The arching effect in rubber–sand mixtures

Arching effect in geomaterial refers to the stress redistribution as a result of induced displacements. It is most likely to occur in different situations such as retaining walls, piled foundations, tunnelling, and so on. The arching effects that occur in rubber–sand layers are examined in this paper. The digital image correlation technique and a series of pressure sensors were employed to capture the deformation characteristics and stress evolution developed in the sand and rubber–sand layers, which were subjected to active arching with and without a central surcharge in a trapdoor apparatus. A range of deformation measures, including horizontal and vertical displacements and strains, shear strains, and volume change variables were obtained and compared for different backfill materials. Ground response curves for sand and rubber–sand mixtures were developed using the stress measurement data. From the deformation data, an arch of equal displacement was introduced. It was observed that the use of rubber particles reduced the surface settlement of the sand layer and the arch heights, and higher stress reduction was obtained in the rubberised backfills.