长春季冻区重塑粉质黏土抗剪强度影响因素研究

Research on influencing factors of shear strength for remodeling silty clay in seasonal frozen region of Changchun

本文以取自长春市宽城区6 m深处土壤(典型粉质黏土)为研究对象,制备4种不同含水率、不同干密度的16组土样,对其进行不同法向应力下的重塑土直剪试验.试验结果表明,干密度一定时,相同应力下重塑粉质黏土的抗剪强度随含水率的升高而明显下降,而含水率一定时,提升干密度,抗剪强度将显著增大.不同法向应力下,随含水率增加,抗剪强度呈单调递减,随干密度增加而上升.含水率的提升将显著降低内摩擦角,而内摩擦角的大小与干密度的变化并无明显规律,含水率一定时,若增加干密度,内摩擦角的变化范围并不很大.此外,扰动粉质黏土的黏聚力与干密度呈单调递增,而与含水率呈递减.

The object of study is the soil(remolded silty clay)in depth of 6 m selected from Kuancheng District in Changchun.The study contents include preparing 16 soil samples with 4 kinds of different moisture contents and 4 kinds of different dry densities,and test them under different normal stresses and the condition of direct shearing in remolded silty clay.The test result shows that when the dry density is constant,the shear strength of the remolded silty clay under the same stress will decrease significantly with the increase of moisture content.However,when the moisture content is constant,the dry density will be increase and the shear strength will be significantly increase too.The increased moisture content will make the internal friction angle decrease,but the internal friction angle is no obvious change with the change of dry density.When the moisture content is constant,if the dry density is increased,the changes of internal friction angle will be small.In addition,the cohesive force and dry density of the disturb silty clay are in a monotonously increasing,but in a decreasing with the moisture content.