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
A novel soil strength criterion is proposed based on the shear stress ratio on a new spatially mobilized plane, where the cube root of principal stresses is constant. The strength failure surface depicted in the princ...A novel soil strength criterion is proposed based on the shear stress ratio on a new spatially mobilized plane, where the cube root of principal stresses is constant. The strength failure surface depicted in the principal stress space by this criterion was smoothly conical, with a curved triangle shape on the octahedral plane. A comparative analysis of the strength failure surfaces of the Mohr-Coulomb (M-C), the Drucker-Prager (D-P), the Matsuoka-Nakai (M-N), the Lade-Duncan (L-D), the new criteria, and the shear strength laws of different criteria with parameter b on the π plane showed that the L-D criterion and the new spatially mobilized plane strength criterion were comparable, which revealed the physical essence of the L-D criterion. Comparing the new strength criterion with the measured results of true triaxial tests of 4 kinds of intact loess under conditions of consolidation and drain, the strength law of loess could be described by the new strength criterion under complex stress conditions, and the rationality and reliability of the strength criterion were verified by the correspondence between the criterion and experimental values.展开更多
There are many methods to construct true triaxial strength criteria for rocks.Jaiswal and Shrivastva(2012)proposed a strength criterion,named J–S criterion,in the deviatoric plane,which provides nearly the same misft...There are many methods to construct true triaxial strength criteria for rocks.Jaiswal and Shrivastva(2012)proposed a strength criterion,named J–S criterion,in the deviatoric plane,which provides nearly the same misfts for true triaxial test data as the exponential criterion.It is diffcult to calculate the strength at given2and3using the J–S criterion,and the multiple solutions to the nonlinear equation may induce confusion and mistake.Strength envelopes in deviatoric planes are not geometric similar;therefore,true triaxial test data cannot be grouped in the mean stress to check strength criteria in the deviatoric plane.展开更多
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.
文摘A novel soil strength criterion is proposed based on the shear stress ratio on a new spatially mobilized plane, where the cube root of principal stresses is constant. The strength failure surface depicted in the principal stress space by this criterion was smoothly conical, with a curved triangle shape on the octahedral plane. A comparative analysis of the strength failure surfaces of the Mohr-Coulomb (M-C), the Drucker-Prager (D-P), the Matsuoka-Nakai (M-N), the Lade-Duncan (L-D), the new criteria, and the shear strength laws of different criteria with parameter b on the π plane showed that the L-D criterion and the new spatially mobilized plane strength criterion were comparable, which revealed the physical essence of the L-D criterion. Comparing the new strength criterion with the measured results of true triaxial tests of 4 kinds of intact loess under conditions of consolidation and drain, the strength law of loess could be described by the new strength criterion under complex stress conditions, and the rationality and reliability of the strength criterion were verified by the correspondence between the criterion and experimental values.
文摘There are many methods to construct true triaxial strength criteria for rocks.Jaiswal and Shrivastva(2012)proposed a strength criterion,named J–S criterion,in the deviatoric plane,which provides nearly the same misfts for true triaxial test data as the exponential criterion.It is diffcult to calculate the strength at given2and3using the J–S criterion,and the multiple solutions to the nonlinear equation may induce confusion and mistake.Strength envelopes in deviatoric planes are not geometric similar;therefore,true triaxial test data cannot be grouped in the mean stress to check strength criteria in the deviatoric plane.
