Numerical Analysis Of Penetration And Uplift Of Integrative Suction Foundation For Tension Leg Platform

Tension Leg Platform (TLP) is widely applied to the oil exploitation in deep sea now, whose foundation is either suction bucket or pile. Because of bad geological condition in blue water, the suction foundation is more suitable for TLP than pile. But now, the depth of water where the suction foundation is used for TLP can't satisfy the requirement of oil exploitation in deep sea. Thus we advance the integrative suction foundation project for TLP. The four suction buckets under the tension legs are connected together to form an integrative one, which can increase the uplift effect and stability of each bucket. Because the buckets are penetrated to the soil together, the installation time in the sea is also shortened.But there are some failures of penetration or uplift in the application of bucket foundation, which demands us to analyze the penetration and uplift quantificationally.For the problems faced in the research of the integrative suction foundation, this paper analyzes the penetration and uplift effect of integrative suction foundation in the clay or sand environment by using finite element software PLAXIS. The penetration process can be divided into self-weight installation, reconsolidation and suction penetration. The depth of self-weight installation is obtained by staged construction. The reconsolidation of soil after self-weight installation is analyzed to summarize the rule of dissipation of excess pore-fluid pressure. The allowable negative pressure is calculated with critical hydraulic gradient method by using ANSYS. The calculation between actual construction negative pressure and friction reduction factor induced by seepage is iterative. The simulation of seepage field is performed with PLAXIS to confirm the actual construction negative pressure. The uplift effect is simulated by using the interface element along with seepage field. The viable numerical calculating procedure is searched out to apply to practice better.