Railways · Tunnels
T-49B escape tunnel, Arpinchala, USBRL
In the T-49B escape tunnel at Arpinchala, on the Katra–Banihal section of the USBRL, cavities had to be treated before work could continue safely. Afcons engaged us for specialised grouting with PU-based chemicals, supply and application, to an approved method statement.
- Year
- 2022
- Location
- Arpinchala, Katra–Banihal section, USBRL
- Type
- Railway escape tunnel
- Client
- Afcons Infrastructure Limited
- Our role
- Supply and application, to an approved method statement
SubcontractSubcontract with Afcons Infrastructure, January 2022, with amendments to May 2022. Quantities paid as consumed and certified by IRCON and Afcons.
The problem
Cavities in water-bearing rock
Cavities around the escape tunnel, in fractured rock carrying water, had to be filled and the ground around them consolidated before the work could go on safely.
What we did
Two resins, matched to the void and the water
- DrucPietra, our low-foaming polyurethane silicate resin, for consolidation, and DrucHyd 2C, our water-reactive resin, where the water was flowing.
- Injected through pipes and self-drilling anchors, to the approved method statement.
- Contracted quantities of 50 t of DrucPietra and 120 t of DrucHyd 2C, paid on what was consumed and certified.
- 1Note 1: A void above the crown, left by a collapse or by overbreak.
- 2Note 2: Loose material that keeps running if it is disturbed.
- 3Note 3: Steel ribs and shotcrete holding the opening.
- 4Note 4: Pipes or self-drilling anchors drilled through the support into the void.
- 5Note 5: High-foaming PU fills the void from the bottom up and binds the loose material.
- 6Note 6: Cured foam is light, so it adds little load to the support below it.
- 7Note 7: Check holes and pressure readings confirm the void is full before the next advance.
Services on this job
Methods used
Cavity and void filling
Voids above tunnel crowns, behind linings and under slabs filled without loading the support.
Tunnel water ingress control
Leaks and inflow stopped in tunnels, shafts and underground structures.
Pre- and post-excavation grouting
Water cut off and weak ground consolidated ahead of the face; voids closed behind it.
SubcontractSubcontract with Afcons Infrastructure, January 2022, with amendments to May 2022. Quantities paid as consumed and certified by IRCON and Afcons.
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