Ground
Track and slab re-levelling
When the ground under slab track softens, the track settles and the speed restrictions follow. We lift the slabs back to level with polyurethane injected beneath them, in small steps inside the traffic block, and treat the formation so the next monsoon does not undo the work.
When to call us
The signs
- Ballastless track that has settled, with twist, cant or profile out of tolerance.
- Settlement at transition zones: tunnel to embankment, embankment to bridge.
- Floor slabs, yards and pavements that have settled or rock under load.
- Repeated corrections that last only until the next monsoon.
- 1Note 1: Design level of the track (green dashes).
- 2Note 2: Slab settled below level, with the formation under it softened by water.
- 3Note 3: PU injected through holes in the slab, lifting it in small, controlled steps.
- 4Note 4: Levels read on each rail after every cycle, so cant and alignment are held.
- 5Note 5: The gap under the lifted slab filled with non-shrink cementitious grout.
- 6Note 6: Weak formation grouted, so the slab does not settle again.
- 7Note 7: Slab back on the design level.
How we do it
Method, step by step
Survey
A level survey of each rail and an MASW, ERT or GPR survey of the ground beneath.
Design
Lift per point, injection points, quantities and sequence, in a method statement for the owner’s approval.
Lift
PU injected through holes in the slab in small, controlled steps, with levels read on each rail after every cycle.
Fill the gap
The space under the lifted slab filled with non-shrink cementitious grout.
Treat the cause
Formation permeation grouting and, where water is the cause, a cut-off on the side it comes from.
Prove
Levels measured under traffic, and the ground surveyed again after treatment.
What we use
Made at our plant in Alwar
Quality
Checks and proof
- Levels on each rail after every lift cycle; cant held by lifting each rail separately.
- Slabs watched for cracking at the joints while lifting.
- MASW or other survey before and after, and levels under traffic after the work.
On record
Where we have done it
- Sumber Yard, USBRLGrouting to re-level settled ballastless track slabWork completion certificate, June 2025. Performance: Satisfactory. Certified
Questions
What clients ask
Does the line have to close?
No. On T-46 P2 at Sangaldan the work was done in night blocks with about five to six effective hours, and the track was cleared before the first train. No traffic block was needed beyond the planned night blocks.
How much can a slab be lifted?
On T-46 P2 the largest lift was 136 mm, in steps of 15 to 20 mm per cycle so the concrete could reseat without cracking. Each job is designed on its own survey.
Will the track settle again?
Only if the cause is left in the ground. That is why we survey the ground first and treat the formation and the water, not just the slab. On T-46 P2 the residual settlement measured after traffic resumed was 0 mm.
Related services
Often used together
Ground investigation and monitoring
ERT, GPR and MASW surveys, boreholes, lab tests and instruments, before and after treatment.
Permeation and chemical grouting
Weak, loose or wet ground strengthened and sealed by resins and gels that fill it without moving it.
Curtain and consolidation grouting
Seepage cut-offs and foundation consolidation for dams, barrages, shafts and structures.
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