RailJET®: Soft Subgrade and Embankment Stabilization, Introduction of New Hi-Rail Technology for Subgrade Maintenance

摘要

The RailJET® is a hi-rail subgrade stabilization system that installs soil cement rigid jet grouted columns below the track structure (Figure 1). These columns transfer track bed loading deeper into the subgrade strata to more stable bearing material. The application and design for these columns improve a suite of problems experienced by railroads along their track structure such as subgrade settlement, embankment instability, lateral spreading, bearing capacity failures, and saturated fouled ballast pockets. The system works on existing track under defined work windows without lasting outages or removing track structure. The RailJET® system is fully self-contained and operates under its own power without the need for a flat car or railroad provided equipment. The system can access the track from any 50-foot wide roadway or temporary crossing. No material is wasted during column installation because grout mixtures are combined at the point of injection and continuously mixed as work progresses. RailJET® columns are modeled using existing geotechnical software and methods such as elastic and/or consolidation settlement, limit equilibrium slope stability, and load/deformation based finite difference analyses. These models allow us to estimate improvements in factor of safety and expected settlement reduction after a track structure treatment with the RailJET® system. This paper will present example analyses of subgrade and embankment stability improvements after RailJET® columns are installed. Numerous RailJET® projects for heavy freight railroads have been completed to date. This paper will discuss the advantages of the RailJET® system over conventional remediation methods including, accessibility, railroad support requirements, production, performance, logistical benefits, and improvements going forward.