温度对黄土热参数影响的试验研究  

Experimental study of influence of temperature on thermal properties of loess

作　　者：董西好 叶万军[1] 杨更社[1] 吴迪[1,2] 申艳军 刘慧[1] DONG Xi-haol YE Wan-junl YANG Geng-she WU Di SHEN Yan-jun LIU Hui(School of Architecture and Civil Engineering, Xi＇an University of Science and Technology, Xi＇an, Shaanxi 710054, China Key Laboratory of Western Mineral Resources and Geological Engineering of Ministry ＆Education, Chang＇an University, Xi＇an, Shaanxi 710054, China)

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054 [2]长安大学西部矿产资源与地质工程教育部重点实验室,陕西西安710054

出　　处：《岩土力学》2017年第10期2888-2894,2900,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.41172262);教育部新世纪优秀人才支持计划项目(No.NCET-12-1044);陕西省重点科技创新团队计划资助项目(No.2014KCT-30);博士后基金(No.2016M592816)~~

摘　　要：黄土的热参数是黄土冻融灾害成因机制研究及热工计算中的重要指标,而温度对黄土的热参数具有一定的影响。对不同含水率、不同干密度的原状黄土试样,采用Test Protocol Hot Disk TPS 2500S型热常数分析仪,在不同温度下开展热参数试验,探讨黄土的热参数随温度的变化规律。研究结果表明:随着温度的降低,试样的导热系数变化曲线大致可分为缓慢增大、迅速增大和基本稳定3个阶段;比热容随温度的降低先增大后减小,最后趋于稳定;热扩散系数则随温度的降低先减小后增大,当温度低于-20℃时保持基本稳定;含水率越大,温度对试样热参数的影响越显著。土体处于未冻结和冻结两种状态下的热参数相差较大。干密度主要通过土体内部矿物质和自由水的含量对热参数产生影响。在黄土冻融灾害成因机制研究和热工计算中,可根据土体温度、含水率和干密度的变化动态选择热参数,而判断土体是否处于冻结状态是确定热参数的关键。The thermal properties of loess are important in the study of genetic mechanism of freezing-thawing hazard and thermal engineering calculation. However, temperature greatly impacts the thermal behaviors of loess. In this study, the thermal properties of loess samples with different water contents and dry densities are tested using Test Protocol Hot Disk TPS 2500 S under different temperatures. The evolution of thermal properties of loess with temperature is discussed. The study reveals the following results. The thermal conductivity development of samples as temperature decreases can be divided into three stages： slowly increasing stage, rapidly increasing stage and stable stage. As temperature decreasing, the specific heat capacity of samples increases initially and then decreases, finally stabilizes. The thermal diffusivity of samples decreases at first and then increases with decreasing temperature.When the temperature is below-20℃, the thermal diffusivity keeps stable. The larger the water content, the greater the influence of temperature on the thermal properties of samples. There exists large difference of thermal properties between unfrozen soil and frozen soil. Dry density impacts n the thermal properties mainly through the minerals and free water content of soil. In applications of freezing-thawing hazard and thermal engineering, thermal properties can be selected in accordance with soil temperature, water content and dry density. Determination of whether the soil is frozen or not is the key to determine the thermal properties.

关 键 词：黄土 热参数 温度 导热系数 比热容 热扩散系数 

分 类 号：TU444[建筑科学—岩土工程]