降雨条件下浅层滑坡稳定性探讨  

Discussion on stability of shallow landslide under rainfall

作　　者：常金源[1,2] 包含[2,3] 伍法权[2] 常中华[2] 罗浩[4] 

机构地区：[1]绍兴文理学院土木工程学院,浙江绍兴312000 [2]中国科学院地质与地球物理研究所,北京100029 [3]中国科学院大学,北京100049 [4]中国地震局地质研究所活动构造与火山重点实验室,北京100029

出　　处：《岩土力学》2015年第4期995-1001,共7页Rock and Soil Mechanics

基　　金：国家"十二五"科研支撑计划项目(No.2012BAK10B06-02);中国地质调查局工作项目(No.1212011140001);绍兴文理学院科研启动项目(No.20145015)

摘　　要：降雨条件下浅层滑坡是一种常见、多发的地质灾害现象,为了解边坡稳定性随降雨入渗过程的变化情况,以Green-Ampt入渗模型为基础,并考虑了动水压力的作用,建立了降雨入渗条件下浅层滑坡的概念模型,分别推导了降雨前有、无地下水位条件下的边坡安全系数与降雨时间的关系表达式。从分析结果中可以看出,对于这两种情况下边坡稳定性发生突变的主要原因归结于:前者为在湿润锋与地下水位面接触的短时间内,滑带处的孔隙水压力迅速增高;后者为滑带在浸水饱和情况下,岩土体的强度迅速降低。在此基础上,根据降雨过程中边坡是否达到饱和,提出边坡饱和临界时间的概念,考虑了初始降雨强度小于土壤入渗能力的情况。这个时间可以作为一个参数指标用于浅层滑坡的预警。Rainfall-induced shallow landslide is a type of commonly occurring geohazards. To explore the evolution of the slope stability during a rainfall event, a conceptual model of rainfall-induced shallow landslide with considering the effect of transient pore water pressure is developed based on the Green-Ampt infiltration model, and the relationship between the factor of safety and precipitation duration for the slope with or without ground water is developed. The results show that for the slope with underground water, the pore water pressure in the slip zone drastically increases once after the wetting front touches the groundwater table; for the slope without ground water, the slip zone become inundated in the water and the soil strength decrease quickly. Based on these results,and according to whether the shallow landslide is completely saturated or not during rainfall, a concept of critical saturating time is proposed, with considering the case that the initial rainfall intensity is less than the soil’s infiltration ability. This critical time can be used as a parameter for early warning the shallow landslide.

关 键 词：浅层滑坡 GREEN-AMPT入渗模型 降雨入渗 饱和临界时间 

分 类 号：TU42[建筑科学—岩土工程]