| Study on the properties of marine sediments has great significance in the field of militaryand civil affairs. Employing acoustic methods to get parameters of sediments has beengradually become the prime topic in oceanographic study. This paper is mainly aimed atdeveloping the inversion of sediments parameters and the measurement of geoacousticparameters in the laboratory.The inversion in this paper is applied based on effective density fluid approximationreflection model deriving from Biot theory. The object function which depends on reflectionloss is constructed by means of the optimization design of inversion, and the niche geneticalgorithm is chose to play this inversion. Then this inversion is verified through simulationcase and measured reflection loss data respectively. From the inversion results of eachparameter, it is found that porosity, mass density of grains and sound speed have very highaccuracy, followed by mean grain size and attenuation, and the uncertainty of bulk modulusof grains is relative large.During the measurement of the geoacoustic parameters of sediments, a wide-bandfrequency measurement method which is based on pulse compression technique, is developedin this paper including the explanation of measurement principle and the simulation. Finally,the sediments sample is measured in the laboratory, and through the comparison of thewide-band frequency and single frequency measurement, this method is proved reliable. Theadvantage of this method is that the measurement efficiency is improved and the dataprocessing is reduced, while the disadvantage lies in the incredible results at the edge ofmeasure frequency range and the high standard of transducer. |
