Análise numérica de cravação de estacas torpedo modeladas por integral de pressões

Abstract

In deep-water offshore oil exploration, the mooring foundations are usually submitted to high loads in a soil that is, usually, extremely soft. To circumvent this problem, torpedo anchor is frequently used to fix the mooring line on seabed. In this context, this paper presents a new numerical approach to represent the soil reaction of torpedo anchor, in a global analysis tool to model its installation procedure, via a numerical integral of soil pressures on its penetrated surface. Therefore, this method is associated to the weak coupling formulation in time domain, in which the torpedo is represented by a rigid body with six degrees of freedom and the mooring and launching lines are represented by finite elements. The method was developed on in-house program SITUA-Prosim and compared to the classic True model. In this numerical procedure, a typical impact velocity and physical data were used to represent a real launching procedure evaluated in Campos Basin-Brazil. The geometric factors (presence of wings and tip) and the variation of the soil drag coefficient were evaluated as parameters of influence in the embedment depth of the anchor.