Spread Foundation Behaviors in Reinforced Aeolian Sand under a Combination of Uplift and Lateral Loadings

This study elucidated the field tests on behaviors of the spread foundations with centrically vertical pier, vertical but offset pier, and battered pier in geogrid-plannar-reinforced Aeolian sand under a combination of uplift and lateral loadings, which was compared with the parallel studies of the same foundations in Aeolian sand. The site conditions, the arrangement of reinforcing geogrid, and the load tests were documented comprehensively. A dimensionless breakout factor was presented to reflect the difference of foundation types. Under a combination of uplift and lateral loadings, the uplift-displacement curve exhibited a two-phase behavior, while the corresponding lateral displacement gradually increased with the load, apparently without two-phase behavior. Under a combination of uplift and lateral loadings, the foundation type had an obvious effect on the load-displacement behaviors. The spread foundations with vertical, but offset, pier or battered pier could have a better load-bearing capacity than that of the foundations with centrically vertical pier. Due to the higher tensile capacity of the geogrid and the frictional resistance between the geogrid and the sand mass, the geogird-reinforced Aeolian sand could behave as a much stiffer system to improve the uplift and lateral bearing capacity of the spread foundations.