Numerical simulation of cement grouting of saturated soil during a mine shaft sinking using the artificial ground freezing

摘要

Cement grouting is widely applied in geotechnical engineering to reinforce water saturated soil and to control groundwater. The present paper is devoted to a numerical study of cement grout injection in a soil stratum during a construction of a vertical mine shaft using the artificial ground freezing (AGF) technology. For the study a thermo-hydro-mechanical model was developed. The governing equations of the model are derived based on the theory of porous media. The model takes into account the features of AGF and grouting processes such as a non-Newtonian behavior of cement grout flow, water-ice phase change and an influence of pore pressure and temperature on an evolution of a stress-strain of the soil. Three-dimensional numerical simulation of cement grouting of unfrozen soil between the shaft lining and the ice-soil wall was conducted using the model for various injection regimes. Results of the simulation have shown that the grout injection leads to a rise in temperature and volumetric strain in the soil. A mechanical impact of the injection procedure on the shaft lining is an increase in the mechanical pressure near the injection boreholes and a redistribution of the von Mises stress.