迎上下采空孤岛面沿空掘巷围岩变形破坏特征

为了研究分析上下煤层两侧都采空而形成的孤岛面沿空掘巷和煤层开采时围岩应力分布及变形破坏特征,应用理论分析、计算机数值模拟与具体工程实践相结合的研究方法,分析了上下煤层两侧采空情况下,下孤岛工作面迎上孤岛面沿空掘巷期间及煤层开采过程中,采场围岩应力分布、变形破坏规律。结果表明:该情况下孤岛工作面围岩结构特征因受多次开采影响,其整体性和联动性都有所降低,采场围岩应力分布特征有所不同,且煤柱宽度尺寸对巷道受力变形有较大影响。掘巷期间轨道巷煤柱帮的变形量大于实体煤帮变形量,顶板下沉量大于底鼓量;回采期间顶板运移特点决定了两巷围岩主要呈现拉剪破坏,随着工作面的推进,采动影响阶段和影响剧烈阶段范围逐渐增大,巷道断面收缩率随着距工作面距离的减小而增大。对于孤岛面开采沿空巷道的特殊围岩条件,应遵循“强顶、固帮、控底的全断面围岩控制技术思路,对上下隅角附近巷道加强支护,提高围岩自身强度,为类似条件孤岛面巷道维护及安全开采提供理论技术保障。

Deformation and Failure Characteristics of Surrounding Rock in Gob-Side Entry during Mining between the Upper and Lower Gob Island

In order to study the stress, deformation and failure characteristics of surrounding rock in the upper and lower coal seam roadway driving along the gob island, it applied the theoretical analysis, computer numerical simulation and the specific engineering practice to analyze the roadway roof movement features and the regularity of stress distribution and deformation of surrounding rock damage during the roadway driving the up and down working face mining along gob island. Results show that: Because of the many times effects of mining, the whole structure of rock and correlation are all reduced, the stress distribution characteristics are different from those under the normal condition. The width of coal pillar has a great influence on the roadway deformation characteristics, the coal pillar side deformation quantity is larger than that at the entity coal side and the roof subsidence deformation is lager than the floor deformation during driving the gob-side roadway; During the working face mining, the roadway surrounding rock has mainly shear failure, and with the working face advancing, the scope of dynamic pressure and intense influence phase are increasing gradually, the reduction of area is increasing gradually. For the gob-side entry driving along the island mining, it should follow the whole section surrounding rock control technical approaches as “to strengthen roof, fix side and control floor”, strengthen the supporting of roadway near the upper and lower corners, and improve the surrounding rock strength, to ensure the island working face safety in production.