小浪底水利枢纽布置3条排沙洞,肩负着小浪底洞群进水塔的防淤堵和小浪底水库的排沙、部分泄洪的任务,其应用水头约120m。为防止衬砌在高压水作用下开裂,渗水进入山体,设计中采用了后张法无粘结预应力混凝土衬砌。3条排沙洞结构相似,均由进口渐变段、出口渐变段、进口弯曲段、标准洞身段、出口闸门、挑流鼻坎等组成,3条洞的全长为2856.5m,其中进口弯曲段长45.66m。不同的是:1号排 Xiaolangdi Water Control Project layout of three sand discharge tunnel, shouldering the Xiaolangdi Cave Group of anti-clogging tower and Xiaolangdi Reservoir Sediment discharge, part of the task of flood discharge, the application of about 120m head. In order to prevent lining cracking under the action of high pressure water, seepage into the mountain, the design uses post-tension method of unbonded prestressed concrete lining. The structure of the three sediment discharge tunnels is similar in structure, which is composed of the entrance gradient section, the exit transition section, the entrance curved section, the standard tunnel section, the exit gate and the pick-up nose ridge. The total length of the three holes is 2856.5m, Length 45.66m. The difference is: No. 1 row