Colliding into layers of boulder often create problems and may even result in non operation of a system. However, we have solved this problem. Unlike standard procedure where small stoned are crushed, our system, by employing super slurry, is able to remove small stones in
whole. For this reason, the hardness and ratio of small stones no longer influence performance enabling smooth driving operation irregardless of earth content.
The Vacuum Valve, which we developed, is able to remove even big boulder in succession, thereby bringing stability to the driving face.
(φ800 m/m to φ1500 m/m)
・Safely and surely reaches existing manhole and shield. Cutters and driving units are fixed by
bolts. All of them can be disassembled and recovered.
・It is very safe because no fire is required for disassembly and recovery.
・Additional injection is hardly required since the outer cylinde r is left and fixed.
・Sudden curve construction of about 20 times wider than the nomi nal diameter is possible.
・Since pushing a jacking pipe into an outer cylinder,consistent quality is gained for all spans.