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年度	99	專案性質	實驗性質
專案類別	模場試驗	研究主題	調查
申請機構	國立中央大學	申請系所	應用地質研究所
專案主持人	陳家洵	職等/職稱	教授
專案中文名稱	多深度微水試驗測試段長度對水利傳導係數推估之影響
中文關鍵字	多深度微水試驗；水力傳導係數；測試段長度
專案英文名稱	Influence of the Test Length of a Multilevel Slug Test on the Estimation of Hydraulic Conductivity
英文關鍵字	Multilevel Slug Test；Hydraulic Conductivity；Test Section
執行金額
執行期間	2010/12/29 至 2011/12/28
計畫中文摘要	含水層的異質性影響地下水流場、污染物溶解相流布、及非水相液體遷移，是設計污染整治和選用整治技術上的重要考量因素。多深度微水試驗(multilevel slug test, MLST) 是一種單井雙封塞技術，可有效決定測試井周圍含水層水力傳導係數的垂直異質性，K(z)。在場址中不同位置的監測井執行 MLST 則可獲得場址的三維異質性 K(x,y,z)。受限於雙封塞系統的結構和 MLST 實際施作因素，測試段長度 ls 以 0.25m 至 1m 為宜。K(z)的解析度及 MLST 工作量均和 ls 呈反比。本計畫的目的是評估測試段長度對 K(z)的影響，並決定兼顧 K(z)解析度和 MLST 工作量平衡的測試段長度。在三口井使用四個不同測試段長度(ls=0.25m、0.5m、0.75m、及 1.0m)進行 158 次 MLSTs，和三口井的全篩段微水試驗(full screen slug test，FST)。結果顯示在垂直異質性相當弱的局部深度範圍內，四個測試段長度所得的 K(z)分布情況和解析度相當一致，可選用最長的測試段長度(ls=1m)以減少 MLST 工作量。在不同程度的垂直異質情況下，ls=1m 所得 K(z)的解析度最差，ls=0.25m 和 0.5m所得 K(z)的解析度大約相同，所以使用 ls=0.5m 足以反映垂直異質性變化。由於場址異質性屬事先未知，因此建議測試段長為 0.5m(左右)，以減少 MLST 工作量及調查成本並且兼顧水文地質的變異性。FST 所得的K值為全篩段的垂直平均水力傳導係數，無法有效反應垂直異質性；K水文地質代表性並不明確。對場址調查或污染整治設計而言， K較缺乏實用性，故不建議使用全篩段微水試驗進行場址調查。
計畫英文摘要	As an important factor in remediation design , aquifer heterogeneity significantly influences groundwater flow field, the distribution of dissolved solutes, and migration of nonaqueous ph ase liquids. The multilevel slug test (MLST) is a single-well technology that employs the double-packer system for the determination of the vertical heterogeneity of hydraulic conductivity, K(z). A three -dimensional K(x,y,z) can be obtained by conducting the MLST in different wells at a site. Limited by the structure of the double -packer system and by the MLST operation, the test section length l s is normally between 0.25 to 1.0 m. The test section is a perforated pipe that connects the two packers. Both the resolution associated with the K(z) obtained and the work load of the MLST are inversely proportional to l s. The purposes of this project are to evaluate the influence of ls on K(z) obtained and to determine the test section length appropriate for a balanced weight on a sufficient resolution of K(z) and the work load of the MLST. In three wells, a total of 158 MLSTs using different l s (0.25, 0.5, 0.75, and 1.0m) were conducted. In addition, three full screen slug tests (FSTs) were performed in the three wells, respectively . The results show that in some small areas of little vertical heterogeneity, the resolutions and profiles of K(z) from the four different l s are about the same, so one can choose the longest possible test section length (l s= 1.0m) for the MLST. Under different vertically heterogeneous conditions, however, l s=1.0m yields the worst resolution for K(z), and the profiles and the resolutions of K(z) from l s =0.25 and 0.5m are about the same, indicating l s=0.5 m is sufficient to reflect the vertical heterogeneity. Since aquifer heterogeneity is unknown a priori, it is suggested that ls=0.5 m be used in the MLST in order to reduce the work load as well as to obtain sufficient resolution for K(z). As far as the FST is concerned, the K value obtained represents the vertically averaged hydraulic conductivity over the full well screen, which fails to reflect the vertical heterogeneity and has an unclear hydrogeologic al meaning. Because of lacking practical usefulness of K in the remediation design, it is suggested that the FST not be u sed for site investigation.