Analysis of the Mechanical Properties of Central Columns in the Subway Station in Response to Groundwater Level Rise

Abstract Shallow underground excavation techniques are widely employed in urban subway construction, and the pile–beam–arch (PBA) method is especially prevalent in subway stations’ construction. This method is primarily designed to address the challenges posed by complex geological conditions, dense underground utilities and the proximity of existing structures encountered during the comprehensive development process of urban subterranean environments. This research focuses on the Workers’ Stadium Station of Beijing Metro Line 17, utilizing MIDAS GTS NX computational simulation software to simulate the stratigraphic structure and construction processes associated with the station. A comparative analysis is conducted between the numerical simulation results and the corresponding field-measured data. By fitting the numerical simulation results and field-measured data with a Gaussian function, the coefficient of determination ( R 2 ) is determined to be 0.9723. This indicates an excellent agreement between the axial forces sustained by the CFST column in the model and the field-measured data across various excavation stages of the PBA method. This suggests that the numerical modeling effectively reflects the impact of actual construction activities on the CFST columns. Additionally, building upon this model and integrating principles from elastic mechanics theory, the paper investigates the impact of rising groundwater levels on the central column of the station during its operational phase. The analysis reveals that as the groundwater levels rise, both the central column’s axial force and axial displacement exhibit a gradual upward trend, with the rate of increase initially rising before subsequently declining. Notably, when the groundwater level reaches the top slab of the station, both parameters attain their maximum values. This research contributes to understanding the implications of groundwater level fluctuations on the stability of subway stations and offers recommendations for the ongoing operation of such facilities.