渗流作用下黄土坡临江一号滑坡滑带土结构演变规律分析  

Analysis of the structure evolution law of the sliding zone soil of Huangtupo Linjiang No.1 landslide under seepage condition

作　　者：王倩芸 唐辉明[1,2] 鲁莎[2] 安鹏举 夏丁[2] WANG Qianyun;TANG Huiming;LU Sha;AN Pengju;XIA Ding(Badong National Observation and Research Station of Geohazards,China University of Geosciences(Wuhan),Wuhan 430074,China;Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan 430074,China;Institute of Rock Mechanics,Ningbo University,Ningbo 315211,China)

机构地区：[1]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 [2]中国地质大学(武汉)工程学院,湖北武汉430074 [3]宁波大学岩石力学研究所,浙江宁波315211

出　　处：《安全与环境工程》2024年第6期134-144,共11页Safety and Environmental Engineering

基　　金：国家自然科学基金重大项目(42090050)。

摘　　要：三峡库区的堆积层滑坡常年经历着库水和季节性降雨的作用,坡体内部的渗流场随之产生周期性的变化。渗流作用是影响滑带土微观结构演变,从而影响滑带强度及整体稳定性的重要因素。为揭示滑带在渗流作用下的结构演变规律,以黄土坡临江一号滑坡为例,对历经不同渗流时长的重塑滑带土样开展了电镜扫描试验(SEM),同时测得各渗流时长下滑带土的渗透系数,并结合原状滑带土样微观结构的扫描结果,分析探讨了渗流作用对滑带土结构演变的影响。结果表明:渗流作用会改变土体孔隙结构特征;随着渗流时长的增加,细小的黏土颗粒被搬运、填充至较大的孔隙中,使得有效渗流通道减少至逐步趋于稳定,渗透系数因此随之减少至趋于稳定;临江一号滑坡滑带土的初始渗透系数为2.88×10^(-7)cm/s,48 h后渗透系数降低至2.32×10^(-7)cm/s,渗流72 h后渗透系数稳定于2.30×10^(-7)cm/s;滑坡体内各地质单元的结构不同,渗流对滑坡体的作用也不尽相同,地下水的渗流作用在不同地质体层间存在较大的差异,可能存在界面渗流现象。该研究可为滑坡变形及稳定性评价提供参考。The accumulation landslides in the Three Gorges reservoir area experience the effects of reservoir water and seasonal rainfall throughout the year,leading to periodic variations in the internal seepage field.Seepage action is an important factor that influences the microstructural evolution of the sliding zone soil,consequently,its strength and overall stability.In order to reveal the structural evolution patterns of the sliding zone under seepage conditions,this study took the Huangtupo Linjiang No.1 landslide as an example.Remoulded sliding zone soil samples with different durations of seepage were subjected to scanning electron microscopy(SEM)analysis.The permeability coefficients of the sliding zone soil were also measured at each seepage duration.By combining the scanning results of the microstructure of the in-situ sliding zone soil,the influence of seepage action on the structural evolution of the sliding zone was analyzed and discussed.The results show that seepage changes the structural characteristics of the pore space.With the increase in seepage time,the fine clay particles are transported and filled into the larger pore space,so that the effective seepage channel is reduced to stabilize gradually and the permeability coefficient is reduced to stabilize.The initial permeability coefficient of the sliding zone soil of the Linjiang No.1 landslide is 2.88×10^(-7) cm/s,and it is reduced to 2.32×10^(-7) cm/s after 48h and stabilized at 2.30×10^(-7) cm/s after 72 h of seepage.Furthermore,combined with the material composition and structural characteristics of the actual geological body of the Linjiang No.1 landslide,it is considered that the seepage effect on the landslide body varies with the structure of each geological unit within the landslide.The seepage effect of groundwater varies considerably between the layers of different geological bodies,and there may be interfacial seepage.This study can provide a reference for landslide deformation and stability evaluation.

关 键 词：库岸滑坡 渗流作用 滑带土 渗透系数 微观结构 

分 类 号：X43[环境科学与工程—灾害防治] P642.22[天文地球—工程地质学]