渤海海域黏性土剪切波速与抗剪强度统计关系的初步研究

A Preliminary Study on Statistical Relationship between Shear Wave Velocity and Shear Strength of Clayey Soil in Bohai Sea Area

剪切波速与地基土的抗剪强度、剪切模量和卓越周期等参数密切相关,是地震安全性评价中判定场地类别的一个主要指标和参数。鉴于海域工程中剪切波速往往难以直接由原位测得,而室内实验结果又常常与野外现场物探测试值存在较大差异,因此,如何通过其他途径有效获取满足工程需要的剪切波速参数,在海域工程的地震安全性评价等方面具有迫切的实用需求。为此,本文通过对渤海海域数十个石油平台项目中一系列饱和黏性土样品的剪切波速与抗剪强度实验数据的统计分析,尝试采用多种可能的函数来拟合确定二者之间的经验关系。结果表明:对于渤海海域,黏性土剪切波速Vs与抗剪强度Su之间的最佳统计经验关系为幂函数Vs=53.751Su 0.376。此关系可为渤海海域工程中通过不排水抗剪强度估算剪切波速提供一种简便可行的实用性方法。

As a key index and parameter to determine the site type in seismic safety evaluation for marine engineering,shear wave velocity is closely related to the strength,shear modulus and predominant period of site foundation soil.However,the shear wave velocities are usually difficult to be directly obtained in situ test,and the test results from laboratory are generally much different from their actual values,it is important to obtain the shear wave velocity parameters through other indirect means for the seismic safety evaluation of marine engineering.In this paper,based on the statistic analysis of the laboratory test results of the shear wave velocity and shear strength of a series of the saturated clayey soil samples from dozens of oil platform projects in Bohai Sea area,we conducted a variety of possible function fittings to determine the empirical relationship between the shear wave velocity Vs and the shear strength Su.The result shows that the power function Vs=53.751Su 0.376 represents the best statistical empirical relation among the different fitting curves.The relation function we obtain can provide a simple and feasible method for estimating shear wave velocity through undrained shear strength in marine engineering in Bohai Sea area.