Ural State Mining University, Yekaterinburg, Russia:

O. G. Latyshev, Professor, Doctor of Engineering Sciences
D. V. Prishchepa, Assistant, prischepadv@yandex.ru

Stability of underground excavations is based on prediction of the rock mass stress–strain behavior. Regarding fractured rock mass, this problem has no unambiguous solution and requires special research to be undertaken. This study aims to develop the stress–strain behavior prediction procedure for fractured rock masses of block structure based on the statistical modeling of the excavation–rock mass system. Prediction of the stress–strain behavior of rock mass is carried out using the finite element method. Setting of the initial conditions for the method implementation software requires consideration of characteristics of the fracture network in rock mass. The article presents the assessment procedure of the stress–strain modulus and dilatancy of rocks based on the fractal analysis of fracture propagation in the course of rock mass deformation. The application of the finite element method is illustrated in terms of the stress–strain analysis of rock mass in the Yubileinoe field (Bashkortostan) in the course of horizontal tunneling. Stress concentration at the excavation boundary is estimated by defining its fractal shape factor with regard to the ratio of the project cross-section area to the perimeter of excavation during heading. The estimate of joint operation of mine support and rock mass takes into account the time factor by determining the influence of creep on the stress–strain modulus of rock mass. The obtained result is used as a framework for the stress–strain behavior prediction in fractured rock mass around underground excavations and for the stable support design.

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