Research On Ultimate Bearing Capacity Of Jack-up Platform Structure

In today’s rapid economic development,petroleum resources,as the blood of modern industry,have become an important constraint on the rapid and stable development of my country’s economy.With the increasing depletion of domestic onshore oil resources and the increasing difficulty of development,the future growth of oil production capacity will mainly come from the exploration and exploitation of offshore oil resources.As the main form of offshore oil exploration platform,jack-up drilling platform will be an important research aspect in the development of my country’s offshore oil resource development technology.The jack-up drilling platform has a variety of different operating conditions during use: moving,placing and lifting,inserting and pulling,preloading,standing(drilling,survival).The safety performance of the platform under various operating conditions relates to the smooth progress of the drilling operation and the personal safety of the operators.Therefore,it is necessary to conduct in-depth research on the structural safety,failure mechanism,failure mode and ultimate bearing capacity of the jack-up platform under the test of extreme conditions.This paper focuses on the core issues of the non-linear finite element analysis of the jack-up platform structure,the ultimate bearing capacity and failure mode of the jackup platform under the standing condition of the horizontal extreme environmental load and the main hull structure under the uneven settlement of the pile legs.The bearing capacity and failure mechanism of the steel are studied and analyzed.First,in order to study the ultimate bearing capacity of the jack-up platform against horizontal environmental loads in the standing state,a simplified model of the space frame of a 300 ft jack-up drilling platform is established in this paper,and environmental loads with different return periods calculated based on the threeparameter Weibull extreme value distribution are applied to the platform step by step.The non-linear static pushover analysis method is used to study the ultimate bearing capacity of the platform.The effects of the simplified methods of the hinged support and the elastic foundation on the ultimate bearing capacity and the failure mode of the pile leg structure are compared and analyzed.The ultimate bearing capacity of the platform is analyzed under a variety of environmental load incident directions,and the ultimate environmental load bearing capacity evaluation method of the platform based on the return period of the environmental load as the standard is proposed.Next,for the nonlinear response of the hull structure under uneven settlement of the pile legs,a large detailed finite element model of the main hull of the jack-up platform and the fixed pile structure is established in this paper.First,the structural strength analysis of the hull structure under pre-compression conditions is carried out to verify the correctness of the model.Then,referring to the Pushover method,the ultimate bearing capacity analysis of the hull structure under the pile leg settlement condition of the platform is carried out,and the failure path and potential weak links of the hull structure are studied.The research content of this paper provides certain reference and help for the structural safety assessment and improvement design of the jack-up platform.