Integrated numerical and block modeling for the stress–strain assessment of mine shafts

This article examines a methodology for the comprehensive stability analysis of vertical mine openings and shafts based on the combined use of the geomechanical block modeling and numerical modeling. The focus is on constructing a numerical model that imports the physical and mechanical properties of rocks determined using a geomechanical block model (GBM). This approach provides a detailed spatial distribution of parameters with regard to the lithological differences, fracturing zones, tectonic faults, and the complex geometry ofadja cent mine openings. The subject of study was a mine shaft and two closely spaced ore passes where damages of concrete lining were recorded in the depth interval between -450 and -550 m. According to the inspection results, the damages represent local falls and nonuniform deformations, which points at the high stress gradients and structural nonuniformity in rock mass. The actual data inform on the complex geomechanical conditions in the test area, due to the combination of faulting, contrasting lithology and closeness of the ore passes which add to loading redistribution. The study included the stress–strain modeling of rock mass to assess the impact of weakened zones and process openings on the stability of the lining support. The obtained results indicate that the use of the average rock mass properties leads to a significant distortion of the stress pattern, while integrating the data in the geomechanical block model allows reproducing the actual spatial distribution of the physical and mechanical properties which have a decisive influence on the complex local stress–strain reconstruction. The proposed approach improves the calculation accuracy, aligns the calculated stress concentration zones with the actual deformation and failure patterns, and expands the ability to predict rock mass behavior during support repair and new vertical opening design.