Ultrasonic test and sensitivity analysis of rock viscosity coefficient

Based on the amplitude attenuation law of ultrasonic waves in the propagation process of Kelvin-Vigot viscoelastic body, the theoretical calculation formula of viscosity coefficient for rock is derived.Through the ultrasonic test of indoor rock samples, the viscosity coefficient at different transmitted wave frequency is obtained.Correlation analysis is carried out to analyze the correlation between rock viscosity coefficient and density, wave velocity and elastic modulus.The results show that the viscous coefficient of rock is negatively exponential to the frequency of the incident wave.The viscosity coefficient of rock is most sensitive to the change of elastic modulus and least sensitive to the change of longitudinal wave velocity.The modulus of elasticity of the rock can be used to characterize the viscosity coefficient.A unified fitting formula for the viscosity coefficient of rock with the frequency of the incident wave is established.The fitting parameter C₁ is most sensitive to the changes in elastic modulus and the fitting parameter C₂ is most sensitive to the changes in the ratio of P-wave to S-wave.The research results can provide reference for rock mechanics parameter testing and rock dynamics research.