中文摘要：

应用南宁膨胀土开展低应力下的常规饱和慢剪、固结快剪、快剪试验，获得了抗剪强度随竖向应力的变化规律，分析了低应力对抗剪强度的影响。进行了75、100、200、300 kPa竖向压力下的残余强度试验，运用Seep/W和Slope/W软件，考虑降雨入渗条件，采用 M-P、Ordinary和Bishop三种极限平衡法对各抗剪强度下膨胀土边坡的稳定性进行对比分析。分析结果表明：各抗剪强度受低应力的影响显著，均呈非线性，可用幂函数表达；饱和慢剪强度在低应力时最小，高应力时最大；采用含低应力饱和非线性慢剪强度进行边坡稳定分析结果与实际发生的浅层破坏吻合。

英文摘要：

Conventional saturated slow shear test,solidification quick shear test and quick shear test were carried out for Nanning expansive soil under low stresses condition,the change laws of various shear strengths with the change of vertical stresses were gotten,and the influences of low stresses on various shear strengths were analyzed.Residual shear strength tests were performed under the vertical stresses of 75,100,200 and 300 kPa,and the expansive soil slop stabilities at various shear strengths were compared by using the softwares of Seep/W and Slope/W with the consideration of rainfall infiltration and three limit equilibrium methods including M-P method, Ordinary method and Bishop method. Analysis result shows that the shear strengths are significantly influenced by the low stresses.The influences have nonlinear trends and the trends can be expressed by power functions.The saturated slow shear strength is lowest at low stress and highest at high stress.The stability analysis result of expansive soil slope calculated by nonlinear saturated slow shear at low stress is consistent with the actual slope failure situation. 5 tabs,11 figs,20 refs.