矿井残存煤柱-岩层联动失稳理论基础研究

Residual pillar collapsing induces strata fracturing and rapidly falling, is becoming a regular threat in some old mines in China, so it is no time to delay to solve key problems of strata failure expending and collapsing aroused by residual pillar breaking out in multi-mining. In this project, theoretical analyses, laboratory experiments, numerical simulations and in-situ explorations will be combined to carry out following innovative researches：(1) Learn overburden strata failure distribution and expansions due to multi-mining in coal seam group exploration, investigate the developing process and dynamical behaviors from pillar and roof fracture to their linkage collapsing. By combining elasto-plastic structural mechanics and catastrophe theory, we expect to put forward a new theoretical hypothesis named after Linkage Movement of Pillar and Roof. (2) Investigate gradient distribution of pillar fracturing and stress from the exterior to the interior, obtain a pillar bearing capacity vs time, by utilizing fractal and rheological theories, and put up a long term forecasting and predicating approach for pillar collapses. (3) Learn pillar-strata linage failure development, and make a mechanical solution for the impact dynamic energy aroused by linkage strata collapsing, in order to obtain a calculation mode of dynamic energy, which will supply a foundation for establish a safe and reliable roof support design approach. This project aims to establish a theory on strata control of multi-coal seam extraction, and to make a substantial contribution reach early the goal of scientific and accurate control on strata.

我国许多矿井因残留煤柱失稳导致岩层突发塌垮，给生产安全造成严重威胁，深入解答煤柱-岩层破断联动失稳方面的关键科学问题已刻不容缓。本项目拟采用理论分析、试验研究、数值模拟和工程测试相结合的手段，拟开展如下创新研究：(1)从揭示多煤层开采覆岩破裂分布及扩展增量规律出发，研究煤柱-岩层破断演化结构特征、联动机制，并基于弹-塑性结构动力学与突变理论，提出“煤柱-岩层破断结构联动灾变”假说；(2)研究煤柱破坏程度和应力分布梯度变化规律，采用分形与流变损伤力学表征方法，获得煤柱承载能力-时间变化式，依据极限失稳条件提出煤柱长时失稳预测预报方法；(3)基于煤柱-岩层破断联动失稳力学演化过程，对破断联动失稳塌垮岩层所产生冲击动能进行力学解算，获得冲击动能计算式，构建安全可靠顶板支护设计方法。本项目将构建多煤层开采条件下煤柱-岩层联动灾害防控理论，为最终实现岩层精准控制的目标作出实质性贡献。

采用室内试验、理论分析、数值模拟和现场探测等手段，对煤柱-岩层联动失稳致灾特征、联动失稳机理开展了深入研究，取得成果如下：.（1）采用自主研发的BGYD-600型变刚度煤岩动力破坏试验系统，研究获得了不同刚度顶板条件下煤样力学特征和能量积聚与释放规律，建立了基于刚度影响的煤样失稳力学机制。.（2）通过室内相似材料模拟试验和数值模拟试验，获得了多煤层开采时煤柱、岩层的破坏以及破断垮落特征；揭示了遗留煤柱宽度、顶底板岩性以及层间距等对多煤层开采煤柱-岩层联动失稳影响规律。.（3）在分析煤柱主要破坏形式和破坏特征的基础上，通过对煤柱安全稳定性及煤柱集中应力传递分析，探讨了由煤柱失稳诱发岩层联动失稳力学过程，获得了煤柱渐进破坏和煤柱冲击破坏时机理；基于尖点突变理论，考虑煤柱片帮、流变以及塑性区耗散能影响，得到了煤柱-岩层联动失稳时的刚度判据。.（4）充分考虑岩层力学性质、开采深度、开采厚度、开采范围、上下采动影响等因素，揭示上方坚硬岩层破裂结构影响范围、应力传递规律，得到支护强度计算方法，并对大同同忻矿开采侏罗系15#煤层工作面遗留煤柱区支护强度进行估算。. 项目共发表论文31篇（其中SCI 论文25篇、EI论文6篇，国际顶级期刊13篇），出版著作1部；授权国内外发明专利19项；获得省部级奖励6项；培养博士生4名（已毕业）、硕士生12名（已毕业7名，在读5名）、博士后5名；国内国际学术报告17次。