Soil Pressure Drops of Various Screw Conveyor Structures for Shield Machines.

Pressure drop of the screw conveyors filled with plasticized soil for earth pressure shield machines can be calculated by the method described in the previous paper. In this paper, equations of the pressure drop for the shaftless coil screw called the ribbon screw and various conveyor structures have been formulated. On comparison of the calculated pressure drop, the screw with rotary casing showed the larger pressure drop, which is about twice that of a conventional type of conveyor.