摘要
考虑到实际工程中循环荷载的频率并非恒定值,设计不种频率固定振幅的正弦波加卸载单轴压缩试验,分析荷载频率对砂岩轴向变形和环向变形的影响规律,并结合声发射和能量演化规律探讨砂岩损伤机理。结果表明:荷载频率影响砂岩的变形过程、破坏形态和声发射特征,循环荷载下砂岩环向变形不仅形成滞回环,而且和轴向变形均经历相同的变形过程;0.1 Hz时砂岩变形经历初始阶段、等速阶段和加速阶段,而0.02 Hz和0.2 Hz下仅有初始阶段和等速阶段;在初始阶段砂岩均有声发射信号;在变形等速期时,声发射信号减弱;当变形进入加速阶段,外力功促使砂岩内微裂纹继续扩展,声发射信号逐渐增加,大量微裂纹贯通成宏观裂隙,最终形成多裂隙劈裂破坏模式。
Considering that the frequency of cyclic loading is not constant in practical rock engineering,uniaxial compression experiments with sinusoidal cyclic loading with a fixed amplitude at different frequencies were designed to investigate the effect of loading frequency on axial deformation and circumferential deformation of sandstone,and to explore the damage mechanism of sandstone by combining with the acoustic emission and the energy evolution law.The experimental results show that the loading frequency affects the deformation process,damage pattern and acoustic emission characteristics of sandstone.Under cyclic loading,the cyclic deformation of sandstone not only forms hysteresis loop,but also undergoes the same deformation process as axial deformation.At 0.1 Hz,sandstone deformation undergoes the initial stage,isochronous stage and accelerated stage,whereas only the initial stage and isochronous stage are found at 0.02 Hz and 0.2 Hz.In the initial stage,the sandstone has acoustic emission signals;in the isokinetic stage of deformation,the acoustic emission signals are weakened;when the deformation enters the acceleration stage,the external work promotes the further expansion of micro cracks in the sandstone,and the acoustic emission signal gradually increases.A large number of micro cracks penetrate into macroscopic cracks,ultimately forming a multi crack splitting failure mode.
作者
戚靖骅
赵春晓
李强
李玉寿
Qi Jinghua;Zhao Chunxiao;Li Qiang;Li Yushou(State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2024年第1期64-71,106,共9页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金(52274145)
中国矿业大学实验室开放基金(2021SYF67)。
关键词
循环荷载
岩石
变形
声发射
cyclic loading
rock
deformation
acoustic emission
