Undrained capacity of foldable mudmats under combined V-M loading
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摘要: 可折叠防沉板可有效解决单块防沉板因面积过大而导致的巨额安装施工费用问题,是深海油气资源开采生产系统中的新型基础结构。在服役期间承受竖向、水平、弯矩及扭矩等荷载的复合作用,其承载力不仅与防沉板的尺寸和地基土强度及其分布特性有关,而且还与可折叠防沉板两翼间距有关,导致不能直接采用传统的防沉板承载力计算方法进行计算。采用有限元方法对可折叠防沉板的不排水承载力进行三维数值模拟,计算得到竖向V、弯矩M加载条件下及组合V-M加载条件下的极限承载力,系统分析了单向(V,M)及组合(V-M)加载条件下的地基破坏模式,提出了单向承载力计算方法并建立了组合加载条件下的破坏包络线,进而提出了复合加载条件下的承载力计算方法,为可折叠防沉板的承载力设计提供依据。Abstract: The foldable mudmat rigidly connected by two adjacent foundations is a new type of infrastructure used in subsea production systems. During service, the stress state is a multi-degree of freedom-combined loading mode, and the bearing characteristics are affected by the foundation spacing and soil strength heterogeneity of the seabed. The undrained capacity of the foldable mudmats is investigated in three-dimensional numerical analysis by means of the finite element software ABAQUS, the results are presented in terms of the ultimate limit states under pure vertical or moment loading, and the failure envelopes under combined V-M loading, and the influence of the foundation spacing and soil strength heterogeneity of the foundation soil are systematically analyzed. Based on the finite element calculated results combined with failure mode analysis, the formulas for the vertical bearing capacity, moment capacity and V-M failure envelope of the foldable mudmats are proposed to provide evidence for stability analysis of the foldable mudmats.
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Keywords:
- foldable mudmat /
- combined loading /
- failure envelope /
- finite element analysis /
- undrained capacity
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表 1 参数
κ ,su0,k取值Table 1 Values of parameters
κ ,su0,kκ k/(kPa·m-1) su0/kPa 1 1.0 5.00 2 1.0 2.50 5 1.0 1.00 10 1.0 0.50 20 1.0 0.25 -
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