| 海底沉积物的基本地声结构与地声模型 |
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| 引用本文： | 邹大鹏,伍智林,孙晗,刘伟,纪轩荣,肖体兵.海底沉积物的基本地声结构与地声模型[J].海洋学报,2022,44(9):145-155. |
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| 作者姓名： | 邹大鹏 伍智林 孙晗 刘伟 纪轩荣 肖体兵 |
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| 作者单位： | 1.广东工业大学 机电工程学院，广东 广州 510006 |
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| 基金项目： | 国家自然科学基金（41776043，41976180）；声场声信息国家重点实验室开放基金（SKLA202105）。 |
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| 摘 要： | 为准确建立海底地声模型，本文探讨地声模型的基本组成和基本结构。通过样品实验室测量，分析南海海底表层沉积物的密度、孔隙度与声速随着埋深变化的关系，得出海底实际存在的低声速表面–声速缓慢变化类型、低声速表面–声速增大类型、高声速表面–声速缓慢变化类型和高声速表面–声速增大类型4种典型地声结构；对比钻探测量，分析黄海海底沉积物的密度、孔隙度与声速随埋深变化关系，得出海底地声模型分层特征与地声结构组合特征。研究表明，地声模型可以归结为4种基本地声结构的组合，通过与底层海水声速、同层内声速剖面以及与上层海底沉积物下表面声速的比较，可以建立各种海底地声模型；基于实验室测量法建立的地声模型可以作为参考地声模型，但需要考虑实际海底温度和压力梯度以及海底沉积物的频散特性等，借助于声速比校正法和频散性理论模型进行计算及修正。
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| 关 键 词： | 地声模型 声速剖面 海底沉积物 声速 频散 |
| 收稿时间： | 2021-10-20 |
Basic geoacoustic structure and geoacoustic model for seafloor sediments |
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| Institution: | 1.School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006, China2.State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China3.State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment, Guangdong University of Technology, Guangzhou 510006, China |
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| Abstract: | To accurately establish a geoacoustic model for seafloor sediments, the elemental composition and structure of the geoacoustic model are explored in this paper. Based on the laboratory measurements of seafloor sediment samples, the buried depth relationship between density, porosity, and sound velocity of seafloor surface sediments in the South China Sea is analyzed. Four typical seafloor geoacoustic structures are obtained: low sound velocity surface-sound velocity slow change type, low sound velocity surface-sound velocity increase type, high sound velocity surface-sound velocity slow change type, and high sound velocity surface-sound velocity increase type. By comparing the drilling survey and analyzing the buried depth relationship between density, porosity, and sound velocity of seafloor sediments in the Yellow Sea, the actual layered characteristics and the combination characteristics of the geoacoustic structure are obtained. It shows that the geoacoustic model can be attributed to a combination of four basic geoacoustic structures. Various actual seafloor geoacoustic models can be derived from the comparisons between the acoustic sound speed of the bottom seawater, the sound velocity profile of seafloor sediments in the same layer, and the bottom sound velocity of the upper sediment. The geoacoustic model based on the laboratory measurement analysis of seafloor sediment samples can be used as a reference geoacoustic model. However, it should be modified with the sound velocity ratio correction method and theoretical calculation method of dispersion characteristics with the consideration of the actual seafloor temperature gradient, pressure gradient, and dispersion characteristics of seafloor sediment. |
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