采空区冒落矸石堆积特性及长期承载变形机制

The area of gob is large in China, the caved gangue in gob is in the state of long-term pressure-bearing, the decrease of bearing capacity or excessive deformation may induce a variety of mine disasters. This project will be studied by rock particle-size distribution test, rock mechanics test, bearing deformation test of broken rock, numerical simulation, field test and theoretical analysis, as follows. ①The relationship between rock particle-size and mechanical properties, the relational model between lumpiness fractal dimension of broken rock and rock mechanical properties, the effect of rock particle-size distribution to lumpiness gradation of broken rock. ② The natural lumpiness gradation, hinged connection type and stress state of caved gangue, the relational model between broken expand property and hinged connection type. ③The deformation characteristics of broken rock with different lumpiness gradation under different loading methods, the change of lumpiness gradation of broken rock before and after bearing deformation test, slow and sudden deformation mechanism of broken rock under long-term load. The research will provide a new theoretical basis for prediction and prevention of lagging water-inrush of overlying strata affected by mining and surface subsidence above gob, and has important significance in disaster prevention caused by the decrease of bearing capacity or excessive deformation of caved gangue.

我国煤矿采空区面积巨大，采空区内冒落矸石处于一种长期承压状态，其承载能力降低或变形过大会诱发多种矿山灾害。本课题采用岩石粒度组成测试、岩石力学试验、破碎岩石承载变形试验、数值计算、现场测试与理论分析相结合的方法开展如下研究：①研究岩石的粒度组成与力学性能的相关性，构建破碎块度分形维数与力学性能的关系模型，探讨岩石粒度组成对破碎块度级配的影响；②研究冒落矸石的自然块度级配、铰接形式及受力状态，构建不同块体铰接模型，建立矸石碎胀系数与铰接形式间的关系模型；③研究不同块度级配的破碎岩石在不同加载方式下的变形特征，对比荷载作用前后破碎岩石块度级配变化，给出破碎岩石长期荷载下的徐变和突变机制。课题研究将为采动覆岩滞后突水及采空区地表塌陷预测与防治提供新的理论基础，对因冒落矸石承载能力降低或变形过大诱发的灾害防治具有重要意义。

我国煤矿采空区面积巨大，采空区内冒落矸石处于一种长期承压状态，时间效应对其影响极为显著，冒落矸石会因承载能力降低或变形过大而减弱对覆岩的支承作用，极易加剧采空区围岩结构失稳，引发矿井突水、地表塌陷和地表建（构）筑物的破坏。本课题在前期研究的基础上，采用岩石粒度组成测试、岩石力学试验、破碎岩石承载变形试验、现场测试与理论分析等方法，研究了岩石的粒度组成与力学性能的相关性；提出了沿空留巷条件下采空区冒落矸石堆积特性测定方法，获得了采空区内冒落矸石自然块度级配和铰接模式；提出了采空区冒落矸石受力特征实测方法，得到了采空区冒落矸石受力规律；自主研发了组合式破碎岩石承压变形实验装置，实现了破碎岩石承压变形过程中侧向压应力的精确测量；研究了不同块度级配的破碎岩石在不同加载方式下的变形特征，对比了荷载作用前后破碎岩石块度级配变化，给出了破碎岩石长期荷载下的徐变和突变力学机制。.相关研究成果在《Geofluids》和《Geomechanics and Engineering》等国内外期刊上发表论文5篇，其中，SCI论文2篇，EI论文3篇；出版《矿井采动覆岩涌水溃砂致灾机理及防治》学术专著1部；申请发明专利5项，授权发明专利3项；获得省部级科研奖励2项。课题研究将为采动覆岩滞后突水及采空区地表塌陷预测与防治提供新的理论基础，对因冒落矸石承载能力降低或变形过大诱发的灾害防治具有重要意义。