Three-dimensional site characterization with borehole data - A case study of Suzhou area

Due to the inherent spatial variation of the site information and the limited number of boreholes which could be afforded in a specified project, the geotechnical and geological information at a site could not be fully characterized, which imposes a significant challenge to the analysis, design and construction of the geotechnical system of concern. Indeed, the issue of site characterization has long puzzled engineers. This paper presents a three-dimensional site characterization in the urban area of Suzhou where plenty of borehole explorations have been undertaken. With the borehole database established, the relationship between the shear-wave velocity and the depth is analyzed, this relationship can be captured by regression-based models; and then, a sequence extrapolation method that is based upon the linear relationship between the time average shear-wave velocities is developed for the prediction of the shear-wave velocity along the depth. Next, a three-dimensional characterization and visualization of the stratigraphic model in the urban area of Suzhou are presented. The characterization of the stratigraphic model, in this paper, is realized through the characterization of the elevations of the interfaces between adjacent strata in the sequence stratigraphic structure. The sequence stratigraphic structure is derived with a method that is based upon the one-by-one comparison and updating of the borehole data; and then, the best unbiased estimator of the elevations of the interfaces between adjacent strata at the concerned site is predicted with the Kriging-based interpolation method. With the aid of ArcGIS Engine, a three-dimensional visualization of the characterized stratigraphic model is made possible.