Hokkaido Toyohama tunnel rock mass collapse accident which was generated on the dynamic phase observation of the rock slope on February 10th, 1996 is made to be an opportunity, and the establishment of measurement monitoring technique of the rock slope becomes large problem. Then, it is necessary that in the especially steep rock slope, it is wide, and that it measures many observation point throughout the long term. On the assumption of applying to actual field measurement as dynamic phase observation mechanism of rock slope by optical fiber sensor, this study examined method of fixation for catching tension and compressive strain. Then, various conflI111ation tests in the method of fixation were carried out. On the basis of the result, actual fracture rock slope optical fiber sensor V-shaped and injecting static crush agent in the rock slope, the rock mass was artificially displaced, and output characteristics of that time optical fiber sensor were examined. In addition, on artificial1y displaced position by parallely installing the displacement gage with optical fiber sensor, measurement.
Though the optical fiber has made the main part of present optical communication technique, it is noticed as sensor line which applied characteristics of the optical fiber recently. After that the optical fiber has the function of strain sensor is confirmed, and after the strain measurement technology is established, applied technology is examined. It is necessary to measure many observation point in rock slope which is especially steep from present state in which the establishment of measurement monitoring technique of rock slope becomes large problem throughout long term in the rock slope. It has been confirmed here that the light strain sensor can be detected for the displacement of the minuteness high-precise. And, the power supply is unnecessary for the field, and it is little-loss, and it is possible to carry out remote monitoring over several km. Therefore, it seems to be able to sufficiently utilize it as dynamic phase observation technique of the rock slope. However, in the application of the rock slope that the unresolved part has mainly been left on relevance between behavior of rock mass and measured data, installation method, protection techniques, etc. This study assumed that it was applied to actual field measurement by optical fiber sensor as nature or artificial rock slope dynamic phase observation technique. Then, method of fixation for catching tension, compressive strain was examined, and various confirmation tests in the method of fixation carry out. By on the basis of the result, it lays the optical fiber sensor in actual fracture rock slope V-shaped, and injecting static crush agent in the rock slope, the rock mass was artificially displaced, and output characteristics of that time optical fiber sensor examine. In addition, on artificially displaced position, the conventional displacement gage was parallely installed with optical fiber sensor, and simultaneously, it carried out the measurement. Then, each strain behavior was compared, and the applicability of the optical fiber sensor was examined.
