Design and application study of the key technical parameters of dense drilling for pressure relief in coal mine roofs: a case study

This is the authors' abstract. We don't add key points for this paper.

The lateral cantilever beam structure developed after hard roof workface mining can impose high stress on the adjacent roadway and coal pillar. As a result, the mining pressure of the adjacent roadway can drastically increase. In this study, the application of intensive drilling technology for roof weakening is examined in accordance with the principle of large and small structures of the surrounding rock. The mechanism of stress correspondence and the characteristics of the plastic area distribution around circular holes of different diameters are analyzed. A numerical model is developed using block discrete element calculation software (UDEC) considering the geological conditions of the 31,315 workface in the Chahasu Mine, and the effects of the height and angle of the roof cut on the collapse characteristics of the workface lateral cantilever structure and the mining pressure distribution in the roadway are investigated. As indicated by the study results, in a certain range, with increasing height and angle of the roof cut, the roof more significantly collapses and fills the goaf, contributing to roadway stability. As revealed by the field test results, dense drilling precracking can promote timely roof collapse, reducing the roadway stress level and ensuring roadway stability.