Microtunnel Grouting

Microtunnels and Shore Crossings pose unique grouting challenges, including deep horizontal pours against inflatable packers over long distances.

We provide solutions to numerous clients and are the world-leaders in the grouting of large-diameter tunnels at shallow angles above and below the waterline.

Using our SPM1000 Twin PAN Mixer, we can provide ultra-high-strength grouts at up to 10m3/hr.

FAQ’s

When is micro tunnel grouting required?

Microtunnels are the preferred shore crossing technique for larger diameter trunklines where Horizontal Directional Drilling does not suit.

After the trunkline is pulled in the annulus between the trunkline and microtunnel is grouted.

How is the annulus grouted?

After the pull-in has been completed, a custom designed formwork is trolleyed to the outer end of the tunnel which is then grouted to form a plug.

The tunnel can now be dewatered from the shore side and the annulus is grouted.

What are the main difficulties in grouting a microtunnel?

As with any pipe-in-pipe scenario, it is extremely difficult to deal where the trunkline comes in contact with the microtunnel.

Subcon’s fabric formworks are specifically designed to seal these tight areas to ensure the tunnel can be successfully dewatered prior to grouting.

What services does Subcon provide for micro tunnel grouting?

Subcon can provide the engineered design of the packer bags, grout mix designs, balance of plant and personnel for grout application or the complete turnkey solution.