含水率对花岗岩边坡风化层界面剪切特性的影响

Effect of Water Content on Weathered Layer Interface Shear Characteristics of Granite Slope

为了研究含水率变化对成层状风化花岗岩边坡稳定性的影响,进行了一系列单调直剪试验。设置四种含水率(13%、17%、21%和25%)和三种干密度(ρ_(d1)、ρ_(d2)、ρ_(d3)),分析不同干密度下含水率对花岗岩残积土-全风化花岗岩界面剪切特性的影响。试验结果表明:在低含水率、高干密度和低竖向应力下,界面剪应力易发生剪切软化,反之,更易发生剪切硬化;含水率越高,最大剪胀量越小,且干密度越大,最大剪胀量受含水率变化的影响越小;含水率升高会大幅降低界面抗剪强度,且干密度越大、竖向应力越小,界面抗剪强度随含水率的变化率越大。

In order to study the effect of rainfall on the stability of weathered granite layered slope,a series of monotone direct shear tests were carried out.Four kinds of water content(13%,17%,21% and 25%)and three kinds of dry density were set to analyze the effect of water content on the shear characteristics of granite residual soil and completely weathered granite interface shear behaviour.The experimental results indicate that the shear stress of the interface is prone to shear softening under low water content,high dry density and low normal stress,and otherwise,shear hardening is more likely to occur.The maximum dilatancy decreases as the increase of water content.And the larger the dry density is,the less the effect of water content on the maximum dilatancy is.The increase of water content significantly reduces the interfacial shear strength,and the greater the dry density,the smaller the normal stress,and the greater the attenuation coefficient of interfacial shear strength.