Numerical Modeling Of Extraction Of Jack-up Drilling Platform

Offshore drilling platform is one of the most important equipment in the offshore oil and gas development,which plays an important role in the offshore oil and gas exploration and development.The design and construction of offshore drilling platform,is a symbol of national scientific research and comprehensive strength,and the large capital investment,high technical diffiSulty,is the national scientific research direction have been the foSus of investment.For jack up drilling platform,it is very diffiSult to pull out of a pile when the pile penetrate a deeper embedment,and sometimes it will appear the main structure damaged when the process of extraction,which causes a huge economic losses.At the same tme,due to the complexity of the marine environment,it is inevitable to be subjected to wave loading.Therefore,it is very important to analyze the extraction of pile and study the pile and soil dynamic response under cyclic wave load.This paper uses Finite element software ABAQUS to study the extraction of pile.When the wave load is not considered,parameters method was used to simulate the extraction response of pile,which include the elastic modulus of soil,the soil undrained strength,pile foundation embedment,the diameter of spudcan.Research indicts,with the elastic modulus E increases,extraction resistance increases.When the elastic modulus E>40000Su,extraction resistance almost stay constant.With the soil undrained strength increases,the displacement is needed more to reach peak extraction resistance.With the increase of the embedment,the uplift bearing capacity of the pile is obviously increased,and the stress distribution of the soil around the pile foundation is gradually expanded.At the same time,the distribution of the stress and the displacement of the soil around the pile under wave loading is simulated,and analyze the reduction of the strength of the soil and the weakening of the bearing capacity.Based on the above analysis,the conclusion is obtained.Under the action of wave load,with the increase of the horizontal distance of the pile foundation,the influence of the wave cycle load on the soil is more and more small.In the vertical direction,the seabed soil surface is influenced by wave cyclic loading,the pile foundation with the increase of buried depth,the vertical displacement of the soil around the pile gradually decreases by wave cyclic loading disturbance is more and more small.The additional stress of soil is gradually reduced,and the horizontal stress S11 is small when the distance from the sea bed surface is more than 14 m,and the can be ignored approximately.Combined with the reduction of the soil strength,calSulating the capacity under the wave load,the vertical bearing capacity reduction rate was 6.50%,the horizontal bearing capacity reduction rate was 26.79%,the pullout capacity reduction rate was 7.31%.