PileAXL Validation Examples
This example involves a 1.4 m diameter reinforced concrete bored pile installed through fill, soft marine clay, firm clay and dense clayey silt layers and socketed into weak siltstone in Singapore based on the case studies from Leung (1996).
The subsurface profile consists of 3 m thick fill, 2 m thick soft marine clay, 3m thick firm silty clay followed by dense clayey silt of about 2.5 m thick. The bottom part of the pile is located in a 5.5 m thick deep rock socket of highly fractured, very weak to weak siltstone. The unconfined compressive strength of the upper and lower parts of the rock socket is 3.5 MPa and 6.5 MPa respectively. A maximum test load of 20 MN was applied on the pile and this is adopted in this example to calculate the load settlement curve.
This presents a design example for a 1.2 m diameter reinforced concrete bored pile installed through interbedded clay and sand layers in Singapore.
The typical subsurface profile at Marina Bay in Singapore consists of 12 m thick reclamation fill, 12 m thick very soft marine clay, 7 m thick fluvial sand followed by Class B old alluvium (very dense fine to medium grained silty sand) which overlies Class A old alluvium (very dense fine to coarse grained silty sand).
This blog presents a case study for an example documented in Appendix B1 of the book of "ICP Design Methods for Driven Piles in Sands and Clays” by Jardine et al. (2005) using the PileAXL program. This case is part of the testing programme selected by the Joint-Industry EURIPIDES project for large diameter pile tests in dense sand at Eemshaven in the Netherlands.
Kraft et al. (1981) details the results of axial loading tests on single piles and pile groups driven into a stiff over-consolidated clay at a site located on the University of Houston Campus. The piles were closed end tubular steel pipes with Young’s modulus of 210GPa, external diameter of about 274 mm, wall thickness of 9.3mm and penetration depth of about 13.1m (43 ft).
This case is analyzed with PileAXL program with adopting USACE method to estimate the ultimate shaft resistance and end bearing resistance of stiff over-consolidated clay. The soil parameters are based on the undrained shear strength profile presented by Kraft et al. (1981), which are interpreted primarily based on unconsolidated-undrained tests with simplified constant values for different soil layers.