A construction method for tailings pond seepage interception dam project

Abstract

A tailings pond seepage cutoff dam construction method includes preliminary preparation, seepage cutoff dam, tailwater channel, seepage water collection pool, curtain grouting, and test inspection. The tailings pond seepage cutoff dam construction process is as follows: preliminary preparation → seepage water collection pool → curtain grouting → tailwater channel → seepage cutoff dam, wherein the seepage water collection pool and curtain grouting are carried out simultaneously, and the tailwater channel is carried out after the curtain grouting. Test inspection runs through the entire construction process. The beneficial effects of the present invention include reducing construction difficulty, improving construction progress, shortening construction time, making the seepage cutoff dam structure more stable, having high density, high strength, and good seepage cutoff performance, reducing the later repair work of the seepage cutoff dam, and increasing the service life of the seepage cutoff dam, with outstanding economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of tailings pond seepage cutoff dam construction, and in particular to a tailings pond seepage cutoff dam engineering construction method. Background Art

[0002] Most of the minerals in the tailings pond are highly polluting, and the wastewater seeping from the tailings has a great impact on the surrounding environment. Therefore, the tailings pond needs to have anti-pollution facilities. The anti-pollution facilities of the tailings pond mainly include initial dams, flood discharge facilities, seepage interception dams and other projects.

[0003] Seepage intercepting dam projects include intercepting dams, tailwater channels, collection pools, curtain grouting and other projects. Seepage intercepting dams require high seepage interception levels, are difficult to construct, require high construction technology, and require high construction precision. Traditional intercepting dams have serious water seepage, short service life, are difficult to repair, and have high repair costs. Summary of the Invention

[0004] The present invention provides a method for constructing a tailings pond seepage cutoff dam project. In order to solve the technical difficulties in the construction of a tailings pond seepage cutoff dam project, the seepage cutoff dam of the present invention adopts a concrete gravity dam, selects a filling clay gravel layer as the dam foundation bearing layer, and arranges three rows of curtain grouting holes at the bottom of the seepage cutoff dam, with a row spacing of 2m and a hole spacing of 2m, in a plum blossom-shaped arrangement. The construction difficulty of the seepage cutoff dam is reduced, the construction time is shortened, the seepage cutoff dam structure is more stable, the seepage cutoff capacity is high, the seepage cutoff repair work is less, and the service life of the seepage cutoff dam is long.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A tailings dam construction method includes preliminary preparation, a seepage dam, a tailwater channel, a seepage collection pool, curtain grouting, and testing. The construction process of the tailings dam is as follows: preliminary preparation → seepage collection pool → curtain grouting → tailwater channel → seepage dam. The seepage collection pool and curtain grouting are carried out simultaneously, and the tailwater channel is carried out after the curtain grouting. Testing runs through the entire construction process. The tailings dam construction method is as follows:

[0007] S1. Preliminary preparation

[0008] The aforementioned preliminary preparations include temporary wind, water and electricity layout, temporary roads, precipitation in the construction area, and temporary drainage of the upstream main dam;

[0009] S2. Seepage water collection pool

[0010] A seepage collection pool is provided upstream of the intercepting dam. The pool wall is protected by 40mm thick dry block stone, the pool bottom is compacted, and the water pipe inlet is reinforced concrete. The seepage collection pool is 5m long, 2.5m wide and 1.0m deep.

[0011] S3, curtain grouting

[0012] The curtain grouting holes are arranged in three rows with a row spacing of 2m and a hole spacing of 2m in a plum blossom pattern. All the curtain grouting holes are vertically drilled and drilled at least 2m below the aquitard. The curtain grouting material is cement slurry with clay slurry. The curtain grouting requirement is a permeability q≤1Lu. The curtain grouting pressure can be 0.3-0.8MPa. The grouting pressure gradually increases from top to bottom. In order to ensure the grouting quality, the grouting pressure should be high to ensure that the foundation does not lift or deform during grouting.

[0013] The construction process of the curtain grouting is as follows: measurement and layout → drilling rig in place → drilling the first section → rotating the hole, fissure flushing, water pressure test → grouting the first section → completion of the first section grouting → tank drilling the next section grouting stage → completion of the final hole grouting → sealing the hole;

[0014] S4, tailrace

[0015] A tailwater channel is provided downstream of the cut-off dam to guide water into the downstream river channel. The tailwater channel adopts a concrete structure, and the concrete adopts C25, with an anti-seepage grade of W6 and an anti-freeze grade of F300. A water diversion pipe is provided from the inside of the cut-off dam to guide water into the tailwater channel.

[0016] S5. Seepage cut-off dam

[0017] The cut-off dam is a concrete gravity dam. The cut-off dam is filled with a clay gravel layer as the dam foundation bearing layer. The topsoil is removed, and the foundation depth is not less than 2m. After the foundation is cleared, the clay gravel layer filled with the dam foundation is compacted to a compaction degree greater than 0.92. The accumulated water is removed in a timely manner. The cut-off dam is constructed in sections, with formwork installed in sections, and is constructed in layers and in a continuous flow. It is divided into 13 sections according to the standard process requirements, and commercial concrete or self-mixed concrete is used.

[0018] S6. Test and Inspection

[0019] The test and inspection described above is carried out throughout the entire construction process of the tailings dam project.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The construction method of the tailings pond seepage cut-off dam project reduces the construction difficulty, improves the construction progress, shortens the construction time, and makes the seepage cut-off dam structure more stable, with high density, high strength, and good seepage cut-off performance. It reduces the later repair work of the seepage cut-off dam, increases the service life of the seepage cut-off dam, and has outstanding economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a construction flow chart of a tailings pond seepage cutoff dam construction method described in the invention

[0023] Figure 2The present invention discloses a curtain grouting flow chart for a tailings pond seepage interception dam construction method. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0025] like Figure 1 As shown, a tailings dam construction method includes preliminary preparation, dam, tailwater channel, seepage collection pool, curtain grouting, and testing. The construction process of the tailings dam is as follows: preliminary preparation → seepage collection pool → curtain grouting → tailwater channel → dam. The seepage collection pool and curtain grouting are carried out simultaneously, and the tailwater channel is carried out after the curtain grouting. Testing runs through the entire construction process. The tailings dam construction method is as follows:

[0026] S1. Preliminary preparation

[0027] The aforementioned preliminary preparations include temporary wind, water and electricity layout, temporary roads, precipitation in the construction area, and temporary drainage of the upstream main dam;

[0028] Before the construction of the intercepting dam begins, a temporary road is built on the original road at the construction site for the construction of the concrete gravity dam. A temporary construction road is set up around the outside of the intercepting pool, that is, the upper opening of the intercepting pool slope protection.

[0029] Use large-diameter pipes for gravity dewatering. Place thirty 500mm diameter prefabricated cement pipes to lower the water level below the dam to 0.5m below the working surface. If the effect is not achieved, use a sewage pump at a well point to drain the water. After the construction is completed, use fine stone expansive concrete to seal the water.

[0030] A new seepage interception pool was built under the main dam outlet, and the drainage was led from the middle of the interception dam to the drainage ditch downstream of the concrete dam. The ditch was backfilled with gravel as a drainage blind ditch, and discharged from another temporary precipitation drainage pipe. The distance between the two pipes was 1000mm. The pipe diameter was 500mm.

[0031] S2. Seepage water collection pool

[0032] A seepage collection pool is provided upstream of the intercepting dam. The pool wall is protected by 40mm thick dry block stone, the pool bottom is compacted, and the water pipe inlet is reinforced concrete. The seepage collection pool is 5m long, 2.5m wide and 1.0m deep.

[0033] S3, curtain grouting

[0034] The curtain grouting holes are arranged in 3 rows with a row spacing of 2m and a hole spacing of 2m in a plum blossom shape. The curtain grouting holes are all vertically drilled. The curtain grouting holes are not less than 2m deep below the weak permeable layer. The curtain grouting material is cement slurry with clay slurry. The curtain grouting requirement is permeability q≤1Lu. The curtain grouting pressure can be 0.3~0.8MPa. The grouting pressure increases gradually from top to bottom. In order to ensure the quality of grouting, the grouting pressure should be high to ensure that the foundation does not lift and deform during grouting. Before the curtain grouting construction, A grouting test should be carried out. The grouting hole positions should be kept away from the transverse joints of the dam section. During construction, attention should be paid to hole layout. The distance between the hole positions and the transverse joints of the dam section should be ≥0.5m. Curtain grouting holes should all be vertically drilled, and the hole depth should be controlled by the hole bottom elevation. When the hole depth reaches the designed hole bottom elevation, if the water pressure test shows that the permeability does not meet the design requirement of q≤1Lu, the grouting hole depth should be increased until the requirement is met. Curtain grouting should first be carried out in the third row of curtain grouting holes, followed by the first row of curtain grouting holes, and finally the second row of curtain grouting holes.

[0035] like Figure 2 As shown, the construction sequence of the curtain grouting is surveying and setting out → drilling rig in place → drilling the first section → rotating the hole, fissure flushing, water pressure test → grouting the first section → completion of the first section grouting → tank drilling for the next section grouting → completion of the final hole grouting → sealing the hole;

[0036] S4, tailrace

[0037] A tailwater channel is provided downstream of the cut-off dam to guide water into the downstream river channel. The tailwater channel adopts a concrete structure, and the concrete adopts C25, with an anti-seepage grade of W6 and an anti-freeze grade of F300. A water diversion pipe is provided from the inside of the cut-off dam to guide water into the tailwater channel.

[0038] S5. Seepage cut-off dam

[0039] The cut-off dam is a concrete gravity dam. The cut-off dam is filled with a clay gravel layer as the dam foundation bearing layer. The topsoil is removed, and the foundation depth is not less than 2m. After the foundation is cleared, the clay gravel layer filled with the dam foundation is compacted to a compaction degree greater than 0.92, and accumulated water is removed in a timely manner. The cut-off dam is constructed in sections, with formwork installed in sections, and is constructed in layers and in a continuous flow. It is divided into 13 sections according to standard process requirements. Commercial concrete or self-mixed concrete is used. A concrete mixing station with a good reputation and strong transportation capacity is selected in the surrounding area to ensure continuous pouring of dam concrete.

[0040] S6. Test and Inspection

[0041] The test and inspection described above is carried out throughout the entire construction process of the tailings dam project.

[0042] The following examples are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0043] [Example]

[0044] The tailings pond seepage dam project of the 200,000-ton annual graphite concentrate beneficiation project of Luobei County Yunshan Graphite New Materials Co., Ltd. includes preliminary preparation, seepage dam, tailwater channel, seepage collection pool, curtain grouting, and testing.

[0045] like Figure 1 As shown in the figure, the construction process of the tailings pond seepage intercepting dam project is as follows: preliminary preparation → seepage collection pool → curtain grouting → tailwater channel → seepage intercepting dam. The seepage collection pool and curtain grouting are carried out simultaneously, and the tailwater channel is carried out after the curtain grouting. Tests and inspections are carried out throughout the entire construction process.

[0046] The construction method of the tailings seepage interception dam project is as follows:

[0047] S1. Preliminary preparation

[0048] The aforementioned preliminary preparations include temporary wind, water and electricity layout, temporary roads, precipitation in the construction area, and temporary drainage of the upstream main dam;

[0049] Before the construction of the intercepting dam began, the original road was occupied by the initial dam upstream of the intercepting dam and the flood discharge facility tunnel in the southeast corner. Based on the original road at the construction site, a temporary road was paved on the north side for the concrete gravity dam construction. A temporary construction road was set up around the outside of the intercepting pool, that is, the upper entrance of the intercepting pool slope protection;

[0050] Large-diameter pipes are used for gravity dewatering. Thirty 500mm diameter prefabricated cement pipes are placed at an absolute elevation of 246m below the concrete dam to lower the water level below the dam to 0.5m below the working surface. If the effect is not achieved, sewage pumps are used at wells to drain the water. After the construction is completed, fine stone expansion concrete is used to seal the water level.

[0051] A new seepage interception pool was built below the main dam outlet. The top elevation of the pool was 250m. The water was diverted from the middle of the interception dam to the drainage ditch downstream of the concrete dam. The top elevation of the pipe was 246.5m. The ditch was backfilled with gravel as a drainage blind ditch and discharged through another temporary precipitation drainage pipe. The distance between the two pipes was 1000mm, and the pipe diameter was 500mm.

[0052] S2. Seepage water collection pool

[0053] A seepage collection pool is provided upstream of the intercepting dam, with a bottom elevation of 250m and a top elevation of 254m. The pool wall is protected by 40mm thick dry block stone, the bottom of the pool is compacted, and the inlet of the water pipe is reinforced concrete. The seepage collection pool is 5m long, 2.5m wide and 1.0m deep.

[0054] S3, curtain grouting

[0055] The curtain grouting holes are arranged in 3 rows with a row spacing of 2m and a hole spacing of 2m in a plum blossom shape. The curtain grouting holes are all vertically drilled. The curtain grouting holes are not less than 2m deep below the weak permeable layer. The curtain grouting material is cement slurry with clay slurry. The curtain grouting requirement is permeability q≤1Lu. The curtain grouting pressure can be 0.3~0.8MPa. The grouting pressure increases gradually from top to bottom. In order to ensure the quality of grouting, the grouting pressure should be high to ensure that the foundation does not lift and deform during grouting. Grouting tests should be carried out before curtain grouting construction, and the grouting hole positions need to be considered. Consider avoiding the transverse joints of the dam section. During construction, attention should be paid to hole location layout. The distance between the hole location and the transverse joints of the dam section should be ≥0.5m. The curtain grouting holes are all vertically drilled, and the hole depth is controlled by the hole bottom elevation. When the hole depth reaches the designed hole bottom elevation, if the water pressure test shows that the permeability does not meet the design requirement of q≤1Lu, the grouting hole depth is required to be increased until the requirement is met. The curtain grouting should first be grouting the third row of curtain grouting holes, then the first row of curtain grouting holes, and finally the second row of curtain grouting holes. Each row of holes can be divided into three sequences. The grouting holes on both sides of the mountain are drilled from the ground.

[0056] like Figure 2 As shown, the construction sequence of the curtain grouting is surveying and setting out → drilling rig in place → drilling the first section → rotating the hole, fissure flushing, water pressure test → grouting the first section → completion of the first section grouting → tank drilling for the next section grouting → completion of the final hole grouting → sealing the hole;

[0057] S4, tailrace

[0058] A tailwater channel is provided downstream of the cut-off dam. The tailwater channel is 21 meters long and directs water into the downstream river channel. The tailwater channel adopts a concrete structure. The concrete adopts C25, anti-seepage grade W6, and anti-freeze grade F300. A water diversion pipe is provided from the inside of the cut-off dam to direct water into the tailwater channel.

[0059] S5. Seepage cut-off dam

[0060] The cut-off dam is a concrete gravity dam with an axis length of 188.13m. It is divided into a retaining dam section I, an overflow dam section, and a retaining dam section II. The retaining dam section has a dam crest elevation of 254m and a dam crest width of 1.5m. The upstream face is vertical and the downstream face has a ratio of 1:0.8. Wing walls are set on both sides, and the wing wall top elevation is 254m. The cut-off dam selects a clay gravel layer as the dam foundation bearing layer, and the top soil is removed. The foundation depth is not less than 2m. After the foundation is cleared, the clay gravel layer filled with the dam foundation is compacted with a compaction degree greater than 0.92. The accumulated water is removed in time. The cut-off dam adopts segmented construction, segmented formwork, layered and continuous construction. It is divided into 13 sections according to the standard process requirements. Commercial concrete or station-based self-mixed concrete is used to ensure continuous pouring of the dam body concrete.

[0061] S6. Test and Inspection

[0062] The test and inspection described above is carried out throughout the entire construction process of the tailings dam project.

[0063] The present invention reduces construction difficulty, improves construction progress, shortens construction time, and makes the seepage-cutting dam structure more stable, with high density, high strength, and good seepage-cutting performance. It reduces the later repair work of the seepage-cutting dam, increases the service life of the seepage-cutting dam, and has outstanding economic benefits.

Claims

1. A tailings seepage cut-off dam construction method, characterized in that: The construction process of the tailings dam is as follows: preliminary preparation, seepage dam, tailwater channel, seepage collection pool, curtain grouting, and testing. The construction process of the tailings dam is as follows: preliminary preparation → seepage collection pool → curtain grouting → tailwater channel → seepage dam. The seepage collection pool and curtain grouting are carried out simultaneously, and the tailwater channel is carried out after the curtain grouting. Testing runs through the entire construction process. The construction method of the tailings dam is as follows: S1. Preliminary preparation The aforementioned preliminary preparations include temporary wind, water and electricity layout, temporary roads, precipitation in the construction area, and temporary drainage of the upstream main dam; S2. Seepage water collection pool A seepage collection pool is provided upstream of the intercepting dam, with a bottom elevation of 250m and a top elevation of 254m. The pool wall is protected by 40mm thick dry block stone, the bottom of the pool is compacted, and the inlet of the water pipe is reinforced concrete. The seepage collection pool is 5m long, 2.5m wide and 1.0m deep. S3, curtain grouting The curtain grouting holes are arranged in three rows with a row spacing of 2m and a hole spacing of 2m in a plum blossom pattern. All the curtain grouting holes are vertically drilled and drilled at least 2m below the aquitard. The curtain grouting material is cement slurry with clay slurry. The curtain grouting requirement is a permeability q≤1Lu. The curtain grouting pressure is 0.3~0.8MPa, and the grouting pressure gradually increases from top to bottom. To ensure the grouting quality, the grouting pressure should be high to ensure that the foundation does not lift or deform during grouting. The construction process of the curtain grouting is as follows: measurement and layout → drilling rig in place → drilling the first section → rotating the hole, fissure flushing, water pressure test → grouting the first section → completion of the first section grouting → drilling the next section grouting stage → completion of the final hole grouting → sealing the hole; S4, tailrace A tailwater channel is provided downstream of the cut-off dam to guide water into the downstream river channel. The tailwater channel adopts a concrete structure, and the concrete adopts C25, with an anti-seepage grade of W6 and an anti-freeze grade of F300. A water diversion pipe is provided from the inside of the cut-off dam to guide water into the tailwater channel. S5. Seepage cut-off dam The cut-off dam is a concrete gravity dam. The cut-off dam is filled with a clay gravel layer as the dam foundation bearing layer. The topsoil is removed, and the foundation depth is not less than 2m. After the foundation is cleared, the clay gravel layer filled with the dam foundation is compacted to a compaction degree greater than 0.

92. The accumulated water is removed in a timely manner. The cut-off dam is constructed in sections, with formwork installed in sections, and is constructed in layers and in a continuous flow. It is divided into 13 sections according to the standard process requirements, and commercial concrete or self-mixed concrete is used. S6. Test and Inspection The test and inspection described above is carried out throughout the entire construction process of the tailings dam project.

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