南海海底粉质黏土沉积物声速和衰减的全浸式测量

Full immersion measurement on the sound speed and attenuation of the abyssal silty-clay sediment in South China Sea

提出了一种宽带声速和声衰减测量方法,该方法利用全浸式传感器测量技术(FITM)在实验室环境下对超细沉积物(平均粒径为5.27μm,孔隙率为79%)的声速和声衰减进行了测量。为确定该实验室测量方法的可靠性,将该声速与声衰减关系与Kramer-Kronig关系进行了比较。同时,Hamilton经典曲线表明,该实验室测量结果符合声速与孔隙度关系,且声衰减在Hamilton曲线置信区间内。测量数据满足有效密度流体模型和颗粒剪切模型的声速和衰减预测曲线,进一步证明了实验室测量方法的准确性和有效性。

By using full-immersion transducer measurement(FITM),a broadband sound speed and attenuation measurement method is presented,which provides a way to obtain the sound speed and attenuation of ultrafine sediments(average particle size of 5.27μm and porosity of 79%)in laboratory.The dependence between sound speed and attenuation was compared with Kramers-Kronig relation for confirming the reliability of the in-lab measurement.Meanwhile,Hamilton classic curves indicate that the in-lab measurement results meet the speed-porosity relation,and the attenuation from the in-lab method is within the confidence interval of Hamilton curves.The sound speed and attenuation prediction curves of the effective density fluid model and the grain-shearing model are satisfied which also proves the accuracy and availability of the in-lab measurement method.