SHAFT RESISTANCE OF PILES IN CLAY

A new method is proposed for elucidating, formulating, and predicting the axial capacity of friction piles in moderately overconsolidated clays (1≤OCR≤4) within a systematic and rational framework. The paper focuses on single, vertical, rigid, and cylindrical piles driven in deep deposits which exhibit normalized behavior. The normalized limiting skin friction, β(=fs/σvo′), during rapid monotonic undrained axial loading is written as the product of a lateral earth‐pressure coefficient, Kc(=σhc′/σvo′) at the end of soil consolidation, which follows pile installation, and a skin‐friction ratio, ρ(=fs/σhc′). Important factors affecting Kc are shown to include the overconsolidation ratio (OCR) of the clay and its sensitivity. The friction ratio, ρ, is not sensitive to the in situ OCR of the deposit and corresponds to the normalized peak‐strength ratio, cu/σvc′, in undrained direct simple shearing of the clay at an OCR=1.2(±0.1).