Investigation of the behavior of shallow machine foundation resting on a saturated layered sandy soil subjected to a dynamic load

In liquefying soils, Shallow foundations may experience an increase in settlement and displacement due to dynamic loading. Therefore, the machine footing may settle and tilt excessively. In this paper, the settlement of shallow foundation and inner displacement on liquefiable of unreinforced and reinforced saturated multi-layered sandy soils (medium-dense sand MD) will be studied. The relative density of the first and second layers is 50% and 85% corresponding to medium sand soil and dense sand soil respectively. The tests have been carried out on 20 models. The amplitudes of the applied harmonic load are 0.25, 1 and 2 tons with frequencies of 0.5, 1 and 2 Hz. The used foundation was with dimension 200*200*20 mm and the geogrid was used as reinforcement material. For each amplitude and frequency of load, the sand models were tested without and with reinforcement in various configurations (0.5B, 1B using single reinforcement layer and 0.5B, 1B using double reinforcement layers) where B is the square footing width. The results showed the high susceptibility for liquefaction and its potential which increased with increasing amplitude load and amplitude frequency. Also, the surface settlement and displacement were increased in the first layer and reduced with increasing relative density. The results also showed the high effect of reinforcement material and its configuration and number of layers by maintaining the little settlement values when fixing other parameters.