Behavior of Soils Subjected to Thermo-Hydro-Mechanical Coupled Actions

Abstract

Coupled Thermo-Hydro-Mechanical (THM) analyses involving soils and rocks are becoming increasingly more popular because of the need to develop infrastructure under every time more challenges ground conditions, as well as, due to the expansion of geochemical engineering to applications involving complex geo-environmental and geo-energy problems. This dissertation focuses on three research topics involving the coupled THM behavior of soils: 1) Experimental and constitutive studies of frozen soils subjected to freezing-thawing (F-T) cycles. The behavior of soils is investigated in the lab by under controlled environmental conditions, which are mainly focused on the volume change response of soils subjected cyclic F-T actions. Also, a new and comprehensive constitutive model for soils subjected to F-T cycles is proposed. 2) Constitutive mechanical modeling of hydrate bearing sediments (HBS). An advanced elastoplastic model is proposed to capture the complex response of this type of soil when subjected to THM interactions. The proposed approach includes inelastic mechanisms to account for the following effects, amongst others: soil and hydrates structure; temperature; dilatancy; and time-dependent behavior. 3) Experimental study on gas migration phenomena through clay-barrier systems intended for the safe isolation of high-level nuclear waste. The investigation looks at effect of soil suction, and swelling pressure on gas permeability This work also investigates the effect of cracking and self-healing on gas flow characteristics.

The underlain aim of this project is to gain a better understanding of soil behavior under these complex multiphase conditions to progress current knowledge in these three very relevant and timely subjects.