Dam foundation drainage device for heightening gravity dam

Abstract

The utility model discloses a dam foundation drainage device for a heightened gravity dam, which comprises a drainage device positioned in a new dam, the drainage device comprises horizontal main drainage pipes located at the downstream dam toe of the old dam, a plurality of first diversion branch pipes which horizontally extend into the old dam by 5-10 m are evenly distributed on the side, facing the old dam, of each row of horizontal main drainage pipes, and second diversion branch pipes with downward outlets are connected to the side, away from the old dam, of each row of horizontal main drainage pipes. The outlet of the second diversion branch pipe extends into the bottom and is used for collecting seepage water; the submersible pump is positioned in the water collecting well; and the maintenance platform is connected with the submersible pump through a vertical drainage pipe and is positioned on the downstream surface of the new dam. The structure is convenient to arrange and maintain, the construction efficiency can be improved, the whole device is located in the dam body, direct washing of water flow is effectively avoided, the durability of the device is improved, and the requirements for dam foundation drainage and uplift pressure reduction are met.

Description

Technical Field

[0001] The utility model relates to the technical field of gravity dam engineering, in particular to a dam foundation drainage device used for heightening a gravity dam. Background Art

[0002] With the rapid growth of social economy, the demand for water resources is also increasing. To meet this demand, it is urgent to develop new water resources projects or expand the capacity of existing projects. Compared with the construction of new dams, the dam heightening project is smaller and the project cost is lower. Therefore, dam heightening has become the main means for many countries to expand the capacity and increase the efficiency of existing reservoirs, and is regarded as an economical and practical way to redevelop water conservancy projects.

[0003] For the heightened gravity dam, there are differences in the bedrock between the new dam and the old dam. After the dam is heightened and thickened, the increase in the reservoir water level will increase the load on the bedrock, especially the uplift pressure on the dam bottom, which will affect the anti-sliding stability of the dam. Therefore, it is necessary to comprehensively consider anti-seepage and drainage to solve this problem. At present, the measure to reduce uplift pressure is usually to set up a drainage corridor in the dam and drill drainage holes in the corridor toward the dam foundation. Although this method is more effective in achieving dam foundation drainage, the setting of the corridor itself will weaken the dam structure to a certain extent, and there are certain safety hazards.

[0004] Therefore, it is urgent to solve the above problems. Utility Model Content

[0005] Purpose of the utility model: The purpose of the utility model is to provide a dam foundation drainage device for heightening a gravity dam, which has a simple structural arrangement, is convenient to construct and is located inside the gravity dam body.

[0006] Technical solution: To achieve the above purpose, the utility model discloses a dam foundation drainage device for raising the gravity dam, including a drainage device located in the new dam, the drainage device including a horizontal main drainage pipe located at the toe of the dam downstream of the old dam, a plurality of first diversion branch pipes extending into the old dam for 5 to 10 m evenly distributed on the side of each row of horizontal main drainage pipes facing the old dam, a second diversion branch pipe connected to the water outlet and having a water outlet on the side of each row of horizontal main drainage pipes away from the old dam, a water collection well with an outlet of the second diversion branch pipe extending into the bottom and used for collecting seepage water, a submersible pump located in the water collection well, and an inspection platform connected to the submersible pump through a vertical drainage pipe and located on the downstream side of the new dam.

[0007] Among them, a prefabricated steel frame for reinforcement is provided on the outside of the horizontal main drainage pipe, which includes vertical steel bars located on both sides above the horizontal main drainage pipe, longitudinal bars located on both sides below the horizontal main drainage pipe, and a number of stirrups evenly distributed at a certain distance along the longitudinal direction of the horizontal main drainage pipe.

[0008] Preferably, a concrete protective layer is reserved between the prefabricated steel frame and the horizontal main drainage pipe to prevent the horizontal main drainage pipe from being crushed, and the shortest distance of the concrete protective layer is 3 cm.

[0009] Furthermore, the horizontal main drainage pipes are arranged parallel to the dam axis along the downstream toe of the old dam, with one row of horizontal main drainage pipes arranged in each dam section.

[0010] Furthermore, the horizontal main drainage pipe in each dam section is provided with a plurality of diversion holes for connecting the first diversion branch pipe, and the hole spacing between adjacent diversion holes is 3 to 5 m.

[0011] Furthermore, the horizontal main drainage pipe is a hard PVC pipe, and the diameter of the horizontal main drainage pipe is 20 to 30 cm.

[0012] Preferably, the outer wall of the horizontal main drainage pipe is covered with a layer of geomembrane for waterproofing.

[0013] Furthermore, a steel wire rope is connected between the submersible pump and the maintenance platform for easy maintenance.

[0014] Preferably, the diameter of the vertical drain pipe is 20 to 30 cm.

[0015] Furthermore, the maintenance platform is 5 to 10 m higher than the downstream water level.

[0016] Beneficial effects: Compared with the prior art, the utility model has the following advantages: first, before the new concrete dam is poured, the utility model arranges the horizontal main drainage pipe at the toe of the old dam downstream parallel to the dam axis, drills a water diversion hole in the old dam to pre-bury the first diversion branch pipe, and combines the water collection well, submersible pump and vertical drainage pipe to form a set of systematic and sustainable drainage devices; compared with setting up a drainage corridor downstream, this set of devices can minimize the impact on the dam structure and maintain the safety of dam operation; secondly, the utility model has convenient structural layout, the submersible pump used is simple, and it is connected to the maintenance platform with a wire rope for easy maintenance. It can improve construction efficiency and reduce engineering costs; thirdly, the utility model proposes to use a prefabricated steel frame to reinforce the horizontal main drainage pipe, and use the reinforced concrete structure to bear the force together, which can protect the horizontal main drainage pipe from being damaged; finally, the entire device is located in the dam body, which effectively avoids direct scouring of water flow, improves the durability of the device, and meets the requirements of reducing uplift pressure for dam foundation drainage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional schematic diagram of the heightened gravity dam of the utility model;

[0018] Figure 2 It is a two-dimensional schematic diagram of the arrangement of the drainage device in the utility model;

[0019] Figure 3 It is a three-dimensional schematic diagram of the arrangement of the drainage device in the utility model;

[0020] Figure 4 It is a side view of the prefabricated steel bar skeleton in the utility model;

[0021] Figure 5 This is a front view of the prefabricated steel bar skeleton in the utility model;

[0022] Marked in the figure are: new dam 1, old dam 2, horizontal main drainage pipe 3, first diversion branch pipe 4, second diversion branch pipe 5, collection well 6, submersible pump 7, vertical drainage pipe 8, maintenance platform 9, erection steel bars 10, longitudinal bars 11, stirrups 12, concrete protective layer 13, geomembrane 14, steel wire rope 15, drainage device 16. DETAILED DESCRIPTION

[0023] The technical solution of the utility model is further described below in conjunction with the accompanying drawings.

[0024] like Figure 1 , Figure 2 and Figure 3 As shown, the utility model is a dam foundation drainage device for raising the gravity dam. A drainage device 16 is provided in the area above the dam foundation of the old dam 2. The drainage device 16 includes a horizontal main drainage pipe 3. The horizontal main drainage pipe 3 is pre-buried at the dam toe downstream of the old dam before the new dam is poured downstream. The horizontal main drainage pipe 3 is arranged parallel to the dam axis, and one row is arranged in each dam section. The diameter of the horizontal main drainage pipe 3 is 20 to 30 cm. A diversion hole is drilled on the dam foundation surface downstream of the old dam 2 and a plurality of five first diversion branch pipes 4 are pre-buried and connected to the horizontal main drainage pipe 3. The first diversion branch pipe 4 extends 5 to 10 m into the old dam through the diversion hole. The horizontal main drainage pipe 3 in each dam section is provided with five diversion holes. The hole spacing of adjacent diversion holes is 3 to 5 m. The diameter of the diversion hole is 5 to 10 cm, and its diameter matches the outer diameter of the first diversion branch pipe 4. Two water outlets are arranged at the bottom of the horizontal main drainage pipe 3 near the downstream, and the water outlets are connected to the second diversion branch pipe 5, through which the seepage water is discharged into the water collection well 6. The horizontal main drainage pipe 3 adopts a hard PVC pipe. At the same time, a layer of geomembrane 14 is wrapped around the horizontal main drainage pipe 3. The geomembrane 14 is a polymer chemical flexible material. It uses its impermeability to block the leakage channel of the dam body, and its greater tensile strength and elongation can withstand water pressure and adapt to the deformation of the dam body to achieve a waterproof effect. The horizontal main drainage pipe 3 is reinforced with a prefabricated steel frame, which can bear force together with the reinforced concrete structure composed of the newly poured concrete to protect the horizontal main drainage pipe from being damaged. Figure 4 and Figure 5As shown, the prefabricated steel skeleton includes vertical steel bars 10, longitudinal bars 11 and stirrups 12. The diameters of the vertical steel bars 10 and longitudinal bars 11 are 12 mm, the diameter of the stirrups 12 is 6 mm, and the stirrups 12 are spaced 15 to 20 cm apart. A concrete protective layer 13 with a minimum distance of about 3 cm is reserved between the prefabricated steel skeleton and the horizontal main drainage pipe 3 to prevent the horizontal main drainage pipe 3 from being crushed. When pouring the dam body concrete, the horizontal main drainage pipe 3 should be blocked with a grout stopper to prevent cement slurry from leaking into the pipe, blocking the drainage pipe and affecting the drainage effect.

[0025] The projection of the water collection well 6 in its cross section is square, and the cross-sectional size is 50cm×50cm. When the water collection well 6 collects a certain amount of seepage water, the seepage water in the water collection well 6 is pumped out to the maintenance platform 9 on the downstream side of the new dam 1 by the submersible pump 7, and the seepage water of the dam foundation is discharged in time. The diameter of the vertical drainage pipe 8 connected with the submersible pump 7 and the maintenance platform 9 is about 20-30cm. The submersible pump 7 and the maintenance platform 9 are connected by a wire rope 15 for easy maintenance. The maintenance platform 9 is 5-10m higher than the downstream water level. When the downstream water level is high, there is a certain pressure head at the dam foundation. At this time, the seepage water of the dam foundation can enter the horizontal main drainage pipe 3 through the first diversion branch pipe 4, and then the seepage water is discharged into the water collection well 6 by the second diversion branch pipe 5 connected to the outlet of the horizontal main drainage pipe 3; when the water collection well 6 collects a certain amount of seepage water, the seepage water in the water collection well 6 is pumped out by the submersible pump 7 and discharged to the maintenance platform 9 on the downstream side of the new dam through the vertical drainage pipe 8.

[0026] Before the concrete new dam 1 is poured, the utility model pre-buries a horizontal main drainage pipe 3 at the downstream dam toe of the old dam 2 parallel to the dam axis direction, and drills a water diversion hole in the old dam 2 to pre-buried a first diversion branch pipe 4. When there is a lot of water seepage in the dam foundation, the seepage water can be discharged into the water collection well 6 through the horizontal main drainage pipe 3, and then the seepage water in the water collection well 6 is pumped out by a submersible pump 7, and discharged to the maintenance platform 9 on the downstream surface of the new dam through a vertical drainage pipe 8, thereby achieving the effect of reducing the uplift pressure of the dam foundation, improving the anti-slip stability of the heightened gravity dam, ensuring the safety of the dam, and having practical significance and good application prospects.

[0027] In the above-mentioned implementation, considering the construction characteristics of the current heightened gravity dam foundation, in order to simplify the construction process, improve construction efficiency, reduce the project cost, and ensure the drainage function of the drainage device and the effectiveness of its service life, before the concrete new dam 1 is poured, the utility model arranges the horizontal main drainage pipe 3 along the downstream dam toe of the old dam 2 parallel to the dam axis, drills a water diversion hole in the old dam 2 to pre-bury the first diversion branch pipe 4, and combines the water collection well 6, the submersible pump 7 and the vertical drainage pipe 8 to form a set of systematic and sustainable drainage devices. Compared with setting up a drainage corridor downstream, the utility model, a dam foundation drainage device for heightened gravity dams, can minimize the impact on the dam structure, maintain the safety of dam operation, and the entire drainage device is located in the dam body, effectively avoiding direct scouring by water flow, improving the durability of the device, and meeting the requirements of reducing uplift pressure in dam foundation drainage.

Claims

1. A dam foundation drainage device for raising a gravity dam, characterized in that: The invention comprises a drainage device (16) located in a new dam (1), the drainage device (16) comprising a horizontal main drainage pipe (3) located at the toe of the downstream of the old dam (2), a plurality of first diversion branch pipes (4) uniformly arranged on the side of each row of horizontal main drainage pipes facing the old dam and extending horizontally into the old dam by 5 to 10 m, a second diversion branch pipe (5) connected to the side of each row of horizontal main drainage pipes away from the old dam and having an outlet facing downward, a water collection well (6) whose outlet extends into the bottom and is used to collect seepage water, a submersible pump (7) located in the water collection well, and a maintenance platform (9) connected to the submersible pump (7) via a vertical drainage pipe (8) and located on the downstream side of the new dam.

2. A dam foundation drainage device for raising a gravity dam according to claim 1, characterized in that: A prefabricated steel frame for reinforcement is provided on the outside of the horizontal main drainage pipe (3), the prefabricated steel frame comprising vertical reinforcement bars (10) located on both sides above the horizontal main drainage pipe, longitudinal reinforcement bars (11) located on both sides below the horizontal main drainage pipe, and a plurality of stirrups (12) evenly distributed at a certain distance along the longitudinal direction of the horizontal main drainage pipe.

3. A dam foundation drainage device for raising a gravity dam according to claim 2, characterized in that: A layer of concrete protective layer (13) is reserved between the prefabricated steel frame and the horizontal main drainage pipe (3) to prevent the horizontal main drainage pipe from being crushed, and the shortest distance of the concrete protective layer (13) is 3 cm.

4. The dam foundation drainage device for raising a gravity dam according to claim 1, characterized in that: The horizontal main drainage pipes (3) are arranged along the toe of the downstream of the old dam and parallel to the dam axis, with one row of horizontal main drainage pipes (3) arranged in each dam section.

5. A dam foundation drainage device for raising a gravity dam according to claim 4, characterized in that: The horizontal main drainage pipe (3) in each dam section is provided with a plurality of diversion holes for connecting to the first diversion branch pipe, and the hole spacing between adjacent diversion holes is 3-5 m.

6. The dam foundation drainage device for raising a gravity dam according to claim 1, characterized in that: The horizontal main drainage pipe (3) is a hard PVC pipe, and the diameter of the horizontal main drainage pipe (3) is 20 to 30 cm.

7. The dam foundation drainage device for raising a gravity dam according to claim 1, characterized in that: The outer wall of the horizontal main drainage pipe (3) is coated with a layer of geomembrane (14) for waterproofing.

8. The dam foundation drainage device for raising a gravity dam according to claim 1, characterized in that: A steel wire rope (15) is connected between the submersible pump (7) and the maintenance platform (9) to facilitate maintenance.

9. The dam foundation drainage device for raising a gravity dam according to claim 1, characterized in that: The diameter of the vertical drainage pipe (8) is 20-30 cm.

10. The dam foundation drainage device for raising a gravity dam according to claim 1, characterized in that: The inspection platform (9) is 5 to 10 m higher than the downstream water level.

Images