Development of a dynamic field model test for pile-supported wharf in liquefied sand

[[abstract]]臺灣西岸港區大多為鬆軟之沖積地與海埔新生地屬於容?發生土壤液化之土層，因此建構於其上之港灣設施與?海建設為得到符合靜態與動態基礎承載與側向抵抗?需求，大多採用深基礎設計，其中樁基礎為最常?之選項之一。然而土壤與樁基礎結構物於液化土層之反應會受到?者互制效應影響，並?適用於一般結構物耐震設計，因此近??許多學者?用震動台等進?物?模型試驗，唯此方法仍然存在有與現地應??態情況?符之比?效應(scale effect)，因此為增進對現地土壤與樁基礎結構物互制反應之?解，進?大尺寸現地基樁動態試驗有其必要性。 本試驗於選定試驗場址開挖一長5公尺、寬2.5公尺與深2.5公尺之試坑，並且將由?根鋼管以焊接方式與頂板?接之棧橋碼頭(樁基礎結構物)安置於試坑中央，?用高速動態擷取系統以及?測元件進?大尺寸棧橋碼頭動態液化試驗。待重模試坑及各?測設備裝置完成後，於表面配置震盪震源?作為動態載重，?用地表震源以應?波形式將震波能?傳遞至重模試坑，使得水下邊坡試體產生液化或超額孔隙水壓?變化，並運用高速動態資?擷取系統即時紀?土壤、樁基礎結構物與周圍地表之反應。 試驗所得之?據包含有孔隙水壓?激發?為、土壤震動反應以及基樁動態?為，其將搭配?位?波技術、?值積分法以及p-y曲線分析方式做探討。而分析結果顯示建?之高速動態資?擷取系統、試驗程序以及資?分析方法可用以探討孔隙水壓?與樁土互制反應三者之耦合關係。並且試驗?據分析結果顯示出p-y曲線隨著震動?時?斷改變，且其與孔隙水壓?激發情況有密?關係。[[abstract]]0[[note]]碩

Sediment Environment Assessment System for the Tseng-Wen and Baihe Reservoir Watersheds in Taiwan

本研究以曾文及白河水庫集水區為例，運用易於量化、取得且能反應現況之指標，並建立指標合理變動範圍，希冀從中瞭解水庫集水區土砂環境遭遇問題及評估現況環境，供作保育治理需求參考應用。分析結果顯示，兩水庫集水區境內涉及山坡地範圍之子集水區中，有37 個子集水區屬整治需求區域，其總面積約佔整體水庫集水區之43.2%；可見莫拉克颱風後之治理工作，雖已加速水庫集水區整體土砂環境復育，但仍需嚴防道路無法抵達或採自然復育等區域，坡面上不穩定土砂造成二次災害。建議應進行集水區整體土砂災害處理策略擬訂之水土保持需求評估工作，避免後續災害的形成與擴大。This study completed the assessment of the sediment environment of the Tseng-Wen and Baihe Reservoirs, considering the factors of sediment-related disasters to evaluate the threat of sediment production and plan the requirements of soil and water conservation works for the reservoir watersheds. Case studies suggest the post-typhoon Morakot sediment environment of the Tseng-Wen and Baihe reservoir watersheds in 2014 has recovered well after remediation, but is still in a relatively poorer condition than pre-typhoon Morakot. Further, to limit the occurrence of secondary disasters in disaster-prone creek watersheds, this study suggests a list of watersheds requiring improvement to their sediment environments under the suggested potential sediment production classification. Consequently, there are 37 areas located in the Tseng-Wen and Baihe reservoir watersheds still requiring soil and water conservation works. These observations can serve as the basis for effectively managing reservoir watersheds, planning of disaster prevention work and reducing the risk of rapid sedimentation in reservoirs during the flood season