土样类型对非饱和土壤热湿迁移的影响研究

A Study on the Effect of Different Soil Types on Heat and Moisture Transfer in Unsaturated Soil

为研究不同土样类型对土壤热湿迁移规律的影响,搭建了一维土柱实验台,选取砾砂、粗砂、中砂、细砂、粉砂、黏土6种土样类型作为研究对象,分别进行了热湿迁移规律的实验研究。实验结果表明:在初始含水率为5%、热源温度为30℃、击实功为20J实验工况下,6种土样在加热过程中热迁移表现出差异性,粉砂、细砂和黏土热迁移效果最佳,砾砂和粗砂次之,中砂热迁移效果最差。在热影响半径内,土体中热量的传导与含水率的传递相互作用,互为驱动:愈靠近热源,温度梯度愈成为水分在土样中运移的主要驱动力;愈远离热源,湿度梯度愈成为温度传导的主要驱动力。得到的不同土样类型在热湿迁移规律上的差异性及非饱和土样热湿迁移驱动机理可以为解决工程中所遇到的不同土质热湿迁移问题提供一定的参考依据。

In order to study the effect of different soil types on heat and moisture transfer, a one-dimension soil column experimental platform is constructed, and 6 kinds of soil samples, such as gravel sand, coarse sand, middle sand, fine sand, silt and clay, are selected to study the rules of heat and moisture transfer. The experimental results show that： under the condition of the initial water content of 5%, the heat source temperature of 30℃ and the compaction work of 20J, there are some differences for heat transfer in 6 kinds of soil samples during the heating process; the silty sand, fine sand and clay have the best heat transfer effect, the second is the gravel sand and coarse sand, and the heat transfer effect of the middle sand is the worst; in the heat-affected radius, the conduction of heat in soil and the transfer of water content are mutually driven; the closer the monitoring point to the heat source, the more the temperature gradient becomes the main driving force for the migration of water in soil samples, and the farther away from the heat source, the more the humidity gradient becomes the main driving force of the temperature conduction. The difference of the heat and moisture transfer of soil types and the driving mechanism of heat and moisture transfer in unsaturated soil can provide some reference for solving the problems of heat and moisture transfer in different soils.