bluuebunny/crossref_metadata_2025 huggingface dataset:
Behavior of Micropiles in Soft Soil under Vertical Loading
Authors: Qian Zen Zheng , Lu Xian Long
Published: May 2011

The behavior of micropiles in soft clay, under vertical compression and tension loading, was examined by field tests at a site in Shanghai. The soil profile consists of topsoil, silty clay, sandy silt, muddy clay, and clay soil. Two compression and three tension loading tests were conducted on five single micropiles. The piles were instrumented with vibrating wire force sensors, and they were monitored during the process of loading to investigate the mechanisms of load transfer. Both the ultimate vertical load capacity and the deflection at applied loads were examined. The results indicate that the pile load–displacement response under vertical compression or tension loadings was nonlinear. Both the compression and the tension load carrying capacity basically increased with a linear trend. But, the ultimate load capacities under tension were about 50-60% of those under compression. Tip resistance was about 10-15% of the applied compression load, not existing in the micropiles under tension. The average skin friction for micropiles under compression loading was about 50% higher than that for piles under tension loading.
Testing Analysis on Rock Fatigue Life Due to Affecting Factors under Uniaxial Compression
Authors: Ren Jian Xi , Zhang Yin He , Li Qing Yuan , Zhang Kun
Published: May 2011

Using the rock mechanics multi-function testing machine named RMT150B, the testing study on rock fatigue life due to different affecting factors under uniaxial compression condition are accomplished. It is the study emphasis that the influence mechanism of rock sample fatigue life due to different stress amplitudes, waveforms and frequencies .It shows that the stress amplitude, waveform and frequency can all remarkably affect the rock fatigue life. The influence essential reason of rock life due to different stress amplitudes and waveforms is the different dissipation of energy. And the influence essential reason of rock life due to different frequencies is the different loading rate of speed.
A Constitutive Model for Rock Joints under Cyclic Loading
Authors: Yang Dong Mei , Qiu Xiang Bo
Published: May 2011

Cyclic loads are commonly encountered in geotechnical engineering; however most constitutive models do not account for the effect that such loads can have on the mechanical behaviour of soils and rocks. This work is concerned with the behaviour of jointed rock and, as the overall mechanical behaviour of jointed rock is usually dominated by the mechanical behaviour of the joints, it is focused on the behaviour of rock joints under cyclic loads. In particular, an extension of the existed constitutive model for cyclically loaded rock joints is presented. Variations of rock joint stiffness in both the normal and the shear directions of loading due to surface degradation are taken into account. The degradation of asperities of first and second order is considered, while a new relation is proposed for the joint stiffness in the normal direction during unloading. Numerical simulation results show good agreement of model predictions with existing experimental results.
Experimental Study on Variation Law of Permeability Coefficient under Muddy Water Infiltration
Authors: Jin Jia Xu , Liang Li , Liang Bing , Li Ming , Zhang Kai
Published: May 2011

The porosity of solid skeleton is changed under muddy water infiltration, and thus the permeability is also changed. A concentration of 30% muddy water compared with clear water, is experimented to simulate the movement of small particles. The relationship between solid skeleton permeability, porosity and time is obtained from experiments. The relationships among fraction void and permeability coefficient in such cases are presented. The relationship expressions are studied. Some novel laws are obtained as follows: because of the hindrance effect by the small particles, permeability coefficient decreases gradually over time, but clear water has no influence on the permeability coefficient; at the beginning, the porosity of solid skeleton decrease rapidly over time. Then it is stabilized latterly, they two are in monotone decreasing parabolic curve relationship; The relationship curve of cumulative infiltration capacity and time is a monotonically increasing curve which slope becomes smaller; the infiltration concentration fall first and rises later. The results provide a theoretical basis for muddy water infiltration.
Experimental Study on Time Series Characteristics of Rock Acoustic Emission in Complete Stress-Strain Process under Uniaxial Compression
Authors: Yang Yong Jie , Wang De Chao , Wang Kai , Zhao Nan Nan
Published: May 2011

Analysis of rock acoustic emission characteristics in complete stress-strain process under uniaxial compression shows that the evolution process of rock deformation and damage can be divided into five stages—compaction, linear elastic deformation, accelerate inelastic deformation, damage and development, plastic flow. Acoustic emission characteristics of rock can well reflect its compressive deformation and damage evolution process. Acoustic emission time series of typical plastic coal is comparatively dispersed and presents group shock type. The acoustic emission frequency events and their energy of coal are bigger around the damage point, but the maximum amplitude and the secondary maximum amplitude have not much difference. The acoustic emission events and their energy of very uniform and dense fragile limestone are mainly concentrated in a very short period of time before its damage and the acoustic emission time series manifests as isolated shock type. For sandstone whose homogeneous degree lies between typical plastic coal and very uniform and dense fragile limestone, its acoustic emission time series manifest as main shock type.
A Study of the Vibration Impact of Underground Circular Structure on the Surrounding Buildings
Authors: Ren Qing , Liu Xue
Published: May 2011

The finite element model with artificial boundary was used to simulate dynamic response of an underground circular structure (tunnel, cavern) and displacement of the ground surface under incidence of Rayleigh wave, and to quantitatively analyze the effects of incident wavelength, diameter of structure, and liner stiffness on ground surface displacement amplification. The numerical results show that, the surface displacement amplitude with a tunnel can be 1.3 times of that for the case of without the tunnel. It is suggested that the effects of a tunnel on ground motion should be considered when the tunnel is planned and designed.
Stability Analysis of Rock Slope Based on Preferred Structural Plane
Authors: Zhong Wen , Tan Zhuo Ying , Qiao Lan
Published: May 2011

Aimed at stability of rock slope, the attitude of structural plane is statistically analyzed with a combined method of rose diagram and pole equidensite diagram, and the preferred structural planes which are dominant in stability of slope were further determined by a lot of factors such as the terrain and topographical features of slope, the lithologic characters and the development of structural plane. Besides, the stereographic projection method is applied to qualitative analysis for the stability of rock slope. The results show that preferred structural plane can effectively reveal the nature of rock slope stability and provide a dimensional discriminant approach for stability of rock mass slope.
Approximate Analytical Method of Load-Settlement Relation for Composite Foundation under Embankment Load
Authors: Liu Jie , He Jie , Liu Fang
Published: May 2011

Considering reinforcement zone and natural foundation as a whole, the displacement component formulas satisfy with the displacement boundary conditions were constructed based on some hypotheses. Considering friction influence under foundation, a approximate analytical algorithm of foundation deformation was established under embankment loads by the variational method of displacement, and the approximate analytical formula on the relationship between the load and the average settlement was derived. The static load model tests were carried out in laboratory to verify the feasibility of this method proposed in this paper.
Nonlinear Finite Element Analysis on Frame Joints of Steel Truss SRC Beam
Authors: Tang Guang Xian , Jia Zhi Chao , Deng Zhi Heng , Lu He Yong
Published: May 2011

To understand mechanical characteristics of frame joints of steel truss SRC beam, the accuracy of the proposed method is proved by the comparison between FEA result and test result, considering different steel ratios, cross flank rods and axial loads as well as plastic model of concrete damage. The result indicates that cross section and steel can delay joint damage and improve the bearing capacity, and that axial load can improve joints shear capacity to some extent but joints ductility is decreased, and that constraint of steel to concrete improves brittleness character caused by bad ductility of concrete.
Field Performance of a Deep Multi-Strutted Excavation in Hangzhou Soft Clays
Authors: Ying Hong Wei , Yang Yong Wen , Xie Xin Yu
Published: May 2011

A case history of a deep multi-strutted soft clay excavation in Hangzhou is presented in this paper. What makes it particular interest is its three characteristics: large scale, deep excavation and very soft clays. The excavated area was about 99750 square meters. The depth of excavation was 12.85 m. 4 m below the ground surface located about 24 m very soft soil clays. Wall deflections and ground settlements were measured and compared with similar case histories worldwide. It was shown that the maximum horizontal deformations of the excavation was very large which this excavation reached to 220 mm. “Creep” deformations occurred apparently during the curing of the bottom slab of the basement. The distributions of the surface settlements seemed to be parabolic, and the settlement influence zone could reach to a distance of more than 2H, whereHis the final excavation depth. The ratio between the maximum ground settlement and the maximum horizontal deformation of the wall is about 0.6.
Evaluation on Excavation Design with VE Method
Authors: Tong Hua Wei , Chen Hai Ying
Published: May 2011

This paper obtains function index system of excavation by FAST method and introduces two-class fuzzy comprehensive evaluation to estimate function index system. By analyzing the excavation's life-cycle costs obtains the evaluation method for excavation design cost, proposing new evaluation standards for excavation design. At last establishing value engineering (VE) evaluated model for excavation design, and put it into engineering practice to prove that the model is convenient and practical, simple, fast, and accurate.
Shear Mechanism and Bearing Capacity Calculation of Composite Joints with Steel Truss SRC Beam
Authors: Deng Zhi Heng , Tang Guang Xian , Jia Zhi Chao , Lin Qian
Published: May 2011

In order to research the seismic performance, eight joints with steel truss SRC beam and RC column under low-cyclic reversed load was conducted, and the failure process and patterns were observed. The test indicates that two types of failure patterns can be seen from specimens, including shear failure and bending failure. By the analysis of the failure characteristics and mechanism of joints, the load-displacement hysteretic curves and load-strain hysteretic curves are presented, and the formula for calculating ultimate shear capacity of joints is gained finally. The calculating results are in good agreement with those of tests.
Study on the Effect of Hydraulic Immersion on the Strength and Deformation Characteristics of Sandstone
Authors: Wang Rui Hong , Jiang Yu Zhou , Guo Jing , Zhou Ji Fang
Published: May 2011

During the hydraulic structure design, the stability of abutment slope is critical to the normal operation of hydraulic structure. Through the tests, the effects of different hydraulic pressure on the strength and deformation characteristics of sandstone were studied, and the variation characteristics of rock masses with joints under secondary loading after excavation damage were analyzed as well. Test results show that: 1. When the samples without immersion secondly load until complete failure, ultimate strain increases slightly than the first loading, of which the increasing value is 7.5%; elastic modulus has a relatively large reduction than the first, which reduces 22.8%; deformation modulus has a less reduction, which is about 3.3%; 2. When considering the softening action of different hydraulic pressure on samples, ultimate strain increases by about 23% than that without consideration of immersion effect; elastic modulus reduces about 53%; deformation modulus reduces about 39%; 3. With the increment of immersion pressure, sample strength decreases greater, so does the softening effect of water on rock samples. With the increment of pressure, the strength of rock with joints has a relatively large reduction, which is from 27% to 41%, and the increasing value of intact rock mass isn't great, which is only from 25% to 27%. Jointed rock masses are more sensitive to the softening effect of water, and mechanical properties weaken obviously after long-term immersion with unstable problem.
Analysis of Frozen Drilling Surrounding Rock Temperature Field about Weakly Cemented Soft Rock
Authors: Wang Wei Ming , Wang Lei , Jia Hai Bin
Published: May 2011

This paper mainly introduced the monitoring scheme of one mine’s wind well in Inner Mongolia. By analyzing the monitoring data at different depth, rules of the freezing temperature field were drawn. Fitting the monitoring data linearly at freezing and thawing phrase respectively, the experience formula of time prediction at the two phases were obtained. Meanwhile the temperature diffusion coefficient of sandstone and mudstone layers were revised, which can provide scientific basis for some similiar shaft construction.
Prediction on Red Clay Foundation Settlement of Ballastless Track of High-Speed Railway
Authors: Yang Xiao , Yang Guo Lin , Fang Wei
Published: May 2011

Prediction on red clay foundation settlement was put forward, using hyperbola method, exponential curve method and Hushino method, based on field data. Furthermore, Verhulst model, Gompertz model, Logistic model and Weibull curve were adopted in foundation settlement prediction. Subsequently, variable weight combination method and optimized combination model was studied to get more accurate prediction results. Finally, red clay foundation prediction of high speed railway was proposed.
The Application Study of Self-Balanced Test Method for Bearing Capacity of Foundation Piles
Authors: Dai Zi Ran , Huang Zhi Hong , Li Hui , Yin Xi Da
Published: May 2011

This paper introduced the application of Self-balanced Test Method for Bearing Capacity of Foundation Piles on a construction project of Gui Zhou province, while sorting out and analyzing the test data, the application results indicates that the method of the static load test is an effective and convenient method of testing technique. it can popularize the use in the similar projects.
Crack Growth Model under Creep-Fatigue Interaction
Authors: Zhang Rui , Li Hong Liang
Published: May 2011

In the present paper, a new creep-fatigue crack growth model of J-integral criterion is proposed. The model is built based on the dislocation-free zone (DFZ) theory and cohesive zone model. The process of crack growth is viewed as the intermittent quasi-cleavage fracture of the DFZ. The microscopic void caused by creep will grow and join the dominant crack under creep-fatigue interaction. In this process, material’s plastic deformation induces the change of the dislocation’s density. The redistribution of dislocation will change the value of J-integral within the cohesive zone. When the value of J-integral attains the critical value Jc, crack will grow by the original width of DFZ. Based on it, a simple relation is employed to evaluate crack growth rate under creep-fatigue interaction. The calculated crack growth rate curve exhibits three different regimes, which is in agreement with the general crack propagation pattern under creep-fatigue interaction. The model gives a reasonable explanation for crack growth under creep-fatigue interaction. The calculated value is close to the value obtained by experiment.
Numerical Simulation of the Rational Loading Waveform in Large Diameter SHPB Dynamic Test for Rock-Like Materials
Authors: Gong Feng Qiang , Liu Xi Ling , Gao Ke
Published: May 2011

For rock-like materials, large diameter SHPB (Split Hopkinson Pressure Bar,SHPB) is necessary and essential in dynamic test. Based on the finite element software ANSYS/LS- DYNA, the transmission of different stress pulse waveform in large diameter bar was simulated and the loading waveform dispersion effect was investigated in this paper. Three typical stress pulses (rectangular waveform, triangular waveform and half-sine waveform) with the same duration time and maximum stress amplitude value were loaded on input bar of SHPB. The time-stress curves of different transmission distance on input bar were traced and recorded and four specific aspects were discussed respectively. Compared with rectangular waveform and triangular waveform, the results of numerical analysis indicated that there isn’t pulse waveform dispersion for half-sine waveform to transmit in large diameter SHPB and there is enough increased time to satify stress equilibrium before rock-like materials failure. The half-sine stress wave is able to meet the one-dimensional assumptions in the propagation process and can be used in large diameter SHPB test.
Rainfall-Induce Seepage Field of a High Slope and its Effect Factors
Authors: Zhu Zhan Yuan , Zhang Feng , Ling Xian Zhang , Huang Man Qiang , Li Qiong Lin
Published: May 2011

To investigate the rainfall-induce the seepage field of a high slope and effect factors, the theory of saturated-unsaturated infiltration was employed, and the numerical model of slope infiltration subjected to the rainfall are developed and programmed. The numerical results shown that, (1) With the increasing of the rainfall duration, rainfall water infiltration formed a transient saturated zone at slope surface, when the moist frontal surface reached to the groundwater level, the rainfall water would supply the groundwater. (2) Each effect factors on the seepage field play a strongest roles on the slope toe, weaker role on the middle part slope and weakest role on the top slope. (3) The longer rainfall duration, the deeper of infiltration depth. It also be deeper with the larger rainfall intensity, coefficient of permeability, the initial moisture content of the surface and the surface waterlogging depth. (4) The effect on seepage field would be faintly and could be ignored when the rainfall intensity was greater than 65.9mm/h and the surface waterlogging depth is greater than 0.3m. All above could provide technical ideas for analyzing slope seepage field under rainfall and accumulate fundamental data for early warning and preventing mud-rock flow and landslide.
Corrected Cone Penetration Test Method for Predicting the Load Capacity of Single Pile
Authors: Jiang Dong Hai , Li Zhang , Ji Nai Jian , Hu Yuan Yuan
Published: May 2011

Based on the end bearing capacity and friction capacity obtained from high strain dynamic test, an adjusted equation was provided to calculate the pile load capacity. The equation was corrected again by pile load test results. Therefore, a suggested equation was finally established. Practical experience showed that, the corrected equation of cone penetration test method to estimate the load capacity of single pile performed better than that in the national code.
Experimental Study on Dynamic Poisson’s Ratio of Rock-Fill Materials under Cyclic Loadings
Authors: Zou De Gao , Liu Jing Mao , Xu Bin , Kong Xian Jing , Gong Tao
Published: May 2011

Dynamic Poisson’s ratio is a very important parameter for the numerical analysis of dynamic responses in a rock-fill dam. It is generally taken as a constant of which the significance is generally underrated. In order to have a better understanding of the dynamic properties of rock-fill materials, a series of tests were performed to investigate the effects of the shear strain on the dynamic Poisson’s ratio. The experimental results show that dynamic Poisson’s ratio varies with the shear strain, the dynamic shear modulus and the confining pressure. In addition, the empirical formulas to determine the dynamic Poisson’s ratio with the shear strain or normalized shear modulus are given in this paper.
The Analysis of Measured Data of Plant and Tree Growth with Richards and Logistic Model
Authors: Tai Bao , Gang Jiang
Published: May 2011

The main inﬂuences of plants on the mass stability of slope are those that affect the strength of soil. Plants enhance soil strength by directly reinforcing soil material with their roots. In this paper we do not consider slope hydrology but focus on quantifying increases in plant root growth. Root length is a function of growth time. In this paper, the sigmoidal models have been used to analyze plant root growth with time. Field studies of slopes of YU Tong road , two kind of tree, weeping willow, alamo and three kind of plant, Tall fescue, Bermuda grass and White clover indicate that slope reinforcement, due to the roots of these species, increases exponentially with time below the soil surface. Differences in the root length of tree and plant are illustrated by Logistic model, Richards model based on measured data.The measured data are a large scattering and is diffcult to find growth trend and predict the final length in one season. The data must be process before used in practical engineering. Sigmoidal models are a good tool to determine the growth-time curves of root length. For this purpose, two different sigmoidal models were used to define the curves of root growth, namely Richards model and Logistic model. The coefficients of Richards model for plant were 0.9964591, 0.998516, 0.9964465 and Logistic model for tree were 0.984001, 0.9957275 respectively. The analysis results show that Logistic model, Richards model are suitable models for explaining root growth.
Optimization Design Study on Variable Stiffness of the Pile Raft Foundation in High-Rise Building
Authors: Li Yong Le , Wang Jiang Feng , Wang Qian , Yang Kun
Published: May 2011

The finite element calculation results indicated: interaction of the superstructure-the pile raft foundation-foundation, the stress of the pile raft foundation appeared "disc type" distribution, namely, was big in the middle, and was small in the edge. Generation of differential settlement was due to the upper structure secondary stress and raft internal force. Through adjusting the foundation soil stiffness and pile length, pile diameter and pile distance, the influence of variable stiffness on differential settlement was analyzed. The results showed that changing the pile arrangement and adjusting the stiffness of foundation soil was optimal scheme of the pile raft foundation in high-rise building.
Probabilistic Evaluation of Effects of Column Moment Magnification Factor on Seismic Performance of Reinforced Concrete Frames
Authors: He Ming Ji , Yang Chun , Cai Jian , Huang Yan Sheng , Wu Yi
Published: May 2011

Enhancing column flexural capacity is the key measure in seismic capacity design to achieve strong column-weak beam failure mode and determinate the probabilistic relation between column moment magnification factor (CMMF). In the paper the effects of column moment magnification factor on seismic performance of reinforced concrete (RC) frames are evaluated to limit the occurrence probability of column-hinging failure modes within an acceptable tolerance. Monte Carlo simulation methodology is used to calculate the probability of drift demand exceeding drift capacity of two typical frame structures with consideration of major uncertainties. And fragility curves are constructed to obtain the relationship between CMMF and probability of structural damages and assess the seismic vulnerability of RC frame structures. Results show that the seismic performance of RC frame structures can be significantly enhanced by improving CMMF. The CMMF is required to be equal to or greater than 2.0 to achieve acceptable probability of exceedance of column-hinging failure mode.
SVM Model Based on the Influencing Factors Evaluation and Prediction of Ultimate Bearing Capacity of Statically-Pressured Pipe Pile
Authors: Zhao Jian Bin , Xu Chao , Shi Yong Qiang , Feng Xiao Yan
Published: May 2011

The prediction accuracy of vertical ultimate bearing capacity of statically-pressured pipe pile is difficult to ensure with traditional methods, because it is influenced by comprehensive factors, such as pile body, soil around pile and construction conditions. In this paper, a support vector machine (SVM) model based on the influencing factors importance evaluation was established to predict the vertical ultimate bearing capacity of single pile. This method would consider grey relational analysis and variable projection importance analysis as the attribute preprocessor facilities, which could determine the vertical bearing character in typical geological conditions through the analysis results of these two methods. Then, the SVM model was established with the main factors influencing ultimate bearing capacity as input to predict ultimate bearing capacity of single pile. The results showed that this method would have better precision of prediction, and the established model would have better generalization ability, which would open up a new way for the theoretical analysis of bearing characters of statically-pressured pipe pile and provide references for future relevant research.
Study on Excavation-Induced Permeability Changes in Clay Stone
Authors: Jia Shan Po , Chen Wei Zhong
Published: May 2011

The mechanical and hydraulic behavior of clay in the excavation damaged zone (EDZ) around underground repository is relevant for the assessment of the safety of geotechnical barriers. By integrating Mohr-Coulomb criterion and damage mechanics considerations, an elasto-plastic damage model is established for clay stone. Based on laboratory and in site investigations, the hydro-mechanical coupled damage model and permeability healing model is developed by the fully coupled hydro-mechanical coupled model, which can predict permeability changes and fractures self-healing in EDZ. Considering the construction of connecting gallery of radioactive waste disposal in deep clay formation in Belgium, a finite element damage model for simulating shield tunneling is proposed. The variations of damage and permeability around the tunnel with time are analyzed in detail. The proposed model is able to effectively depict the main features of hydro-mechanical behaviors of Boom clay.
Study on the Stability of Reservoir Landslide under Multiple-Factors Action
Authors: Deng Hua Feng , Guo Jing , Zhu Min , Lu Tao
Published: May 2011

According to the survey and study on geological condition, the genetic mechanism and evolving process of the reservoir landslide were analyzed at first that the landslide experienced two large slides. The first slide occurred in the J2S2 formation, it's a collapse slide with small thickness sliding mass, but made the slope on the back edge of the landslide became steeper, which created the conditions for the second slide. The second slide mainly occurred in the J2S1 formation, it's a slide that cut layer of rock stratum, which formed present landside. Then, the influencing factors on the stability of reservoir landslide were analyzed, and finite element models were created to calculate and analyze the stability of reservoir landslide under multiple-factors action. The results shows that the landslide is stable in natural conditions, and the safety factor of landslide decreases after the normal storage of reservoir, which doesn't meet the specification requirements; when considering the sudden drop in reservoir level, rainfall infiltration and other factors, the safety factor of landslide decreases further, reaching the critical stable state, and landslides may be unstable when considering earthquake. Therefore, cutting slope and reducing load were suggested, and the calculations show that the landslide trends toward stable under action of multiple-factors after treatment, which means the research achievement has a great reference value to guide engineering design and construction.
"Hollow Village" Governance Research of our Country
Authors: Ma Da Xi , Chen Zi
Published: May 2011

As the development of social economy, China's urbanization, industrialization has developed rapidly. However the development of countryside’s economy is slowly. Because of fewer land and more people, a large number of surplus population in the countryside. In order to seek better opportunities for development, many farmers pour into the city. To seek better living conditions, the farmers who are able to live in the city pour into the city. But the poor farmers began to build a new house in the periphery of the country, because the center houses of village do not suit for living. Population outsourcing formed "hollow village", and the question is more and more serious. This article has analyzed the phenomenon of “Hollow village” and some suggestions for improvement are put forward.
Study on the Relationship between Parameters of Deterioration Creep Model of Rock under Different Modeling Assumptions
Authors: Huang Ming , Liu Xin Rong
Published: May 2011

Based on the analysis to the characteristics of two kinds of rock steady creep curves, the nBurgers model that can describe the uniaxial creep properties of rock is presented. Considering the external influences on rock deformation as instantaneous elastic deterioration defined by the reduction of instantaneous elastic modulus and long-term creep deterioration defined by the reduction of long-term creep modulus, kBurgers model with deterioration is presented too. On this basis, three-dimensional model considering the Poisson’s ratio and Bulk modulus as the constant are established separately, and the relationship between their parameters is obtained. Finally, According to a calculation example, the deterioration evolution of model parameters considering water content changing under the assumption of constant bulk modulus is analyzed. In addition, the deterioration evolution equations of instantaneous elastic and long-term creep under the assumption of constant bulk modulus are obtained. It is verified that conversion relationships of model parameters are reasonable.
Interior Experimental Study on Engineering Properties of the Modified Tonhaltig Phyllite
Authors: Li Xin Ping , Lu Ya Ni , Wu Xing Hong
Published: May 2011

In view of the fact that large amounts of tonhaltig phyllite were found along the Shi-Tian expressway line, these soft rocks could not meet the roadbed filling requirements. It was necessary to improve the weathered soft rocks to satisfy the engineering demands. Interior comparative tests research on seven modified methods were carried out such as part in different proportions of cement、sand or stone bits, with soft rock of different water contents being artificial to mix and stir evenly, then unconfined compression strength of the samples at different cement quantity、different curing ages were compared; the optimum water content and and maximum dry density were determined through the compaction test; In addition, the principal effect of CBR value was analyzed. thus the best modified way was defined, the aim was to provide reference of theory and examination for further design and engineering application on weathered rock of expressway roadbed construction.
Study on the Correlation between the Stability of Slope and the Intensity of Rock Layer by Simulation Experiment
Authors: Huang Ping Lu , Chen Cong Xin
Published: May 2011

Based on similarity theory, the two geologic mechanics models with different intensity of rock layer is established. The paper introduces the design and process of the experimentation. The correlation between the stability of consequent rock slope and the intensity of rock layer is studied. Results obtained show that deformation and breakage of the consequent slope first take place at joints and crannies near the surface. The bigger the intensity of rock layer is, the steadier the slope is. The water in rock cranny can reduce the shearing strength of the slope and lead to land slide. The deformation and failure mode of the slope with low intensity of rock layer is that rock slide along the weak plane as a whole.
Design and Application of Automatic Monitoring System in Side Slope
Authors: Song Xiu Guang , Ma Zheng , Zhang Hong Bo , Wang Qian , Zhuang Pei Zhi
Published: May 2011

The field monitoring of dangerous landslide is an important measure for guaranteeing its safety, especially when surrounded by large-scale construction. The landslide located nearby a reservoir in Shandong province. To guarantee construction safety, we adopted the automatic monitoring method for monitoring surface displacement and the internal soil pressure. The whole system uses solar power to provide energy and uses GPRS to transfer data. This system not only can provide reliable information for project construction, but also promote the application of environmentally friendly, low carbon in the monitoring field of civil engineering.
Finite-Difference Method Appliance to the Computation of Ground Additional Stress and Settlement of Storage Tank
Authors: Cheng Xu Dong , Peng Wen Shan , Liu Lei
Published: May 2011

This paper adopts the Finite-difference method to research the distribution of ground additional stress and distortion in differently isotropic and non-isotropic foundation conditions, and uses the Finite-difference method to compare with the Finite-element method and the three-dimensional settlement method used by the code. Through comparative analysis, the reliability and superiority of Finite-difference method used for calculating ground additional stress and settlement are justified.
The Effect of Heterogeneity and Element Sizes on Rock Mechanics Properties
Authors: Lu Hai Jun , Cai Guang Hua , He Li , Hu Zhu Yun , Li Jiang Shan
Published: May 2011

Based on the analysis of the experiment, a statistical damage model can be established according with Weibull distribution from the basic characteristics of rocks, the statistic theory of heterogeneity and the microscopic principles of damages, analyze the constitutive relationship of rocks through the stress-strain relationship, heterogeneity, and the element sizes. According to the analysis of rock strength and failure models in numerical simulation, it is acquired the influence of heterogeneity and element sizes on rock mechanics properties. The results of numerical simulation provide a new way for the study of the medium macro behavior on the deformations and fractures.
Study on Stability for Intersection of Deep Soft Rock Roadway
Authors: Li Zhan Jin , Zhang Yang , Zhao Xue Li
Published: May 2011

With the depth increasing continuously, more complicated of geological conditions, will make intersection in deep soft rock roadway is very difficult to support. In order to solve the intersection problem of difficult to support, combined with the third levels of the Fifth Coal Mine of Hemei, the coupling supporting design—anchor-mesh-cable + truss to control stability of crossing point—is proposed. Based software of FLAC3D, simulate the program applicable in deep soft rock roadway intersection. Application results show that the coupling support technology of anchor-mesh-cable + truss can effectively control the deformation of intersection in deep soft rock roadway.
Study on Dynamic Response of Hollow Pile Using the Method of Composite Stiffness Principle and Biparameter
Authors: Zhang Yong Mou , Yang Min , Yan Qiang Gang
Published: May 2011

The method of composite stiffness principle and biparameter for laterally loaded pile was used in this paper to calculate the amplitude of deflection and rotation of pile on the ground when the vibration frequency of dynamic load is equal to or close to the natural frequency of pile, i.e. when the pile is in the state of resonance. And the amplitude of the maximum bending moment and its location was also calculated. Then the finite difference method which is simple in principle and easy to program was used to calculate the displacement, soil side resistance and internal forces of pile under horizontal dynamic load. By choosing reasonable parameters, rotation, displacement, and the maximum bending moment of hollow concrete pile and solid pile under the same dynamic loads at pile top in the same geological conditions were calculated respectively. On this basis, the performance differences between hollow pile and solid pile were analyzed. Some advantages of hollow pile were obtained. This research provides a theoretical guidance for the using of hollow pile in engineering.
Generalized Gradient-Dependent Plasticy Theory
Authors: Zhao Bing , Li Ning , Song Yi , Yan Xiao Qiang
Published: May 2011

Based on the Generalized Plastic Mechanics (GPM) and strain gradient-dependence of yield surfaces, the differential expressions of the volumetric and shear plastic strains are constructed, then the Generalized Gradient-dependent Plastic Mechanics (GGPM) is established to describe the strain localization characteristics and the basic mechanics characteristics of geo-materials. In order to discretize the controlling equations and the boundary conditions of analyses filed, an increment functional in which the displacement and plastic multipliers are independent variables was constructed to build up the variational principle of GGPM. Both the displacement and the plastical factor are discretized in space. A set of non-linear equations taking the displacements and the plastic factors of nodes as the unknown variables are obtained to solve the new proposed mechanic model. The boundary condition and the increment algorithm are also given. The numerical examples indicate that: (1) when strain localization appears,the plastic shear strain and the plastic volumetric strain mainly concentrate in localization band; (2) the mesh- dependency does not appear any more when the size of mesh changes; (3) when the parameters reflecting localization increase,the width of the strain localization band will be wider obviously.
At-Rest Earth Pressure Coefficient from Hypoelastic Model
Authors: Shang Xiang Yu , Zhou Guo Qing
Published: May 2011

At-rest earth pressure codfficient,K0,is very important in geotechnical engineering design and finite element analysis. At present, it’s treated as a constant usually for given soil in FEM analysis. However recent test results indicate that K0of both clay and sand varies with pressure increasing nonlinearly. It’s shown that Duncan-Chang model, a kind of hypoelastic model widely used, can reproduce K0varying with pressure. The calculating procedure of K0derived from Duncan-Chang’s E-B model is proposed, and then influence of model parameters on calculated K0is explored. Studies show that cohesionless soil’s calculated K0decreases with pressure increasing, while cohesive soil’s calculated K0increases with pressure increasing. Three of the seven model parameters, m, Kband Rf, have a positive correlation with calculated K0, and there is a negative correlation between the residual parameters and calculated K0.The influence of seven model parameters on the calculated K0decreases gradually in the following order: m ,n, Rf, φ, c, K, Kb.
Two-Dimensional Numerical Simulation Analysis of the Diaphragm Wall Earth Pressure and Deformation Used the Cover Reverse Construction Excavation Method
Authors: Guo Hong Bo , Ding Ke Sheng , Zhang Yi Jia , Li Xu
Published: May 2011

The cover reverse construction excavation is one of the important construction methods which is used in digging extra-deep foundation system of underground continuous wall supporting. The earth pressure distribution and deformation is distinct from different construction methods. Even if the Construction methods and computer program is homogeneous, the earth pressure and deformation of the calculated showed various results because of different test parameters and different constitutive models, Through the application of practical engineering, The appropriate calculation parameters and constitutive model are found out in Abaqus program which is suitable for earth pressure and deformation of the diaphragm wall in the soft soil area.
Research on Shear Creep Property of Soft Rock in Dam Foundation
Authors: Wang Yu , Deng Hua Feng , Lu Tao , Zhao Zong Yong
Published: May 2011

Creep characteristic is one of the most important mechanical characteristics of rock. It controls the stability of rock engineering. Under step load conditon, the shear creep test of argillaceous siltstone which was collected in dam foundation is performed by using the RMT150c rock and soil mechanics testing machine. The shear creep curves under different normal stresses show that the argillaceous siltstone is very significant in creep, which should be considered in the stability analysis of dam foundation. According to the analysis of experimental results, the long-term shear strength parameters are determined to provide reference for engineering survey and design.
Evaluation of Aseismic Stability of Gangue Slope Based on Nonlinear Mohr-Coulomb Failure Criterion
Authors: Zhao Gang Fei , Guo Hui Zhi , Lin Yong Liang , Duan Wei
Published: May 2011

It is extremely important to establish hazard maps showing earthquake-induced displacements, safety factors and probabilities of failure. The combination of pseudo-static method and displacement-based method is commonly used to evaluate the stability of gangue slope. Conventional calculations are formulated in terms of a linear Mohr–Coulomb (MC) failure criterion. However, experimental data shows that the strength envelops of almost all types of rocks are nonlinear over the wide range of normal stresses. In this paper, the nonlinear failure criterion is introduced. The resulting safety factor and permanent displacement are discussed and demonstrated using several real earthquake records.
Stability Analysis of the Stiffened Plate with Rids under the Longitudinal Loads
Authors: Zhang Yu
Published: May 2011

The stiffened plate with rids was considered as a whole structure. Using energy method the stability of stiffened plates with rids under the longitudinal forces was analyzed. Calculating the potential energy of deformation of plate and that of rids and the work done by the neutral plane forces of plate when the plates were buckled, the formulas of critical loads of the stiffened plate with rids under longitudinal forces were derived from the minimum condition of total potential energy. Using the formulas in this paper engineers can easily calculate the critical loads of the stiffened plate with rids under the boundary conditions: the opposite sides are fixed and the other opposite sides are simply supported, four sides are simply supported. The formula of critical loads of the stiffened plate with rids under other boundary conditions can be derived using the method in this paper.
3D FEM Parallel Computation Geostress Neural Network Analysis Based on Deep Comp 1800 Cluster System
Authors: Chen Zhi Min , Zhao De An
Published: May 2011

The substantial difficulties are encountered as the huge computation of complex three-dimensional finite element model. Network parallel computing is one of the most compelling topics at the forefront in the current field of parallel computing, the size and the speed of structural analysis can be increased by the combination of both, so that large and complex three-dimensional finite element calculation can be carried out smoothly. According to Wushaoling tunnel, three-dimensional finite element model is established and implement under the support of the finite element parallel computing environment of Deep Comp 1800 cluster system based on the analysis of neural network. The realization of 3D geostress analysis is also depend on the artificial neural network computation program ANNBP and MEBAC, which is an interface program connecting ANNBP and ANSYS. The results show that the computation efficiency is highly improved by the Deep Comp 1800cluster system, the distribution of the initial geostress field is compacted significantly by the faults and there is a vertical extrusion characteristic with the tunnel at the fault zone.
Research on Creep Property of Cement Grouted Joint
Authors: Sun Fu Ting , She Cheng Xue , Li Kun
Published: May 2011

The creep property of cement grouted joint is studied based on creep test and theoretical analysis. Firstly, the multi-stage shear creep test under constant normal stress, joint roughness and cement filled thickness is carried out to obtain the creep deformation. Then the conventional linear Nishihara model is used to fit the test results. Due to the big deviation of the theoretical results from the test, the instantaneous elastic shear stiffnesses under different loading stages are calculated. It is found that they vary with the shear stress. The reasons for the nonlinearity are analyzed. Finally the parameters of the Nishihara model are modified to be nonlinear and fit with the test results showing good coincidence between them. These researches release the creep property of the cement grouted joint, and will provide a good basis for further research considering more influencing factors such as normal stress, joint roughness and cement filled thickness.
Reliability-Based Stability Analysis of Foundation Pit Supported by Micro-Pile Composite Soil Nailing
Authors: Zhao Yan Lin , An Wei Guang
Published: May 2011

Considering the co-action of micro-pile and soil nailing, the state equation of limit equilibrium and the performance function of inner global stability of foundation pit supported by the micro-pile composite soil nailing is set up with the slope limit equilibrium theory and the circular sliding slice method. The calculating model of sliding surface for inner global stability of foundation pit is established with the geometry controlling method and the optimization searching of the most dangerous sliding surface is achieved. Then with the shear strength indexes of soil as random variables, the partial derivatives of the performance function to all random variables is deduced and the reliability index of inner global stability of foundation pit supported by micro-pile composite soil nailing is calculated with the design checking point method. Finally, the effects of coefficients of variability of the random variables on reliability index are analyzed.
Simplified Modeling of Ground Motion on Liquefied Sites under Seismic Loading
Authors: Chen Long Wei , Yuan Xiao Ming , Sun Rui
Published: May 2011

Using a double-layer horizontal strata model, a simplified time-history analytical method which considers liquefiable layer existence is proposed for calculating ground motion acceleration and displacement. Solutions in frequency and time domains under arbitrary loading are given. By the cycle-by-cycle method, the calculating results of ground acceleration and displacement time histories under arbitrary loading are presented. Adopting a proper pore-water pressure ratio incremental model, shear modulus of the liquefiable layer is modified cycle by cycle that the nonlinearity of the liquefiable layer induced by soil liquefying is proximately simulated. Through numerical analysis, ground displacement on liquefied sites is much larger than that on non-liquefied sites during liquefaction process. Before initial liquefaction, ground displacement and acceleration on liquefied sites are obviously higher than those on non-liquefied sites. After initial liquefaction, ground acceleration remarkably decreased but displacement remains much larger than that on non-liquefied sites. Normalized acceleration response spectra are calculated. It shows that the low period components on liquefied sites are lower than those on non-liquefied sites, but long period components are higher than those on non-liquefied sites.