To study the deformation behavior of large-diameter grouted pile in extra-thick fine sand layer

load transfer of large-diameter grouted pile was analyzed in a case study of eight in-situ pile load tests of Shishou Yangtze River Highway Bridge. The BoxLucas1 load transfer function was used to calculate the relationship between load and settlement of the grouted pile considering the radius of the grout bulb and the thickness of cement grouting along the pile. The empirical range of enhancement factors for side friction and tip resistance in different soil deposits was also given. Then

case history was cited to demonstrate the validity of the method. Finally

according to the engineering example and calculation method of this paper

the bearing capacities of the large-diameter pile under extra-thick fine sand layer were further analyzed. The results show that the presented method can well determine the range of settlement of the grouted pile. It is suggested that the calculated lower bound can be used as an engineering design. The bearing capacity of the large-diameter pile is gradually increasing with the increase of pile diameter or pile length. When the pile diameter is constant

the increased range of bearing capacity of the large-diameter pile is decreased with the increase of pile length. The pile length reaches a certain value

the ratio of the mobilized base resistance to the total capacity is almost zero. This indicates an effective pile length problem by increasing the pile length to improve the bearing capacity of large diameter pile. Effective pile length

bearing capacity and percentage of load carried by pile tip of the large-diameter pile can be significantly improved by combined grouting of pile tip and side.