DFI Journal - The Journal of the Deep Foundations Institute
Volume 19, Issue 2, November 2025
DOI: 10.37308/DFIJnl.20250129.320
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Load Tests and Numerical Modeling of Drilled Displacement and Driven Piles in Marl in Savannah, Georgia
Article Type: Research Paper
Zhoa, Zhihao, et al.
Abstract
The Miocene formation called Marl is a stiff, calcium carbonate-rich, over-consolidated fine-grained soil commonly utilized as a bearing layer for pile foundations. However, conventional Cone Penetration Test (CPT)-based methods have generally been found to underestimate pile resistance in this stiff marl. The challenge in predicting pile behavior is further complicated by the marl’s brittle, strain-softening characteristics, which can lead to plunge failure of piles. This research aims to document a comprehensive load test program for precast prestressed concrete (PSC) piles and drilled displacement piles installed in marl in Savannah, Georgia. Based on the test data and historical data, the study proposes improvements to CPT-based resistance estimations and suggests refined load-transfer curves (e.g., t-z and Q-z) for these piles in marl. The proposed methods are validated against an independent set of test data.
Keywords:
Driven pile, drilled displacement pile, marl, numerical simulation, t-z method, CPT correlation