大采高沿空留巷围岩稳定性及形变规律分析

为了研究云驾岭矿深部大采高沿空留巷围岩稳定性及形变规律,采用理论分析、现场实测和实验室测试综合研究手段和方法,确定了试验工作面巷旁充填体支护阻力和留巷参数,构建了能够反映沿空巷道受初次采动围岩形变规律的回归函数模型,对比分析了一次和二次开采扰动下围岩的应力应变状态,探究了充填体上方顶板岩层的应力传递规律。结果表明,采用弹塑性力学模型得出的巷旁充填体的临界支护阻力和充填体宽度分别为4.1MN/m和2.47 m,经实验室测试和工业性试验,能够保持高水材料充填体的稳定。受初次采动影响,沿空巷道围岩位移量与工作面至测站点距离之间符合Slogistic增长函数模型,求解了巷道顶板、底板和下帮的最大变形量、变形量最大时工作面的位置以及达到最大变形时工作面推过观测站的时间。对于沿空巷道,工作面超前支承压力波及范围至工作面煤壁前方约34 m,留巷顶板3.8 m以浅的采动裂隙可能会导致顶锚杆锚固失稳甚至失效,充填体切顶阻力的“波动性”能够反映顶板岩层的分层垮落特征。

Surrounding Rock Stabilization and Deformation Evolution of Gob-side Entry Retaining in Deep Colliery with Mega-height Coal Seam Extracted

With the intention of studying surrounding rock stabilization and deformation evolution of gob-side entry retaining with mega-height mineral deposit seam extracted in Yunjialing deep coal pit, China, comprehensive research methodologies like theoretical analysis, onsite investigation and engineering workshop test were conducted. The supporting resistance of backfilling body with high-water quick-setting materials and parameters of gob-side entry retaining in tested working face were determined. Moreover, regressive functional models which could represent deformation evolution of surrounding were built under the first influence of coal mining. The stress-strain status of gob-side entry induced by first and repetitive coal extraction also were compared and analyzed. Furthermore, stress transmission evolution of roof strata over backfilling body was discussed based on tested coal panel. It indicates that for roadway-side backfilling body, critical supporting resistance and backfilling body width derived from plastoelastic mechanical model are 4.1MN/m and 2.47m respectively, which can retain the stabilization of backfilling body of high-water quick-setting materials after testing in engineering workshop and investigating onsite. The interrelation between surrounding rock displacement of gob-side entry retaining and the distance from working face to monitoring station is rationally in alignment with Slogistic growth functional model due to the first influence of panel extraction. Thereafter maximum deformation magnitudes of roof and floor strata together with dip-side coal wall of gob-side entry are solved. The working face site, where maximum deformation appears, and the time of the working face passing the observation station, when the maximum deformation is reached, are also solved. For gob-side entry retaining, the wave range of the advance abutment pressure of the working face is about 34m in front of the coal wall of the working face. Mining-induced fracture over gob-side entry roof strata within 3.8m can prompt roof anchor bolts to be instable, even invalid. The fluctuant property of roof-cut resistance of backfilling body characterizes stratiform caving of roof strata.