Abstract: The 2.5D finite element method is a frequency-domain method that offers advantages such as high computing efficiency and low memory consumption. Over the past two decades, continuous improvements have been made to this method, enabling it to accurately describe the dynamic response of railway subgrades by considering complex soil constitutive relationships and geometric characteristics. Through advancements in load input methods, modeling strategies, and wave absorption boundaries, the accuracy of the 2.5D finite element method has been steadily improved. The 2D interpolation method has also been employed to enhance computational efficiency for random dynamic responses of subgrades. As a result, the 2.5D finite element method has become a commonly used approach in the study of dynamic responses of railway subgrades. To provide a comprehensive understanding of the development of the 2.5D finite element method in researching the dynamic response of railway subgrades, this paper summarizes the current development status from various perspectives, including load input, subgrade system, response output, and improvements in calculation accuracy and efficiency. The paper also addresses bottleneck problems and proposes corresponding solutions. Based on these findings, further discussions and prospects are presented regarding the algorithm’s accuracy and efficiency, as well as the research objectives and content. This paper serves as a valuable reference for future research endeavors, offering insights into the advancements of the 2.5D finite element method in studying the dynamic response of railway subgrades.

Key words: 2.5D finite element method, railway subgrade, dynamic response, modeling, absorbing boundary, 2D interpolation