光滑陡坡泄槽上大颗粒泥沙运动特性试验研究

Experimental Study on the Movement Characteristics of Large Particle Sediment on Smooth Discharge Chute

基于室内不同粒径的大颗粒泥沙概化模型,通过不同影响因素的对比试验,采用摄像技术对大颗粒泥沙的跳跃轨迹进行记录,观察了大颗粒泥沙在陡槽上的运动情况。结果表明:当水深超过临界水深时,大颗粒泥沙将不再跳跃,且随着粒径的增加,临界水深逐渐变大,临界水深约等于粒径;通过分析卵石跳跃的特性可知,当粒径与坡度一定时,水深与卵石的跃高、跃长呈负相关;当水深、坡度一定时,粒径与跃高、跃长呈正相关;当水深、粒径一定时,随着坡度的增加,跃高变小,跃长增加;跃高、跃长和粒径的倍数关系k、m与水深、粒径呈负相关。试验结论将对泄水建筑物的防护设计提供一定的参考依据。

The comparing experiments of different influence factors were conducted on the basis of the conceptual model test of various large particle sediment. Thus the movements of large particle sediment were investigated by using photography technology to record the skip trajectory. The results indicated that once the water depth exceeded the critical condition,the sediment will no longer jumping. What'more,the critical depth increased with the increase of grain diameter,the critical depth approximately equal to the grain diameter. Meanwhile,according to the characteristics of jumping pebble,under a certain grain diameter and gradient,the depth had a negative power function relationship with the saltation height and length. Whereas, under the same depth and gradient,there was a positive power function relationship between jumping height,length and particle size. Besides,when the water depth and particle size are certain,with the increase of gradient,the jumping height decreased,and the jumping length increased. In addition, the jumping length and height had a multiple relations with the particle size and all showed a negative correlations with the water depth and the grain diameter. The experimental conclusions will provide certain reference frame to the design of outlet structures.