圖書典藏及影音數位平台

河川砂石主要來自於上游集水區邊坡崩落下移河道之土石，因水系內各邊坡岩土層結構不一，其所產生之河床材質種類相當繁多，依其材質特性可分別作為營建用之粗細骨材、基地回填、農地改良等不同之使用，此外河川砂石性質與河川疏濬標售效益亦息息相關，故為適度且有效妥善利用河川有限之砂石資源，實有必要廣泛調查河川砂石性質，俾利辦理相關工程及疏濬之參考，及提供未來河川砂石合理開發及分配之依據，並達到資訊公開化之目標，爰成立本計畫調查高屏溪、曾文溪、大安溪、大甲溪及烏溪等水系之河床砂石材質。

Aggregates on rivers are mainly earth and stone that drop down from the side slope of water gathering ground in upriver to the river course. Because the structures of rock and soil layers on the side slope of river systems vary, the types of aggregates on riverbed produced by it are various. In the moderate and effective plan for the using of sand resources according to its material characteristics and economic value, it is necessary for us to extensively investigate the property of aggregates on rivers, in order to provide reference for relevant dredging engineering, the reasonable development and distribution of aggregates on rivers in the future and achieve the aim of information disclosure. The research investigates the property of aggregates in a total of 125 sites in such rivers as: Gaoping River, Zengwen River, Daan River, Dajia River and Wu River. According to the specification corresponding to the applicable use of different aggregates, items including aggregate proportion, water absorption, and Los Angeles abrasion ratio and soundness property are appraised to divide the quality of aggregates into three grades. Aggregates with the first grade quality are hardest and applicable to high strength concrete or special work; aggregates with the second grade quality are applicable to common concrete and asphalt concrete according to CNS standard; aggregates with the third grade quality have low strength, used as backfill materials and applicable to road grading or agriculture use. The upriver stratum of Qishan River, the branch of Gaoping River, contains sandstone and shale. The sampling result shows the quality of rock above Gaopingxi Bridge belongs to the first grade. Slate and quartzite exist in the mountain area of Laonong River, and they are hard. But the joints in upstream section are developed, so the quality of rock from Xinwei Bridge to Ligang Bridge is high and belongs to the first grade, but the quality above Xinwei Bridge is poor and belongs to the second grade. Most of the rocks in Ailiao River consist of black argillite, slate and phyllite and dark grey greywacke, which have low hardness and belong to the quality of second grade. The rock stratum of Zengwen River mainly constitutes argillaceous sandstone and siltstone. The river basin contains few coarse aggregates, which belong to the third grade. Coarse aggregates exist above Erxi Bridge, and the quality of aggregates belongs to the second grade. The upper stream of Daan River contains argillite in upper part and black and hard argillite and shale in the majority and the rest are sandstone, shale and gravel layer. The quality of aggregates in the whole section is high and belongs to the first grade. The stratum in the mountain area of Dajia River mainly constitutes argillite, slate, phyllite and greywacke. The rocks are hard, and the sampling result shows aggregates in the whole section belong to the first grade. The upper stream of Wu River mainly consists of the alternating layers of argillite, slate, phyllite and greywacke with hard texture. But Wu River has many branches, and the stratum adjacent to it contains modern platform stack layers and modern alluvium, so the property of aggregates in the main branches is different slightly, but most of them have the first grade class. Except for considering differences in the quality of aggregates in different areas, the adjustment of use fee in adopting aggregates in rivers and public land shall consider load distance and the content of aggregates. The research evaluates the mean distance between the place of dredging rivers and vital communication line, and the content of aggregates shown in the test result obtained from sampling site of rivers, and it also considers the factor of quality grade. The adjustment coefficient of use fee in adopting aggregates in rivers is calculated through weighting calculation. The adjustment coefficient of rivers evaluated in this research can also serve as the regulation for aggregate subscription in dredging and the principle for the auction and treatment of aggregates as well as the reference in determining the base price of auction.