| Abstract |
Due to varying thermal conditions in the ground, the local water content changes and consequently hydraulic and thermal properties change as well. It is important to make reliable forecasts of the thermal and hydraulic properties of the partially saturated soils for designing structures and constructions engaging thermal energy in the shallow ground. Resilient data of the hydraulic and thermal properties as a function of the water content is required for the simulation of changes in working conditions. Two experiments allowing for simultaneous determination of several hydraulic and thermal parameters at variable water contents of a sample were accordingly developed. The retention characteristics of a soil sample are determined in an evaporation test, while the unsaturated hydraulic conductivity and thermal conductivity as a function of the water content is measured simultaneously. By this experiment, primarily fine clastic, undisturbed soil samples are characterized during dewatering. Investigation of sandy soils is performed in a columnar experiment using frequency domain reflectometry sensors for the determination of the water content, tensiometers and thermal conductivity sensors at different levels of the sample. The soil samples in the column can be irrigated from the top and the bottom. These tests are currently a variety of experiments carried out to generate a statistically representative number of measurements on different soil types. To implement this data into FEM modelling, it is necessary to describe them by mathematical expressions representing the interdependence of water retention, unsaturated hydraulic and thermal conductivity. Actual various mathematical models are developed on the basis of this data and validated against the growing data set. |