非饱和膨胀土抗剪强度的三轴试验研究

Experimental Study of Triaxial Test of Unsaturated Expansive Soil Shear Strength

基于非饱和三轴试验系统,对不同含水量情况下南宁非饱和膨胀土的强度特性进行研究。研究表明:在定围压下,低含水量时的应力应变曲线呈微应变软化型,高含水量时的应力应变曲线呈应变硬化型;在低含水量的情况下高围压时的曲线呈应变硬化型,而低围压下剪切的试样其应力应变曲线随着轴向应变的增加呈现出微弱的软化趋势。土体的抗剪强度对含水量的变化敏感性较大。随着含水量的增大,膨胀土的摩擦角线性减小;其粘聚力随含水量的增加先是增大,在最优含水量时粘聚力达到最大值,而后随着含水量的继续增加,粘聚力逐渐减小。

Based on unsaturated triaxial testing system,with different water content,the strength characteristics of expansive soils of Nanning are studied.Under certain confining pressure,with low water content,stress-strain curve is strain-softening,whereas with high water content,is strain hardening;Under high confining pressure,with low water content stress-strain curve is strain-hardening type,whereas with low confining pressure the stress-strain curve with the increase of axial strain is a slight softening trend.The shear strength of soil has a large sensitivity with moisture content.As the moisture content increases,the expansive soil friction angle decreases linearly.With the increase of water content,firstly its cohesive force increases,it reaches maximum value at the optimum water content,then it decreases with the increase of water content.