Ground secured before, during, and after excavation.
Specialty Grouting Services provides tunnel and shaft grouting in Ontario and across Canada — pre-excavation ground treatment, TBM break-in and break-out blocks, backfill and contact grouting, and leak sealing in finished linings. Tunnelling schedules don’t forgive ground surprises; grouting is how you take the surprise out.
What is pre-excavation grouting?
Ground treatment placed before the excavation reaches it: injecting grout into water-bearing or unstable zones so the tunnel or shaft advances through improved ground instead of fighting it. It reduces inflows, stabilizes the face, and protects the surface above from settlement.
What are TBM break-in and break-out blocks?
Grouted ground zones at the launch and reception shafts, where a tunnel boring machine leaves or enters the shaft wall. These are high-risk moments — the ground is opened right at the shaft — and a properly grouted block keeps soil and groundwater under control while the machine passes through.
What happens after the liner is in?
Backfill and contact grouting fill the space between liner and excavated ground so loads transfer properly and water has no pathway. We also seal leaks in finished linings by injection — see groundwater control — and place annular fills for pipe and casing installations.
Frequently Asked Questions
Ground conditions, treatment volumes, drilling requirements, materials, and schedule constraints — night work and short possessions cost more than open access. We price from your drawings and geotechnical data.
Yes. This work is normally sequenced tightly with excavation. We plan mobilizations and crew coverage around your advance schedule and critical dates.
Cementitious grouts for consolidation, contact, and backfill work; water-activated polyurethane for active water; LDCC and sanded mixes where large volumes or annular fills are involved.
Yes. Injection pressures, volumes, and locations are recorded and reported, so the ground treatment can be verified against the specification before excavation reaches it.
Highways & TunnelsSEM Tunnel Injectable Tubing Injections — Highway 407 & Jane StreetCold joints in a sequential excavation method tunnel sealed through pre-installed injectable tubing, with every joint documented port by port.Read the case study
Rail & TransitTransit Tunnel Joint Sealing & Backwall Grouting — CalgaryLeaking joints in a light rail tunnel sealed and voids behind the liner filled at track level during overnight possessions, without disrupting service.Read the case study
Rail & TransitRail Crossing Casing Annular Grouting — Douro Street, TorontoA 50 m, 1,200 mm casing carrying thirty FRE ducts under the rail corridor filled with 46 m³ of lightweight grout at 20 psi — every duct proven clear on completion.Read the case studyTake the Surprise Out of the Ground
Send the alignment, geotechnical data, or the leak location — we’ll propose the grouting approach.