Wedge cone and its construction method in the stagnant area of ​​river confluence

Abstract

The invention discloses a riverway intersection water flow stagnant area wedge cone. According to a building method of the cone, under the main and branch water flow incoming representative flow condition, SMS numerical value simulation software is utilized for calculating a two-dimensional flow velocity field of a main and branch water flow intersection area under the natural terrain condition, flow velocity contour maps at the different water level elevation positions are extracted, contour lines equal to the sediment incipient motion critical flow velocity Uc in the different water level elevation flow velocity contour lines are determined through the sediment incipient motion critical flow velocity Uc, and the contour lines are overlapped to form a wedge cone structure; a connection line of flow velocity contour line intersection points with the main and branch water flow velocity equal to the Uc in the lowest water level process and shoreline intersection points is defined as a y axis, section subdivision is carried out on the stagnant area along the y axis, water levels of the contour lines on the section are extracted to be fitted, the section water levels meet a parabolic equation that z is equal to a ax<2>+bx+c, section modulus a, b and c build a relation with the y axis, and the structural terrain elevation of the wedge cone is obtained. The wedge cone can effectively reduce the jacking effect of the intersection area, the water flow in the intersection area is uniform, and the wedge cone is suitable for the flow rectification engineering of the intersected riverway water flow stagnant area

Description

technical field [0001] The invention belongs to the technical field of a river confluence water flow rectification method and its construction, in particular to a wedge cone in a river confluence water flow stagnation area and a construction method thereof. Background technique [0002] The water system evolution of natural rivers and measures such as drainage and sewage discharge in water conservancy projects often form the intersection mode of trunk and branch rivers. At the confluence of rivers, the two streams support each other, and the mixing is strong, and the characteristics of the water flow in the confluence area become very complicated. When the tributary water and sediment enter the mainstream, the original water-sediment balance will be broken, and an obvious water flow separation zone will be formed downstream of the confluence area, resulting in sediment deposition in the separation zone; after the tributary flows into the confluence mainstream, the mainstream...

AI Technical Summary

Problems solved by technology

From the confluence phenomenon of natural rivers, it can be seen that the sediment deposition in the confluence and stagnation area is roughly triangular in shape, and because the vertical distribution of the flow velocity in the channel is roughly logarithmic, the closer to the bottom of the bed, the smaller the flow velocity, and the flow velocity gradient with the inflow velocity The larger the stagnation zone, the greater the width of the stagnation zone formed in this way. At the same water depth, the smaller the flow velocity is, the larger the triangular area formed by the stagnation zone will be, which in turn will intensify the mutual jacking effect of the two streams, causing the water level in the intersection area to rise and the flow velocity to increase. The sediment will further fall and silt, forming estuary shoals or river middle shoals (islands), which will reduce the effective water flow area of ​​the river, seriously affecting the navigation and flood discharge capacity and the safety of buildings in the confluence area.

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