极弱胶结地层煤巷支护体系与监控分析

Research and monitoring analysis of coal roadway bolting system in very weakly cemented stratum

针对极弱胶结地层煤巷围岩自稳能力差、自稳时间短、围岩变形剧烈等特征,采用FLAC3D深入揭示了矩形、切圆拱形与直墙拱形等3种断面形状煤巷开挖后围岩位移、塑性区及应力分布规律,确定了极弱胶结地层煤巷合理断面形状;结合国内外煤巷支护理论与技术,提出了极弱胶结地层煤巷"双层锚固平衡拱结构",基于煤层厚度与巷道埋深,分类提出了极弱胶结地层煤巷支护技术方案,模拟验证了支护方案的合理性与可行性;基于围岩变形与支护结构受力实时监测及分析,动态掌握了极弱胶结地层煤巷围岩变形与支护结构受力状态,评价了支护效果与验证了支护方案的可行性。监测结果表明,切圆拱形断面煤巷成型较好、受力均匀,有利于巷道围岩的整体稳定,提高了煤巷开挖后的自稳与承载能力;锚网索联合支护技术方案有效地控制了极弱胶结地层煤巷围岩大变形与破坏,保证了巷道围岩与支护结构的长期稳定及安全。

The displacements,plastic zone and stress distribution were revealed by FLAC3 D in three cross section shape of rectangle,tangential arch and straight wall arch after excavation according to the characteristics of very weakly cemented stratum with low self-stable ability,short stable time and deformation severely. The reasonable section shape of coal roadway was determined in very weakly cemented stratum.Combining with the roadway supporting theories and technologies at home and abroad,a ＂Double anchorage balance arch structure＂in very weakly cemented stratum was put forward.The different roadway supporting technology solutions was proposed based on the coal seam thickness and buried depth of roadway.The rationality of the supporting scheme has been validated by FLAC3 D.Based on the real-time monitoring and analysis,the surrounding rock deformation and supporting structure stress were dynamically known; the supporting effect and supporting schemes feasibility were valued. Monitoring results show that the circle arch roadway form is a good form,and its stress is uniform.It is in favor of the overall stability of the surrounding rock,and the stabilityand bearing capacity are raised.Combining supporting scheme with bolting wire mesh technology solutions can effectively control the large deformation and destruction of roadway surrounding rock in very weakly cemented stratum,and the longterm stability and safety of the roadway surrounding rock and supporting structure can be warranted.