Abstract: Borehole shear wave velocity measurement and thickness of overburden soil estimation for buildings in plain regions are based on the relative depth to the surface elevation. For the site preparation of construction projects in mountainous area, the foundations for a lot of buildings would experience cut or fill conditions. Therefore, the seismic site class might be changed, site seismic performance would be therefore different, so that the site seismic class might also be different at the project site. In this paper, based on datum at each building after the site preparation, and the proposed ground surface elevations adjacent to the proposed buildings, the average overburden soil thickness is re-estimated so that that the site seismic class at each building could be estimated. This paper provides a new method for the site seismic classification for building sites with significant elevation differences in the mountainous areas.

Key words: elevation difference, construction site class, overburden soil layer thickness, borehole shear wave velocity measurement, site classification method