Numerical and experimental investigations of granular anchor piles in loose sandy soil subjected to uplift loading

The granular anchor pile (GAP) system is one of the relatively new innovative ground-improvement techniques used to sustain the tensile loads. This paper presents the behavior of a GAP system in a loose sandy soil. The small-scale laboratory tests were conducted on a loose dry sand to investigate the effect of embedded length of pile on the uplift capacity of the GAP system. The results were compared with the numerical analysis using a three-dimesional finite-element analysis software. In the detailed numerical study, the effects of key parameters, such as length (L) and diameter (D) of pile and the elastic modulus of surrounding soil, on the uplift capacity of the GAP were examined. The load-displacement response of the GAP was also analyzed and is reported in this paper. For a constant diameter of the GAP, its ultimate uplift capacity increases as the L/D ratio increases. However, for L/D ratios greater than 10, further increase in the L/D ratio does not contribute to the load sharing significantly. The bulging failure predominantly occurs in the GAP with a higher modulus ratio, whereas the shaft failure occurs with the lower modulus ratios