A Study On Bearing Capacity Behaviour Of Bucket Foundations Under Combined Loading In Soft Clay

Bucket foundation is a new technology of ocean platform,which has the broad application prospect in the offshore marginal oilfield development. The capability of horizontal, vertical and under bending moment of the bucket foundation which sitting on offshore shoal area soft clay deeply influence the application and promotion of the project. This paper conducts research on the capacity of bucket foundation, which is applied in soft clay. The main research work has the following several aspects:According to finite element model calculations, analysising the failure mode of foundation subjected to vertical load, it is clarified that Hansen and Vesic Foundation bearing capacity relationship can describe the vertical bearing capacity characteristics of single bucket and four fuckets foundation clearly.Using Engel assumption, in accordance with Three-dimensional space problems, the Formula of horizontal eccentric bearing capacity is established by the limit equilibrium method. Base on the Finite Element Analysis results of horizontal eccentric bearing capacity calculation and introducing vertical load influence coefficient, established the complex bearing capacity calculation method. Base on the Finite Element Model and results of horizontal eccentric bearing capacity calculation, established the relationship of complex bearing capacity between single bucket and four buckets. Four buckets platform complex bearing capacity calculation method was firstly proposed.Based on cyclic triaxial testing and the concept of soft clay cyclic strength which was proposed by Anderson, quasi-static three-dimensional elastic-plastic finite element model subjected to complex load was established. Take 1000 cycle for example, showed the horizontal eccentric circulating bearing capacity characteristics of bucket foundation. Considering the impact of the vertical bearing capacity to the horizontal eccentric circulating bearing capacity, proposed complex circulating bearing capacity calculation method. Base on the finite element model and results of complex circulating bearing capacity calculation, established the relationship of complex circulating bearing capacity between single bucket and four buckets. Four buckets platform complex circulating bearing capacity calculation method was firstly proposed.Conducted indoor four-bucket foundation platform model test and validated the results of finite element anlysis and formula calculations, Model tests of four-bucke foundation in the stratum are conducted to research its bearing capacity under different vertical static and horizontal eccentric cyclic loads.According to model test condition, the simulation calculations are performed by using the cyclic strength relationship of the stratum and FEM. Calculating results are in agreement with test results, which show that the horizontal eccentric cyclic bearing capacity of the bucket foundation in the soft clay can be evaluated by using FEM based on the cyclic strength relationship and calculation method in the article.By the method proposed, calculated the bearing capacity of a bucket foundation platform which is planned to use in offshore shallow water, the results showed that the bearing capacities of foundation meet the requirements...