Abstract
Mud pumping in subgrade beds under ballastless tracks will deteriorate the dynamic performance of infrastructure under railway lines, reduce the smoothness of the railway lines, and seriously affect the comfort and safety of the trains. Due to their good mechanical properties, two-component polyurethane materials can be used for grouting to treat the fouling problems caused by ballastless track mud pumping. To develop a polyurethane formula suitable for the treatment of ballastless track mud pumping, we first performed indoor experiments to investigate the mechanical properties and gelation time of polyurethane elastomers synthesized with different raw material composition ratios, to determine an optimal composition ratio of the raw materials. Then, we conducted a dynamic field test to verify the remediation effect of the polyurethane material fabricated according to the design ratio. The results showed that polyurethane grouting material with the selected design ratios improved the contact characteristics between the surface layer of the subgrade bed and the base plate in the area, coordinating the dynamic response between the track structure and the subgrade bed. Thus, the obtained polyurethane grouting material could be used to renovate mud pumping areas of ballastless tracks with a good treatment effect.
Highlights
By the end of 2020, the total operating mileage of highspeed railways in China reached 39,000 km, with ballastless tracks being the main track structure type due to their excellent integrity, superior durability, and good strength properties
Mud pumping in subgrade beds under ballastless tracks will deteriorate the dynamic performance of infrastructure under railway lines, reduce the smoothness of the railway lines, and seriously affect the comfort and safety of the trains
Due to their good mechanical properties, twocomponent polyurethane materials can be used for grouting to treat the fouling problems caused by ballastless track mud pumping
Summary
By the end of 2020, the total operating mileage of highspeed railways in China reached 39,000 km, with ballastless tracks being the main track structure type due to their excellent integrity, superior durability, and good strength properties. Existing studies have mainly focused on the engineering backgrounds of water conservation, structure lifting, and foundation treatment and reinforcement These applications are considerably different from the treatment of ballastless track mud pumping. We conducted laboratory tests to study the evolution of compressive, tensile, and bonding strengths of polyurethane elastomers under the effects of different material components On this basis, the optimal ratio of a polyurethane elastomer suitable for the treatment of mud pumping in subgrade beds under ballastless tracks was put forward. By using chain-extending cross-linking agent and solvent content as variables, the determined design ratio was tested, and an optimal ratio of polyurethane grouting material suitable for ballastless track mud pumping treatment was proposed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
