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Microtunnel Grouting

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

Subcon have provided solutions to a number of clients and are the leaders in the grouting of large diameter tunnels at shallow angles above and below the water line.

With our SPM1000 twin pan mixer we are able to provide ultra high strength grouts at up to 10m3/hr


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.

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.

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.

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.

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