地基边界条件对自升式平台桩腿承载性能的影响

针对深水自升式平台桩靴边界条件模拟问题，以某300英尺(1英尺=0.304 8 m)自升式平台为例，采用ANSYS有限元软件进行静力分析和极限承载力分析，对比常规铰支和弹性基础约束条件对自升式平台桩腿强度的影响，进一步探究不同桩-土边界条件对桩腿极限承载力和失效模式的影响。结果表明：弹性基础约束方式可有效降低重力二阶效应(p-Delta效应)的影响程度，使相应工况下的有效应力明显减小，在这种约束方式下计算得到的桩腿刚度更大且桩腿会率先进入塑性阶段；铰支约束过于保守；在2种边界条件下桩腿的失效模式也有较大差异。研究结果可为自升式平台的设计提供参考。

Influence of Foundation Boundary Conditions on Bearing Capacity of Jack-up Platform Legs

Aiming at the problem of boundary condition simulation of pile shoe of deep-water jack-up platform, taken a 300 ft (1 ft=0.304 8 m) jack-up platform as an example, the finite element software ANSYS is used for the static analysis and ultimate bearing capacity analysis, the influence of the conventional hinged support and elastic foundation constraints on the pile leg strength of the jack-up platform is compared, and the influence of different pile-soil boundary conditions on the ultimate bearing capacity and failure mode of the pile leg is further explored. The results show that: the elastic foundation constraint can effectively reduce the influence of p-Delta effect and significantly reduce the effective stress under corresponding working conditions, the stiffness of the pile leg calculated under this constraint method is greater, and the pile leg will enter the plastic stage first; the hinged support constraint is too conservative; the failure modes of the pile leg under the two boundary conditions are also quite different. The research can provide reference for the design of the jack-up platform.