The Study Of Boundary Condition On The Structure Analysis Of Offshore Platform With Positive Pressure Spouted And Strengthened Pile Foundation

The technical study for the design of offshore platform with positive pressurespouted and strengthened pile foundation is one of the principle contents for thenational 863 oceanology project. This kind of platform is a new type of offshoreproduction platform, which meets the requirements of bearing capability and overallstability by means of strengthened pile foundation. The platform is to be located onsoft ground base with advantages of simple structure, easy prefabrication, short-terminstallation, strengthened pile foundation and strong bearing capability. Hence, thestudy, which is quite important for oceanic resources exploitation, puts forward a newapproach to deal with the ground base. The lower cost of the platform make theexploitation of the marginal oil fields with fewer benefits possible. Therefore, in caseof increasing lack of oil resources, the study of this type of platform is of greatsignificance. The study to structural analysis for offshore platform with positive pressurespouted and strengthened pile foundation is developed in this paper. On the bases ofthe analyses for structure model and pile-soil interaction of the jacket platform, asimplification method of foundation boundary condition for this type of platform issuggested, according to the characteristics of the strengthened pile foundation. Thenonlinear finite element method is adopted to analyze the interaction between the pileand soil, which provides a completely new way to simplify the foundation boundarycondition for this type of platform. The relationships of the loads and their consequentdisplacements are transformed to linear or nonlinear spring elements as the foundationboundary condition that is to be applied in nonlinear static structural analysis usingANSYS program for the platform. The outcomes of the structural analysis indicatesthat the simplification method of foundation boundary condition is correct andfeasible, that the application of the spring boundary condition is predominant, and thatthe new method to deal with the foundation boundary condition for this type ofplatform is of remarkable theoreticalsignificance and applied value.