Combined cofferdam for sludge river bed and construction method of combined cofferdam

Abstract

The invention discloses a combined cofferdam for a sludge river bed and a construction method of the combined cofferdam. The combined cofferdam comprises a longitudinal concrete cofferdam body and twotransverse soil-rock cofferdam bodies, wherein the two transverse soil-rock cofferdam bodies are arranged between the two ends of the longitudinal concrete cofferdam body and a river bank. The construction method comprises the steps of construction of a temporary cofferdam, construction of the longitudinal concrete cofferdam body and construction of the transverse soil-rock cofferdam bodies. According to the construction method, a gabion facing layer and a stone facing layer are arranged on the upstream face of each transverse soil-rock cofferdam body, the water flow scouring resistance of the upstream faces of the transverse soil-rock cofferdam bodies is improved, and the phenomenon that a water body is polluted by muddy water because of scouring of rainwater and water flow is avoided. In the construction method, a bottom blocking structure and a vertical water-proof structure are directly constructed at a time, and due to the construction of a first seepage-prevention wall, the impermeability of the concrete cofferdam body itself is effectively increased; the first seepage-prevention wall and a second seepage-prevention wall are constructed by using a high-pressure chemical churning pile device so that setting of mixed cement grout can be rapid, it is avoided that the mixed cement grout goes away with the water flow before setting, and therefore, the aims of solidification and seepage prevention are achieved.

Description

technical field [0001] The invention belongs to the technical field of water conservancy project construction, and in particular relates to a mud riverbed combined cofferdam and a construction method thereof. Background technique [0002] The silt river bed is covered with a layer of silt on the river bed, and the thickness of the silt layer is relatively large, so it is difficult to excavate or support when the cut-off wall is constructed; the earth-rock cofferdam is a cofferdam made of earth-rock weirs. The earth-rock cofferdam can be combined with the closure dike, can use the excavation waste, and can directly use the excavation and transportation equipment of the main project for mechanized and rapid construction. It is the most widely used cofferdam form in my country. However, earth-rock cofferdams have low erosion resistance and occupy a large area, so they are generally used for horizontal cofferdams. Concrete cofferdams are often used in water conservancy projects...

AI Technical Summary

Problems solved by technology

[0005]2. The vertical waterproof structure of the earth-rock cofferdam in this combined cofferdam is built by the construction method of building section by section from bottom to top. If the waterproof structure needs to be filled with earth and rocks on both sides of the vertical waterproof structure of this section, the next section of vertical waterproof structure can only be built after the earth and rocks are filled to the height of the vertical waterproof structure of this section. Inconvenient question

[0006] 3. There is no anti-seepage structure at the bottom of the concrete cofferdam, and the concrete weir body is generally cast-in-place concrete. During the concrete pouring process, the silt on the river bed will affect the concrete pouring, and the concrete is prone to vibration during the pouring process. If it is not dense, it will affect its own impermeability

[0007] 4. During the construction of traditional anti-seepage walls, after the earth-rock mixture is filled into the water, its internal friction angle increases sharply, and the rocks accumulate unevenly, forming cavities and local seepage channels in the cofferdam body; and such as Custer There are a large number of melting grooves and melting grooves in riverbeds such as landform areas, and the density of filling bodies in the grooves is not good. When the high nozzle passes through these areas, the cement slurry is easily taken away by the water flow, resulting in leakage and non-returning of slurry, which is difficult to achieve. Consolidation and anti-seepage purposes

[0009] 1. The earth-rock cofferdam in the combined cofferdam has weak anti-water flow erosion ability

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