乌东德水电站水垫塘护坡板块结构型式试验研究

Experimental study on structural pattern of slope protection slab for cushion pool of Wudongde Hydropower Station

为解决高坝泄流引起的水垫塘内部水流紊动导致其结构破坏问题,针对乌东德水电站护坡不护底水垫塘的防护结构,依托乌东德水电站整体模型,考虑止水局部破坏的最不利工况,分别对排水失效、封闭自排、封闭抽排等三种板块结构型式进行了水力学试验研究,分析了不同板块型式对护坡板块背水面和迎水面时均压强、脉动压强以及脉压相关性的影响。结果表明:(1)相比排水失效板块,封闭自排和抽排板块对脉压的影响较小,但均能有效降低板块内外侧时均压强差,使最大时均压强差保持在0.4 m水头以下;(2)封闭自排板块能有效改善水位波动区板块内外侧脉压的同步性,提高脉动压强互相关系数;(3)抽排廊道的开挖对两岸岩体有削弱作用,可能对地下厂房不利。研究所得结构为水垫塘护坡设计和安全运行提供参考。

In order to solve the problem of the structural damage caused by the water turbulence in the cushion pool due to the discharge from high dam,the hydraulic experimental studies are respectively made on three kinds of structural patterns of the slab for the slope protection,i. e. drainage-failure,sealed and self-drainage and sealed and pumping-drainage,for the protective structure of the cushion pool with slope protection and without bottom protection for Wudongde Hydropower Station in accordance with the integral model of the hydropower station under the consideration of the most unfavorable operation condition of the local damage of the water-stop therein,in which the impacts from different patterns of the slab on the time-average pressure intensity,fluctuating pressure intensity and the correlation of the fluctuating pressure of both the downstream face and the upstream face of the slab are analyzed as well. The result shows that（ 1） compared with the slab of drainage-failure,the impacts from the slabs of sealed and self-drainage and sealed and pumping-drainage on the fluctuating pressure are less,both can effectively reduce the difference between the time-average pressure intensities of both the sides of the slab and then make the maximum time-average pressure intensity remain below the water-head of 0. 4 m;（ 2） the slab of sealed and self-drainage can effectively improve the synchronism between the fluctuating pressures of both the sides of the slab in the water level fluctuating zone and then increase the correlation coefficient of the fluctuating pressure intensities;（ 3） the excavation of the gallery for pumping-drainage has the effect to weaken the rock masses on both the banks and then is possibly unfavorable to the underground powerhouse. The structure obtained from the study can provide references for design and safe operation of the slope protection of cushion pool.