Research Of The In Situ Acoustic Measurement Technique Of Marine Sediments

The in situ acoustic measurement technique of marine sediments is the advanced technique in measuring the accurate acoustic properties. Supported by the national"863"plan"the in situ acoustic measurement technique of marine sediments", the paper introduced a new in situ acoustic measuring method and developed the in situ measurement system of marine sediments. The paper includes the acoustic and physical properties of marine sediments, the design and developing of the in situ acoustic measurement system, the system adjustment, the experiment in laboratory, sea beach and on the sea.The in situ acoustic measurement system of marine sediment is different from the prevenient techniques. It can measure the acoustic properties not just in manner of the station after station but in manner of dragging. The paper introduced the method of computing the velocity and attenuation coefficient. The paper read the first arrival time of acoustic wave based on the application of modulus maxima. We get the accurate distance between the two receiving transducers by adjusting the system in sea water.The velocity and attenuation coefficient were measured in the under water acoustic laboratory. We also measured the velocity on three sea beach areas where the sediments had the different mean grain size. The measurement system was tested on the Qingdao offshore area. We got the velocity of nine stations and sampled the sediments. We analyzed the sediments type and mean grain size, preliminary studied the correlation between the acoustic and physical properties of sediments. In summary, it is observed that the measurement system work stable, and can give the in situ acoustic velocity and attenuation coefficient of marine sediment.