摘要
含煤建造的成层及层理特性使得围岩更多地体现为剪切灾变。为进一步探究循环荷载条件下煤岩体的剪切破坏行为,采用等幅循环与逐级一次循环加卸载方式,并联合CT扫描开展了砂质泥岩的单轴压缩试验。通过岩样破裂形态及全过程应力–应变曲线,分析了岩样剪切破坏显现的“多米诺骨牌”构造及其演进特征。结果表明:单轴等幅、逐级一次循环加卸载下,岩样均发生剪切破坏,且逐级一次加卸载循环下岩样破坏形成的剪切破碎带包括若干呈“多米诺骨牌”构造的应变局部化带,破坏过程对应的应力–应变曲线呈特殊的滞回–往复–滞回–往复状振荡波动;应变局部化带呈现成核、启裂、外扩、衰损、传导的演化过程;具有“多米诺骨牌”构造的碎裂块体发生旋转–回旋运动,使峰后输入能量及弹性储能在块体相互摩擦中多级耗散,延长了破坏时长,具有显著的“缓释”效应。剪切破裂形态演化与应力–应变隐蔽信息相互协同,共同将剪切破坏过程划分为6个破坏阶段,分别为:裂缝启裂微扩展(Ⅰ)、裂缝初始扩展(Ⅱ)、主剪切裂缝扩展(Ⅲ)、裂缝扩展亚稳态(Ⅳ)、裂缝快速扩展(Ⅴ)和加速破坏(Ⅵ)。“多米诺骨牌”构造是剪切破坏的一种特有形式,其所起到的能量“缓释”效应可能是煤矿巷道利用围岩自身结构进行卸压护巷的一个新思路。
The stratification and bedding characteristics of the coal-bearing construction make the surrounding rock more occur a shear disaster.To further investigate the shear fracture behaviour of coal rock masses under cyclic loading conditions,uniaxial compression tests on sandy mudstone were carried out using constant amplitude cyclic and stepwise linear cyclic loading and unloading methods in conjunction with CT scanning.The“Domino”structure of shear rupture of rock samples and its evolutionary characteristics were analysed by means of the rupture morphology and the stress-strain curve of the whole process.The results show that,under uniaxial compression and constant amplitude cycles and stepwise linear cycles,shear failure occurs in all rock samples.Moreover,the shear fracture zone formed by the failure of rock samples under stepwise linear loading and unloading cycles includes several strain localization zones with a“Domino”structure,and the stress-strain curve corresponding to the failure process shows a special“hysteresis-reciprocation-hysteresis-reciprocation”oscillation fluctuation.The strain localization zone presents the evolution process of nucleation,initiation crack,expansion,decay and conduction.The rotating-gyration motion of the fragmented block with the“Domino”structure causes multi-stage dissipation of the input energy and elastic storage energy after the peak in the friction of the block,which prolongs the damage time and has a significant“slow release”effect.The shear crack morphological evolution and stress–strain concealment information cooperate with each other to divide the shear failure process into six failure stages,namely:crack initiation micropropagation(I),crack initial propagation(II),primary shear crack propagation(III),Crack propagation metastable(IV),rapid crack propagation(V),accelerated failure(VI).The“Domino”structure is a unique form of shear failure,and the energy“slow release”effect it plays may be a new idea for coal mine roadways to use the surroun
作者
刘向御
柴肇云
肖畅
沈玉旭
辛子朋
李天宇
孙浩程
闫珂
刘新雨
段碧英
LIU Xiangyu;CHAI Zhaoyun;XIAO Chang;SHEN Yuxu;XIN Zipeng;LI Tianyu;SUN Haocheng;YAN Ke;LIU Xinyu;DUAN Biying(Key Laboratory of In-situ Property-Improving Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2024年第1期170-183,共14页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(52274091,51974193)。
