https://scholars.lib.ntu.edu.tw/handle/123456789/86185
標題: | 行政院國家科學委員會專題研究計畫期中進度報告:濁水溪沖積扇三維水文地質特性受集集地震影響之研究(1/3) | 作者: | 劉振宇 | 關鍵字: | 同震地下水位;水文地質;地下水流模式;參數優選;Coseismic water-level change;hydrogeology;groundwater model;parameter identification | 公開日期: | 2004 | 出版社: | 臺北市:國立臺灣大學生物環境系統工程學系暨研究所 | 摘要: | 自然狀態中,大部分含水層參數性質均呈現異質及異向性,例如水力傳導係數(K) 以少數觀測資料推估其空間分佈時,結果相當不確定性,水力傳導係數是分析水文地質、 地下水流及污染傳輸極為重要之參數,集集地震引致地下水位異常變化,亦可能造成土壤 結構及水力傳導係數之改變。 本研究是將集集地震引致同震地下水位變化視為大自然本身執行微量試水試驗之水 位變化,首先分析非侷限含水層、侷限含水層與山區之同震水位離震央距離與流通係數之 關係,接著探討個別觀測井同震水位變化,但均未獲得具體之相關性,目前則進行 MODFLOW 模式模擬地震後地下水位回復之過程,並使用UCODE 模式進行參數優選,推 估震後水力傳導係數之空間分布及受地震可能造成之改變。 The spatial distribution of natural aquifer properties, such as hydraulic conductivity (K), often exhibits extreme heterogeneity and anisotropy. However, a field investigation can only survey and analyze a small fraction of in-situ data, due to limitations of time and cost. Therefore, the sparsely measured data contain considerable levels of uncertainty. Hydraulic conductivity is an important parameter for the investigations of the hydrogeology, groundwater flow and contaminant transport. Soil structures and hydraulic conductivities maybe vary due to the 1999 Chi-Chi earthquake in the Choushui River alluvial fan. In this study, the changes of groundwater level induced by the Chi-Chi earthquake are regarded as the water-level fluctuations of a slug test made by nature. At first we analyze the relationship of coseismic water-level change versus the distance from epicenter and transmisivity of wells in unconfined, confined aquifer and mountain region. We also analyze the recovery of water level in selected observation wells. The results indicate that there is no definite relationship can be drawn among the water-level change versus distance from epicenter and transmisivity. The groundwater model MODFLOW, coupled with the automatical calibration model, UCODE are thus adopted to simulate the recovery of coseismic water-level changes to determine the changes of K caused by the Chi-Chi earthquake. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/10772 | 其他識別: | 922313B002104 | Rights: | 國立臺灣大學生物環境系統工程學系暨研究所 |
顯示於: | 生物環境系統工程學系 |
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922313B002104.pdf | 67.74 kB | Adobe PDF | 檢視/開啟 |
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