桥墩冲刷坑动态冲刷过程研究

Study on scouring process around bridge pier

基于超声波地形仪,提出了桥墩冲刷坑超声动态测量方法,实现了桥墩冲刷坑水下实时非接触测量。结果表明,桥墩冲刷首先发生在墩侧及墩前,之后墩后逐渐开始冲刷,墩后沙丘缓慢发展;最大冲刷深度开始位于墩前,逐渐移至墩侧;桥墩前缘和两侧冲刷坑较深,桥墩后方冲刷坑较浅;各断面输沙率与上游断面泥沙输运及断面间泥沙冲淤有关。

An approach of ultrasonic dynamic measurement for the scour hole around bridge pier is proposed by an ultrasonic topographic instrument,and real-time non-contact observation of the scour hole around bridge pier underwater is realized.The results show that the scour appeared in the sides and the front of bridge pier firstly,and then the scour hole behind the bridge pier becomes larger.The dunes behind the bridge pier devel- oped slowly.The maximum scour depth begins in front of the bridge pier and gradually moves to the bridge pier sides.The scour holes in the sides and in front of bridge pier are deep,while the scour hole behind the bridge pier is shallow.The sediment transport rate of each cross-section is related to the sediment transport of the upstream and the scour or deposition between the cross-sections.