负温养护下水泥稳定粉质黏土的剪切特性研究

Shear Characteristics of Cement-Stabilized Silty Clay under Negative Temperature Curing

水泥稳定土广泛应用于寒区岩土的改良,明晰负温养护条件下水泥稳定土剪切强度的主控因素及变化机制对于寒区工程安全运维具有重要意义。本文开展了不同养护温度、水泥含量、含水率、龄期条件下水泥稳定粉质黏土的剪切特性试验,分析了负温养护下水泥稳定粉质粘土剪切强度的变化规律。结果表明:负温养护下水泥稳定土的抗剪强度小于常规养护下水泥稳定土的抗剪强度;不同养护温度下水泥稳定土的剪切破坏形态表现出不同程度的脆性效应;抗剪强度随着水泥含量的增加而增大,初始含水率为16%~20%时对水泥稳定土强度增长最为有利;水泥稳定土的黏聚力随着水泥含量的增加而增大,随着初始含水率的增加先增大后减小;内摩擦角随着水泥含量及初始含水率的增加也呈现先增大后减小的趋势。

Cement-stabilized soil is widely-used to improve mechanical properties of soils in cold regions.For the safety operation and maintenance of geotechnical engineering,it is important to clarify the main control factors of shear strength and the change mechanism of shear characteristics for cement-stabilized soil cured at negative temperatures.In this paper,the shear characteristics of cement-stabilized silty clay were tested under different curing temperatures,cement content,initial water content,and curing age.The influencing factors and variation rules of the shear strength for cement-stabilized silty clay under negative curing temperature were analyzed.The test results show that the shear strength of cement-stabilized soil under negative curing temperature is less than that under positive curing temperature.The pore characteristics of cement-stabilized soil are significantly different under different curing temperatures,which makes the shear failure morphology of cement-stabilized soil shows different degrees of brittleness effect.Besides,initial cement content and initial water content significantly affect the shear strength of cement-stabilized soils,and its shear strength increases with the cement content raised,the optimal initial water content of 16%~20%is the most favorable for the strength growth with cement-stabilized soil.Additionally,the cohesion of cement-stabilized soil increases with the cement content,and firstly increases and then decreases with the initial water content.With the increase of cement content and initial water content,the internal friction angle also firstly increases and then decreases.