Improvement effects of two and three dimensional geosynthetics used in liquefaction countermeasures

Abstract

This study focuses on accumulation of basic data on deformation and energy absorbing characteristics of geosynthetics (recycled tire chips and geogrid), which are used as liquefaction prevention materials for shallow foundations. Because tire chips have high compressibility, decrease of bearing capacity and excessive differential settlement of the foundation ground may arise. A new reinforcement method, using gravel mixed tire chips layer and layers of geogrid, was proposed to compensate for the inadequate bearing capacity and suppress differential settlement. In this study, the deformation and energy absorbing characteristics of tire chips and gravel mixed tire chips were made clear by performing direct shear test under dynamic loading using a large scale shearing device. Based on the results, it was found that the vibration-absorbing energy of tire chips decreases as the gravel fraction increases. Considering the pros and cons, we could arrive at the conclusion that the sample with 50% gravel mixture was the most effective. It was also confirmed that the rigidity of gravel mixed tire chips was improved through reinforcement by geogrid.