Simple Model for Nonlinear Response of 52 Laterally Loaded Piles

Abstract

The response of a laterally loaded pile is normally dominated by the limiting force per unit length profile (LFP, pu) mobilized along the pile to the depth of the plastic zone (e.g., maximum slip depth, max xp) and depends on pile-soil relative rigidity (via the subgrade modulus of elasticity k). The values of pu and the shear modulus (G, thus k) were deduced extensively against the measured response of 32 and 20 piles tested in situ in clay and sand, respectively. In this paper, simplified closed-form solutions are presented for the design of laterally loaded piles. The parameters of the pu and the G obtained previously are utilized to examine the impact of loading eccentricity on piles and to assess the validity of existing pu-profiles. Expressions are also explored and provided regarding determinations of the pu-profiles, the modulus of the subgrade reaction k (via G), the ranges of the plastic zone (max xp), and the depth of elastic influence (via the critical pile length Lcr), along with the correlations between the shear modulus of soil G and undrained shear strength (su) and/or the standard penetration test blow count (N). It is noted that the popularly adopted LFPs (such as Matlock’s LFP, Reese’s LFP, and American Petroleum Institute code methods) are not sufficiently accurate for 60–85% of the 52 piles investigated herein, especially for those with a diameter >1.5 m.