Common Leak Problems in Utility Tunnels
- Leakage at deformation joints, settlement joints and construction joints, often through failed buried waterstops;
- Cracks in floor slabs, walls and roof slabs caused by structural settlement or thermal movement;
- Seepage at cable and pipe penetrations, lifting-eye holes and precast component connections;
- Damp areas and efflorescence where the original waterproofing membrane was damaged during backfilling;
- Flowing water at expansion joints in galleries built in high-water-table ground.
Our Solution System
We begin with an on-site diagnosis: the crew traces the real water path, marks active leaks and distinguishes static cracks from moving cracks. Based on the findings, we select the appropriate combination of materials and methods.
- Deformation and settlement joints: routed out, fitted with injection ports and sealed with rapid-setting plugging compound, then injected with flexible grout or polyurethane/epoxy systems that tolerate joint movement;
- Static structural cracks: pressure-injected with AS grout or high-strength specialty grout, which bond the crack faces together and restore structural integrity;
- Active flowing water: stopped first with quick-setting inorganic plugging material, then strengthened by epoxy or cementitious grout injection;
- Large damp areas: treated with cementitious capillary crystalline coating that grows insoluble crystals inside the concrete pores;
- Penetrations and openings: sealed with Waterproof Master or Keqiangshen materials and restored to a smooth, durable finish.
Why It Works
The key to lasting utility-tunnel waterproofing is treating the water channel inside the concrete, not just painting over the surface. Our injection grouts travel along the crack and joint network, fill voids and honeycombed concrete, and react to form permanent, insoluble seals. The AS grout additionally retains residual active material: if a new fracture opens nearby, migrating water carries the active ingredients to the new face, where they react again and self-heal the defect.
All work can be scheduled around utility access windows and carried out from the inside (negative side), so excavation and removal of the external membrane are usually unnecessary.
Materials Used
Typical materials for utility-tunnel projects include AS grout, high-strength specialty grout, specialty epoxy resin, Waterproof Master, DPS penetrative crystalline agent, cementitious capillary crystalline coating, Keqiangshen anti-seepage agent and the 703 waterproofing agent. Each is manufactured in-house and matched to the leak type, water pressure and structural condition.