Development and Validation of a Double-Column Soil Cell for 1-D Heating Test

摘要

Recent developments of energy piles and soil borehole thermal energy storage have increased the concern of the behavior of soils under thermal loads. Laboratory heating and cooling tests of soils are subject to the ambient temperature effect due to inadequate thermal insulation. Thus, the test data are prone to errors due to such boundary effects. A double-column soil test cell was developed, and the test results of dry sand showed 1 -D heating was obtained in the inner soil column. In this study, the heat cell was modified that a hydronic heating exchanger was attached to the bottom of the column. The dry fine-grained sand was first tested to validate the measured temperature field with theoretical predictions. Then the coarse-grained sand was then tested to investigate its temperature performance. The results showed that both fine/coarse-grained sand can maintain 1-D heat transfer in the inner column cell. This test cell is promising to study the soil thermal and hydro behavior under controlled 1 -D thermal gradients.