考虑土-结相互作用的大型结构高效地震分析方法

EFFICIENT SEISMIC ANALYSIS METHOD OF LARGE STRUCTURES CONSIDERING SOIL-STRUCTURE INTERACTION

  • 摘要: 在对大型工程结构进行地震反应分析时土-结构相互作用通常不可忽略,然而,结构本身巨大的体量及考虑土-结构相互作用后引入的大范围土域模型导致计算规模通常十分庞大,由此引起的计算效率低下问题已成为制约此类结构性能分析的关键因素。该文提出一种新型土-结相互作用分析方法,并基于此实现了大型结构考虑土-结构相互作用的高效地震反应分析,建立不同接触状态下的单元法向和剪切相对位移分解方法;采用三维无厚度Goodman接触面单元格式对土与结构的接触行为进行描述,并通过插值方法对单元非线性变形进行描述,推导出隔离非线性的接触面单元控制方程;在此基础上,建立了大型工程结构考虑土-结构相互作用的整体式计算模型和高效地震反应分析方法。由于该文方法在每次迭代求解过程采用Woodbury公式计算结构响应,其仅需对一个规模极小的局部非线性矩阵进行迭代更新,避免了传统方法所需的结构大规模整体刚度矩阵实时更新分解,因而能够大幅度提高结构地震反应分析效率,数值算例验证了该文方法的有效性及高效性。

     

    Abstract: In the seismic response analysis of large engineering structures, the soil-structure interaction can not be ignored. However, the calculation scale is usually very large due to the huge volume of the structure itself and the large scale soil model introduced after considering the soil-structure interaction. The low calculation efficiency has become the key factor restricting the performance analysis of such structures. A new soil-structure interaction analysis method is proposed, based on which an efficient seismic response analysis of large scale structures considering soil-structure interaction is realized. The decomposition method of element normal and shear relative displacement under different initial contact states is established. The contact behavior between soil and structure is described by using the three-dimensional zero thickness Goodman interface element. The inelastic deformation of the element is described by the interpolation method, and the control equation of the interface element with Inelasticity-separated method is derived. On this basis, a global calculation model considering soil-structure interaction and an efficient seismic response analysis method of large-scale engineering structures are established. Since the Woodbury formula is used to calculate the structural response in each iterative solution process, it is only necessary to iterate and update a small dimension local inelastic matrix. During the iteration process, the real-time updating and factorization of the large-scale global stiffness matrix required by the classical finite-element is avoided, which can greatly improve the efficiency of structural seismic response analysis. The effectiveness and efficiency of the proposed method is verified using numerical examples.

     

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