堰塞坝泄流槽断面型式离心模型试验研究

Centrifugal model tests on section form of drainage channel of barrier dams

基于唐家山堰塞坝坝料级配曲线,针对梯形、三角形和复式断面3种泄流槽断面型式,开展了堰塞坝漫顶溢流离心模型试验研究。分析不同除险断面型式对堰塞坝的泄流过程、总泄流量以及泄流后残留坝体几何尺寸的影响规律,并从水动力学的角度,对该泄流过程中泄流槽不同部位的水流特征进行了研究。试验结果表明,复式断面泄流槽不仅在初期泄流效率高、峰值流量小,而且残留坝体较低,总下泄水量最大,流量过程曲线具有"矮胖型"的特征,可迅速、最大程度的降低堰塞湖水位,同时能够有效的减轻因堰塞坝泄流给下游河道造成的防洪压力,是一种相对安全、高效的堰塞坝除险处置方法。

The centrifugal model tests on barrier dams overtopping are carried out based on the grain composition of Tangjiashan landslide dam, and the influence laws on the discharge process, released water and the size of the residual dam section of the drainage channel with trapezoid, triangle and compound forms are acquired. The characteristics of the flow in different parts of the channel during the discharge process are analyzed from the point of view of water dynamics. The results show that the compound section form has the characteristics of higher initial discharge efficiency, lower peak flow, higher residual dam and larger released water, in which the flow curve is ＂chunky-type＂. It can decrease effectively the pressure of flood protection caused by barrier dam discharge and reduce the water level greatly in a shorter time. It is an effective and safe method for the emergency handling of barrier dams.