抄録
In excavating tunnels for subways and power cables, shield tunneling machines are used. The authors previously developed, for the machines, an automatic detection system which detected anomalous objects to prevent the cutters of the machines from being damaged and also to avoid the construction delay caused by the accident. The detection system used one transmitting and several receiving transducers (both sonic) located on the cutter plane of the machine to gather information on the anomalous objects and made use of the modeling of the transducers in order to realize a high-accurate detection of the reflected waves from the anomalouss objects even when they were superimposed to each other.
The paper proposes, based on the modeling and also the Snell's law on sonic wave reflection, a much more improved detection system which enables not only an accurate location of the objects, but also the measurement of the patterns of the objects. The validity of the proposed system is finally demonstrated with experiments in anechoic water tanks.
