摘要:
采用压电陶瓷弯曲元法和共振柱试验的方法对采自我国海域的一些典型海底浅表层沉积物样品进行了剪切波速测试,获得首批可信数据.两种方法所测得的剪切波速数据具有很好的一致性,且在数赫兹至数十千赫兹频段范围内剪切波速不具明显弥散性.剪切波速与沉积物类型关系密切,不同海区和不同类型海底沉积物的剪切波速有明显差异.近海较细颗粒沉积物粉砂的剪切波速在100m/s左右,细颗粒沉积物的剪切波速在100m/s以下;陆架较粗颗粒沉积物的剪切波速最大,超过100m/s;深海、半深海细颗粒沉积物的剪切波速最低,小于50m/s.剪切波速与含水量、密度、孔隙度、塑限和液限等沉积物物理参数之间具很好的相关性,反映了剪切波速和物理性质之间的密切关系.剪切波速与压缩波速呈正相关性,但在不同的波速范围剪切波速随压缩波速的变化有很大不同.
Abstract:
Both piezoelectric ceramic bender element and resonant columntest technologies were used to measure effectively the shear wave velocity of seabed sediments from the East China Sea and the South China Sea in laboratory.Shear wave velocity data measured by these two methods appeared to be good consistency and no obvious frequency dispersion was found from a few hertzs to tens of kilohertzs.The shear wave velocity changed greatly in different physiographic areas and different sediment types.According to measurement data, the shear wave velocity of inshore silts is about 100 m/s and finer sediments show less than 100 m/s velocity.Coarse sediments on continental shelves are characterized by maximum shear wave velocity values, all more than 100 m/s, and fine deep-sea sediments have minimum shear wave velocity values, generally less than 50 m/s.The shear wave velocity shares a good correlation with physical properties of sediment,such as water content, density, porosity,plastic limit and liquidlimit of sediment,which reflects a strong relationship between them.The shear wave velocity also shows a positive correlation with the compressional wave velocity, but the ratio of shear wave velocity to compressional wave velocity changes obviously with the compressional wave velocity valuerange.
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