Bearing characteristics and safety control of hydraulic support groups in shallow-buried thin bedrock ultra-long working faces

Abstract

To explore bearing characteristics of hydraulic support groups in shallow-buried thin bedrock ultra-long working faces, a beam-on-elastic foundation (BEF) mechanical model was established for the coal walls, supports, and roof of the working face. The influence of seven factors on the resistance of the supports was investigated. The theoretical calculation and the actual measurement are in good agreement. Results show that working resistance of supports is distributed in two patterns: single-peak and M-shaped three-peak forms. The working face length and main roof thickness and elastic modulus have influence on the shape of the resistance distribution curve and the range of high support resistance. The mining height and overlying strata load affect the value of the curve. The support stiffness affects the range of high resistance. The roadway sidewalls stiffness affects the support resistance near the roadway side. Based on this, key safety control measures for shallow ultra-long working faces with thin bedrocks including determination of appropriate working face length, zonal regulation of supports, cooperative control of coal walls, and active reinforcement of roadway sidewalls were proposed. The research results provide a theoretical basis for design of support resistance and disaster prevention in shallow ultra-long working faces with thin bedrock.

Keywords

mining / rock mechanics / ultra-long working face / support resistance / safety control of working face / disaster prevention

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