采场底板裂隙扩展的分区特征及其临界应力条件  

Zoning characteristics and critical stress conditions of crack propagation in the longwall panel floor

作　　者：弓海军 刘一洪 赵洪宝[1] 李岳 荆士杰 GONG Haijun;LIU Yihong;ZHAO Hongbao;LI Yue;JING Shijie(School of Energy and Mining Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;Institute of Disaster Rock Mechanics,Liaoning University,Shenyang,Liaoning 110036,China)

机构地区：[1]中国矿业大学(北京)能源与矿业学院,北京100083 [2]辽宁大学灾害岩体力学研究所,辽宁沈阳110036

出　　处：《中国矿业大学学报》2024年第6期1132-1143,共12页Journal of China University of Mining & Technology

基　　金：国家自然科学基金面上项目(52374201);辽宁省属本科高校基本科研业务费专项资金项目(LJKLJ202416)。

摘　　要：为分析采场底板裂隙扩展机制,建立了采场底板裂隙扩展力学模型,推导了采场底板不同区域的裂隙扩展临界应力条件,通过数值模拟和现场监测对研究结果进行了验证.研究结果表明:采场底板破坏经历了剪切滑移、Ⅰ/Ⅱ型裂隙扩展、弯折裂隙扩展、宏观剪切破坏和卸荷张拉破坏5个过程.底板裂隙发生纯Ⅰ型断裂和纯Ⅱ型断裂时,临界应力随应力比和裂隙面摩擦系数的增加而增加,并且底板发生纯Ⅱ型断裂时的临界应力始终小于纯Ⅰ型断裂;底板裂隙发生弯折扩展时的临界应力随应力比的增加而减小,发生剪切破坏时,临界应力随应力比的增加而增加;底板发生卸荷张拉破坏时的临界应力主要与卸荷量和缺陷处的应力集中系数有关,缺陷处的应力集中系数主要影响临界卸荷量大小,卸荷量越大临界应力越小.In order to analyze the mechanism of crack propagation in the longwall panel floor,the mechanical model of crack propagation in the longwall panel floor was established,and the critical stress conditions for fracture propagation in different areas of the longwall panel floor were derived,and the research results were verified by numerical simulation and field monitoring.The results show that the floor failure has undergone five processes:shear slip,Ⅰ/Ⅱ fracture propagation,flexural fracture propagation,macroscopic shear failure and unloading tensile failure.When pure type Ⅰ fracture and pure type Ⅱ fracture occur in the floor,the critical stress increases with the increase of the stress ratio and the friction coefficient of the fracture surface,and the critical stress in the floor when the pure type Ⅱ fracture occurs is always less than that of the pure type Ⅰ fracture;The critical stress decreases with the increase of the stress ratio when the bending crack propagation occurs in the floor,and increases with the increase of the stress ratio when shear failure occurs;When the unloading tensile failure occurs in the floor,the critical stress is mainly related to the unloading amount and the stress concentration coefficient at the defect,and the stress concentration coefficient at the defect mainly affects the critical unloading amount,and the larger the unloading amount,the smaller the critical stress.

关 键 词：采场底板 裂隙扩展 临界应力 卸荷破坏 剪切破坏 

分 类 号：TD821[矿业工程—煤矿开采]