Time-dependent behavior of pile groups by staged construction of an adjacent embankment on soft clay

Abstract

A series of centrifuge model tests were performed to investigate the behavior of pile groups subjected to lateral soil movements by surcharge loading from approach embankments. The emphasis was on quantifying the time-dependent response in terms of deflections, bending moments, and earth pressures acting on pile groups during embankment construction and over short- and long-term periods after embankment construction. A variety of instruments were used to examine the soil–pile interaction for pile groups adjacent to surcharge loads. Through these studies, it is found that pile cap deflections and bending moments developed to their maximum values under the short-term surcharge loading and decreased gradually to minimum values under the long-term loading. The ground settlement reached its maximum value under long-term loading, however, due to the consolidation of soft clay. It is also found that the lateral mean pressure acting on the pile is about 0.75 and 0.35 times the surcharge load q (= γH, where γ is the unit weight of the soil and H is the height of the embankment) under short- and long-term loading, respectively.Key words: time-dependent response, lateral soil movements, pile groups, centrifuge model tests, surcharge loads, soft clay.