Study On The Stability Of Suction Box-bucket Foundation For A Gravity Platform In Shallow Sea

In the development of oil and gas industry in Bohai Bay and adjacent marine area, the structure of the negative-pressure bucket foundation provides a new way for the construction of offshore platforms in soft soil region. It developed from the gravity platform with apron board base, which is a new style base and combines the features of raft foundation and pile foundation. Gravity bucket foundation base is applied more and more widely in recent years, and regarded as a new tank for a temporary storage of offshore platform. This paper incorporating the actual projects focuses on the study of the vertical bearing capacity of the negative bucket foundation, provides a reliable theoretical basis and accumulates experience for future design and construction.This article which is based on the model of caisson-bucket-integrated foundation, through the process of oil storage and discharge, determines the stability of the foundation soil. A series of theoretical analysis, simulating tests on model buckets and numerical simulation have been carried out. In addition, according with specific project requirements, we have analyzed caisson-bucket-integrated foundation, got the ultimate bearing capacity of the platform under alternating loads, and obtained the stability and deformation of the foundation under cyclic loading. Through static triaxial tests, the internal friction angle and cohesion of the foundation soil have been obtained. This paper pays more attention to the analyzing process of the foundation soil, carries out a systematic analysis of physical model test, determines the stability under alternating loads,. Applying Mohr-Coulomb strength theory and ultimate load theory, we analyzed and calculated the ultimate bearing capacity of foundation, Finally, we analyzed the relationship between various parameters.Based on Mohr-Coulomb shear strength theory, and on the three-dimensional numerical simulation, the ultimate vertical loads can be drawn in that the stress state and strain state can be certain. Finally, the P-S cures were drawn, which determines the foundation stability.Finally, analysis of the physical model, finite element models and the calculation results about the caisson-bucket-integrated foundation were taken, we obtained the advantages and disadvantages of each analogue. In the article, we research the stability of the caisson-bucket-integrated foundation for the first time, and establish the simplified model which can reflect the effect between the caisson-bucket-integrated bucket and foundation soil so as to provide theoretical and experimental basis for the feasibility of the operation of practical construction.