https://ir.lib.ncu.edu.tw/handle/987654321/37 Search the Channel s https://ir.lib.ncu.edu.tw/simple-search https://ir.lib.ncu.edu.tw/handle/987654321/99479 title: 臺灣地熱場址岩層裂隙流體流動特性量測 －以硫磺坪沉積岩基盤與臺東紅葉板岩為例;Measurement of Fracture Flow Characteristics in Rock Strata of Geothermal Fields in Taiwan: A Case Study of the Sedimentary Basement in Liuhuangping and the Hongye Slate in Taitung abstract: 地熱能源是臺灣近幾年積極開發的綠能之一，而要能夠有效使用地熱能源，岩體的流體儲存及移棲特性扮演重要的角色，流體儲存由岩體之孔隙率及力學內寬所決定，流體移棲特性由岩體之滲透率及水力內寬所決定。本研究利用實驗室實驗，對大屯火山地區五指山層砂岩和紅葉地區紅葉層板岩進行四項物理參數的量測，孔隙率及力學內寬透過波以耳定律來測量，對於砂岩試體來說，滲透率及水力內寬使用穩態流法；板岩試體因為屬於低滲透率岩石（k < 10⁻¹⁸ m²），超出穩態流法的測量範圍，因此使用脈衝衰減法來做測量。 砂岩完整試體孔隙率在圍壓3MPa～120MPa下，孔隙率範圍為2.7%～4.7%，滲透率範圍為 1.9 × 10⁻¹⁷ m² ～ 2.0 × 10⁻¹⁶ m²，砂岩節理在圍壓3MPa～60MPa下，力學內寬範圍為45.5μm～126.4μm，水力內寬範圍為25.9μm～8.7μm；板岩完整試體孔隙率在圍壓3MPa～20MPa下，孔隙率範圍為0.0%～5.1%，滲透率範圍為 2.3 × 10⁻²⁰ m² ～ 9.7 × 10⁻¹⁸ m²，板岩節理在圍壓3MPa～60MPa下，力學內寬範圍為72.7μm～506.5μm，水力內寬範圍為1.7μm～16.8μm。 實驗結果說明，節理對流體流動之貢獻遠大於完整岩石，本研究根據實驗室實驗的結果，估計在含節理岩體的節理間距為1公尺時，其等效滲透率與完整岩石滲透率之差異，另外板岩也進行剪應力場的不密合節理模擬，來比較密合節理與不密合節理的差異。結果顯示，在節理間距為1公尺時，節理砂岩的等效滲透率是完整砂岩的2.2～4.5倍；密合節理板岩的等效滲透率是完整平行葉理板岩的12～18倍；不密合節理板岩的等效滲透率是密合節理板岩的133～300倍。 完整砂岩和完整板岩之孔隙率與滲透率關係皆可以用指數律來描述，而節理砂岩與天然劈理密合板岩之力學內寬與水力內寬關係，其力學內寬和水力內寬之比值（E/e）有隨著水力內寬減少而增加的趨勢，天然不密合劈理板岩則呈現相反趨勢。 透過實驗結果，力學內寬要扣掉完整岩石在相同有效應力下的孔隙體積，但是水力內寬則不需考慮完整岩石滲透率之貢獻，在對於低滲透率岩石，透過脈衝衰減法（PDB）進行力學內寬量測時，是否可以忽略完整岩石孔隙率之貢獻，尚需進一步探討。 ;Geothermal energy has been actively developed as one of the major renewable energy resources in Taiwan in recent years. To effectively utilize geothermal energy, the fluid storage and migration characteristics of rock masses play a crucial role. Fluid storage is controlled by rock porosity and mechanical aperture, whereas fluid migration characteristics are governed by permeability and hydraulic aperture. In this study, laboratory experiments were conducted to measure four physical parameters—porosity, permeability, mechanical aperture, and hydraulic aperture—of sandstone from the Wuchishan Formation in the Tatun volcanic area and slate from the Hongye Formation in the Hongye area. Porosity and mechanical aperture were measured using Boyle’s law. For sandstone specimens, permeability and hydraulic aperture were determined using the Steady State method. Slate specimens, however, are classified as low-permeability rocks (k < 10⁻¹⁸ m²), which exceed the measurable range of the Steady State method; therefore, the Pulse Decay Balance (PDB) method was employed. For intact sandstone specimens under confining pressures ranging from 3 to 120 MPa, porosity varied between 2.7% and 4.7%, and permeability ranged from 1.9 × 10⁻¹⁷ m² to 2.0 × 10⁻¹⁶ m². For jointed sandstone under confining pressures of 3–60 MPa, mechanical aperture ranged from 45.5 μm to 126.4 μm, while hydraulic aperture ranged from 25.9 μm to 8.7 μm. For intact slate specimens under confining pressures of 3–20 MPa, porosity ranged from 0.0% to 5.1%, and permeability ranged from 2.3 × 10⁻²⁰ m² to 9.7 × 10⁻¹⁸ m². For jointed slate under confining pressures of 3–60 MPa, mechanical aperture ranged from 72.7 μm to 506.5 μm, whereas hydraulic aperture ranged from 1.7 μm to 16.8 μm. The experimental results indicate that joints contribute far more significantly to fluid flow than intact rock. Based on laboratory results, this study further estimated the differences in equivalent permeability between jointed rock masses with a joint spacing of 1 m and intact rocks. In addition, numerical simulations of non-mated joints under shear stress conditions were conducted for slate to compare mated and unmated joint conditions. The results show that, with a joint spacing of 1 m, the equivalent permeability of jointed sandstone is 2.2–4.5 times that of intact sandstone; the equivalent permeability of mated joint slate is 12–18 times that of intact slate with parallel cleavage; and the equivalent permeability of unmated joint slate is 133–300 times that of mated joint slate. The relationships between porosity and permeability for both intact sandstone and intact slate can be described by exponential laws. For jointed sandstone and naturally mated cleaved slate, the ratio of mechanical aperture to hydraulic aperture (E/e) increases with decreasing hydraulic aperture, whereas naturally unmated cleaved slate exhibits an opposite trend. Experimental results suggest that mechanical aperture should be corrected by subtracting the pore volume of intact rock under the same effective stress, while hydraulic aperture does not require consideration of the permeability contribution from intact rock. For low-permeability rocks, whether the pore volume contribution of intact rock can be neglected when measuring mechanical aperture using the Pulse Decay Balance method requires further investigation. <br> https://ir.lib.ncu.edu.tw/handle/987654321/99477 title: 臺北盆地工程地質分區建置 abstract: 因地質特性不同，不同區域其工程規劃、設計與施工考量即有所不同。工程地質分區旨在考慮工程地質特性均勻性，將ㄧ個大區域劃設成數個工程地質特性相似的小區域，並作為國土規劃、防災、與工程計畫推動之參考。臺北盆地歷史上經過兩次湖陸循環，地質狀況較為複雜，建立工程地質分區有助於釐清地質背景，降低工程風險。李咸亨(1996)建立第三代臺北市工程地質分區，以松山六次層的沉積物為基礎，劃分臺北市工程地質分區，以提供工程界分析和判斷地層的結構。本研究則優先考慮了基盤與安山角礫岩、礫石層等空間分布，其次考慮松山層次層的變化，並將分區範圍擴展至臺北盆地，建立新一代的地質分區，並針對各分區予以解釋。 本研究整理工程地質探勘資料庫提供之資料，建置地下地質資料庫，使用10768孔工程地質鑽井，以洪如江(1966)所提出松山層含六次層為參考，在地質剖面上以蘇品如(2018)沿基隆河、新店溪、大漢溪與淡水河繪製的沉積相地質剖面，建立本研究之分區原則，首要依序以河流主要的影響範圍劃分大分區，其次以基盤與安山角礫岩層深度、礫石層的空間分布、松四層以上次層的側向連續性劃分次分區，以松六層的厚度變化以及各主要分區中的局部地質特性劃分子分區，將臺北盆地劃分為5個大分區，包含14個次分區，其中8個次分區又可在細分為23個小分區。 研究結果考量不同分區的地層的差異，劃分不同地質條件的分區，並針對各分區的地層結構探討其可能地質背景。命名時以主要影響區域之河流、次要以行政區命名首位字母主要分區，若主分區存在子分區，則以數字編號區分。 ;Due to variations in geological characteristics, considerations in engineering planning, design, and construction differ among regions. Engineering geological zoning aims to account for the homogeneity of engineering geological conditions by subdividing a large area into several smaller zones with similar geological characteristics, thereby providing a reference framework for land-use planning, disaster mitigation, and the implementation of engineering projects. The Taipei Basin has experienced two lacustrine–terrestrial cycles in its geological history, resulting in complex subsurface conditions. Establishing engineering geological zoning in the Taipei Basin is therefore essential for clarifying the geological framework and reducing engineering risks. Lee (1996) proposed the third-generation engineering geological zoning of Taipei City based on the sediments of the sixth sub-layer of the Songshan Formation, providing a basis for engineering practice to analyze and interpret subsurface stratigraphic structures. Building upon this foundation, the present study prioritizes the spatial distribution of the basement, andesitic breccia, and gravel layers, followed by variations within the sub-layers of the Songshan Formation. The zoning extent is further expanded to cover the entire Taipei Basin, establishing a new generation of engineering geological zoning and providing geological interpretations for each zone. In this study, data from the engineering geological exploration database were compiled to construct a subsurface geological database, incorporating information from10,768 engineering boreholes. The stratigraphic framework of the Songshan Formation, including its six sub-layers as proposed by Huang (1966), was adopted as a reference. Zoning principles were established based on sedimentary facies geological cross-sections along the Keelung River, Xindian River, Dahan River, and Tamsui River constructed by Su (2018). Large-scale zones were first delineated according to the primary areas influenced by major river systems. Sub-zones were then defined based on the depth of the basement and andesitic breccia, the spatial distribution of gravel layers, and the lateral continuity of sub-layers above the fourth sub-layer of the Songshan Formation. Further subdivision into minor zones was conducted based on thickness variations of the sixth sub-layer of the Songshan Formation and localized geological characteristics within each major zone. As a result, the Taipei Basin was divided into five major zones, comprising fourteen sub-zones, eight of which were further subdivided into twenty-three minor zones. The zoning results reflect stratigraphic differences among regions and delineate zones with distinct geological conditions. The stratigraphic architecture of each zone is examined to infer its possible geological background. In terms of nomenclature, major zones are named primarily after the dominant river system influencing the area, with secondary reference to the initial letter of the administrative district. Where sub-zones exist within a major zone, numerical identifiers are used to distinguish them. <br> https://ir.lib.ncu.edu.tw/handle/987654321/99475 title: Stochastic Inversion of Hydrothermal Properties in Heterogeneous Porous Media abstract: 水熱性質是多孔介質中，控制地下水流動與熱傳遞的重要角色，對於地熱系統尤為重要。參數估計方法常被用於地熱系統的流動、傳輸行為特徵化，許多研究指出這些估算方法的有效性取決於時空數據的品質與可得性。野外量測普遍存在限制，因此對特定場址使用模型前，制定合宜之取樣策略至關重要。本研究探討隨機方法量化水熱性質不確定性之應用，並強調觀測資料在參數估計中的角色。研究初期建立二維合成含水層模型，應用於比較跨井抽水與注入情境下，不同估計方法的有效性。合成試驗顯示，相較於蒙地卡羅模擬 (MCS)，集合卡爾曼濾波 ( EnKF ) 提供更有可靠性的水熱性質參數估計結果；在熱傳導性估計，兩者方法具有高度相關係數，分別為0.913與0.926。此外，EnKF 在此研究中，於精度與計算效率間提供良好平衡，且比MCS 的計算速度快至六倍。基於這些發現，EnKF被應用於後續受控實驗室進行之沙箱試驗時，觀測數據的參數估計貢獻探討。結果指出EnKF 對估計之參數展現極高相關係數，並成功重現觀測到的熱響應。觀測網路敏感度分析指出觀測剖面達三剖面，模型表現趨於穩定。重要結果表明，於高敏感區域布設分部式觀測網路能最大化資訊可得量，而觀測初期採納高頻量測，可有效約束近場特性。此研究證實EnKF 為進行水熱特性特徵化的有效工具，並為地熱能源開發與地下特徵提供具體之資料收集策略建議。;Hydro-thermal properties play crucial roles in controlling groundwater flow and heat transfer within porous media, particularly in geothermal systems. Parameter estimation techniques are commonly employed to characterize flow and transport behaviors in geothermal systems. As recognized in many studies, the effectiveness of these estimations depends significantly on the quality and availability of spatiotemporal data. Given the typical limitations in field measurements, identifying appropriate sampling strategies is essential before applying models to site-specific conditions. This study investigates the use of stochastic approaches to quantify uncertainties in hydrothermal properties, placing particular emphasis on the role of data observation. In the beginning, a synthetic two-dimensional aquifer model was initially developed to compare the effectiveness of different estimation methods under cross-hole pumping and injection scenarios. Results from these synthetic tests highlighted that the Ensemble Kalman Filter (EnKF) model generally provides more reliable estimates of hydrothermal properties than those obtained from the Monte Carlo Simulation (MCS) method, with extremely high correlation coefficients of 0.926 and 0.913 for thermal conductivity estimation, respectively. Moreover, EnKF offers a good compromise between accuracy and computational efficiency, up to six times faster than MCS, making it the preferred approach for our studies. Building on these findings, a sandbox experiment was conducted in a controlled laboratory setting, where only the EnKF was applied to further explore the contribution of observed data to parameter estimation. The results show that EnKF achieves high correlation coefficients for estimated parameters and successfully reproduces observed thermal responses. Monitoring network sensitivity analysis reveals performance stabilization at three observation profiles. Key findings indicate that distributed observation networks with strategic placement in high-sensitivity regions maximize information gain, while high-frequency early-stage monitoring effectively constrains near-field properties. This research establishes EnKF as an effective tool for hydrothermal characterization, offering practical guidance for data collection strategies in geothermal energy development and subsurface characterization applications. Keywords: stochastic inversion, Monte Carlo Simulation, Ensemble Kalman Filter, hydro-thermal properties, geothermal system <br> https://ir.lib.ncu.edu.tw/handle/987654321/99473 title: 利用因子分析與機器學習模型探討臺灣全國尺度河川水質特性;Exploring National Scale River Water Quality Characteristics in Taiwan Using Factor Analysis and Machine Learning Models abstract: 河川為地球主要淡水來源，對生態系統與人類活動具關鍵功能。臺灣受中央山脈阻隔，短陡河川一方面承擔公共用水、農業灌溉與工業用水，另一方面維繫水生棲地與沿海生態。濁水溪、高屏溪等流域分別支撐嘉南平原及高屏地區之農業與產業發展，也是區域民生用水與環境安全的重要命脈，然而河川水質受工業、農業、畜牧與民生污水等多源污染影響，導致治理決策不確定性。本研究首先整合環境部全臺水質監測資料，結合土地利用，進行因子分析，以主成分萃取並採用Varimax轉軸，將水質與土地利用間高度相關的資訊濃縮為少數「潛在污染因子」得出因子一以亞硝酸鹽氮、硝酸鹽氮與銅、鋅、鎳及工業土地利用類呈現正向負荷，反映工業排放之氮與重金屬複合污染。因子二以氨氮，生化需氧量、總磷與大腸桿菌群和森林與溶氧量呈強負負荷。顯示森林覆蓋可提升溶氧並抑制生活與畜牧污水相關有機污染。接續以氨氮(NH₃–N)為核心，利用倒傳遞神經網路(BPNN)建立濃度迴歸模型，交叉驗證評估模型之泛化能力；結果顯示平均驗證表現為MAE=1.18、RMSE=1.98、R²=0.44，對數轉換後之觀測與預測散佈關係亦呈現一定解釋力(R²=0.519)，顯示模型可掌握主要濃度變異結構並具備實務可用性。另為治理溝通，將迴歸預測值依環境部飲用水水質標準(0.1 mg/L)門檻轉為超標風險指標，其判讀準確率85%、精確率89%、AUC=0.895，並可重現超標比例(實測59.4%、預測60.7%)。綜合結果顯示，氨氮風險西岸都市化區較高且呈熱區，森林與降雨具稀釋與淨化效益，人造建成區與特定工業用地推升負荷，可作為監測分佈點與治理優先序依據。;Rivers are a primary source of freshwater on Earth and play indispensable roles in both ecosystems and human society. In Taiwan, the Central Mountain Range forms steep and short river systems that not only supply domestic, agricultural, and industrial water demands, but also sustain aquatic habitats and coastal ecosystems. Major basins such as the Zhuoshui River and Gaoping River support agricultural and industrial development in the Chianan Plain and the Kaohsiung–Pingtung region, serving as vital lifelines for regional livelihoods and environmental security. However, river water quality is influenced by multiple pollution sources—including industrial effluents, agricultural runoff, livestock wastewater, and domestic sewage—thereby increasing uncertainty in management and decision-making. This study first integrated nationwide water quality monitoring data from the Ministry of Environment (MOENV) with land-use information and conducted factor analysis using principal component extraction with Varimax rotation. Highly correlated patterns between water quality and land use were condensed into a limited number of latent pollution factors. Factor 1 showed positive loadings for nitrite nitrogen, nitrate nitrogen, copper, zinc, and nickel, together with industrial land-use categories, indicating combined nitrogen and heavy-metal contamination associated with industrial discharges. Factor 2 exhibited strong negative loadings for ammonia nitrogen, biochemical oxygen demand, total phosphorus, and Escherichia coli, as well as forest coverage and dissolved oxygen, suggesting that forested areas enhance dissolved oxygen and suppress organic pollution linked to domestic and livestock wastewater. Subsequently, focusing on ammonia nitrogen (NH₃–N), a backpropagation neural network (BPNN) was developed to construct a concentration regression model, and cross-validation was applied to evaluate its generalization performance. The results showed an average validation performance of MAE = 1.18, RMSE = 1.98, and R² = 0.44. The scatter relationship between observed and predicted values after logarithmic transformation also demonstrated explanatory power (R² = 0.519), indicating that the model captures major concentration variability and is practically applicable. To facilitate risk communication for governance, the regression outputs were further converted into an exceedance risk indicator using the MOENV drinking-water quality threshold of 0.1 mg/L. The resulting classification achieved an accuracy of 85%, a precision of 89%, and an AUC of 0.895, while successfully reproducing the exceedance proportion (observed: 59.4%; predicted: 60.7%). Overall, the findings indicate that NH₃–N risk is higher and forms hotspot patterns in urbanized areas along Taiwan’s western corridor. Forest cover and rainfall provide dilution and purification effects, whereas built-up areas and specific industrial land-use types increase pollution loads. These results can support monitoring site allocation and help prioritize management actions. <br>