Study on the Mining Pressure Law of Tunneling Roadway in Coal Pillar of Lower Coal Seam in the Mining Hollow Area

ABSTRACT In the downward mining, the goaf of the upper coal seam and the remaining coal pillars will have a negative impact on the stability of the lower coal seam roadway. If the roadway is excavated in the lower coal seam coal pillar, it is more likely to produce mutual superposition effects, which greatly increases the difficulty of roadway surrounding rock control. In view of this situation, based on the actual project on site, the engineering geological survey, theoretical analysis, numerical simulation, field measurement and verification are used to study the stress distribution characteristics of the goaf and the remaining coal pillars in the upper coal seam and the mine pressure law of the surrounding rock of the roadway when the lower coal seam is arranged in multiple roadways, and the safety of the new roadway is verified by field measurement. The results show that from the perspective of the damage degree and stress concentration of the upper coal seam floor, the goaf of the upper coal seam and the remaining coal pillars have no obvious influence on the new roadway in the lower coal seam coal pillar, and the new roadway has no obvious influence on the two existing roadways in the same coal seam. The roof and floor convergence of the newly excavated roadway is about 70 mm, and the two sides are about 106 mm. The deformation does not affect the use of the roadway.