AN EXPERIMENTAL STUDY OF MULTI-CIRCULAR FACE SHIELD TUNNELLING

Using an ordinary circular shield for construction of double track railway tunnel, the cross section becomes larger than the net required section. As a result, the construction work takes not only more cost but also longer time. The multi-circular face (MF) shield tunnelling has been developed to mitigate these problems, and can build a tunnel with a special cross section comprising multi-circles partially overlapped.In this study, the experiment is executed to make clear the basic behaviors of double-circular face shields (one with two faces aligned horizontally and the other with faces aligned vertically). The results show that the cutter torque and total thrust force of the MF shield are smaller than those of a circular face shield to construct the same double track railway, and that the MF shield has good characteristics in the stability of a cutting face and in its maneuverability.