复合加载下桶形基础循环承载性能数值分析  

Numerical analysis of cyclic bearing capacity of bucket foundation under combined loading mode

作　　者：栾茂田[1] 武科[1] 范庆来[1] 王志云[1] 赵少飞[2] 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室 [2]华北科技学院建筑工程系,北京065201

出　　处：《海洋工程》2007年第3期88-94,共7页The Ocean Engineering

基　　金：国家自然科学基金重点基金资助项目(50639010);国家自然科学基金资助项目(5079006);教育部跨世纪优秀人才培养计划研究基金资助项目(教技函[1998]2号)

摘　　要：作为一种新型基础形式,吸力式桶形基础除了承受海洋平台结构及自身重量等竖向荷载的长期作用之外,往往还遭受波浪等所产生的水平荷载及其力矩等其它荷载分量的瞬时或循环作用。对复合加载模式下软土地基中桶形基础及其结构的循环承载性能尚缺乏合理的分析与计算方法。应用Andersen等对重力式平台基础及地基所建议的分析方法,基于软黏土的循环强度概念,在大型通用有限元分析软件ABAQUS平台上,通过二次开发,将软土的循环强度与Mises屈服准则结合,针对吸力式桶形基础,基于拟静力分析建立了复合加载模式下循环承载性能的计算模型,并与复合加载作用下极限承载性能进行了对比。由此表明,与极限承载力相比,桶形基础的循环承载力显著降低。As one of new types of offshore foundations, the suction bucket foundation not only is subjected to vertical loading caused by structural weight and other vertical dead or dynamic loads, but also sustains horizontal load and moment due to wind-or wave-induced loading. It is characterized that these load components are varied in magnitude and alternating in direction with time cychcally or irregularly. However, studies on cyclic beating capacity of suction bucket foundation under combined loading mode are not sufficient to work out a reasonable analysis and computational procedure. In this paper, based on the concept of cyclic shear strength of soil, a quasi-static finite element method for assessing cyclic bearing capacity of offshore foundations or structures is developed by using the method proposed by Andersen. Then the proposed method is numerically implemented in the framework of the general-purpose FEM software package ABAQUS. In the method, cyclic strength of the soft soil and Mises yield criterion are combined together to numerically evaluate cyclic bearing capacity under combined loading by ABAQUS. A number of three-dimensional nonlinear FEM computations for cyclic bearing capacity are conducted and then compared with ultimate bearing capacity. The numerical results computed by the proposed method indicate that cyclic bearing capacity is reduced noticeably due to the cyclic softening effect induced by wave loading with respect to ultimate bearing capacity.

关 键 词：桶形基础 循环承载力 有限元 复合加载 

分 类 号：TU470[建筑科学—结构工程]