Construction Effects on ACIP Pile Behavior in Texas Coastal Soils

In this study, the finite element method was used to simulate the construction effects on the behavior of an Augered Cast in Place (ACIP) pile installed in the Pleistocene terrace formation of Texas Gulf Coast. A mixed soil profile, typical for the Gulf Coast, was considered. The construction effects were modeled by taking into account stress changes during drilling and grouting and by assigning modified properties (c^', φ^', E) due to remolding in the soil surrounding the pile. Due to the construction procedure, the ACIP pile is expected to affect the surrounding soil differently compared to a bored pile or a driven pile. The validity of the assumptions was assessed, by comparing numerical analysis results to full scale test data. Furthermore, the importance of the construction effects was demonstrated by comparing to the wished-in-place pile case. The various stages of the ACIP pile construction were modeled numerically by using the commercially available F.E. code PLAXIS and by adopting the hardening soil model (HS). The numerical analysis showed that load settlement behavior of an ACIP pile installed in Texas Coastal Soils gave realistic settlement results when construction effects were considered, while it significantly underestimated the settlement in the case where the pile was wished in place.