Evaluation of Liquefaction Potential in Sand–Tire Crumb Mixtures Using the Energy Approach

Abstract

This research explores performance of the energy approach for evaluating the liquefaction potential of sand–tire crumb mixtures. Thirty-six stress-controlled undrained cyclic torsional tests were performed under three different confining pressures on samples with different rubber contents. The effect of such parameters as the rubber content and confining pressure on liquefaction behavior of sand–rubber mixtures was studied using the energy approach. Test results indicated that, unlike the observations made on the pure sand sample, in the case of sand–rubber mixture with 25% rubber content, when the initial liquefaction is triggered, the dissipated shear energy increases with continued cyclic loading. The increasing trend is stopped when the pore water pressure reached the initial consolidation stress (Ru = 1). This observation indicates that for the case of sand–tire crumb mixture, the dissipated energy per volume is associated only with the progression of pore water pressure. Moreover, the results show that the required energy for liquefaction occurrence decreases with the increase in the rubber content. The minimum amount of required energy is determined for mixtures with 10% rubber content. As the result, the inclusion of crumb rubber decreases the liquefaction resistance of sand. However, when the rubber content increases from 10 to 25%, the resistance to liquefaction improves. The generation rate for mixture with 25% rubber content is somewhat faster than that of the clean sand and the mixture with 10% tire crumbs, as it is expected.