Study of Liquefaction Characteristics of Saturated Sand–Rubber Mixture Under Cyclic Torsional Shear Loading

Scrap tire-derived geomaterial has been gaining attention recently as an alternative material for improving the ground. This paper presents a fundamental experimental investigation into sand–rubber mixtures using hollow cylinder torsional shear apparatus, with the aim of enhancing our understanding of the integrated effects of rubber content and cyclic stress ratio (CSR) on the liquefaction characteristics of the mixtures. The results show that the incorporation of granular rubber into sand not only reduces excess pore water pressure during cyclic loading but also alters the generation mode of pore water pressure. The liquefaction resistance of the sand–rubber mixture increases significantly when the rubber gravimetric proportion exceeds 10%. The energy dissipation per loading cycle decreases with increasing rubber content, whereas the cumulative dissipative energy exhibits an opposite trend, showing a positive correlation with rubber content. In addition, this rubber-enhanced effect shows CSR dependence; the cumulative energy dissipation significantly diminishes at a high CSR. Therefore, the effect of granular rubber addition to sand on pore water pressure tends to become more pronounced at higher rubber contents.