地震地质 ›› 1990, Vol. 12 ›› Issue (4): 311-315.

• 科研简报 • 上一篇    下一篇

三轴应力下花岗岩声发射P波Q值的变化

缪君, 许昭永, 韩明   

  1. 云南省地震局
  • 收稿日期:1989-04-30 出版日期:1990-12-11 发布日期:2009-11-25
  • 基金资助:
    地震科学基金

P-WAVE Q-VALUE OF ACOUSTIC EMISSION IN FRACTURE PROCESS OF GRANITE SPECIMENS UNDER TRUE TRIAXIAL COMPRESSION

Miao Jun, Xu Zhao-yong, Han Ming   

  1. Seismological Bureau of Yunnan Province, Kunming 650041
  • Received:1989-04-30 Online:1990-12-11 Published:2009-11-25

摘要: 50×50×100mm3盈江花岗岩样品在σ3=30MPa、σ2=60MPa时增加σ1直至破裂,用波传播和谱振幅比法测定破裂孕育过程中σ3方向和σ2方向声发射P波Q值。结果表明:1.在σ1<0.07σ1P(最大破裂压强)时,σ3、σ2方向都保持高值,在0.2σ1P≤σ1≤0.551P期间,两个方向的Q值呈现出比较平稳的状态,其平均值Q3大约10至20,σ2方向Q2大约20至30。在σ1>0.55σ1P后,σ3方向Q3值起伏增长较大,而σ2方向Q2值仅在σ1>0.7σ1P后,才起伏增长,幅度不如σ3方向大。2.随压力的增加,在σ3、σ2两方向,低频成分明显加大。3.当σ1>0.951P后,出现一种记录畸变现象,对同一源点声发射,从沿同一方向两道记录上看出,早到波形振幅小,而晚到波形其振幅反而大。

关键词: PQ值, 声发射, 谱振幅, 主破裂面

Abstract: Yinjiang granite specimens 50?50? 100mm3 in size are tested under true triaxial compressions of σ3=30 MPa,σ2=60MPa and increasing σ1 until the specimens fracture. We determined the P-wave Q-value of acoustic emission in σ3 and σ2 directions in the fracture process of specimens from the wave propagation and the spectral amplitude ratio. The obtained result shows that P-wave Q-vaiue and spectral amplitude of acoustic emission show their significant characteristic variation,which are anisotropic. We found an abnormal phenomenon:after σ1>0.95σIP,for the amplitudes of waves emitted from same source,those which are received by near probe are smaller,and those which are received by far probe are larger.

Key words: P-wave Q-value, Acoustic emission, Spectral amplitude, Fracture plane