水下不分散混凝土抗冲刷临界流速和凸起障碍物影响

针对水下不分散混凝土抗冲刷性能,开展室内模型试验,得出8种典型抗分散剂掺量条件下水下不分散混凝土的抗冲刷临界流速。基于OpenFOAM的有限高度圆柱绕流三维数值模拟,分析凸起障碍物对水下不分散混凝土局部冲刷的影响机制。结果表明,增加抗分散剂掺量和减少单位用水量可以提高水下不分散混凝土的抗冲刷性能,HF-III型抗分散剂的效果比UWB-II型抗分散剂的抗冲刷效果好;凸起障碍物周围以及下游易发生局部冲刷;与松散沙床上圆柱周围的冲刷坑相比,水下不分散混凝土的冲刷坑范围较小,深度较浅,且主要位于圆柱的下游。

Critical flow velocity for anti-scouring of non-dispersive underwater concrete and effect of exposed obstacle

Aimed at the anti-scouring ability of non-dispersive underwater concrete,we carry out a series of indoor flume tests,and obtain the onset flow velocity for anti-scouring of non-dispersive underwater concrete with 8 representative compositions of anti-washout agent.Based on 3D numerical simulations of flow around a finite cylinder using OpenFOAM,we analyze the effect mechanism of exposed obstacle on the local scouring of non-dispersive underwater concrete.The results show that the anti-scouring ability of non-dispersive underwater concrete increases with the amount of anti-washout agent,but decreases with the watering quantity.The HF-III anti-washout agent is better than UWB-II anti-washout agent in reducing scouring.The local scouring easily exists near the exposed obstacle and downstream.Compared with the scour holes around cylinder on loose sand bed,the scour holes on non-dispersive underwater concrete are smaller and shallower,and mainly located downstream of the cylinder.