A new method of mining pressure control for roof cutting in advance working face

Abstract

After the extraction of deep coal resources, the original stress state is disrupted, leading to increased abutment stress ahead of the working face. This heightened pressure causes significant deformation in the roadway preceding the working face. To tackle this issue, a pioneering method called Roof Cutting in Advance of the Working Face(RCAWC) has been introduced to mitigate deformation by proactively alleviating pressure. This method leverages the principle of conservation of energy within the rock mass system, augmenting the fragmentation energy of the roof rock mass through controlled blasting. This process aims to release the accumulated energy within the rock mass, thereby reducing pressure. This research not only elucidates the mechanism employed by RCAWC to counteract mining pressure but also delineates the evolving pattern of bearing pressure at various RCAWC heights. The findings reveal a shift in the abutment stress curve from a single-peaked to a double-peaked pattern after roof cutting. Notably, there is a significant reduction in abutment stress as the RCAWC height increases. However, as the thick roof is cut off, the negative correlation effect diminishes. Subsequently, an engineering implementation was carried out. Following the adoption of RCAWC technology, roadway deformation decreased by 63.6 % to 75 %, and the size of the protective coal pillar reduced by approximately one-third. These findings underscore the remarkable effectiveness of RCAWC technology in impeding the propagation of mining pressure towards roadways, reducing the extent of abutment stress, and ultimately alleviating stress and deformation within the surrounding rock formation.