• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
等幅循环加载岩石变形局部化带位移演化规律
  • Title

    Displacements evolution laws of deformation localization bands of rock under constant amplitude cyclic loading

  • 作者

    杨小彬韩心星王逍遥张子鹏

  • Author

    YANG Xiaobin1,2 ,HAN Xinxing1,2 ,WANG Xiaoyao1,2 ,ZHANG Zipeng1,2

  • 单位

    中国矿业大学(北京)资源与安全工程学院共伴生能源精准开采北京市重点实验室

  • Organization
    1. School of Resource and Safety Engineering,China University of Mining and Technology (Beijing),Beijing  100083,China; 2. Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources,Beijing  100083,China
  • 摘要

    岩石是一种非均质天然工程材料,在工程中往往处于一种循环往复加载状态之中,研究循环加载过程中岩石的变形局部化演化规律,为岩土工程结构的稳定性提供理论支持。将循环加载简化为等幅循环和分级等幅循环2种加载条件,开展红砂岩试件的2种循环加载方式下的实验研究,采用CCD(Charge-Coupled Device)相机对试验过程中试件的变形图像进行采集,基于数字散斑相关方法分析了等幅循环加载过程中试件变形局部化带位移演化规律。分析发现:循环加载全过程中,局部化带位移随加卸载应力呈现波动上升变化;相对于加载应力的变化,位移演化存在时间滞后性,且随着循环次数的增加位移存在明显的累积效应。循环加卸载过程中,局部化带位移顶点相对于加载应力顶点的滞后时间数值于循环前期呈平稳波动、循环后期呈上升波动;局部化带位移底点相对于卸载应力底点的滞后时间数值随循环次数的增加呈现平稳波动。整个循环过程中,当加载或卸载到同一应力水平时,局部化带的位移随着循环次数的增加而增大;每次循环过程中的同一应力水平下,卸载过程的位移数值大于加载过程的位移数值。随着循环次数的增加,局部化带位移存在明显的缓慢演化阶段和加速演化阶段。在试件破坏前,卸载底点处的局部化带位移值明显趋近于加载顶点处的局部化位移值,该局部化带位移演化特征可以作为循环加载过程中岩石试件或结构失稳破坏的一个前兆信息。研究可为循环荷载下的岩土工程材料或结构的失稳破坏提供新的特征力学监测量,即在某一特定应力环境中,当低应力状态的变形量值与相对高应力状态的变形量值都随时间发生增大且低应力对应的变形量值增加速率明显大于高应力对应的变形量值增加速率时,岩土材料或结构将会发生失稳破坏。

  • Abstract
    Rock is a kind of heterogeneous natural engineering material. Rocks in geotechnical engineering are often in a cyclic loading state. Investigation into the localization evolution law of rock deformation under cyclic loading can pro- vide theoretical support for the stability of geotechnical engineering structures. The study simplified the cyclic loading conditions as one constant amplitude cyclic loading condition and one graded constant amplitude cyclic condition. The tests of red sandstone specimens were carried out under the two cyclic loading conditions. The deformation images of specimens during the tests were collected by CCD camera,and based on the digital speckle correlation method,the dis- placements evolution laws of deformation localization bands of specimens during constant amplitude cyclic loading were analyzed. The analysis finds that during the whole process of cyclic loading,the displacements of localization bands fluctuate upward with the loading and unloading stress. There is a time lag for the displacements relative to the stress change,and with the increase of cyclic number,there is a cumulative effect for the displacements. In the cycle,the val- ues of lag time at the vertexes of the displacements of localization bands fluctuate steadily at the early stage of cycle and fluctuate upward at the later stage of cycle relative to the vertexes of loading stress. The values of lag time at the bottom point of the displacements of localization bands fluctuate steadily with the increase of cyclic number relative to the bottom point of unloading stress. When loading or unloading to the same stress in the whole cycle,the displace- ments of localization bands increase with the increase of cyclic number respectively. The displacements of unloading process are greater than those of loading process under the same stress during each cycle. With the increase of cyclic number,the displacements of localization bands experience slow evolution stage and accelerated evolution stage obvi- ously. Before the failure of specimens,the displacement values of localization bands at the bottom point of unloading will be evidently close to the displacement values at the vertex of loading,and this phenomenon can be used as a pre- cursor information of the instability failure of rock specimens or rock structures under cyclic loading station. The re- search in this paper can provide a new characteristic mechanical monitoring quantity for the instability failure of geotechnical engineering materials or structures under cyclic loading. That is,in a particular stress environment,when the deformation value of low stress state and relative high stress state both increase with time and the increase rate of the deformation value corresponding to low stress is obviously greater than that corresponding to high stress,the failure of geotechnical materials or structures will occur.
  • 关键词

    等幅循环加载局部化带位移时间滞后累积效应前兆信息

  • KeyWords

    constant amplitude cyclic loading;displacements of localization bands;time lag;cumulative effect;precur- sor information

  • 基金项目(Foundation)
    国家自然科学基金资助项目(51274207);国家自然科学基金青年基金资助项目(50904071)
  • DOI
  • Citation
    YANG Xiaobin,HAN Xinxing,WANG Xiaoyao,et al. Displacements evolution laws of deformation localization bands of rock under constant amplitude cyclic loading[ J]. Journal of China Coal Society,2019,44(4):1041 -1048.
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主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会

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