基于改进Green-Ampt模型的花岗岩残积土边坡降雨入渗规律研究  

A study on the rainfall infiltration of granite residual soil slope with an improved Green-Ampt model

作　　者：潘永亮 简文星[1] 李林均 林雨秋 田朋飞 PAN Yong-liang;JIAN Wen-xing;LI Lin-jun;LIN Yu-qiu;TIAN Peng-fei(Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan,Hubei 430074,China)

机构地区：[1]中国地质大学(武汉)工程学院,湖北武汉430074

出　　处：《岩土力学》2020年第8期2685-2692,共8页Rock and Soil Mechanics

基　　金：江西省交通运输厅科技计划项目(No.2015C0026);中国地质大学(武汉)教学实验室开放基金项目(No.SKJ2018099)。

摘　　要：花岗岩残积土广泛分布于我国南方地区,具有许多不良物理力学性质。该类型土边坡在降雨作用下极易发生变形破坏,因此,对花岗岩残积土边坡的降雨入渗规律进行深入研究具有重要意义。在Green-Ampt模型的基础上综合考虑了坡体的初始含水率、地下水位、非饱和特性,建立了一种适用于不同降雨工况的入渗模型,并采用数值模拟及前人经典模型计算结果对该模型进行了验证。运用该模型对赣南3种典型降雨工况下的花岗岩残积土边坡进行了分析,结果表明:在距离地下水位线较远时初始含水率对湿润锋的迁移速率影响不大,但在接近地下水位线附近时湿润锋的迁移速率逐渐增大,呈现出指数形式的变化趋势;相同降雨时间内、不考虑坡面冲刷的情况下,降雨强度略大于土体饱和渗透系数的工况下湿润锋迁移深度最大、边坡稳定性系数降低最多,在实际情况中尤其需要加强防范。Granite residual soil is widely distributed in southern China,and it has many poor physical and mechanical properties.Slopes of this type of soil are prone to deformation and failure under the action of rainfall.Therefore,it is of great significance to study the rainfall infiltration mechanism in granite residual soil slopes.On the basis of Green-Ampt model,the initial moisture content,underground water level and unsaturated characteristics of the soil are comprehensively considered.An infiltration model suitable for different rainfall conditions is established,and verified by comparison between numerical simulations and other models.Then,the proposed model is used to analyze granite residual soil slopes under three typical rainfall conditions.The results show that the initial water content has little effect on the migration rate of the wetting front when it is far from groundwater level,whereas the migration rate increases gradually when the wetting front is near groundwater level,presenting an exponential trend.In the same rainfall time,under the condition that the rainfall intensity is slightly greater than the saturated permeability coefficient of soil,the wetting front migration depth is the largest and the slope stability factor decreases the most.

关 键 词：GREEN-AMPT入渗模型 湿润锋 初始含水率 降雨工况 边坡稳定性 

分 类 号：TU411.4[建筑科学—岩土工程]