Structural Strength Analysis Of Deepwater Jacket Platform Under Harsh Wind And Waves

In recent years,the coastal typhoons is becoming more and more frequent.According to statistics,the first 10 months of 2016,the coastal area has experienced 22 typhoons.Typhoons have caused serious damage to coastal areas.For deepwater jacket platform,which is fixed in the seabed buildings.If facing such a typhoon,it can not be like a movable platform which can be evacuated in time.If Jacket platform collapsed in a strong typhoon,it will bring great threat to people who exploiting offshore oil and gas,and bring immeasurable losses.So it is necessary for a variety of harsh environments deepwater jacket platform structural strength of the analysis and study.The main contents of this paper are as follows:1.Two kinds of restraint methods are adopted to establish platform model,namely equivalent pile method and non-linear spring method.The equivalent pile method is fixed 6times below the mud surface,and nonlinear spring method is based on P-y curve theory.The soils with different depths are regarded as nonlinear springs,which simulate the pile-soil interaction.The ultimate bearing capacity of the platform is analyzed by using the nonlinear static pushover analysis method.The bearing capacity of the platform is studied in the three main directions,and the difference of the ultimate bearing capacity between different restraint methods is compared and analyzed.Then,considering the change of the ultimate bearing capacity after the key bracing failure in the platform,the reserve strength of the platform in the direction of the platform and the bracing failure is calculated and studied.2.The modal of the platform of the two constraints is analyzed and the differences are analyzed.The first two natural frequencies of the platform are extracted,and the damping coefficient of the platform is calculated.The transient dynamic analysis of the platform is carried out to compare the displacement,velocity and acceleration response of the vertexes under the two constraints.Then,considering the dynamic amplification coefficient,the static analysis of the platform is carried out,and the displacement of the platform under static analysis is calculated.Then,the maximum displacement in the dynamic response is divided by the static displacement,and the dynamic amplification coefficients are obtained.Different directions and different constraints under the dynamic amplification factor of the difference,to find out the law of change.Finally,the displacement distribution and bending moment distribution of the skirt piles along the depth of the soil are extracted for thenonlinear spring-restrained model,and the difference between the shallow soil and the deep soil is analyzed.The displacement of each leg in the skirt pile is analyzed,The distribution of bending moment with depth.3.For the storm surge produced by the impact of water,resulting in the platform deck elevation to reduce the phenomenon of surfacing on the deck,simplified version of the three linear wave model is used.The influence of wave load on the displacement,velocity and acceleration of the platform is studied.The working conditions of different wave depth and different wave height are compared and analyzed,and the response law under different wave height is studied.For the waves on the raid load,the main study under the pound load,the deck of the stress changes and the vertical displacement of the plate changes.