Experimental Study on the Factors Influencing the Performance of Geogrid Encased Granular Pile Anchor Installed in Cohesionless Soils

Abstract

The increasing demand of infrastructure at the global level necessitated the importance of ground improvement and efficient foundation design techniques to cater special loads (e.g., tensile loads). Geogrid encased granular pile anchor (GGPA) is an advanced ground improvement technique which is capable of improving the pull-out capacity to counter the tensile loads in addition to the compressive loads. The present study focusses on the experimental investigation on Swan sand specimen treated with GGPAs under varying the length-by-diameter (L/D) ratio of the pile (5, 10, 13.3, and 16.6), angle of pile inclination (5°, 10°, and 15°) and relative density of the sandy soil (45%, 55%, and 65%). Increment in pull-out capacity has been observed with the increased angle of pile inclination and relative density. Encasement through geogrid increases the interface friction between soil–pile surface and cohesionless soil, and reduces the bulging of pile. Thus, the failure of the GGPAs was completely governed by the shaft failure of the pile and not much influenced by the pile bulging. From the experimental observations, it is clear that the efficiency of the GGPAs mainly depends on the length and diameter of the pile apart from pile inclination and relative density and not purely depends on L/D ratio.