花岗岩残积土垂直层次抗剪强度变异性研究

花岗岩残积土广泛分布于我国南方,它具有特殊的土壤力学性质,研究花岗岩残积土垂直层次抗剪强度变异性及其影响因素对于指导工程施工及解释崩岗发生演变具有十分重要的意义。对花岗岩残积土进行多点采样,通过对花岗岩残积土不同层次的土壤进行基本性质测定,研究了土体在垂直层面上抗剪强度的变异特性及影响因素。研究发现:花岗岩残积土土体垂直层次之间的抗剪强度差异较大,这种差异主要体现在内摩擦角的变化上;影响花岗岩残积土抗剪强度指标的主要因素为水分含量以及砂粒含量;同时考虑水份和砂粒含量两项因素时,一定含水率范围内,抗剪强度随含水率的降低、砂粒含量的增多而增大,凝聚力总体随含水率降低而升高,随砂粒含量的增大而减小,内摩擦角总体随含水率降低而升高,随砂粒含量的增多而增大。

Study on spatial variability of shear strength in different vertical layers of granite residual soil

Granite residual soil, characterized with special soil mechanical properties, is widely distributed in the south of China. Investigation of the spatial variability of the shear strength of granite residual soil in vertical profile and its influential factors can provide significant values for guiding excavation construction and explaining the occurrence of collapsing hill. The basic characteristics of the granite residual soil sampled at different elevations of vertical profiles were tested and the shear strength of vertical profile and its variability were studied. It is found that there is a significant difference in vertical shear strength at different levels, which is especially reflected by the variation of the internal friction angle; soil moisture and sand content play a prominent role in granite shear strength. When soil moisture content and sandy particle content are both considered as variables, the shear strength increases as the soil moisture declines and sand content increases; the soil cohesion increases with the decrease of soil moisture content, but decreases with the rise of sand content; the internal friction angle demonstrates an upward trend with the decrease of water content and increase of sand content.