Applicability of critical void ratio theory for liquefaction potential assessment of Rubber Sand Mixture (RSM)

抄録

It is well known that waste rubber disposal poses many serious environmental problems. Nevertheless, many researchers have utilized it for various geotechnical applications such as highway embankments, lightweight backfill materials, seismic isolation, and landfill leachate drainage material. Lately, the use of rubber sand mixture for liquefaction mitigation has started gaining attention. The literature indicates that the addition of rubber in the sand has the potential to increase liquefaction resistance even in a loose state. On the other hand, the theory of critical void ratio indicates that soils having a void ratio above the critical void ratio line should be liquefiable. The present study aims to evaluate the applicability of the critical void ratio theory for rubber sand mixtures. A series of consolidated drained tests has been carried out on the pure sand, rubber sand mixture and pure rubber to evaluate the critical void ratio of the material; then, the cyclic tests are carried out on specimens having a void ratio above the corresponding critical void ratio line. The results show that the critical void ratio reduces with the increase in rubber content. However, despite being highly contractive materials, rubber-sand mixtures develop lower excess pore water pressures during cyclic loading, thus contradicting the expected behaviour of granular soils and the role of the critical void ratio line, which does not play anymore a relevant role to predict the liquefaction potential.