矿井关闭或废弃前，采空区遗留支撑煤柱受周边工作面采动、覆岩载荷等影响，产生了一定的损伤破坏；矿井关闭或废弃后，采空区一旦形成承压积水环境，将加剧煤柱支承性能劣化，可引发其破坏失稳，造成地表突然塌陷等灾害。为研究初始损伤和压力水浸对关闭或废弃矿井遗留支撑煤柱的耦合劣化作用，基于自主研发的煤岩压力水浸试验装置，进行了5组不同初始损伤的压力水浸煤样单轴压缩试验，结合XTDIC三维全场应变测量系统、扫描电子显微镜等系统，分析了煤样强度、变形破坏与能量演化等特征，从宏细观结构演化、矿物组分变化等方面揭示了煤样力学特性劣化机制。研究结果表明：① 基于煤岩黏弹塑性变形理论，将循环加卸荷产生的耗散能细分为塑性损伤能与阻尼能，重新定义了煤岩循环加卸荷初始损伤量，计算获得5组煤样平均初始损伤量分别为0、0.071、0.114、0.205和0.309；② 压力水浸煤样单轴抗压强度、弹性模量与初始损伤量呈负相关，而峰前塑性变形与初始损伤量呈正相关；随着初始损伤量增大，煤样缺陷处应力集中现象愈发显著，形成多个变形局部化带，其位移错动量变化率波动剧烈，且煤样破坏模式由拉伸破坏向拉–剪混合破坏转变，破碎程度增大；③ 初始损伤和压力水浸耦合作用下，煤样内部孔隙、微裂纹等萌生发育，颗粒间黏结力降低，内部结构由致密向疏松多孔转变，同时煤样宏观裂纹发育扩展，削弱了煤样实体承载结构，这是导致其力学特性劣化的根本原因，对应着煤样储能能力降低，峰后破坏动力显现强度减小。

Before the closure or abandonment of the mine, the remaining supporting coal pillars in the goaf were affected by surrounding working faces, overburden loads, and other factors, resulting in certain damage and destruction. After the closure or abandonment of the mine, once a pressurized water accumulation environment is formed in the goaf, it will exacerbate the deterioration of the support performance of the coal pillar, which can lead to its destruction and instability, causing sudden surface collapse and other disasters. In order to study the coupling deterioration of initial damage and pressure water immersion on the remaining supporting coal pillars in closed or abandoned mines, based on the self-developed coal rock pressure water immersion test device, five groups of uniaxial compression tests on the pressure water immersion coal samples with different initial damages were conducted. Combined with the XTDIC three-dimensional full field strain measurement system, scanning electron microscope and other systems, the characteristics of coal sample strength, deformation failure and energy evolution were analyzed. The changes in mineral composition and other aspects reveal the deterioration mechanism of mechanical properties of coal samples. The research results indicate that: ① Based on the theory of viscoelastic plastic deformation of coal and rock, the dissipated energy generated by cyclic loading and unloading is subdivided into plastic damage energy and damping energy. The initial damage amount of coal and rock cyclic loading and unloading is redefined, and the average initial damage amount of five sets of coal samples is calculated to be 0, 0.071, 0.114, 0.205, and 0.309, respectively; ② The uniaxial compressive strength and elastic modulus of pressure water immersed coal samples are negatively correlated with the initial damage amount, while the pre-peak plastic deformation is positively correlated with the initial damage amount. As the initial damage increases, the stress concentration phenomenon at the defects of the coal sample becomes more significant, forming multiple deformation localization bands. The displacement change rate fluctuates sharply, and the failure mode of the coal sample changes from tensile failure to tensile shear mixed failure, resulting in an increase in the degree of fragmentation; ③ Under the coupling effect of initial damage and pressure water immersion, the internal pores and microcracks of the coal sample initiate and develop, the bonding force between particles decreases, and the internal structure transits from dense to loose porous. At the same time, the macroscopic cracks of the coal sample develop and expand, weakening the physical bearing structure of the coal sample. This is the fundamental reason for the deterioration of its mechanical properties, corresponding to a decrease in the energy storage capacity of the coal sample and a decrease in the strength of the post-peak failure dynamic manifestation. The above research has important theoretical significance for understanding the long-term stability and failure instability of the supporting coal pillars left in closed or abandoned mines.