煤矿地下水库是解决西部矿区水资源保护利用的关键技术之一，维持水库安全运行的基础是工程安全，而水库坝体是保证工程安全的核心。针对煤矿地下水库煤柱坝体安全稳定问题，从煤柱坝体受到的顶板岩层压力（垂向应力）、储水高度（水平应力）角度出发，基于力学模型、相似模拟和数值计算等方法，综合分析煤柱坝体破坏时应力变化（垂直应力和水平应力）、裂隙发育及扩展情况、位移变化等多参量变化规律，研究煤柱坝体破坏时各参数变化特征，提出煤柱坝体破坏前兆关键信息，为现场煤矿地下水库安全运行监测预警提供基础。研究结果表明：煤柱坝体在垂直应力作用下，上覆岩层应力造成煤柱坝体破坏的位置首先为煤矿地下水库侧的坝体顶板处，煤柱尺寸越小越容易产生应力集中，承载的应力越大发生破坏的可能性越大，基于此得到了煤柱坝体破坏临界点；水平应力作用下，煤柱坝体共经历弹性阶段、初始破坏阶段和破坏增加等3个阶段，煤柱坝体在达到极限强度后才显现较明显的位移，煤柱坝体受到损伤，在水平应力降低后位移有回弹趋势，但煤柱坝体不适宜再继续储水；分析了引起煤柱坝体发生失稳的主要因素，垂直应力和水平应力共同作用下，煤柱坝体发生失稳的部位主要在临库侧小尺寸坝体顶板、底板及中间位置，以上湾矿为例，得到了15 m煤柱坝体能承载最大水头高度为50 m，但此时煤柱坝体已经发生破坏，即使降低水位煤柱坝体整体稳定性也受到不可恢复性破坏；综合研究煤矿地下水库煤柱坝体发生失稳的特点和规律，结合位移变化及煤柱坝体物理力学性质，得到了煤柱坝体破坏前兆信息，即在外力作用下达到极限强度前应对水库进行安全处理措施，建议在现场监测预警时重点监测水库侧尺寸较小的煤柱顶板应力变化信息，保障煤矿地下水库安全运行。

Coal mine underground reservoir is one of the key technologies to solve the protection and utilization of water resources in western mining areas. The basis for maintaining the safe operation of the reservoir is engineering safety, and the dam body is the core to ensure engineering safety. This paper studies the safety and stability of coal pillar dam of underground reservoir in coal mine. The stress variation (vertical stress and horizontal stress), fracture development and expansion, displacement variation and other multi-parameter variation laws during the failure of coal pillar dam are comprehensively analyzed based on mechanical model, similarity simulation and numerical calculation methods, from the angle of roof rock pressure (vertical stress) and water storage height (horizontal stress). This paper studies the variation characteristics of various parameters during the failure of coal pillar dam, and puts forward the key information of coal pillar dam failure precursors, which provides the basis for the safe operation monitoring and early warning of on-site coal mine underground reservoir. The results show that under the action of vertical stress, the location of coal pillar dam damage caused by overburden stress is the dam roof on the side of underground reservoir of coal mine. The smaller the size of coal pillar is, the easier it is to produce stress concentration. The greater the bearing stress is, the greater the possibility of damage is. Based on this, the failure critical point of coal pillar dam is obtained. Under the action of horizontal stress, the coal pillar dam body experiences three processes: elastic stage, initial failure stage and failure increase stage. The coal pillar dam body shows obvious displacement only after reaching the ultimate strength. At this time, the coal pillar dam body is damaged. After the horizontal stress decreases, the displacement has a rebound trend, but the overall stability of the coal pillar dam body is affected and it is not suitable to continue water storage. The analysis of the main factors causing the instability of the coal pillar dam shows that under the combined action of vertical stress and horizontal stress, the instability of the coal pillar dam is mainly at the top plate, bottom plate and middle position of the small-size dam near the reservoir. Taking Shangwan mine as an example, the maximum bearing head height of the coal pillar dam is 50m, but the coal pillar dam has been damaged at this time. Even if the water level is lowered, the overall stability of the coal pillar dam is irreparably damaged. Comprehensive study of the characteristics and laws of coal pillar dam instability in coal mine underground reservoirs, combined with displacement changes and the physical and mechanical properties of coal pillar dams, obtained the precursor information of coal pillar dam failure, that is, respond to the reservoir before reaching the ultimate strength under the action of external force. For safety measures, it is recommended to focus on monitoring the stress change information of the coal pillar roof with a smaller size on the reservoir side during on-site monitoring and early warning to ensure the safe operation of coal mine underground reservoirs. The research results provide a basis for monitoring and early warning methods for the safety and stability of coal pillar dams in coal mine underground reservoirs.