Calculation of displacements and deformations in rock mass with regard to field data

The maximal vertical displacements and deformations (subsidence, inclination, curvature) in the layers of undermined rock mass are related with the combinations of undermining degree factors per sections across and along the strike of a mineral bed are determined. The relationships are plotted using the algorithms of calibration curve. From the analysis of possible combinations of undermining degree factors, six schemes are obtained, and each scheme images the correlation of the maximal vertical displacements and deformations generated at two different levels (horizons) in rock mass. Prediction of vertical displacements and deformations needs that their distribution is known at one level. This is achieved via laying a profile line on ground surface, monitoring of verticaldisplacements of checkpoints in the line, and obtaining patterns of subsidences, inclinations and curvatures on this basis. In some events, the profile line may be laid in development entries driven in rock mass above the mined-out space. At the other level, with possible undermined underground openings, aquifers or any layers of undermined rock mass, it is possible to determine their maximal vertical deformations using the obtained relationships, which is demonstrated. By analogy with prediction of vertical deformations, it is possible to determine a distance between a stope and a layer with the preset deformation. The layer adjoining the upper boundary of the water-conducting fracture zone (WFZ) is functionally connected with the curvature called the limit curvature which is determined in each specific case as a function of clay rock content and distribution of rock layers across the thickness of undermined strata. Therefore, using the obtained relationships, it is possible to find a distance between a stope and a layer with the limit curvature, and this layer is intrinsically the height of WFZ. The latter is required for the ascertainment of safety of mining under water bodies.