APPARATUS FOR MAKING UNDERGROUND PASSAGES

摘要

An apparatus for forcing tubular elements through soil so as to make underground passages. Hydraulic jacks are mounted in a cylindrical casing having open ends, for reciprocation axially of the casing. At least one elongated tubular element is provided which is to be axially forced into the soil by the jacks and which has a circumferentially complete annular cross section. A plurality of pressure-transmitting members are provided which are to be interposed between a trailing end of the tubular element and the hydraulic jacks. These pressure-transmitting members each have a circumferentially complete annular cross section corresponding to that of the tubular element and are composed essentially of high-strength reinforced centrifugal concrete provided with annular metallic reinforcing rings embedded at opposite axial ends of the respective pressure-transmitting member.