168 / 2024-03-08 17:10:59

Seismic Performance of Concrete Tunnel-Sand-Pile Interaction (CTSPI) by Shake Table Test

Experimental Investigations,Interactive Displacements and Moments,Mohr-Coulomb Model,Numerical Analysis,Square Root Sum of Squares (SRSS)

This research presents the square root sum of squares (SRSS) response of displacements and tunnel moments under the Kobe and Loma Prieta seismic excitations with a peak ground acceleration of 0.05g for various dry relative densities of the 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 (CTSPI) model. The vertical 40 Kg load was applied on each pile cap along with the seismic excitations. Experimental results are compared to the previous numerical study conducted by using field data for understanding the variations of results. In the case of vertical sand displacement, the ratio between the previous field data used numerical study and the present study is found to be 0.96. Also, experimental results are compared to 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 agreement with the reference of previously published work. According to the shake table test results, the lateral displacement of tunnel is more than the vertical displacements of tunnel and sand because of the transverse directional seismic excitation on the tunnel body. The minimum difference between lateral and vertical displacements of tunnel is found to be 31% for the relative density of 27% under the Loma Prieta earthquake. However, this research may be enhanced in the future to consider various peak ground accelerations, tunnel-pile clearance, and geometric properties.