三峡库区降雨型滑坡入渗特征及变形机制——基于一维和二维模型试验研究  

Infiltration characteristics and deformation mechanism of rainfall-induced landslides in Three Gorges Reservoir Area based on 1D and 2D model tests

作　　者：王力[1,2,3] 南芳芸 王世梅 陈勇[1,2] 李小伟[4] 范志宏[1,2] 陈玙珊 WANG Li;NAN Fang-yun;WANG Shi-mei;CHEN Yong;LI Xiao-wei;FAN Zhi-hong;CHEN Yu-shan(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University,Yichang,Hubei 443002,China;College of Civil Engineering&Architecture,China Three Gorges University,Yichang,Hubei 443002,China;Badong National Observation and Research Station of Geohazards,China University of Geosciences,Wuhan,Hubei 430074,China;Central-South Institute of Metallurgical Geology,Yichang,Hubei 443002,China)

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室,湖北宜昌443002 [2]三峡大学土木与建筑学院,湖北宜昌443002 [3]中国地质大学(武汉)湖北巴东地质灾害国家野外科学观测研究站,湖北武汉430074 [4]中南冶金地质研究所,湖北宜昌443002

出　　处：《岩土力学》2023年第5期1363-1374,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金联合基金重点项目(No.U21A2031);湖北省重点研发计划(No.2022BAA047);三峡库区地质灾害教育部重点实验室开放基金(No.2022KDZ19);湖北巴东地质灾害国家野外科学观测研究站开放基金(No.BNORSG-202207)。

摘　　要：强降雨诱发古滑坡的浅层变形是三峡库区最为严重的地质灾害,因此,探索暴雨作用下滑坡土体的入渗规律及其浅层变形机制具有重要的研究意义。以三峡库区的降雨型滑坡为研究对象,统计了降雨型滑坡土体的渗透特性分布特征,考虑强降雨作用,分别开展一维土柱入渗试验和二维滑坡模型试验,研究了不同降雨强度条件下滑坡土体的入渗特征以及对应的滑坡浅层变形机制。降雨入渗试验结果表明:降雨入渗土体的速度取决于降雨强度与土体渗透系数的相对大小,当降雨强度小于或等于土体渗透系数时,入渗能力随降雨强度增大而增大。当降雨强度大于土体渗透系数时,入渗能力反而随之减小。模型试验结果表明:强降雨入渗时,会造成地表土体暂态饱和,表层土体以下非饱和区内的气体被暂态封闭并受到表层孔隙水压力作用而压缩,导致孔隙气压力随降雨入渗迅速增大。对于三峡库区的降雨型滑坡,短时的暴雨会产生瞬态饱和区。封闭气体,这也是影响强降雨入渗能力的主要原因;同时封闭气体传递水压使得浅层土体的孔隙水压力骤增,这也是许多滑坡发生浅层变形和破坏的主要原因。Shallow deformation of ancient landslides induced by heavy rainfall is the most serious geological disaster in China's Three Gorges Reservoir Area(TGRA).It is important to explore the infiltration characteristics and its shallow deformation mechanism caused by heavy rainfall.In this study,the rainfall-induced landslide of the TGRA was selected as the research object,and the distributions of the soil permeability coefficients for rainfall-type landslide were summarized.Considering the effects of heavy rainfall,one-dimensional(1D) soil column infiltration test and two-dimensional(2D) landslide model test were conducted to study the infiltration characteristics of landslide soil and the corresponding shallow deformation mechanisms under different rainfall intensities.The results of the rainfall infiltration tests show that the speed of rainfall infiltration into soil depends on the magnitudes of rainfall intensity and soil permeability coefficient,i.e.when the rainfall intensity is less than or equal to the soil permeability coefficient,the infiltration capacity increases with rainfall intensity;when the rainfall intensity is greater than the soil permeability coefficient,the infiltration capacity decreases.The model test results show that the infiltration of heavy rainfall makes the surface soil transiently saturated and then the gas in the unsaturated zone below the surface is temporarily closed,which leads to the compression of gas by the surface pore water pressure.This means that the pore gas pressure increases with the infiltration of heavy rainfall.Overall,for the rainfall-induced landslides in TGRA,short-term torrential rain can create transient saturation zones and generate closing gas which is the main reason affecting the infiltration capacity of heavy rainfall.The water pressure transmitted by the closing gas causes the pore water pressure of the shallow soil to increase sharply,which is also the main reason for the shallow deformation and damage of many landslides.

关 键 词：三峡库区 模型试验 降雨诱发滑坡 入渗特征 变形机制 

分 类 号：TU411[建筑科学—岩土工程]