Coupled thermal-hydro-mechanical model of deep artificial freezing clay: Fid-Bau Portal

Coupled thermal-hydro-mechanical model of deep artificial freezing clay

Yang, Yugui / Lei, Dawei / Chen, Yong / Cai, Chengzheng / Hou, Shanshan

Abstract The research on the thermal-hydro-mechanical coupling theory is important to explore the freezing mechanism of deep shaft. It is difficult to accurately describe the moisture migration and law of frost heaving characteristics of the clay during the freezing process. In this study, a thermal-hydro-mechanical formulation is established to simulate the freezing process of soil according to the dual-porosity medium approach. The reasonability of the coupling model is verified by the comparisons of the calculated results with the model and field tests. It is indicated that the moisture migration can be represented by the combination action of the matrix and fracture permeability during the freezing process. As the freezing time increases, the permeability of freezing clay decreases greatly, the moisture gathers around the freezing pipe, and a high frost heaving stress is formed close to the freezing pipe due to the moisture migration. Then, the temperature evolution, the moisture migration and the frost deformation of frozen soil wall are investigated to explore the freezing mechanism of deep shaft.

Highlights • The micro-structure characteristic of clay is obtained by the MIP and SEM experiments. • The migration mechanism of moisture relying on the fracture and matrix seepage is analyzed. • A dual-porosity THM coupling model is established for freezing clay. • The temperature, stress and frost fields of mining shaft is analyzed.