水入渗前后重塑红黏土抗剪强度特性研究

基于不固结不排水三轴压缩试验，探究蒸馏水入渗前后不同干密度重塑红黏土的应力-应变关系以及抗剪强度变化，并结合电镜扫描试验和X射线荧光分析试验从微观结构及矿物成分变化角度来分析水入渗对不同干密度重塑红黏土抗剪强度的影响机理。研究结果表明:重塑红黏土应力-应变关系随干密度的增大由应变硬化型逐渐变为应变软化型，水入渗后重塑红黏土达到破坏点时的轴向应变较大；黏聚力随干密度的增大呈指数变化，内摩擦角随干密度增加呈线性变化；水入渗前后土样抗剪强度变化说明水入渗对高干密度重塑红黏土的影响较为明显，微观结构和矿物元素成分变化则说明高干密度可有效保持土样内部结构和减少矿物元素成分的流失。

Study on Shear Strength Characteristics of Remoulded Red Clay before and after Water Infiltration

Based on unconsolidated undrained triaxial compression test, this paper explored the stress-strain relation of the remoulded red clay with different dry density before and after infiltration of distilled water and the change of the shear strength thereof; then combined with electronic microscopy scanning test and X-ray fluorescence analysis test, studied from the microscopic structure and the change of mineral composition the mechanism affecting the shear strength of such clay under water infiltration. The study result shows that, the stress-strain relation of remoulded red clay will change with the increase of dry density from strain hardening type to strain softening type gradually and, after water infiltration, the axial strain is larger when the remoulded red clay reaches the failure point; as the dry density increases, the cohesion presents an exponential change, and the internal frictional angle a linear change; the shear strength change of soil specimen before and after water infiltration demonstrates that water infiltration has significant effect on the remoulded red clay with high dry density, while the microscopic structure and the change of mineral composition demonstrates that high dry density is helpful to maintain the soil specimen’s internal structure and reduce the loss of mineral composition.