Specimens are the disturbed Q2 loess from the south Jingyang Plateau. According to the principal stress consolidation ratio 0. 33 which equals σ3/σ1 for consolidation, to simulate the initial stress condition of soil sample. After the completion of the consolidation, conduct the test of in the condition of lateral unloading undrained shear, in order to study the influences of the mechanical properties of Q2 loess’ cohesion and angle of internal fric-tion with water content. The test results show that when the water content increases from 10% to 30%, the cohe-sion decreases from 33. 51 kPa to 8. 18 kPa, that is, the cohesion is decreased obviously with the increase of mois-ture content, and the cohesion decreases linearly as the water content increases and the fitting correlation coefficient is 0. 970 8;when the water content ranges from 10% to 30%, the internal friction angle changes from 26. 4 ° to 29. 6 ° , and the change range of internal friction angle is 3. 2 ° , and the average angle of internal friction is 27. 99 ° , so with soil unloading the changes of water contents mainly affect the cohesion of undisturbed Q2 loess, but to the internal friction angle little.%选取陕西省泾河南塬Q2原状黄土,按主应力固结比σ3/σ1=0．33进行固结,以模拟土样原位地层的初始应力状况；固结完成后,在侧向卸荷条件下进行不排水剪试验,研究黄土滑坡过程中含水率对黄土的黏聚力、摩擦角等力学特性的影响。试验结果表明：含水率从10%→30%,黏聚力的变化范围从33．51→8．18 kPa,随着含水率的增大,黏聚力明显降低,用线性关系式可以较好地拟合黏聚力和含水率之间的关系,且拟合相关系数R为0．9708；含水率变化范围为10%~30%时,内摩擦角的变化范围为26．40°~29．60°,随着含水率的增大,内摩擦角的变化范围在3．2°以内,波动范围较小,其平均值为27．99°,因此卸荷条件下含水率变化主要影响原状黄土的黏聚力,对内摩擦角影响较小。
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