在中国现有最高的拱坝中,其溢流方式多数是溢洪道堰顶自由溢流。这是一种经济措施,但是①由于库容被限制在堰顶水位,相应于最大泄量的库容高度被浪费掉;②存在地基被破坏的危险。如果在现有溢流堰上安装自溃闸门(fuse gates)就可以经济地解决许多现有坝中的这两个问题,库容一般可增加 20％。如果要求不损失库容,可应用相同的系统增加现有溢洪道的过流能力。 In China’s tallest arch dam, most of its overflow modes are free overflow of the spillway weir. This is an economic measure, but ① the reservoir volume corresponding to the maximum discharge is wasted as the reservoir volume is confined to the crest level; and ② there is a risk that the foundation will be destroyed. These two problems in many existing dams can be economically solved by installing fuse gates on existing weirs, with a 20% increase in storage capacity. The same system can be applied to increase the over-current capacity of an existing spillway if it is required that no loss of storage capacity be required.