Assessment of contour deformations of reused mine workings

Introduction. In conditions when the thickness of the mined seam does not allow to form the required cross-sectional excavation without cutting of the host rocks, it is advisable to apply technological schemes with reuse of preparatory workings. Research in the field of development of effective ways to assess the stability of reused preparatory workings in such conditions of bedding of seams at present remains relevant, including for the mines of the Pechersk Coal Basin. The task of the described research is to obtain a picture of changes in the stress-strain state of the geotechnical system under consideration and to estimate the displacement values of the near-contour areas of the preparatory mine workings at different positions of the face.

Materials and methods. Were used to carry out numerical experiments using the finite element method in the Midas GTS NX software package for the conditions of one of the operating mines in the Pechersk coal basin. The Coulomb – Mohr criterion was used to describe changes in the geomechanical state of the mining system. To assess the reliability of simulation results, comparisons were made with instrumental measurements of geometric parameters along the length of workings.

Results. During the simulation, the spatial distributions of the resulting deformations in the geomechanical system under consideration were obtained. The estimation of the magnitude of displacements in adjacent areas of preparatory mine workings was made as the face moved. The calculated values of vertical and horizontal displacements allow us to assess compliance with the requirements for fastening and protecting workings, as well as design specifications for the mining area. These values can be used to evaluate the effectiveness of decision-making. The results of model calculations are supported by data from mine instrumental observations.

Conclusions. The results of the study demonstrate that the proposed geomechanical model of rock mass fully reflects the main features of its structure and changes in the contours of preparatory mining operations during its operation and can be used to assess the effectiveness of various methods for maintaining it during reuse.

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