外文翻譯---土石壩的特征及筑壩技術(shù)控制-在線瀏覽
2024-10-02 17:10本頁面
【正文】 3. top width The width of the earth dam top is generally controlled by the required width of fill for ease of construction using conventional equipment. In general, the top width should not be less than 30 ft. if a danger exists of an overtopping wave caused either by massive landslides in the pool or by seismic block tipping, then extra top width of erosion resistive fill will be required. The alignment of an earth fill dam should be such as to minimize construction costs but such alignment should not be such as to encourage sliding or cracking of the embankment. Normally the shortest straight line across the valley will be satisfactory, but local topographic and foundation conditions may dictate otherwise. Dams located in narrow valleys often are given an alignment which is arched upstream so that deflections of the embankment under pool load will put the embankment in pression thus minimizing transverse cracking.5. AbutmentsThree problems are generally associated with the abutments of earth dams: ① seepage, ②instability, and ③transverse cracking of the embankment. If the abutment consists of deposits of pervious soils it may be necessary to construct an upstream impervious blanket and downstream drainage measures to minimize and control abutment seepage. Where steep abutments exist, especially with sudden changes of slopes or with steep bluff, there exists a danger of transverse cracking of the embankment fills. This can be treated by excavation of the abutment to reduce the slope, especially in
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