Case Studies in Construction Materials (Jul 2024)
Mobilizing railway track stability with nonionic cement asphalt mortar for floating sleeper mitigation – 2D/3D numerical investigation and full-scale testing verification
Abstract
This study addresses the mitigation of the floating sleeper phenomenon in ballasted railway tracks through the implementation of Nonionic Cement Asphalt Mortar (CAM). Full-scale testing experiments evaluate track performance with and without CAM stabilization, revealing its efficacy in forming a robust membrane between ballast particles to reinforce the track-bed structure. Wheel load modeling, including static and dynamic, train movement modeling, roadbed pressure analysis, distribution of load, and track rigidity analysis. Life Cycle Cost Analysis (LCCA) establishes CAM's cost-effectiveness by significantly reducing settlement and ensuring long-term durability. Numerical simulations using ABAQUS demonstrate CAM's effectiveness in stabilizing deteriorated ballast. Furthermore, the simulations prove capable of detecting the floating sleeper phenomenon in the full-scale test bed, offering valuable insights into real-world applications. Both 2D and 3D modeling consistently show a more than 30% reduction in initial settlement and a 0.5 mm displacement in CAM-reinforced ballast compared to controls. Plastic displacement in new ballast is consistently 50% less in the initial 50,000 cycles, with ultimate plastic settlement reduced by 40%, indicating the robustness of CAM across different modeling dimensions. The dataset analysis identifies a floating sleeper issue, evidenced by pressure variations in deteriorated ballast. In the control and simulation sections, there is a pressure drop from 65 kPa to 28 kPa, while the reinforced section maintains stable pressures (50 kPa, 36.5 kPa, 10 kPa) with closely aligned predicted values. Despite pressure reduction in simulated zones, the dataset strongly supports concerns about the substantial pressure decrease due to the floating sleeper phenomenon. LCCA substantiates CAM's economic advantage, showcasing a 79.7% cost reduction over 60 years, endorsing CAM as a sustainable maintenance strategy. In conclusion, CAM stabilization effectively mitigates the floating sleeper effect, ensuring long-term track durability, and providing valuable contributions to sustainable railway infrastructure design and maintenance practices.
