华北地区四种岩石在高压下的破坏特征

FAILURE CHARACTERISTICS UNDER HIGH PRESSURE OF FOUR KINDS OF ROCKS TAKEN FROM NORTH CHINA

  • 摘要: 利用我国第一台1GPa高压三轴容器进行了岩石破坏实验.所用的样品为济南辉长岩、昌平花岗岩、房山大理岩和周口店石灰岩.得到的主要结果是:(1)在相应于地壳的压力范围内辉长岩和花岗岩仍然发生脆性破坏, 其强度和韧度随围压增加而增加, 破坏角也随围压增加而增大, 破坏前发生体积膨胀现象并出现声发射活动增加的前兆;(2)大理岩和石灰岩样品在0.1——0.8GPa的围压范围内发生鼓状变形, 不形成明显的主断层面, 样品承载能力随变形增加而增加, 出现应变硬化现象.在变形过程中声发射活动水平极低。这些实验标志着我国岩石力学三轴实验的围压水平有所提高其结果对震源物理的研究具有参考价值.

     

    Abstract: Experiments of rock failure were made by using the first 1 GPa triaxial high pressure vessel of our country. The samples were of Jinan gabbro, Changpin granite, Fangshan marble and Zhoukoudian limestone. The major results are: (1) In the pressure range corresponding to the crust, for gabbro and granite, brittle failure happens and the strength and the ductility increase with the confining pressure; the fracture angle increases with confining pressure too. Dilatancy takes place before failure and the precursor manifested by increase of AEactivity can be observed. (2) for samples of marble and limestone in the pressure range 0.1-0.8 GPa barrel deformation happens and visible major fault doesnt from. Loading capability increases with deformation and strain hardening takes place. During the process of deformation the level of AEactivity is very low. These experiments characterize that the confining pressure has been raised to a higher level in rock mechanical triaxial experiments, and may have reference value for study of the physics of seismic foci.

     

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