上覆煤柱影响区应力状态及冲击地压防治

Stress State of Overlying Coal Pillar Affected Zone and Its Prevention and Control of Rock Burst

上覆近距离煤柱会造成下层煤的应力集中及冲击危险。采用三维数值模拟,分析了不同宽度煤柱下底板应力分布与底板岩层破坏特征。研究表明:当煤柱宽度≤50 m时,煤柱底板应力呈"倒钟"形分布形态;当煤柱宽度>50 m时,煤柱底板应力呈"倒铁塔"式分布形态。煤柱中心最大应力集中系数与煤柱宽度呈幂函数关系,且随着煤柱宽度的增加,煤柱集中应力在底板中的衰减速度逐渐降低。上覆煤柱中心下方3煤层面的最大应力集中系数与煤柱宽度呈负指数关系。煤柱底板破坏范围与煤柱宽度呈负相关关系,煤柱底板岩层的破坏以剪切破坏为主。根据上覆煤柱影响划分了六采区3煤工作面冲击危险区,并提出了相应的防治技术。

Coal pillars in overlying coal seam with close distance can lead to the stress concentration and rock burst of lower coal seam. In order to figure out the stress distribution of floor and the damage characteristics of floor rock stratum, a three - dimensional numerical simulation method was applied in the study process. The study shows that the shape reflected in the simulation of coal pillar floor stress is like ＂inverted bell＂ when the width of coal pillar is less than or equal to 50 m; in other conditions, the shape is like ＂inverted tower＂. A power function relationship between maximum concentration stress of coal pillar center and coal pillar width, and with the increase of the width of coal pillar, the attenuation of coal pillars in the floor of stress concentration decreases gradually. The relationship of the maximum stress concentration factor of 3^# coal seam under overlying coal pillar center and the width of coal pillar is a negative ex- ponent function. The relationship of coal pillar failure range and the width of coal pillar is a negative exponent function; most of the damage in coal pillar rock stratum is shear failure. Based on the influence of overlying coal pillar, rock burst zones of the sixth mine section 3^# coal seam working face were divided, and corresponding prevention and control techniques were proposed.