【作者】 肖亚勋；

【导师】 谭云亮； 赵同彬；

【作者基本信息】 山东科技大学 ， 固体力学， 2009， 硕士

【摘要】 本文以北京木城涧煤矿+570水平六石门区域的三槽上行开采为工程背景,采用理论分析、数值模拟和现场探测相结合的综合研究方法,对煤层间距平均仅33.5m的近距离底部临空条件下底板破裂及其稳定性进行了研究。结合岩体卸荷应力应变曲线,分析了底部临空开采节理岩体采动损伤机理;利用卸荷模量的衰减定义了损伤变量,在进行了一些假定的情况下推导了节理岩体采动损伤本构模型,对该模型的特性分析表明:其能够很好的反映出由开采引起的节理岩体卸荷效应。对底部临空开采进行了UDEC数值模拟,模拟结果表明:二、三槽开采的过程中,对三槽底板应力分布造成的影响为拱形;当考虑岩体卸荷损伤特性时,三槽底板的各岩层所受影响均较大,三槽直接底及底板中间区域靠近二槽基本顶处还出现了较明显的离层。通过现场底板钻探、钻孔摄像探测及底板离层监测等综合手段,对三槽底板稳定性进行了探测研究。结果表明:三槽底板向下破碎带分布的趋势依次为弱裂隙带、微裂隙带及强裂隙带;其中微裂隙带是一关键层,其能保证三槽底板在开采过程中处于稳定状态。对现场探测和数值模拟结果进行了对比,结果表明:考虑岩体卸荷损伤特性能更好的体现出工程实践中三槽底板的破碎带分布规律、离层显现特征及三槽开采过程中直接顶的垮落规律。因此,在开采过程中考虑岩体的卸荷损伤特性十分必要。更多还原

【Abstract】 Based on the anti-procedure mining of No.3 seam for No.6 crossheading at +570m level in Muchengjian mine in Beijin, the fracture and stability of floor under short distance with the average layer space of 33.5m and mined bottom is researched by theory analysis, numerical simulation and field detection.The unloading damage mechanism of jointed rock for mining under mined bottom is analyzed according to the stress-strain curve of unloading rock. The damage variable is defined by the attenuation of unloading module and the mining damage constitutive model of jointed rock is deduced under several hypothetical situations. The feature analysis of this model indicates that it can reflect the unloading effect of jointed rock caused by mining well.The mining under mined bottom is simulated by DEM software UDEC. The simulation results indicate that the acted effect for the stress distribution of strata in the No.3 seam’s floor is arched in the process of mining No.2 and No.3 seam. The acted effect of No.3 seam’s floor with considering unloading damage is bigger and the separations appear in the direct floor and close to the main roof of No.2 seam in the middle of the floor obviously.The stability of floor in the No.3 seam is detected in field by floor drilling, borehole camera detection and floor separation monitoring. The results of field detection indicate that the distribution trend of frcture for the No.3 seam’s floor is weak, tiny and strong fracture zone from top to bottom and the tiny fracture zone is the key layer which ensures the stability of No.3 seam’s floor in the process of mining.The comparision between field detection and numerical simulation indicates that it can reflect the real distribution law of fracture zone for the No.3 seam’s floor, the behavior feature of separation and the caving law of direct roof in the process of mining No.3 seam well with considering unloading damage. Therefore, it is quite necessary to consider the unloading damage in the process of mining.更多还原