摘要
50×50×100mm^3盈江花岗岩样品在σ_3=30MPa、σ_2=60MPa时增加σ_1直至破裂,用波传播和谱振幅比法测定破裂孕育过程中σ_3方向和σ_2方向声发射P波Q值。结果表明:1.在σ_1<0.07σ_(1P)(最大破裂压强)时,σ_3、σ_2方向都保持高值,在0.2σ_(1P)≤σ_1≤0.55_(1P)期间,两个方向的Q值呈现出比较平稳的状态,其平均值Q_3大约10至20,σ_2方向Q_2大约20至30。在σ_1>0.55σ_(1P)后,σ_3方向Q_3值起伏增长较大,而σ_2方向Q_2值仅在σ_1>0.7σ_(1P)后,才起伏增长,幅度不如σ_3方向大。2.随压力的增加,在σ_3、σ_2两方向,低频成分明显加大。3.当σ_1>0.95_(1P)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。
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.
出处
《地震地质》
EI
CSCD
北大核心
1990年第4期311-315,共5页
Seismology and Geology
基金
地震科学基金
关键词
应力
花岗岩
声发射
P波
Q值
P-wave Q-value, Acoustic emission, Spectral amplitude, Fracture plane
