随着煤炭开采深度的增加，地下工程所面临的环境也变得愈加复杂，巷道大变形、岩爆、冲击地压等围岩工程灾害不断出现，严重影响着我国煤炭资源的安全生产，实时掌握并获取围岩内部应变场损伤信息是防治围岩灾害的关键，因此研究煤岩受载过程中变形破坏机制和失稳前兆信息识别意义重大。本文通过开展室内岩石力学实验，研究实验室尺度下受载煤体变形损伤过程中的光纤-声发射响应特征，揭示了煤体内部变形损伤的演化规律，并对煤体失稳破坏的应变和声发射前兆信息进行了识别研究。主要取得以下成果：

（1）光纤传感技术（OFDR）能够实现煤体内部应变的高精度分布式测量，可以精细地复刻煤体内部不同位置的应变场演化过程，获取应变集中出现的时间和应变集中区域。声发射信号强度与加载路径具有相关性，并且在煤体破坏前存在短暂的“平静期”，期间声发射振铃计数、能量、幅值都有降低。

（2）基于煤体受载后非均匀变形的特性，提出了非均匀变形指标S_w和损伤程度指标D_i量化煤体受载过程中的变形损伤程度。非均匀变形指标S_w可以表征煤体局部位置的变形损伤，而损伤程度指标D_i只适用于煤体整体变形损伤的表征。非均匀变形指标S_w和损伤程度指标D_i的演化曲线急增，出现拐点时可作为煤体破坏的预警前兆信息，D_i与S_w演化曲线整体趋势较相似，但在压密阶段和弹性阶段D_i趋势更明显，屈服阶段S_w演化特征表现更强烈。

（3）基于煤体受载后声发射参数的响应特征，进一步分析了声发射b值和信息熵在整个加载阶段的演化规律，发现声发射b值大致呈“波动-稳定-下降”的变化趋势，b值的持续下降可作为煤体破坏前兆信息；声发射熵值大致呈“增大-稳定-增大-稳定”的变化趋势，信息熵由平稳变化转为急剧增长预示着煤体即将破裂。

（4）基于临界慢化理论，获得了试样内部应变和声发射振铃计数的破坏前兆信息。基于应变和声发射振铃计数的方差前兆点均可对煤体破坏有效预警。光纤更适合监测煤体局部失稳破坏，应变方差前兆点出现时间的差别越大，煤体更易发生局部破坏，差别越小煤体发生整体破坏的概率越大。基于声发射的破坏前兆研究更适用于试样整体变形损伤监测，但预警时间相较于应变的破坏前兆时间略晚。

本文的研究内容为煤岩变形损伤的研究提供了一种新的监测方法和手段，同时也为煤岩破坏前兆信息识别提供了新思路，具有一定的科学意义和工程指导意义。

With the increase of coal mining depth, the environment faced by underground engineering has become increasingly complex. Surrounding rock engineering disasters such as large deformation of tunnels, rock bursts, and rockburst continue to occur, seriously affecting the safe production of coal resources in China. Real time grasping and obtaining information on the internal strain field damage of surrounding rock is the key to preventing and controlling surrounding rock disasters. Therefore, studying the response characteristics of deformation damage during the loading process of coal and rock and identifying precursor information of instability and failure is of great significance. This article conducts indoor rock mechanics experiments to study the fiber optic acoustic emission response characteristics during the deformation and damage process of loaded coal at the laboratory scale, revealing the evolution law of internal deformation and damage of coal, and identifying the strain and acoustic emission precursor information of coal instability and failure. The main achievements are as follows:

(1) Fiber optic sensing technology (OFDR) can achieve high-precision distributed measurement of internal strain in coal, accurately replicate the evolution process of strain fields at different positions inside the coal, and obtain the time and area of strain concentration. The intensity of acoustic emission signals is correlated with the loading path, and there is a brief "calm period" before coal failure, during which the acoustic emission ringing count, energy, and amplitude all decrease.

(2) Based on the characteristics of non-uniform deformation of coal under load, the non-uniform deformation index Sw and damage degree index Di are proposed to quantify the degree of deformation and damage during the loading process of coal. The non-uniform deformation index Sw can characterize the deformation damage at local positions of the coal body, while the damage degree index Di is only applicable to the characterization of the overall deformation damage of the coal body. The evolution characteristics of Sw and Di at different loading stages were analyzed. When their evolution curves suddenly increase, they can serve as warning signs of coal failure. The overall trend of the evolution curves of Di and Sw is similar, but the trend of Di is more obvious in the compaction stage and elastic stage, and the evolution characteristics of Sw are stronger in the yield stage.

(3) Based on the response characteristics of acoustic emission parameters after coal loading, the evolution law of acoustic emission b-value and information entropy during the entire loading stage was further analyzed. It was found that the acoustic emission b-value roughly showed a trend of "fluctuation stability decrease", and the continuous decrease of b-value can serve as precursor information for coal failure; The entropy value of acoustic emission roughly shows a trend of "increasing stable increasing stable", and the information entropy changes from stable to rapid growth, indicating that the coal body is about to fracture.

(4) Based on the critical slowing down theory, the failure precursor information of the internal strain and acoustic emission ringing count of the sample is obtained. The variance-precursory points based on strain and acoustic emission ringing count can be used for effective early warning of coal mass failure. The optical fiber is more suitable for monitoring local instability failure of coal. The greater the difference in the occurrence time of strain variance precursor points, the more likely local failure of coal is to occur, and the smaller the difference, the greater the probability of overall failure of coal. The study of the failure precursor based on acoustic emission is more suitable for the whole deformation damage monitoring of the sample, but the warning time is slightly later than that of the strain.

The research content of this article provides a new monitoring method and means for the study of coal rock deformation damage, and also provides a new idea for identifying precursor information of coal rock failure, which has certain scientific and engineering guidance significance.

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