NUMERICAL STUDY OF STRUCTURE-SOIL-GROUP PILE FOUNDATIONS USING AN EFFECTIVE STRESS BASED LIQUEFACTION ANALYSIS METHOD

摘要

Seismic behavior of pile foundations is widely discussed by many researchers in order to do research of safer and more economic designs for the infrastructure during earthquakes. In usual, civil structures are constructed on a foundation with group piles installed rather than a single pile, moreover, the interaction among soils and piles depends on the liquefaction of surrounding ground of the infrastructure. The authors carried out a of liquefaction analysis using an effective stress based liquefaction analysis method on a real structure-pile foundation-ground, in which a five story building in Kobe area was shocked to damage in 1995 Hyogoken-Nambu Earthquake. In the present numerical simulations, we adopted a numerical code LIQCA3D which was developed by some of the authors. From the numerical simulations, it was found that the acceleration responses, velocity responses and displacement responses of the ground agree well with the observations, and the distance of the piles installed in the footing influences the built-up of the excess pore water pressure and the damage on both pile heads and low segments of the pile at the boundary takes place before the complete of liquefaction during these major earthquakes.