多次采掘扰动煤体力学特性演化规律试验研究  

An experimental study of the evolutionary patterns of mechanical properties of coals under multiple mining disturbances

作　　者：欧阳振华 刘洋 李春雷[3] 史庆稳 李文帅 易海洋 秦洪岩 张宁博 OUYANG Zhenhua;LIU Yang;LI Chunlei;SHI Qingwen;LI Wenshuai;YI Haiyang;QIN Hongyan;ZHANG Ningbo(School of Mine Safety,North China Institute of Science and Technology,Langfang 065201,China;School of Mechanics&Engineering,Liaoning Technical University,Fuxin 123000,China;China Institute of Water Resources and Hydropower Research,Beijing 100048,China)

机构地区：[1]华北科技学院矿山安全学院,河北廊坊065201 [2]辽宁工程技术大学力学与工程学院,辽宁阜新123000 [3]中国水利水电科学研究院,北京100048

出　　处：《煤田地质与勘探》2024年第10期72-84,共13页Coal Geology & Exploration

基　　金：国家自然科学基金面上项目(52274120);河北省自然科学基金重点项目(E2024508004);河北省教育厅科学技术研究项目(BJK2022067);廊坊市科技计划项目(2023013164,2023013209)。

摘　　要：【目的】矿井开采过程中,多次采掘扰动所引发的循环加卸载效应对煤体力学性能的改变是导致冲击地压灾害发生的原因之一。揭示煤体在此过程中的关键力学参数响应特征及损伤机制可为冲击失稳状态判别提供依据,对提升灾害预测能力具有重要意义。【方法】采用大尺寸类煤体试样,将准静态单轴循环加卸载和冲击动载相结合,精确捕捉试验过程中试样应力、应变以及声发射等响应信息,全面揭示多次采掘扰动作用下试样力学参数变化规律及损伤演化过程。【结果和结论】结果表明:(1)最高加载载荷是影响多次循环加卸载作用下损伤煤体力学性能的最关键因素,随着循环次数的增加,对于加载至屈服阶段的试样,其残余应变呈现先增大后减小再增大的变化趋势,耗散能密度及加载至最高载荷时所对应的声发射特征值逐渐增大,试样损伤程度不断增加;对于加载至弹性阶段的试样,其上述力学特征参数均呈现先减小后增大的变化趋势;而对于试验过程始终处于压密阶段的试样,3组数据均呈现不断减小的变化趋势。(2)在施加冲击动载作用后,3组试样均发生冲击破坏,前期准静态循环加卸载试验中所受载荷越小的试样,其损伤程度越小,发生冲击破坏所需的诱发动载强度越大,峰值破坏弹性模量越大。(3)从应变与能量2个角度对试样损伤度进行表征,通过对比分析,发现能量损伤度对此试验过程中试样损伤程度判别更为敏感。(4)对试样孔洞内部冲击破裂特征观察发现,试样在发生冲击破坏过程中共经历平静期、颗粒弹射期、稳定破坏期以及冲击破坏期4个阶段。(5)可将循环加卸载后期残余应变增大起始值以及冲击破坏过程中稳定破坏前期阶段作为损伤煤体冲击失稳前兆预警信息。研究获得了受多次采掘扰动煤体力学特性的演化规律,可为工程中损伤煤体冲击失稳�[Objective]In the mining process of coal mines,the the cyclic loading and unloading effects caused by multiple mining disturbances can alter the mechanical properties of coals,serving as a significant cause of rock bursts.Revealing the response characteristics of crucial mechanical parameters and the damage mechanisms of coals can provide a basis for discriminating the impact-induced instability state,holding great significance for enhancing disaster prediction cap-abilities.[Methods]Quasi-static uniaxial cyclic loading and unloading experiments and the dynamic impact loading ex-periments on large-size coal-like specimens were combined to accurately capture the stress,strain,and acoustic emis-sion responses during the experiments,thoroughly unveiling the laws of changes in mechanical parameters and the dam-age evolutionary processes of the specimens under the action of multiple mining disturbances.[Results and Conclu-sions]Key findings are as follows:(1)The maximum load is identified as the most critical factor influencing the mech-anical properties of the coals damaged by multiple cyclic loading and unloading processes.With an increase in the num-ber of cycles,the specimen in the yield stage under loading displayed increasing,decreasing,and then increasing resid-ual strain.Meanwhile,it exhibited gradually increasing dissipated energy density and acoustic emission characteristic value corresponding to the maximum load,suggesting escalating damage degrees of the specimens.For the specimen in the elastic stage under loading,all the mechanical parameters mentioned above first decreased and then increased.In contrast,for the specimen remaining in the compaction stage throughout the experiment,the three sets of data manifes-ted gradually decreasing trends.(2)Under dynamic impact loading,all of the three specimens experienced impact-in-duced failure.The specimen subjected to a lower load in the earlier quasi-static cyclic loading and unloading experi-ments exhibited less damage,higher dynamic load strength required for

关 键 词：煤矿安全 采掘扰动 冲击动载 声发射 力学特性 损伤机制 损伤度 预警信息 

分 类 号：TD324[矿业工程—矿井建设]