Annular flat plate structure for protecting cofferdam toe
Technical Field
The invention relates to the field of cofferdam scour prevention, in particular to an annular flat plate structure for protecting a cofferdam toe.
Background
When buildings such as dams, piers, wharfs and the like are built in a river channel, cofferdams are often used as temporary water retaining buildings to form a dry ground construction foundation pit. A narrow riverbed water flow is formed after a cofferdam is built on a riverbed, the narrow riverbed water flow is a boundary layer separated flow caused by a protruding barrier appearing on a flow boundary, and meanwhile, as the area of a water passing channel is reduced, the flow velocity in the narrow riverbed is increased, vortexes and backflow appear near corners of a longitudinal cofferdam and a transverse cofferdam, the flow state is relatively disordered, so that not only can the riverbed be scoured, but also the slope feet of the cofferdam can be scoured, and the safety of the cofferdam is threatened. Especially, the hydropower station project is large in scale and long in flow guiding and construction time, and the quality and safety of the cofferdam are directly related to the quality and safety of the whole hydraulic engineering.
The existing cofferdam toe protection mainly adopts two modes of a guide wall and a throwing and filling bottom protection material (boulder, a steel reinforcement gabion and the like). The guide wall relates to underwater construction, and has higher cost and construction difficulty; the throwing and filling bottom protection materials are easy to deposit on the river channel, and are not beneficial to later-stage fishing. Therefore, an annular flat plate structure for cofferdam toe protection, which is convenient to construct and simple in structure, is urgently needed.
Disclosure of Invention
Aiming at the defects in the technology, the invention provides the annular flat plate structure for protecting the cofferdam toe, which has the advantages of simple construction, low cost, obvious anti-impact effect on the toe at the corner of the cofferdam, particularly the toe of the longitudinal cofferdam, and capability of protecting the cofferdam toe from being washed to cause cofferdam failure.
In order to achieve the purpose, the invention provides an annular flat plate structure for protecting cofferdam slope toe, wherein a cofferdam slope comprises a slope toe, the slope toe is arranged below a horizontal plane, an annular flat plate for buffering is horizontally arranged at an arc-shaped turning foot of the slope toe, the bottom of the annular flat plate is tightly attached to the upper surface of a riverbed, an embedded part is arranged on the inner side of the annular flat plate, the embedded part is embedded into the slope toe, the embedded part and the slope toe are of a fixed integrated structure, a water flow buffering part is arranged on the outer side of the annular flat plate, and the outer edge of the water flow buffering part is of the same structure as that of the slope toe and is of an arc-shaped bent structure; the cofferdam corner slope toe anti-scour effect is obvious, and the cofferdam slope toe is protected from being washed to cause cofferdam failure. Because of the annular flat plate at the toe of the cofferdam can adjust the water flow state and smooth the water flow, the direction of partial water flow is adjusted, the direct undercutting and scouring of the surface of the river bed at the toe of the cofferdam is avoided, and the scouring of the river bed surface at the toe of the cofferdam is reduced. Compared with the construction of the guide wall at the toe of the cofferdam, the annular flat plate can reduce the engineering quantity. The solid materials are cast and filled at the slope toe of the cofferdam, so that the river channel can be blocked, the fishing at the later stage is not easy, and the annular flat plate is convenient to detach and recover in the cofferdam. The annular flat plate has a simple structure and is convenient to design and construct. The embedded part and the slope toe are fixedly integrated, and instability and damage of the annular flat plate are prevented.
Preferably, the annular flat plate is made of a steel plate and has a thickness of 0.01 to 0.06 m. And a steel plate with better cold bending performance is adopted to resist the impact force generated by water flow.
Preferably, the water flow buffering part of the annular flat plate is arranged below a horizontal plane, and the width of the water flow buffering part below the horizontal plane is 2-3 m.
Preferably, the embedding part is provided with an anchoring device, and the anchoring device is used for fixing the embedding part and the toe. So as to reduce the steel plate material in the cofferdam.
Preferably, the width of the insertion portion is designed according to a stress analysis condition of the water flow buffering portion.
Preferably, the water flow buffering part comprises an arc buffering part and extension buffering parts arranged on two sides of the arc buffering part, and the ratio of the length of the extension buffering part on one side to the arc length of the arc buffering part is 0.5-1: 1.
Preferably, the height of the upper surface of the water flow buffering part is gradually increased along the direction approaching the toe.
The invention has the beneficial effects that: compared with the prior art, the invention provides an annular flat plate structure for protecting cofferdam slope toe, wherein a cofferdam slope comprises a slope toe, the slope toe is arranged below a horizontal plane, an annular flat plate for buffering is horizontally arranged at the arc-shaped corner of the slope toe, the bottom of the annular flat plate is tightly attached to the upper surface of a riverbed, an embedding part is arranged on the inner side of the annular flat plate, the embedding part is embedded into the slope toe, the embedding part and the slope toe are of a fixed integral structure, a water flow buffering part is arranged on the outer side of the annular flat plate, and the outer edge of the water flow buffering part is of an arc-shaped bent structure as same as that of the slope toe; the cofferdam corner slope toe anti-scour effect is obvious, and the cofferdam slope toe is protected from being washed to cause cofferdam failure. Because of the annular flat plate at the toe of the cofferdam can adjust the water flow state and smooth the water flow, the direction of partial water flow is adjusted, the direct undercutting and scouring of the surface of the river bed at the toe of the cofferdam is avoided, and the scouring of the river bed surface at the toe of the cofferdam is reduced. Compared with the construction of the guide wall at the toe of the cofferdam, the annular flat plate can reduce the engineering quantity. The solid materials are cast and filled at the slope toe of the cofferdam, so that the river channel can be blocked, the fishing at the later stage is not easy, and the annular flat plate is convenient to detach and recover in the cofferdam. The annular flat plate has a simple structure and is convenient to design and construct. The embedded part and the slope toe are fixedly integrated, and instability and damage of the annular flat plate are prevented.
Drawings
FIG. 1 is a schematic top view of the present application;
fig. 2 is a schematic sectional view a-a of fig. 1 of the present application.
Description of specific element symbols: 1. an annular flat plate; 2. a toe; 3. a riverbed.
Detailed Description
In order to more clearly describe the present invention, the present invention will be further described with reference to the accompanying drawings.
Referring to fig. 1 and 2, the invention discloses an annular flat plate structure for cofferdam toe protection, a cofferdam slope comprises a toe 2, the toe 2 is arranged below a horizontal plane, an annular flat plate 1 for buffering is horizontally arranged at an arc-shaped turning foot of the toe 2, the bottom of the annular flat plate 1 is arranged closely to the upper surface of a riverbed 3, an embedded part is arranged on the inner side of the annular flat plate 1 and embedded into the toe 2, the embedded part and the toe 2 are of a fixed integrated structure, a water flow buffering part is arranged on the outer side of the annular flat plate 1, the outer edge of the water flow buffering part is the same as the outer edge of the toe 2 in structure and is of an arc-shaped bent structure; the construction is simple, and is with low costs, and cofferdam corner toe 2 especially vertical cofferdam toe 2 scour protection effect is obvious, and protection cofferdam toe 2 is eluriated and is caused the cofferdam trouble. Because of the annular flat plate 1 of cofferdam toe 2 department can adjust the water flow state, smooth-going rivers make the adjustment of partial rivers direction, avoid directly undercutting to erode 2 department riverbed 3 surfaces of cofferdam toe, alleviate the washing out to 2 department riverbed 3 surfaces of cofferdam toe. Compared with the construction of the guide wall at the position of the cofferdam toe 2, the annular flat plate 1 is used for reducing the engineering quantity. The solid materials are cast and filled at the cofferdam toe 2, so that the river channel can be blocked, fishing at the later stage is not easy, and the annular flat plate 1 is convenient to detach and recover in the cofferdam. The annular flat plate 1 is simple in structure and convenient to design and construct. The embedded part and the slope toe 2 are fixedly integrated, and instability and damage of the annular flat plate 1 are prevented.
Example 2: referring to fig. 1 and 2, the annular flat plate 1 of the present embodiment is made of a steel plate and has a thickness of 0.01 to 0.06 m. And a steel plate with better cold bending performance is adopted to resist the impact force generated by water flow. The water flow buffer part of the annular flat plate 1 of the embodiment is arranged below the horizontal plane, and the width of the water flow buffer part below the horizontal plane is 2-3 m. The insert part of this embodiment is provided with anchoring means for fixing the insert part and the toe 2. So as to reduce the steel plate material in the cofferdam. The width of the embedded part of the embodiment is designed according to the stress analysis condition of the water flow buffer part. The water flow buffering part of the embodiment comprises an arc-shaped buffering part and extension buffering parts arranged on two sides of the arc-shaped buffering part, and the ratio of the length of the extension buffering part on one side to the arc length of the arc-shaped buffering part is 0.5-1: 1. In the present embodiment, the height of the upper surface of the water flow buffering portion gradually increases in a direction approaching the toe 2.
Example 3: referring to fig. 1 and 2, the present embodiment provides a method for testing a water tankAnnular flat plate 1 structure of cofferdam toe 2 protection, annular flat plate 1 thickness d is 0.01m, annular flat plate 1 width b outside the cofferdam10.10m, arc length of arc buffer part10.58m, extended cushioning portion length l20.35 m. The test result shows that after Q is 60L/s flow erodes stably, when using the dull and stereotyped 1 structure of annular, the water flow direction can be adjusted to the dull and stereotyped 1 of annular, and near the cofferdam toe 2 erodes the pit scope and squints in the middle of the river course, and cofferdam toe 2 can be protected.
The above disclosure is only for a few specific embodiments of the present invention, but the present invention is not limited thereto, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present invention.