Thermo-hydro-mechanical behavior of an embankment thermal storage

Abstract

In geotechnical engineering, thermal energy storage in embankments can be considered as a new economically efficient, and environmentally friendly structure for space heating. In these structures, horizontal heat exchanger tubes could be installed inside the different layers of compacted soil to store the heat in the medium during the summer, to be extracted in the winter. Seasonally temperature variations caused by heat exchangers can affect Thermo-Hydro-Mechanical (THM) properties of the compacted soil in the embankment. Both the short and long term behavior of this compacted soil should be investigated. The aim of this study was to investigate the effect of temperature variations in the range of 5° to 50 °C, on THM behavior of a compacted sandy lean clay in saturated state. To achieve this, temperature-controlled oedometric and direct shear tests were performed. The results showed that, the effect of the temperature on mechanical properties are more pronounced under a vertical stress higher than the yield stress. Heating changed the void ratio during consolidation phase but has a negligible effect on the shear characteristics. The results also showed that the cooling slightly changed the shear parameters.