Analysis of the stress-strain state of a reinforced concrete collector considering soil-structure interaction

Abstract

The paper analyzes the stress-strain state (SSS) of a rectangular reinforced concrete collector, constructed during the development of the Syretsko-Pecherska metro line in Kyiv. The study aims to verify design solutions by performing duplicate calculations and comparing simplified engineering approaches with a comprehensive 2D model that accounts for the "soil-structure" interaction. Three calculation schemes were employed to evaluate the SSS: a continuum 2D model in "Midas GTS NX" software (considering the "soil-structure" system as a single unit) and simplified 2D/3D models in "Lira-SAPR" software using subgrade reaction coefficients. The study accounted for dead loads (soil weight, pavement) and live loads from vehicles ("NK-100", "qA15") across six load combinations. Significant discrepancies were found between the results of the refined and simplified models. Simplified methods were shown to lead to a substantial underestimation of forces in critical zones. Specifically, bending moments in the collector's top slab were 15–24% higher in the span and 4.5 times higher in the corner joints compared to simplified analytical results. This is because the continuum model accounts for the actual geometry of the joints and the complex mechanism of stress redistribution within the soil mass surrounding a rigid structure. The study confirms that simplified models based on an elastic foundation lead to incorrect distribution of internal forces along the frame perimeter. For high-precision calculations of deep-seated reinforced concrete collectors, numerical modeling in a continuum formulation is recommended to ensure the reliability of reinforcement solutions.