Behaviour of machine foundations resting on saturated sand granular tire rubber mixtures

Abstract

This study aims to investigate the behaviours of machine foundations resting on sand granular tire rubber mixtures after saturation. Kerbala sand with two relative densities, 35% and 60%, and granular rubber of sizes 0.07 to 3 mm, resulting from hashing scrap tires into small pieces, were used. A harmonic vertical mode of vibration was applied using a mechanical oscillator fixed on a square steel footing (200 × 200 × 20 mm). The footing was rested on sand inside a steel box of size 1200 × 1200 × 900 mm. Nine model tests were carried out on saturated sand to study the effects of 0, 8, and 12% mix ratios and 0.5 B and 1 B mixing depth for the two relative densities and two frequencies (69 Hz and 80 Hz) in terms of displacement amplitude, settlement, and excess pore water pressure generation in soil. The same number of models were tested for a comparison of dry sand under the effects of the same parameters. The results showed that, in general, the displacement amplitude decreased and the settlement increased for saturated sand compared to dry sand under the same conditions. Mixing granulated tire rubber with saturated sand decreased the displacement amplitude, settlement, and excess pore water pressure; the range of percentages of reduction were from 19% to 73%, 40% to 70%, and 24% to 60% respectively.