Experimental and numerical study on the bearing capacity of single and groups of tapered and cylindrical piles in sand

This study is intended to investigate the bearing capacity of tapered and cylindrical pile groups experimentally and numerically. Tapered and cylindrical concrete model piles were loaded as single and 2, 3 and 4 piles in groups. Using load-settlement curves obtained from tests, the bearing capacity of single and group cylindrical and tapered piles were calculated and compared. Then the tests were modeled and verified using finite element method. Then the influence of the number of piles and their spacing on group efficiency were investigated numerically. The results of this study show that maximum group efficiency of tapered piles is reached in a greater center to center distance than cylindrical piles. It was found that the coefficient of group efficiency increases with increasing the number of piles in a group in certain piles spacing. It was also revealed that common relations do not predict the group efficiency of cylindrical piles well.