In this project, the undercut still

In this project, the undercut stilling basin is adopted. In order to facilitate the construction, the stilling basin bottom plate is made of equal thickness. In order to reduce the seepage pressure at the bottom of the apron, a vertical drainage hole can be set under the apron, and a reverse filter layer can be laid at the bottom of the apron. The drainage hole is set at the back half of the horizontal floor plate, with a diameter of 10cm and a spacing of 2.0m, arranged in a quincunx shape. The thickness of the inverted filter is 30cm, divided into three layers, from top to bottom are 10cm gravel, 10cm medium sand and 10cm coarse sand.The width of the head end of the stilling basin is 92.5m, the diffusion angle of the stilling basin is set to 10 °, and the width of the end of the stilling basin is 100.7m.See Figure 5-2 for the structural dimension of stilling basin.