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 pre sented for the analytical and numerical solution of corresponding problems of geomechanics, on the basis of which regularities governing the subsidenc e of the daylight surface, roof deflection, and floor rise, and variations are also established for the parameters defining zones of vertical and hori zontal stresses above the working. The boundaries of shallow depths in rela tion to the span length of working with hanging up roof are determined wher e regularities of the undermined strata displacement and stress distributio n differ in essence from corresponding regularities at great depths.