基于现场地质调查和室内试验,再结合非饱和土力学理论建立计算模型,将孔隙水压力分布和非饱和强度理论应用到极限平衡法中,对降雨作用下秦巴山区紫阳县的凹陷地形滑坡体进行瞬态渗流、稳定性的饱和-非饱和数值计算。结果表明:凹陷地形易汇水并诱发滑坡,单位厚度坡体产生的最大孔压与该凹陷地形面积大小成正比;单位土层厚度的1 000 m2的凹陷地形范围内最大能产生1.47 kPa的孔压。研究结果可供类似地形中滑坡体渗流和稳定性的数值计算参考。
Abstract
Through field investigation and lab analysis, computation models of landslides with topographic hollows in Ziyang county of the Qinling-Daba Mountains were set up based on unsaturated soil mechanics theory. The stability and seepage with saturated and unsaturated properties under transient conditions were computed by limit equilibrium method in consideration of pore water pressure and unsaturated strength. Results show that topographic hollows induce slope failure through convergence of subsurface flow into small areas in the slope. Per unit depth of the maximum pore water pressure measured in an area close to the base of topographic hollows was found to be higher with bigger topographic hollows. Furthermore, a threshold relationship between the topographic hollow area and maximum pore water pressure in this study indicates that a topographic hollow of 1 000 m2 area could generate a maximum pore water pressure of 1.47 kPa.
关键词
浅层滑坡 /
凹陷地形 /
秦巴山区 /
孔隙水压力 /
安全系数
Key words
shallow landslides /
topographic hollows /
Qinling and Daba Mountains /
pore water pressure /
factor of safety
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基金
国家自然科学基金项目(41272282);中国地质调查局地质调查工作项目(1212011220135)
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