Dynamic Earth Pressure Model Tests of SPSC-AC Structure for Railway Slopes Under Simulated Train Loading

This paper investigates earth pressure and load transfer of a novel Surrounding Pile Soil Coupling–Anti-slide Chord (SPSC-AC) structure for railway slope reinforcement under dynamic train loading through physical model experiments. The study systematically analyzes the synergistic effects of the connecting beam rise-to-span ratio (f/L) and anchoring ratio (η) on the structural load redistribution mechanism and pile–soil interaction. The results show that the SPSC-AC structure forms a three-dimensional (3-D) soil arch via the curved connecting beams. The inter-row earth pressure follows a pattern of rear row > middle row > front row, while the earth pressure on corner piles exhibits a reverse increase owing to the soil arching effect. The rear pile thrust sharing ratio δ (0.58–0.68) and the pile–soil stress ratio n (1.16–1.37) are defined as two key performance parameters reflecting load distribution efficiency, and quantitative δ–f/L and δ–η relationships are established. The bending moment distribution along the pile body corresponds closely with the earth pressure pattern. Based on these results, the present study proposes optimal parameter ranges (f/L ∈ [1/4, 1/3] and η ∈ [5/11, 7/13]) along with recommendations for corner pile strengthening and differential stiffness design. These findings provide a theoretical basis for optimal anti-slide structure design.