A Calculation Method of Local Scouring Depth of Bridge Piers on Bedding-silted Riverbed

Abstract

The invention discloses a method for calculating a local scour depth of a pier on a bedding deposition riverbed. The method comprises the following steps: firstly, analyzing and judging a target soil layer where a maximum scour depth arrives after a local scour pit of the pier is stable by comparing the relationship between calculated travelling flow velocities of soil layers and critical breakdown flow velocities of the soil layers; then calculating the local scour depth of the pier on the target soil layer through a local scour depth calculation formula of the pier on a single soil layer riverbed by adjusting such parameters as a calculated travelling water depth, the calculated travelling flow velocities, an initial flow velocity and an initial silt scour flow velocity of the silt of the target soil layer under the calculated travelling water depth; and finally, obtaining a final local scour depth of the pier on the bedding deposition riverbed in combination with the thicknesses of all soil layers at the upper part of the target soil layer. By adoption of the method disclosed, the difference of erosion resistibility of silt on different soil layers, the influence of the thickness of the upper layer soil to the scour of the lower layer soil, the scour features of soil layer boundary interfaces and the influence of the deposition sequence of the soil layers to the local scour depth of the pier are fully reflected.

Description

technical field [0001] The invention relates to the field of traffic engineering construction technology research, in particular to a calculation method for the local scour depth of bridge piers on a bed of bedding deposition structures. Background technique [0002] When studying the local scour of bridge piers, most studies are based on the fact that the riverbed is a single-graded sediment. However, for high-sediment rivers, when the water-sediment situation has the characteristics of large inter-annual changes in water volume and heterogeneous sources of water and sediment, due to the different characteristics of river sediment in different periods, it is easy to cause layered deposition of river bed sediment. For example, in the Yellow River in my country, observations in many river sections have shown that the riverbed is formed by bedding and silting, and there are significant differences between the sediments in each layer. Therefore, when analyzing the local maximu...

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Problems solved by technology

Therefore, when analyzing the local maximum scour of bridge piers for riverbed material bedding siltation river sections, if only the sediment properties of the riverbed surface are used to calculate and analyze the scour depth of bridge piers, the differences of sediment in different soil layers, soil thickness, The scouring characteristics of the soil interface and the influence of the soil layer deposition sequence on the local scouring depth of the bridge pier cannot fully reflect the actual scouring situation of the bridge pier

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