Deformation characteristics of coarse-grained soil with various gradations
来源期刊：中南大学学报(英文版)2014年第6期
论文作者：MENG Fei(孟飞) ZHANG Jia-sheng(张家生) 陈晓斌 WANG Qi-yun(王启云)
文章页码：2469 - 2476
Key words：coarse-grained soil; volumetric strain; triaxial test; dilatancy; gradation
Abstract: By using large scale triaxial shearing apparatus, consolidated-drained shear tests were conducted on coarse-grained soil with different gradations. In order to describe their deformation rules, three main characteristics of tangent Poisson ratio curves were summarized and the reason was revealed by dividing the movement of soil particles into two kinds: the movement of fine particles and the movement of coarse particles. Then, a volumetric strain expression and a tangent Poisson ratio expression were put forward, and two defects of widely used Duncan-Chang model were fixed. Results calculated from them agree well with test results. There are three parameters, namely L, G and F, in this new model. Parameter L reflects the dilatancy of a specimen and L=4 can be used as a criterion to estimate whether a certain kind of soil has dilatancy quality or not. Parameters G and F relate to the initial slope of tangent Poisson ratio curves, and G=F=0 indicates a special situation which happens in dense granular material of the same diameter. Influences of various gradations on volume deformation are mainly reflected in parameter L which is smaller when there are more gravels in specimens.
MENG Fei(孟飞)1, ZHANG Jia-sheng(张家生)1, CHEN Xiao-bin(陈晓斌)1, WANG Qi-yun(王启云)2
(1. School of Civil Engineering, Central South University, Changsha 410075, China;
2. College of Civil Engineering, Fujian University of Technology, Fuzhou 350108, China)
Abstract:By using large scale triaxial shearing apparatus, consolidated-drained shear tests were conducted on coarse-grained soil with different gradations. In order to describe their deformation rules, three main characteristics of tangent Poisson ratio curves were summarized and the reason was revealed by dividing the movement of soil particles into two kinds: the movement of fine particles and the movement of coarse particles. Then, a volumetric strain expression and a tangent Poisson ratio expression were put forward, and two defects of widely used Duncan-Chang model were fixed. Results calculated from them agree well with test results. There are three parameters, namely L, G and F, in this new model. Parameter L reflects the dilatancy of a specimen and L=4 can be used as a criterion to estimate whether a certain kind of soil has dilatancy quality or not. Parameters G and F relate to the initial slope of tangent Poisson ratio curves, and G=F=0 indicates a special situation which happens in dense granular material of the same diameter. Influences of various gradations on volume deformation are mainly reflected in parameter L which is smaller when there are more gravels in specimens.
Key words:coarse-grained soil; volumetric strain; triaxial test; dilatancy; gradation
