Cofferdams are made by driving metal sheet piling into the Bed to form a watertight fence.
在近代工程中，筑围堰时一般先打下钢板桩以形成阻水层。
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Cofferdam: Watertight enclosure from which water is pumped to expose the Bed of a Body of water in order to permit the construction of a pier or other hydraulic work.