Behaviour of Granular Anchor Pile (Gap) and Group Piles In Different Type of Soils under Vertical Pullout Loads

Abstract

In the present study, the load displacement behaviour of Granular Anchor Pile (GAP) and Group piles under vertical pullout loads in two different type of cohesionless soils have been investigated. The main objective of the study is to investigate the effect of embedment length, diameter and spacing varying (L/D and S/D ratio) on Pullout Capacity of Granular Anchor Pile system in different type of soils. GAP pile is innovative and effective in resisting the uplift pressure exerted on the foundation. Based on the laboratory study on single and group of 2 and 4 GAP systems, it is found that the ultimate Pullout Capacity of single GAP system increases with the increase in length (L) to diameter (D) ratio in both type of soils. The rate of increase of ultimate pullout capacity of single GAP systems having 50 mm diameter and 100 mm diameter was significant up to increase in L/D ratio of 39%. Thus, it was inferred that for single GAP system, there is maximum advantage upto L/D ratio 10.50 for 50 mm and 7.00 for 100 mm. In case of medium dense soil with higher relative density, the increase in pullout capacity is more as compared to loose soil with lower relative density. It was further confirmed that ultimate pullout capacity is a function of diameter of GAP and soil characteristics. The ultimate pullout capacity of group of 2 and 4 GAP systems with 100 mm diameter was found to increase with S/D ratio upto 3.00 and 2.75 respectively only in both the soils.