Pipe placement with pit forwarding in water-laden ground - involves pressing cutter shoe through cleared opening in pit end concrete walling

摘要

Excavation of the pit is effected on attaining groundwater level (6), with water supplied to maintain this in the pit (1), in a process for making ducts with work shafts or pits by pressing forward in ground carrying water. A watertight concrete bottom (4) is made, using cement which sets under water. Water in the pit is pumped out, when this has set. The bottom is filled with concrete between pile walls (2), to form the pressing vat (8). An end wall of concrete (10) is constructed at the end of the pit in the direction (9) of forwarding duct pipes. This has an approach opening (11), and an annular peripheral seal (12) of elastic material. Pile wall boards (3) are raised above the approach opening, far enough for a sealed cutting shoe (13) to be pressed through it in front of the length of pipe.