Journal Article

Evolution Analysis of Soil-Arching Effect and Calculation of Pile–Soil Stress Ratio of Bidirectionally Reinforced Composite Foundation

Zhang, Xinyuan, Ma, Chuanyi, Li, Chao, Fan, Wei, Sun, Yafeng

2025

Overview

In recent years, bidirectionally reinforced composite foundations have been widely used in highway, railway, and bridge engineering with notable results. The key mechanism is the soil-arching effect, which arises from the self-adjustment of the soil and directly affects the bearing capacity of the foundation. In this study, numerical simulation was employed to analyze the vertical stress in the subgrade soil and the transfer of particle contact forces from the macro and micro perspectives. The existence of the soil-arching effect was confirmed, and its variation under loading was revealed. To quantify the degree of the soil-arching effect, the stress transfer efficiency of the soil between piles was introduced. Subsequently, a bidimensional theoretical model was established based on the coordinated deformation among the embankment, the horizontally reinforced cushion, the vertical piles, and the soil. In this model, the combined effects of the embankment soil-arching, the reinforcement of cushion net, and the stress diffusion were incorporated. A method for the calculating of the pile–soil stress ratio of bidirectionally reinforced composite foundation was proposed, and the influence of various factors on this ratio was explored. The results indicate that the soil-arching effect can be divided into three stages according to the height of the subgrade fill: no-arch stage, transition stage, and soil-arching stage. Reducing pile spacing or increasing cushion thickness can improve the stress transfer efficiency. When the pile length is appropriate, the stress in the foundation soil at 0.55 times the pile depth was contoured, enhancing stability. The pile–soil stress ratio decreases with the increase in filling weight and pile spacing, increased first and then decreased with increasing internal friction angle of filling materials, and increased with the increasing height of embankment, the number of geogrid layers, and the cohesion of filling materials.

• Publisher: MDPI AG
• Subject: Analysis / Bearing capacity / bidirectional reinforced composite foundation / Bridges / Contact force / Contact stresses / Cushions / Deformation / Embankments / Fillers / Height / influencing factors / Internal friction / Investigations / Load / macro-micro analysis / Mathematical models / Numerical analysis / pile–soil stress ratio / sensitivity analysis / Shear strength / Simulation / Simulation methods / Soil analysis / Soil stresses / soil-arching effect / Stress ratio / Stress transfer / Subgrades