小浪底水利枢纽工程孔板泄洪洞设计

Design of the Orifices of the Xiaolangdi Multipurpose Dam Project

小浪底工程在世界上首次将导流洞设计改建成１４０ｍ高水头孔板泄洪洞。孔板泄洪洞由龙抬头段、孔板消能段、闸室前渐变段、中间闸室、闸室后洞身段、出口挑流段等部分组成，其中孔板消能段是泄洪洞的核心部位，设三级孔板消能。文中详细介绍了孔板泄洪洞的特点、孔板型式、消能原理、体形设计、结构设计以及为减少负压和防止水翅冲击弧形闸门支铰等难题而进行的创新设计。结合设计，给出了泄洪洞各组成部分的结构计算方法及结果。

In the Xiaolangdi Multipurpose Dam Project, the diversion tunnels were, for the first time inthe world. converted to energy dissipating flood release orifice tunnels at a head of 140 m. The orifice tunnel consists of a connector section, from the intake tower, an orifice ring section, a transitional section upstream of the gate, a mid-gate chamber section. a tunnel section downstream ofthe gate, an open channel flow section, and an outlet. Among them, the orifice ring section is thekey part. Three types of energy dissipating orifice baffles are installed in this section. Detail descriptions are given as follows, the characteristics of the orifice tunnel, type of the orifice ring.principle of energy dissipation, geometry of the orifice rings, structural design,and innovative design to reduce negative pressure and to keep spray away from sector gate hinge. Combined withthe design, calculation method and results are given for each component of the flood dischargetunnels.