Long-term mechanical behavior of load-shedding culverts on soft soil foundation

Abstract

Load-shedding culverts reduce the load on the structure by altering the transmission path of the backfill load above them. However, their long-term stress characteristics and load reduction efficacy on soft soil foundations remain uncertain. This study derives theoretical methods for calculating short-term and long-term earth pressures around the load-shedding culvert based on the equal settlement plane theory and compares these results with numerical simulations. The analysis reveals that, due to foundation soil consolidation and expanded polystyrene (EPS) creep, the vertical earth pressure at the culvert top slab decreases over time and stabilizes, with the earth pressure coefficient decreasing from 0.64 to 0.15. Stress concentration on the load-shedding blocks diminishes gradually, and the earth pressures acting on them approach the self-weight of the backfill. Lateral earth pressures at the mid-height of the culvert sidewalls increase over time and gradually stabilize, reaching an earth pressure coefficient of 1.04 after 50 years. The foundation contact pressure initially decreases before stabilizing, with the average earth pressure coefficient decreasing to 0.21 after 50 years. These findings provide a valuable reference for the design and long-term performance prediction of load-shedding culverts.