Rationale and modeling of technology for complex bottom-hole zone de-stressing of gas-dynamically active rock mass

Abstract

Purpose. The research aims to substantiate the geological principles and peculiarities of modeling complex de-stressing of a stressed bottom-hole mass during the construction of mine workings at depths of more than 1000 m. Methods. A comprehensive research methodology is proposed, which consists of conducting a computational experiment for calculating a complex de-stressing scheme and analyzing the stress-strain state (SSS) of the bottom-hole mass in the most informative mine working cross-sections, conducting experimental studies on the effectiveness of the method using the developed methodology for observing rock pressure manifestations and estimating energy consumption on the tunneling face rock destruction. Findings. A combination of two methods for de-stressing a rock mass adjacent to the tunneling face using advance slots has been substantiated. A geomechanical model has been created that takes into account the specifics of the proposed method. The stress-strain state of the rock mass adjacent to the tunneling face has been calculated in a series of cross-sections and longitudinal section of mine working. Originality. Three geotechnological principles of simultaneous de-stressing of both rocks adjacent to the face and rocks within the mass along the mine working route has been formulated and elaborated, embodied in the construction of a geomechanical model of complex adjacent rock mass de-stressing. Based on the obtained stress-strain state, five positions of have been developed for complex consideration of changes in the distribution fields of determining stress components. The methodological principle for assessing energy consumption for rock destruction has been substantiated, and an evidence base has been created to confirm the advantages of the proposed mine working construction technology at depths above 1000 m in a gas-dynamically active rock mass. Practical implications. The method for complex de-stressing the rock mass adjacent to the tunneling face, using pre-drilled wells and de-stressing slots, is proposed. Experimental studies confirm the proposed method feasibility in three directions for safe and resource-saving construction of mine workings in a gas-dynamically active rock mass at great depths. Calculations have proven that energy consumption for bottom-hole rock destruction has decreased in the range of 15-26%.