S. V. Kuznetsov

Hydrodynamic Effect of Coal Seam Compression

With increase in rock pressure, local coal failure caused by stratal water redistribution between the cracks of different orientation is considered. For the seam compressed by enclosing rocks, the failure criterion is obtained; the characteristic features of crack growth are shown.

Formation of tension and delamination areas in a long excavation’s roof

The article discusses assessment of geomechanical state and behavior of roof rocks in a long excavation as the production heading is advanced. Initial conditions and propagation of growth conditions of delamination fractures have been found, including dynamic regime.

Anomalous Stress Fields in the Vicinity of Tectonic Disturbances in the Rock Mass

The problem on stress state of the rock masses with a section of slipping in the geological structural weakening was solved by the method of complex potentials. The features of stress distribution in the concentration and unloading zones are described. The conditions, under which the sections with reduced cohesion are potentially hazardous with respect to dynamic manifestations of rock pressure, are established.

Stresses and Displacements around Seam Section Mined-out along the Strike

A solution is given for the geomechanics problem of the plane stress state and displacements of the enclosing rocks around a seam section mined-out along the strike between two horizons. It is assumed that a roof hangs over the free mined-out space. In stating and solving the problem, additional stresses and displacements are presented as the sum of two components reflecting the effect of initial normal and tangential stresses independently of one another. The solution is written in explicit form by a single complex function.

Stress State and Failure of Seam Contacts with Enclosing Rocks in Driving a Stope

The features are considered for shear and normal stress concentration at the interface of enclosing rocks with a seam during its mining. The relations determining the parameters of support pressure zone depending on the seam occurrence depth, its dip angle, length of the mined-out section, lateral pressure coefficient, and the average specific weight of the overlying rocks are presented. Conditions of origination and character of shear failure manifestation on the contact between the seam and the rocks beyond the peak of support pressure are defined.

Basic regularities governing the subsidence of undermined rock strata and deflection of hanging up roof at shallow and great depths

The influence exerted by depth of seam mining on the displacements of rocks and the formation of zones of tensile stresses is studied. Results are presented for the analytical and numerical solution of corresponding problems of geomechanics, on the basis of which regularities governing the subsidence of the daylight surface, roof deflection, and floor rise, and variations are also established for the parameters defining zones of vertical and horizontal stresses above the working. The boundaries of shallow depths in relation to the span length of working with hanging up roof are determined where regularities of the undermined strata displacement and stress distribution differ in essence from corresponding regularities at great depths.