Research on the stability mechanism and control technique of surrounding rock in gob side entry driving.

Abstract

In order to enhance coal resource recovery and improve the stress environment of roadway surrounding rock, the practice of gob-side entry driving (GED) has been applied in China. Despite its numerous advantages, the presence of relatively narrow coal pillars poses significant safety concerns, especially with regard to the fracture of the main roof, which can lead to pillar failure and roadway instability. This study took the 15107 tailgate in Wenzhuang Coal Mine as the research object, and carried out a series of studies. Firstly, based on the theoretical framework of the block beam theory for lateral roof fracture, the influence of different fracture positions of the main roof on the stability of the gob side roadway is analyzed. Subsequently, a numerical model using UDEC Trigon was established to analyze the impact of main roof fractures in four different scenarios on the stability of the roadway surrounding rock. The results indicated that when the fracture line is positioned directly above the edge of the gob, the stability of the roadway is optimal. Furthermore, a hydraulic fracturing (HF) roof-cutting technology, based on manual intervention, was proposed to actively sever the main roof and facilitate stress transfer. The field application of this technique yielded significant improvements, with a reduction in roadway deformation of over 30%.