低围压和疲劳载荷下砂岩的波速、模量及疲劳损伤(I):岩石的声学特性

WAVE VELOCITIES,MODULUS,FATIGUE DAMAGE OF SANDSTONE UNDER LOW CONFINING PRESSURE AND CYCLIC LOADING(I):ACOUSTICS CHARACTERISTICS OF ROCK

在温度为室温至125℃、围压为30 MPa、轴压为40.7 MPa、正弦波频率为0.05～5 Hz、正弦波振幅为5.1 MPa条件下进行了三轴动载疲劳实验。实验结果说明:弹性波速度VP,VS和杨氏模量E随温度的升高先下降而后升高,随频率对数的增高而增高,具有频散效应;波速比随温度升高波动大,无规律可循,随频率升高明显下降。这些可作为地震或其他疲劳损伤的前兆。

Triaxial dynamic fatigue tests are conducted on sandstone under temperature of 30℃～125℃,confining pressure of 30 MPa and axial pressure of 40.7 MPa,with sine-wave frequency 0.05～5 Hz and its amplitude of 5.1 MPa. The results indicate that elastic wave velocities VP,VS and Youngs modulus E of sandstones are all decreased and then increased with temperature,and they display strong dispersion effect with frequency. There exists a large variation of velocity with temperature and frequency, which can be applied as the omens of earthquake or fatigue damage.