非均质软基上桶形基础承载性能有限元分析

作为海洋平台的基础部分,桶形基础不仅承受海洋平台结构及自身重量等竖向荷载的长期作用,而且往往还遭受波浪等所产生的水平荷载及力矩等其它荷载分量的作用。因此,确定软基上桶形基础在竖向荷载（V）、水平荷载（H）和力矩（M）等共同作用下的承载特性,建立其在复合加载模式下的破坏包络面,并进而依此评价海洋平台基础及地基的稳定性,是桶形基础设计与施工中的关键问题。在大型通用有限元分析软件ABAQUS平台上,采用基于Mises屈服准则的完全弹塑性本构模型,对横观各向异性软基上桶形基础的承载性能进行了三维弹塑性数值分析,探讨了软黏土不排水抗剪强度的各向异性对单个荷载和复合加载作用下桶形基础承载性能的影响。

FEM Analysis of Bearing Capacity of Bucket Foundation in the Cross-anisotropic Soft Soil

Bucket foundation is a new-type offshore foundation applicable especially for marginal field oil extraction,which is usually subjected to the simultaneous actions of both gravity and other environmental loads.Gravity loads act vertically while environmental loads induced by wave,wind and current are imposed laterally with both horizontal load and moment on the foundation.The responses of suction caisson foundation subjected to such a type of combined loads are therefore of great importance for the design and construction of offshore foundation.Three dimensional finite element numerical analyses are performed by using the general-purpose FEM package ABAQUS/Standard,in which the soil is assumed to obey the Mises＇s yield criterion.Both the stability or failure envelopes and collapse and working mechanism of suction bucket foundation founded in the cross-anisotropic soil strata under undrained conditions subjected to monotonic loading or combined loading are discussed.