Geotechnical Engineering Laboratory: Hayakawa Tsubasa Title: Time dependence on shear modulus and liquefaction resistance of glass beads Supervisor: Hirofumi Toyota Efforts to recycling for industrial waste and specially controlled waste have become active because awareness of establishing a recycling-oriented society has been increasing in recent years. For instance, according to some news, waste glass was broken into pieces and grinded to make an artificial sandy using this processed glasses. However, waste glass bottles of about 600,000 tons per year are discarded as landfill disposal without recycling use. In that situation, it is important to understand the geotechnical properties of those processed glasses in order to use the waste glasses extensively in civil engineering. In this study, the cyclic undrained triaxial test to examine liquefaction properties, local small strain and bender elements tests to examine small deformation properties, and static penetration test to examine static penetration resistance were conducted using long-term consolidated glass beads specimens. Time dependence effects of the glass beads specimen were investigated comparing with the results obtained from Toyoura sand specimen. This study has revealed the following findings. 1. Liquefaction resistance and shear modulus @a. Glass beads have greater those values than Toyoura sand have. The reason might be that the initial void ratio of the glass beads becomes small because of its spherical shape. @b. Although those values of the glass beads exhibited an increasing tend until about one week during long-term consolidation, this trend of Toyoura sand was unapparent. This result indicates the generation of particle hardening (cementation) in the glass beads. 2. Drained shear strength and penetration resistance @a. Glass beads have smaller those values than Toyoura sand have. The reason might be that the glass beads slip easily between particles because of its spherical shape. @b. The time dependence of glass beads and Toyoura sand was hardly observed. Although the glass beads have some cementation effects, they can be easily collapsed in a large strain level. The glass beads have some effects to increase liquefaction resistance and shear modulus. Therefore, ground improvement using this phenomenon can be expected in practice. However, note that drained shear strength and penetration resistance are lower than those of ordinary sands.