Study on hydro-mechanical coupling properties of clay rock in Tamusu - the pre-selected area of high-level radioactive waste repository

Abstract

Abstract The research of hydro-mechanical coupling properties is of great significance for the design of high-level radioactive waste repository. In this paper, the permeability evolution test of Tamusu clay under full stress-strain condition is carried out. Based on the basic theoretical equation of hydro-mechanical coupling, the relationship between the permeability and stress of the Tamusu clay is analyzed. Combineed with the results of in-situ stress measurement in the Tamusu area, the excavation simulation of the roadway with a burial depth of 500 m in the area is carried out, and the change law of pore water pressure in the surrounding rock near the field is analyzed. The results show that when the osmotic pressure is constant, the peak strength increases and the permeability decreases with the increase of confining pressure. When the confining pressure is constant and osmotic pressure increases, the result is reversed; The permeability of Tamusu clay is affected by confining pressure more than the osmotic pressure, and the relationship between permeability and axial stress follows the negative exponential function.