Study On Seabed Sediments Ultrasound Signals In Temperature Influence

Seabed sediments is a complex porous media, granular solid mineral and. biological debris, as long deposition and accumulation of a porous skeleton, the skeleton in the pore water is filling the pores of a typical elastic medium. Research on marine sediments of marine resources development, submarine construction, Seabed mapping, marine disaster forecasting, submarine history, shipping, such as national defense.The inherent characteristics of marine sediment can be used physical properties, mechanical properties, to describe the nature of acoustics, and the inherent characteristics of a normally due to the impact of external environmental factors, including, temperature, pressure, salinity changes. At present the main marine sediment to detect ultrasound measurement-based, access compression wave velocity, shear-wave velocity, acoustic impedance, sound attenuation. In this paper, use of ultrasound spectral analysis method, access to ultrasound signals in the spectrum to study the characteristics of the sediment-frequency characteristics, for the speed of sound to the traditional, sound attenuation, and other parameters describing the physical properties of the sediment acoustic signal to provide measurements of different perspectives.This paper samples from the Chinese Academy of Sciences, the South China Sea Institute of Marine Research in April 2007 expedition remaining seabed sediment sampling. Elements include:The production of samples, test equipment calibration ultrasound transducer frequency, testing transducer its own temperature-frequency characteristics. Although the temperature reached the transducer have a certain system error, but does not affect the sediment ultrasound tests conclusions.Thermal-speed access to the sediment characteristics: A linear speed of sound and temperature-related and the probability of plus or minus related, sediment or cooling changes do not affect the speed of sound.Through the sediment movements that temperature experiment: to increase the frequency with the temperature increased frequency of the direction of drift; frequency components of the amplitude of the spectrum are with the temperature increase and decrease the frequency and amplitude of bandwidth was negatively correlated, but with the temperature has not yet Found a clear correlation between the sample has the same temperature change process with the amplitude of the corresponding size of close-knit; frequency temperature characteristics and sediment particle size analysis of data is not closely linked. Above phenomenon, the temperature change the internal structure of the sediments, seepage state arising from changes in the frequency drift; warming caused by sediment in the energy signal attenuation; plus or minus temperature gradient changes will have on many occasions the frequency of temperature change, and so on.Tempreture made the frequency of regression analysis, the basic quadratic polynomial fitting can be used to verify the above conclusions, and noted that under the second factor of plus or minus all divided into two types.