摘要
地下工程开挖导致的岩爆具有明显的滞后效应,研究显示,滞后型岩爆的发生与岩石的时滞性破坏密切相关,基于此,考虑开挖后围岩处于不同的应力水平,进行了时滞性单轴压缩试验,详细分析不同应力水平下岩石的时滞性变形破坏特征。研究结果表明:应力水平对岩石的时滞性变形破坏影响显著,随着应力水平的提高,破坏孕育时间呈指数衰减,但远超过常规单轴压缩破坏的孕育时间;时滞性单轴压缩破坏时,岩样的环向应变和体积应变明显大于常规单轴压缩试验,而且应力水平低于90%时,破坏时的环向应变迅速增长并超过了轴向应变,这也是时滞性破坏区别与常规单轴压缩破坏的显著特征;时滞性单轴压缩破坏时的总能量与常规单轴压缩总体相当,但时滞性加载过程中,耗散能所占的比重明显增加,说明时滞性加载阶段会导致岩石内部的损伤显著发育;时滞性加载阶段岩样环向应变的快速增长导致近轴向劈裂张拉破坏裂纹显著增加,这也导致岩样破坏的碎裂程度更加严重。相关研究成果可为岩石在高应力水平下损伤破坏的时效性及时滞性岩爆分析解释提供较好的参考。
Rockburst caused by underground engineering excavation has obvious time-lag effect. Previous research shows that the occurrence of hysteresis rockburst is closely related to the time-lag damage of the rock. Based on this, considering that the surrounding rock is at different stress levels after excavation, the time-delay uniaxial compression test is carried out to analyze the time-delay deformation and failure characteristics of rocks under different stress levels. The results show that the stress level has a significant impact on the time-delay deformation and failure of rocks. As the stress level increases, the failure incubation time decreases exponentially, but it is much longer than that of conventional uniaxial compression failure. In the case of delayed uniaxial compression failure, the hoop strain and volume strain of the rock sample are significantly greater than that of conventional uniaxial compression test, and when the stress level is lower than 90%, the hoop strain at failure rapidly increases and exceeds the axial strain,which is also the distinguishing feature of time-lag failure and conventional uniaxial compression failure. The total energy of delayed uniaxial compression failure is equivalent to that of conventional uniaxial compression, but the proportion of dissipated energy increases significantly in the process of delayed loading, indicating that the delayed loading stage will lead to the significant development of damage in the rock. The rapid growth of circumferential strain of rock samples in the stage of time-delay loading leads to the significant increase of near axial splitting tensile failure cracks, which also leads to the more serious fragmentation of rock samples. The relevant research results can provide a good reference for the analysis and interpretation of time-dependent and time-lag rockburst of rock damage and failure under high stress level.
作者
徐鹏飞
邓华锋
张恒宾
彭萌
李冠野
姜桥
陈兴周
XU Peng-fei;DENG Hua-feng;ZHANG Heng-bin;PENG Meng;LI Guan-ye;JIANG Qiao;CHEN Xing-zhou(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University,Yichang,Hubei 443002,China;Wudongde Engineering Construction Department of China Three Gorges Construction Management Co.,Ltd.,Chengdu,Sichuan 610000,China;College of Architecture and Civil Engineering,Xi’an University of Science and Technology,Xi’an,Shaanxi 710054,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2021年第11期3041-3050,3078,共11页
Rock and Soil Mechanics
基金
国家自然科学基金资助项目(No.U2034203,No.51979218)
三峡大学2019级硕士学位论文培优基金(No.2021SSPY020)。
关键词
时滞性
应力水平
变形特征
耗散能
破坏形态
time lag
stress level
deformation characteristics
dissipated energy
failure mode
