地層下陷分佈式水壓與沉陷監測系統之研發

Abstract

光纖感測技術具有體積小、重量輕、不會受潮短路或電磁波干擾、耐久性高、訊號可長距離傳輸(10公里以上)與可在單一線上同時串連多組感測器等優點。本研究主要目的在於充分利用上述光纖感測之優勢，研發適用於地層下陷量測之光纖光柵（FBG）沉陷計並與FBG水壓計整合，建立可在單一鑽孔內同時量測地層下陷與水壓分佈變化之感測技術。為驗證其現地實用性，於雲林縣虎尾鎮光復國小建置一監測井，將研發完成之FBG水壓與地層下陷監測系統安置於內，同時進行土壤採樣及物理性質試驗。2012年4月底，系統安裝完成後以每月乙次之頻率進行量測，亦嘗試進行一次24小時及72小時連續讀數紀錄。本論文敘述相關光纖光柵感測系統之研發與改良，並根據現地經驗建立安裝方法之標準流程，以及討論本FBG整合式感測系統使用之成效。

Optical fiber sensors have the advantages of being small, light-weight, immune to short circuit or electromagnetic interference, durable, good for long distance data transmission (over 10km) and multiple sensors can be connected to a single optical fiber. This research intends to make use of these advantages, develop an optical fiber Bragg grating (FBG) extensometer that is capable of monitoring ground subsidence. When coupled with FBG piezometers, the integrated sensor system can be deployed to monitor pore-water and ground subsidence profile simultaneously, in a single borehole. An observation well was established at Guon-Fu elementary school, in Hu-Wei Township of Yun-Lin County, where the developed sensor system was installed and soil samples taken for physical property tests. The field installation was completed in the end of April, 2012. The FBG sensor readings were taken on a monthly basis. A continuous 24 hour and 72hour reading were also taken for the analysis of daily variations of pore-water pressure and ground subsidence profiles. This thesis describes the development and improvement of the FBG sensor system, and the standard procedure for sensor system installation according to experiences gained in this research. The effectiveness of the integrated FBG sensor system is discussed.