桐子林水电站明渠导流方案优化研究

Optimization of Open Diversion for Tongzilin Hydropower Station

欠宽阔覆盖层河道采用明渠导流宣泄大流量时,施工度汛所面临的水力学问题突出。对桐子林水电站导流明渠3种布置方案进行了系统模型试验。研究表明:底宽44 m明渠方案出口流速高达17 m/s,消能防冲难度极大,采用钢筋石笼和四面体防护失事风险很高;若在明渠末端增加消力池,由于明渠水流弗氏数Fr<1.5,消能效果无法提高,明渠出口流速仍达13 m/s;结合闸坝地基采用地下连续墙加固等措施,可将明渠宽度增加至62 m,明渠出口流速减小至10 m/s,钢筋石笼和四面体稳定性大大提高,能够有效解决明渠出口消能防冲问题。试验表明,采用宽明渠方案是解决大单宽流量明渠出口下游消能防冲的有效方法。

As a narrow river bed and a larger discharge,the diversion of Tongzilin Hydropower Station with open channel will face serious problems in flood season.Models for three diversion layouts were tested.For scheme I,the maximum outlet flow of channel with a width of 44 m is 17 m/s,energy dissipation is extremely difficult and the accident risk is high even using reinforced stone cages and tetrahedrons to protect downstream bed.For scheme II with a still basin in the end section of the channel,the maximum outlet flow is still reached to 13 m/s,and energy dissipation can not be improved significantly as the Froude number of channel flow is less than 1.5.For scheme III with a combination of gate dam foundation using underground continuous wall,the outlet width of channel can be increased to 62 m and the maximum outlet flow can be reduced to 10 m/s,the reinforced stone cage and tetrahedrons is stable,and the energy dissipation and the erosion protection can be solved effectively.