Tunnel Grouting
Tunnel grouting systems are utilised to fill voids between two materials such as a host pipe and a liner or between the pipe and the surrounding geological structures at a junction.
To help the tunnelling industries, a range of soil and rock grouting techniques have been deployed. The goals are typically related to enhancing stability and groundwater control, either at the tunnel face or at the connections. This system is primarily intended to support the back grouting of the tunnel’s ring segments. The main grout pump can be regulated to maintain pressure or flow, and the additive pump will maintain the correct proportionate flow automatically.
The grouting procedure is used to improve the permeability of the rock mass, which is otherwise fragmented due to poor rock quality. Grouting is also utilized to achieve as close to a fully bonded contact as feasible between any concrete structure and adjacent rock by filling gaps between the underlying surface and the surrounding rock body caused by the sheer presence of shrinkage or other construction flaws. It also increases rock strength by consolidating degraded rocks using the consolidation grouting method and limiting leakage by creating an impermeable stratum and an appropriate drainage system or curtain grouting.
In the case of power tunnels, grouting is required in multiple sections to reap the benefits in the following ways:
Contact grouting – Filling huge gaps behind steel and concrete liners caused by inadequate concreting or air trapped during concreting operations.
Embedment grouting – To seal the gap between the steel liner and the concrete that arises as a result of concrete shrinkage, plastic set in the rock during loading/unloading, and thermal differential between the liner and the mass rock.
Consolidation grouting -Used to consolidate blast-damaged or relaxed rock while reducing leakage.
Tunnel grouting is done for a variety of reasons, some of which are listed below:
- To fill the spaces between the concrete lining and the rock surface.
- To reduce drainage issues during tunnel driving and concrete liner installation.
- To ensure the rock mass in the power tunnel's surroundings is strengthened and permeable.
- To minimize water intrusion from the tunnel lining.
