This paper is on 3-D analysis of piled raft foundations on sand. The numerical analysis was carried out with three typical load intensities of the serviceability load. Further, extensive parametric studies were carried out with the variables pile spacing, number of piles, pile diameter, raft dimension ratio, and raft thickness. The maximum settlement of the piled rafts depends on the pile spacing and the number of piles; while the raft thickness does not have a significant effect. In all cases, the normalized settlement recorded is mostly less than 2% of the raft width and the maximum value was noted for the 8x27m piled raft. The increase in raft thickness reduces the differential settlement in the foundations. The raft-soil stiffness (Krs) is shown to influence the differential settlement and has the largest influence. The performance of piled raft in sandy soil condition is assessed and general conclusions are also made.
This paper is on a detail 3-D analysis of piled raft foundations using the PLAXIS. A six-layer soil model is adopted which is commonly encountered in Surfers Paradise of Gold Coast. The numerical work is carried out on 3-D PLAXIS analysis. Extensive parametric studies were carried out with the variables pile spacing, number of piles, pile diameter, raft dimension ratio, and raft thickness. Historically, the pile raft analysis has its origin to the pile group analysis. The early work of Skempton (1953) and Meyerhof (1959) were empirical in nature and relates to the settlements of pile groups. The important work of Fraser and Wardle (1975), Poulos and Davis (1980), Randolph (2003), and Poulos (2006) are reviewed in relation to the pile group analysis, load transfer mechanism and other pertinent aspects related to the fundamentals of pile group analysis. The contributions from Tomlinson (1986), Coduto (1996), Poulos (1993) and Van Impe (1991) are also studied in relation to the equivalent raft methods of analysis.
