Mud Pumping in Ballastless Slab Track of High-Speed Railway and Its Remediation

Abstract

Mud pumping is an increasing subgrade distress in ballastless slab track of high-speed railway, which heavily affects the driving comfort and even threatens the driving safety. However, the existing researches mostly focused on the water-induced distress in ballasted railway, and little attention was paid on the mud pumping in ballastless slab track. In this paper, both in-situ investigation and discussion of the conventional grouting remediation method were carried out. It can be observed that mud pumping mainly occurred at the expansion joint located at the ends of concrete base and then expanded to both sides of the expansion joint from 1–2 m. The defects in railway structure and the standing water stored in the roadbed layer were the two main factors contributing to mud pumping. In addition, based on the traditional chemical glue injection (CGI) remediation method (the shallow grouting repair method), a modified polyurethane grouting remediation method (the deep grouting repair method) was put forward to treat mud pumping in ballastless slab track.