The spur dikes are widely applied in marine and estuarine engineering projects, and its surrounding local sediment scouring and silting characteristics directly affects the safety and stability of the project. Existing studies primarily rely on physical experiments or empirical prediction formulas, lacking a deep understanding of the flow structure and sediment transport patterns. Based on the software Delft3D, this paper presents a numerical simulation of the local sediment scouring and silting characteristics of spur dikes under clear water conditions and performs reliability verification. The sediment scouring and siltation characteristics of single dam and spur dike are compared. The diversion characteristics, local bed shear stress and local sediment scouring and siltation patterns of the spur dikes are analyzed, and the impact of dam length and flow velocity is discussed. The results show that the when the spur dike spacing decreases by 40 m, the maximum dimensionless shear stress increases from 2.56 to 7.48. An increase of flow velocity further expands the flow diversion range and the density of streamlines, with the maximum dimensionless shear stress rising from 3.17 to 5.60; The increase is approximately 76.7%, and the area percentage of high shear stress zones increases from 20.27% to 34.44%. Additionally, when the spur dike spacing is reduced by 20 m, the maximum scour value at the dam head increases by approximately 45.89% to 59.92%; When the flow velocity increases, the maximum scour value increases by about 13.41%, while the scour pit area expands and the sediment deposition area spreads. This study can provide theoretical support for optimizzation design of spur dikes.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |