Enhancing railway track stiffness and sustainability through flowable dredged soil backfill

Abstract

This study investigates flowable dredged soil backfill using air-foam technology and simulates a bridge approach structure under high-speed train loads. A comparison between conventional cement-treated soil (CTB) and innovative flowable dredged soil backfill solutions reveals crucial findings: Resilient modulus tests highlight the significant impact of cement and air foam, favoring mixtures with over 210 kg/m3 cement content and less than 10% air-foam, resulting in a resilient modulus of 354 MPa. Finite Element Method (FEM) simulations show CTB compliance with k1/k2 standards for all track options and the effectiveness of lightweight soil, especially Silty Soil (SM), in preventing critical k1/k2 increases. The lightweight soil exhibits superior performance through FEM analysis, settling only 3 mm after 800,000 cyclic train loads compared to nearly 5 mm in conventional CTB systems. This confirms the feasibility of lightweight dredged soil backfill in strengthening weak bridge approach foundations, enhancing railway track infrastructure sustainability and performance.