不同含水率下广州地区残积土强度特性研究  

Study on Influence of Different Water Content on Strength Property of Residual Soil in Guangzhou Area

作　　者：许丹[1] XU Dan(China Railway 11^(th)Bureau Group Co.Ltd.,Wuhan Hubei 430061,China)

机构地区：[1]中铁十一局集团有限公司,湖北武汉430061

出　　处：《铁道建筑技术》2023年第2期58-62,共5页Railway Construction Technology

基　　金：中国铁建股份有限公司科技研究开发计划项目(19-B17)。

摘　　要：花岗岩残积土具有遇水软化崩解的特性,其力学强度极易受含水率影响。本文以广州某基坑残积土重塑样为研究对象,进行不同含水率下三轴固结不排水剪切试验,探究不同含水率条件下对非饱和残积土强度特性的影响规律,并运用最小二乘法推导出土体在不同含水率下的抗剪强度包络线表达式。试验结果表明:在含水率为20%~41.6%时,黏聚力随含水率增大而减小,内摩擦角变化幅度则很小,围压在一定程度上可以提高土体的抗剪强度;残积土剪切过程其应力-应变曲线无明显峰值,主要呈现出应变硬化的趋势。Granite residual soil has the characteristics of softening and disintegrating when encountering water, whose mechanical strength is greatly affected by water content. This study utilizes the remolded residual soil of a deep foundation pit in Guangzhou to carry out the triaxial consolidation undrained shear test, exploring the influence of different water content on strength property of unsaturated residual soil, and deducing the expression of shear strength envelope of soil under different water content by using the least square method. The results show that when the water content is 20% to 41.6%, the cohesion decreases with the increase of water content, while the water content has little effect on the internal friction angle. Confining pressure can improve the shear strength of soil to a certain extent. There is no obvious peak in the stress-strain curve of residual soil during the shearing process, which mainly shows the trend of strain hardening.

关 键 词：残积土 含水率 抗剪强度 应力应变曲线 室内试验 

分 类 号：TU441[建筑科学—岩土工程]