Saint-Petersburg Mining University, Saint-Petersburg, Russia:

V. Yu. Sinegubov, Associate Professor, Candidate of Engineering Sciences
M. G. Popov, Associate Professor, Candidate of Engineering Sciences
M. A. Vilner, Post-Graduate Student, mary.vilner@gmail.com
R. O. Sotnikov, Post-Graduate Student

Introduction of new equipment in the production cycle in mines can greatly accelerate the pace of construction and can increase production output. And yet considerable time is spent on preparatory works, transport operations and shunting. To reduce the time consumption, engineers make nonroutine decisions on the arrangement of process equipment in underground excavations, which imposes certain requirements on their geometry and support design. For example, the design size of grinding chambers can exceed 14 m in height and 8 m in width. These dimensions are almost 2 times higher than the size stated in the regulatory documents. The mine support design guidelines are unadapted to the dimensions of such underground openings, and disregard the construction sequence, complicated geological and mining conditions, and the influence of stoping. As a result, geomechanical processes in the vicinity of large cross-section excavations in fractured rock masses can only be estimated approximately. This paper proposes a mathematical modeling algorithm including rock mass fracture intensity, the length/width ratio of a large cross-section excavation and the presence of junctions with other excavations. Such stress–strain analysis of tock mass provides the pattern of geomechanical behavior in the vicinity of the underground excavation, namely, it allows determining the change patterns of damaged zones in rock mass. It is shown that stoping can lead to an increase in the size of the limit state zones up to 3 times, which exceeds the safety factor as per the regulatory documents. The obtained results can widen the field of application of regulatory documents in mining.

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