Mechanical Difference Analysis of Single-row and Double-row Side Piles in Stations by PBA Method Based on Model Test

Abstract

This study employs the pile-beam-arch (PBA) method to investigate the force-evolution law of micro-steel pipe piles during the excavation process, focusing on a Guangzhou metro-station project. Through laboratory model tests, we compared and analyzed the mechanical evolution laws of single-row and double-row side piles. Our findings revealed a significant soil arch effect in both single-row and double-row piles; with similar distribution patterns and peak-stress range. As soil excavation progresses, the soil arching effect shifts downward. Notably, the stress concentration in double-row piles is weaker than that in single-row piles, especially in the soil range of 0–50 mm after the piles. This is attributed to the looser soil between single-row piles, resulting in more evident stress release. The attenuation amplitude of the Y-direction stress of the double-row piles was considerably smaller than that of the single-row piles. The soil arching between the back-row piles in doublerow configurations exhibits shielding effects on the force of front-row piles, significantly weakening the soil pressure on them. This impact alters the force of the front-row piles, even causing the tip of the front-row piles to bend in reverse. The research results provide important insights for similar projects and can serve as a valuable reference.