However, with the gradual improvement of building requirements for the control of settlement and differential settlement, it is very wasteful to meet the requirements by increasing the safety factor for the reason that pile-to-pile interaction and pile-soil-pile interaction always exist in PRFs. The stiffness distribution of the pile group is always uniform for the convenience of design and construction. During the traditional design of pile foundations, a large safety factor is always used to control the settlements and differential settlements. Piled raft foundations (PRFs) have been used for many years as a method of transmitting the loads from the superstructure to competent strata at depth in the ground. This study can help practicing engineers optimize the pile lengths in pile groups to satisfy higher differential settlement requirements. The results show that the optimization method proposed in this paper has high efficiency and stability. The differential settlements of the raft in different cases are all reduced by nearly or more than 80% after optimization design. Two cases with different safety factors that suffer different kinds of surface loads (uniform load and nonuniform load) are used to verify this method.

ANSYS software, in conjunction with nonlinear elastic soil model, is used to analyze piled raft foundation models. The pile lengths were adjusted via the relationship between load, settlement, and the length of single piles during the optimization design. In order to reduce the differential settlement of piled raft foundations, an optimization method based on pile-to-pile interaction theory is proposed in this paper, which translates the problem of pile-to-pile interaction (PPI) in pile groups into that in single piles using the interaction factor method.

Sim settlements load order