低频扰动下高应力砂岩非线性动态力学响应特征  

Nonlinear mechanical dynamic response characteristics of high stress sandstone subject to low frequency disturbance

作　　者：文晓泽 冯国瑞[1,2] 郭军 王朋飞[1,2] 白锦文 钱瑞鹏 于露杨[1,2] 张洁 张鹏飞 WEN Xiaoze;FENG Guorui;GUO Jun;WANG Pengfei;BAI Jinwen;QIAN Ruipeng;YU Luyang;ZHANG Jie;ZHANG Pengfei(College of Mining Technology,Taiyuan University of Technology,Taiyuan 030024,China;Key Laboratory of Shanxi Province for Mine Rock Strata Control and Disaster Prevention,Taiyuan 030024,China;Shanxi Cooking Coal Group Co.,Ltd.,Taiyuan 030024,China;State Key Laboratory of Hydroelectric and Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]矿山岩层控制及灾害防控山西省重点实验室,山西太原030024 [3]山西焦煤集团有限责任公司,山西太原030024 [4]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《煤炭学报》2024年第9期3810-3828,共19页Journal of China Coal Society

基　　金：国家杰出青年科学基金资助项目(51925402);国家自然科学基金重点资助项目(52334005);山西省科技重大专项资助项目(20201102004)。

摘　　要：受煤矿残采区上行开采扰动影响,层间岩层在高静应力和低频扰动荷载耦合作用下的失稳是引发遗煤资源复采动力灾害的主要原因之一。为研究低频扰动荷载作用下高应力状态岩石的动态响应特征,以煤系地层砂岩为研究对象,基于自主研发的动静载耦合电液伺服试验机,开展不同幅值低频扰动荷载(5 Hz)作用下高应力砂岩(80%单轴抗压强度(UCS))动态单轴压缩试验,揭示了低频扰动下高应力砂岩的裂纹演化规律、渐进损伤行为和非线性动态响应特征。结果表明:①小幅扰动荷载作用过程中高应力状态砂岩并不会失稳,80%UCS预静载状态下诱使砂岩发生破坏的低频扰动幅值门槛值为15%UCS,在越过应力门槛值的扰动荷载作用过程中,高应力砂岩破坏前的扰动荷载循环周期数随幅值增大指数型衰减。②在砂岩内部随机分布的微裂纹萌生和渐进扩展影响下,动态割线模量、峰值应变、耗散能密度和声发射b值随扰动荷载作用时间的非线性演化特征显著。③指数型应变演化曲线在砂岩破坏前有明显的拐点,可以作为低频扰动下高应力砂岩动态破坏的前兆信息,用于相应动力灾害预警。④在越过门槛值的低频扰动荷载作用过程中,动态割线模量演化曲线近似指数型衰减,且非线性拟合参数可以用以量化割线模量劣化速率,砂岩的割线模量劣化速率随幅值线性递增非线性变化。⑤扰动荷载作用初期的上升时间和幅值的比值(RA)可以用于砂岩动态破坏超前预测,相应地,扰动荷载作用过程中RA的突增可以作为砂岩动态破坏的前兆预警信息。未越过门槛值的低频扰动荷载作用过程中,砂岩微破裂以张拉或混合破裂为主,剪切破裂占比仅为12.15%;幅值为15%UCS、20%UCS和25%UCS的扰动荷载作用过程中,剪切破裂占比分别为37.17%、52.75%和53.62%,随扰动荷载幅值增大对数型增加。The mechanical response characteristics of rock under low-frequency perturbation loads and high-stress conditions are important factors affecting the stability of interlayer rock in the goaf during upward mining.Taking the coal-bearing sedimentary rock sandstone as the research object,the dynamic uniaxial compression tests were conducted on highstress sandstone(80%UCS)under low-frequency perturbation loads(5 Hz)using a self-developed dynamic-static coupled electro-hydraulic servo testing machine.The progressive damage behavior and nonlinear mechanical dynamic response characteristics of high-stress rock under low-frequency perturbations were revealed.The results are as follows:①During the process of small amplitude low-frequency disturbance load,high-stress sandstone does not experience dynamic failure,the threshold value of low-frequency disturbance load amplitude to induce sandstone damage is 15%UCS.Under the action of low-frequency disturbance load above the threshold value,the number of disturbance load cycles before the failure of high-stress sandstone decreases exponentially with the increase of amplitude.②The progressive initiation and accumulation of randomly distributed microcracks within the sandstone,as well as their gradual extension,significantly affect the nonlinear evolution characteristics of dynamic secant modulus,strain peak,plastic deformation,dissipated energy density,and b-value.③During the low-frequency perturbation process,the b-value and dissipated energy density exhibit a threestage evolution characteristic consistent with the strain.The exponential strain evolution curve has a distinct inflection point before the failure of the sandstone,which can serve as a precursor information of dynamic failure under low-frequency perturbations and be used for corresponding dynamic disaster warnings.④During the low-frequency perturbation load process beyond the threshold,the dynamic secant modulus evolution curve approximates an exponential decay.The parameters in the nonlinear fitting relati

关 键 词：低频扰动 高应力 渐进损伤 非线性响应 

分 类 号：TD350[矿业工程—矿井建设]