Mobile train for backfilling tunnel liners with cement grout

DETAILED DESCRIPTION The present invention comprises generally a machine for grouting an annular cavity formed intermediate an elongate external bore and a tubular internal member disposed in the bore.
The machine comprises a vehicle configured for longitudinal movement in the tubular internal member, means for supplying cement slurry to the vehicle from a remote site, foam generating means mounted on the vehicle for forming finished foam, mixing means mounted on the vehicle for mixing the finished foam with the cement slurry to form foamed cement grout, and means for injecting the foamed cement grout from the vehicle into the cavity intermediate the tubular internal member and the external bore.
In a preferred embodiment, the elongate external bore is a tunnel bore and the tubular internal member is a tunnel liner, and the remote site from which the cement slurry is supplied to the vehicle is located at a position outside of the tunnel bore.
The means for supplying the cement slurry to the vehicle may comprise a cement mixing plant located on the surface of the ground outside of the tunnel bore for mixing the cement slurry, a conduit connecting the cement mixing plant to the vehicle, and a pump for pumping the cement slurry from the mixing plant to the vehicle through the conduit.
The vehicle of the grouting machine may comprise a train of wheeled cars which extend longitudinally within the tunnel liner.
These wheeled cars are preferably attached to at least one tractor for moving the train longitudinally through the tunnel.
The means for injecting the foamed cement grout into the cavity between the inner and outer members may comprise a primary conduit having a first end connected to the train for receiving the grout pumped from the train, a manifold connected to the second end of the primary conduit, and a plurality of flexible hoses mounted to the manifold so that the foamed cement grout is distributed to the hoses from the manifold.
An injection fitting is mounted to the second end of each of the hoses for injecting the grout into the cavity between the liner and bore