含水量对黄土边坡稳定性的影响

为了研究含水量变化对黄土边坡稳定性的影响,首先对兰州某黄土边坡的黄土试样进行了不同含水量下的直剪试验。试验结果表明,随着含水量的增加,黄土的抗剪强度以幂函数形式减小。但含水量对内摩擦角的影响更显著。因为黄土的粘聚力较小,其变化对抗剪强度的影响相对较小。其次,应用直剪试验结果对四个简单边坡模型进行了黄土边坡稳定性系数随含水量变化的分析。分析表明:随着含水量的增加,黄土边坡的稳定性系数以幂函数形式逐渐降低,当含水量较高时逐渐趋缓。实际上,边坡稳定性系数随含水量变化规律与抗剪强度随含水量变化规律相似。相同坡度时,边坡的高度对稳定性系数有不太大的影响,特别当黄土边坡含水量达到9%以上时,坡高对边坡稳定性系数的影响可以忽略。

Influence of water content on loess slope stability

In order to study the influence of water content on the stability of loess slope,first,direct shear tests on loess samples with different water content secured from a loess slope in Lanzhou with different water content were carried out. The testing results show that the shear strength of the loess decreases as a power function of water content. However,water content affects the internal friction angle of loess more significantly. Because the cohesion of loess is weak,so its change with increase of water content is relatively insignificant as far as the shear strength is concerned. Secondly,the influence of water content on factor of slope stability was studied by applying the direct shear tests results to four simple slope models. It is found that the factor of slope stability decreases as a power function of water content,but at the high water content level,the change of factor of slope stability slows gradually with further increase of water content. Actually,as water content increases,the shear strength and the factor of slope stability change in a similar way. Under the same slope angle,the height of slope has a minor effect on slope stability,however,when the water content of loess slope reaches 9% and above,the effect of slope height on factor of slope stability is negligible.