Sand-granulated rubber mixture to prevent liquefaction-induced uplift of buried pipes: a shaking table study

Buried pipelines in liquefiable soils are vulnerable and can float during earthquake excitation. The uplift forces due to pore-water-pressure generation relocate the pipelines in the soil. Therefore, it is essential to measure the liquefaction effects of the backfill materials on buried pipes and make an intelligent choice for the surrounding soil to reduce the applied forces on pipelines during liquefaction. Recently, scrap tire–soil mixtures have been used as a new geomaterial to decrease the adverse effects of liquefaction. This paper investigates the flotation of the buried pipe and the sand–granulated rubber mixture’s effectiveness around the pipe by a series of shaking table tests. Dynamic tests were performed under 1 g conditions on a fully saturated sand–granulated rubber mixture with small-diameter buried pipes. Three different granulated-rubber dimensions of 2.5–5, 5–10, and 10–15 mm and granulated rubber ratios of 10, 20, and 30 percent were examined in the tests. The outcomes of excess pore water pressure, settlement, pipe uplift, and upward pressure during and after shaking were compared. The test results demonstrated that the sand–granulated rubber mixture reduces excess pore water pressure accumulation and prevents liquefaction. Moreover, the effect of pipe diameter, burial depth, consolidation coefficient of the mixture, and uplift initiation time on pore water pressure and load increment below the pipe were combined to predict the buried pipe’s uplift probability.