大头坝是本世纪初出现,40年代后得到推广的一种轻型坝.50年代以来我国也有一些工程采用这种坝型,其中单支墩的有桓仁坝、柘溪坝和那岸坝等. 不少单支墩大头坝在施工期就出现裂缝,如桓仁、柘溪坝和日本的大森川坝.蓄水后,有的表面裂缝发展为劈头裂缝.所谓劈头裂缝是指基本上沿着支墩的对称面从迎水面一直向支墩内部发展的裂缝. Dadu dam is a light dam that appeared at the beginning of this century and was popularized after the 40s. Some dam projects have been adopted in our country since the 1950s, among which there are Huanren dam, Baoxi dam and the dam Many single-pier dams appear cracks during the construction period, such as Huanren, Baoxi Dam and Japan’s Omori Dam. After water storage, some of the surface cracks developed into split-head cracks. The symmetry of the pier from the water facing the pier has been developed within the cracks.