined comprehensively. The depth of the open trench is equal or close to the thickness of the upper layer is detrimental to the vertical vibration isolation. Higher embankment can give rise to bad influence for vibration isolation in vertical direction.

Based on the settlement data of the piled raft foundation in 88-storey, 4 m thick raft of Jinmao Building and 101-storey, 4.5m thick raft of Shanghai World Financial Center (SWFC), it is demonstrated that piled raft foundation is a real elastic body. Meanwhile, the eccentric compression formula and method on interaction between superstructure and foundation (mixed method) are used to compute the load on pile top of piled raft foundation for two superhigh buildings just mentioned and 121-stroey, 6 m thick raft of Shanghai Tower which is under construction and compare each other in detail. The computed results have shown that the mixed method used is feasible and reasonable. It is hoped that the article 3.1.3 in China Technical Code for Building Pile Foundations (JGJ 94 – 2008) can change the traditional conception to use the eccentric compression formula for computing the load on pile top of piled raft foundation.

Nondestructive testing with stress wave in piles and anchorage bolts is a kind of quick and effective detection method based on the one-dimensional wave theory; stress wave velocity is the basic parameter for quality assessment; the researchers and engineers often confuse the wave velocities in piles and anchorage bolts, hence incorrect assessment in practical detection. Therefore, by using wave velocities in free bolt and standard concrete sample under different curing ages as references, comparative study of stress wave velocities in a pile and an anchorage bolt is made based on low strain wave reflection method. The results indicate that the wave velocity in the pile is larger than that in the standard concrete sample; the wave velocity in the anchorage bolt is smaller than that in the free bolt but larger than that in the pile and the standard concrete sample; the wave velocities in the pile and standard concrete sample vs. curing age and strength are nearly ascending exponential relationship; while the wave velocity in anchorage bolt vs. curing age and strength is nearly descending exponential relationship.

One of the key procedures in statistical joint modeling is the determination of the joint size distribution. The mathematical features of the Poisson point process was considered. When the joint diameter distribution is continuous, the trace length lower bound must be zero; and the upper bound must be equal to the joint diameter upper bound. Since any continuous function could be fitted by a polynomial with high accuracy, a polynomial trace length distribution and constraints were proposed in the infinite sampling window for the Poisson disc joint model. Santalo closed-form integral solution was used to derive a closed-form expression for the equation, which determined the trace length distribution from the joint diameter distribution proposed by Warburton. Based on the polynomial trace length distribution, an analytical equation was derived to estimate the joint diameter distribution, and the complex numerical methods were avoided. The analytical equation was verified by the formula proposed by Priest. Based on the characteristic of the probability density function, a method for estimation of diameter distribution range was proposed, and the joint diameter lower bound was inferred by small step search algorithm. The inference method was checked for validity through Monte Carlo simulation.

Aiming at the characteristics of dangerous rock mass reinforced by prestressed anchor cables, displacement field and stress field distributions are simulated under different seismic loads; and based on three typical sections of a reinforced dangerous rock mass project, dynamic response and variations are revealed. The analysis results show that the displacements and stresses of the reinforced dangerous rock mass increase obviously with the increase of seismic dynamic peak acceleration (PGA) and characteristic period of response spectrum (Tg). Range of stress concentration expands; probability of surrounding rock damage increases and stability decreases. The results can provide theoretical basis and practical reference for aseismic reinforcement and disaster mitigation of dangerous rock mass.

Changshao Expressway tunnels with small spacing have complicated and special topographies; especially at the region of outlet, the provincial expressway S102 is only 5 meters over the vault of the left tunnel; and the right tunnel is pressed by an unsymmetrically pressure. In order to study the effects of excavation types on surface settlement and stability of surrounding rockmass, a three-dimensional model which is corresponding to realistic landform is built to simulate distribution of plastic zones, deformation of surrounding rockmass and surface settlement by three different excavation types which are bench cut method, core rock cut method and single-side drift method. Two practical excavation methods are recommended after simulating. Comparison of surface settlement is made between simulating result and field observations. The results show that bench cut method can be used to traverse provincial expressway. The surface settlement during excavation is small and surrounding rockmass is stable.

The preferred structural plane theory has been applied to geotechnical engineering practice gradually. The fuzzy comprehensive evaluation model based on matter element method is proposed and applied to determine the preferred structural plane of rock for the first time. The states of structural plane are regarded as the objects of matter element; geometric parameters and physical parameters for evaluation as well as the corresponding fuzzy values are used to construct the composite fuzzy matter elements. The evaluation of preferred structural plane is made by calculating the relevancy. The model can deal with the uncertain factors during the preferred structural plane calculation, such as rock and soil characters, scale, occurrence, fractal indices and active state; the model provides a new way for evaluating the preferred structural plane of slippery rock. The shortcomings of traditional methods, only considering the quantity predominance but without the quality predominance are overcome in the model; and the evaluation of rock structural plane is more reasonable. This article introduces the basic theory and calculation steps of the fuzzy comprehensive evaluation by matter element method. Through introducing basic theory and operating steps, a case study is given. The model effectively ensures the objectivity and compatibility in the calculation of engineering preferred structural plane and greatly improves the calculation accuracy and efficiency.

With the Western China development, more and more larger and deep karst tunnel will be constructed with the risk of water inrush and mud gushing in the Western China karst area; and the model and type of water inrush are so complex for the uncertain attribute of concealed water body, such as its position, scale, etc.; and the risk coefficient is very high for the tunnel face. Under the effect of especially big water bearing structure, water inrush of tunnel face happens when the excavation face enters into the minimal distance of safety thickness; and the catastrophe characters of water inrush are obvious. According to the catastrophe phenomenon, the effect of construction condition on the catastrophe characters of water inrush has been analyzed by the numerical method. With the hypothesis of circular tunnel, a fold catastrophe model of water inrush for tunnel face instability has been established; the criterion condition and minimal safety thickness have been given through analyzing the total potential energy function of tunnel face structure; based on the analysis of evolution path of catastrophe controlling parameters, the measures for preventing water inrush have been put forward, of which the feasibility has been proved with an engineering example of water inrush.

Uncertainty measure theory and dependent function are combined rationally and then applied to evaluating underground cavern rock quality. According to influence factors and grading standards of underground cavern rock quality, uncertainty measure functions of evaluation indices are obtained using the uncertainty measure theory. Dependent function is used to calculate weights of the evaluation indices of underground cavern rock quality. Credible degree recognition criteria are used to evaluate underground cavern rock quality. Finally, the comparative analysis is made with examples. The results show that the uncertainty measure method is reasonable and reliable; and it is a new method for evaluating underground cavern rock quality.

To study two-phase horizontal displacements of strata during tunnel excavation, specific areas are tested in Guangzhou Metro No. 2 and No. 8 extension project, combining with the numerical simulation with ABAQUS. The results show that there are different laws of two horizontal displacements U1 (parallel to the tunnel) and U2 (perpendicular to the tunnel) at different phases. The numerical analysis further demonstrates that in the circular region of one time tunnel diameter, the maximum of U1 is even bigger than U2. During design and construction stages, both the two horizontal displacements should be considered.

he effect on existing metro station structures caused by the construction of new risk underground project is studied by the finite element program and the finite difference program. The analysis of displacement caused by the construction of new contact channel No.3 between double-floor windtunnel and southwest entrance structure is expounded on the characteristics of safety evaluation of approaching project construction using different numerical methods. The evaluation conclusions are produced by checking the carrying capacity of existing structures combined with the survey of existing structures status. The displacement control indices are proposed that the settlement and uplift of the ground surface should not exceed 7 mm & 8 mm, respectively; the uplift displacement of the station soleplate and the relative uplift displacement of structures on both sides of settlement joint should be controlled in 7 mm & 2 mm, respectively; the uplift displacements of the tracks and track cross level should not exceed 5.8 mm & ±0.6 mm, respectively. The existing metro structures will be safe after the new-built tunnel is constructed if displacement controls are in the above-mentioned ranges.

Based on the experimental results of creep tests under step loading in the plane strain compression, the creep behaviors of non-reinforced and geogrid-reinforced sands have been investigated. It is found that the creep deformation is affected by the initial stress level and the initial creep strain rate in a given creep loading stage. When monotonic loading is restarted from the end of each creep loading stage, the stress-strain relation shows a very high tangent stiffness. A nonlinear finite element analysis (FEA) incorporating the unified three-component elasto-viscoplastic constitutive model for both sands and geogrids is developed. The FEA can simulate the whole process including the monotonic loadings at a constant strain rate and the creep loading stages. By comparing the simulated results with the experimental results, it is shown that the developed elasto-viscoplastic FEA can simulate the creep behaviors of non-reinforced and geogrid-reinforced sands very well, especially for the high stiffness following a creep loading stage.

The finite elements with joint net is a powerful program which has the function of modeling actual joint net of rock mass slope, it not only permits in-situ statistic parameters of the joints to be input into the model directly, but also gives joints the right to yield according to a certain criterion and thus can better simulate the real rock mass structure of the toppling slope and failure pattern. The stability analysis method of the toppling slope and open questions are discussed; the function and input parameter of the finite elements with joint net are introduced; and its some advantages for stability analysis of toppling slope are explained. A case of toppling slopes from Cihaxia hydropower station at the upper reaches of the Yellow River is calculated using this method to analyze its stability and failure pattern. It is shown that the finite elements with joint net is an effective and matter-of-fact method for the stability analysis of toppling slopes

Inner scale ratio is a ratio between minimum crystal structure of material and its specimen size. Rock and soil material, being a type of different sizes mineral particles assembler under microscopic conditions, contains different scale raw faults. These size features of material structure will affect accuracy of rock and soil material characteristics test results. That is to say there exists inner scale ratio in rock and soil materials like that of metal material. So virtual uniaxial compression test done by inner embedded fish language of particle flow code is used to study inner scale ratio of geotechnical material. Twelve numerical specimens with twelve types of grain size such as 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 mm are designed and tested. According to failure shape and stress-strain curve of these specimens, effect of inner scale ratio on test results is analyzed. It is found that the computing time increases dramatically and computing efficiency decreases sharply if grain size less than 0.4 mm; and that test results tend to stability and accuracy if inner scale ratio less than 0.01, so as to prove existence of inner scale ratio in rock and soil material. Size effect in geotechnical material is reflection of inner scale ratio.

Due to the rapid increase of traffics, more and more early-built expressways will be reconstructed. There are always several key technical problems for expressway widening on soft foundation, in which determining how to treat the foundation of the new road according to the old road foundation treatment methods is the most important. Effects of the different foundation treatments on road deformation are analyzed numerically according to a practice of expressway widening. Results show that the plastic drainage board used in the new foundation enhances the old road deformation greatly during widening; while the new foundation with composite foundation produce less settlement of the new and old embankment after construction and disturbance to the old road during widening. At the same time, the distribution of the horizontal displacements in foundation provides the theory base for using the stress isolation wall to reduce the deformation of old road resulting from the new embankment. The wall depth depends on the depth of the horizontal displacement concentration zones. In addition, the impact of consolidation degree of the old foundation on the deformation of the existing road during widening is insignificant when the composite foundation is used in the new foundation.

Numerical simulation was conducted to study the propagation properties of torsional guided wave in grouted rock bolts. Finite element models of a free bolt and a grouted bolt were established; and torsional guided waves with frequencies of 20-60 kHz were excited at the top of the bolts. The numerical results of guided wave velocities in the free bolt and in the anchoring section of the bolt agree well with the theoretical results. The result proves that the finite element method is an effective way to simulate torsional guided wave propagation in grouted rock bolts. The results of numerical simulation show that both the attenuation values of torsional guided waves in the free bolt and in the anchoring section of the bolt increase linearly with the increase of excited wave frequency. Meanwhile, the reflection amplitude of guided waves from the upper interface of the grouted rock bolt decreases. Torsional guided waves attenuate greatly in the anchoring section of the bolt; and reflected waves from the embedded end of bolt are not able to be captured; as a result, torsional guided waves are not applicable for bolt length testing. When the elastic modulus of grout material increases, the amplitude of upper interface reflected wave increases; so the upper interface reflected wave can be used to evaluate the elastic modulus of grout material.

According to the execution situation of the tunnel project, the theory of elastoplastic mechanics and the seepage law of groundwater are taken into account; a mathematical model considering seepage-stress coupling of the tunnel is established; seepage and the stress field around the tunnel in different working states are simulated by applying Comsol. The results indicate that during the process of excavation without any measures, deformation of the soil around the tunnel occurs; the deformation of the rock and the settlement of the ground are large; the buildings nearby are in danger and the groundwater infiltrates into the tunnel; the project can’t be conducted; after grouting, the deformation of the rock around the tunnel is reduced and the settlement of the ground is controlled; then the buildings nearby are safe and the tunnel excavation can be processed safely.

The 3D geological model of Wengfu phosphate mine is built with SURPAC software; and the interaction between the goaf and open cut mining is calculated by the fast Lagrangian analysis of continua in three dimensions (FLAC3D) through the interface program; and the monitoring points of slope and goaf are set in order to monitor the stress and displacement. The calculation results show that the goafs markedly change the stress distribution of slope and around goafs and cause the horizontal displacements of goafs to increase obviously. The goafs also change the vertical displacement and evidently influence the regions between goafs and cause the rebound displacement to decrease. The stresses and displacements appear regularity changes. The goafs evidently change the distribution of plastic zones. To the slope with goafs, the regions of plastic zone decrease with the slope excavation but appear tensile failure zone on the slope surface; and the goafs cause the safety factor of slope to reduce.

In order to obtain earthquake safety factor of surrounding rock of tunnel, using FEM software ANSYS, firstly, modal analysis is done by adopting the model under the horizontal earthquake action; and then mass damping coefficient and stiffness damping coefficient are obtained. Secondly, the horizontal support reaction force along the vertical borders is obtained by the static analysis. Thirdly, for considering the gravity influence in dynamic analysis, structure gravity is become into temperature boundary condition; and the temperature of each node in model is obtained by thermal analysis. Finally, adopting the dynamic analysis model of cantilever beam, and inputting into the node temperature which is obtained by using thermal analysis, and applying the level support reaction force along the vertical borders, cohesion c and friction angle ? in plastic zone are continuously discounted until the calculation is not convergent; and then the earthquake safety factor of surrounding rock of tunnel is obtained. Numerical example result shows that this approach is feasible, the measure that the structure gravity is become into the node temperature solves the difficulty that the structure gravity can not be considered in previous dynamic analysis; and so a theoretical basis is provided for dynamic safety factor calculation and engineering application of surrounding rock of tunnel under earthquake.

The ancient ruins, Shiguan gate attached to rock and soil mass, is a part of rock and soil mass; so geotechnical analysis is used to study of its damage mechanism. In the "5.12" Wenchuan earthquake, local cracking and dislocation phenomena occurred in Shiguan gate of Diaoyucheng ancient battlefield ruins in Hechuan of Chongqing. Geological survey shows that the Shiguan gate is under complicated geological conditions like landslides, cracks etc., so geological model of Shiguan gate is sampled and the fast Lagrangian analysis of continua in 3D (FLAC3D) is used to make 3D simulation of the seismic dynamic response and analyze damage mechanism of Shiguan gate. Simulation results show that the stress concentration obviously occurs in Shiguan gate and displacements appear obviously under the conditions of seismic waves. The damage of Shiguan gate results from various geological factors. "5.12" Wenchuan earthquake is induced factor, geological structure like landslides, cracks etc., is the main reason; the reduction of its own intensity is the internal reason. The reliable scientific basis of repair and design of Shiguan gate is provided by the the simulation results. It has certain study significance and promotion value.

The surface drain is one of the widely used measures in landslides control. Based on the coupling model of infiltration and runoff under rainfall, the drain model of surface drain ditch is realized by adjusting the slope gradients of the runoff control equation. The model is easy to understand and program composition. Furthermore, the seepage field, runoff field, the infiltration capacity and infiltration process are simulated for five typical landslides. The results show that when the rainfall intensity is smaller compared to infiltration rate of the soil, the surface drain should be set in front of the more penetrable slope segment to cut off the runoff in the upper and reduce the infiltration capacity; while the rainfall intensity is larger compared to infiltration rate of the soil, the effect of drain is not evident.

The feasibility of the monitoring technology of acoustic emission (AE) accompanying the fracture of coal and rock mass is discussed based on the analysis of coupling relationship between the damage failure and acoustic emission; and then the expression of rockburst risk assessment using acoustic emission index and its determination methods as well as classification of risk rank are put forward. The acoustic emission characteristics of coal samples under uniaxial compression are tested and obtained in the laboratory in order to provide reference for on-site application. Finally, the effects and limitations of Polish ARES acoustic emission system at rockburst mine hazard are analyzed.

t present, the most critical question in monitoring slope engineering is to find a new technology which can be suited for long-term and fixed-point situation, and it needs a lower-cost, higher precision and longer distance. Charge coupled device (CCD) is the technology which can get the information about slope stability by the mutual transformation of photoelectric signals. Compared with the traditional monitoring instruments, CCD has some advantages in accuracy, timeliness and cost. Meanwhile, it could achieve remote wireless control. So it significantly saves manpower and resources that required to monitoring. Based on exploring the working principle of the CCD micro-deformation monitoring system, it has been applied to the K101 slope of Zhuji-Yongjia expressway for a long-term monitoring; after a period time of work with GPS and total station together, it is shown that the data by CCD is favorable in precision and stability; and it is also demonstrated that the CCD micro-deformation monitoring system is suited for long-term monitoring of slope for a good effect.

Locating of gas-bearing structure and dynamic monitoring are two key problems in methane tunnel exploration. As far as methane found in Jijiapo Tunnel in the Three Gorges Dam highway, using geological survey, geological prediction in construction (geophysical prospect and geological drilling), comprehensive gas monitoring and other means of investigation are adopted to analyze gas-bearing structure, study formation cause of gas, and predict gas feature of surrounding rock mass in front of the cutting face and determine dangerous position. It is concluded that gas in this tunnel is characterized by disperse, low density and small volume. The gas flows through fissures and pores in rock mass without tectonic condition for large gas-bearing structure. Comprehensive survey can help to improve predicting accuracy and provide reliable geological support, and can be of great guidance to construction of similar tunnel project.