过水围堰挑压坎楔形护板水力特性

该文基于过水围堰混凝土楔形护板溢洪分析,提出在尾部设置平台形成挑压坎楔形护板。采用紊流数值模拟方法,对挑压坎楔形护板水力特性进行了研究,并与一般楔形护板对比分析。研究表明:挑射流可以提高堰面的消能效果,特别在小洪水工况时改善较为明显;冲入消能平台的流速有所降低,可减小水流对堰脚的冲刷;水流经挑压坎以平抛射流的形式向下弯曲,能增加水体作用于下一级护板的稳定力。一般楔形护板只在首部附近出现一个压力最大值,挑压坎楔形护板首、尾各有一个压力峰值,可以改善护板的受力条件,有利于过水围堰的整体稳定。

Hydraulic characteristics on wedge slab with flip bucket of overtopped cofferdam

Based on the overflow analyzing of concrete wedge slab of overtopped cofferdam,a new wedge slab with flip bucket was proposed by setting tail platform.The hydraulic characteristics of the wedge slab with flip bucket were calculated and analyzed by turbulent numerical simulation,and compared with general wedge slab.It shows that the flip flow can improve the energy dissipation effect of protective facing,especially in small flood condition.The flow velocity entering energy dissipation flat-form decreases comparing with general wedge slab,which is good to relieve the flow scour of weir feet.The horizontal flip flow bends down passing flip bucket,which can increase the stabilizing force of the upper slab acting on the lower.There is only a maximum pressure at the head of general wedge slab.Two pressure peaks respectively appear at the head and tail of wedge slab with flip bucket,which can improve the force condition of protective facing and favor the overall stability of overtopped cofferdam.