Optimal Location of Receiving Transducers and Optimal Observation Policy for Detecting Anomalous Plane Object in Shield Construction Method

Abstract

In excavating tunnels for subways and power cables, shield tunneling machines, which have many cutters, are used. We previously proposed an effective detection system, for the machines, which detected anomalous objects ahead, to prevent the cutters from getting damages and also to prevent the construction delay caused by the accident. The system had one sonic transmitting transducer and several sonic receiving transducers to get information on the anomalous objects. Not so many observations being available in the detection, optimal observation policy is of a practical importance. From this viewpoint, we next considered the optimal location of the receiving transducers on the cutter plane of the shield tunneling machine and also the optimal observation policy, which took into account the rectlinear and revolving motions of the cutter plane caused by the movement of the tunneling machine, for the case where the anomalous objects were lumped ones. This paper proposes the optimal location of the receiving transdusers and optimal observation policy for detecting anomalous plane object and shows that the same result as before is obtained even for the anomalous plane object.