顶板-煤柱系统长期承载力学特征及破坏失稳机理

Various mine disasters are induced by the instability and failure of roof-coal pillar composite system under under long-term bearing. In this research, long-term bearing mechanical characteristics and instability and failure mechanism of roof-coal pillar composite system are investigated from the interaction between roof and coal pillar. The follwing innovation works are carried out: (1) Long-term bearing failure and instability of roof-coal pillar composite system are simulated through the long-term bearing tests on large-scale rock-coal composite bodies, and long-term bearing mechanical characteristics of composite bodies under different conditions are studied. Their failure and instability mechanisms are quantificationally analyzed from views of deformation localization and energy evolution. (2) Based on the above test results, the bearing capacity model for rock-coal composite body is established and its stress distribution characteristics are anlyzed, and mechanical characteristics and mechanism of interactions between rock and coal are revealed. A failure criterion of roof-coal pillar system considering interface effect is proposed, and combining failure characteristics of composite bodies and numerical calculation results, the failure and instability mechanism of roof-coal pillar system is analyzed. (3) Based on field measurement and numerical calculation, evolution laws of stress and deformation of coal pillar and roof and response mechanism between them are investigated during thepartition failure process of coal pillar, and an evaluation index system for failure and instability of roof-coal pillar system based on variety characteristics of deformation and stress of coal pillar and roof. The research results have important theoretical significance and engineering value for improving the mechanism of long-term bearing failure and instability of roof-coal pillar composite system and monitoring, preventing and controling its catastrophe.

顶板-煤柱系统长期承载破坏失稳诱发多种矿山灾害。课题从顶板与煤柱相互作用出发，围绕顶板-煤柱系统长期承载力学特征及破坏失稳机理，开展如下创新工作：（1）通过大尺寸岩-煤组合体长期承载试验模拟顶板-煤柱系统长期承载破坏失稳，阐释不同影响因素下组合体长期承载力学特性，从变形局部化、能量演化角度定量揭示其破坏失稳机理。（2）基于力学试验结果，建立岩-煤组合体承载力学模型，分析应力分布特征，明确岩-煤相互作用力学特征和机理；提出考虑界面效应的顶板-煤柱系统承载破坏准则，结合组合体破坏特征和数值计算结果，揭示顶板-煤柱系统破坏失稳力学机制。（3）基于现场实测与数值计算，获得煤柱分区破坏过程中煤柱和顶板应力、变形演化规律及其响应机制，建立基于煤柱和顶板变形、应力变化特征的顶板-煤柱系统破坏失稳评价指标体系。研究成果对完善顶板-煤柱系统长期承载破坏失稳机理及其灾变监测与防控等具有重要理论意义和工程价值。

为保障煤炭资源的安全、高效开采，采场周围留设了大量煤柱，这些煤柱及其上覆岩层组合系统的稳定性决定了整个采场及覆岩乃至地表的安全，一旦顶板-煤柱系统发生整体性破坏失稳，将导致许多灾难性后果。本项目采用理论分析、力学试验、相似模拟、数值模拟等相结合方法，研究了顶板-煤柱系统长期承载力学特征及破坏失稳机理：首先开展了不同岩煤高比、不同界面倾角、不同岩石特性下岩-煤组合体试样长期承载试验（模拟了顶板-煤柱系统长期承载破坏失稳），定义了组合体试样长期承载宏观破坏起裂，揭示了不同影响因素下组合体试样强度、变形、声发射、宏观破坏起裂特征，从变形局部化、能量演化角度定量揭示其破坏失稳机理；建立了岩-煤组合体协同承载力学模型，推导确定了应力分布函数和强度条件，提出了考虑界面效应的顶板-煤柱系统承载破坏准则；开展了顶板-煤柱长期稳定数值模拟与相似材料试验，研究了煤柱分区破坏过程中煤柱和顶板应力、变形演化规律及其响应机制；建立了顶板-煤柱协同承载弹性地基梁力学模型，提出了基于煤柱塑性区演化、顶板变形破坏演化的顶板-煤柱长期稳定与联动失稳动态判识方法，确定了临界失稳判据。. 在本项目执行过程中，首位或通讯作者在Journal of Cleaner Production、International Journal of Rock Mechanics and Mining Sciences、采矿与安全工程学报等国内外行业期刊上发表学术论文21篇，其中SCI、EI收录19篇；授权专利12项，其中国外发明专利1项、国内发明专利9项；获河南省科技进步三等奖（首位，公示结束）、中国煤炭工业协会科学技术二等奖（首位）、中国岩石力学与工程学会科技进步二等奖（首位）、山东省科技进步一等奖（第六位）、中国煤炭工业协会科学技术一等奖（第四位）等科技奖励6项；获山东省青年科技奖、全国煤炭青年科技奖、山东省优秀博士论文等荣誉。. 本课题研究将对完善顶板-煤柱系统长期承载破坏失稳机理及其灾变监测与防控、实现煤柱资源安全回收以及煤柱上方地表工程建设利用等具有重要的理论意义和工程价值。