Theory on Determining the Stress in Rock Unaffected by Boreholes or Drifts

Abstract

The present paper describes the results of theoretical investigation into determining the stress in the rock unaffected by boreholes or drifts from the strains or deformations measured in those openings. It is pointed out that when the stress in the rock is determined from variations in borehole diameter or from strains on the bottom surfaces of boreholes, measurement should be made at least in three boreholes, while we can determine the stress in the rock from strains on the wall surface of at least either a boreholes or a drift, or from deformation of a borehole. For all cases the formulae to be used in practice for determining the absolute stress in the rock are presented and the accuracy in the stresses obtained by these formulae is discussed.