Drainage structure of prefabricated top arch section of dam drainage gallery

Abstract

The invention discloses a prefabricated top arch section drainage structure of a dam drainage gallery, relates to the field of water conservancy projects, and solves the problems that an existing prefabricated top arch section is large in mass and inconvenient to prepare, transport and construct, and drainage holes are prone to failure. Comprising an arc-shaped plate forming the top of the drainage gallery and supporting plates connected with the four edges of the arc-shaped plate and arranged in the vertical direction, the top face of the arc-shaped plate and the four supporting plates define a filtering cavity with the top open, and the total mass of the prefabricated top arch section can be reduced easily; the filtering cavity is filled with water-permeable filler, the top of the water-permeable filler is covered with reverse filtering geotechnical cloth, the arc-shaped plate is provided with drainage holes communicated with the filtering cavity, the water-permeable filler can transmit loads on the upper portion to the arc-shaped plate in a dispersed mode, and concrete is directly cast in place above the reverse filtering geotechnical cloth. Seepage water of cast-in-place concrete can directly permeate into the filtering cavity through the reverse filtering geotechnical cloth and then is discharged from the drainage holes of the arc-shaped plate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydraulic engineering, in particular to a spillway or other structure for a dam, and more particularly to a prefabricated top arch segment of a drainage gallery. BACKGROUND

[0002] Gravity dams and arch dams are important water-retaining structures in hydropower projects. In order to lower the dam body saturation line position and reduce seepage pressure, a plurality of vertical drainage holes are usually provided through the gallery of each layer in the dam on the upstream side of the dam, up to the vicinity of the dam top or the top of the spillway, and a drainage hole curtain is formed.

[0003] Each drainage hole is generally formed by drilling between the upper and lower galleries or by pre-burying a drainage blind pipe. The seepage water in the dam body concrete can be guided and drained to the upstream corner of the top arch of the dam gallery through the drainage hole, and then guided and drained to the drainage ditch of the dam gallery through the drainage pipe. When the vertical drainage hole is formed by drilling, there may be a situation of misalignment of the drilled hole and the drainage pipe on the upstream side of the dam gallery, or a situation of disorder of the exposed position of the drainage hole, which affects the dam drainage effect. When the drainage hole is formed by pre-burying a drainage blind pipe, the drainage blind pipe needs to be connected to the drainage pipe of the dam gallery at the corner position of the dam gallery through a specific connection structure, which is complicated to construct. At the same time, the drainage blind pipe will affect the passage of construction machinery during the dam body pouring process, affect the passage and paving of the rolling equipment, and cause the drainage blind pipe part to become a weak part of rolling.

[0004] Patent CN 115387283 A discloses a prefabricated drainage cavity top arch structure of a drainage gallery, which includes a plurality of top arch structures arranged at the top of the drainage gallery. The top arch structures are arranged in sequence along the length direction of the drainage gallery and are connected to each other. The top arch structure is provided with a drainage cavity and a reserved drainage hole communicating with the drainage cavity. The drainage cavities of adjacent top arch structures are communicated. When drilling the drainage hole, the top of the top arch structure is drilled through, so that the drilled hole is connected to the drainage cavity. The seepage water in the drainage hole can enter the reserved drainage hole through the drainage cavity, and finally be drained into the drainage ditch of the drainage gallery.

[0005] The prefabricated drainage cavity top arch structure disclosed in the above patent can communicate the drainage hole with the drainage ditch of the drainage corridor without complex control means for accurate positioning, but still has the following disadvantages: first, the top of the drainage cavity is an upper bearing plate, the upper bearing plate is a reinforced concrete structure, which increases the overall mass of the top arch structure; second, the drainage cavity is a hollow structure, the inside of the drainage cavity is provided with a middle support structure, the middle support structure is an integral structure with the upper bearing plate and the corridor top arc-shaped plate, in order to ensure the strength of the top arch structure, the upper bearing plate and the corridor top arc-shaped plate are provided with much reinforcement and large thickness, for example, the thickness of the upper bearing plate is required to be greater than or equal to 25 cm, which leads to high overall cost and large mass of the arch structure, increases the construction difficulty of transportation and hoisting, and the drilling of the drainage hole needs to penetrate the upper bearing plate, which is relatively complicated; third, the drainage hole drilled in the upper part of the drainage cavity is directly connected with the drainage cavity, the drainage hole is easily blocked by mud and the like, once the drainage hole is blocked, the drainage hole cannot be connected with the drainage cavity, and the drainage hole loses the drainage function. SUMMARY

[0006] The application provides a prefabricated top arch segment drainage structure of a dam drainage corridor, which solves the problems of large mass of the existing prefabricated top arch segment, inconvenience in preparation, transportation and construction, and easy failure of the drainage hole.

[0007] The technical scheme adopted by the application is as follows: a prefabricated top arch segment drainage structure of a dam drainage corridor, which comprises an arc-shaped plate forming the top of the drainage corridor and four support plates connected with the four edges of the arc-shaped plate and arranged in the vertical direction, the top edges of the four support plates are located on the same horizontal plane, and the horizontal plane is higher than the highest position of the arc-shaped plate, the arc-shaped plate and the four support plates are both reinforced concrete structures and form an integral whole, the top surface of the arc-shaped plate and the four support plates enclose a top-open filter cavity, the arc-shaped plate is provided with at least one drainage hole communicating with the filter cavity, the filter cavity is filled with water-permeable filler, the top of the water-permeable filler is covered with a filter cloth, and the four edges of the filter cloth are fixed to the top of the four support plates respectively.

[0008] In order to ensure the strength of the arc-shaped plate and the four support plates, specifically, the minimum thickness of the arc-shaped plate is greater than or equal to 25 cm, the thickness of the support plate gradually decreases from the bottom to the top, and the minimum thickness of the support plate is greater than or equal to 25 cm, and the thickness of the bottom of the support plate is greater than or equal to 40 cm.

[0009] The water-permeable filler plays a role in transmitting load and permeating water, and specifically, the water-permeable filler is graded gravel.

[0010] The upper part of the prefabricated top arch segment is formed by cast-in-place concrete to form the dam, and a vertical drainage hole is drilled into the water-permeable filler to drain the seepage water of the cast-in-place concrete. In order to reduce the risk of drilling through the arc-shaped plate, the water-permeable filler needs to have a certain thickness. Generally, the minimum thickness of the water-permeable filler along the vertical direction is ≥ 25 cm.

[0011] In order to facilitate hoisting of the prefabricated top arch segment, further, the top of each of the four support plates is pre-buried with a lifting ring.

[0012] In order to facilitate fixation of the filter geotextile, further, the four edges of the filter geotextile are fixed to the top of the four support plates by rivets.

[0013] In order to facilitate butt joint of the prefabricated top arch segment, further, the side of the support plate on the downstream side of the dam, which faces away from the filter cavity, is provided with a positioning groove.

[0014] In order to facilitate drainage of the filter cavity, further, the bottom surface of the filter cavity is a slope, and the lowest part of the slope is provided with a drainage hole.

[0015] In order to ensure the drainage effect of the drainage hole on the filter cavity, further, the slope ratio of the bottom surface of the filter cavity is ≥ 5%.

[0016] Specifically, the arc-shaped plate is provided with one drainage hole, which is arranged at the midpoint position of the side of the arc-shaped plate corresponding to the upstream side of the dam; or the arc-shaped plate is provided with two drainage holes, one of which is arranged at the midpoint position of the side of the arc-shaped plate corresponding to the upstream side of the dam, and the other of which is arranged at the midpoint position of the side of the arc-shaped plate corresponding to the downstream side of the dam.

[0017] The beneficial effects of the present application are: the top of the filter cavity is open, which facilitates prefabrication of the arc-shaped plate and the four support plates, the arc-shaped plate and the four support plates form an integral whole, which ensures the overall strength of the prefabricated top arch segment and is conducive to reducing the total mass of the prefabricated top arch segment, thereby facilitating prefabrication, hoisting, transportation and installation construction. The filter cavity is filled with water-permeable filler, the top of the water-permeable filler is covered with filter geotextile, the top of the filter geotextile can be directly cast with concrete, the water-permeable filler can transmit the upper load to the arc-shaped plate in a dispersed manner, and the structure of the prefabricated top arch segment is optimized. The filter geotextile on the top of the water-permeable filler is directly cast with concrete, the seepage water of the cast-in-place concrete can directly penetrate into the filter cavity through the filter geotextile, and then be drained from the drainage hole of the arc-shaped plate, so the seepage water of the cast-in-place concrete can be drained without drilling a vertical drainage hole, and even if the vertical drainage hole drilled in the cast-in-place concrete is blocked, it will hardly affect the drainage of the seepage water of the cast-in-place concrete. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a planar structure schematic diagram of an embodiment of the present application.

[0019] Figure 2 yes Figure 1 The illustrated embodiment is a cross-sectional view along the AA direction.

[0020] Figure 3 yes Figure 1 The illustrated embodiment is a cross-sectional view along the BB direction.

[0021] Figure 4 yes Figure 1 The illustrated embodiment is a cross-sectional view along the CC direction.

[0022] Attached reference numerals: 1. Drainage gallery; 2. Curved plate; 3. Support plate; 4. Drainage hole; 5. Permeable filler; 6. Reverse filter geotextile; 7. Rivet; 8. Positioning groove. Detailed Implementation

[0023] The invention will now be further described with reference to the accompanying drawings.

[0024] like Figures 1 to 4 As shown, this invention discloses a precast arched drainage structure for a dam drainage gallery, comprising an arc-shaped plate 2 forming the top of the drainage gallery 1, and support plates 3 connected to the four sides of the arc-shaped plate 2 and arranged vertically. The arc-shaped plate 2 forms the top of the drainage gallery 1, and its four sides include two opposing arc-shaped edges and two opposing straight edges. The two arc-shaped edges are arranged along the extension direction of the drainage gallery 1, and the two straight edges are arranged along the upstream and downstream direction of the dam. The planes corresponding to the two straight edges are horizontal. The top edges of the four support plates 3 are located on the same horizontal plane, and this horizontal plane is higher than the highest point of the arc-shaped plate 2. Both the arc-shaped plate 2 and the four support plates 3 are reinforced concrete structures and are an integral whole, that is, the arc-shaped plate 2 and the four support plates 3 are cast as a whole and are precast structures. Generally, the concrete strength grade of the precast arch segment is consistent with the concrete strength grade of the dam concrete zone. The reinforcement of the precast arch segment is calculated according to the gallery size. For precast arch segments with a span ≤3.5m, the diameter of the structural steel bars is generally not less than 16mm, and the spacing between the steel bars is 15cm to 20cm.

[0025] To ensure the strength of the arc-shaped plate 2 and the four supporting plates 3, the minimum thickness of the arc-shaped plate 2 is generally ≥25cm, and the minimum thickness of the supporting plates 3 is ≥25cm. Based on the stress on the two supporting plates 3 located upstream and downstream of the dam, the thickness of these two supporting plates 3 gradually decreases from bottom to top. The outer surfaces of these two supporting plates 3 are sloped, and the thickness at the bottom of the supporting plates 3 is ≥40cm. The thickness of the two supporting plates 3 arranged along the extension direction of the drainage gallery 1 is consistent at different positions to facilitate the combination of the present invention.

[0026] The top surface of the arc-shaped plate 2 and the four support plates 3 form a top-open filter cavity, and the filter cavity is filled with water-permeable filler 5. The upper part of the four support plates 3 located in the filter cavity is actually a baffle. The water-permeable filler 5 plays a role of transmitting load and permeating water, for example, the water-permeable filler 5 is graded gravel, generally, the maximum particle size of the gravel is not more than 4 cm, and the graded gravel is uniformly laid in the filter cavity. The arc-shaped plate 2 is provided with a drainage hole 4 communicating with the filter cavity, and the drainage hole 4 is used to guide and drain the seepage water in the filter cavity into the drainage gallery 1, for example, into the drainage ditch at the bottom of the drainage gallery 1. There is at least one drainage hole 4, that is, one or more drainage holes 4 of one prefabricated top arch segment. The drainage hole 4 is reserved when the arc-shaped plate 2 is poured, and a pipeline is generally formed when the arc-shaped plate 2 is poured. For example, the drainage hole 4 is formed by a PVC pipe with an inner diameter of 250 mm, and the PVC pipe is reserved in the drainage gallery 1 for a certain length to facilitate the connection of the water collecting funnel.

[0027] The bottom surface of the filter cavity can be of any shape, that is, the top surface of the arc-shaped plate 2 can be of any shape. In order to facilitate the drainage of the filter cavity and reduce the amount of water stored in the filter cavity, the bottom surface of the filter cavity is a slope, and the lowest part of the slope is provided with a drainage hole 4. For example, see Figures 2 to 4 , the arc-shaped plate 2 is provided with one drainage hole 4, and the drainage hole 4 is arranged at the midpoint position of the side corresponding to the upstream side of the dam of the arc-shaped plate 2. In addition, in order to reduce the mass of the present application, the arc-shaped plate 2 can also be provided with two drainage holes 4, one drainage hole 4 is arranged at the midpoint position of the side corresponding to the upstream side of the dam of the arc-shaped plate 2, and the other drainage hole 4 is arranged at the midpoint position of the side corresponding to the downstream side of the dam of the arc-shaped plate 2. In order to ensure the drainage effect of the drainage hole 4 on the filter cavity, the slope ratio of the bottom surface of the filter cavity is generally ≥1%, for example, the slope ratio of the bottom surface of the filter cavity is ≥5%.

[0028] The top of the water-permeable filler 5 is covered with a filter cloth 6, and the four edges of the filter cloth 6 are fixed to the top of the four support plates 3, respectively. The four edges of the filter cloth 6 generally wrap the top of the four support plates 3 and are then fixed to the support plates 3. In order to facilitate construction and ensure the stability of the filter cloth 6, the four edges of the filter cloth 6 are fixed to the top of the four support plates 3 by rivets 7. For example, the rivets 7 can be arranged at an interval of 20 cm.

[0029] After the side wall of the drainage gallery 1 of the dam is poured, the present application is installed on the top of the side wall, and the arc-shaped plate 2 directly forms the arch-shaped part of the drainage gallery 1. The length of the prefabricated top arch segment can be adjusted according to the length of the dam segment, the lifting capacity, and the actual engineering needs, wherein the length of the prefabricated top arch segment is the length of the prefabricated top arch segment in the extension direction of the drainage gallery 1. In order to facilitate the lifting of the prefabricated top arch segment, the top of the support plate 3 is pre-buried with a lifting ring. The top of the four support plates 3 is pre-buried with a lifting ring, which can ensure the balance of lifting. The lifting ring generally uses first-class steel bars, which must meet the load requirements in the lifting process and meet the relevant specification requirements. The width of the prefabricated top arch segment is greater than or equal to the width of the drainage gallery 1, and the water-permeable filler 5 exceeds the side wall of the drainage gallery 1 in the downstream direction of the dam.

[0030] After the present application is continuously installed on the top of the side wall of the drainage gallery 1 in the extension direction of the drainage gallery 1, the prefabricated top arch segment can be directly poured with concrete to form the dam, that is, the concrete is directly poured above the filter geotextile 6 to form the dam. In order to facilitate the butt joint of the prefabricated top arch segment, the side of the support plate 3 located on the downstream side of the dam and facing away from the filter cavity is provided with a positioning groove 8. In order to better combine the present application with the cast-in-place concrete, the positioning grooves of each prefabricated top arch segment are completely aligned, and after the entire prefabricated top arch segment is installed, holes can be drilled at the lower parts of the two support plates 3 located in the upstream and downstream directions of the dam, for example, holes are drilled at intervals of 0.50 m, the drilling depth is not less than 0.50 m, and a limiting anchor is installed in the hole, for example, the limiting anchor has a diameter of not less than 25 mm, and the exposed length of the limiting anchor is not less than 0.30 m.

[0031] The present application has two functions, one is that the present application serves as a pouring formwork for the top arch concrete of the drainage gallery 1, and after the construction is completed, it becomes part of the permanent structure of the top of the drainage gallery 1; the other is that the drainage hole 4 of the present application becomes a drainage outlet in the gallery, and the seepage water of the concrete on the upper part of the drainage gallery 1 enters the filter cavity and is led out to the drainage gallery 1 through the drainage hole 4.

[0032] The water seepage of the cast-in-place concrete can directly penetrate into the filter cavity through the filter cloth 6, and then be discharged from the drainage hole 4 of the arc-shaped plate 2. In order to improve the water seepage discharge efficiency of the cast-in-place concrete, a vertical drainage hole is generally drilled in the cast-in-place concrete, and the lower end of the vertical drainage hole enters the filter cavity. In order to reduce the risk of the drilling hole penetrating through the arc-shaped plate 2, the water-permeable filler 5 needs to have a certain thickness. Generally, the minimum thickness of the water-permeable filler 5 along the vertical direction is greater than or equal to 25 cm, that is, the distance between the highest position of the arc-shaped plate 2 and the plane corresponding to the filter cloth 6 is greater than or equal to 25 cm. The filter cavity has a large area in the horizontal plane, and even if there is a deviation when drilling the vertical drainage hole, as long as the deviation is not too large, the drilling hole can enter the filter cavity, thereby avoiding the deviation problem of the drilling of the vertical drainage hole. Moreover, the drilling speed of the drill bit in the concrete and in the water-permeable filler 5 is obviously different, so it is convenient to find out in time. The filter cavity is filled with the water-permeable filler 5, which improves the stress of the structure of the present application, so that the present application can provide stable support for the mechanized rapid construction of the warehouse surface.

Claims

1. A precast arched drainage structure for a dam drainage gallery, comprising an arc-shaped plate (2) forming the top of the drainage gallery (1), and support plates (3) connected to the four sides of the arc-shaped plate (2) and arranged vertically, wherein the top edges of the four support plates (3) are located on the same horizontal plane, and this horizontal plane is higher than the highest position of the arc-shaped plate (2), and the arc-shaped plate (2) and the four support plates (3) are all reinforced concrete structures and are an integral whole, characterized in that: The top surface of the arc plate (2) and the four support plates (3) form a filter chamber with an open top. The arc plate (2) is provided with a drainage hole (4) that communicates with the filter chamber. There is at least one drainage hole (4). The filter chamber is filled with permeable filler (5). The top of the permeable filler (5) is covered with a reverse filter geotextile (6). The four sides of the reverse filter geotextile (6) are fixed to the top of the four support plates (3).

2. The precast arch segment drainage structure for a dam drainage gallery as described in claim 1, characterized in that: The minimum thickness of the arc plate (2) is ≥25cm, the thickness of the support plate (3) gradually decreases from bottom to top, the minimum thickness of the support plate (3) is ≥25cm, and the thickness of the bottom of the support plate (3) is ≥40cm.

3. The precast arch segment drainage structure for a dam drainage gallery as described in claim 1, characterized in that: The permeable filler (5) is graded crushed stone.

4. The precast arch segment drainage structure for a dam drainage gallery as described in claim 1, characterized in that: The minimum thickness of the permeable filler (5) in the vertical direction is ≥25cm.

5. The precast arch segment drainage structure for a dam drainage gallery as described in claim 1, characterized in that: The top of each of the four support plates (3) is pre-embedded with a lifting ring.

6. The precast arch segment drainage structure for a dam drainage gallery as described in claim 1, characterized in that: The four sides of the reverse filter geotextile (6) are fixed to the top of the four support plates (3) by rivets (7).

7. The precast arch segment drainage structure for a dam drainage gallery as described in claim 1, characterized in that: The support plate (3) located on the downstream side of the dam has a positioning groove (8) on the side facing away from the filter chamber.

8. A precast arch segment drainage structure for a dam drainage gallery as described in any one of claims 1 to 7, characterized in that: The bottom surface of the filter chamber is inclined, and a drain hole (4) is provided at the lowest point of the inclined surface.

9. A precast arch segment drainage structure for a dam drainage gallery as described in claim 8, characterized in that: The slope of the bottom surface of the filter chamber is ≥5%.

10. A precast arch segment drainage structure for a dam drainage gallery as described in claim 8, characterized in that: The arc plate (2) is provided with a drainage hole (4), which is located at the midpoint of the side of the arc plate (2) corresponding to the upstream side of the dam; or, the arc plate (2) is provided with two drainage holes (4), one drainage hole (4) is located at the midpoint of the side of the arc plate (2) corresponding to the upstream side of the dam, and the other drainage hole (4) is located at the midpoint of the side of the arc plate (2) corresponding to the downstream side of the dam.

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