| 摘要: |
| 为了降低水流对并线桥墩周围河床的局部冲刷掏蚀，本研究提出了一种放置于桥墩上游的拟树桩群防护结构，并分别通过模型试验和数值仿真的方法研究了拟树桩群布设距离L、叶面积比S和宽度W对桥墩周围河床冲淤特性的影响。研究结果显示，数值计算结果与试验结果具有良好的吻合度。拟树桩群能够有效降低桥墩周围的流速，削弱水流的冲刷作用，并促进悬浮泥沙的沉积，有利于桥墩群的稳定。防护存在时的悬浮泥沙沉积量和河床泥沙冲刷量分别是无防护时的3.11倍和0.22倍。拟树桩群的L、S和W的增加会使悬浮泥沙的沉积量明显增加，但对河床泥沙冲刷量的影响较小。在流速为0.48 m·s?1、含沙量为2.7 kg·m?3的条件下，根据桥墩上下游的淤积高度随L、S、W的变化得出，拟树桩群对并线桥墩防护效果最优的参数组合为：L=D、S=0.148、W=7D。 |
| 关键词: 桥墩局部冲刷 含沙水流 拟树桩群防护 泥沙冲淤变化 数值仿真 |
| DOI： |
| 分类号:TV142 |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| The investigation of local scour around bridge piers group based on the protection of quasi-stumps group |
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ZHANG Yi-sheng1, TANG Wei1, CAO Fei2, YAO Guang2, QI Wan-shuai3, CAI Ying-chun1
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1.School of Water Conservancy and Transportation,Zhengzhou University;2.Henan Province Highway Engineering Bureau Group Co.,LTD;3.Henan Puze Expressway Co.,LTD
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| Abstract: |
| A protective structure called quasi-stumps group placed upstream of bridge piers was proposed in this study in order to effectively reduce local scour of riverbed around the group of bridge piers. The influences of the layout distance (L), ratio of leaf area (S), and width (W) of the quasi-stumps group on the erosion and deposition characteristics of riverbed around the bridge piers are investigated through model experiments and numerical simulations. The research results show a good agreement between the numerical calculations and experimental results. The quasi-stumps group can effectively lower the flow velocities around the piers, weaken the erosion of the riverbed by the flow, and promote the deposition of suspended sediment, which is beneficial to the stability of the bridge piers group. The quantity of suspended sediment deposition and the quantity of sediment scoured from the riverbed under the presence of the protection are 3.11 times and 0.22 times of those without the protection, respectively. Furthermore, the increase of L, S, and W of the quasi-stumps group significantly enhances the deposition of suspended sediment, but has a little effect on the scour of sediment in the riverbed. Under the condition of flow velocity of 0.48 m·s?1 and sediment concentration of 2.7 kg·m?3, according to the variation of deposition height upstream and downstream of piers with L, S and W, the optimal parameter combination of the protective effect of the quasi-stumps group on piers is: L=D, S=0.148, W=7D. |
| Key words: local scour of bridge piers silt-carrying flow the protection of quasi stumps group erosion and deposition changes of sediment numerical simulation |
