Evaluation of Mathematical Relationships of Shear Wave Velocity and Standard Penetration Test Results with Bayesian Statistics Approach

Shear wave velocity is one of the most important geophysical parameters in which the seismic response of the sites is expressed. This seismic parameter gives valuable information about the project site, but since geophysical tests are usually expensive and time consuming, the use of indirect methods to reduce costs is increasing. Much research has been done in different regions of the world, in most of them have used both simple power equations and multiple power equations to derive equations. However, in this paper, a comprehensive study is conducted to evaluate the effects of standard penetration number and depth on shear wave velocity estimation as one of the most important soil dynamic parameters with Bayesian statistics approach. In summary, data from 28 boreholes drilled in three cities of Hormozgan province were collected. The collected data were subdivided into four main categories of all soils: clay soils, silty soils, sandy and gravel soils. In this way, the researchers identified 8 variables and 13 functions with the help of Bayesian statistics to determine the mathematical functions with greater reliability, taking into account standard penetration number, depths or a combination of both. The results of this analysis showed that the standard penetration number parameter alone for all soils and classifications as well as simple and multiple power equations are not the best parameter and equations in predicting shear wave velocity, respectively. Other results can be pointed out that soil clustering is not always the most effective factor in estimating shear wave velocity. Finally, it is suggested that if the correlation equation is defined on the basis of standard penetration number with higher confidence percentage, the equation will be extracted by intervals from standard penetration number. In addition, despite the results, it should be noted that these equations have been developed for a specific site and these results should be used with regard to site specific arrangements with other geotechnical conditions.