The capability of piles to withstand horizontal loads is a major design issue.The current research work aims to investigate numerically the responses of laterally loaded piles at working load employing the concept of ...The capability of piles to withstand horizontal loads is a major design issue.The current research work aims to investigate numerically the responses of laterally loaded piles at working load employing the concept of a beam-on-Winkler-foundation model.The governing differential equation for a laterally loaded pile on elastic subgrade is derived.Based on LegendreGalerkin method and Runge-Kutta formulas of order four and five,the flexural equation of long piles embedded in homogeneous sandy soils with modulus of subgrade reaction linearly variable with depth is solved for both free-and fixed-headed piles.Mathematica,as one of the world’s leading computational software,was employed for the implementation of solutions.The proposed numerical techniques provide the responses for the entire pile length under the applied lateral load.The utilized numerical approaches are validated against experimental and analytical results of previously published works showing a more accurate estimation of the response of laterally loaded piles.Therefore,the proposed approaches can maintain both mathematical simplicity and comparable accuracy with the experimental results.展开更多
The stress vector-based constitutive model for cohesionless soil, proposed by SHI Hong-yan et al., was applied to analyze the deformation behaviors of materials subjected to various stress paths. The result of analysi...The stress vector-based constitutive model for cohesionless soil, proposed by SHI Hong-yan et al., was applied to analyze the deformation behaviors of materials subjected to various stress paths. The result of analysis shows that the constitutive model can capture well the main deformation behavior of cohesionless soil, such as stress-strain nonlinearity, hardening property, dilatancy, stress path dependency, non-coaxiality between the principal stress and the principal strain increment directions, and the coupling of mean effective and deviatoric stress with deformation. In addition, the model can also take into account the rotation of principal stress axes and the influence of intermediate principal stress on deformation and strength of soil simultaneously. The excellent agreement between the predicted and measured behavior indicates the comprehensive applicability of the model.展开更多
On the basis of the sufficient consideration of vectorial characteristics of stress, a new nonlinear constitutive model for cohesionless soil under plane strain and 3-D conditions was presented in a way that the actio...On the basis of the sufficient consideration of vectorial characteristics of stress, a new nonlinear constitutive model for cohesionless soil under plane strain and 3-D conditions was presented in a way that the action effects of stress vector are decomposed into the action effect of mean effective stress and that of the stress ratio vector (ratio of deviatoric stress vector to mean effective stress). The constitutive model can take account of the influence of both numerical and directional changes of stress vector on deformation of soil simultaneously, and is applicable of both static and dynamic loading.展开更多
In order to investigate the influence of intermediate principal stress on the stress-strain and strength behaviour of a coarse-grained soil,a series of true triaxial tests were performed.The tests were conducted in a ...In order to investigate the influence of intermediate principal stress on the stress-strain and strength behaviour of a coarse-grained soil,a series of true triaxial tests were performed.The tests were conducted in a recently developed true triaxial apparatus with constant minor principal stressσ3 and constant value of intermediate principal stress ratio b=(σ2-σ3) /(σ1-σ3) (σ1 is the vertical stress,andσ2 is the horizontal stress) .It is found that the intermediate principal strain,ε2,increases from negative to positive value with the increase of parameter b from zero to unity under a constant minor principal stress.The minor principal strain,ε3,is always negative.This implies that the specimen exhibits an evident anisotropy.The relationship between b and friction angle obtained from the tests is different from that predicted by LADE-DUNCAN and MATSUOKA-NAKAI criteria.Based on the test results,an empirical equation of g(b) that is the shape function of the failure surface onπ-plane was presented.The proposed equation is verified to be reasonable by comparing the predicted results using the equation with true triaxial test results of soils,such as coarse-grained soils in this study,sands and gravels in other studies.展开更多
文摘The capability of piles to withstand horizontal loads is a major design issue.The current research work aims to investigate numerically the responses of laterally loaded piles at working load employing the concept of a beam-on-Winkler-foundation model.The governing differential equation for a laterally loaded pile on elastic subgrade is derived.Based on LegendreGalerkin method and Runge-Kutta formulas of order four and five,the flexural equation of long piles embedded in homogeneous sandy soils with modulus of subgrade reaction linearly variable with depth is solved for both free-and fixed-headed piles.Mathematica,as one of the world’s leading computational software,was employed for the implementation of solutions.The proposed numerical techniques provide the responses for the entire pile length under the applied lateral load.The utilized numerical approaches are validated against experimental and analytical results of previously published works showing a more accurate estimation of the response of laterally loaded piles.Therefore,the proposed approaches can maintain both mathematical simplicity and comparable accuracy with the experimental results.
文摘The stress vector-based constitutive model for cohesionless soil, proposed by SHI Hong-yan et al., was applied to analyze the deformation behaviors of materials subjected to various stress paths. The result of analysis shows that the constitutive model can capture well the main deformation behavior of cohesionless soil, such as stress-strain nonlinearity, hardening property, dilatancy, stress path dependency, non-coaxiality between the principal stress and the principal strain increment directions, and the coupling of mean effective and deviatoric stress with deformation. In addition, the model can also take into account the rotation of principal stress axes and the influence of intermediate principal stress on deformation and strength of soil simultaneously. The excellent agreement between the predicted and measured behavior indicates the comprehensive applicability of the model.
文摘On the basis of the sufficient consideration of vectorial characteristics of stress, a new nonlinear constitutive model for cohesionless soil under plane strain and 3-D conditions was presented in a way that the action effects of stress vector are decomposed into the action effect of mean effective stress and that of the stress ratio vector (ratio of deviatoric stress vector to mean effective stress). The constitutive model can take account of the influence of both numerical and directional changes of stress vector on deformation of soil simultaneously, and is applicable of both static and dynamic loading.
文摘利用改进的渗透装置试验研究了细颗粒(0.075~1 mm)含量相同时骨架颗粒组成含量不同对散粒土的管涌发生临界条件以及颗粒侵蚀流失规律的影响,结果表明:不同颗粒级配的试样在管涌发生前,水力梯度与渗流速度呈线性关系,基本符合达西定律;骨架颗粒1~2、2~3、3~5 mm 3个粒径段对管涌发展起到了阻碍作用,其中1~2 mm粒径段颗粒对管涌孔隙的堵塞作用强于另外两个粒径段颗粒;对于不同级配的骨架颗粒,其不均匀系数越大,试样的下限临界水力梯度值就越大,细颗粒越不易起动,发生管涌的时间越晚,而不同级配的骨架颗粒对试样的上限临界水力梯度影响较小。
基金Project(50639050) supported by the National Natural Science Foundation of China and Er-Tan Hydraulicpower Limited CompanyProject(50579014) supported by the National Natural Science Foundation of China+3 种基金Project(09KJD560003) supported by the Natural Science Foundation of Jiangsu Higher Education Institutions of ChinaProject(BK2007582) supported by Jiangsu Provincial Natural Science Foundation of ChinaProject(20070294002) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of ChinaProject(GH200904) supported by Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,China
文摘In order to investigate the influence of intermediate principal stress on the stress-strain and strength behaviour of a coarse-grained soil,a series of true triaxial tests were performed.The tests were conducted in a recently developed true triaxial apparatus with constant minor principal stressσ3 and constant value of intermediate principal stress ratio b=(σ2-σ3) /(σ1-σ3) (σ1 is the vertical stress,andσ2 is the horizontal stress) .It is found that the intermediate principal strain,ε2,increases from negative to positive value with the increase of parameter b from zero to unity under a constant minor principal stress.The minor principal strain,ε3,is always negative.This implies that the specimen exhibits an evident anisotropy.The relationship between b and friction angle obtained from the tests is different from that predicted by LADE-DUNCAN and MATSUOKA-NAKAI criteria.Based on the test results,an empirical equation of g(b) that is the shape function of the failure surface onπ-plane was presented.The proposed equation is verified to be reasonable by comparing the predicted results using the equation with true triaxial test results of soils,such as coarse-grained soils in this study,sands and gravels in other studies.
