Structural Type and Construction Method of Drainage Holes in the Permeable Bottom Slab of a Stilling Basin

Abstract

The present invention discloses a structural type and construction method of drainage holes for a permeable bottom slab of a stilling basin: 1. Excavate the designed excavation elevation on the building foundation and arrange sump pits; 2. Place the drainage perforated pipe into the sump pits; 3. Place the filter assembly into the drainage perforated pipe; 4. Connect the trapezoidal drainage pipe to the upper end of the drainage perforated pipe; 5. Pour the concrete for the stilling basin bottom slab and the anti-scour and wear-resistant concrete respectively; 6. Fill the trapezoidal drainage pipe with gravel; 7. Pour non-sand concrete into the trapezoidal drainage pipe to cover up to the elevation of the flow surface. The structural type of the drainage holes for the permeable bottom slab of the stilling basin provided by the present invention solves the problem of anti-floating stability of the stilling basin bottom slab, and is not likely to cause seepage damage to the foundation of the stilling basin bottom slab and risks such as uplift and cracking of the bottom slab, improving the engineering safety.

Description

Technical Field

[0001] The invention belongs to the technical field of water conservancy and hydropower engineering, relates to the structural type of drainage holes on the permeable bottom slab of a stilling basin, and also relates to a construction method for the structural type of drainage holes on the permeable bottom slab of the stilling basin. Background Art

[0002] In water conservancy and hydropower engineering, the bottom slab of a stilling basin is extremely prone to situations such as overturning, heaving and cracking under the action of seepage pressure, resulting in a relatively high failure rate of the downstream stilling basin. In order to enable the water below the bottom slab of the stilling basin to be discharged smoothly, reduce the seepage pressure of the stilling basin, and ensure the safety and normal operation of the stilling basin and the dam body, it is necessary to make the bottom slab of the stilling basin a permeable bottom slab or arrange an underground drainage system at the bottom of the slab.

[0003] However, arranging an underground drainage system under the bottom slab often has disadvantages such as complex construction, easy blockage, and inconvenient maintenance. The permeable bottom slab is relatively more widely used, that is, the open drainage scheme. Drainage holes are used to directly discharge the pressurized groundwater into the stilling basin without the need for pumping and pressure reduction, and the operation method is simple. Most of the open drainage schemes adopt drainage holes with equal diameters. However, during flood discharge, under the action of dynamic water and seepage pressure, the bottom slab of the stilling basin is prone to seepage failure, heaving and cracking of the bottom slab, etc. The drainage holes are extremely easy to be silted up by sediment, and the filter device in the drainage holes is easy to be washed away, accelerating the occurrence of seepage failure of the bottom slab.

[0004] Therefore, a structural type of drainage holes on the permeable bottom slab of a stilling basin is needed, which can solve the problem of anti-floating stability of the bottom slab of the stilling basin, ensure the safety of the project, and at the same time can effectively prevent scouring and blockage, and has the characteristics of simple construction technology, fast construction speed, convenient operation and maintenance, and economic applicability. Summary of the Invention

[0005] The purpose of the invention is to provide a structural type of drainage holes on the permeable bottom slab of a stilling basin, which is more convenient for maintenance and has simple construction. While solving the anti-floating stability problem of the bottom slab of the stilling basin, it is not easy to cause seepage failure of the foundation of the bottom slab of the stilling basin and risks such as heaving and cracking of the bottom slab, improving the safety of the project.

[0006] Another purpose of the invention is to provide a construction method for the structural type of drainage holes on the permeable bottom slab of the stilling basin.

[0007] The first technical solution adopted by the invention is a structural type of drainage holes on the permeable bottom slab of a stilling basin. "Trapezoidal" drainage holes are arranged on the bottom slab of the stilling basin. The structural type of the "trapezoidal" drainage holes is that the bottom is for drainage and filtration, the middle is filled with permeable gravel, and the top is a cast-in-place frustum-shaped permeable concrete cover.

[0008] The second technical solution adopted by the invention is a construction method for the structural type of drainage holes on the permeable bottom slab of a stilling basin. The specific method is as follows:

[0009] Step 1: Excavate the foundation of the building, dig out the designed excavation elevation, and arrange sump pits on the basis of the designed excavation elevation;

[0010] Step 2: Place the drain perforated pipe into the sump pit;

[0011] Step 3: Place the filter assembly into the drain perforated pipe and make it higher than the designed excavation elevation;

[0012] Step 4: Connect the trapezoidal drain pipe to the upper end of the drain perforated pipe;

[0013] Step 5: Use the trapezoidal drain pipe and the drain perforated pipe as templates to pour the concrete for the stilling basin floor slab and the erosion-resistant and wear-resistant concrete respectively;

[0014] Step 6: Fill the trapezoidal drain pipe with gravel;

[0015] Step 7: Pour non-sand concrete into the trapezoidal drain pipe to cover it up to the overflow surface elevation.

[0016] The features of the present invention further lie in:

[0017] In Step 2, the depth of the sump pit is 50 cm to 100 cm.

[0018] In Step 3, the filter assembly is specifically obtained by wrapping coarse sand with non-woven filter cloth and winding and fixing it with nylon rope. The height of the filter assembly is 20 cm to 30 cm higher than the designed excavation elevation.

[0019] In Step 4, the longitudinal section of the drain pipe is of a trapezoidal structure. The larger-diameter end of the drain pipe is fixedly connected to the upper end of the drain perforated pipe through the steel mesh of the stilling basin floor slab;

[0020] The upper and lower diameters of the drain perforated pipe are the same.

[0021] In Step 5, the lower layer pours the concrete for the stilling basin floor slab, and the upper layer pours the erosion-resistant and wear-resistant concrete.

[0022] In Step 6, the particle size of the gravel is 1 cm. The bottom of the laid gravel is 20 to 30 cm above the bottom surface of the stilling basin floor slab concrete, and the top of the laid gravel is 15 to 20 cm below the overflow surface.

[0023] In Step 7, the non-sand concrete cover is of a frustum structure with a larger bottom and a smaller top, and the thickness of the non-sand concrete cover is 15 to 20 cm.

[0024] The beneficial effects of the present invention are:

[0025] (1) For the structural type of the drainage holes of the permeable floor slab of the stilling basin in the present invention, the upper trapezoidal non-sand concrete cover adopts a frustum structure with a larger bottom and a smaller top, and is not easily washed out of the drainage holes under the action of high-speed water flow and pulsating pressure, thereby protecting the coarse sand and gravel at the lower part of the drain pipe and playing a role in preventing the erosion and damage of the drainage holes;

[0026] (2) The structural type of the drainage holes in the permeable bottom slab of the stilling basin of the present invention is that after wrapping coarse sand with non-woven filter cloth and fixing it with nylon rope winding, it penetrates into the sump 50 cm deep below, which can effectively prevent the blockage of the drainage holes while performing reverse filtration; after wrapping coarse sand with non-woven filter cloth and fixing it with nylon rope, it is then put into the plastic perforated pipe, and there is no need to seal the top of the pipe later, with simple processes and convenient construction;

[0027] (3) The structural type of the drainage holes in the permeable bottom slab of the stilling basin of the present invention is that the drainage perforated pipe is connected to the trapezoidal drainage pipe, arranged according to the layout of the drainage holes, and fixed by means of the steel bar mesh of the stilling basin bottom slab, which can also play the role of a formwork to prevent concrete from entering the drainage pipe during pouring, with simple construction, can be prefabricated in advance, and does not affect the construction period;

[0028] (4) The structural type of the drainage holes in the permeable bottom slab of the stilling basin of the present invention, by arranging trapezoidal combined drainage holes in the stilling basin bottom slab, with the combined method of "bottom drainage reverse filtration + middle permeable stones + top cast-in-place trapezoidal permeable concrete cover" inside, can not only effectively prevent blockage and scour, but also play the role of water permeability, reduce the seepage pressure of the bottom slab, prevent the damage of the stilling basin bottom slab, and ensure the safe operation of the project. Description of the Drawings

[0029] Figure 1 is a schematic diagram of the structural type of the drainage holes in the permeable bottom slab of the stilling basin of the present invention;

[0030] Figure 2 is the present invention Figure 1 Schematic diagram of the a-a cross-sectional structure in the structural type of the drainage holes in the permeable bottom slab of the stilling basin;

[0031] Figure 3 is the present invention Figure 1 Schematic diagram of the b-b cross-sectional structure in the structural type of the drainage holes in the permeable bottom slab of the stilling basin.

[0032] In the figure, 1. Building foundation, 2. Designed excavation elevation, 3. Sump, 4. Trapezoidal drainage pipe, 5. Drainage perforated pipe, 6. Non-woven filter cloth, 7. Coarse sand, 8. Nylon rope, 9. Stones, 10. Concrete inner wall, 11. Non-sand concrete cover, 12. Stilling basin bottom slab concrete, 13. Stilling basin top anti-scour and wear-resistant concrete, 14. Flow surface. Detailed Embodiments

[0033] The present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0034] The structural type of the drainage holes in the permeable bottom slab of the stilling basin, as Figure 1As shown in the figure, "trapezoidal" drainage holes are arranged on the stilling basin floor slab. The "trapezoidal" drainage hole structure type is a bottom drainage and filtration, with permeable gravel in the middle and a cast-in-place frustum-shaped permeable concrete cover at the top.

[0035] Drainage and filtration are arranged at the bottom to prevent fine particles in the pool foundation from being carried away and aggravating the seepage failure. Permeable gravel is arranged in the middle to increase the water permeability of drainage. By setting a "trapezoidal" permeable concrete cover with a larger bottom and a smaller top at the top, it can not only play the role of water permeability but also ensure that the top permeable concrete cover is not washed away under the action of moving water. The structure type of the drainage hole of the permeable floor slab of the stilling basin in the present invention is a structure type of the drainage hole of the permeable floor slab of the stilling basin that prevents blockage and scouring, effectively ensuring the project safety.

[0036] The construction method of the structure type of the drainage hole of the permeable floor slab of the stilling basin is as follows:

[0037] Step 1: Excavate the building foundation 1 to the designed excavation elevation 2, and arrange a sump 3 on the basis of the designed excavation elevation 2;

[0038] Step 2: Place the drainage perforated pipe 5 into the sump 3, where the depth of the sump 3 is 50 cm to 100 cm;

[0039] Step 3: As Figure 2 shown in the figure, place the filter assembly into the drainage perforated pipe 5 and be higher than the designed excavation elevation 2; the filter assembly is specifically obtained by wrapping coarse sand 7 with a non-woven filter cloth 6 and winding and fixing it with a nylon rope 8, and the height of the filter assembly above the designed excavation elevation 2 is 20 cm to 30 cm;

[0040] Step 4: Connect the trapezoidal drainage pipe 4 to the upper end of the drainage perforated pipe 5;

[0041] Among them, the longitudinal section of the trapezoidal drainage pipe 4 is a trapezoidal structure, that is, the upper end diameter is smaller than the lower end diameter. The larger-diameter end of the drainage pipe 4 is fixedly connected to the upper end of the drainage perforated pipe 5 through the stilling basin floor slab steel mesh; the upper and lower diameters of the drainage perforated pipe 5 are the same.

[0042] Step 5: Use the trapezoidal drainage pipe 4 and the drainage perforated pipe 5 as templates to pour the stilling basin floor slab concrete 12 and the anti-scour and wear-resistant concrete 13 respectively;

[0043] Among them, the lower layer pours the stilling basin floor slab concrete 12, and the upper layer pours the anti-scour and wear-resistant concrete 13.

[0044] Step 6: Fill the trapezoidal drainage pipe 4 with gravel 9. As Figure 3 shown in the figure, the inner layer of the trapezoidal drainage pipe 4 is gravel 9, and the outer layer is a concrete inner wall 10. Among them, the particle size of the gravel 9 is 1 cm. The bottom of the laid gravel 9 is 20 to 30 cm above the bottom surface of the stilling basin floor slab concrete 12, and the top of the laid gravel 9 is 15 to 20 cm below the flow surface 14.

[0045] Step 7: Pour non-sand concrete cover 11 into the trapezoidal drain pipe 4 up to the elevation of the flow-through surface 14. The non-sand concrete cover 11 is in the shape of a frustum of a cone with a larger bottom and a smaller top, and the thickness of the non-sand concrete cover 11 is 15 - 20 cm. This structural design is not easily washed out of the drain hole under the action of high-speed water flow and pulsating pressure, thereby protecting the coarse sand and gravel at the lower part of the drain pipe, and playing a role in preventing the scour and damage of the drain hole.

[0046] Example 1

[0047] The structural type of the drainage hole of the permeable floor slab of the stilling basin is as Figure 1 shown. "Trapezoidal" drainage holes are arranged on the stilling basin floor slab. The "trapezoidal" drainage hole structural type is a bottom drainage and filtration, the middle part is permeable stones, and the top is a cast-in-place frustum-shaped permeable concrete cover.

[0048] The bottom is arranged for drainage and filtration to prevent the fine particles at the pool foundation from being carried away and aggravating the seepage damage. The middle part is arranged with permeable stones to increase the water permeability of the drainage. By setting a "trapezoidal" permeable concrete cover at the top, it can not only play a role in water permeability but also ensure that the top permeable concrete cover is not washed away under the action of moving water. The structural type of the drainage hole of the permeable floor slab of the stilling basin in this application is an effective structural type for preventing blockage and scour of the drainage hole of the permeable floor slab of the stilling basin, ensuring the safety of the project.

[0049] Example 2

[0050] The construction method of the structural type of the drainage hole of the permeable floor slab of the stilling basin is as follows:

[0051] Step 1: Excavate the building foundation 1 to the designed excavation elevation 2, and arrange a sump 3 on the basis of the designed excavation elevation 2;

[0052] Step 2: Place the drainage perforated pipe 5 into the sump 3;

[0053] Step 3: Place the anti-filtration component into the drainage perforated pipe 5 and be higher than the designed excavation elevation 2;

[0054] Step 4: Connect the trapezoidal drain pipe 4 to the upper end of the drainage perforated pipe 5;

[0055] Step 5: Take the trapezoidal drain pipe 4 and the drainage perforated pipe 5 as templates, and pour the stilling basin floor slab concrete 12 and the erosion-resistant and wear-resistant concrete 13 respectively;

[0056] Step 6: Fill the trapezoidal drain pipe 4 with stones 9;

[0057] Step 7: Pour non-sand concrete cover 11 into the trapezoidal drain pipe 4 up to the elevation of the flow-through surface 14.

[0058] Example 3

[0059] Construction method for drainage hole structure type of stilling basin permeable floor slab, the specific method is as follows:

[0060] Step 1: Excavate the building foundation 1, dig out the designed excavation elevation 2, and arrange a sump 3 on the basis of the designed excavation elevation 2. The depth of the sump 3 is 50 cm;

[0061] Step 2: Place the drainage perforated pipe 5 into the sump 3;

[0062] Step 3: As shown in Figure 2 Put the filter assembly into the drainage perforated pipe 5 and make it higher than the designed excavation elevation 2; the filter assembly is specifically obtained by wrapping coarse sand 7 with non-woven filter cloth 6 and winding and fixing it with nylon rope 8. The height of the filter assembly is 20 cm higher than the designed excavation elevation 2;

[0063] Step 4: Connect the trapezoidal drain pipe 4 to the upper end of the drainage perforated pipe 5;

[0064] Step 5: Take the trapezoidal drain pipe 4 and the drainage perforated pipe 5 as templates, and pour the stilling basin floor slab concrete 12 and the erosion-resistant and wear-resistant concrete 13 respectively;

[0065] Among them, pour the stilling basin floor slab concrete 12 in the lower layer and pour the erosion-resistant and wear-resistant concrete 13 in the upper layer.

[0066] Step 6: Fill the trapezoidal drain pipe 4 with stones 9. As shown in Figure 3 The particle size of the stones 9 is 1 cm. The bottom of the laid stones 9 is 20 cm above the bottom surface of the stilling basin floor slab concrete 12, and the top of the laid stones 9 is 20 cm below the water flow surface 14.

[0067] Step 7: Pour the non-sand concrete cover 11 into the trapezoidal drain pipe 4 to the elevation of the water flow surface 14. Among them, the non-sand concrete cover 11 is a frustum structure with a larger bottom and a smaller top, and the thickness of the non-sand concrete cover 11 is 20 cm.

[0068] Example 4

[0069] Construction method for drainage hole structure type of stilling basin permeable floor slab, the specific method is as follows:

[0070] Step 1: Excavate the building foundation 1, dig out the designed excavation elevation 2, and arrange a sump 3 on the basis of the designed excavation elevation 2. The depth of the sump 3 is 100 cm;

[0071] Step 2: Place the drainage perforated pipe 5 into the sump 3;

[0072] Step 3: As shown in Figure 2As shown in the figure, the filter component is placed into the drain pipe 5 with holes and is 2 higher than the designed excavation elevation; the filter component is specifically obtained by wrapping coarse sand 7 with non-woven filter cloth 6 and fixing it with nylon rope 8 wound around, and the height of the filter component is 30 cm higher than the designed excavation elevation by 2;

[0073] Step 4: Connect the trapezoidal drain pipe 4 to the upper end of the drain pipe 5 with holes;

[0074] Step 5: Take the trapezoidal drain pipe 4 and the drain pipe 5 with holes as templates, and pour the stilling basin bottom slab concrete 12 and the erosion-resistant and wear-resistant concrete 13 respectively;

[0075] Among them, the stilling basin bottom slab concrete 12 is poured in the lower layer, and the erosion-resistant and wear-resistant concrete 13 is poured in the upper layer.

[0076] Step 6: Fill the trapezoidal drain pipe 4 with gravel 9 with a particle size of 1 cm. The bottom of the laid gravel 9 is 30 cm above the bottom surface of the stilling basin bottom slab concrete 12, and the top of the laid gravel 9 is 18 cm below the water flow surface 14.

[0077] Step 7: Pour the non-sand concrete cover 11 into the drain pipe 4 to the elevation of the water flow surface 14. Among them, the non-sand concrete cover 11 is a frustum structure with a larger bottom and a smaller top, and the thickness of the non-sand concrete cover 11 is 18 cm.

[0078] Example 5

[0079] The construction method of the drainage hole structure type of the permeable bottom slab of the stilling basin is the same as that of Example 4. The difference from Example 4 is that the depth of the sump 3 is 80 cm, the bottom of the laid gravel 9 is 25 cm above the bottom surface of the stilling basin bottom slab concrete 12, and the top of the laid gravel 9 is 15 cm below the water flow surface 14.

[0080] Example 6

[0081] The construction method of the drainage hole structure type of the permeable bottom slab of the stilling basin is the same as that of Example 4. The difference from Example 4 is that the depth of the sump 3 is 70 cm, the bottom of the laid gravel 9 is 30 cm above the bottom surface of the stilling basin bottom slab concrete 12, and the top of the laid gravel 9 is 20 cm below the water flow surface 14.

Claims

1. The structural type of drainage holes of the permeable bottom plate of the energy dissipation pool is characterized by: A "trapezoidal" drainage hole is arranged on the bottom plate of the energy dissipation pool. The "trapezoidal" drainage hole structure is a bottom drainage filter, a middle part is a permeable gravel, and a top cast-in-place truncated cone-shaped permeable concrete cover.

2. The method for constructing the structural type of drainage holes of the permeable bottom plate of the energy dissipation pool as claimed in claim 1, characterized in that: The specific method is as follows: Step 1: excavate the building foundation (1) to the designed excavation elevation (2), and lay out a water collection pit (3) based on the designed excavation elevation (2); Step 2: Place the drainage flower pipe (5) into the sump (3); Step 3: Place the filter assembly into the drainage flower pipe (5) and place it higher than the designed excavation elevation (2); Step 4: Connect the trapezoidal drainage pipe (4) to the upper end of the drainage flower pipe (5); Step 5: Using the trapezoidal drainage pipe (4) and the drainage flower pipe (5) as templates, respectively pour the energy dissipation pool bottom slab concrete (12) and the impact-resistant and wear-resistant concrete (13); Step 6: Fill the trapezoidal drainage pipe (4) with stones (9); Step 7, pouring a sandless concrete cover (11) into the trapezoidal drainage pipe (4) to the elevation of the flow surface (14); The reverse filter assembly in step 3 is specifically obtained by wrapping coarse sand (7) with a non-woven filter cloth (6) and winding and fixing it with a nylon rope (8), and the height of the reverse filter assembly is 20 cm to 30 cm higher than the designed excavation elevation (2); In step 4, the longitudinal section of the drainage pipe (4) is a trapezoidal structure, and the end with a larger diameter of the drainage pipe (4) is fixedly connected to the upper end of the drainage flower pipe (5) through a steel mesh on the bottom plate of the energy dissipation pool; The drainage flower pipe (5) has the same diameter at the top and the bottom; In step 5, the lower layer is poured with energy dissipation pool bottom slab concrete (12), and the upper layer is poured with impact-resistant and wear-resistant concrete (13); In step 6, the particle size of the gravel (9) is 1 cm, the bottom of the laid gravel (9) is located 20 to 30 cm above the bottom surface of the energy dissipation pool bottom slab concrete (12), and the top of the laid gravel (9) is located 15 to 20 cm below the flow surface (14); In step 7, the sandless concrete cover (11) is a truncated cone structure with a larger bottom and a smaller top. The thickness of the sandless concrete cover (11) is 15-20 cm.

3. The method for constructing the structural type of drainage holes of the permeable bottom plate of the energy dissipation pool according to claim 2 is characterized in that: The depth of the sump (3) in step 2 is 50 cm to 100 cm.

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