铜尾矿砂—红黏土混合料三轴剪切特性  

Triaxial Shear Characteristics of Copper Tailings Sand-Red Clay Mixtures

作　　者：王升福 罗成文 闫乐琛 薛凯喜[1] 嵇晓雷[2] 李向辉 WANG Sheng-fu;LUO Cheng-wen;YAN Le-chen;XUE Kai-xi;JI Xiao-lie;LI Xiang-hui(College of Civil and Architectural Engineering,East China University of Technology,Nanchang 330013,China;Jiangsu Open University,Nanjing 210036,China;China Railway 16th Bureau Group Road and Bridge Engineering Co.Ltd.,Beijing 101500,China)

机构地区：[1]东华理工大学土木与建筑工程学院,南昌市330013 [2]江苏开放大学,南京市210036 [3]中铁十六局集团路桥工程有限公司,北京市101500

出　　处：《公路》2024年第11期312-321,共10页Highway

基　　金：国家自然科学基金资助项目,项目编号42167024,52168043,42061011;江西省自然科学基金资助项目,项目编号20224BAB204068;核技术应用教育部工程研究中心开放基金资助项目,项目编号HJSJYB2022-5;江西省地质环境与地下空间工程研究中心开放基金项目,项目编号JXDHJJ2022-002。

摘　　要：利用江西地区分布广泛的红黏土与铜尾矿砂混合,采用三轴试验研究不同粒径组(0.25~0.5 mm、0.1~0.25 mm、0.075~0.1 mm、<0.075 mm)和不同红黏土掺量(10%、20%、40%、60%)条件下铜尾矿砂—红黏土混合料抗剪强度和变形特性。结果表明:铜尾矿砂粒径越大,土体抗剪强度越大,且在红黏土掺量为40%时抗剪强度最高;尾矿粒径为0.2~0.5 mm条件下其应力~应变关系具有明显的应变硬化现象,粒径小于0.25~0.5 mm条件下其应力~应变关系具有明显的应变软化现象;铜尾矿砂—红黏土混合料的割线弹性模量在围压300 kPa时,随着轴向应变的增大呈先快速减小后缓慢减小,最后趋于平缓;修正的邓肯—张模型可以很好地描述铜尾矿砂—红黏土混合料非线性变形的显著特性;依据试验数据得出不同条件下修正的邓肯—张模型参数m、n、l值,模型拟合吻合度高,说明修正的邓肯—张模型参数的可靠性较高。In the paper,the widely distributed red clay in Jiangxi Province is used to mix with copper tailings sand,triaxial shear tests are carried out to study the shear strength and deformation characteristics of copper tailings sand-red clay mixture under different particle size groups(0.25~0.5 mm,0.1~0.25 mm,0.075~0.1mm,<0.075mm)and different red clay content(10%,20%,40%,60%)conditions.The results show that,the larger the particle size of copper tailings sand,the greater the shear strength of the improved soil,and the shear strength is highest when the content of red clay is 40%.The stress-strain relationship of improved soil under the condition of copper tailings particle size ranging from 0.2 to 0.5mm exhibits obvious strain hardening phenomenon,while the stress-strain relationship of improved soil under the condition of particle size less than 0.25 to 0.5mm exhibits obvious strain softening phenomenon.The secant elastic modulus of copper tailings sand-red clay mixture decreases rapidly and then slowly with the increase of axial strain at a confining pressure of 300kPa,and finally tends to flatten out.The modified Duncan-Chang model selected can well describe the significant nonlinear deformation characteristics of copper tailings sand-red clay mixture.Based on experimental data,the values of parameters m,n,and l of the modified Duncan-Chang model under different conditions are obtained.The high fitting degree of the model indicates that the reliability of the modified Duncan-Chang model parameters is high.

关 键 词：岩土工程 铜尾矿砂 红黏土 三轴剪切试验 修正的邓肯—张模型 

分 类 号：U414.11[交通运输工程—道路与铁道工程] TU411[建筑科学—岩土工程]