关键词: 不规则煤柱, 冲击地压, 采动应力, 煤柱失稳, 数值模拟

Abstract: In order to study the characteristics of the stress field of the irregular coal pillar left over from the upper coal and the impact on the impact risk when mining the lower coal face, and put forward targeted rock burst prevention measures, according to the methods of numerical simulation, source analysis of microseismic events and engineering analogy, when mining the 18305 working face of Jining No. 3 coal mine, outside the influence area of the upper irregular coal pillar Numerical simulation and stress analysis are carried out for different stress characteristics near the affected area and entering the coal pillar area, the influencing factors of rockburst are fully studied, and the coal rock strength weakening and anti scour treatment measures for lower coal mining in the coal pillar affected area are formulated. The research shows that the vertical stress of the coal body in the left pillar area of the upper coal mostly presents an asymmetric "saddle" distribution, forming an obvious stress concentration. With the push mining of the working face, the coal pillar area is shrinking, the peak value of vertical stress in the coal pillar area continues to rise, microseismic events are concentrated in the coal pillar area, and high-energy events occur frequently, indicating that the coal and rock mass in the coal pillar area overlaps the influence of mining stress under its own high stress state, resulting in large-scale fracture and increased impact risk. The microseismic trend analysis shows that when the working face advances to 50m near the coal pillar area, the vertical stress of the coal pillar superimposes the advance mining stress of the working face to reach the stress peak. The anti scour scheme of deep hole blasting in hard roof strata and pressure relief by large-diameter drilling of coal body during lower coal mining in the coal pillar affected area is formulated. The field practice shows that the measures of deep hole blasting in roof strata with large charge and pressure relief drilling of coal body can significantly reduce the stress level of coal and rock mass in the area affected by irregular coal pillar, It can effectively avoid the occurrence of rockburst in the area affected by deep irregular coal pillar.