This paper presents an efficient approach for the modal analysis of coupled soil-structure systems, for which the dynamic response is strongly influenced by the embedment in the soil. The methodology is based on a finite element-perfectly matched layer model that allows for the derivation of frequency-independent system matrices and the computation of the modal properties of the coupled system. This is achieved by solving a nonlinear eigenproblem using a Compact Rational Krylov (CoRK) eigensolver. A procedure is developed to sort the computed eigenpairs, filter out the spurious modes of the system which are related to the near-field and truncated far-field soil subdomains and select the physical structural modes of system. The proposed method can be used in the dynamic assessment and structural identification of strongly coupled soil-structure systems such as fully or partially buried structures and allows for the interpretation of experimentally identified modal properties of these systems, especially in the presence of highly damped or closely spaced coupled modes. The applicability and the scalability of the proposed approach for 2D and 3D problems is demonstrated in two case studies.

本文为耦合土-结构系统的模态分析提供了一种有效的方法，其动态响应受土壤中嵌入物的强烈影响。该方法基于有限元完美匹配的层模型，该模型允许推导与频率无关的系统矩阵，并计算耦合系统的模态特性。这是通过使用Compact Rational Krylov（CoRK）特征求解器解决非线性特征问题来实现的。开发了一种程序来对计算出的特征对进行分类，过滤掉与近场和截断远场土壤子域相关的系统的虚假模式，并选择系统的物理结构模式。所提出的方法可以用于强耦合土壤结构系统（例如完全或部分埋藏的结构）的动态评估和结构识别，并且可以解释这些系统的实验识别模态特性，尤其是在存在高阻尼或紧密耦合的情况下。间隔耦合模式。在两个案例研究中证明了该方法在2D和3D问题中的适用性和可扩展性。