非饱和残坡积土强度随含水量变化试验研究

Experimental Studies of the Strength Variation of Unsaturated Residual Soil with Different Water Contents

直接研究非饱和土的强度随含水量的变化,建立引入含水量的强度公式,具有重要的实用价值.在普通三轴仪上进行非饱和残坡积土的强度试验,试验结果表明,非饱和残坡积土的抗剪强度随着含水量的增大而明显减小,这说明水分对强度的影响剧烈.引入参数峰残应力比对非饱和残坡积土的应变软化特性进行了量化分析,发现最佳含水量为应力应变曲线从软化转变为硬化的临界含水量,且凝聚力c值随含水量的增加呈指数衰减,内摩擦角φ值随含水量的增加呈线性衰减.在此基础上提出非饱和残坡积土总应力强度公式,公式运用简单便捷,可为工程实际应用提供参考.

It is of significant practical value to investigate the strength variation of unsaturated residual soil with different water contents,and establish the computational formulae between them.In the general tri-axial instrument,strength tests were conducted on unsaturated residual soil.The results indicated that the shear strength of unsaturated residual soil decreased significantly with the increase of the water content,which demonstrated that water contents had considerable influence on strength.Quantitative analysis of the strain softening characteristics of unsaturated residual soil was done by adopting peak-residual stress ratio.It was found that the optimum water content equaled the critical water content where stress-strain curve was transformed from softening to hardening,the value of c decayed exponentially with the increase of water content,and the value of φ decayed linearly.Based on these results,the integral stress strength formula of unsaturated residual soil was proposed,which can be applied in practice and provide reference in practical situations.