不同岩性及含水率的岩石声波传播规律试验研究

利用智能声波仪对红砂岩、大理岩和花岗岩试样在干燥及饱和条件下进行了声波纵波透射试验，研究声波在岩石中传播的速度特征，同时利用傅里叶变换及小波变换研究声波在岩石中传播的波形、波幅衰减规律、波谱特征。结果表明： （1）红砂岩、大理岩和花岗岩在饱和状态下的纵波波速比其在干燥状态下略高。（2）岩石纵波速度受到岩石的致密程度、孔隙度、密度及硬度的影响。（3）在同样的激发信号下，饱水的砂岩、大理岩、花岗岩岩样声波信号能量集中在低频部分较多，而干燥岩样声波信号能量集中在高频部分较多。（4）饱水的3种岩样声波信号能量衰减较快，尾波不发育；干燥的3种岩样声波信号能量衰减较慢，尾波较发育。（5）穿过岩石的声波信号的波速、波形的时域特征、频域特征及时-频域特征能在一定程度上反映出岩石内部的孔隙及微裂隙的发育情况和岩石含水情况等特征。

Experimental study of propagation characteristics of acoustic wave in rocks with different lithologies and water contents

P-wave propagation tests of red sandstone, marble and granite samples were carried out under dry and water-saturated condition using nonmetal sonic wave testing system to study the velocity characteristics of P-wave propagation in different rocks. Rules of wave form, wave attenuation and wave spectrum were researched using Fourier and wavelet transforms. The experimental results indicate that: (1) The longitudinal wave velocities of red sandstone, marble and granite samples under water-saturated condition are slightly higher than those under dry condition. (2) P-wave velocity of rock samples are influenced by density, porosity and hardness. (3) With the same trigger signal, the energy concentrates on the low frequency band under water-saturated condition, and focuses on the high frequency band of the same samples under dry condition. (4) The energy of acoustic wave signals of the three kinds of samples under water-saturated condition attenuates rapidly, with plump coda wave. The energy of dry samples attenuates slowly, with shriveled coda wave. (5) The distribution of interior pores and microcracks and conditions of water contents in rock are reflected by the wave velocity and wave form of acoustic signal, which are presented in time, frequency and time-frequency domain.