Stepped upstream head wrapper for longitudinal cofferdam

Abstract

The invention discloses a stepped upstream head wrapper for a longitudinal cofferdam. The stepped upstream head wrapper comprises a cofferdam connecting section and a step platform, wherein the cofferdam connecting section is located above a longitudinal cofferdam main body and is connected with the longitudinal cofferdam main body, the step platform is lower than the cofferdam connecting section in height, the front end of the cofferdam connecting section is sloped to the step platform and is connected with the step platform, and the edge of the step platform is also downwardly sloped, so that a head wrapper structure with two steps is formed. When a water level is lower, water flow can flow through a lower sloped section of the step platform naturally; and when the water level of a flood overflows the step platform, due to the existence of the step platform, the head wrapper yields most space to flow through the water flow, so that lower parts of lap joints of the longitudinal cofferdam and a transverse cofferdam are prevented from being impacted by oversized water flow, the generation of strong around-streaming is avoided, and the overflowing capability of open channels is improved. According to the stepped upstream head wrapper for the longitudinal cofferdam, the overall height of the cofferdam is greatly reduced, the investment of an engineering construction period is reduced, and the structure is firm, so that the stepped upstream head wrapper can be applied to hydraulic engineering construction.

Description

technical field [0001] The invention relates to a cofferdam in water conservancy project construction, in particular to a wrapping head in the cofferdam. Background technique [0002] In the construction of water conservancy projects, in order to build permanent water conservancy facilities (such as sluices, power stations and ship locks) under dry land conditions, it is necessary to first build temporary maintenance structures in the water, which are cofferdams. The more commonly used cofferdams are earth-rock cofferdams. In order to prevent water and soil from entering the construction site, earth-rock cofferdams need not only good anti-sliding stability, but also sufficient anti-seepage measures to better block The river water outside the cofferdam does not enter the foundation pit of the cofferdam. [0003] According to the relationship between the axis of the cofferdam and the direction of water flow in the river, the cofferdam arranged in the same direction as the wat...

AI Technical Summary

Problems solved by technology

[0005] For large-scale sluice projects, in the actual phased construction diversion process, it often happens that due to the straight or oblique design of the upstream wrapping head of the longitudinal cofferdam, the water flow at the upstream inlet of the diversion open channel occurs near the wrapping head. The strong circumvention flow pattern produces a series of vortices, and the vortex zone occupies the effective open channel water flow area, resulting in a decrease in the flow capacity of the entire diversion open channel, and the measured value of the upstream water level is significantly higher than the design calculation value, so that the cofferdam The overall height must continue to increase, increasing the project investment

In general, the existing two types of vertical cofferdam upstream wrapping head types, straight line and oblique line, often lead to insufficient flow capacity of open channels during the construction and diversion of large-scale sluice projects, and the water level rises, thereby increasing the project size. invest

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