Sealing means

In a tunnelling machine of the type in which a pressurized liquid is used in front of a bulkhead on a shield and in which the tail-piece of the shield overhangs an installed tunnel lining, the improvement comprising the provision of a seal against leakage of said liquid into the tunnel workings through the space between the tail-piece and the lining, said space being non-uniform about said tail-piece and said lining, said seal comprising flexible elongated fibres, a mount for said fibres from which the fibres project in brush-like form, each fibre following substantially the same direction, said mount being fixed to the tail-piece in a substantially fluid-tight manner and arranged to permit said fibres to extend generally at an angle substantially less than 90.degree. to the surface of the tail-piece, with a portion of the fibres lying substantially parallel to the outer wall of the tunnel lining and in close contact with each other, portions of the fibres contacting said tunnel lining, the seal bridging the gap between said tail-piece and said tunnel lining.

In a tunnelling machine of the type in which a pressurized thixotropic fluid is used in front of a bulkhead on a shield in which the tail-piece of the shield overhangs an installed tunnel lining, the improvement comprising the provision of a seal against leakage of said liquid into the tunnel workings through the space between the tail-piece and the lining, said space being non-uniform about said tail-piece and said lining, said seal comprising flexible fibers, a mount for said fibers from which the fibers project in a brush-like form, said mount being fixed to the tail-piece in a substantially fluid-tight manner and arranged to permit said fibers to extend generally at an angle substantially less than 90.degree. to at least the surface of the tail-piece, with a portion of the fibers lying substantially parallel to the outer wall of the tunnel lining and in contact with each other, a portion thereof contacting said tunnel lining wherein said fibers trap the thixotropic fluid to thereby increase the effectiveness of said seal.

In a tunnelling machine of the type in which a pressurized liquid is used in front of a bulkhead on a shield and in which the tail-piece of the shield overhangs an installed tunnel lining, the improvement comprising the provision of a seal against leakage of said liquid into the tunnel workings through the space between the tail-piece and the lining, said space being non-uniform about said tail-piece and said lining, said seal comprising flexible fibers, a mount for said fibers from which the fibers project in a brush-like form, said mount being fixed to the tail-piece in a substantially fluid-tight manner and arranged to permit said fibers to extend generally at an angle substantially less than 90.degree. to at least the surface of the tail-piece with a portion of the fibers lying substantially parallel to the outer wall of the lining and in contact with each other, a portion thereof contacting said tunnel lining.