METHOD AND DEVICE FOR DETECTING GROUND SINK IN ELEMENT TOWING AND PROPELLING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method and a device for detecting a ground sink beforehand in an element towing and propelling method such as a pipe roofing method. SOLUTION: Flexible tubes are installed under the ground in a direction crossing the center axies of the tubes inserted into the ground. Optical fiber strain sensors are fitted to the flexible tubes integrally with each other so that the ground sink can be detected by signals from the optical fiber strain sensors obtained through the strain of the flexible tubes. COPYRIGHT: (C)2004,JPO