膨胀土边坡浅层坍滑破坏原因剖析

Discuss of Reasons for Shallow Landslide of Expansive Soil Slope

浅层坍滑是绝大多数膨胀土路堑边坡在降雨期或雨后常发生的地质灾害,往往造成新建公路的交通中断、沿线生态环境破坏并需投入巨额的修复费用,而其破坏的真正原因目前仍不十分清楚。为此,通过对试验数据的分析,研究干湿循环条件下膨胀土的抗剪强度衰减规律,得到浅、表层边坡土体强度具有非线性性质,并认为该特性是因土固有的膨胀性本质所致;进一步开展干湿循环作用下膨胀土边坡的浅层坍滑分析,发现黏聚力的严重衰减是导致浅层坍滑破坏最重要的原因。因此,进行膨胀土边坡稳定性分析时,只有采用实测土样的非线性强度参数,才能获得与实际较为吻合的分析计算结果。

The vast majority of expansive soil cutting slope often occurs shallow landslide geological disasters during or after rainfall,which causes the newly-built highway traffic disruption,ecological environment destruction along the road and a huge cost required for repair. However,the real reason for this failure is still not very clear. Therefore,through the analysis of test data,the attenuation law of shear strength of expansive soil under the condition of dry-wet cycles is studied. It is obtained that the shear strength of surface soil has the nonlinear property,and it is considered that this characteristic is caused by the inherent expansion nature of soil. Further,the shallow landslide of expansive soil slope under the action of dry-wet cycles is analyzed.It is found that the serious attenuation of cohesion is the most important reason for shallow landslide of expansive soil slope. Therefore,the measured nonlinear strength parameters of soil samples should be applied to analyze the stability of expansive soil slope,thus the result of which can be in good agreement with the calculation result of the actual condition.