光纤岩层滑动传感监测原理及试验研究

EXPERIMENTAL RESEARCH AND ROCK SLIDING MONITORING OF OPTICAL FIBER SENSING

将光纤传感技术用于岩层界面滑动损伤监测,是常规的滑坡监测手段无法相比的技术手段。基于光纤微弯损耗机制及光时域反射技术,构建光纤滑动传感监测系统及数据采集,首次提出利用土工大三轴剪切试验手段完成模拟,同时也解决了固体材料滑动瞬间断裂以及光学–力学数据转换极难采集的难题,测得滑距–光损耗对应关系数据及关系曲线。提出将光纤滑动传感监测应用于高边坡滑动监测的典型布置方式。结果表明,光纤传感监测十分敏感,损耗值达30～50 dB,滑动监测光纤的动态范围达3.0～3.5 mm。

Optical fiber sensing can be applied to monitoring sliding damage of terrain interface, for which the general monitoring means can＇t do. Based on microbending loss mechanism of optical fiber and optical timedomain reflectormetry （OTDR） technique, the monitoring system of optical fiber sliding sensing and data collection system are constructed. Triaxial shear test of soil is firstly used to construct monitoring system and data collection. The difficulty of optical-mechanical data collection for instantaneous brittle fracture of the solid material is solved. The relation data and curve of sliding distance versus loss are obtained. The embedding mode of optical fiber applied to high rock slope for sliding monitoring is presented. It shows that the optical fiber sensing system is high sensitive, light loss is 30 to 50 dB and the dynamic range of optical fiber sliding monitoring reaches 3.0 to 3.5 mm.