热传导CPT探头的研发与应用  

Development and application of heat conduction CPT probe

作　　者：刘松玉[1] 郭易木 张国柱[1] 周遊 LIU Song-yu;GUO Yi-mu;ZHANG Guo-zhu;ZHOU You(Institute of Geotechnical Engineering,Southeast University,Nanjing 210096,China)

机构地区：[1]东南大学岩土工程研究所,江苏南京210096

出　　处：《岩土工程学报》2020年第2期354-361,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51578146,51778138);江苏省研究生科研与实践创新计划项目(KYCX18_0106)。

摘　　要：土体热导率是能源地下工程、高压电线埋设、冻土路基等工程设计中的重要参数,是评估土体换热性能及地下温度场计算的关键,但目前缺乏有效的原位测试手段。基于瞬时线热源温度消散理论,研发了可测试原位土体热导率的静力触探(CPT)探头。根据理论假设与现有CPT系统尺寸,确定了探头具体长度、直径、内部构造、温度采集点位,并提出相应测试步骤与热导率计算方法。利用COMSOL有限元分析软件对测试过程进行模拟验证,结果表明探头实际传热符合线热源假定,且计算方法适用于一般热导率土体。对于热导率较小(小于0.6 W/(m·K))土体,需适当延长测试时间。现场应用表明,土体原位热导率略高于取样土室内测试结果,表明取样扰动可能降低土体导热性能,最后对取样测试及工程设计提出改进建议。The thermal conductivity is the key parameter to the design of many projects, such as energy structures, high-voltage buried power cables and permafrost embankment, related to estimating the heat transfer capability and temperature field in the soil. However, at present there is no effective in-situ testing method. Based on the theory of instantaneous heat release along a line source, a heat conduction cone penetration test(CPT) probe for thermal conductivity evaluation of in-situ soil is developed. According to the theoretical assumptions and the sizes of CPT system, the length, diameter, internal structure and positions of the temperature sensors are introduced. Then, the corresponding test procedure and the method for thermal conductivity are proposed. The test process is simulated in COMSOL to verify the method, and the results validate that the actual heat transfer conforms to the line source theory. The interpretation method yields reasonable values within a general range of conductivities. For less conductive soil(<0.6 W/(m·K)), longer duration of heat dissipation may be required. The field test results show that the in-situ soil conductivity is higher than that from laboratory tests on undisturbed samples, indicating the sampling disturbance may be responsible for this reduction. Finally, some suggestions on laboratory thermal conductivity tests and engineering designs are given.

关 键 词：热传导探头 土体 热导率 计算 原位测试方法 现场测试 

分 类 号：TU473.1[建筑科学—结构工程]