Pre-mining state of stress

Abstract

The design of an underground structure in rock differs from other types of structural design in the nature of the loads operating in the system. In conventional surface structures, the geometry of the structure and its operating duty define the loads imposed on the system. For an underground rock structure, the rock medium is subject to initial stress prior to excavation. The final, post-excavation state of stress in the structure is the resultant of the initial state of stress and stresses induced by excavation. Since induced stresses are directly related to the initial stresses, it is clear that specification and determination of the pre-mining state of stress is a necessary precursor to any design analysis.