动压巷道顶板非均匀剧烈变形机理及其稳定性控制

来源期刊:中南大学学报(自然科学版)2020年第5期

论文作者:李臣 霍天宏 吴峥 吕坤 张兵

文章页码:1317 - 1328

关键词:顶板下沉;蝶形塑性区;应力分布;支护阻力;稳定性控制

Key words:roof sag; butterfly plastic zone; stress distribution; support resistance; stability control

摘    要:针对布尔台矿保留巷道受一次采动影响后出现的顶板非均匀剧烈下沉且补强微效的情况,综合现场监测、理论分析、数值计算等方法,分析采空区侧方应力分布规律及其影响下的巷道塑性区发育特征,并对支护阻力对采掘应力场和采动塑性区的控制作用进行系统研究。研究结果表明:1) 巷道围岩围压比控制围岩塑性区的发育形态,不同强度的围岩对蝶形塑性区的成蝶敏感性不同,且蝶形塑性区具有方向性;2) 受采动影响,采空区侧方最大最小主应力的变化引起主应力方向与围压比处于动态变化中;3) 受应力变化的影响,侧方不同位置塑性区也是变化的,且不同围岩成蝶敏感性的不同导致顶板出现隔层塑性破坏,非均匀塑性区内岩石破坏对应的膨胀压力及碎涨变形导致巷道非均匀剧烈下沉及锚索破断;4) 巷道工程现有支护水平对采动塑性区的控制作用有限,解释了给定条件下大密度补强的作用有限性。

Abstract: Aiming at the situation that the roof of the reserved roadway in Buertai mine was not uniformly and violently subsiding and the reinforcing effect was small after mining in the adjacent working face, field investigation, theoretical analysis and numerical calculation were used to analyze the distribution law of lateral stress in goaf and the development characteristics of roadway plastic zone, and the control effect of support resistance on mining stress field and mining plastic zone was studied systematically. The results show as follows. 1) The shape of the plastic zone of roadway surrounding rock is controlled by the confining pressure ratio. The surrounding rock with different strengths has different butterfly sensitivity to the plastic zone, and the butterfly plastic zone is directional. 2) Under the influence of mining, the variation trend of the maximum and minimum principal stress on the side of goaf leads to the dynamic change of the principal stress direction and confining pressure ratio. 3) Plastic zones at different locations on the side is varyied, and different rocks have different butterfly sensitivity, which results in plastic failure of the top layer. The rock failure in the non-uniform plastic zone causes the roof of the roadway to sink violently and the anchor cable to break. 4) The existing support level has limited control on the mining plastic zone, which explains the small effect of large density reinforcement.

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