P–y curve and lateral response of piles in fully liquefied sands

Abstract

This paper provides a technique to assess the response of laterally loaded piles and associated p–y curves in fully liquefied soils (where p is the soil–pile reaction and y is the pile deflection). The technique accounts for the variation of water pressure in the liquefied soils around the pile and its impact on the shape of the p–y curves and the pile lateral response. A constitutive undrained stress–strain model for fully liquefied saturated sands using the basic properties of sand is established to predict the post-liquefaction varying resistance of liquefied sands at different levels of loading assuming fully undrained conditions. The degradation in soil strength due to the free-field excess pore-water pressure (uxs,ff), caused by an earthquake and resulting in full liquefaction, is considered along with the near-field excess pore-water pressure (uxs,nf) induced by lateral loading from the superstructure. The presented procedure also accounts for the influence of the overburden pressure and sand density on the variation of excess water pressure in the near-field soil, the rebound of sand strength, and the shape of the p–y curve due to the dilative behavior of sands.