Application and Parameter Matching of a Novel Pipe-Roof-Concrete Slab Method in Metro Stations

The pipe-roof method is an increasingly popular pre-construction support system for underground space development. However, conventional pipe-roof systems suffer from low bearing capacity and complex construction procedures, limiting their application in ultra-shallow-buried large-span metro stations. To address these limitations, this study proposes an innovative adaptation termed the pipe-roof-concrete slab (PRCS) method. Based on the Shenyang Metro Line 3 Heping South Street Station in China, a three-dimensional finite difference model was developed through refined modeling and validated against field measurements. The results reveal that surface settlement follows a quadratic function relationship with pipe-roof stiffness and roof slab modulus, and a linear relationship with slab spacing and thickness. Increasing pipe-roof stiffness from 0.5EI to 2.5EI reduces maximum settlement by 41.40%, while increasing slab thickness from 400 mm to 1,000 mm reduces settlement by 35.95%. A multiple linear regression model was established to quantify the matching relationships between parameters, achieving an adjusted R² of 0.886. These quantitative relationships provide a theoretical basis for understanding the parameter interactions and optimizing the structural design of PRCS systems. Based on these findings, practical guidance is provided for the rational selection of structural parameters to meet different settlement control standards in similar underground engineering projects.