INFLUENCE OF ROCK INTERFACE ON STRESSED STATE OF MINE SUPPORT SUBJECTED TO SEISMIC ACTION

Abstract

The methods estimating the stressed state of underground structures under seismic action of earthquakes and taking
into account reflection and refraction of seismic waves at the interface of rocks with different deformation properties are proposed. The methods are based on an analytical solution of the plane pseudo-static elasticity theory problem on stressed state of the ring supporting an opening near the interface of two half-planes. The half-plane with the opening is loaded at infinity and along straight boundary by stresses found from known solution of the dynamic problem on reflection and refraction of plane harmonic waves at interface. Solution of the problem has been obtained with the help of complex analytical functions theory, cauchy type integrals and complex series. The solution is reduced to an iteration process specifying interface
influence on every step of approximation. The favourable conditions for growth of stress amplitudes at the interface
and stresses in an underground structure are discovered. The dependencies of stress amplitudes on wave incident
angle have been obtained. The design results obtained for a circle opening support are compared with the data received by the standard technique. The developed methods permit to find the possibility of significant i seismic load increasing on the underground structure located near the rock interface. It is proposed to apply the approach used for the design of non-circular shape supports and shallow underground structures.