Correlation Between Seismic Damages of Tawarayama Tunnel and Ground Deformation Under the 2016 Kumamoto Earthquake

The spatial correlation of the ground deformation at Mt. Tawarayama in Kumamoto City in Japan with the seismic damages of Tawarayama tunnel was developed to explore whether the seismic damages of underground structures are related to the ground deformation. A pair of digital elevation model data sets were captured from the high-density airborne light detection and ranging data before and after the 2016 Kumamoto earthquake. A new variant of iteratively closest point (ICP) algorithm named combination and classification ICP was introduced to detect the three-dimensional ground deformation field. The seismic damages of Tawarayama tunnel caused by the earthquake were studied via site investigation. The results indicated that the strong ground deformation can reflect the seismic performance of the tunnel to some extent. Furthermore, the results of the ground deformation direction validated the assumption of seismic wave propagation along the tunnel. It gives a clear explanation for the mechanism of the seismic damages under the earthquake force, especially lining cracks, pavement damage, and construction joint damage.