Coupled Thermo-Hydro-Mechanical Effects on Transport Properties of Glacial Tills

This study is focused on the experimental investigation of the coupled thermo-hydro-mechanical effects on transport properties of clayey soils. Glacial till specimens collected from a borehole at the University of Illinois at Urbana-Champaign (UIUC) campus were subjected to the effective mean stresses at their corresponding depths and the thermal gradient typical for a shallow geothermal system. The experimental results indicate the increase in permeability of glacial tills with temperature, mainly pounced for shallower specimens. The changes in material properties and dilation/compaction of normally consolidated tills are considered in the constitutive model that allows calculating the changes in porosity due to applied thermo-hydro-mechanical loading. The power law porosity-permeability relationships for glacial tills at different temperatures are established and indicate porosity sensitivity exponents' values of approximately 15-similar to those for claystones.