Application of the surface wave method to various geotechnical structures of finite boundaries

Abstract

The shear wave velocity (Vs) profile is one of the essentially required characteristics of the site for static deformation analyses as well as for earthquake ground response analyses. Various seismic surface wave methods are widely used for site characterization. Recently there has been growing interest in Vs subsurface imaging especially using surface wave methods. Each method has its own characteristics in field testing and data analysis. Therefore, it is very important to recognize the reliability and applicability of each seismic test used in the project. In practice, their characteristics and limits of their application have not been considered properly, leading to inaccuracy and incongruent results in the projects. Generally, surface wave methods have been applied to ground and soil structure system with fundamental assumption that the evaluated system consists of a set of homogeneous layers of constant thickness. In reality, however, such ideal conditions cannot exist. One of problems is horizontal variation of underground stiffness. Many researchers studied on the effect of non-homogeneity and evaluation of 2 dimensional Vs imaging. However, field verification studies were not satisfactory as it was difficult to know reliable reference Vs values of experimental site for comparison purposes. Moreover, researchers have focused on verification of its reliability in constructing a two-dimensional Vs image. But it was nearly impossible to know the exact two dimensional reference values of the experimental site. To verify the applicability of surface wave methods, reference information of the site is required to be known in the field. In this study large scale model testing site was constructed to verify the reliability of the surface wave methods more definitely, especially HWAW method. The approximate size of the model testing site is $16m\times26m\times8.5m (W\timesL\timesH)$ and the testing site consisted of four-layered model and each layer had differe...