海洋工程钢结构不规则防沉板基础承载力数值模拟

Numerical Simulation of Bearing Capacity for Irregular Mudmat Foundation of Offshore Structures

防沉板基础是海洋工程结构物中常用的浅基础形式,由于结构功能布置需要可能会导致其具有不规则的形状,同时海洋结构物的土壤条件和载荷条件较为复杂,要求防沉板基础具备可靠的承载能力。针对某海洋平台导管架结构的不规则防沉板基础,采用浅层土壤参数根据规范中推荐的理论公式以及面积和惯性矩等效的方法得到承载力;结合深层土壤条件,采用有限元方法和用户子程序对不同空间载荷作用下的极限承载力进行数值模拟。通过两种方法分析并验证了防沉板基础的承载力,结果表明:不规则形状的防沉板基础承载力计算可采用面积和惯性矩等效方法等效为长方形基础,浅层深度范围以内的土壤采用线性变化的承载力计算公式,与三维空间载荷作用下的有限元模型分析结果基本吻合。

Mudmat foundation is a common shallow foundation form in offshore structures.Due to the need of structural function arrangement,it may have irregular shape.At the same time,the soil conditions and load conditions of offshore structures are relatively complex,so the mudmat foundation is required to have reliable bearing capacity.For the irregular mudmat foundation of an offshore platform′s casing structure,the theoretical formula recommended in the code and the equivalent method of area and moment of inertia were used to obtain the bearing capacity by using the shallow soil parameters.Combined with deep soil conditions,finite element method and user subroutine are used to simulate the ultimate bearing capacity under different spatial loads.The bearing capacity of mudmat foundation was analyzed and verified by two methods.The results show that the bearing capacity of the irregular mudmat foundation can be equivalent to the rectangular foundation by using the equivalent method of area and moment of inertia,and the bearing capacity of the soil within the shallow depth can be calculated by using the linear variation formula,which is basically consistent with the finite element model analysis results under the action of three-dimensional space load.