地下水位歷線與沉陷檢測資料之應用

Application of Groundwater Hydrographs and Detected Data of Land Subsidence

施清吉(Ching-Chi Shih) ； 陳致宏(Chih-Hung Chen)

《農業工程學報》 52卷1期 (2006/03) Pp. 75-89

https://doi.org/10.29974/JTAE.200603.0007

摘要

本研究主要利用地下水位歷線與沉陷檢測資料，配合水井普查統計資料及土層材質與組織結構等相關資料，用以推求壓縮指標C(下標 C)以及滲透係數K。研究範圍僅侷限於受壓飽和含水層，此層之土壤組織大多以砂和礫石為主。藉由構建地層下陷近，Q=-A(下標 soil)∂h/∂t取代抽水量難以估算的瓶頸，∂h/∂t為地下水位變率，受壓飽合和含水層水平面積A(下標 soil)之估算採用徐昇氏多邊形法。推求壓縮指標C(下標 C)以及滲透係數K的範例，應用在屏東及雲嘉地區等16個觀測站。壓縮指標C(下標 C)之計算結果顯示，「細砂」約略分佈在0.064~0.1；「粗砂」在0.034~0.064的範圍內；「礫石」則在0.034以下。K之計算結果，大致符合實驗室透水試驗各土層材質的試驗數據。藉由分析比較C(下標 C)及K的變異數σ^2，判斷此二係數的離散程度。並考慮地下水位歷線相關因子(h(下標 ave)、∆h(下標 max)、∂h/∂t)以及沉陷檢測資料H'對於C(下標 C)及K之影響分析。

關鍵字

地下水位歷線 ； 壓縮指標 ； 滲透係數 ； 受壓飽和含水層 ； 地層下陷

並列摘要

The object of this study is to investigate the Compression index C(subscript C) and the Permeability K in groundwater. The analysis is based on the information of the groundwater hydrographs, detected data of land subsidence, groundwater well investigation and the related data of land soil. The current project is restricted to confined saturated aquifer and the composition of this layer is mostly sand and gravel. The estimation of C(subscript C) and K is based on the analytical solution of the approximate model of land subsidence. However, Q=-A(subscript soil)∂h/∂t is used to solve the difficulty in estimating the pumping discharge, the groundwater level rate is computed by ∂h/∂t, and the horizontal surface area of confined saturated aquifer A(subscript soil) is estimated by the Thiessen polygons method. The estimations of Compression index C(subscript C) and the Permeability K are applied to 16 sites in Pingtung, Yunlin and Chia-yi regions. The results of these sites show that the value of C(subscript C) is 0.064~0.1 for the fine sand, 0.034~0.064 for the coarse sand, and below 0.034 for the gravel. However, the computed value of K is almost the same with the experimental result of Permeability test. The diversity of C(subscript C) and K can be determined by analyzing their variance (σ^2). The impact analysis on C(subscript C) and K also take into consideration in this study, especially with the correlate factors of groundwater hydrographs (h(subscript ave), ∆h(subscript max), ∂h/∂t) and detected data of land subsidence (H').

並列關鍵字

Groundwater hydrographs ； Compression index ； Permeability ； Confined saturated aquifer ； Land subsidence