A multi-frequency ultrasonic amplitude attenuation method for identifying damage of rockOA

High-temperature damage in rocks significantly affects ultrasonic amplitude attenuation.Inverting rock damage through amplitude attenuation offers a rapid,non-destructive,and convenient detection method.However,the single-frequency ultrasonic testing method,due to its single amplitude attenuation parameter and relatively large experimental error,is difficult to fully reflect the material''s characteristics.Ultrasonic flaw detection methods based on multi-frequency amplitude attenuation are relatively scarce.To address this,the study proposes a multifrequency ultrasonic amplitude attenuation detection method,eliminating single-frequency measurement errors and accurately characterizing the attenuation behavior of thermally damaged rocks.Experimental results show that after high-temperature treatment,P-wave amplitude attenuation increases progressively with frequency(by 50%),whereas S-wave attenuation first decreases and then rises.A correlation model between amplitude attenuation and damage variables was established,confirming that P-wave attenuation effectively quantifies rock damage.The study initially explored the interaction mechanism between multi-frequency ultrasonic and fractures:low-frequency waves exhibit increased attenuation due to boundary reflections,while high-frequency waves show enhanced attenuation as diffraction effects weaken.These findings bridge a critical gap in multifrequency amplitude attenuation research and provide a scientific basis for identifying high-temperature damage in rocks.