Study Of Structural Improvement Of Mudmat In Deep Sea Subsea System

Mudmat is an important form of foundation used in subsea system and has extensive application in the development of ocean engineering.Bearing capacity of foundation influences the range of mudmat application,and it is also related to the stability and safety of subsea system.Along with the progress of ocean development,human is now focus on the deep sea area inside of shallow water.The requirement of foundation bearing capacity improves a lot in situation of choosing mudmat as foundation of subsea production system.In this article,to solve the problem of insufficient bearing capacity of mudmat and broaden the use range,structural improvement is proposed.By using numerical simulation,mudmat-soil interaction model was built with finite element software ABAQUS.With balancing the soil in-situ stress,setting the master-slave contact,applying the gravity load and displacement constraint,comparative analysis was carried out with method Swipe to find out the differences among ultimate bearing capacity of different mudmats under combined loading.Uniaxial vertical bearing capacity and failure envelopes of V-H and H-M load space are also discussed in this paper.The calculation outputs show that whether the bottom structure exist or not,and form,arrangement and depth of the bottom structure of mudmat have a significant effect on load-displacement curves and failure envelopes.The simulation of injection process was involved in the article.By means of CEL,the analysis of penetration was carried out between different mudmats with various infrastructures to point out the resistance of soil and required external force.It is clearly that the heave of bottom soil is an important factor to hinder the injection process.The relationship between structural modifications and heave of soil must be considered cautiously.This analysis provides some references of installation process and penetration feasibility to a certain degree.Installation methods of subsea production system and mudmat was discussed in this article.In accord with injection analysis,these installation methods offer practical engineering basis for design,manufacture and installation of mudmat.Taking the analysis of bearing capacity and simulation of injection process into consideration.It is suggested that the problem of lacking of bearing capacity can be solved by structural improvement.Finally,this article provides a reference to enlarge the application fields of mudmat.