摘要
为了探索快速评价重金属污染红黏土强度特性的新型手段,在室内开展不同浓度、不同干密度的Cu^(2+)污染红黏土的直剪试验及其电阻同步测试试验,得到土体剪应力、电阻率-剪切位移同步变化曲线;分析初始干密度、垂直压力、Cu^(2+)浓度对抗剪强度、电阻率的影响;依照抗剪强度指标(C、φ)原理选取电阻率指标(ρ_(0)、φ_(0)),并分析Cu^(2+)浓度对抗剪强度指标(C、φ)、电阻率指标(ρ_(0)、φ_(0))的影响;以Cu^(2+)浓度为中间变量,进一步探讨抗剪强度与破坏电阻率、抗剪强度指标(C、φ)与电阻率指标(ρ_(0)、φ_(0))之间的定量关系。试验结果表明:Cu^(2+)污染红黏土剪应力-位移曲线呈典型的应变硬化型,电阻率随剪切位移的增大而减小;抗剪强度随初始干密度、垂直压力的增大近似线性增大,而电阻率随初始干密度、垂直压力的增大近似线性减小;抗剪强度及其指标(C、φ)、电阻率及其指标(ρ_(0)、φ_(0))与Cu^(2+)浓度间均呈负指数函数关系;抗剪强度与破坏电阻率、黏聚力与初始电阻率、内摩擦角与电阻率关系曲线倾角间的变化趋势一致,均呈现出较好的指数函数关系,可用于快速评价Cu^(2+)污染红黏土强度特性变化。
The aim of this research is to explore a new method for evaluating the strength characteristic rapidly of heavy metal-contaminated red clay.Direct shear test and resistivity test were carried out for Cu^(2+)contaminated red clay specimens of varied concentration and dry density.The curves of shear stress and resistivity of Cu^(2+)contaminated red clay varying synchronously with shear displacement were obtained.Meanwhile,the impacts of initial dry density,vertical pressure,and Cu^(2+)concentration on shear strength and resistivity were analyzed.According to the principle of shear strength indexes(C and φ),resistivity indexes(ρ_(0) and φ_(0))were selected,and the effects of Cu^(2+)concentration on shear strength indexes and resistivity indexes were examined.Furthermore,the quantitative relations between shear strength(indexes)and destructive resistivity(indexes)were discussed.Test results unveiled that the shear stress-displacement curve of Cu^(2+)contaminated red clay displayed typical strain hardening features,while resistivity declined with the increase of shear displacement.Shear strength augmented approximately linearly with the growing of initial dry density and vertical pressure while destructive resistivity showed opposite trend.Both shear strength(indexes C andφ)and resistivity(indexes ρ_(0) and φ_(0))were in a negative exponential functional relation with Cu^(2+)concentration.In addition,the curve of shear strength vs.resistivity,curve of cohesion vs.initial resistivity,and curve of internal friction angle vs.inclination of resistivity relation curve displayed consistent trend,showing a good positive exponential function relationship.
作者
陈议城
黄翔
陈学军
张晓宸
班如龙
CHEN Yi-cheng;HUANG Xiang;CHEN Xue-jun;ZHANG Xiao-chen;BAN Ru-long(Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin 541004,China)
出处
《长江科学院院报》
CSCD
北大核心
2021年第3期121-127,136,共8页
Journal of Changjiang River Scientific Research Institute
基金
国家自然科学基金项目(41762022)
桂林市科技开发项目(20170222)
广西中青年教师基础能力提升项目(2018KY0239)
广西科技计划项目(2017GXNSFBA198052)。
