负温和初始含水率对冻结粉质黏土力学性质的影响  

Effects of Negative Temperature and Initial Moisture Content on Mechanical Properties of Frozen Silty Clay

作　　者：孙义强 孟上九[1,2,3] 王淼 汪云龙[1] SUN Yiqiang;MENG Shangjiu;WANG Miao;WANG Yunlong(Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;College of Civil Engineering and Architecture,Harbin University of Science and Technology,Harbin 150080,China;College of Architecture and Civil Engineering,Jiamusi University,Jiamusi 154007,China)

机构地区：[1]中国地震局工程力学研究所地震工程与工程振动重点实验室,黑龙江哈尔滨150080 [2]哈尔滨理工大学建筑工程学院,黑龙江哈尔滨150080 [3]佳木斯大学建筑工程学院,黑龙江佳木斯154007

出　　处：《应用基础与工程科学学报》2021年第1期193-205,共13页Journal of Basic Science and Engineering

基　　金：黑龙江省科学基金项目(E2017064);中国地震局工程力学研究所基本科研业务费专项项目(2018D12);国家自然科学基金项目(51378164)。

摘　　要：温度和含水率是决定冻土性质的两个主要因素.通过开展低温三轴试验,研究了冻结状态下路基粉质黏土在50kPa围压,4个温度水平(-4、-6、-8、-10℃)、4种初始含水率(14.30%、16.20%、18.73%、20.60%)共计16种工况下的变形及强度等力学性质.结果表明:冻结粉质黏土的应力-应变关系在各温度及初始含水率条件下均呈软化型,随温度降低软化程度减弱;除个别试验点外,温度及初始含水率对试样轴向破坏应变的影响均存在临界值,使破坏应变随其变化先增大后减小;试样初始切线模量受温度的影响要比初始含水率显著,当含水率相同时其值随温度降低而增加,但增速渐缓;含水率相同时,试样三轴抗压强度随温度降低近似线性增大;同一温度下抗压强度随试样初始含水率变化以16.20%为临界值,其值先增大后减小并趋于稳定.本文提出了考虑温度和含水率条件的冻结粉质黏土抗压强度计算公式,可用于预估冻结粉质黏土的三轴抗压强度.Temperature and moisture content are two main factors affecting the frozen soil’s property.To investigate the deformation and strength behaviors of frozen subgrade silty clay,lowtemperature triaxial tests were conducted under a confining pressure of 50 kPa. A total of 16 conditions,i. e.,4 temperature(-4℃,-6℃,-8℃,and-10℃) and 4 initial moisture contents( 14. 30%,16. 20%,18. 73%,and 20. 60%) were considered in the experiments.Results indicate: The stress-strain curve softened at all temperature and initial moisture contents,and the softening degree decreased with temperature. In general,there was a critical temperature and moisture content,at which the failure strain first increased and then dropped.Compared with the initial moisture content,the temperature had a greater impact on the initial tangential modulus. Under the same moisture content,the initial tangential modulus increased with the falling temperature at a gradually slower rate. When the moisture content was constant,the specimen’s triaxial compressive strength increased linearly with the decreased temperature.At the same temperature,the compressive strength first increased with the initial moisture content until a critical value of 16. 20%,then it decreased and tended to be stable. The calculation formula,which considered the temperature and initial moisture content,was proposed to estimate the frozen silty clay’s triaxial compressive strength.

关 键 词：冻结粉质黏土 三轴试验 抗压强度 变形特性 负温温度 初始含水率 

分 类 号：TU411.3[建筑科学—岩土工程]