通过在桥梁下游设置拦沙坝可减缓上游桥梁冲刷.以典型工程为原型制作物理模型,选取进口流量Q、拦沙坝坝顶高程Z及拦沙坝距桥墩轴线距离L作为研究参数,开展了34组试验,结果显示各方案下,桥墩至拦沙坝间的一般冲刷比原河床低0.3 ~0.5 m,桥墩局部冲刷一般不超过5 m,桥墩冲刷坑下游约长25~35 m,为使拦沙坝不受桥墩冲刷坑影响,拦沙坝位置应选择在距桥墩中心线下游45 m左右,坝顶高程比坝址处河床高1.0~1.5 m.
Sand dredging in the river will result in headword erosion against the riverbed near the bridge.In order to understand the protection effect of sediment storage dam and the interaction bridge scouring, in the study, a physical model was made based on typical engineering, 34 groups of experiments were set, the inlet flow Q, the height of the dam height Z and the distance between the dam and the bridge pier are taken as the research parameters, and the flow field, water line and scouring under each working condition were analyzed.The results showed that in the case of sediment storage dam, the riverbed between the pier and the dam which was processed by general scouring was 0.3 to 0.5 m lower than the original riverbed, that maximum depth of local scouring around the pier was generally not more than 5 m, and that influence range of local scouring to the riverbed of the downstream was about 25 to 35 m.Therefore, the dam should be positioned in the place which is at least 45m far away from the downstream of pier axis and the dam crest elevation should be 1.0 to 1.5 m higher than the riverbed.