摘要
针对回采时反复采动作用下的保护层开采扰动煤岩极易诱发巷道围岩失稳的问题,采用分级循环荷载模拟实际回采工程中采动应力的长期作用,研究保护层开采扰动煤岩在循环荷载作用下的力学强度及变形破坏特性.试验结果表明,在加卸载过程中,受保护层开采扰动煤样的体积膨胀变形明显,煤样内部结构破坏程度比未受保护层开采扰动煤样更高.在加卸载后期,受保护层开采扰动煤样表现为塑性破坏,未受保护层开采扰动煤样发生明显的脆性破坏.相比于未受保护层开采扰动煤样,受保护层开采扰动煤样的峰值强度下降,单位体积(直径为50 mm,高度为100 mm)内的煤样裂隙体积显著增加,峰值强度和裂隙体积占比均沿煤层走向分布较为均匀.处于断层带的未受保护层开采扰动煤样的彼此物性差异较大.受保护层开采扰动煤样比未受保护层开采扰动煤样更符合“煤岩破坏时,裂隙空间复杂程度与峰值强度存在反向对应分布”规律.
Aimed the coal rock disturbed by the protective layer mining under the action of repeated mining during the recovery was likely to induce the destabilization problem of the roadway surrounding rock,the graded cyclic loading was adopted to simulate the long-term effects of mining stresses in the actual recovery projects,to investigate the mechanical strength and deformation damage characteristics of coal rock disturbed by protective layer mining under graded cyclic loading.Results show that the volume expansion deformation of the coal samples disturbed by the protective layer mining under the process of loading and unloading is obvious,the internal structure damage degree of the coal samples is higher than that of the coal samples undisturbed by the protective layer mining.In the later stage of loading and unloading,the coal samples disturbed by the protective layer mining show plastic failure,while the coal samples disturbed by the protective layer mining show obvious brittle failure.Compared with the coal samples undisturbed by the protective layer mining,the peak strength of the coal samples disturbed by the protective layer mining decreases,the fracture volume of the coal samples per unit volume(50 mm diameter and 100 mm height)increases significantly,and both the peak intensity and fracture volume ratio are distributed more uniformly along the coal seam direction.The physical properties of the coal samples undisturbed by the protective layer mining in the fault zone differ greatly from each other.The coal samples disturbed by protective layer mining is more in line with the law of“there is an inverse corresponding distribution between the complexity of coal rock fractures and the peak strength when coal rock is destroyed”than that of coal samples undisturbed by protective layer mining.
作者
杨永波
周哲
YANG Yong-bo;ZHOU Zhe(State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China;Chongqing Research Institute,China Coal Technology and Engineering Group,Chongqing 400037,China)
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2022年第12期2445-2453,共9页
Journal of Zhejiang University：Engineering Science
基金
国家自然科学基金资助项目(51625401,51774055)
中国平煤神马集团焦煤开发与综合利用国家重点实验室开放研究基金资助项目(41040220171106-1)。
关键词
开采扰动
循环荷载
峰值强度
裂隙重构
裂隙分布
三维裂隙分形维数
mining disturbance
cyclic loading
peak strength
fracture reconstruction
fracture distribution
three-dimensional fracture fractal dimension
作者简介
杨永波(1995-),男,工程师,硕士,从事煤岩采动力学及岩土力学研究.orcid.org/0000-0001-8944-4393.E-mail:yangyongbocqu@163.com;通信联系人:周哲,男,副教授,硕导.orcid.org/0000-0002-7992-9722.E-mail:zhouzhe@cqu.edu.cn。
