Numerical Procedure for Predicting Pile Capacity—Setup/Freeze

Abstract

In geotechnical engineering practice, the increase over time of pile capacity after installation is sometimes referred to as pile setup or freeze. Pile setup, which is often associated with piles driven into saturated clays and silts, is mainly attributed to soil consolidation around the pile. Field observations have shown that pile setup is significant and continues to develop for a long time after pile installation. Pile foundations are usually expensive. Therefore, taking a small percentage of pile setup into consideration will result in cost reduction and savings in piling projects. This paper presents a general numerical procedure to predict pile setup by simulating the behavior of the pile during its different life stages: installation, subsequent consolidation, and loading. The Hierarchical Single Surface modeling approach, the strain path method, and the nonlinear finite element analysis of porous media were used in the analyses. The procedure was verified by successfully predicting the field behavior of pile segment models installed into soft marine clay. Numerical experiments were also conducted to demonstrate the applicability of the numerical procedure to full-scale driven piles. Piles with diameters of 0.3 m and 0.5 m and a length of 10 m were considered in the analyses.

A Method For Accounting For Pile Setup and Relaxation in Pile Design and Quality Assurance

“…This increase has become known as pile setup. Effect of time on the capacity of displacement piles has been studied in the literature, both experimentally (Karlsrud and Haugen 1985, Axelsson 2000, Komurka et al 2003, Skov and Denver 1988, Chow et al 1998, Cho et al 2000, Bullock 1999, Long et al 1999, Cooke et al 1979, Coop and Wroth 1989, Augustesen 2006) and theoretically (Randolph et al 1979, Whittle and Sutabutr 1999, Titi and Wathugala, 1999. When a displacement pile is driven or jacked into the soil, it displaces a soil volume equal to the volume of the pile.…”

Setup of Driven Piles in Layered Soil

“…Baligh (1985) introduced the strain path method (SPM) as an approximate analytical technique to predict soil disturbance caused by the insertion of a variety of devices (e.g., long piles, in situ testing tools, soil samplers) in the ground. A number of researchers have since used the SPM in the attempt to gain some insight into pile set up (Titi and Wathugala, 1999;Baligh, 1985;Whittle and Sutabutr, 1999). In the SPM, the soil is treated as a viscous ‰uid, and a ‰owˆeld is established that satisˆes incompressibility (Lu et al, 2004).…”

Evaluating pile installation and subsequent thixotropic and consolidation effects on setup by numerical simulation for full-scale pile load tests

“…Therefore, other approches such as the strain path method or cavity expansion theory coupled with finite element analysis have been adopted by some researchers (e.g., Wathugala, 1990;Shao, 1998;Titi, 1999) to calculate the generated excess porewater pressure during pile driving.…”