bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Tensile-Shear Failure of Fractured Rock Mass under Strong Seismic Load
Authors: Lu Guo Sheng , Wang Xun , Chen Xiao Lan
Published: May 2011

Fractured rock mass endures tensile-shear and pressure-shear effects under horizontal seismic force. Based on rock fracture mechanics and the maximum circumferential stress theory, the extending condition (that is, the critical acceleration), the extending direction and the crack extension length under different direction of horizontal seismic force have been studied. The results are useful for judging the risk of dangerous rocks and providing a theoretical basis of pre-identification in the earthquake zone.
Research on Sliding Cable with a Nonlinear Analysis Method for a Cable-Membrane Structure
Authors: Liu Kai , Wang Xin Yi
Published: May 2011

Cable sliding in membrane pockets or on membrane surfaces has not yet been considered in analysis of cable-membrane structure software. In this study, a new sliding cable element has been created, using the non-linear finite method and a model of line-elastic and non-linear sliding stiffness. First, this paper outlines existing computational methods for creating sliding cables and questions the accuracy of these current numerical models. Second, it determines the sliding stiffness of sliding cables by examining the relationship between the original length and the end tension of space two-node linear cable elements. Third, the solution arithmetic for cables sliding in membrane pockets or on membrane surfaces is proposed with consideration of correctional linear sliding stiffness. Finally, the method developed herein is validated by one example.
Numerical Analysis for Displacement Law of Deep Alluvium Frozen Wall in Thousand Metres Vertical Well
Authors: Wang Jun , Ji Hong Guang , Wang Chuan Qing , Luan Kaiyun
Published: May 2011

During freezing sinking, the displacement and affecting factors of deep alluvium frozen soil wall was a technical problem which need to be resolved. Based on designing frozen soil wall in deep alluvium in thousand metre vertical wall, making use of mathematic simulation software of FLAC after selected ten samples from exceeding 400metres depth as calculation model, which the frozen clay creep parameters with finite transformation considered, the maximum radial displacement was obtained. The factors affecting it such as frozen soil thick, height of deep alluvium, segment height, exposure time and excavated radius were utilized. The mathematic formula was acquired with regression analysis through fifty datas, and detected with in-situ measurement data. The result of two types coincids, which indicates it can provide conducting in designing frozen soil wall under similar geoloical projects.
Study on Mechanical Property and Strength Formation Mechanism of Red-Mud and Fly-Ash Aerated Concrete
Authors: Wang Rui Yan , Zhang Lan Fang
Published: May 2011

Red mud is the waste which is generated in the process of extracting alumina from bauxite. In this paper, results showed that aerated concrete preparated with red mud, fly ash and other solid industrial waste, its strength can reach 2.5 ~ 5.5MPa, density of 550 ~ 800kg/m3, radioactive limit meet the requirement of material to the wall. Use of red mud to produce aerated concrete is an effective way with good environmental and economic significance.
Research and Use of the Steel Sheet Pile Supporting Structure in the Yellow River Delta
Authors: Yan Qing Zhi , Rao Jiang , Xie Zi Qiang
Published: May 2011

The excavation and support problem of deep foundation pit is very interested by construction engineers with the development of the high buildings in cities and exploration utilization of the underground pace. Stability and economy are the most important problems in deep foundation pit support. This paper mainly studied on stability and economy of steel sheet pile support structure. The steel sheet pile support technique was fully introduced and analyzed here, using a combined method of theoretical guidance, calculation analysis, engineering application with finite element program simulation and market investigation.
Triaxial Creep Experiment of Red Sandstone
Authors: Cao Ling , Wang Zhi Jian , Xu Yong Fu
Published: May 2011

Creep is an important mechanical property of rock, and it is closely associated with the long-term stability of rock landslides. To further discover the sliding mechanism of the horizontal-strata landslides, red sandstone samples were taken from Erchengyan horizontal-strata landslide bedrock in Wanzhou, and triaxial creep tests by step loading technique were conducted on red sandstone with RLM-2000 triaxial rheology test machine. The triaxial creep tests lasted 1180h under the constant temperature of 18.5±0.5. Boltzmann superposition was adopted for test data processing, and an improved translational coordinate method was used to reduce the degree of the data distortion. With the improved method, a complete creep curve of red sandstone strikingly consisted of three stages, namely, attenuated creep stage, steady creep stage and accelerated creep stage. The complete creep curve of red sandstone can be fitted by Burgers model.
Behavior of Soil Nailing Protection with High and Steep Bedding Stone Cutting
Authors: Ding Jun Xia , Yang Guang Qing , Xiong Bao Lin , Zhou Qiao Yong
Published: May 2011

This study is expected to research the performance, behaviors and strength of soil nailing by field test, based on the engineering of soil nailing wall protection with the high and steep bedding stone cutting in Chong Qing - Huai Hua Railway in China. We test the nail force of different station on different row soil nailing with vibrating reinforcing meter. Some conclusion elicited such as the rule of nail force with nail length and time, the potential sliding surface and the rule of soil nailing wall earth pressure with the height of wall. The test results can be used as reference for the design and construction of soil nailing wall.
Effect of Particle Size to Sand’s Shear Strength and Deformation under High Pressure
Authors: Lu Yong , Zhou Guo Qing , Shang Xiang Yu , Li Yong Song
Published: May 2011

This For mastering the effect of particle size to strength and deformation characteristics of sand under high pressure, DRS-1 high pressure direct shear test system is used in shear test for 3 groups of sand under pressure of 12 to 15 MPa. Through analysis of the test results, it is obtained that standard sand under high pressure shows strain hardening and volume contraction characteristics. The relationship curves of stress-strain and volume contraction-shear strain appear as hyperbola, they can be simulated by Duncan-Chang hyperbolic model. Sand with small particle size has better group, greater density and higher strength, but the shear contraction is not obvious. Sand with poor group has particle crushing under high pressure, which makes the soil particles rearrange and then the average porosity decreases at the same time large pores disappear, so finally it shows a more significant shear contraction characteristic.
Research of Mechanical Property on High-Rise Building Shear Wall-Influence of Border Concealed Column Toward Shear Wall Stiffness
Authors: Zhao Xin Hui , Li Jin
Published: May 2011

This article is probed into on the issue that the influence of border concealed column toward shear wall stiffness. Charge example indicates finite element that this text set up calculate model is acceptable. It is used the finite element method basic theory to compile finite element analysis procedure with four points rectangles unit to solve this problem. It can calculate the shear wall with concealed column’s displacement under the wind load to check the result it whether can be satisfied the design request. Using this procedure, this article carries on the finite element modeling analysis on a ten-floor building shear wall structure system. The procedure’s result and the software of ANSYS’s result tallies well, and it also be compared with the simplification computation’s result.
Further Study on the Application of Self-Boring Pressuremeter Test in Clays
Authors: Cao Quan , Chen Hong
Published: May 2011

The self-boring pressuremeter test has potential advantages over the conventional in situ method in the geotechnical investigation. It not only provides fundamental soil properties for the designer, but also plays more important role in the geotechnical analysis. With help of Cambridge self-boring model pressuremeter tests, some new application are studied in this paper as following: (1) Analysis of stress paths in clays adjacent to the cavity wall during self-boring pressuremeter test; (2) Experimental investigation on stiffness of soils at small strain under non-linear analysis; and (3) Study on magnitude of the changes in pore-water pressure of clays, which will help to enlarge the application of self-boring pressuremeter test in geotechnical engineering.
Treatment of Weak Foundation Based on the Cast-in-Place Expanded Pile of Construction Waste
Authors: Liu Hua Qiang , Fan Xiao Yi
Published: May 2011

There were better economic and social benefits which the construction wastes were the raw materials of weak foundation treatment. The cast-in-place expanded piles of construction waste showed the advantages of the dynamic replacement and compaction replacement. In the paper, the mechanism, design, construction technology and inspection of weak foundation treatment were studied. The result showed that the cast-in-place expanded piles of construction waste not only could save the cost in the waste transportation, but also decrease the cost in the foundation reinforcement and avoid the land contamination.
Theory Analysis of Temporal Correlation of Filling Body’s Stability
Authors: Fu Bao Jie , Gao Ming Zhong , Tu Min
Published: May 2011

On the basis of establishing mechanics model, viscoplasticity theory and principle of minimum potential energy , temporal correlation of the filling body was analyze . The necessary conditions of the filling body’s stability and the formula of minimum steady time were obtained. Theory analysis shows that the filling body’s steady time decreases with the increase of plastic area; when elastic modulus, hardening parameter and coefficient of viscosity are exogenously decided. The filling body’s steady time decreases with the increase of elastic modulus, and increases with the coefficient of viscosity. Gradual failure theory indicates that plastic range of filling body has a close relationship with in-situ rock stress, it provides theoretical basis for parameter selection and design of the gob-side entry retaining.
Active Earth Pressure on Retaining Walls with Layered Cohesive Backfills and Considering Cracking
Authors: Jiang Xi Yan , Di Su Wei
Published: May 2011

Based on the method of level-layer analysis, with the sliding harmonious condition of layered backfills considered , the theoretical answers to the unit earth pressures , the resultant earth pressures and the points of application of the resultant earth pressures on retaining walls with layered cohesive backfills are set up . The comparisons are made with Rankine’s formula.
Unloading Triaxial Experimental Study on Stress Path of Excavated Soil Slope
Authors: Zhang Yan Gang , Zhang Kun Yong , Li Wang Lin , Shi Qiao Zhen
Published: May 2011

The current research was implemented to study the practical unloading stress path that the slope mass experienced during the excavation process, which is very important in the stress and strain numerical analysis. Series of unloading tests were carried out under different confining pressure. During the test process, the minor principal stress was kept decreasing, while the major principal stress was kept unchanged to simulate the stress path in some locations of the soil slope, such as at the top of the slope. The corresponding conventional triaxial compression tests were also carried out as comparison. It is shown that there are many differences between the unloading and loading tests. Through analyzing, the tests results could be applied in the development of unloading constitutive models of excavation soil mass. Also, such unloading tests data are valuable in calibration and verification of the current existing popularly used models.
Settlement Analysis of Municipal Solid Waste Landfill
Authors: Liu Xiao Li , Wang Yu Jie , Zhu Chun Ying
Published: May 2011

In conventional soil mechanics method, the soil particle is known as rigid and its size remains unchanged during a compression. With regard to waste landfill, however, the degradation can decrease the volume of solid particle, produce new gases and liquids. Settlement character, excessive settlement and differential settlement of waste landfill might lead to all kinds of pipelines rupture, and then percolate cannot be expelled and result in rising ground water level. This will threaten seriously the stability of the landfill. It is fundamental to the landfill recycle to calculate the stability of settlement after closure of landfill. Based on the landfill site engineering in Langfang of North China, this article explores a new computing method of the landfill settlement with layering filling and organic matter degradation. Different factors influences on settlement are analyzed by the computer numerical simulation to offer evidence to the landfill recycle.
Properties of Foam and Soil Improvements for Earth-Pressure Balance Shield Construction in Red Soils
Authors: Li Tao , Liu Bo , Li Yan , Song Chang Jun
Published: May 2011

Soil improvement by foam is a key technique to control formation damage in shield construction. The half-life of three kinds foam was obtained by test self-developed foam and other two types. Meanwhile, their characteristics of stability and dissipation were analyzed. The physical-mechanical characteristic of red clay which was improved by foam was tested. Test result show that as the foam concentration increasing, the cohesion and plastic fluidity of soil increases firstly and then decreases, but the internal fiction angle decrease always. The permeability of red clay was measured by penetration test. The impregnation depth of foam in red clay was analyzed. The results provide key parameters for shield construction to prevent engineering accidents, such as, flowing, sand gushing, mud boiling, collapse and so on.
Calculation of the Natural Frequencies of Transverse Vibration of Complex Beams Using the Differential-Matrix Equations
Authors: Zhang Yu
Published: May 2011

The generalized differential-matrix equations of transverse vibration of the beams were set up and they were solved by means of Cauchy sequence iterative method. Then according to the boundary conditions at two ends of the beams the natural frequencies of the transverse vibration of the different beams including the complex beams of non-uniform section and composite beams under different boundary conditions were figured out. The form of the differential-matrix is simple. The calculation of the sequence iterations can be accomplished by simple computer program. Using the method in this paper, the amount of work of calculation is reduced greatly and the results are accurate compared with the approximate method in which a beam of non-uniform section is replaced by many small segments of equal cross-section.
Design Method and Application of the Capped Rigid Piles and Geo-Synthetics Composite Foundation
Authors: Cheng Ze Hai
Published: May 2011

The composite foundation with capped rigid piles and geo-synthetics is a new technology. A plane of equal settlement exists in the fill through soil arching. The horizontal membrane can restrain the lateral deformation of the pile and subsoil. Most loads can be effectively shifted to the piles and the deep layer. The total settlement and differential settlement can be controlled. The technology is particularly fit for soft soil ground treatment engineering. The mechanism of interaction among fill, foundation soil, geo-synthetics and pile (caps) was analyzed. A theoretic design method of the composite foundation with capped piles and geo-synthetics has been presented and a project case was cited in the paper. This study will improve the design theory of ground treatment.
Research on Settlement Calculation of Soft Foundation Treated with Vacuum Preloading Based on Stress Path Method
Authors: Wu Yue Dong , Yang Shang Chuan , Liu Han Long
Published: May 2011

Stress state of soft soil foundation under vacuum preloading is completely different from its counterpart under surcharge preloading, and the method of calculating the final settlement of soil mass by means of surcharge preloading (positive pressure) is unreasonable in present design. According to a case of soft foundation stabilized with vacuum preloading and through consolidated-undrained triaxial (CU) test on the specimens sampled in situ, the stress paths under different confining pressure are obtained. The settlement of soft foundation treated with vacuum preloading is calculated by strain isoline method. Compared with the practically measured field data, the errors are analyzed and discussed.
Experimental Research on Deformation Characteristics and Energy Change of Rock under Different Unloading Rates of Confining Pressures
Authors: Han Xian Min , Li Shou Ding
Published: May 2011

Experiments of unloading confining pressure of rock were conducted to reveal deformation characteristics of rock mass under different excavation intension in thigh geostress condition. It were concluded from tests that volumetric strain of rock is inverse proportional to unloading rate. The smaller the unloading rate, the bigger the ductility of rock. Energy release are bigger under high unloading rate than that under low unloading rate. That means that tendency of rock burst turn smaller when unloading rates decrease.
The Analysis on the Effect of the Loading Capacity of the Pile with Buried Tubes
Authors: Wang Wen , Han Rui , Wu Man Xia , Zheng Chun Mei
Published: May 2011

The pile ground heat exchanger is devised to overcome the shortcomings in configuration of existing ground heat exchangers. In view of its engineering applications of the spiral tubes ground heat exchanger inside foundation piles, the effects of them on the loading capacity features of the pile are studied. Firstly, a spiral tube model is proposed for the energy pile system and the model is proved correctly compared with engineering practice of the piles.Then，in the FEM software the model is applied in the comparasion between the piles with and without buried tubes .As a result, the effects of buried tubes on the loading capacity features of the piles are found.
Pedigree Cluster Analysis of Micro-Structural Parameters of Loess
Authors: Gao Ling Xia , Yang Xiang Yun , Li Shun Qun , Qin Li Kun
Published: May 2011

Based on the principle of pedigree cluster, recursion formulae of distance between micro-structure parameters are given. Then, pedigree cluster method and corresponding process for loess micro-structure parameters are proposed to classify micro-structural characters of loess before and after collapsing. The study results indicate that micro-structures of loess before and after collapsing have significant cluster characters. The grain on horizontal section is considered as isotropic. Geometrical anisotropy of the grain on other sections is distinct. The proposed method can evaluate the difference of grains in study field in size, shape, deposition, direct, area distribution and grey distribution.
Analysis on Dynamic Stability of Cuneiform Pile under Vertical Harmonic Loads
Authors: Sun Qiang , Lin Qiu Yi
Published: May 2011

We discussed the problems of dynamic stability of cuneiform pile under vertical dynamic load, and studied the influence of parameters resonance and soil resisting force on dynamic stability of foundation pile.
Analysis on Excavation Procedure in Large Soft Soil Foundation Pit of Shanghai Expo Axis
Authors: Yuan Xiang , Gong Quan Mei , Zhou Shun Hua
Published: May 2011

On the basis of the large soft soil foundation pit of Shanghai Expo axis and the Section 1 of underground complex project, this paper proposes the appropriate excavation procedure according to the results obtained by using centrifuge model tests and time hardening creep model, which uses ANSYS to compute foundation pit deformation caused by different excavation timeline, sequence and longitudinal excavation width of remained berm. The results of numerical calculation were approximately close to the horizontal displacement of the underground diaphragm wall measured both on site and from centrifuge model tests, so numerical calculation could well reflect the deformation behavior of excavation. The study also showed that more than 80% of underground diaphragm wall deformation caused by soil creep occurred within 60 days after the remained berm being excavated. In order to decrease the deformation, it would be useful to conduct plate structures as soon as the remained berm started being excavated. Remained berm and middle plate had good control over underground diaphragm wall deformation. When the remained berm was excavated by jumpily digging method, it would be advisable to firstly excavate the vicinity of underground diaphragm wall where there were no required protected objects nearby. The longitudinal excavation width of remained berm was proposed to be 20 meters in the north part and 30 meters in the south part.
Mechanical Characteristics of Soil Anchor under Combined Water and Ground Loads
Authors: Hao Jian Bin , Men Yu Ming
Published: May 2011

Gradually, anchor is in the working state of tension, but its stress becomes rather complicated when influenced by some external factors such as water, ground loads, etc. Aiming at the problems that ground additional load or coupling action of water and the additional load are forced on soil slope, the axial strain distributions of anchor tendons were obtained by model test. The change rules of axial strain at anchor head, near to slip plane, and end of the anchorage were analyzed respectively. The results show that under ground loads, the strain of anchor is biggest at the anchor head, and it gradually decreases from outer to inner. Under combined water and ground load, the stress state of the anchor system changes from tension to bending, and the upper anchors are most urgently affected. The experimental results can supply a reference for design and research of soil anchor with similar conditions.
Research on Topological Structure of Rock Electrochemical Impedance Spectroscopy
Authors: Wang Hong Fang , Hu Jiang Chun
Published: May 2011

It is important of rock crack fine test for deep rock engineering. The high frequency part of Nyquist diagram of rock electrochemical impedance spectroscopy reflects the rock volume change characteristics, which can express the change information of rock internal cracks. With the topological theory, the topological characteristics of Nyquist diagram of sandstone, mudstone and granite are researched. The results show that the electrochemical impedance spectroscopy diagrams which come from the same size sample using the uniform test are isomorphism, and which can express using the same function. It shows the rock electrochemical process is regularity. At the same time, topological separation of rock electrochemical impedance spectroscopy diagram is researched. Fine change of rock crack can be detected with topological separation.
Nonlinear Analysis of Pile Group Effect of Large Diameter Drill Hole Cast-in-Place Pile
Authors: Du Juan , Han Jian Gang , Zhang Hua Li , Zhong Jin Yu , Peng Hong
Published: May 2011

This paper adopts large diameter drill hole cast-in-place Pile of one Highway Bridge as the study case, using the pile calculatingly program, GPILE, that is a part of the common program software system of finite element method, SAP84, to analysis the pile group effect of large diameter drill hole cast-in-place Pile with different coefficients of pile group effect. This paper suggests using the ratio of the volume of pile and soil in the ambient range of pile group to express the new reduced coefficient and introducing the p-y curves of pile group after reduced as horizontal interaction model. Under these conditions, pile group nonlinearly effect of large diameter drill hole cast-in-place Pile is analyzed. At the same time, some different coefficients of pile group effects were calculated using this method. Compared these results, the feasibility and conciseness of reduced coefficient are testified.
The Application of the Capped PTC Pile in Expressway Widening on Soft Foundation
Authors: Liu Chun Yuan , Song Hai Chao , Pan Gong , Zhang Jun Qi , Liu Cheng Wei
Published: May 2011

Prestressed Tubular Concrete pile (PTC pile) with individual cap is applied in soft ground treatment in the widening project of Jin-bin expressway. The observed data on embankment settlement, soil pressure, pore water pressure and lateral deformation, investigate the effect of the application of PTC pile in soft ground improvement for extension project of Jin-bin expressway in Tianjin soft area.
Analysis of Influence of Design Parameters on Ultimate Bearing Capacity of the Steel Spatial Tubular Joint
Authors: Zhu Rui Tao
Published: May 2011

Utilizing general finite element software ANSYS, the finite element computing model of the steel spatial tubular joint is built, which is used to analyze the mechanical properties under dead loads through changing its design parameters. According to the obtained and compared consequences, the different design parameters including stiffening ring thickness, cross-shaped ribbed plate thickness and stiffening ring length exert different influence on ultimate bearing capacity of the steel spatial tubular joint. Specifically, the ultimate bearing capacity under dead loads is affected by setting stiffening ring and changing cross-shaped ribbed plate thickness significantly. In contrast, if the thickness and length of stiffening ring are changed, the impact is insignificant. The results and conclusion can provide reference which is useful to optimize the design of steel spatial tubular joint in such category.
A Simplified Method to Assess the Risk of Geotechnical Engineering under Hydro-Chemical Corrosion
Authors: Li Peng , Li Guo He , Liu Jian
Published: May 2011

Rock mass are subject to continuous changes induced by physical and chemical processes of natural and anthropic origin. Such changes affect their mechanical properties. To quantitatively evaluate the hydro-chemical corrosion, the theories of chemical thermodynamic and chemical kinetics are introduced. An index was proposed, which provides a criterion to judge whether the corrosion would be happened and indicated the reaction direction. Then based on theoretical and testing results, a hydro-chemical damage index was proposed. And a series of damage degrees of sandstone under different circumstances, which consider the variations of pH values, temperatures, ions species and ions concentrations, were calculated by chemical kinetics method. Based on the results, the sensitivity of influencing factors was discussed. According to the calculation and the theory of poromechanics or testing results, the mechanical properties of geotechnical materials under hydro-chemical corrosion process can be predicted, so can assess the risk of geotechnical engineering long-term stability.
Gravel Pile of Dry Mixed Cement Trial Research in Reinforcing Subgrade
Authors: Zhou Min , Wang Du Bo , Zhang Xu Zhu , Geng Ji Guang
Published: May 2011

According to the Beijing-Zhuhai Expressway K421+642~K421+975 Subgrade disease problems, it is reinforced by dry mixed of cement rubble pile. In order to study the reinforcement effect, the test site is divided into 5 sections and each section has six piles, the length of pile is 6.0m, the diameter of pile is 150mm, the pile spacing is 1m×1m and the weight of hammer is 120Kg. The packing height of pile and the compaction number of pile per layer is different on each section. By analyzing the results of the loading tests and the dynamic penetration test, when the packing height is less than 40cm and the compaction number is more than 7, the pile body is closely dense state and bearing capacity characteristic value is 340Kpa, and meet the design requirements; The variation is comparative analyzed by the results of the CPT, Rayleigh wave test and laboratory tests of the reinforcement of subgrade before and after, the water content of reinforced subgrade is decreased, the subgrade bearing capacity and settlement is improved. Subgrade diseases have not been detected after they were treated one year. The analysis and control methods provide references for similar projects treatment.
Study on the Displacement Characteristic of Uplift Anchor under Cyclic Loading
Authors: Zhang Zhong Miao , Liu Nian Wu , Fang Kai , Zhang Qian Qing
Published: May 2011

This paper presents the results of the cyclic loading tests for 30 uplift anchors. The relationship between the loads and displacements for each anchor under cyclic loading is studied and the results show that the behavior of the anchor is largely influenced by its length. It is common for the Q-S curves of different anchors to vary quite widely. The displacements under different load levels decrease with increasing anchor length but the decreasing rate has a number of variations. It is also found that the final displacements of the anchors are dominated by plastic displacements which positively correlated with the peak loads. In addition, the effective length of the anchor is related to the load acted on it.
The Application Process of Wavelet Neural Network in Intelligent Evaluation of the Quality of Engineering Anchor Poles
Authors: Li Rui Jun , Shi Ya Qing , Ma Jian Suo , Jiang Xi Yan
Published: May 2011

Most detection means on the anchorage integrity today still remain on the destructive testing level, which can hardly meet the actual needs of quality detection on large volumes of anchor poles in the anchorage engineering. This paper presents the application process of wavelet neural network in the non-destructive intelligent testing on the quality of engineering anchor poles. Taking the project of "Management Buildings and Museum of China Marine Sports School" in Qingdao as an example, this paper uses neural toolbox of MATLAB to do the network training by selecting training and simulation samples. The ideal training results indicate that with the help of neural toolbox of MATLAB, the application process of wavelet neural network can not only make intelligent evaluation of the quality of engineering anchor poles, but also make up traditional means, which can not detect large volumes of anchor poles.
Numerical Simulation of Triaxial Test in Clayey Soil Using Different Constitutive Relations
Authors: Fattah Mohammed Y. , Salman Firas A. , Nareeman Bestun J.
Published: May 2011

The stress paths to which specimens are subjected in triaxial tests together with the yield surfaces, which may be exercised in different models of such a test are simulated. A laboratory testing on undisturbed clay soil samples was performed in order to characterize the stress-strain behaviour of the residual soils in Sao Paulo sedimentary deposit. The sample is tested under isotropically consolidated drained triaxial compression. Strain controlled procedure was used to simulate stress-strain relationships of the soil. Seven models are used; namely: linear elastic, Duncan-Chang hyperbolic, Mohr-Coulomb, Cam clay, modified Cam clay, new Mohr-Coulomb and Cap model. It was concluded that the results of Cam clay and Duncan Chang models are the closest to the experimental data under low confining pressures; 49 and 98 kPa. Both models exhibit parabolic stress-strain relationships while the linear elastic model results are far away from experimental ones especially at large stress levels. At high confining pressure; 196 kPa, the modified Cam clay best correlates the stress and strain.
Stability of a Cracked Viscoelastic Plate of Varying Thickness Subjected to Follower Force
Authors: Wang Yan , Wang Zhong Min
Published: May 2011

The stability of the cracked visoelastic rectangular plate of varying thickness subjected to uniformly distributed tangential follower force is investigated. Two models describing thickness variation are parabolic and linear variations along one edge of the plate. This is done in order to show how critical loads for cracked visoelastic thin plate subjected to follower force can be obtained using the two-dimensional viscoelastic differential constitutive relation and the thin-plate theory. The differential equations in the Laplace domain are established. The complex eigen-value equations are derived by the differential quadrature method. The generalized eigen-value under different boundary conditions is calculated. The effects of the plate parameters, the crack parameters and the dimensionless delay time on the stability of the viscoelastic plates are analyzed. The crack is found to change the type of instability and reduce the stability of varying thickness viscoelastic plate.
The Analysis of Loess High Embankment Stable Question by the Strength Reduction FEM
Authors: Zhang Li Ping , Liu Chao
Published: May 2011

The slope of loess high embankment stability analysis is in northwest loess area highway construction important question, also is in the crag earth project discipline one of most ancient model research topics. This article folds the subtraction analysis loess high embankment stable question with the strength reduction FEM, not only can direct—viewing see the soil body stress strain the development change, moreover may obtain the slope and stability the coefficient. This article folds the subtraction obtained stability coefficient with the strength reduction FEM to be smaller than the bishop law obtained stability coefficient.
System Implementation on Fuzzy Comprehensive Evaluation of Slope Stability Based on GIS
Authors: Zhao Jun Lan
Published: May 2011

Application and research of GIS in the slope engineering is one of the hot topics in this field. In this paper, the fuzzy comprehensive evaluation method of slope stability based on GIS was researched. It developed and set up a multi factor slope fuzzy comprehensive evaluation system by using slope database and can quantitatively classify and evaluate the slope stability in a quick and efficient way. This system can be at work on slope data management, inquiry, statistics and spatial analysis. It evaluated the fatality and vulnerability to the slope of a large scale coal mine as an example.
Experimental Study on Anchoring Bond Behavior of Pre-Tensioned Prestressed Concrete Beams with Corroded Steel Strands
Authors: Li Fu Min , Shi Xiao Fei , Jia Fu Ping
Published: May 2011

To study the influence of steel strands corrosion on the bond behavior for anchoring of pre-tensioned prestressed concrete beams, nine specimens were fabricated. Of which, 5 beams were mixed with salt and set in different places to be corroded in different intensity for 13 months. Then the load test was held to all the 9 specimens and the load-slip curves were obtained. The results show that under the condition of no corrosion crack, the short-term anchoring bond strength of pre-tensioned prestressed concrete beams increases for the steel strands corrosion. Because the tension behavior of steel strands deteriorates remarkably even if the corrosion is slight, which is the dominant cause for the degradation of fundamental structural behavior, the influence of steel strands corrosion on the bond behavior for anchoring may be ignored.
Swell-Shrinkage Behavior of Remolded Expansive Soils
Authors: Yu Cheng , Wei Jin Cheng
Published: May 2011

The swelling behaviour of compacted expansive soils have been studied with variation in initial state. For comparison, a series of swell and shrinkage capacity laboratory tests with different initial dry densities，moisture contents and pressures have also been made with three different consistency state. Both percent swell and shrinkage are significantly influenced by the consistency state index. There is an unique relationship between percent swell and consistency state index of the soil. The percent swell-load relationship could be identified as a logarithmic relationship facilitating the prediction of ultimate percent swell under different load with a few initial results.
Random Variation of Soil Parameters on the Reliability of Slope Stability
Authors: Ge Hai Yu , Tu Jin Song , Xia Song , Ge Qing Yun
Published: May 2011

An expression for slope stability and safety factor is established herein by using inclined slice method based on limit equilibrium condition theory. A limit state function for the reliability analysis of slope stability is established as well. Such analysis is carried out by using the Monte Carlo method so as to study effects of random variables of soil parameters such as adhesive force, internal frictional angle and average values of soil density, together with their coefficients of variation, on reliability index of soil. As demonstrated by the examples described herein, these coefficients of variation are linear with the reliability indexβ, which indicates that soil of low discreteness is available with high reliability index and vice versa. As such, the analysis by using the Monte Carlo method can provide theoretical basis for determination of stability of soil and thus is highly practicable in actual engineering and construction.
Formation Mechanism Study on Houchuangzi Slope Debris Flow
Authors: He Xiao Ying , Chen Hong Kai , Tang Hong Mei , Wen Guang Ju
Published: May 2011

Taken the Houchuangzi slope debris flow along Kunming- -Songming highway as instance, analyzed the mineral composition of provenance on the slope debris flow adopted the polycrystal X ray diffractometer, which was rich in hydrophilic clay mineralssuch as kaolinite and montmorillnite; analyzed the fornation mechanism of the HouChuangzi slope debris flow by the laboratory model test, compartmentalized the fornation process of the HouChuangzi slope debris flow in to five stages from the aspects of slope debris flow morphology and crack extension mechanism.The results provide certain reference value for further research of the formation mechanical mechanism.
Research on Un-Linear Deformation Characteristics of Unsaturated Clay with General Triaxial Test
Authors: Shen Xi Zhong , Zhang Jin Xia , Zhang Min
Published: May 2011

Difficult in soil-water characteristic curve achieved, existence of non-uniqueness and indistinct in influence of unlinear deformation characteristics of soil about density and water content, deformation characteristics of unsaturated soil were studied difficultly with general triaxial test, thus direct application of unlinear Duncan-Chang model in unsaturated soil was restricted. General triaxial tests with combined dry density and water content are carried out, changing rules of parameters of Duncan-Chang model are summarized, mathematical functions between dry density, saturation and parameters of the model are established. Analysis shows that deformation characteristics of unsaturated clay are influenced obviously by saturation and dry density. Among them, the larger the saturation, the higher strain becomes under the condition of the same dry density and main stress difference, and the less the dry density, the higher strain becomes under the condition of the same saturation and main stress difference. Moreover, the main parameters of Duncan-Chang model keep close correction with dry density and saturation, and the both mutual effect can be expressed by multiplication. This shows that mechanical characteristics of unsaturated soil can be studied with general triaxial test, thus it will be used easily in project.
Numerical Simulation Research for Stress and Distortion of Pile-Anchor Support Structure of the Deep Foundation
Authors: Liu Bang Jia , Xu Qian
Published: May 2011

This article has used the ADINA numerical calculus software to simulate the deep foundation excavation and supports process, as well as analyzing the analogue result in the project of the Xia Gong in ShenYang City. The results illustrate that (1) it is essential to optimize the pile earth's horizontal displacement and the mechanical situation of anchor rod. (2) It makes soil’s horizontal displacement and the mechanical situation of anchor rod more reasonable by changing the anchor rod vertical spacing and length ，hence obtains that the anchor parameter change has the great influence on the distortion of the support structure.
Studies on Soil Resistance to Pipelines Buried in Sand
Authors: Liu Run , Guo Lin Ping , Yan Shu Wang , Xu Yu
Published: May 2011

A series of model tests were carried out to investigate the soil resistance when the buried pipe segment moved in the sand. In the tests, the pipe segments were pulled out in vertical, lateral and axial directions and the pipe segments movement and soil resistance were recorded. Observed data show that the soil resistance depends on the pipe diameters and the depth of cover. According to the uplift test results, the force-displacement relationships with smaller depth of cover are greatly different from those with larger depth of cover. The results of the lateral sliding and axial pull out tests show that the soil resistance initially increases before a peak value is reached and then keeps the same level. For the same covered depth, the lateral soil resistance is more than twice that for uplift. According to the uplift test results, the soil failure modes with smaller depth of cover are greatly different from those with larger covered depth.
Micro-Numerical Simulation of Anchorage Performance for Geotechnical Anchored Structure by Particle Flow Code
Authors: Zhang Si Feng , Li Yan Mei , Song Xiu Guang , Zhou Jian , Cui Jian
Published: May 2011

Based on the theory of particle flow code, the micro-numerical analysis model is established to study the anchorage performance of geotechnical prestressed anchorage structures. According to the numerical model tests, the development regularity of stress and displacement of surrounding soil around bar body under the effect of uplift loading is analyzed, and the interaction characters between anchor bolt and surrounding soil are also deeply studied. Conclusions can be drawn as follows: with the function of tensile load, two area of stress concentration form within the interior bond section of prestressed anchorage structure, and the soil porosity also changes accordingly. The interface shear stress peak point shift inward gradually with the increase of time-stepping, furthmore, the peak stress also enlarges gradually. According to the deformation mode, the surrounding soil can be divided into three zones. The radial displacement of soil between anchors is weakened because of the effects of group anchors, but the axial displacement is strengthened, which nominally is similar to the “single anchor character”. The research findings have a certain reference value for the study of anchorage mechanism.
Inversion on S-Wave Velocity Structure of Shallow Soil Layer Site Using Parallel Genetic Algorithm
Authors: Dong Lian Cheng , Li Guang Ying , Tao Xia Xin , Lu Da Gang , Liu Juan , Hu Xin Fu
Published: May 2011

Microtremors was developed to inverse S-wave velocity structure of sites because it costs little and easy to monitor, can be performed at any place even in a densely populated city with non-destructive measurements, the genetic algorithm is widely used in inversion and there are many disadvantages in using genetic algorithms to solve practical problems, so the authors did a lot of efforts to overcome these disadvantages. In order to solve these disadvantages, a coarse-grained parallel genetic algorithm(PGA) based on personal computer cluster was proposed to inverse S-wave velocity structure of shallow soil layer of actual engineering sites, the simulated annealing algorithm and parallel technique message passing interface(MPI) were adopted to implement the coarse-grained parallel compute. The subpopulations were collaboratively optimized through individual migration strategy and the dynamic populations were adopted to balance the computing load. The shallow S-wave velocity structures of two examples and the actual engineering sites were inversed through a 4-node PC cluster test system, the results showed that the algorithm has a good parallel efficiency and can be used in engineering site.
Physical Modelling of Joint Effects on Deformation and Failure of Tunnels
Authors: Zhao Hai Jun , Ma Feng Shan , Guo Jie
Published: May 2011

The deformation and failure mechanisms of tunnels in jointed rock mass with variable orientation and overburden pressures were studied by physical modelling. The deformation and expansion characteristics and regularities of joints and its influence on the stability of tunnels were analyzed. The results shown that the effects of unloading and reactivation of joints, and subsequent shear slip and deformation induced by excavation cause the structural instability of tunnels. The deformation, failure, and instability of surrounding rocks are essentially the continued deformation and repeated failure of joints in varied stress field caused by excavation and overburden pressure. When the dip angle of the joint sets is 75°, the joints have extremely striking influence on the stability of tunnels. In addition, with the increasing of the overburden pressures, the deformation extent and failure rate are sped up prominently due to the rapid increasing of the shear stresses on joint planes.
Effect of Rock Nonhomogeneous Characteristics on Threshold Permeability
Authors: Feng Zeng Chao , Wang Jiang Fang , Zhao Dong
Published: May 2011

Permeability is one of an important characteristic of rock materials. The connectivity of permeate passageways could be used by probability of threshold permeability for evaluation. In the foundation of micro CT scan figures of rock samples, nonhomogeneous density distribution of inner rock is studied and connectivity rough of rock by threshold permeability program is also calculated. And the results are: the distribution of rock permeate passageways is nonhomogeneity and the probability of rock threshold permeability is also greatly declined, which is determined not only by ratios of nonporous particles but also by space distribution styles of porous medium.
3D Back Analysis of Initial Stress Field Based on Neural Network RBF Model
Authors: Wang Zhong Fu , Liu Han Dong , Jiang Tong , Wan Si Wei
Published: May 2011

Based on geological condition of underground factory building in Hohhot pumped storage power station, research and analysis are taken for the fundamental element which affect initial stress field, 3D finite element model of underground factory building is build for the analysis. Beigin with regrssion analysis, adopt linear elasticity caculation of finite element method to take linear regression analysis, and obtain range of optimized parameters. Adopt homogeneous design to definite various assemblies of optimized parameters at different levels. Obtain training sample by elasto plastic caculation of finite element, train for RBF model in oder to get inverse model of ground stress field. The calculation result shown that: RBF model overcome the disadvantages such as slow calculating speed and overfitting of BP model, and it could obtain distrubution rule of initial stress filed by inverse analysis in a reasonable way.