吉沙水电站高压钢岔管外包混凝土的受力研究

Study on the Stress of High-pressure Steel Bifurcation Concrete Encasement in Jisha Hydropower Station

吉沙水电站引水系统采用对称"Y"形内加强月牙肋型钢岔管,分岔角为70°。设计内水压力约652.2 m水头,按明管设计,岔管布置在洞外,采用明挖回填,外设钢筋混凝土镇墩。由于施工原因,造成岔管主体一部分位于山体内,一部分位于洞外,使岔管外围约束不连续。为此,对岔管、外包混凝土及围岩整体进行了三维有限元计算分析,对不同边界条件下的受力状态进行了比较系统的计算研究和总结,以供岔管实际运行期分析参考。

The symmetrical Y-type steel bifurcation with crescent rib is used in the diversion system of Jisha Hydropower Station. The branch angle is 70°, and the bifurcation is designed on the condition of exposed arrangement and with internal water head of about 652.2 m. The main body of bifurcation is arranged in diversion tunnel, and two branches are arranged outside the diversion tunnel and supported with reinforced concrete anchorage block. Because the actual construction does not meet the design scheme, the completed bifurcation is affected by discontinuous external constraints. The stresses of bifurcation, concrete encasement and tunnel surrounding rock under different boundary conditions are analyzed by three- dimensional finite element method. The results provide a reference to the actual operation.