人工冻融黏土导热系数试验研究

Experimental Study on Thermal Conductivity Coefficient on Underground Engineering Artificial Frozen Clay

基于TC3000型热线法导热系数测试原理,研制了人工冻土导热系数测试系统,该系统具有温度精度高、测试速度快、测试灵活等优点。对冻结地下工程岩土进行了导热系数试验研究,获得人工冻结黏土随干密度、含水率、外界环境温度变化对冻土导热系数的影响规律。试验结果表明:冻融土导热系数随干密度呈线性增加,平均增长速率为0.20~0.25 W/m·K之间;冻融土导热系数随含水率变化平均增长速率相差不超过0.03 W/m·K;温度每降低1℃,冻融土导热系数增加0.01~0.014 W/m·K。研究成果可为类似冻结工程中测试土体导热系数提出一种新的有效方法,对人工冻结温度场计算具有重要指导意义。

Coefficient of thermal conductivity test principle based on TC3000 type hot wire method to develop artificial frozen soil thermal conductivity test system,the system has high temperature precision,fast measurement speed flexible test etc.Through the freeze underground engineering carried out experimental study of thermal conductivity coefficient to obtain artificial frozen clay with varies of outer circumstance temperature,dry density and moisture content on the influence law of thermal conductivity coefficient of frozen soil,the results show that the average growth rate of thermal conductivity coefficient of frozen soil with dry density increases is 0.20 ~ 0.25 W/m·K; the average growth rate of thermal conductivity coefficient of soil under freeze-thaw condition with change of moisture content is less than 0.03 W/m,K; thermal conductivity coefficient of frozen clay increases 0.01-0.014 W/m· K when temperature decreases 1℃.Research results can provide a new effective method to test thermal conductivity coefficient of soil in the similar projects,it has important guiding significance to the artificial freezing temperature field calculation.