导流洞改建旋流式泄洪洞研究与应用

我国大多数导流洞为城门洞形断面，若改建旋流洞需要改成圆形断面，致使二期工程量大幅度增加，不经济。结合公伯峡水电站导流洞改建旋流式泄洪洞试验研究，采用收缩墩形成水垫塘的技术，大大缩短旋流洞的长度，同时增加消能力度，使泄洪洞的消能率达85%以上，流速降至15m/s以下，可防止洞内空蚀和下游冲刷，雾化现象，为导流洞改建旋流式泄洪洞的推广应用开辟了新的途径。

Test and study on the rebuild of diversion tunnel into gyrating current flood-releasing tunnel

Most of diversion tunnels in our country have the cross section of upper semi circle and lower square so that when the diversion tunnel is rebuild into a gyrating current flood releasing tunnel, its cross section should be changed into a circle section, which results in increasing greatly the engineering quantities in the second stage and is non economical. In combination with the test and study on the rebuild of diversion tunnel into gyrating current flood releasing tunnel in the Gongboxia Hydropower Station, this paper puts forward the use of converging hole plug to form water cushion pond that can greatly shorten the length of gyrating current tunnel, remove the negative pressure in the tunnel and increase the capacity of energy dissipation. With this technology, it can enable the energy dissipation rate of flood releasing tunnel to be up to over 85% and its velocity can be reduced to be less than 15 m/s so that it can prevent the tunnel from cavitation and the downstream from scour and atomization, which provides a new way for the application and popularization of the rebuild of diversion tunnel into gyrating current flood releasing tunnel.