饱水过程中松散土体渗透性变化研究  

A testing study of variation in permeability of unconsolidated soil under saturation

作　　者：单慧媚[1] 梁合诚[1,2] 刘佳伟[1] 蔡鹤生[1,2] 周爱国[1,2] 

机构地区：[1]中国地质大学(武汉)环境学院,武汉430074 [2]生物地质与环境地质教育部重点实验室,武汉430074

出　　处：《水文地质工程地质》2010年第5期97-101,共5页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金资助项目(40702059);湖北省自然科学基金资助项目(2007ABA148)

摘　　要：针对三峡库区广泛存在的紫红色岩(土)的工程地质特征,考虑库区水位的变化,以黄腊石滑坡群的石榴树包滑坡表层原状松散土体为研究对象,设计一定流速条件下的饱水试验,探索在流动的水溶液饱和条件下紫红色松散土体渗透性随时间的变化规律,并分析变化原因。研究发现:饱水过程中,紫红色松散土体的渗透性有很强的时间效应,随着饱水时间的积累,渗透系数呈现显著的线性增大后减小并最终趋于稳定的规律。对比饱水前后土样微观结构以及化学成分分析结果,发现水流对松散土体颗粒的物理运移以及水对土体的化学溶蚀作用、水土之间的离子交换吸附作用影响土体的结构,从而影响了紫红色土体的渗透性。Based on the engineering geological characteristics of purple rock or soil in the reservoir area of the Three Gorges,the changes in river level are considered and undisturbed soil samples are collected from surface layers of the Shiliushubao landslide in the Huanglashi landslide groups.Taken the undisturbed soil samples as a subject of investigation,a running water-saturated experiment is designed.Under the condition of soil sample saturated in running water,the permeability of purple-unconsolidated-soil is examined,the rules of permeability variation and causes are analyzed.The results show that during saturation process,purple-unconsolidated-soil permeability has an obvious time effect.As the saturation time becomes longer,the coefficient of permeability increases obviously linearly,and declines and tends to be stable at last.Compared the microstructure and chemical compositions of unsaturated soil sample with the saturated one,the testing results show that the migration of running water on soil particles,dissolution of water on soil composition and ion-exchange adsorption of water with soil can affect the soil structure,and change the permeability of the purple soil.

关 键 词：松散土体 水流 渗透系数 微观结构 化学组成 

分 类 号：P641.21[天文地球—地质矿产勘探]