大倾角伪俯斜采场支架与围岩四维作用机理及稳定性研究

Steeply dipping seams are widely and complex distributed with high-quality in mine areas of China. In mining the steeply dipping coal seam, has many unsolved problems including the unbalanced load to support, rib fall, and flying gangue damage. The pitching oblique mining is an effective way to solve the problems, but the research on relationship and stability of support- rock system in pitching oblique longwall mining area still belongs to blank space. The revelation of spatio-temporal mechanism of support-surrounding rock and interaction response mechanism of instability to stability of support-rock system is the scientific basis to realize the safe and efficient oblique mining of steeply dipping seam, which has important theoretical and practical significance. Based on the integrated research methods including 3D multiple scale physical simulation, numerical simulation modeling and in-situ testing, the spatio-temporal conversion and scale effect of stress and movement of surrounding rock has been considered. The four-dimensional characteristics of the load transfer between rock and support was revealed. The mechanical model of “coal wall-roof and support-gangue” system along strike and “roof-support and support-floor” system at inclined direction were eastablied, and the contribution degree of different surrounding rock composition to the system stability and interaction characteristics between the systems were determined. The damage mechanism of “support-rock” system failure was expounded and the control methods of system stability were proposed, which are theoretical foundations for strata control and supports anti-skid in fully-mechanized oblique longwall mining area of steeply dipping seam.

我国大倾角煤层埋藏复杂、赋存广、资源优质，大倾角煤层走向长壁开采中支架受载不均衡、煤壁片帮与飞矸频发等问题一直未能解决，采用伪俯斜综采是有效途径，但大倾角长壁伪俯斜采场支架与围岩关系及稳定性研究尚属空白，揭示其采场支架与围岩时空作用机理、“支架-围岩”系统失稳-稳定交互响应机制，是实现大倾角伪俯斜安全高效开采的科学基础，具有重要的理论与实践意义。课题采用三维多尺度物理模拟、多元数值仿真与现场实测互馈方法，研究大倾角长壁伪俯斜采场围岩应力与运移的时空转换与尺度效应，揭示支架与围岩间载荷传递四维特征及其施载与受载机理，建立采场走向“煤壁-顶板与支架-矸石”与倾向“顶板-支架与支架-底板”系统力学模型，确定不同围岩组合对系统稳定性的贡献度及系统间的相互作用规律，阐明“支架-围岩”系统失稳致灾机制，提出系统稳定性控制方法，为解决大倾角煤层长壁伪俯斜综采岩层控制、支架防倒滑等技术难题提供科学指导。

大倾角煤层长壁工作面支架受载不均衡、煤壁片帮与飞矸等问题频发，伪俯斜综采是有效解决手段，但实现“支架-围岩”稳定控制是大倾角伪俯斜安全高效开采的关键，因此，亟需开展大倾角长壁伪俯斜采场“支架-围岩”时空作用机理及稳定性研究。.采用物理模拟与数值实验、理论分析与现场实测互馈方法，研究了大倾角长壁伪俯斜采场围岩时空应力演化和顶板破断与垮落充填规律、“支架-围岩”相互作用机理及致灾机制。结果表明，大倾角长壁伪俯斜采场围岩应力分布、位移演化和破断特征均呈非对称性，其应力、位移三维空间逐渐演化成“上宽下窄”形态，基本顶呈俯斜状“O-X”破断，均具有明显时序性，与一般大倾角工作面明显不同。中厚煤层伪俯斜采场的倾斜中部有大量垮落顶板堆积充填现象，中上部垮落顶板堆积程度大于倾斜下部区域，并给出不同开采阶段时的基本顶挠度、内力方程及破断判据。得到大倾角硬矸-软煤夹层顶板下，支架最大阻力与软煤夹层厚度呈正比关系，支架达最大阻力后，则其随软煤夹层继续厚度增而降低。.大倾角伪俯斜工作面较真斜工作面，支架间相互作用更明显，工作面来压期间倾斜上部区域支架各构件受载明显增加，呈现上部区域＞中部区域＞下部区域。沿伪俯斜工作面自下而上支架的偏载程度和空载率逐渐增大，其走向“支架-围岩”系统的稳定性则逐渐减弱，工作面倾斜中上部区域顶板运移程度较大，支架易受冲击载荷作用。顶板切向载荷及其作用位置对支架稳定性影响显著，确保工作面倾斜中上部区域顶板稳定并及时调整支架位态可有效控制支架稳定。当工作面顶底板较稳定时，支架保持稳定时的临界工作阻力远小于其正常工作阻力；当顶板不稳定时，支架受载不均衡且易发生失稳，支架的运动幅度和失稳概率与工作阻力成反比。当工作面中上部区域基本顶破断或切落时，会加剧支架的偏转失稳。提出了多维度”“支架-围岩”系统稳定性控制方法。以上为解决大倾角伪俯斜采场多尺度岩层与装备协同控制提供了重要的科学依据。