SHAKING TABLE TESTS ON SEISMIC DEFORMATION OF GRAVITY QUAY WALLS

抄録

Seismic damage to gravity quay walls in Port Island and other reclaimed islands during the Hyogoken-Nambu earthquake in 1995 consisted of the tremendous lateral displacement of caisson boxes. The field investigation immediately after the earthquake found that there was no sand boiling in the vicinity of damaged quay walls. This finding was in contrast with the fact that a large amount of sand was boiled in most other parts of the island. It was disputable, therefore, whether or not any role was played by subsoil liquefaction in the damage of quay walls. Shaking table tests were carried out in the present study in order to understand the mechanism of the wall displacement. The test results indicate that the significant deformation of walls was a consequence of the combined effects of shaking and the development of pore water pressure in sand underlying the wall. The wall displacement increased as the intensity of shaking became greater and the underlying sand was made looser. The effects of shaking frequency were important. The stress-strain and stress-path behaviors of the foundation sand were reproduced by using the experimentally recorded time histories of acceleration and pore water pressure.