淤泥质黏土火灾高温下导热系数的试验研究  

Experimental studies on coefficient of thermal conductivity of silty clay

作　　者：徐婕[1,2] 朱合华[1,2] 闫治国[1,2] 

机构地区：[1]同济大学岩土及地下工程教育部重点实验室,上海200092 [2]同济大学地下建筑与工程系,上海200092

出　　处：《岩土工程学报》2012年第11期2108-2113,共6页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(50978197);教育部创新团队发展计划项目(IRT1029);上海市领军人才计划与曙光跟踪计划项目

摘　　要：对火灾高温下隧道衬砌结构周围饱和软黏土的热传导特性进行了试验研究,旨在进一步探讨作用于隧道结构上的荷载变化,以便准确评价其安全状态。采用热探针程序法(美国材料与试验协会(ASTM)确定土体和软岩导热系数的标准方法),应用自行研制的高温土体导热系数测定仪测定了上海淤泥质黏土在高温下的导热系数。试验分别测定了不同温度及不同含水率条件下土样的导热系数,并以KD2导热系数测定仪作为校准仪器对试验结果进行了校正。试验结果表明:导热系数随着温度的升高而增大,且其增大的速率随温度的增加而减小,特别是对含有机质的淤泥质黏土因有机质的高温分解而使得这种降低更加明显;此外,在不同高温下土体导热系数随含水率的增加而增大。The researches on heat conduction characteristics of soft soil under high temperature are performed for further determining the load change on tunnel lining structure surrounded by saturated soft soil and accurately evaluating its safety under high temperature of fire.The experiment adopts the method of thermal needle probe procedure,proposed by American Society for Testing and Materials（ASTM） as the standard method for determination of thermal conductivity of soil and soft rock,by using self-made apparatus for coefficient of thermal conductivity of soil to measure the coefficient of thermal conductivity of Shanghai mucky clay under high temperature.The thermal conductivity of soil samples with different water contents is measured respectively under different temperatures.At the same time,as calibrating instrument,the KD2 thermal conductivity measuring apparatus is used to calibrate the test results.The test results indicate that the thermal conductivity of soil with the same water content increases with the increase of temperatures.When the temperature is low,the increase rate of thermal conductivity of soil is higher,and when the temperature is high,the increase rate of thermal conductivity of soil is lower,which is more serious due to the decomposition of the organic soil under high temperatures.Further,the thermal conductivity of soil with the same temperature increases with the increase of water content.

关 键 词：淤泥质黏土 高温 导热系数 热探针程序法 

分 类 号：TU411[建筑科学—岩土工程]