Estimation of the compression and tension loads for a novel mixed-in-place offshore pile for oil and gas platforms in silica and calcareous sands

The behaviour of calcareous (or carbonate) soils often presents significant foundation challenges regarding the construction of offshore hydrocarbon facilities. The presence of carbonate deposits at many strategic petrochemical reserves implies the necessity to study the behaviour of these soils. Driven piles, normally used as deep foundation elements for oil and gas platforms are normally avoided in these geological conditions as the impact operations lead to a degradation of the sand properties decreasing the shaft capacities. Drilled-and-grouted (D&G) piles overcome many of the technical limitations associated with impact piling in carbonate deposits, however D&G piles are both expensive and time consuming to construct. A novel mixed-in-place pile has been developed that provides a technically and economically efficient solution for carbonate soils. This technology minimizes the number of offshore operations and is therefore significantly quicker than D&G piles and therefore more cost effective. Several laboratory tests and in situ tests have been performed to assess its behaviour in both silica and carbonate sands. This research uses the results of recent laboratory experiments on the mixed-in-place pile on both silica and calcareous sands to develop a Finite Element Model (FEM) of full scale piles to test their potential bearing capacities for oil and gas platforms.