Seismic performance of concrete tunnel–sand–pile interaction by the shake table test

Abstract This research presents the square root sum of squares response of displacements and tunnel moments under the Kobe and Loma Prieta seismic excitations with a peak ground acceleration of 0.05 g for various dry relative densities of local sand in Bangladesh. For this reason, a one‐dimensional gravitational shake table test was performed after calibration to determine the seismic performance of the concrete tunnel–sand–pile interaction model. A vertical 40 kg load was applied on each pile cap along with the seismic excitations. The experimental results obtained were compared with the previous numerical study conducted by using field data so as to better interpret the variations of results. In the case of vertical sand displacement, the ratio between the previous field data obtained through numerical study and the present study is found to be 0.96. Moreover, the experimental results were compared with the 3D full‐scale numerical analysis results of Plaxis considering the Mohr–Coulomb constitutive model of sand. Variations of experimental and numerical results show a satisfactory level of alignment with the previously published work. According to the shake table test results, the lateral displacement of the tunnel is greater than the vertical displacement because of the transverse directional seismic excitation on the tunnel body. The minimum difference between lateral and vertical displacements of the tunnel is found to be 31% for a relative density of 27% under the Loma Prieta earthquake. However, this research may be advanced in the future by considering various peak ground accelerations, tunnel–pile clearance, and geometric properties.