摘要
提升地埋管钻孔回填材料的导热性能是提高地埋管钻孔换热效率的重要方式。文章以粉砂、细砂和中砂为地埋管回填基料,添加不同质量分数的重晶石粉和水泥膨润土,配置高导热回填材料,通过对比实验数据,并考虑回填材料配制的经济性,探讨不同岩性条件回填材料的适用性。实验分别在基料中添加质量分数2%、4%、6%、8%和10%重晶石粉,并按照砂:水泥:膨润土质量比为3∶1∶0.5的配比制备水泥膨润土砂浆,共配制饱水高导热回填材料样品18件,进行热导率测试。结果表明:砂土地层中适宜采用中砂配比质量分数6%的重晶石粉作为地埋管钻孔回填料,砂土粒径减小时,重晶石粉含量应相应增加;岩石地层中,建议采用水泥膨润土砂浆等易凝固高导热的回填材料代替砂土回填料,且基料应选择粒径较大的砂土。
Enhancing the thermal conductivity of backfill materials for buried pipe drilling is an important way to improve the heat exchange efficiency of buried pipe drilling.In this paper,high-thermal-conductivity materials are prepared by proportioning the backfill base materials of silty sand,fine sand,and medium sand for buried pipes.Barite powder and cement-bentonite are selected.Considering comprehensively the heat exchange efficiency and economic applicability of the prepared backfill materials,the applicability of backfill materials under different stratum conditions is studied.The base material is proportioned with 2%,4%,6%,8%and 10%by weight of barite powder respectively,and cement-bentonite mortar is proportioned at 3∶1∶0.5.A total of 18 saturated high-thermal-conductivity backfill material samples are prepared for thermal conductivity tests.The results show that:in sandy strata,it is appropriate to use medium sand proportioned with 6% barite as the backfill material.When the particle size of sandy soil decreases,the content of barite powder should be increased accordingly.In rock strata,it is recommended to replace sandy backfill materials with cement-bentonite mortar and other easily set high-thermal-conductivity backfill materials.And larger-sized sandy soil should be selected as the base material to improve thermal conductivity.
作者
邢罡
王任博
许真瑞
李娟
XING Gang;WANG Renbo;XU Zhenrui;LI Juan(Beijing Geothermal Research Institute,Beijing 102218,China;Key Laboratory of Shallow Geothermal Energy,Ministry of Natural Resources of the People’s Republic of China,Beijing 100195,China)
出处
《城市地质》
2025年第2期253-258,共6页
Urban Geology
基金
热渗耦合作用下地埋管换热器传热特性研究项目(11000023T000002056332)资助。
关键词
回填材料
热导率
地埋管
地源热泵
重晶石粉
水泥砂浆
backfill material
thermal conductivity
buried pipe
ground source heat pump
barite powder
cement mortar
