Mechanism and surrounding rock control of gob-side entry formation passing through normal fault - A case study

Geological faults are widely distributed in stratum and have an important influence on underground mining. In order to increase the mining rate of coal resources and reduce the occurrence of accidents such as rock bursts, the technology of gob-side entry formed by roof cutting and pressure release (GEFRCPR) was investigated in fault-affected areas. The mechanism of gob-side entry formation passing through a normal fault was studied by theoretical analysis and numerical simulation, and control technology for entry formation was proposed. The results indicate that during the process of passing through a normal fault from hanging wall to foot wall, the vertical stress of the solid coal bank at the working face increased first, then decreased, rose and eventually reached a stable state. For the fault affected area, a combined support of " door type supports + cutting guard stents " was proposed as a temporary support for the formed entry and was tested on site. On-site monitoring showed that the degree of final deformation of surrounding rock of the formed entry was like: at the fault > before the fault > after the fault. By applying the proposed support technology, the deformation of the surrounding rock in the fault-affected area was effectively controlled so that the formed roadway appeared thereafter can be reused.