Solution of the spatial problem of creep for a preparatory working

Abstract

In order to establish the effect of face advance rate on the rock mass stress-strain state, it is necessary to consider the spatial problem of creep theory in coal mining. The authors consider an isotropic uniform viscoelastic rock mass with a working of square cross section. The physical equation of state for a viscoelastic rock mass is presented in the form of a Boltzmann-Voltaire integral equation. Figures show the design diagram, the change in creep strain ahead of the face and in the roof, dependence of creep strain ahead of the face and in the roof on sandstone, argillite, and coal, and the dependence of creep strains on the rheological properties of rocks at different rates. It was shown that an increase in the rate of energy accumulation over the rate of its dissipation indicates that for some section of time in the rock mass energy accumulates more than it is released. The ratio between rates of dissipation and accumulation will govern the nature of rock failure; the less this ratio, the greater will be the dynamic form of the failure process.