地震地质 ›› 1996, Vol. 18 ›› Issue (3): 277-281.

• 科研简报 • 上一篇    下一篇

在真三轴压缩条件下片麻岩破裂孕育过程中弹性波的特征变化

赵晋明1, 胡毅力2, 王彬3, 许昭永3   

  1. 1. 云南省地震局, 昆明 650041;
    2. 云南大学地球科学系, 昆明 640041
  • 收稿日期:1995-01-31 修回日期:1995-11-30 出版日期:1996-09-04 发布日期:2009-11-25

VARIATION CHARACTERISTICS OF ELASTIC WAVE DURING THE FRACTURE-PREPARING PROCESS OF GNEISS UNDER TRUE TRIAXIAT COMPRESSION

Zhao Jinming1, Hu Yili2, Wang Bin3, Xu Zhaoyong3   

  1. 1. Department of Geoscience of Yunnan University, Kunming 650091;
    2. Seismological Bureau of Yunnan Province, Kunming 650041
  • Received:1995-01-31 Revised:1995-11-30 Online:1996-09-04 Published:2009-11-25

摘要: 片麻岩在真三轴压缩至主破裂的孕育过程中,沿σ3方向(与主破裂面斜交)的弹性波有显着的特征变化;P波、S波的初至波走时变化呈现略高~平稳~高值~(回降)的形式,走时比呈现平稳~低值~回升的变化特征。振幅呈现低值~平稳高值~下降~(低值)变化形态,振幅比呈现相对稳定~甚高值~回降变化形态。波列振幅衰减系数呈现稳定值~低值~回升变化形态。微裂隙的开闭和P,S波的非同步变化及相对变化量的不同是上述特征变化的主要原因。

关键词: 三轴压缩试验, 破裂过程, 弹性波, 片麻岩

Abstract: During the preparing process from compression to fracture,the elastic waves of gneiss have obvious various characteristics along the σ3 direction( obliquely crossing with main fracture plane): the various state of the first arrival time of P,S wave shows a shape of relatively high value~stability~high value~decrement,and the ratio of trave time has shape of stabiltity~low value~increment. The amplitude of P,S waves shows a shape of low value~stability high value decrement(low value) and their ratios have a shape of relatively stabllty~very high value~decrement. The variation state of attenuation coefficient of the wave trian shows a shape of stability~low value~increment.The main reason for those variations is the openingand closing of micro-cracks,the nonsynchronous variation of P, S wave and the difference of their variations.

Key words: Triaxial compression test, Rupture process, Elastic wave, Gneisse