降雨入渗下非饱和土边坡浅层破坏机制分析  

Shallow failure mechanism of unsaturated soil slope during rainfall infiltration

作　　者：王骜洵 蒋函静 许帅 徐永福[1] WANG Aoxun;JIANG Hanjing;XU Shuai;XU Yongfu(Department of Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学土木工程系,上海200240

出　　处：《中南大学学报（自然科学版）》2024年第7期2701-2711,共11页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(42330701);国家重点研发计划项目(2019YFC1509800)。

摘　　要：通过孔隙表面分维描述土的孔隙结构,应用分形模型确定非饱和土的水力特性。选取基质吸力变化分布作为评价指标,通过二维渗流计算获取降雨-蒸发循环作用下非饱和土边坡的扰动程度和大气影响深度。进一步分析土的孔隙表面分维、进气值和饱和渗透系数及降雨强度与非饱和土边坡的浅层破坏形式的相关性。研究结果表明:降雨-蒸发循环作用引起的边坡土层的基质吸力变化比体积含水率的变化显著;土的孔隙表面分维、进气值和饱和渗透系数均与大气影响深度呈正相关,降雨强度影响较小;基质吸力可以作为边坡扰动程度和大气影响深度的评价指标;非饱和土边坡浅层破坏形式受土的孔隙表面分维、进气值和饱和渗透系数控制,与降雨强度相关性低。本研究可为非饱和土边坡浅层破坏及相关工程地质问题研究提供参考。The pore surface fractal dimension was used to characterize pore structure of soil,and the fractal model was applied to predict the hydraulic parameters of unsaturated soil.The degree of disturbance and the depth of atmospheric effect on unsaturated soil slopes in the rainfall-evaporation cycle were determined using two-dimensional infiltration calculations,and the distribution of matric suction change was chosen as an assessment index.The relationship between the pore surface fractal dimension,air-entry value,saturated permeability coefficient of the soil,rainfall intensity and the shallow failure form of unsaturated soil slopes was further analyzed.The results show that the change of matric suction due to rainfall infiltration is significantly greater than that of the volumetric water content.The pore surface fractal dimension,air-entry value,and saturated permeability coefficient of unsaturated soils are all positively correlated with the depth of atmospheric influence,with the intensity of rainfall having a lesser effect.Matric suction can be used as an evaluation index for the degree of slope disturbance and the depth of atmospheric influence.The pore surface fractal dimension,the air-entry value,and the saturated permeability coefficient of soil governor the form of shallow failure of unsaturated soil slopes,with a low correlation with rainfall intensity.This work provides reference for the investigation of shallow failure to unsaturated soil slopes and associated geological engineering issues.

关 键 词：孔隙表面分维 非饱和土 浅层破坏 降雨入渗 

分 类 号：TU43[建筑科学—岩土工程]