The experimental observation of the rock orthorhombic anisotropy
岩石正交各向异性的实验观测

Diverse factors can contribute to anisotropy of rock velocity.Furthermore,orthotropy occurs with the perpendicular distribution of such factors.Through S-wave polarization scanning mode of ultrasonic impulse testing,rock samples with three different properties are measured to evaluate the variation of S-wave velocity in three perpendicular coordinates.By analyzing S-wave splitting of three directions and polarization of the maximum or minimum speed S-wave amplitudes,we think that the velocity orthotropy and fracture orientation observed in the grain sandstones and crack marble samples can be estimated in terms of the polarization and velocity of S-wave.Also,perpendicularity characteristics on the two types of rocks can attribute to the bedding and structure of rocks(directional grains or crystallize).Lab scale ultrasonic testing can obtain the structural direction of orthotropy.