bluuebunny/crossref_metadata_2025 huggingface dataset:
Applications of Modified Equivalent Load Method in the Possibility of the Transportation of Large Equipment
Authors: Kang Jun Tao , Zhang Hui Hui
Published: May 2011

When the transport vehicles of large equipment pass through bridges, the main check-calculation coefficients affecting the bridge bearing capacity are the load transverse distribution coefficients, impact coefficient and load safety coefficient. Base on these affecting factors, this paper put forward a discriminant for modified equivalent load method. The triangle influencing line method is applied in measuring the equivalent load of commonly used vehicle plates for transportation of large equipment. Finally this seeks to verify and modify the accuracy and convenience of equivalent load discriminative method through engineering examples and thus suggests a concise and practical method for engineers and technicians： to conduct feasible study for bridge transportation for large scale equipments.
Vertical Load-Carrying Natural Frequency of Railway Double-Track Steel Truss Continuous Bridge
Authors: Ren Jian Ying , Li Wen Ping , Su Mu Biao
Published: May 2011

The railway double-track continuous bridge vertical load-carrying frequency is theoretical derived with the vehicle-bridge system mode1. The vertical load-carrying frequencies of the3×64 m through stud welding railway steel truss bridge are calculated, when two trains with 20 same high-speed passenger vehicles are traveling on the bridge from both ends. The change regularity of this double-track continuous bridge vertical load-carrying natural frequency with two trains on it is similar with the single-track simply supported bridge and this bridge vertical load-carrying natural frequency only one train on it. This bridge vertical load-carrying frequency when two train on it is smaller than that only train on it. The maximum deviation percentage between the vertical load-carrying natural frequency and the vertical natural frequency is 6.0452%. The vertical load-carrying frequency can be replaced by the average value.
Study on Disease Analysis and Reinforcement Technology of Truss Arch Bridge
Authors: Kang Jun Tao , Wang Nan , Liu Chao Zhi , Chen Chang Wu , Li Ling
Published: May 2011

Based on investigation and analysis of the diseases of Sujia river truss arch bridge, putting forward corresponding the reinforcing measures in accordance with the cause of disease. The results indicate that it is feasible to resume the bridge carrying capacity with pasting CFRP, pasting steel plate replacing bridge deck. It can be a reference to the other similar bridges.
Research on Construction Control Analysis for Pretensioned Structure
Authors: Wu Jie , Yang Yong Hua , Luo Xiao Qun
Published: May 2011

The theory of geometrical nonlinear analysis is introduced. The sag effect is considered by the multiple-straight truss elements. The unstress length which is modeled the tension force of cable is figured out. Three kind of positions where the new elements are activated on are offered: tangent to old elements, parallel to old elements and original model coordinate, the method of parallel to old elements is used in the construction stages analysis and the method of original model coordinate is used in the construction control analysis. The purpose of construction control analysis for pretensioned structure in this paper is that the architectural configuration should be satisfied after construction control analysis is finished. The procedure of construction control analysis for pretensioned structure is summarized. The computational accuracy and the effectiveness are proven by the example of the cantilever beam with cables.
Research of Strength of Dongji Reinforced Concrete T-Beam Bridge
Authors: Zhang Xiao Zhong , Liu Yong Bing , Hu Wei Xin , Zhu Jing Song
Published: May 2011

Based on the investigation and detection of Dongji Bridge, a reinforced concrete (RC) T-beam bridge, the major diseases of the bridge was identified. The disease characteristics and rules are classified, the strength of the bridge was analyzed by finite element technology. Research is expected to provide scientific and rational basis for maintenance and reinforcement of Dongji bridge and same style bridges, and lay a foundation for further research work for RC T-beam bridges.
The Transfer Matrix Method for Seismic Analysis of Curved Box Bridges under Multi-Support Excitation in Frequency Domain
Authors: Sun Jian Peng , Li Qing Ning
Published: May 2011

In this paper the transfer matrixes out plane of curved bridge are derivated.based on the FFT transform and the relationship between the quality and inertial force the point transfer matrix for vibration analysis is biult, and then establish the vibration transfer matrix and the total transfer matrix. Derivates the frequency domain transfer matrixes of single-span curved box bridges under uni-support or multi-support excitation, and offers a new method for seismic analysis of curved box bridges under multi-support excitation in frequency domain.
Study on Free Vibrations of Self-Anchored Suspension Bridges
Authors: Li Jie , Li Na
Published: May 2011

Study on characters of suspension bridges free vibration is basic to analyze wind resistance, shock resistance, and other dynamic behaviors. Current studies are usually focused on earth-anchored suspension bridges. Compared with earth-anchored suspension bridges, self-anchored suspension bridges are anchored on the girder end which makes girder under the compression condition, cable longitudinal displacement can not be neglected, in addition, large ratio of rise to span leads to cable large tilt angle. Based on functional analysis method, it uses variation calculus to derive differential equation of two-tower and three-span continuous self-anchored suspension bridges free vibrations, taking into account cable tilt angle and cable longitudinal displacement. According to the simplified differential equation, it draws to a formula that can calculate self-anchored longitudinal and vertical vibration frequencies. Finally, two examples are carried out to check the formula’s reasonableness.
The Large-Scale Direct Shear Test on Gravel Soil with Different Water Content in Badong of Three Gorges Reservoir Region
Authors: Wang Le Hua , Wang Jia Cheng , Li Jian Lin
Published: May 2011

The high cut slope of reservoir-bank road and city buildings are mostly earth-rock mixture after excavation. The strength behavior of the gravelly soil is important for mechanism of landslide triggering and soil erosion in Badong high cut slope. With the impact of rainfall, the water content of gravel soil increases, and the water table changes, this eventually affects the mechanical properties of gravel soils. Taking high cut slope which formed in the course of relocation in Three Gorges Reservoir as its background, the paper selected the gravel soil of typical high cut slope in Badong new town; and through on-site survey, analysis of geological conditions, indoor large-scale direct shear test, combined with laboratory test results, it discussed the influence of high cut slope gravel soil shear strength parameters by different water content of sample. At the end of this paper, it draws some beneficial conclusions.
Study on Mechanical Characteristics of Frost Heaving of Artificially Frozen Soil
Authors: Li Dong Wei , Xu Da Wei , Fan Ju Hong , Wang Ren He , Luo Bi Juan
Published: May 2011

The impact of the cold-side temperature and moisture to frost heave were obtained by studying frost heaving test in open system. Frost heave ratio increased linearly with the decrease of cold-side temperature and moisture. Frost heave force increased with the decrease of cold-side temperature and increase of moisture. In addition, the soil physical properties variation laws was gained during freezing in the test, like moisture and dry density. By analysising the test data of frost heave ratio and frost heave force, the relationship between frost heave ratio and frost heave force were acquired. The results had important practical value and theoretical significance to the freezing shaft sinking and artificially freezing techniques applied in urban underground engineering.
Study on Mechanical Behaviors of Underground Pipelines Due to Excavation of Foundation Pit
Authors: Yang Run Lin , Wang Juan Juan , Zhou Hai Cheng
Published: May 2011

It is necessary to study the mechanic behavior of underground pipelines during the excavation of the foundation pit, because the excavation will inevitably endanger the nearby underground pipelines. Three factors include the depth of underground pipelines, the distance from the pipeline to the foundation pit and ground load are considered to conform comparative analysis, in order to study the variaty on the stress and deformation of the underground pipelines. The foundation surporting type and the soil layer distribution are also considered during the numerical simulation. The results show that the distance between pipeline and foundation has more influence on the underground pipelines than other two factors, the damage most likely occurred in the bottom right in the pipeline near the foundation pit.
Complex Slope Stability Analysis of Slip Surface Stress Method Based on Nader Hypoplastic Model
Authors: Xiong Bao Lin , Tang Jin Song , Lu Chun Jiao
Published: May 2011

Hypoplaticity and Nader hypoplastic model are introduced. Based on finite element stress-strain analysis of Nader hypoplastic model, slip surface stress method in the slope stability is provided. The factor of safety of the slip surface is defined as the ratio of the critical shear intensity during failure to real shear stress and the critical slip surface of slope is ascertained with pattern search method. The clay slope with a weak foundation layer and clay slope with a foundation layer including a thin weak layer under the plane strain condition are analyzed. The results are shown that the shapes of critical slip surface and the magnitude of factor of safety are obtained by this method.
Analysis of Shallow Landslides Stability of Coal Measure Soil through Contact Elastic-Plastic FEM
Authors: Zhu Lei , Song Xin Jiang , Hong Bao Ning
Published: May 2011

In order to reveal the mechanism of deformation, disintegration and failure of shallow landslides of coal measure soil, through contact elastic-plastic FEM with shear strength reduction, the paper analyzes shallow landslides stability, calculates shallow landslides safety factors, and reveals the mechanism of deformation, disintegration and failure of shallow landslide of coal measure soil. The results are shown as follows: during shallow landslides of coal measure soil, the displacement of sliding mass sliding along sliding surface, the plastic strain of sliding mass and sliding mass sliding state along sliding surface don’t change simultaneously; adopting contact elastic-plastic FEM algorithm may better reflect the actual state and sliding process of shallow landslides of coal measure soil. It can help faithfully reflect real situations of shallow landslides like deformation, disintegration and failure of shallow landslide of coal measure soil, and it may afford one method that can be used as a reference of the stability analysis, accurate evaluation and forecast of this type of landslide.
Phenomena of Multicale Fracture of Brittle Materials and its Application to Teaching in Strength Theory
Authors: Wang Li , Rui Da Hu , Yang Jian Hui
Published: May 2011

Multi-scale science is the challenge and opportunity of science in the 21th century, and turbulence of liquid and fracture of solid will be the classical problems of multi-scale mechanics. The failure process of brittle materials displayed a multi-scale mechanics feature that amounts of micro damages grow large trans-scale and nonlinear and evolve to a macro catastrophic transition in the end. So, the concepts of scale and hierarchy of material are inescapable in strength theory to be used explaining solid fracture, it is the main puzzle of the strength theory at present. In the paper, in order to show the phenomena of multi-scale fracture, numeric method is used to simulate the failure process of brittle material, during which micro cracks initiate, grow large, aggregate and in the end form a run-through fracture band in the sample. The result of the numeric simulation shows that the micro cracks of a meso-scale size initiate due to tensile strain and the sample of a macro-scale size breaks down due to tensile-shearing strain under uniaxial tensile or due to compression-shearing strain under uniaxial compression. It powerfully disabused the puzzles in teaching strength theory of brittle material. The further discussion concluded that for a brittle material grain of meso-scale size, the theory of Maximum Tensile Strain is reasonable in explaining the strength, as for a brittle material sample of a macro-scale size, the mohr-columb theory is reasonable for its strength owing to the two important factors of cohesive strength and friction factorwere introduced.
Dynamic Buckling Equations and the Maximum Lower Limit Formula of an Elastic Column under Axial Loading
Authors: Xi Feng , Zhang Yu , Zhang Yun
Published: May 2011

Dynamic flexural buckling equations in large deflection for an elastic column with the effects of axial inertia and rotary inertia are derived via the principle of minimum acceleration for continua at finite deformation. The maximum lower limit formula for critical dynamic buckling load is obtained by eigenvalue analysis for rudimental buckling equation. It is found that the expression is same as the static Euler limit.
A Research of Reinforcing Ingate in Shale-Laminated Sandstone
Authors: Qiao Wei Guo , Lv Yan Xin , Wei Lie Chang
Published: May 2011

The auxiliary shaft ingate of Pengzhuang Coal Mine deformed greatly with large roof fallings. Through the analysis of destruction, the ingate reinforcement schema is put up according to the engineering consolidation experience and the advanced consolidation experience at home and abroad. On the completion of the ingate project, the surrounding rock mass is stable without apparent deformation. The two-side and roof deformations are 4mm and 5mm respectively according to the convergence deformation test, improving the integrity and bearing capacity of the shaft and pipelines effectively. Thus the deformation of the surrounding rock mass is under control, guaranteeing the long-term stability of the roadway.
Bearing Capacity of Suction Caisson Foundations Using FEM Analysis
Authors: Wang Zhi Yun , Luan Mao Tian , Shen Lu
Published: May 2011

To understand features of bearing capacity of suction caisson foundation is one of the key issues in design and construction of deep-water marine structures. In this paper, the general-purpose finite element analysis package ABAQUS is employed to conduct three-dimensional numerical analyses on load-carrying features of suction caisson foundation under vertically uplift load, horizontal load and moment. Then the ultimate bearing capacity of suction caisson foundation for undrained condition of the soil is evaluated by displacing-controlling procedure. Moreover, three-dimensional failure envelope of suction caisson foundation under combine loading condition are established by the proposed numerical procedure.
Stochastic Seepage Simulation for Bulk Terrestrial Domain Based on Difference Math Theorem
Authors: Ma Hui Biao
Published: May 2011

With Monte-Carlo theorem, inclusive of the uncertainty of double phase geo-material parameters as well as math model boundary condition, stochastic difference math model was carried out for bulk terrestrial underground water seepage on the basis of plain confined steady underground water flow math model. The key conclusions are: seepage field behavior has close relation with turbulence of random B.C.; distribution of stochastic head potential depends on the geo-born-variation of parameters and the methods introduced in this paper are applicable for this achievement.
The Bearing Capacity Character of Enlarged Base Shallow Foundation under Uplift Load
Authors: Lu Xian Long , Cui Qiang
Published: May 2011

By theory analysis and field tests, failure model of soil around foundation and ultimate uplift resistance of enlarged bass shallow foundation were analyzed. The results showed that the deformation and failure process of soil around foundation under uplift load undergone three phases: 1) soil upon enlarged base compressed, 2) appearance and extension of plastic zone of soil around foundation, and 3) soil around foundation general shear failure. With the combination of the Limit Equilibrium Method, and Sliding Curve Theory, a simplified theory model to calculate net ultimate uplift resistance of shallow foundation assuming cir failure surface under uplift load was established. Then three examples were calculated by this method and the good agreement between theory calculation solution and experimental results validated the rationality of the model. The study in this paper provided an important theoretical support and brand-new idea on calculation method of uplift capacity of foundation with enlarged base and failure surface characteristics determination of soil around foundation.
Elasto-Plastic Numerical Analysis on Elliptic Cavity Expansion under Uniform Pressure
Authors: Liang Heng Chang , Zhou Guo Qing , Shang Xiang Yu
Published: May 2011

Analysis of the expansion of cylindrical and spherical cavities in soil and rock provides a versatile and accurate geomechanics approach for study of important problems in geotechnical engineering. As the method getting more important, the analysis of non-circular shape cavity is becoming significance. The paper has investigated the cavity wall shape varying characteristic and elasto-plastic distribution of stress of elliptic shape cavity under internal uniform pressure during the expansion period through ABAQUS FEM numerical. It pointed that the elliptic cavity wall will tend to circle shape as the internal uniform pressure increasing. It also gain that the elasto-plastic distribution around the elliptic cavity is bigger than spherical cavity’s and smaller than spherical cavity’s when material and pressure are same . The stress characters and the cavity wall transfiguration result is useful for estimate non-circular shape cavity expansion.
The Numerical Simulation of Bearing Capacity of Pile-Bucket Foundation under Combined Loading of Up-Pull and Horizontal Force
Authors: Liu Wen Bai , Zhao Long , Jia Ning
Published: May 2011

By using ABAQUS software to conduct numerical simulation and model test of pile-bucket under mono-loading of up-pulling force and horizontal force, then make comparison of both results to testify the accuracy of finite calculation model. Then by numerical simulation to study bearing capacity of pile-bucket foundation under combined loading of up-pull and horizontal force. The result shows the pile-bucket foundation horizontal displacement will increase with the increase of up-pulling force at the limit horizontal load, and the horizontal displacement becomes more obvious as the up-pulling load increasing if providing greater horizontal loading force. Before the up-pulling force reaches the limit, horizontal load will not affect up-pulling displacement; after the up-pulling force reaches the limit, the horizontal load can slightly reduce the up-pulling displacement of pile top. The effect of up-pulling load increase on horizontal displacement is obvious for pile depth in soil at 0~15m, but very tiny for pile body with buried depth over 15m.
Experimental and Theoretical Study on Mechanical Properties of Concrete under Triaxial Compression after Suffering High Temperature
Authors: Yao Jia Wei , Song Yu Pu , Gao Ling Xia
Published: May 2011

Little progress has been made in experimental studying on high-temperature mechanical properties of concrete under multiaxial compression. Triaxial proportional compressive tests of ordinary concrete after suffering to high temperature (200°C ~600°C) were carried out, the designed stress ratios are 0.1:0.25:1, 0.1:0.5:1, 0.1:0.75:1 and 0.1:1:1. The failure models of concrete specimens after suffering high temperature were observed. The biaxial compressive strength and deformation characteristics of which were measured. The influences of temperature and stress ratio were analyzed. On the basis of the analysis, the relationship between compressive strength and temperature as well as stress ratio was established in octahedral stress space.
Research and Development of one Kind of Acousto-Elastic Sensitive Concrete Material
Authors: Lin Jun Zhi , Zhao Ming Jie , Wu De Lun , Yang Hong Wu , Liu Xin Jian
Published: May 2011

A tentative experiment has been conducted on polymer modified cement concrete now widely used. By filtering through 297 kinds of traces of polymer modified cement concrete samples tentatively mixed, we acquire a proper mix proportion, according to which, a total of 75 groups of 225 polymer modified cement concrete specimens are produced. After further selective preference of these specimens, ultrasonic test is done on the selected ones under different loading conditions. Afterwards, signal processing is accomplished by using wavelet transformation and we preliminarily find a kind of acousto-elastic sensitive concrete material which is comparatively sensitive to stress. This kind of material is produced by mixing epoxy resin, styrene-acrylic emulsion, acrylic emulsion, auxiliaries and iron powder into cement concrete together. The sensitivity of ultrasound and stress of this kind of modified concrete behaves preferably well as follows: at the low stress stage, not only the correlativity curve of ultrasound velocity and stress but also the correlativity curve of weighted spectrum area and stress arises apparently. If this kind of material can be applied to the practical engineering successfully, the acousto-elastic test accuracy of the concrete service stress will be greatly improved.
Unloading Characteristics of Hard Rock at Depth
Authors: Lv Ying Hui , Feng Xia Ting , Liu Jun Yan
Published: May 2011

DaGangShan power station in China is being excavation at 1500 meters deep below earth surface, where the surrounding rock is affected by high initial geo-stress. Deep excavation of rock tunnels causes release of high initial geo-stress and produces unloading action. As thus, a series of representative unloading tests on hard granite from DaGangShan power station are carried out to simulate dynamically excavation process, and in unloading tests, the stress path of decreasing confining pressure along with increasing axial pressure is accepted. The results of tests show as follows: (1) Under unloading condition, lateral deformation occurs in the unloading direction and volumetric strain changes from compression deformation to dilation deformation. (2) Under unloading condition, crack deformation appears, which results in Poisson’s ration rise and deformation modulus decrease. (3) Under unloading condition, hard granites behave brittle failure and Mogi-coulomb criterion can well describe the failure characteristics.
The Study on Performance of Single-Layer Cylinder Shells with Semi-Rigid Bolt-Ball Joints
Authors: Wen Ming , Wang Xin Fang , Deng Zi Chen
Published: May 2011

A bolt-ball is a commonly joint form in latticed shells. It’s a typical semi-rigid joint, which can bear certain amount of bending moment. The performance of triangle mesh single-layer cylinder shells with bolt-ball joints in different support conditions has been analyzed detailed using the finite element (FE) software ANSYS based on several different parameters including bending stiffness, torsional stiffness, shell span, ratio of rise to span, ratio of length to width and load distribution in this paper, and key influence parameters to the load carrying capacity of cylinder shells with semi-rigid joints in different support conditions are obtained. Finally, based on the results obtained by FE calculation, a new formula is proposed for getting ultimate load of single cylinder shells with semi-rigid joints in four sides support, some references are provided for shell design.
Analysis on Variable Bond Strength Failure Criterion of Layered Rock Mass Based on Numerical Simulation and Model-Test
Authors: Xia Bin Wei , Wang Jie , Lu Yi Yu , Kang Yong , Li Dong
Published: May 2011

The layered rock mass consists of kinds of stratifications whose mechanical properties are not wholly identical with each other. In order to figure out its strength failure criterion, the variable bond strength failure criterion is proposed depending on Mohr-Coulomb yield criterion and the change law of the strength parameters varying with the dip angle of stratification plane (that is the angle between the maximum principal stress and the stratification plane). What’s more, the criterion is verified by physical model test and numerical simulation adopting assembly language VC++6.0. Compared with the results of physical model tests and numerical simulation, it is shown that the stress distributions and failure regions are elliptic in shape and that the maximum failure regions are vertical to the stratification planes. That the results obtained in the physical model test are compatible with those numerically obtained verifies the correctness of variable bond strength failure criterion.
The Time History of Axial Force of Soil Nail in Deep Excavation Course
Authors: Li Feng , Guo Yuan Cheng , Shi Gang , Qian Hui
Published: May 2011

This paper presents a theoretically study on the time-dependent characteristic of soil-nail axial force in the whole construction process of foundation pit. Firstly, the time-varying performance of axial forces of soil nails is analyzed according to the measured lateral deformation curves of pile-anchor and soil-nail composite supporting deep foundation pit. Then combined with a soil rheological model, a time-dependent formula of soil nail axial force is put forward, and the simulated results are compared to the back-analyzed ones. Finally, a formula to predict the time-dependent axial force of soil nail in the whole construction process of foundation pit is established and an example is investigated to validate the method.
Study on Stressed Characteristic of Gridding Concrete Retaining Wall Used in Excavation of Soft-Soil Foundation Pit
Authors: Zhou Guang Zhu , Wei Xu , Yu Chen
Published: May 2011

As a new type of building envelope, Gcrw is mainly used for excavation of foundation pit. It can stand by itself without the help of bracing, especially in soft soil area. Its stressed characteristic hasn’t been known yet. By using advanced big finite element software Abaqus/Cae, a simulation was made on model of Gcrw under soil pressure when a foundation pit is dug, while the whole excavation is divided into three continuous independent excavation stages. The result shows that Gcrw is a rather good building envelope, Gcrw and soil in the gridding form an integral earth-retaining structure and keep balance under soil pressure before or behind the structure, and have little displacement in horizontal direction. It is like a gravity-type retaining wall in its entirety, but takes on an elastic characteristic. The soil pressure presents a linear change, but its value is less than the theoretical value of calculation. The front wall of Gcrw, like a sheet, is the main flexural construction element, which is subjected to the pressure from side wall of foundation pit and produce curve deformation. The back wall of Gcrw has little displacement and almost is built in the clay. The partition wall endures the effect of the tensile force, its horizontal deformation increases with the build-in depth’s increasing. The back wall and the partition wall play a very important role in dragging back the front wall, the role of them is similar to a pair of anchor tie. The soil in the gridding not only provides soil pressure, but also can fix the back wall, so it is seen as a part of Gcrw and in favor of the Gcrw’s anti-overturn.
A Simple Constitutive Model for Overconsolidated Clays
Authors: Liu Yang , Zhu Xian De , Gong Zhi
Published: May 2011

In the framework of critical state soil mechanics, a simple constitutive model for overconsolidated clays is proposed based on subloading surface and normal consolidation yield surface. A more rational hardening law is used to describe the change between subloading surface and the normal consolidation surface with plastic deformation and an associated flow rule is adopted. The model can describe many characteristics of overcaonsolidated clays, such as stress-strain relationship, strain hardening and softening, and stress dilatancy. Compared with the Cam-clay model, two more parameters are required which represents specific physical meanings. Numerical simulation is compared with data from triaxial drained compression test, indicating that the proposed model can rationally describe overconsolidated properties.
Least Square Inversed Analysis of Soil Parameter for Foundation with Two-Order Gradient Theoretic Method
Authors: Xie Yao Feng
Published: May 2011

Combined with two-order gradient theory, the least square inversed analysis of the soil parameter for the foundation is studied and put forward in detail. After the mechanical theory for the plate on the foundation is introduced, the controlling differential equations of the plate on the foundation which is subjected to vertical loads are deduced. Through utilizing Fourier transformative theory, the corresponding solutions to the plate on the foundation are gained. Linear algebra controlling equations for the plate are achieved which leads to solve the original differential equations more easily. The least square error function for the soil parameter on the plate is established and applied with the two-order gradient method. The inversed steps on the least square error function for the soil parameter are listed. The calculation results verify the conclusions that the soil parameter of the foundation can be efficiently inversed by applying the least square theory. When different initial soil parameter is set, the iterative computations can be convergent to the true value of the soil parameter. And this least square method can also be applied for the problem of inversed analysis of parameters for other foundation models.
Research on Deformation Law of Deep Excavation Supporting Structures in Beijing Metro Station
Authors: Li Qing Yuan , Wang Yang
Published: May 2011

Taking deep excavation engineering in North Region of Senlin Park Station of Beijing Olympic Subway branch as engineering background, deformation law of enclosure structure of deep excavation are studied by the in-situ monitoring means .It shows that the maximum horizontal displacement of retaining pile is closely related with excavation depth and time. When the deep foundation pit is excavated to a certain depth, and steel brace hasn’t been erected, horizontal displacement of the pile tops is maximum. The location of the maximum horizontal displacement shifts down with foundation pit excavation and steel brace erection. With steel brace application, steel axis force decrease, so steel brace can effectively control horizontal displacements of retaining pile and internal force of steel in the pile. In addition, temperature has a certain effect to axis force of steel brace.
The Research on Optimal Design of the Whole Process of the Piles′ Diagonal Brace System Base on Coordinating Space Role
Authors: Liu Jun Yan , Liu Yan , Hou Yue Zhen , Jin Bai Xi
Published: May 2011

Compare with horizontal support, the bracing systems of pile and oblique brace have obvious advantages in deep excavation. However, because diagonal brace is inconvenient for the construction of structure , the use of this system is limited. Based on the coordinating space role of this support system, planning the excavation and exchanging brace and construction structure as a whole, according to the minimum potential result of a piecewise space unit, this paper introduces the model which are both applied to the excavation stage and exchanging brace stage, and derives the calculation method in relationship to the length of sub region. optimal design of the whole process was proposed for this form. Finally, the feasibility and rationality of the proposed method was verified by the practical engineering. And reached some signifecative conclusions, these can provide reference for the design and construction of such supporting system.
Experimental Studies on Wind Erosion Mechanism of Aeolian Soils Subgrade Slope for Desert Highway
Authors: Li Chi , Gao Yu
Published: May 2011

Wind erosion mechanism is studied through interior wind erosion wind tunnel experiment for desert highway. The anti-wind erosion ability of Aeolian soil subgrade slope is equivalent to the variation of microstructure characteristics and shearing strength of Aeolian soil. Microstructure characteristics will be quantified analysis through scanning electron microscope and image analysis software for subgrade slope, and microstructure parameters are picked-up for wind erosion fore-and-aft. Aeolian soil’s Shearing strength and wind erosion depth are investigated at different position of windward slope during a long-time wind-blown. Then, wind erosion mechanism of Aeolian soils subgrade slope is clarified from two aspects of micro and macro, wind erosion influence depth is determined for certain environmental condition. Taking desert highway subgrade as an example, the results indicate that: the disturbance to the flow field enhances with the increase of slope ratio and subgrade height, wind erosion of the windward slope is severe. The anti-wind erosion ability on windward slope is weak obvious with the decreasing of soil’s water containing, the increasing of wind velocity and the blow time prolong. Shearing strength of Aeorian soil is gradually decreased from slope surface to its interior, from bottom to top of windward slope. According to environmental condition local, when average wind velocity is 11m/s and natural water containing is 2%, wind erosion depth is about 15mm on the top of slope which is 1/11 of subgrade height, relative to 10mm on the mid of slope. The conclusions drawn from micro and macro are proved the wind erosion mechanism of Aeolian soils subgrade slope perfectly.
Numerical Simulation on the Reinforcing Effect of New CFG Pile-Board Structure Composite Foundation
Authors: Zhang Ding Bang
Published: May 2011

The new CFG pile-board structure composite foundation is a ground treatment technique based on CFG pile foundation and pile-board structure composite foundation. It can make full use of the load distributing function of board, the bearing capacity and the deformation compatibility of soil between piles, by taking advantage of the pile-platform-soil interaction. A part of soft ground in a high-speed railway was taken as the engineering background and study object. The settlement controlling effect of common CFG pile ground and new CFG pile-board structure composite foundation were analyzed by finite element numerical method, and various factors to the effect on settlement-controlling were discussed. Pile-soil stress ratio of CFG pile and reinforced concrete pile were studied. Some useful conclusions of the numerical simulation of the new CFG pile-board structure composite foundation were obtained.
Optimization Strategy of the Long-Short-Pile Composite Foundation Based on the Settlement Control
Authors: Guo Yuan Cheng , Zhang Si Hua , Shi Gang , Liu Ning
Published: May 2011

By using finite difference software FLAC3D, the displacement field and stress field of the long-short-pile composite foundation were studied, as well as the distribution of axial force, neutral position and penetration amount. The effects of the main parameters of long-short-pile composite foundation on its working properties, such as the modulus and thickness of the cushion, the length and quantity of the long pile, are investigated in detail. The results show that the modulus and thickness of cushion have less effect on the foundation settlement, while they can affect the pile-soil stress ratio significantly. Moreover, increasing the number of piles can control the foundation settlement effectively. The stresses in upper soil layer can be transferred to lower soil layer effectively, with the increasing of the number of long piles. Then the foundation settlement can be reduced correspondingly. While the variation of the number of piles has less effect on the stress field when the number of piles reaches a certain extend, and the reduction of the foundation settlement tends to slow down. Further, the foundation settlement decreases with the increasing of long-pile length. Finally, based on the foundation settlement control, the recommended values of parameters are given.
Field Test of DX Pile Group
Authors: Tang Song Tao , Chen Li Hong
Published: May 2011

DX pile is a newly developed variable cross-section pile. Compared to conventional straight pile, it has distinct advantages on bearing capacity and settlement control. However, the bearing mechanism and characteristics of settlement, especially on group DX piles, are not clear. This paper illustrated and analyzed the bearing capacity and settlement characteristics of single DX pile and group DX piles according to the test results of in-situ model test. Special attention was paid on single and group DX pile comparison under same circumstances, at the mean while, compared the single DX pile and conventional pile with the same pile length and diameter, and with the same bearing capacity. The conclusions from the test results provided theoretical references for the design of the DX piles in engineering practices.
Influences of Deviatoric Stress on the Soil-Water Characteristic Curve
Authors: Fang Xiang Wei , Jiang Shu Ping , Shen Chun Ni , Xie Yun , Li Gang
Published: May 2011

The soil-water characteristic curve (SWCC) is one of the major research subjects in unsaturated soil mechanics. To study the influence of deviatoric stress on the SWCC of an unsaturated soil, a series of triaxial drained shear tests by controlling constant net mean stress and suction were conducted. It was found that the SWCC was dependent on deviatoric stress. A unified SWCC equation was proposed including not only water content and suction, but also net mean stress and deviatoric stress.
Evolution of Meso-Structure of Intact Loess during Loading
Authors: Shen Chun Ni , Fang Xiang Wei , Wang He Wen , Xie Yun , Li Gang
Published: May 2011

A series of triaxial shear tests on unsaturated intact loess were conducted using CT-multi-function triaxial apparatus. The distinct CT images and relevant CT data were obtained nondestructively during triaxial shear. CT data was used to define a structure parameter and an evolution variable which characterized the evolution of meso-structure. An equation is proposed to describe the evolution of meso-structure of unsaturated intact loess during loading, which reflects the influences of net cell pressure and suction on the evolution of meso-structure.
Simulation Test on the Cement's Stiffness-Contribution of Reinforced Cement Mixing Wall
Authors: Chen Wen Zhao , Gao Quan Chen , Jiang Jun She
Published: May 2011

Based on the model test,ABAQUS, the large-scale nonlinear finite element software was applied to build the numerical simulation model of the reinforced cement mixing wall in soft soil. The model parameters were obtained and the model was optimized with the technique of parameter inversion. Based on equivalent principle, the equivalent model was built to study the Cement'sStiffness-Contributionin reinforced cement mixing wall and its equivalent Stiffness was obtained. Analysis shows that the presence of cement can increase the core pile stiffness by 13.2%.
Analysis of Loss Influence on Key Members of Frame Structures Subjected to Blast Loading
Authors: Yang Run Lin , Zhang Shun , Bi Lu Bo
Published: May 2011

With increase of terrorist blast, it is becoming more important for buildings to resist the blast load than before. This paper focuses on analysis of loss influence on key members of frame structures subjected to blast loading. The performance of a 5 storey frame structure with damage was evaluated on the assumption that whose key columns and beams had been lost after blast. By comparing the deformation and the internal force of the original frame with the corresponding items of the incomplete one, the impact of the key columns or beams on the performances of the whole frame structure was discussed. Numerical results show that the loss of either the key columns or the key beams will endanger the whole structure. Especially, the deformation and the internal force of the members adjacent to the missing key column have obvious increases. Consequently, the loss of the key column exerts a more serious impact on the building than that of the key beam.
Stability Assessment of Silin Powerhouse Cavern Based on Displacement Back Analysis Method
Authors: Yang Yun Hao , Shi Chong , Zhang Ling Ran
Published: May 2011

A back analysis procedure synthetically using parameters sensitivity analysis based on orthogonal design variance analysis, support vector regression modeling of nonlinear relation between mechanical parameters and displacement, and a hybrid optimization algorithm of particle swarm optimizer (PSO) and differential evolution (DE), was proposed. Optimum values of elasto-plastic mechanic parameters of rock mass were identified using the back analysis procedure and the measured displacement data. Assigning to the numerical model the optimum values of parameters, numerical simulation of powerhouse construction process was carried out to investigate the reliability of result of back analysis and the stability of powerhouse cavern. The result shows that calculated displacements are in good agreement with the measured, the powerhouse cavern is stable and has a considerable safety margin, and the existing support system can satisfy the need of local stability of powerhouse.
Research on the Method of Determining M Value of the Rock-Socketed Continuous Wall
Authors: Zhang Hai Yan
Published: May 2011

In recent years the rock-socketed continuous concrete walls have been applied in supporting structure of foundation excavation, and the main problem of which is how to simulate m value of wall bottom bedrock. In this paper, the m value of rock-socketed underground continuous concrete wall bedrock is monitored by a structural test about a typical engineering. The monitored data of foundation excavation supporting deformation are fitted by least-square method, and the bedrock m value of which are researched and analyzed based on an optimization method and fitting deformation curves. The test shows the monitored m value meets the corresponding engineering regulations and is related with the broken degree of rock on the monitored position, and the variability of which is lesser in the construction process.
Application of Flac2D to the Temperature Calculation and Approximate Damage Analysis for the Canister Retrieval Test in Sweden
Authors: Luo Si Hai , Christiansson Rolf
Published: May 2011

During the period from October 2000 to November 2005, the canister in the CRT deposition hole DD0092G01 was heated with a maximum heat power of 2600W and the temperature and consequently the stress in the surrounding rock volume were elevated. This study investigated if the temperature and possible heat induced damage can be predicted by 2-Dimensional numerical simulations. FLAC2D(5.00) was used to model the excavation and the heating process of the deposition hole. Temperature in the rock was calculated by treating the case either as a horizontal two dimensional or a vertical axisymmetric problem and obtained results were compared with the measured results, whereas stress was calculated from horizontal two dimensional thermal-mechanical coupling analysis and calculated results were applied to approximate damage analysis.
Numerical Simulation Methods and Parameters of Geo-Grid Rein-Forced Retain Fly Ash Wall
Authors: Shi Wei , Chen Xiao Wen , Liu Ji Ming
Published: May 2011

Deformation of the geo-grid rein-forced retain fly ash wall and the reinforcing effect of geogrid reinforcement, depends largely on the role of interface properties between the geogrid and fly ash. Interface in the numerical simulation of the mechanical properties of the main elements reflected in the geogrid on the constitutive parameters,for example, shear stiffness,Cohesion,Modulus, reinforcement length and so on. In this paper, geogrid reinforced fly tangential stiffness, cohesion, elastic modulus, reinforcement length and other parameters on geogrid reinforced retaining wall deformation characteristics of fly ash for numerical simulation and comparative analysis,Obtained parameters on geogrid reinforced retaining wall mechanical behavior of fly ash, stability and reinforced the effect of law, Provide theoretical and analytical basis for the geogrid reinforced and reinforced fly ash characteristics of the interface wall wide application in engineering.
Influence of Blasting Vibration on Roadway Loose Range
Authors: Shao Xiao Ning , Xu Ying , Wang Hai Bo
Published: May 2011

Roadway loose scope nearby the excavation section was tested by sound wave loosing zone testing instrument. According to the analysis: the shorter distance to the excavation section, the more influence by blasting vibration; the influence is decreased along with the distance increased, and finally to stabilize. Meanwhile, numerical simulation on effective stress of rock nearby blasting section was did with ANSYS/LS-DYNA, got the same conclusion as testing. The research result can provided a basis for reasonable selection of blasting parameters, reduce blasting vibration effect.
The Analysis on Monitoring Data and Finite Element Simulation of the Deep Foundation Pit in Tianjin
Authors: Feng Shi Lun , Han Yong , Li Jun , Li Pu Lin , Liu Jie
Published: May 2011

Through the analysis on monitoring data of the deep foundation pit in Tianjin, it was observed that the lateral deformation of the retaining wall at the corner was smaller than the deformation in the middle. Based on the analysis of the results drawn from finite element simulation of the excavation process and the monitoring data, appropriate supporting structure stiffness parameters values used in Plaxis and Qimingxing are recommended for designing deep foundation pits in soft soil area.
The Resilience Deformation Rules Test Research of the Soft Soil in the Unloading Condition
Authors: Tang Bin , Wang Ren , Lei Jun
Published: May 2011

The resilience deformation rules laboratory test research of the soft soil in the Wuhan region in the unloading condition is done through modified triaxial compression apparatus .And the result shows:(1)the critical unloading ratios of the soft soil in Wuhan region is 0.28 and 0.91.No matter the unloading amount is, no resilience deformation is produced when the unloading ratio is smaller than 0.28 or larger than 0.91,and the resilience deformation is produced when the unloading ration is between 0.28 and 0.91.(2)The void ratio is related to the initial preloading ,the bigger the preloading, the smaller the void ratio, and the bigger the increasing of the void ratio after unloading; the smaller the initial preloading ,the bigger the void ratio, and the smaller the increasing of the void ratio after unloading.(3)The peak resilience rate is linear to the initial preloading.
Research on Punched Pile Construction–Induced Dynamic Response of Bridge Pile Foundation
Authors: She Yan Hua , Su Hua You , Xiao Zheng Xue
Published: May 2011

By use of the microseismic monitoring system, the dynamic response of punched pile construction of bridge pile foundation is studied and discussed for the first time. Wave data of loads acting on the construction is group-collected by means of the microseismic experiment on site. Then the waveform, vibration frequency and energy of testing data are analyzed. On the basis of the results, the weaken rules of vibration acceleration and energy are studied, and the effect of impact energy on the vibration velocity is analyzed. It shows that impact energy attenuates exponentially with the distance from the epicentre. The conclusion establishes the theoretical basis for studying the vibrant characteristic of punched pile construction, and provides valuable reference for engineering practice to take effective measures to reduce construction vibration.