EXPERIMENTAL INVESTIGATION ON LOAD SHARING OF SOIL AROUND PILES AND UNDERNEATH RAFT ON PILE GROUPS

Elsamny M.K, Ibrahim M.A, Gad S.A, Abdel-Mageed M.F

Abstract: Determination of load sharing between soil, piles and underneath pile raft is a complex geotechnical task.Thus, experimental investigation is a simplified method to predict the load sharing between soil, piles and underneath pile raft. The purpose of the current study is to investigate experimentally the load sharing between soil and pile raft in cohesionless soil. The distributions of applying loads to the lower parts of founded soil as well as pile raft were determined by experimental investigation program. The experimental investigation program consisted of testing pile groups of one, two, three, four, five and six piles in sand. The program consisted of installing test piles in dense compacted sand with spacing of three diameters subjected to compressive axial load. The pile head loads, displacement, strains along the piles shaft as well as transferred loads underneath pile raft were measured simultaneously. The loads transferred to soil underneath pile caps (raft) and to soil at pile tips were measured by load cells. In addition, the distribution of loads along pile shaft was determined from five strain gauges readings mounted on the longitudinal reinforcement of piles. Moreover, the sharing loads between resisting soil underneath the caps (raft) and piles have been determined. However, for single pile it was found that the percentage of the transferred load at the pile tip = 13.50 % from the ultimate capacity. In addition, for single pile it was found that the percentage of the transferred load by friction = 86.50 % from the ultimate capacity. For pile groups (2, 3, 4, 5 and 6 piles), it was found that the percentage of loads transferred to the soil underneath the pile caps = 0.88 to 1.10 % from the ultimate bearing capacity. In addition, for pile groups (2, 3, 4, 5 and 6 piles), it was found that the percentage of loads transferred to the soil at pile tip = 4.20 to 2.53 % from the ultimate bearing capacity. However, for pile groups (2, 3, 4, 5 and 6 piles), it was found that the percentage of loads transferred to the soil by friction = 94.70 to 96.59 % from the ultimate bearing capacity.

Keywords: Piles; load sharing analysis; loading test; pile groups; strain gauges; experimental

DOI: https://doi.org/ 10.15623/ijret.2017.0608005