Известия Томского политехнического университета: Инжиниринг георесурсов (Jul 2019)
GEOMECHANICAL SUBSTANTIATION OF THE PARAMETERS OF STABLE CHAMBERS AND PILLARS IN COMPLEX MINING AND GEOLOGICAL CONDITIONS
Abstract
The relevance of the research is caused by the necessity of ensuring safety at the Sokolovski underground mine, as well as improving the completeness and quality of excavation of resources in complex mining and geological conditions – in the presence of a covering layer of watered loose sediments. The aim of the research is to determine the optimal parameters of stable chambers and pillars to prevent rock collapse and penetration of sandy-argillaceous deposits into underground excavations. The object: the rock mass in the Northern area of Sokolovskoe deposit. Methods. Multivariate numerical modeling with the finite element method in a two-dimensional approach was performed in the Rocscience RS2 software, which allowed taking into account a large number of factors affecting the state of the massif. The calculations included not only the physical and mechanical properties of rocks and the acting stresses, but also the structural characteristics of the rock mass, as well as the level of technogenic impact. As a model of the massif behavior, the Hoech–Brown model was used, which distinctive advantage is nonlinearity. Since the real rock mass is characterized by heterogeneity of the strength properties and the stress-strain state, the probabilistic analysis provided in the Rocscience software was implemented, taking into account the variations of the boundary conditions within the established intervals for the created model. As a result of numerical simulation, a change of the stress-strain state of the massif was determined, on the basis of which the safety factor of the surrounding rock mass was calculated, as well as the magnitudes and directions of its displacements, and also zones of distribution of the massif destruction probability within the given intervals of boundary conditions were established. The parameters of the chambers and pillars which ensure the overall stability and minimize the possibility of breaking mud water into the workings were determined. Conclusions. Maintaining the stability of the roof of the underground chambers while stopping ore blocks at the Sokolovskaya mine will enable to reduce the risk of sandy-argillaceous deposits penetration into the underground openings, ensuring safe and efficient mining, and also to improve the completeness and quality of resources excavation. The multivariate numerical modelling of the influence of mine openings on the rock mass made by the finite element method allowed determining the optimal geometric parameters of chambers and pillars that ensure the stability of the surrounding massif. Application of the Rocscience RS2 software due to accounting a large number of factors affecting the state of the massif significantly improves the reliability of rock mass stability assessment.
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