Under-dam drainage structure of a leach field

Abstract

This application discloses a drainage structure beneath the initial dam of an ash storage yard, comprising an initial dam, a slope-adhering drainage layer located on the slope front of the initial dam, and a drainage cushion layer located at the slope toe. A drainage pipe is installed at the bottom of the initial dam, with the inlet end of the drainage pipe extending into the drainage cushion layer and the outlet end of the drainage pipe connected to a recovery tank. The beneficial effects of this application are: compared to a normal initial dam drainage layer, this drainage structure ensures that ash water and seepage from the ash storage yard are not discharged or leaked, while also lowering the seepage line within the initial dam, ensuring dam stability. The overall structure is simple, reliable, easy to construct, and low in cost.

Description

Technical Field

[0001] This application belongs to the technical field of seepage prevention and drainage design optimization for the initial dam of an ash storage yard in a thermal power plant, specifically involving a drainage structure downstream of the initial dam of an ash storage yard. Background Technology

[0002] The ash storage yard of a thermal power plant is a storage site for ash and slag produced after coal combustion power generation in a thermal power plant when comprehensive utilization is not feasible. The initial dam is mainly an initial ash-blocking dam body built in the ash storage yard for ash storage. It is an important structure in the ash storage yard, similar to a combination of a water-blocking dam in a hydropower plant and a municipal retaining wall. It needs to take into account both the functions of ash blocking and water blocking.

[0003] The most important environmental protection requirement for ash storage sites is strict seepage prevention, ensuring that untreated ash water does not leak or discharge. However, from an engineering safety perspective, the initial dam is similar to a retaining dam (retaining wall), requiring drainage and seepage control measures to lower the water level for engineering safety. This contradicts environmental protection requirements. Therefore, we need to find an initial dam drainage and seepage control structure that can guarantee strict seepage prevention in the ash storage site. Utility Model Content

[0004] The purpose of this application is to provide a drainage structure downstream of the initial dam of an ash storage site, which solves the problem of combining the water-blocking and drainage functions of the initial dam.

[0005] The objective of this application is achieved through the following technical solution:

[0006] A drainage structure for the initial dam of an ash storage site includes an initial dam, a slope-adhering drainage layer located on the slope and a drainage mattress layer located at the toe of the slope in front of the initial dam, a drainage pipe passing through the bottom of the initial dam, the inlet end of the drainage pipe extending into the drainage mattress layer, and the outlet end of the drainage pipe connected to a recycling pool.

[0007] Furthermore, the slope drainage layer includes an HDPE geomembrane impermeable layer, a coarse stone drainage layer on top of the HDPE geomembrane impermeable layer, a geotextile filter layer on top of the coarse stone drainage layer, and a permeable slope protection layer on top of the geotextile filter layer.

[0008] Furthermore, the slope-adhering drainage layer also includes a compacted fine soil and stone protective layer, the lower layer of which is adhered to the initial dam, the upper layer of which is adhered to an HDPE geomembrane anti-seepage layer, the upper layer of which is adhered to a pebble protective layer, the upper layer of which is adhered to a coarse stone drainage layer, the upper layer of which is adhered to a pebble protective layer, the upper layer of which is adhered to a geotextile filter layer, the upper layer of which is adhered to a pebble protective layer, and the upper layer of which is adhered to a permeable slope protection layer, wherein the permeable slope protection layer is a dry-laid rubble protective layer.

[0009] Furthermore, the drainage mattress layer includes an HDPE geomembrane impermeable layer, a coarse stone drainage layer is provided on the upper layer of the HDPE geomembrane impermeable layer, a geotextile filter layer is provided on the upper layer of the coarse stone drainage layer, a permeable slope protection layer is provided on the upper layer of the geotextile filter layer, and the drainage pipe passes through the HDPE geomembrane impermeable layer and extends into the coarse stone drainage layer.

[0010] Furthermore, the drainage mattress layer also includes a sodium-based expansive soil waterproof felt protective layer, a lower layer of which is bonded to the substrate, an upper layer of which is bonded to an HDPE geomembrane impermeable layer, an upper layer of which is bonded to a geotextile filter layer, an upper layer of which is bonded to a pebble protective layer, an upper layer of which is bonded to a coarse stone drainage layer, an upper layer of which is bonded to a pebble protective layer, an upper layer of which is bonded to a geotextile filter layer, an upper layer of which is bonded to a pebble protective layer, and an upper layer of which is bonded to a permeable slope protection layer, wherein the permeable slope protection layer is a dry-laid rubble protective layer.

[0011] Furthermore, the drainage pipeline includes a drainage perforated pipe located within the drainage mattress layer. The drainage perforated pipe is connected to the drainage light pipe at the bottom of the initial dam, the drainage light pipe is connected to the water collection pipe behind the initial dam, and the water collection pipe is connected to the recycling pool.

[0012] Furthermore, the drainage pipes are arranged in a grid pattern.

[0013] Furthermore, the initial dam is a roller-compacted earth-rock dam body, with drainage pipes running through the roller-compacted earth-rock dam body. The lower layer of the roller-compacted earth-rock dam body is bonded to a pebble protective layer, the lower layer of the pebble protective layer is bonded to a geotextile filter layer, the lower layer of the geotextile filter layer is bonded to a pebble protective layer, the lower layer of the pebble protective layer is bonded to a replacement roller-compacted stone layer, and the lower layer of the replacement roller-compacted stone layer is bonded to a clay layer.

[0014] Furthermore, a rockfill prism is provided behind the initial dam, and a bank slope drainage ditch is provided at the rear of the rockfill prism.

[0015] Furthermore, the initial dam area was equipped with pedestrian walkways and sloping horse trails.

[0016] The beneficial effects of this application are as follows: Compared with the normal initial dam drainage layer, this drainage structure ensures that the ash water and seepage water in the ash storage yard are not discharged or leaked. At the same time, it can also reduce the seepage line in the initial dam, ensuring the stability of the dam body. The overall structure is simple, reliable, easy to construct and has a low cost.

[0017] The aforementioned main solution and its various further alternatives can be freely combined to form multiple solutions, all of which are solutions that can be adopted and claimed in this application; furthermore, the (non-conflicting alternatives) can also be freely combined with each other and with other alternatives. Those skilled in the art, after understanding this solution, will realize from the prior art and common general knowledge that there are many combinations, all of which are technical solutions to be protected in this application, and will not be exhaustively listed here. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of the structure of this application.

[0019] Figure 2 This is the structural plan of this application.

[0020] Figure 3 This is a cross-sectional view of the drainage mattress layer structure of this application.

[0021] Figure 4 This is the main view of the drainage pipe structure in this application.

[0022] Figure 5 This is a side view of the drainage pipe structure of this application.

[0023] In the diagram: 1-Initial dam, 2-Slope drainage layer, 3-Drainage mattress layer, 4-Rockfill prism, 5-Drainage pipe, 6-Recycling pond, 7-Compacted earth-rock dam body, 8-Compacted fine soil and stone protective layer, 9-HDPE geomembrane seepage prevention layer, 10-Pebble protective layer, 11-Coarse stone drainage layer, 12-Geotextile filter layer, 13-Dry-laid rubble protective layer, 14-Base, 15-Sodium-based expansive soil waterproof felt protective layer, 16-Replacement compacted stone layer, 17-Clay layer, 18-Drainage perforated pipe, 19-Drainage smooth pipe, 20-Water collection pipe, 21-Clearing baseline, 22-Slope drainage ditch, 23-Original ground line, 24-Slope toe line, 25-Pedestrian walkway, 26-Sloping horse trail. Detailed Implementation

[0024] The present application will be further described below with reference to specific embodiments and accompanying drawings.

[0025] Example

[0026] The ash storage site of a thermal power plant is located in the southwest, an area with heavy rainfall and large upstream water flow. Strict drainage measures are required upstream of the initial dam to lower the phreatic line and ensure the safety of the ash storage site. Traditional initial upstream drainage and seepage control measures mainly involve slope drainage and drainage mats below the dam. However, ash water in the ash storage site must be strictly controlled. If conventional drainage methods are used, the ash water will disperse unorganizedly into the rockfill behind the initial dam after passing through the slope drainage and drainage mats below the dam, making centralized collection and treatment of the ash water impossible and causing environmental pollution.

[0027] refer to Figures 1-5 As shown, a drainage structure under the initial dam of an ash storage site includes an initial dam 1, a slope-adhering drainage layer 2, a drainage cushion layer 3, a rockfill prism 4, a drainage pipeline 5, and a recycling pool 6.

[0028] The initial dam 1 has a slope-adhering drainage layer 2 located on the slope and a drainage cushion layer 3 located at the toe of the slope. The slope-adhering drainage layer 2 blocks and guides the accumulated grey water and seepage water on the slope, allowing the stored water to flow down the slope to the toe. The drainage cushion layer 3 at the toe blocks the accumulated grey water and seepage water, preventing excessive water infiltration of the dam body and affecting its stability.

[0029] A drainage pipe 5 is installed at the bottom of the initial dam 1 to facilitate the internal discharge of water stored at the slope toe. The inlet end of the drainage pipe 5 extends into the drainage mattress layer 3, and the outlet end of the drainage pipe 5 is connected to the recycling pool 6. Thus, the water stored inside the drainage mattress layer 3 flows to the rear of the dam through the drainage pipe 5 and finally flows into the recycling pool 6 for unified collection and treatment, avoiding environmental problems caused by external discharge and leakage. At the same time, it can also reduce the seepage line inside the initial dam and ensure the stability of the dam body.

[0030] The slope-adhering drainage layer 2 includes an HDPE geomembrane impermeable layer 9, a coarse rock drainage layer 11 on top of the HDPE geomembrane impermeable layer 9, a geotextile filter layer 12 on top of the coarse rock drainage layer 11, and a permeable slope protection layer on top of the geotextile filter layer 12. The permeable slope protection layer protects the initial dam face stability and prevents erosion. The geotextile filter layer ensures that seepage water does not carry away fine ash particles when passing through the drainage pores, preventing seepage damage such as quicksand. The coarse rock drainage layer is the main channel for seepage drainage, while the HDPE geomembrane impermeable layer below it is used for seepage prevention in the ash field, preventing ash water leakage. After passing through the above-mentioned slope-adhering drainage layer, the ash water is discharged to the dam toe through the coarse rock drainage layer.

[0031] The slope drainage layer 2 specifically includes, from bottom to top, the following layers arranged in sequence: compacted fine soil and stone protective layer 8, HDPE geomembrane seepage prevention layer 9, pebble protective layer 10, coarse stone drainage layer 11, pebble protective layer 10, geotextile filter layer 12, pebble protective layer 10, and permeable slope protection layer.

[0032] The lower layer of the compacted fine soil and stone protective layer 8 is bonded to the initial dam 1. The upper layer of the compacted fine soil and stone protective layer 8 is bonded to the HDPE geomembrane anti-seepage layer 9. The upper layer of the HDPE geomembrane anti-seepage layer 9 is bonded to the pebble protective layer 10. The upper layer of the pebble protective layer 10 is bonded to the coarse stone drainage layer 11. The upper layer of the coarse stone drainage layer 11 is bonded to the pebble protective layer 10. The upper layer of the pebble protective layer 10 is bonded to the geotextile filter layer 12. The upper layer of the geotextile filter layer 12 is bonded to the pebble protective layer 10. The upper layer of the pebble protective layer 10 is bonded to the permeable slope protection layer, which is a dry-laid rubble protective layer 13.

[0033] The drainage mattress layer 3 includes an HDPE geomembrane impermeable layer 9, a coarse rock drainage layer 11 on top of the HDPE geomembrane impermeable layer 9, a geotextile filter layer 12 on top of the coarse rock drainage layer 11, and a permeable slope protection layer on top of the geotextile filter layer 12. Drainage pipes 5 pass through the HDPE geomembrane impermeable layer 9 and extend into the coarse rock drainage layer 11. The drainage mattress layer is located at the lowest point of the initial dam toe, and its structure is basically the same as that of the slope-adhering drainage layer. Drainage pipes are installed within the coarse rock drainage layer of the drainage mattress layer. By connecting to the slope-adhering drainage system in front of the dam, lime water can be discharged into the lowest coarse rock drainage layer within the lime pit, and then collected through the drainage pipes.

[0034] The drainage mattress layer 3 specifically includes, from bottom to top, a sodium-based expansive soil waterproof felt protective layer 15, an HDPE geomembrane seepage prevention layer 9, a geotextile filter layer 12, a pebble protective layer 10, a coarse stone drainage layer 11, a pebble protective layer 10, a geotextile filter layer 12, a pebble protective layer 10, and a permeable slope protection layer.

[0035] The lower layer of the sodium-based expansive soil waterproof felt protective layer 15 is bonded to the base 14. The upper layer of the sodium-based expansive soil waterproof felt protective layer 15 is bonded to the HDPE geomembrane anti-seepage layer 9. The upper layer of the HDPE geomembrane anti-seepage layer 9 is bonded to the geotextile filter layer 12. The upper layer of the geotextile filter layer 12 is bonded to the pebble protective layer 10. The upper layer of the pebble protective layer 10 is bonded to the coarse stone drainage layer 11. The upper layer of the coarse stone drainage layer 11 is bonded to the pebble protective layer 10. The upper layer of the pebble protective layer 10 is bonded to the geotextile filter layer 12. The upper layer of the geotextile filter layer 12 is bonded to the pebble protective layer 10. The upper layer of the pebble protective layer 10 is bonded to the permeable slope protection layer, which is a dry-laid rubble protective layer 13.

[0036] The drainage pipe 5 includes a drainage perforated pipe 18, which is a pipe with perforations at the top, preferably made of flexible hose. The drainage perforated pipe 18 is located within the drainage mattress layer 3 and is used to collect water within the coarse stone drainage layer of the drainage mattress layer. The drainage perforated pipe 18 is arranged in a grid pattern to ensure uniform water collection.

[0037] The drainage pipe 18 is connected to the drainage pipe 19 at the bottom of the initial dam 1. Several drainage pipes 19 are arranged to transport the water stored in front of the dam to the area behind the dam. The drainage pipe 19 is a non-perforated pipe, preferably made of flexible hose. The drainage pipe 19 is connected to the water collection pipe 20 behind the initial dam 1. The water collection pipe 20 is connected to the recovery pool 6. The water collection pipe 20 is made of steel pipe and collects the water stored in the drainage pipes 19, which then flows into the recovery pool 6 for unified treatment.

[0038] The drainage pipes arranged within the coarse-grained stone drainage layer of the drainage mattress are permeable hoses with perforations on the upper layer, collecting lime water through these perforations. The initial drainage pipes at the bottom of the dam are normal, impermeable, and perforated hoses. The drainage hoses can be welded through the HDPE geomembrane impermeable layer to ensure reliable seepage prevention in the lime silo. The water collection pipes behind the dam are lime water seepage drainage steel pipes, impermeable and without perforations, ensuring no leakage of lime water.

[0039] The initial dam 1 is a roller-compacted earth-rock dam body 7. The drainage pipeline 5 is installed inside the roller-compacted earth-rock dam body 7. The lower layer of the roller-compacted earth-rock dam body 7 is bonded to a pebble protective layer 10. The lower layer of the pebble protective layer 10 is bonded to a geotextile filter layer 12. The lower layer of the geotextile filter layer 12 is bonded to the pebble protective layer 10. The lower layer of the pebble protective layer 10 is bonded to a replacement roller-compacted stone layer 16. The lower layer of the replacement roller-compacted stone layer 16 is bonded to a clay layer 17.

[0040] The initial dam 1 has a rockfill prism 4 behind it, and a bank slope drainage ditch 22 is provided at the rear of the rockfill prism 4. The initial dam 1 has a pedestrian walkway 25 and a ramp 26.

[0041] The foregoing basic examples and their further alternative examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed in this application. In the scheme of this application, each alternative example can be arbitrarily combined with any other basic example and alternative example.

[0042] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A drainage structure downstream of an initial dam in an ash storage yard, comprising an initial dam (1), characterized in that: The initial dam (1) is provided with a slope-adhering drainage layer (2) on the slope and a drainage mattress layer (3) at the foot of the slope. A drainage pipe (5) is installed at the bottom of the initial dam (1). The inlet end of the drainage pipe (5) extends into the drainage mattress layer (3), and the outlet end of the drainage pipe (5) is connected to the recycling pool (6).

2. The drainage structure downstream of the initial dam of the ash storage yard according to claim 1, characterized in that: The slope drainage layer (2) includes an HDPE geomembrane seepage prevention layer (9), a coarse stone drainage layer (11) is provided on the upper layer of the HDPE geomembrane seepage prevention layer (9), a geotextile filter layer (12) is provided on the upper layer of the coarse stone drainage layer (11), and a permeable slope protection layer is provided on the upper layer of the geotextile filter layer (12).

3. The drainage structure downstream of the initial dam of the ash storage yard according to claim 2, characterized in that: The slope drainage layer (2) also includes a compacted fine soil and stone protective layer (8), the lower layer of the compacted fine soil and stone protective layer (8) is attached to the initial dam (1), the upper layer of the compacted fine soil and stone protective layer (8) is attached to the HDPE geomembrane anti-seepage layer (9), the upper layer of the HDPE geomembrane anti-seepage layer (9) is attached to the pebble protective layer (10), the upper layer of the pebble protective layer (10) is attached to the coarse stone drainage layer (11), the upper layer of the coarse stone drainage layer (11) is attached to the pebble protective layer (10), the upper layer of the pebble protective layer (10) is attached to the geotextile filter layer (12), the upper layer of the geotextile filter layer (12) is attached to the pebble protective layer (10), the upper layer of the pebble protective layer (10) is attached to the permeable slope protection layer, and the permeable slope protection layer is a dry-laid stone protective layer (13).

4. The drainage structure downstream of the initial dam of the ash storage yard according to claim 1, characterized in that: The drainage mattress layer (3) includes an HDPE geomembrane impermeable layer (9), a coarse stone drainage layer (11) is provided on the upper layer of the HDPE geomembrane impermeable layer (9), a geotextile filter layer (12) is provided on the upper layer of the coarse stone drainage layer (11), a permeable slope protection layer is provided on the upper layer of the geotextile filter layer (12), and a drainage pipe (5) passes through the HDPE geomembrane impermeable layer (9) and extends into the coarse stone drainage layer (11).

5. The drainage structure downstream of the initial dam of the ash storage yard according to claim 4, characterized in that: The drainage mattress layer (3) also includes a sodium-based expansive soil waterproof felt protective layer (15), the lower layer of the sodium-based expansive soil waterproof felt protective layer (15) is bonded to the base (14), the upper layer of the sodium-based expansive soil waterproof felt protective layer (15) is bonded to the HDPE geomembrane seepage prevention layer (9), the upper layer of the HDPE geomembrane seepage prevention layer (9) is bonded to the geotextile filter layer (12), the upper layer of the geotextile filter layer (12) is bonded to the pebble protective layer (10), the upper layer of the pebble protective layer (10) is bonded to the coarse stone drainage layer (11), the upper layer of the coarse stone drainage layer (11) is bonded to the pebble protective layer (10), the upper layer of the pebble protective layer (10) is bonded to the geotextile filter layer (12), the upper layer of the geotextile filter layer (12) is bonded to the pebble protective layer (10), the upper layer of the pebble protective layer (10) is bonded to the permeable slope protection layer, and the permeable slope protection layer is a dry-laid stone protective layer (13).

6. The drainage structure downstream of the initial dam of the ash storage yard according to claim 1, characterized in that: The drainage pipeline (5) includes a drainage flower pipe (18), which is located inside the drainage mattress layer (3). The drainage flower pipe (18) is connected to the drainage light pipe (19) at the bottom of the initial dam (1). The drainage light pipe (19) is connected to the water collection pipe (20) behind the initial dam (1). The water collection pipe (20) is connected to the recycling pool (6).

7. The drainage structure downstream of the initial dam of the ash storage yard according to claim 6, characterized in that: The drainage pipe (18) is arranged in a grid pattern.

8. The drainage structure downstream of the initial dam of the ash storage yard according to claim 1, characterized in that: The initial dam (1) is a compacted earth-rock dam (7). The drainage pipe (5) is installed inside the compacted earth-rock dam (7). The lower layer of the compacted earth-rock dam (7) is attached to the pebble protective layer (10). The lower layer of the pebble protective layer (10) is attached to the geotextile filter layer (12). The lower layer of the geotextile filter layer (12) is attached to the pebble protective layer (10). The lower layer of the pebble protective layer (10) is attached to the replacement compacted stone slag layer (16). The lower layer of the replacement compacted stone slag layer (16) is attached to the clay layer (17).

9. The drainage structure downstream of the initial dam of the ash storage site according to claim 1 or 8, characterized in that: The initial dam (1) is provided with a rockfill prism (4) behind the dam, and a bank slope drainage ditch (22) is provided at the rear of the rockfill prism (4).

10. The drainage structure downstream of the initial dam of the ash storage yard according to claim 1 or 8, characterized in that: The initial dam (1) is equipped with a pedestrian walkway (25) and a ramp (26).

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