强降雨作用下尾水边坡非饱和渗流特征及稳定性分析  

Unsaturated Seepage Characteristics and Stability Analysis of Tail-Water Slope under Heavy Rainfall

作　　者：牛天武 杨东升[1] 雷艳[1] 龚盛 宋腾 NIU Tianwu;YANG Dongsheng;LEI Yan;GONG Sheng;SONG Teng(PowerChina Northwest Engineering Corporation Limited,Xi'an 710065,China;Department of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)

机构地区：[1]中国电建集团西北勘测设计研究院有限公司,西安710065 [2]西安科技大学建筑与土木工程学院,西安710054

出　　处：《西北水电》2024年第1期73-78,共6页Northwest Hydropower

基　　金：国家自然科学基金(51979218,U1965107)。

摘　　要：为探究抽水蓄能电站尾水边坡在强降雨作用下的稳定性,基于饱和-非饱和渗流理论模拟了强降雨条件下尾水边坡渗流场的分布及变化情况,并结合渗流计算结果,利用强度折减法对降雨条件下边坡稳定性进行了分析。结果表明:当降雨强度超过土体的饱和渗透系数时,坡脚和坡表下部率先出现暂态饱和区域,随着降雨历时的增加,润湿锋不断向坡体内部移动;长期降雨期间,边坡稳定性系数的变化主要由两个因素决定,一是孔隙水压力增加导致的有效应力减小,二是表层土体饱和容重增加导致的下滑力增加;降雨过程中边坡的稳定性系数不断减小,在降雨3d后稳定性系数发生突变;降雨前期边坡潜在滑面为弧形,随着降雨历时的增加滑面深度变浅,降雨后期边坡潜在滑面表现为沿润湿峰分布的直线形滑面,且随降雨持续作用,滑面随润湿锋向坡体内部移动。In order to explore the stability of the tailwater slope of pumped storage power station under the action of heavy rainfall,the distribution and change of the seepage field of the slope under the condition of heavy rainfall are simulated based on the saturation-unsaturated seepage theory,and combined with the seepage calculation results,the strength reduction method is used to analyze the stability of the slope under the condition of rainfall.The results show that when the rainfall intensity exceeds the saturated permeability coefficient of soil,the transient saturation zone appears first at the foot of slope and the lower part of the slope surface.With the increase of rainfall duration,the wetting front moves inward to the slope.During long-term rainfall,the variation of slope stability coefficient is mainly determined by two factors:one is the decrease of effective stress caused by the increase of pore water pressure and the other is the increase of sliding force caused by the increase of saturated bulk density of surface soil.The stability coefficient of slope decreases continuously during the rainfall process,and suddenly changes after 3d rainfall.In the early stage of rainfall,the slope potential slip surface is arc-shaped,and the sliding surface depth becomes shallow with the increase of rainfall duration.In the late stage of rainfall,the potential slip surface of the slope appears to be distributed along the wetting peak A linear slip surface,and as rainfall continues to act,the slip surface moves toward the interior of the slope along with the wetting front.

关 键 词：边坡工程 降雨入渗 非饱和渗流 渗透稳定性 数值模拟 

分 类 号：TU457[建筑科学—岩土工程]