ABSTRACT
Seismic refraction surveys have been widely used for geological investigation of tunnels in Japan. The relationship between seismic velocity and rock classification has been well established. Tunnel linings are designed based on the rock classification. The ordinary seismic refraction survey is suitable to geology in which seismic velocity increases with depth. However, it has disadvantages for investigating areas with complicated geology and weathering patterns. An ordinary seismic refraction analysis and a seismic geotomography analysis are carried out for the same proposed tunnel. The results of both are compared with horizontal geotechnical drilling results and tunnel excavation records, which were obtained in the later stage. The seismic geotomography analysis results agreed with the actual rock conditions better than the ordinary seismic analysis results.
