Mechanism of roof weakening by dense drilling and its application in non-pillar self-forming roadways

Abstract

The weak and broken roof, explosive control and other problems seriously restrict the promotion of non coal pillar self-forming roadway technology. In order to solve such problems, a new method of non coal pillar self-forming roadway through non-blasting roof cutting and pressure relief was proposed in this study. A systematic research system of “theoretical analysis-physical experiment-engineering verification” was constructed with the 9103 working face of Longmenta Coal Mine as the research object. Firstly, the theoretical analysis was conducted to reveal the roof cutting mechanics mechanism of rock mass weakened by dense drilling, establish the design criteria for key drilling parameters, and obtain the key design parameters of dense drilling in the test working face. Secondly, the physical model test was conducted to make clear that the dense drilling method can directionally cut off the goaf roof along the set position, reducing the stress and deformation of the roadway surrounding rock. Finally, the field engineering tests were conducted, and monitoring results showed that the pressure relief effect of the dense drilling method was comparable to that of the directional blasting method, achieving non coal pillar self-forming roadway mining under non blasting conditions.

Keywords

non coal pillar / weak roof / non-blasting / surrounding rock control / roof cutting and pressure relief

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