摘要
为研究不同应力上限及加载频率条件下软弱红层泥岩的损伤及变形特性,基于声发射损伤监测手段开展高周循环加卸载试验,系统分析应力上限与加载频率对红层泥岩损伤及裂纹扩展模式的影响。结果表明:当应力上限低于屈服临界动应力值时,泥岩经历先剪缩后缓慢剪胀的过程,岩样中微裂隙的发展与黏土矿物的膨胀逐渐占据主导地位;低频AE信号产生于静载阶段,而高频AE信号主要出现在循环加载阶段,且随加载频率的增大,超过300 kHz的超高频声AE信号占比逐渐增大;红层泥岩循环荷载下所产生的裂纹总体以张拉裂纹为主,但第I阶段剪切裂纹占比相对其他阶段较大,且随着动应力幅值减小或加载频率的增大,剪切裂纹所占比例减小;在裂隙自愈合效应下,泥岩中由动载引起的损伤裂隙会被逐渐修复,且随着放置时间的增加,声发射Kaiser效应逐渐减小甚至消失。
A high-cycle cyclic loading test was conducted using acoustic emission(AE)monitoring techniques to investigate the damage and deformation characteristics of soft red mudstone under different upper stress limits and loading frequencies.Based on the analysis of AE parameters,the influence of dynamic stress limits and loading frequency on the damage and crack propagation patterns of the red mudstone were systematically studied.The results showed that when the dynamic stress limit was lower than the critical dynamic yield stress value,the mudstone underwent a process of initial shear contraction followed by slow shear dilation.The development of microcracks in rock samples and the expansion of clay minerals gradually became dominant.Low-frequency AE signals were generated during the static loading phase,while high-frequency AE signals primarily occurred during the cyclic loading phase.Moreover,with an increase in loading frequency,the proportion of ultra-high-frequency AE signals exceeding 300 kHz gradually increased.The cracks produced in the red mudstone under cyclic loading were primarily tensile cracks.Among them,shear cracks in the first stage(Stage I)accounted for a relatively larger proportion compared to other stages.However,the proportion of shear cracks decreased as the dynamic stress amplitude decreased or the loading frequency increased.Due to the self-healing effect of cracks,the damage-induced cracks caused by dynamic loading were gradually repaired within the mudstone.Additionally,as the elapsed time increased,the Kaiser effect associated with AE gradually diminished and even disappeared.
作者
于天佑
蒋关鲁
饶千竺
陈虹羽
吴霖
刘先峰
YU Tianyou;JIANG Guanlu;RAO Qianzhu;CHEN Hongyu;WU Lin;LIU Xianfeng(School of Civil Engineering,Southwest Jiaotong University,Chengdu Sichuan 610031,China;Key Laboratory of High-Speed Railway Engineering,Southwest Jiaotong University,Ministry of Education,Chengdu Sichuan 610031,China;School of Civil Engineering,Xinjiang Institute of Engineering,Urumqi Xinjiang 830023,China)
出处
《中国铁道科学》
EI
CAS
CSCD
北大核心
2024年第1期12-25,共14页
China Railway Science
基金
国家自然科学基金资助项目(52378463)
国家重点研发计划项目(2022YFE0104600)
四川省国际科技创新合作项目(2021YFH0024)。
关键词
红层泥岩
循环荷载
声发射参数分析
裂纹扩展模式
裂隙自愈合效应
Soft red mudstone
Cyclic loading
Acoustic emission parameter analysis
Crack growth mode
Crack self-healing effect
作者简介
第一作者:于天佑(1995—),男,山西吕梁人,博士研究生。E-mail:tyyu@my.swjtu.edu.cn;通讯作者:蒋关鲁(1962—),男,浙江杭州人,教授,博士研究生导师,博士。E-mail:wgljiang@swjtu.edu.cn。
