IN SITU STRESS- MEASUREMENTS BY HYDRO - FRACTURING - SOME CASE STUDIES

Abstract

Rock masses are initially stressed in their natural state. For the stability of artificial subsurface structures knowledge of the in-situ or virgin stress field is needed to predict the response of rock masses and to the disturbance associated with those structures. In-situ stresses are used for stress-deformation analysis, in design of underground structures for site location, selection of orientation, selection of shape, dimensioning, excavation sequence, support, rock reinforcement etc. In civil and mining engineering, in-situ stresses control the distribution of stresses around underground cavities. These stresses may be large enough to mobilise the strength of the rock mass and cause failure.- Previously, modulus of deformation and shear strength parameters only were measured. However, the state of stress is one of the crucial parameters which in recent years has been included.....