摘要
近年来,随着“治沟造地”和“固沟保塬”等工程在黄土高原的陆续开展,出现了许多直线型黄土填方边坡。降雨是诱发边坡失稳的重要因素,但对降雨诱发直线型黄土填方边坡变形演化特征和破坏模式的研究较少。以直线型黄土填方边坡为研究对象,通过传感器监测、三维激光扫描和人工降雨,开展室内降雨模型试验,记录了降雨入渗下边坡内部水文响应特征和边坡失稳破坏过程,并对湿润锋、土颗粒运移、坡体内部变形响应、裂缝演化特征及破坏模式进行了分析。试验结果表明:随着降雨入渗,湿润锋达到后,体积含水率增加,并在峰值后保持稳定,而基质吸力则减小,到达最低点后保持稳定。冲沟对填方边坡的影响较大,它的发育改变了坡体内含水率特征,同时也是控制边坡整体滑动的边界;边坡变形响应区域主要是以填方边坡前缘堆积区和后缘滑塌区为主;裂缝演化方向由边坡前缘向后缘发展,它的发育为雨水入渗提供优势通道,同时也加剧边坡的变形破坏;降雨形成的水动力驱使坡体中细颗粒从填方边坡后缘向前缘流失,减弱了土体颗粒之间的胶结能力,使其抗剪强度降低,进而使边坡失稳破坏。因此,在降雨入渗下,直线型黄土填方边坡的变形破坏模式为:坡顶冲沟破坏、坡脚软化→局部牵引坍塌、整体失稳→块体分割、流滑破坏。研究结果可为直线型黄土填方边坡的工程建设和滑坡灾害防治提供理论参考。
In recent years,many linear loess fill slopes have appeared with the continuous development of“Governing valleys”and“Retaining plateau”projects in the Loess Plateau.Slope instability is induced by rainfall,which is an important factor.However,there are few studies on the deformation evolution characteristics and failure modes of rainfall-induced linear loess fill slopes.In this paper,the linear loess fill slope is taken as the research object,and the indoor rainfall model test is carried out through sensor monitoring,three-dimensional laser scanning technology and artificial rainfall system.The hydrological response characteristics and failure process of slope under rainfall infiltration are recorded,and the wetting front,soil particle migration,internal deformation response,fracture evolution characteristics and failure mode are analyzed.The test results show that with the infiltration of rainfall,when the wetting front is reached,the volumetric moisture content increases and remains stable at the maximum,while the matric suction decreases and remains stable at the minimum.The gully has a greater impact on the fill slope.The development of slope changes the characteristics of the water content in the slope,and at the same time it is the boundary that controls the overall sliding of the slope.The deformation response area of the slope is mainly the front accumulation area and the back slide area of the filling slope.The cracks evolve from the leading to the trailing edge,and its development offers preferential seepage channels for the infiltration of rainwater.At the same time,the cracks also intensifies the deformation and failure of the slope.The hydrodynamic force formed by rainfall drives the loss of fine particles in the slope from the rear edge of the fill slope to the front edge,weakens the cementation among the soil particles,reduces the shear strength,and causes the slope instability and failure.Therefore,under the rainfall infiltration,the deformation and failure modes of the linear loess fill slope are:gully failure at the top of slope and toe softening→local traction collapse and overall instability→block segmentation and at last the flow slip failure.The research results can provide a theoretical reference for the engineering construction of linear loess fill slope and the prevention and control of landslide disaster.
作者
陈林万
张晓超
裴向军
张硕
龚伟翔
钟玉健
CHEN Linwan;ZHANG Xiaochao;PEI Xiangjun;ZHANG Shuo;GONG Weixiang;ZHONG Yujian(State Key Laboratory of Geohazard Prevention and Geoenvironmental Protection,Chengdu University of Technology,Chengdu,Sichuan 610059,China;College of Geosciences and Engineering,North China University of Water Resources and Electric Power,Zhengzhou,Henan 450045,China)
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2021年第6期151-160,共10页
Hydrogeology & Engineering Geology
基金
国家自然科学基金项目(41790445)
国家重点研发计划项目(2018YFC1504702)。
