高水头抽水蓄能电站蜗壳座环安装要点

Installation points of spiral case stay ring for high-head pumped storage power station

绩溪电站蜗壳设计压力10.3MPa,采用国产800MPa级高强钢板卷制焊接而成。结合高强钢蜗壳座环材质特性和结构特征,以现场实际安装过程为基础,叙述蜗壳座环工地组圆拼焊、机坑内吊装调整、15.45MPa水压试验、5.15MPa保压浇筑及座环基础螺杆拉伸的详细流程;举例分析水压试验过程中的蜗壳变形量;简要计算绩溪电站多工况下座环基础螺杆应力变化情况,并复核基础螺杆预紧力安全裕量;总结高强钢蜗壳座环焊接过程变形量控制、保压浇筑前固定方式、基础螺杆拉伸工艺等安装要点。

For the Jixi Pumped Storage Power Station,the spiral case has a design pressure of 10.3 MPa and is made of China-made 800 MPa high-strength steel plates through rolling and welding.Based on the material and structural characteristics of high-strength steel spiral case stay ring,and on the basis of on-site actual installation process,this paper describes the detailed process of on-site assembling and welding of spiral case stay ring,hoisting and adjustment in pit,15.45 MPa hydrostatic pressure test,concrete placing under 5.15 MPa pressure,and foundation screw stretching of stay ring.Furthermore,this paper also analyzes with examples the deformation of spiral case during hydrostatic pressure test,briefly calculates the stress change of foundation screw of stay ring under several operating conditions of the Jixi Pumped Storage Power Station,checks the safety margin of pre-tightening force of foundation screw,and summarizes the installation points such as deformation control during welding of high-strength steel spiral case stay ring,fixing method before concrete placing under pouring,and foundation screw stretching process.