【摘要】 基于岩石的声弹理论,通过脉冲回波方法测量双轴加载条件下沿薄板岩样厚度方向传播的超声纵、横波波速变化,来测定岩石的三阶弹性模量。试验结果表明:将横波和纵波传感器放置于岩样中心部位的相对表面上,测量同一地点的纵、横波波速,不仅减弱了双向加载端部效应,而且克服了岩石的非均质性对测量结果的影响。此外,通过脉冲回波方法测量多次回波信号的时间差,来克服耦合剂和测量电路对走时差的影响。该方法可以实现岩石三阶弹性模量的高精度测定,从而为地应力测量声弹法的实现提供技术保障。更多还原

【Abstract】 Based on the acoustoelastic theory of rock,velocity variation of longitudinal and transverse ultrasonic waves propagating along the thickness direction of plate rock samples under biaxial loading condition is measured by the pulse echo method to investigate the third-order elastic modulus for rock. The test results indicate that sensors of transversal wave and longitudinal wave are set at the relative surface of the central portion of rock specimen to measure the transversal wave and longitudinal wave at the same position,which not only can weaken the biaxial loading end effect,but also overcome the influence of rock anisotropy on the measured results. Furthermore,time difference between multi-echo signals is measured by pulse-echo method to overcome the influence of couplant and measured circuit on the travel-time difference of echo signals. The pulse-echo method can implement the high-precision measurement of third-order elastic modulus for rock,which provides technical support for the measurement of in-situ crustal stresses.更多还原