| 摘要: | 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. |
