Discrete Element Modeling of Railway Ballast Toward Improved Tamping Practices

The development of Discrete Element Model (DEM) of railway ballast for the purpose of studying the behavior of ballast particles during tamping is addressed in a simulation study. The research aims at optimizing the railroad tamping operation. A comprehensive literature review of applicability of DEM techniques in modeling the behavior of railway ballast has been conducted. The feasibility of DEM methods in studying the fundamental mechanisms that dictate the outcome of railroad tamping process has been analyzed. Using a DEM-based commercial software, a simulation model of the dynamics of railway ballasts during tamping has been developed and validated. The selection and calibration of ballast parameters, such as inter-particle contact force laws, ballast material properties, and selection of particle shape in the model have been evaluated in detail. Finally, a complete tamping simulation model has been constructed with high degree of adjustability to allow control of all process parameters for achieving realistic output. An analysis of the modeling results shows that DEM is a highly valuable tool for studying railroad tamping operation. It has the capability to provide crucial and unprecedented insights into the process, facilitating not only the optimization of current tamping practices, but also the development of novel methods for achieving sustainable improvements in track stability after tamping in the future. Different ways of modeling particle shapes have been evaluated and it has been shown that while using spheres to represent irregular ballast particles in DEM provides large gains in computational efficiency, they cannot capture all properties of irregularly-shaped particles. Additionally, the results indicate that the model is able to accurately predict properties of granular assemblies of the railway ballast in different test cases. The half-track model that has been developed thus far can be extended in future studies for evaluating rail track settlement and stability, optimization of tamping process, and performance of different ballast gradations.

Language

• English

Project

• Status: Active
• Funding: $180000
• Contract Numbers:

  69A3551747132

• Sponsor Organizations:

  Office of the Assistant Secretary for Research and Technology

  University Transportation Centers Program
  Department of Transportation
  Washington, DC  United States  20590
• Managing Organizations:

  Virginia Polytechnic Institute and State University, Blacksburg

  Virginia Tech Transportation Institute
  3500 Transportation Research Plaza
  Blacksburg, VA  United States  24061
• Project Managers:

  Ahmedian, Mehdi

• Performing Organizations:

  Virginia Polytechnic Institute and State University, Blacksburg

  Virginia Tech Transportation Institute
  3500 Transportation Research Plaza
  Blacksburg, VA  United States  24061
• Principal Investigators:

  Ahmedian, Mehdi

• Start Date: 20180101
• Expected Completion Date: 20231231
• Actual Completion Date: 0
• USDOT Program: University Transportation Centers Program

Subject/Index Terms

• TRT Terms: Ballast (Railroads); Calibration; Feasibility analysis; Simulation; Tamping; Validation
• Subject Areas: Maintenance and Preservation; Railroads;

Filing Info

• Accession Number: 01703226
• Record Type: Research project
• Source Agency: University Transportation Center on Improving Rail Transportation Infrastructure Sustainability and Durability
• Contract Numbers: 69A3551747132
• Files: UTC, RIP
• Created Date: Apr 27 2019 7:27PM