基于海底表层沉积物声速特征的南海地声模型
A geoacoustic model based on sound speed characteristic of seafloor surface sediments of the South China Sea
-
摘要: 在由垂直声速梯度建立的地声模型基础上,通过引入沉积物与海水声速比和沉积物压缩波与切变波声速比两个表征沉积物声学特征参数得到更全面和有实际指导意义的地声模型。在沉积物声波传播FCMCM模型基础上,基于热作用和重力作用下沉积物两相介质的应力应变分析,建立TFCMCM和DFCFCM模型,运用模型校正表层沉积物声速特征来计算和解释地声模型。根据海底表层沉积物存在低声速和高声速两种类型,结合沉积物沿纵深孔隙度不变和变化两种类型,得到南海海底沉积物的两类四种典型地声模型:低声速孔隙度不变型、低声速孔隙度减小型、高声速不变型和高声速孔隙度减小型。运用这四种典型地声模型的组合解释了卢博提出的南海三种典型声速结构。认知声速结构将为南海声学探测海底、划分海底区域提供模型支持。Abstract: The sound speed ratio R1 of sediment to seawater and the sound speed ratio R2 of compressional wave to shear wave are added up to the vertical gradient of sound speed geoacoustic model (GM) so as to achieve a more comprehensive and instructional GM in practice.Considering stress-strain relations of two-phase medium of sediment under the effect of heat and gravity,TFCMCM and DFCMCM models are established on the basis of Men-Chen model by introducing a freedom factor and considering coupled-frame elastic modular (FCMCM).Both models are used to adjust the seafloor surface sediment sound speed characteristic into the in-situ state,calculate and interpret the GMs.According to analysis of the existence of high-speed and low-speed types in seafloor surface sediments and the two kinds of porosity-depth states of constant and descent beneath the seafloor sediment (PDC and PDD),four representative basic geoacoustic models of sediments in the South China Sea can be expressed as low-speed PDC,low-speed and porosity-PDD,high-speed PDC and high-speed PDD.With the usage of combination of the four basic models,the Lu Bo and Liang Yuanbo’s three sound-speed structures of the South China Sea can be rationally explained as an example of the actual sedimentary acoustic state.The understanding of basic geoacousic models will benefit the seafloor inspection and classification of sea bottom regions with acoustic methods in the South China Sea.
-
Key words:
- sound speed /
- gradient /
- the South China Sea /
- sediments /
- geoacoustic model
-
粱元博,卢博.海底的物理——地声结构[J].南海海洋科技,1985,6:49-53. 卢博,梁元博.中国东南沿海海洋沉积物物理参数与声速的统计相关[J].中国科学:B,1994,24(5):556-560. HAMILTON E L.Geoacoustic modeling of the sea floor[J].Journal of the Acoustical Society of America,1980,68:1313-1340. 邹大鹏,吴百海,卢博,等.海底沉积物声速实验测量结果校正的研究[J].热带海洋学报,2008,27(1):27-31. 梁元博,卢博.某海区陆架低声速底质的声学物理参数[J].热带海洋,1983,2(2):1-9. LIANG Y B,LU B,WONG How Kin.Acoustic discrimination of seafloor Properties //Oceanology of China Seas,Netherlands:Kluwer Academic Publisfers,1994:547-556. ZOU D P,WU B H,LU B.Study on properties of compressional wave speed of water saturated porous medium //Proceedings of ICFP2009,Vol.1.Beijing:World Publishing Corporation,2009:888-891. 邹大鹏,吴百海,卢博,等.温度对水饱和孔隙介质压缩波速度的影响[J].声学技术,2008,27(4):492-496. HAMILT0N E L.Prediction of in-situ acoustic and elastic properties of marine sediments[J].Geophysics,1971,36 (2): 366-377. 门福录.波在饱水孔隙弹性介质中的传播[J].地球物理学报,1965,14(2):107-114. 门福录.波在饱含流体的孔隙介质中的传播问题[J].地球物理学报,1981,24(1): 65-76. 陈龙珠,吴世明,曾国熙.弹性波在饱和土层中的传播[J].力学学报,1987,19(3):276-283. 吴世明,陈龙珠.饱和土中弹性波的传播波速[J].应用数学和力学学报,1989,10(7):605-612. URICK R J.海洋中的声传播[M].陈泽卿译.北京:海洋出版社,1990. 卢博,李赶先,黄韶健.南沙海域浅层沉积物声速与物理参数的相关关系 //南沙海域声光场研究论文集.北京:海洋出版社,1996:9-22. OGUSHWITZ P R.Applicability of the Biot theory:Ⅲ.Wave speeds versus depth in marine sediments [J].The Journal of the Acoustical Society of America,1985,77(2):453-464. HAMILTON E L.Variations of density and porosity with depth in deep-sea sediments [J].Journal of Sedimentary Petrology,1976,46:280-300. SINCLAIR B,DENZIL T S.Deep-sea sediment compression curves:some controlling factors,spurious overconsolidation,predictions,and geophysical reproduction [J].Marine Georesources and Geotechnology,1999,17:65-81. HAMILTON E L.Sound velocity gradient in marine sediments [J].The Journal of the Acoustical Society of America,1979,65:909-922. -
点击查看大图
计量
- 文章访问数: 1459
- HTML全文浏览量: 5
- PDF下载量: 1244
- 被引次数: 0
下载:
