一、概述二滩大坝为拋物线型混凝土双曲拱坝。为了满足施工后期导流、泄洪和放空水库的要求,需在坝体的三个不同高程上各布置一排孔口,分别称为表孔、中孔和底孔。各排孔口均以径向对称布置在拱冠线的两边(图1)。孔口的几何参数如下表。 First, an overview Ertan dam parabolic concrete double curvature arch dam. In order to meet the requirements of diversion, flood discharge and emptying reservoirs at the late stage of construction, an array of orifices are arranged on three different elevations of the dam body, namely the surface hole, the middle hole and the bottom hole respectively. The rows of orifices are arranged radially symmetrically on either side of the crown line (Figure 1). The geometric parameters of the orifice are shown in the following table.