Geomechanical prediction of growth of brittle fracture zones in the vicinity of underground excavations in over-stress rock mass

The theoretical and applied research data on formation of brittle fracture zones in over-stress rock mass are reviewed. The mathematical modeling of the related processes is discussed. It is shown how geomechanical processes develop up to formation of a brittle fracture zone. The latter can be described using the deformation models formulated within the theory ofplastic flow, with strength characteristics determined as functions of plastic strains of (hardening/softening law). Based on the mathematical modeling, prediction of brittle fracture zones at junctions of underground excavations of different geometry is implemented. It is found that the geometry of junctions and excavations has influence on the size of the brittle fracture zone. The relationships of change in the brittle fracture zone size versus effective stresses and characteristics of rock mass are generalized in the form of an analytical dependence. The research results are used in design of support systems for underground openings in over-stress rock mass (massive and weak or heavily jointed).

Korchak P. A. Geomechanical prediction of growth of brittle fracture zones in the vicinity of underground excavations in over-stress rock mass. MIAB. Mining Inf. Anal. Bull. 2021;(5):85-98. [In Russ]. DOI: 10.25018/0236_1493_2021_5_0_85.

P.A. Korchak, Head of the Forecast and Prevention of Mountain Impacts Service, Kirovsk Branch of Apatit, 184250, Kirovsk, Russia, e-mail: pkorchak@phosagro.ru.

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