FBG應用於潛盾隧道環片變形監測之可行性研究

Abstract

潛盾隧道環片受力分析大多以經驗法則考慮現場環境下之土壓力行為。潛盾隧道環片從鑄造、搬運、安裝乃至於施工完成受周圍環境影響，環片受力的情況可能比設計所考慮之條件更複雜。過去曾嘗試使用應變片與光纖感測系統來監測潛盾隧道環片之受力情形，但大多受到監測技術限制，而導致所獲結果有限。本研究於隧道環片中安裝光纖光柵鋼筋感測器，從鋼筋籠之組立、混凝土澆置、各階段養護至環片抗彎試驗，進行完整記錄。對於日後隧道開挖、完工以及營運通車之環片受力狀況，提供一完整可靠的安全監測數據。藉由FLAC模擬單一環片抗彎試驗，與現場所量測之數據比較，相互確認量測與分析結果之可靠性。本論文敘述光纖光柵黏著技術之研發、現場監測與數值分析之結果。

The empirical procedures typically used in shield tunnel lining design consider the earth pressure distributions expected in the field. Due to drastic variations in the environment, the loading conditions experienced by the tunnel lining segments during fabrication, transportation and installation can be rather much more complicated than those considered in the design. Attempts have been made to measure the loading conditions within the tunnel lining segments using either strain gages or fiber optic sensors. Hampered by drawbacks in their monitoring techniques, these attempts had limited success. The technique of monitoring strain from within a reinforcement steel using fiber Bragg grating (FBG) has been developed in this research. With the FBG installed in the reinforcement, a complete record of strains experienced by the tunnel lining segment from fabrication, concrete pouring, curing through the loading tests was obtained. This technique enables the strains experienced by the shield tunnel lining system be monitored on a long term basis throughout the periods of tunneling drilling, lining installation as well as subway operation. The lining segment loading test was numerically simulated using FLAC. A comparison between the FLAC computations and FBG measurements was made to evaluate the reliability of the FBG readings. The thesis narrates the development of the FBG adhesion and monitoring techniques, as well as the results from numerical analysis.