The stress state of rock with an excavation and load-removing slits

Abstract

We propose a method of determining the stress state of an anisotropic rock with an excavation, including the case in which there are load-removing slits extending to the surface. In cross section the excavation can have an arbitrary curvilinear outline. The rocks have any rectilinear anisotropy, and may have planes of elastic symmetry with an arbitrary inclination to the horizontal plane. The method is based on solving the two-dimensional problem of the theory of elasticity of an anisotropic body using generalized complex potentials, conformal mappings, and the method of least squares. The problem is reduced to solving a system of linear algebraic equations in the unknowns that occur in the complex potentials. We carry out detailed numerical studies on the distribution of stresses and lowering their concentration around the excavation by setting up a system of load-removing slits.

The proposed method of studying the stress state of rocks around an excavation both with and without slits and makes it possible not only to establish the zone of high stress concentration, but also to choose the optimal combination and location of load-removing slits. Its application by specialists in the coal industry will make it possible to establish the stability of excavations taking account of their geometric parameters and the depth, length, and location of the load-removing slits, and the physico-mechanical characteristics of the rock. Five figures. One table. Bibliography: 6 titles.