Performance of Soil Embankment Model under Static and Cyclic Loading

The sandy soil with high gypsum content, (usually referred to as gypseous soil), possesses a type of cohesive forces when mixed with optimum amount of water and then compacted, but losses its strength when flooded with water again. The gypseous soil obtained from Al-Fallujah was subjected to laboratory investigation. The physical and chemical properties and then optimum liquid asphalt (emulsion) requirement were determined. A laboratory soil embankment-model of 50x50x30 cm was implemented to study the impact of absorption by capillary rise on the stability of embankment. Load repetitions test was carried out on four gypseous soil models, two of them were pure soil at dry and absorbed conditions, and the other two were stabilized with emulsion at dry and absorbed condition. Another set of four gypseous soil models of the same condition were tested under static load. The impact of changing the hydraulic conductivity of soil due to asphalt stabilization was investigated and the vertical deformation was determined using LVDT. For the pure soil in dry condition the vertical deformation was 7.45 mm at 157 load repetitions, while for pure soil model under absorbed condition, the vertical deformation was 12.5 mm at 29 load cycles. The stabilized soil at dry condition exhibits vertical deformation of 9.75 mm at 911 load cycles, and shows 10.47 mm deformation at 897 load cycles under absorption. When tested under static load, the ultimate sustained pressure was 0.8 MPa with vertical settlement 0.03 mm for pure soil at dry condition, and reduced to 0.3 MPa with vertical settlement 12 mm at absorbed condition.