INVESTIGATION OF CAVERN DISTORTION IN THE GORDON UNDERGROUND POWER STATION, TASMANIA

摘要

It can be concluded that the observed deflections of the crane rails and the observed tilts of the number one and two machine axes can be explained in both magnitude and direction by a reduction in the modulus of the rock surrounding the cavern when subjected to an inclined principal stress field. The rock stresses and rock modulus required to explain the magnitudes of the observed deflections are generally consistent with values measured at the time of the cavern excavation. The directions of the observed movements are consistent with the expected inclination of the principal rock stress field at the power station site due to the effect of the nearby steep topography. It is considered reasonable to attribute the rock modulus reduction to the development of time dependent creep strains in the rock surrounding the cavern.