分布式應變感測光纖技術於大型山崩物理模型試驗之應用初探

Due to Taiwan’s unique and young geological conditions, as well as recentextreme weather changes and concentrated rainfall (in time domain and regionalarea), slopes collapse frequently raise the reservoir sedimentation, leading thereservoir capacity and siltation problems. Meanwhile, mountain road orcommunity disasters will also be affected due to landslide. Most landslides canbe distinguished into deep-seated and shallow slope sliding. Among them,shallow slope sliding generally occurs when the slope is steep and the geologicalmaterials are poorly cemented, whilw slope sliding in the deep layer is anotherimportant consideration, and the causes of collapse can be basically divided intoearthquakes and rainfall. The collapse caused by heavy rain has the samephysical mechanism as the above-mentioned shallow collapse. The main reasonis that the rainwater seeps into the underground, and the pore water pressure inthe rock rises, reduceing the effective strength between the surface soil layer andthe intact rock pan.In view of the importance of early warning, the applicants of this project arecurrently actively promoting the integration of satellites images, in addition toTime Domain Reflectometry (TDR) in landslide monitoring applications. InSARmonitoring via long-term LOS (Line of Sight) displacement analysis is currentlyunder standardization, combined with the development of regional dual-frequencyGNSS displacement monitoring components. These methods try to merged indifferent temporal and spactail scales observations for better early warning ofcomposite shallow/deep-seated landslide. One of the features is that thisresearch attend to incorporate the application of optical fiber sensor fordistributed strain measurement, in which the Brillouin Optical Time DomainReflectometry (BOTDR) is the main technology. Therefore, the objective of theproject is to develop the BOTDR monitoring technology for shallow/deep-seatedlandslide through the establishment of BOTDR operation by indoor calibrationmethods, including self-embedded and fixed methods and co-construction withinclinometer, and coordinated with preliminary large-scale model test controlledby rainfall. By comparing BOTDR with TDR, inclinometer and SAA measurementresults, as well as with numerical simulation, this sudy persues confirming theaccuracy and stability of the BOTDR measurement, so as to makerecommendations for the measurement with standard procedures.