顶底板岩性对条带煤柱应力及塑性区影响研究

Study on the Effects of Rock Property of Roof and Floor on the Stress and Plastic Zone of Strip Coal Pillar

运用FLAC^(3D)数值模拟软件模拟了不同岩性顶、底板条件下条带煤柱变形破坏过程,研究分析了不同岩性顶、底板对条带煤柱应力演化特征及塑性区分布规律的影响。结果表明:顶、底板岩层的强度越大,条带煤柱承受的应力越大,应力集中程度越大;而顶、底板岩层的强度越小,条带煤柱的应力集中程度越小,而其塑性区扩展越大,且上部破坏越严重;泥岩作为顶板时,上部较下部破坏大,形成上大而下小的塑性区;中砂岩、细砂岩作为顶板,泥岩作为底板时,下部较上部破坏大,形成上小而下大的塑性区;中砂岩及细砂岩作为顶、底板时,中部较上、下部破坏严重,形成中部大而上、下部小的塑性区。研究结果对不同岩性顶、底板条件下条带煤柱留设具有一定的工程实践意义。

The deformation failure process of strip coal pillar under different rock properties of roof and floor was simulated by FLAC3D software. And the effects of different rock properties of roof and floor on the stress evolution of strip coal pillar were analyzed, as well as the effects on the distribution law of plastic zone. The results showed that the larger the strength of rock stratum in roof and floor, the larger the stress and the stress concentration of strip coal pillar. While the lower the strength of rock stratum in roof and floor, the smaller the stress concentration of strip coal pillar, the greater the extension of plastic zone and the more serious the failure in upper part of strip coal pillar. When the roof was mudstone, the failure in upper part of strip coal pillar was more serious than that in the lower part, forming the plastic zone that was large in upper part and was small in lower part. However, the failure characteristic and the plastic zone of strip coal pillar were opposite when the roof was medium sandstone and packsand, and the floor was mudstone. When the roof was medium sandstone and the floor was packsand, the failure in middle part of strip coal pillar was more serious than that in upper and lower part, forming the plastic zone that was large in middle part and was small in upper and lower part. The research results had a certain practical significance for setting the strip coal pillars under the different rock properties of roof and floor.