Author(s)

V. Doležel & P. Procházka

Abstract

The phenomenon known as bumps or rock bursts are one of the greatest dangers to human health during mining operations. They are caused by the accumulation of energy of forces (stresses) in close vicinity to a face of excavations of seams. This causes a sudden release of energy, which is strongly dependent on a development of material properties in both rock overburden and coal. In this case the coal material behavior can be neglected as for the time development. Hereditary problems have to be taken into account, as velocity of excavation is one of the biggest problems in this field of research. The faster the velocity is, the shorter time for redistribution of forces can be reached. This causes a more dangerous situation, as for the bumps initiation. These ideas are valid for pure openings, but not for wall reinforcement during mining, support of the ceiling of mines, etc. These additional elements also have to be taken into account, but not in this paper. We are concentrating only on time dependency of redistribution of stresses in the vicinity of seam face. Keywords: rock bumps, coupled modeling, certain time-dependent problems, bumps on dislocations, physical scale modeling, numerical solution. 1 Introduction In the paper, a time-dependent contact problem is formulated and solved. The main application is focused on the field of geomechanics, namely on bumps occurrence in deep mines. The time factor, which plays decisive role in the solution of the problem of bumps, depends on wide scale of circumstances. One of the most important items describing the sudden failure of the rock, i.e. influencing the real behavior of the rock, and consequently leads to the bumps

Keywords

rock bumps, coupled modeling, certain time-dependent problems, bumps on dislocations, physical scale modeling, numerical solution.