REDUCTION EFFECTS OF LIQUEFACTION DAMAGE USING SMALL SCALE FLOATING GRID-TYPE IMPROVEMENT FOR EXISTING SMALL SCALE STRUCTURE

Abstract

Earthquake resistance of important structure have benn promoted based on the lessons learned from the big Earthquake in Japan. However, liquefaction still causes serious damages to many detached houses in the world. Also, most soil improvement methods apply to original ground without structure, and countermeasure against liquefaction for existing small structure has not been sufficiently investigated. Therefore, we investigated reduction effects of liquefaction damage using small grid-type improvement as countermeasure against liquefaction for existing small structure. To this end, 2D model tests under 1g condition and non-linear FEM analyses have been carried out. From the model tests results, it was found that if the interval of improved wall is within 1.2 times of the base width, some degree of counter measure effect agaisnrt subsidence due to liquefaction can be obtained with a small grid-type improvement where the improvement depth is about twice the base width. The numerical simulation has shown a similar result as found in the observations.