ESTIMATING GEOLOGICAL STRUCTURES USING SEISMIC REFLECTION PROFILING FROM SHIELD TUNNEL

Abstract

We propose a new approach using the seismic reflection profiling for estimating geological structures around shield tunnels. In the study including field tests, we found that an elastic wave (S wave) generated inside a shield tunnel transmits to the ground around the tunnel through its concrete segments and reflects at geological layer boundaries. In the proposed approach, the reflected waves are detected by geophones set inside the tunnel and geological structures above and below the tunnel are estimated through the date processing of the seismic reflection profiling. This approach was experimentally applied for an existing shield tunnel and the estimated seismic zones are consistent with the geological data observed by the boring survey.