Load transfer and performance of an improved grouted enlarged toe (GET) precast concrete pile

An improved grouted enlarged toe (GET) precast pile is proposed in this study. The GET technology improves the bearing capacity of precast concrete piles by enlarging the pile toe and solidifying soil surrounding pile shaft. In this study, the soil densification due to the GET technology is first investigated by developing an analytical solution for the soil deformation around the pile shaft, in which the pile toe expansion is generalized as an oblate spheroid. The results of this solution show that the GET pile can alleviate ground surface deformation. Secondly, a multi-layer load transfer (MLT) method is proposed to describe the pile-solidified soil–ground interaction, which allows assessing the performance of the GET pile. In addition, full-scale conventional precast reinforced concrete pipe and GET piles were constructed and load tested at two field sites. The test results demonstrate that the bearing capacity of GET piles is significantly improved compared to the conventional pipe piles, with an increase ranging from 36% to over 60% under varying site and construction conditions. Finally, the load–settlement curves obtained from the proposed MLT method were in good agreement with the results obtained from the static load tests, which confirmed the ability of the MLT method to reliably predict the pile performance under axial loading.