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浅地层剖面测量是海洋工程勘察、灾害地质调查和大陆架海洋地质科学研究的重要手段,资料解译的准确程度将对地质调查和研究成果的可靠性造成直接影响.由于C-Boom型浅地层剖面仪的发射换能器与水听器是分开安置的,当调查区域的水深过浅时,将其近似为自激自收的单道地震系统会导致地层的畸变,水深越浅地层畸变率越大.根据浅地层剖面仪的基本原理,推导出了C-Boom型浅地层剖面仪地层畸变率的计算公式及地层畸变校正公式,为用C-View软件更准确地解译此类浅地层剖面资料提供了参考. 相似文献
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基于在消声水池中对参量阵型浅地层剖面仪进行的声学参数测量试验及数据的处理分析,探索性地提出了一套完整的浅地层剖面仪关键声学参数检测与评价的解决方案。方案主要包括4部分:1)检测平台构建:简述了检测平台的主要组成部分,并对消声水池的建设提出了基本的技术要求;2)声学参数测量:介绍了浅地层剖面仪的声源级、频率和脉冲长度测量的方法和操作要点;3)数据处理分析:论述了测量数据预处理的目的和方法,给出了声学参数计算的主要公式和方法;4)符合性分析:分析各声学参数实测值与标称值的符合性及偏离度。本试验发现所用的浅地层剖面仪的关键声学参数的实测值与其标称值偏离较大,即说明书给出的标称值仅是参考性数值。因此,在进行浅地层剖面仪的检测与校准工作时,应对新购仪器进行强制性首检以获取其各参数准确的初始值。 相似文献
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为准确获取深远海海洋声速资料,充分了解深水声速规律,选取了西太地区两个水深超过5000m的S1和S2站位的声速资料为研究对象,以SVP(声速剖面仪)实测资料为参考标准,通过对CTD资料利用Chen-Millero、Del-Grosso以及Wilson的3种经验公式计算的声速与SVP资料进行对比分析,得出Del-Grosso经验公式计算的声速误差最小。为进一步提高声速资料精度,对Del-Grosso公式进行修正,并利用另外3个站位数据进行验证,发现利用校正后的公式计算的声速资料精度明显提升,这为其他深远海区利用CTD或其他温盐深资料获取高精度声速资料提供参考。 相似文献
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全海洋浅地层剖面仪及其应用 总被引：1，自引：0，他引：1
全海洋浅地层剖面仪(Topographic Parametric Sonar,TOPAS)PS 018系统是目前世界上最先进的浅地层剖面仪之一。该系统是全海洋宽带非线性差频浅地层剖面仪,可对海底地层进行全方位测量,同时还兼有测量水深的功能,最大地层穿透深度为150 m,最小分辨率为0.3 m。系统多种发射信号(Ricker波、Burst波和Chirp波)的选取方便了操作者使用,从理论上实现了全海洋测量功能。从实测剖面分析,该系统是中、深水地层测量的理想测量系统。 相似文献
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海洋工程勘察中,中浅地层剖面是一种应用广泛的调查设备,其具有便携性、高效率、高主频和高分辨率的特点。实际调查中,随机噪音、多次波等问题严重降低了地层剖面资料的信噪比和分辨率,同时,现场作业对海况的依赖性很强。文中从中浅地层剖面的野外采集设备和室内资料处理方面分析,提出立体震源、多道接收系统、带通滤波、预测反褶积和相关滤波等方法。立体震源拓宽了地层剖面资料的频带,获得了更深的剖面和更高的分辨率;多道接收系统使中浅地层剖面数据由单道变为多道,有利于室内资料处理;对于目前主流的单道中浅地层剖面数据,首先要识别噪音的来源和特征,再通过增益、带通滤波、涌浪校正,预测反褶积等方法来处理,最后获取的高质量地层剖面资料一定是各种方法的综合使用和多次试验的结果。 相似文献
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海洋工程勘察中，中浅地层剖面是一种应用广泛的调查设备，其具有便携性、高效率、高主频和高分辨率的特点。实际调查中，随机噪音、多次波等问题严重降低了地层剖面资料的信噪比和分辨率，同时，现场作业对海况的依赖性很强。本文从中浅地层剖面的野外采集设备和室内资料处理方面分析，提出立体震源、多道接收系统、带通滤波、预测反褶积和相关滤波等方法。立体震源拓宽了地层剖面资料的频带，获得了更深的剖面和更高的分辨率；多道接收系统使中浅地层剖面数据由单道变为多道，有利于室内资料处理；对于目前主流的单道中浅地层剖面数据，首先要识别噪音的来源和特征，再通过增益、带通滤波、涌浪校正，预测反褶积等方法来处理，最后获取的高质量地层剖面资料一定是各种方法的综合使用和多次试验的结果。 相似文献
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Acoustic environment and physico‐mechanical properties of the shelf seabed off the pearl river mouth
Abstract The vast shallow sea off the Pearl River mouth in the northern South China Sea is an important prospecting area for offshore oil development. In recent years, the authors have investigated acoustic and geotechnical characteristics of marine sediments in this area. An intercalated layer of low sound velocity and low compressive strength has been found within the seabed, in which the median diameter of sediment grains is fine and the sound velocity is 100–200 m/s lower than that of the overlying and underlying layers. The minimum unconfined compressive strength of this layer is 0.075 kg/cm2, which is lower than that of the over‐ and underlying layers by an order of magnitude. Such an intercalation often constitutes a threat to the stability of shallow foundation soil. In case of overloading, the layer may be weakened, and seafloor sliding between different sediment layers may occur. The regional distribution of these kinds of weak intercalations of low sound velocity may be traced by a subbottom profiler and by means of sediment acoustical investigations. Correlation between the gray level of a layer on subbottom profile records and physical properties of the layer (including sound velocity and reflectivity) suggests that the layer of sufficient bearing capacity must be searched by means of sediment acoustics at least to the depth of a high‐velocity substratum of stronger reflection. 相似文献
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为厘清海底沉积层声学特性信息的水声环境保障需求,构建浅海两层海底环境参数模型,并参考Hamilton海底底质9种分类设置沉积层声速、密度、衰减系数及厚度的参考值及计算采样区间,利用Kraken简振波模型,采用控制变量的方法,研究了浅海沉积层声学特性参数对声传播损失的影响;开展了建模理论推导及数值技术分析,研究了海底沉积层声学特性参数在模型计算过程中调用过程,并从建模计算的角度对仿真计算的结果进行解释,对海底沉积层声学特性调查装备发展及调查重点参数具有一定的参考价值。 相似文献
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基于高分辨率浅剖与钻孔信息对比的金州湾海底声速的统计特征 总被引：1，自引：0，他引：1
声波在海底沉积物中的传播速度是一个重要参数，弄清海底沉积物中声速的变化规律具有极其重要的意义。以渤海金州湾海域为例，在进行畸变校正的基础上，基于高分辨率浅地层剖面与钻孔数据的对比分析，实现了全新世沉积层和基岩界面以上沉积层声速的准确反演，并采用统计学方法分析讨论了研究区内的声速特征和变化规律，结果表明，全新世沉积层平均声速的95%置信区间为1 449.60～1 655.72 m/s，平均值为1 560.34 m/s；基岩界面以上沉积层平均声速的95%置信区间为1 657.96～1 970.80 m/s，平均值为1 765.63 m/s；研究区内海底地层的声速与埋藏深度之间呈现明显的正线性相关关系，声速梯度为4.18 s?1。 相似文献
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ABSTRACT Using physical (acoustical engineering mechanics and scanning electron microscope) and other technical methods, is study makes a comprehensive analysis of the structural characteristics and engineering mechanics properties of sediments, the sediment structure, microstructure and their classification characteristics and in the light of the physical-mechanical characteristic parameters, the relations between the grain contact, grain accumulation, and porosity with the physical-mechanical characteristics of sediment, and reports the relationship between the acoustic physical parameters and the stress-strain properties of sediment. Results show that there are six structural types in the shelf seabed sediment of the northern South China Sea, among which, the mixed contact structural type sediment has a higher compressive strength and a higher sound velocity than others, and that in the shallow seabed there exists a mesoscale structure with high and low velocity layers. 相似文献
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Kraft B.J. Overeem I. Holland C.W. Pratson L.F. Syvitski J.P.M. Mayer L.A. 《Oceanic Engineering, IEEE Journal of》2006,31(2):266-283
Geoacoustic properties of the seabed have a controlling role in the propagation and reverberation of sound in shallow-water environments. Several techniques are available to quantify the important properties but are usually unable to adequately sample the region of interest. In this paper, we explore the potential for obtaining geotechnical properties from a process-based stratigraphic model. Grain-size predictions from the stratigraphic model are combined with two acoustic models to estimate sound speed with distance across the New Jersey continental shelf and with depth below the seabed. Model predictions are compared to two independent sets of data: 1) Surficial sound speeds obtained through direct measurement using in situ compressional wave probes, and 2) sound speed as a function of depth obtained through inversion of seabed reflection measurements. In water depths less than 100 m, the model predictions produce a trend of decreasing grain-size and sound speed with increasing water depth as similarly observed in the measured surficial data. In water depths between 100 and 130 m, the model predictions exhibit an increase in sound speed that was not observed in the measured surficial data. A closer comparison indicates that the grain-sizes predicted for the surficial sediments are generally too small producing sound speeds that are too slow. The predicted sound speeds also tend to be too slow for sediments 0.5-20 m below the seabed in water depths greater than 100 m. However, in water depths less than 100 m, the sound speeds between 0.5-20-m subbottom depth are generally too fast. There are several reasons for the discrepancies including the stratigraphic model was limited to two dimensions, the model was unable to simulate biologic processes responsible for the high sound-speed shell material common in the model area, and incomplete geological records necessary to accurately predict grain-size 相似文献
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对南海某海域深度100～400 m的海底浅层（约2 m埋深范围）沉积物柱状样在接近海底水压力下进行三轴应变-声学同步测量,结果表明沉积物纵波声速有两个特征:（1）从应变过程开始到结束,沉积物纵波声速不断变化;（2）平均声速随着平均静弹性模量的增加,由大变小又由小变大,存在声速最小值。这些结果与海底浅表层沉积物的物理力学性质、围压、颗粒的结合状态改变有关。此外,沉积物动弹性模量和孔隙度呈良好的负相关性,这与孔隙度增大含水量增大有关;动弹性模量是静弹性模量的10～100倍,这主要与三轴应变试验的应变数量级与声波振动产生的应变数量级的差异大有关。采用本论文实验测量的数据分别建立了双复合参数-声速和孔隙度-声速经验公式,分析结果表明双复合参数-声速公式声速预报误差约是孔隙度-声速公式的1/4,表明双复合参数-声速公式更加有效。 相似文献
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海上单道地震与浅地层剖面数据海浪改正处理研究 总被引：2，自引：1，他引：1
因受海面大风浪与涌浪等影响,海上单道地震与浅地层剖面数据反射同相轴常出现波浪状起伏,造成剖面反射层位错乱,分辨率与信噪比降低。根据海浪噪声与海底反射地层在横向上的相关性与变化频率等特性,以及综合前人的研究成果,采用陆上地震数据剩余静校正处理中的统计模型道互相关方法来实现对剖面反射同相轴的海浪改正处理;为减少强能量噪声对相关运算的影响,采用中值滤波、光滑滤波技术对反射同相轴曲线进行滤波处理,以进一步减少残留海浪的影响及相关运算改正误差。将这些方法综合运用于海上实际调查资料处理后,大风浪与涌浪影响下的波浪状反射同相轴变得连续、光滑,海底下混乱模糊的反射层位变得清晰、连续,剖面信噪比与分辨率得到了极大的提高。 相似文献
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Physical Properties of Sediments on the Northern Continental Shelf of the South China Sea 总被引：1，自引：0，他引：1
Using physical (acoustical engineering mechanics and scanning electron microscope) and other technical methods, is study makes a comprehensive analysis of the structural characteristics and engineering mechanics properties of sediments, the sediment structure, microstructure and their classification characteristics and in the light of the physical-mechanical characteristic parameters, the relations between the grain contact, grain accumulation, and porosity with the physical-mechanical characteristics of sediment, and reports the relationship between the acoustic physical parameters and the stress-strain properties of sediment. Results show that there are six structural types in the shelf seabed sediment of the northern South China Sea, among which, the mixed contact structural type sediment has a higher compressive strength and a higher sound velocity than others, and that in the shallow seabed there exists a mesoscale structure with high and low velocity layers. 相似文献
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海底浅表层（小于1 m）沉积物的物理性质,如粒度、孔隙度、密度等是海洋沉积学研究和海洋工程地质分析的重要内容,目前主要基于有限的海底取样或原位测试获取这些沉积物的物理性质。浅地层剖面是基于声学信号（频率几千赫兹）在沉积物中的传播得到可反映沉积地层结构的数据,其中的一些声学参数,如海底反射系数、波阻抗等与沉积物物理性质密切相关。如何充分而有效地利用浅地层剖面资料,反演得到剖面覆盖区海底浅表层沉积物的物理性质参数,极具科学意义和应用价值,且基于声学属性反演沉积物物理性质是当前研究的热点。为此,本文基于渤海LD16-3CEPA至LD10-1PAPD路由段的浅地层剖面数据和海底表层沉积物的实测物理参数,利用Biot-Stoll模型建立研究区海底反射系数和沉积物物理性质之间的关系,并基于浅地层剖面数据计算得到的海底反射系数,反演了研究区海底浅表层沉积物的孔隙度、密度、平均粒径等物理性质参数。其中反演的孔隙度、密度、平均粒径与实测孔隙度、密度、平均粒径基本相符,偏差度基本都在20%的偏差范围内,表明该反演方法在该区的应用是可行的。 相似文献