Применение численного и блочного геомеханического моделирования для определения параметров крепления камерных выработок большого сечения

Abstract

The study is exemplified by complex workings of a main ore pass that include a variety of underground structures, usually with unique dimensions which depend on the function and size of the equipment placed. The technical solutions for the underground crushing plant and associated structures envisage construction of chambers with the height of up to 35 m and the width of up to 20 m at the depths exceeding 800-1000 m. Such conditions call for a closer attention to be paid to the mine support parameters, especially the bolting depth. A block geomechanical model was designed in the Micromine Mining Software for the rock mass of the new main ore pass. Geotechnical boreholes logs and results of physical and mechanical rock tests were used as the input data for the model. Four domains were identified in the block geomechanical model for subsequent numerical modelling. A 3D model of the stress-and-strain state of the rock mass was made using the CAE Fidesys software based on the Micromine wire-frame model of the main ore pass. The history of the rock mass incremental loading was reconstructed for correct simulation of its stress-and-strain state. Prior to the excavation, the rock mass is pre-stressed by the weight of the rock strata. The excavation phase was then simulated in the stepwise manner. An array of points with the values of maximum principal stresses was downloaded from the numerical model post-processing program and interpolated into the block geomechanical model to refine the SRF parameter of the Barton's Q rating. Based on the obtained Q values, the mine support parameters for chambers were determined using the Barton, Hutchinson and Potvin empirical methods.