含盐量对冻结粉土单轴抗压强度影响的试验研究  

THE EXPERIMENTAL STUDY ON THE UNIAXIAL COMPRESSIVE STRENGTH OF FROZEN SILT WITH DIFFERENT SALT CONTENT

作　　者：陈锦[1,2] 李东庆[1] 邴慧[1] 邓友生[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃兰州730000 [2]中国科学院地理科学与资源研究所资源与环境信息系统国家重点实验室,北京100101

出　　处：《工程力学》2013年第12期18-23,共6页Engineering Mechanics

基　　金：国家重点基础研究发展计划(973计划)项目(2012CB026102);国家自然科学基金项目(41271080);国家自然科学基金创新群体项目(41121061);中国科学院西部行动计划项目(KZCX2-XB3-19)

摘　　要：采用取自甘肃省白银市平川区的典型天然盐渍粉土，洗去土中的盐分，在含水量为20％的情况下，以NaCl和Na2SO4为研究对象，研究了含盐量对冻结粉土单轴抗压强度和破坏应变的影响。试验结果表明：当含盐量介于0～3％时，随着NaCI含量的增加，冻土中的未冻水含量增加，土颗粒间的距离增大，凝聚力和内摩擦角减小，冻结粉土的单轴抗压强度以指数规律减小，破坏应变则呈现出先增加后减小的变化趋势。由于Na2SO4易于结晶析出，当含盐量小于3％时，盐分含量不同，盐分在土体中发挥着不同的作用，致使含盐粉土的单轴抗压强度随着含盐量的增加呈先减小后增大的变化趋势；破坏应变则呈现出先增大后减小的趋势。The saline silt, which was collected from the Pingchuan district of Baiyin city, was firstly washed off salt, and then pure NaC1 and Na2SO4 were added into the silt as the testing sample soil. Finally, the influences of salt on the uniaxial compressive strength and the failure strain were studied through uniaxial compressive tests at a constant temperature and a strain rate. The test results show that if the mass content is between 0 and 3%, as the NaC1 content increases, the unfrozen water in frozen soil and the distance between soil particles increase, cohesive force and internal friction angle of soil particles decrease, so the uniaxial compressive strength decreases in an exponential form and the failure strain increases at first and then decreases. Due to the special chemical, different Na2SO4 contents play different roles in the change of uniaxial compressive strength of frozen soil. When the mass content is between 0 and 3%, with the increase of Na2SO4, the uniaxial compressive strength of frozen silt increases at first and then decreases afterwards. While the failure strain has completely opposite changing trend with the uniaxial compressive strength.

关 键 词：NACL NA2SO4 冻结粉土 单轴抗压强度 破坏应变 

分 类 号：TU432[建筑科学—岩土工程]