Pile Settlement in Liquefying Sand Deposit

Abstract

Model studies have shown that end‐bearing pile settlement in a saturated sand deposit is very sensitive to excess pore pressures induced by earthquake shaking. Settlement amounting to pile failure will be reached before liquefaction occurs, for pile safety factors in the 1.5 to 3 range Variables considered in the program were effective stress level, relative density and stress history of the sand, diameter and safety factor of the pile. Tests were carried out in an apparatus designed so that the model pile tip could be inserted into a saturated sand mass under effective stress levels of up to 40 psi,(276 kPa). Excess pore pressures were then induced by applying cyclic load to the sand in undrained conditions. Tests with piles of three diameters showed consistent behavior when corrected for apparatus boundary conditions.)These results may therefore serve as an element of judgment in predicting the behavior of fullsize piles.