Abstract
A finite difference method (Flac2D) and dimensional analysis have been applied to study a cavity developed through hydro-excavation of a mineral resource during borehole mining. The structural impact of differential internal fluid pressures on the cavity periphery has been numerically modeled. The research is focused on the effect of critical factors associated with the mining process on the largest principal stress in the rock (around the cavity roof). The goal was to observe the effect of cavity dimension, internal pressure (cavity pressurization), K (horizontal stress/vertical stress), vacuum (negative pressure), depth and method of extraction on the induced maximum principal stress. It was concluded that increasing internal pressure, cavity length, and depth of cover will significantly increase the induced maximum principal stress around the cavity. Applying negative pressure will cause stress concentration to move from roof of the cavity to the sidewalls and corners of the cavity. Increasing internal fluid pressure inside the cavity will increase the induced shear stress at the cavity roof corner.
