基于改进极限平衡法的非饱和边坡稳定分析  

Study on Stability of Unsaturated Soil Slope under Rainfall Based on Improved Limit Equilibrium Method

作　　者：刘勇[1] LIU Yong(China Railway Siyuan Survey and Design Group Co.Ltd,Wuhan,Hubei 430063,China)

机构地区：[1]中铁第四勘察设计院集团有限公司,武汉430063

出　　处：《铁道工程学报》2018年第8期38-43,66,共7页Journal of Railway Engineering Society

摘　　要：研究目的:极限平衡法是非饱和土边坡稳定分析最为常见的方法之一,但由于降雨入渗时边坡的渗流场是瞬态的,这导致很多工程在使用极限平衡法进行边坡稳定分析时常常使用了错误的有效应力及剪切强度。本文以合福铁路古田北站的非饱和土边坡为研究对象,在改进极限平衡法、室内试验及数值模拟的基础上进行降雨入渗对非饱和土边坡稳定性的影响规律研究。研究结论:(1)降雨量、降雨频率、降雨时间与非饱和土边坡的瞬态渗流场、有效应力场及边坡稳定安全系数密切相关;(2)通过计算确定古田北站非饱和土边坡失稳发生在5月份,这与边坡实际失稳的时间吻合;计算确定的边坡滑移位置与边坡实际滑移位置也相同;(3)数值分析结果表明,采用改进的极限平衡法来预测非饱和土边坡的稳定性是有效的,可以作为施工方案的依据。Research purposes： Limit equilibrium method is one of the most common methods of unsaturated soil slope stability analysis. The transient seepage field was generated due to rainfall infiltration. The wrong effective stress and shear strength was used in many engineers. In this paper, taking unsaturated soil slope of Gutian North station of Hefei - Fuzhou railway as the research object, based on improved limit equilibrium method, laboratory test and numerical simulation, the law of stability of unsaturated soil slope under rainfall was studied. Research conclusions：（ 1 ） The rainfall capacity, rainfall frequency and rainfall time were closely related to transient seepage field, effective stress field and safety factor of slope stability. （2） The calculations determined failure time was May. The result was accordance to project site. The failure location was unanimous to project site. （3） The improved limit equilibrium method is effective to predict the slope stability. The results can be used as the basis of engineering change.

关 键 词：改进极限平衡法 基质吸力 稳定性 非饱和土边坡 

分 类 号：U213.13[交通运输工程—道路与铁道工程]