Comparison Between The Mixed-In-Place Technology and Driven Piles as Offshore Foundations

Abstract

In certain ground conditions, open-end driven piles are not a suitable foundation option. In calcareous sand, driven piles may cause particle breakage which leads to high levels of contraction and very low pile shaft capacities. The traditional alternative to driven piles is to employ a drilled-and-grouted pile system (D&G), which is however time consuming and expensive. The MIDOS (MIxed Drilled Offshore Steel) pile is a novel pile that utilizes the mixed-in-place (MIP) technology as an alternative to D&G piles. One of the key environmental advantages relative to driven piles is the reduced noise levels during installation. The following paper summarizes the in situ tests performed in quartz sand (with interbedded clayey layers) and laboratory tests on calcareous sands. Preliminary calculations were undertaken to assess the length required to support the design loading at ultimate capacity for a driven steel tube pile and an equivalent MIDOS pile. The results show that the MIDOS pile can provide significant savings in pile length when compared to a driven, open-ended steel pile with the same loads and ground conditions in silica sands and even more in calcareous sands.