Numerical simulation for influences of pressure solution on T-H-M coupling in aggregate rock

ZHANG Yu-jun(张玉军)¹ , JU Xiao-dong(琚晓冬)^{1, 2}

(1. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China;
2. Civil Engineering School, Henan Polytechnic University, Jiaozuo 454000, China)

Abstract:The pressure solution model of granular aggregates was introduced into a FEM code which was developed for the analysis of thermo-hydro-mechanical (T-H-M) coupling in porous medium. Aimed at creating a hypothetical model of nuclear waste disposal in unsaturated quartz aggregate rock mass with laboratory scale, two 4-year computation cases were designed: 1) The porosity and permeability of rock mass are functions of the pressure solution; 2) The porosity and the permeability are constants. Calculation results show that the magnitude and distribution of stresses in the rock mass of these two calculation cases are roughly the same. And, the porosity and the permeability decrease to 43%-54% and 4.4%-9.1% of their original values after case 1 being accomplished; but the negative pore water pressures in cases 1 and 2 are respectively 1.0-1.25 and 1.0-1.1 times of their initial values under the action of nuclear waste. Case 1 exhibits the obvious effect of pressure solution.

Key words:pressure solution; aggregate rock; thermo-hydro-mechanical (T-H-M) coupling; numerical simulation