Numerical Modeling And Investigation Of The Dynamically Embedded Circular Plate Anchor Installation

Mooring the floating platform at the bottom of the sea through a safe and reliable mooring system is a key issue to exploit deep sea oil and gas resources.The dynamically embedded circular plate anchor(DEPLA)presented in recent years is a new form of deep sea plate anchor foundation.Its installation process and bearing capacity needs much more researches.This paper is financially supported by the National Natural Science Foundation of China(Nos.51574139,Nos.51274079)and the National Natural Science Foundation of Hebei province(Nos.E2015208089).Experiment,numerical simulation and theoretical analysis methods are used to investigate the installation process of dynamically embedded circular plate anchor.First,the penetration test device of dynamically embedded circular plate anchor was made.45 groups of indoor penetration experiments were carried out in ordinary clay and kaolin clay.Based on the principle of conservation of energy,a formula to calculate the penetration depth of dynamically embedded circular plate anchor is presented.A small strain finite element model considering circular plate-soil interaction in saturated clays is set up in ABAQUS software.The ultimate bearing capacity under combined normal,sliding and rotational forces is calculated.Then the yield surface of the dynamically embedded circular plate anchor is fitted.Macro-element method is employed to research the effects of the offset ratio and mud surface angle on the motion properties of keying process of the dynamically embedded circular plate anchor.Our main conclusions are:(1)With impact velocity on the mud surface increasing,the penetration depth of DEPLA increases.(2)With the soil strength increasing,the penetration depth of DEPLA decreases.(3)The penetration depth prediction formula in this paper can better predict the penetration depth of DEPLA.(4)The uniaxial normal,sliding and rotational capacity coefficient of the DEPLA in saturated soil are 12.54,6.83 and 1.47,respectively.The parameters of the yield surface of V-H-M space are fitted: q=4.21,n=2.23,m=6.05,p=1.18.The ultimate yield surface in this paper is different with that of Suction embedded plate anchor.(5)With the offset ratio increasing,the plate anchor embedment loss decreases,and the ultimate rotational angle rise up.Besides the padeye tension coefficient decreases.(6)With the mud surface angle increasing,the embedment loss of DEPLA increases,and the ultimate rotational angle increases.Besides the padeye tension coefficient also decreases.