上分层遗留煤柱形成阶段和回收期间的应力演化规律

Stress Evolutionary Laws of Retained Coal Pillar at Upper Layer in Forming and Recovering Stage

为保障上分层遗留煤柱高效安全回收,通过数值模拟和现场实测相结合的方法分别研究了煤柱在形成阶段和回收期间的应力演化规律。结果表明:煤柱两侧工作面开采致使煤柱区应力叠加,下分层煤体沿工作面倾向呈现原始应力区、应力集中区和卸压区的交替形式;当煤柱形成有200 m和回收至200 m时,煤柱在形成阶段和回收期间的应力最大值接近,分别为35 MPa和35.05 MPa,但受支撑作用影响,两者最大应力值分别位于开采方向中部100 m和开采方向200 m;煤柱形成阶段的应力演化结果能够满足煤柱安全回收要求。

To ensure the efficient and safe recovering of retained coal pillar in upper layer,this paper studies the stress evolution laws of retained coal pillar during forming and recovering stage by numerical modeling and spot investigating. The results showed that the coal pillar appeared stress superposition because of working face mining in both sides of coal pillar,along the direction of working face tendency,the stress of coal rock under lower layer face appeared alternative form of original stress zone,stress-concentrated zone and distressed zone. The maximum stress is almost equal when the formation of coal pillar is 200 m and coal pillar recovers to 200 m,and the stress is 35 MPa and 35. 05 MPa respectively; the location of the maximum is located at 100 m and 200 m along the direction of mining because of the influence of supporting. The stress evolutionary laws in forming stage can meet the safe requirements of recovering coal pillar.