Methods for ecological restoration and treatment of abandoned mine water and pollution prevention and sealing structures

Abstract

This invention proposes a method and pollution-prevention sealing structure for the ecological restoration and treatment of abandoned mine water. Based on geological conditions, the sealing location is determined within the main adit of the mine, and the inner wall of the main adit at that location is excavated. A retaining wall is constructed in front of the sealing location, and a through-flow drainage steel pipe is pre-embedded within the retaining wall. Anchor bolts are driven into the surrounding rock at the sealing location in the main adit, and a casting template and reinforcing cage are laid out at the sealing location. The reinforcing cage is welded and fixed to the anchor bolts, and then concrete is poured. The cross-sectional shape of the concrete plug matches the cross-sectional shape of the main adit. The concrete plug is a wedge-shaped structure with a cross-sectional area that initially remains constant and then gradually decreases from front to back. The rear end of the drainage steel pipe extends through the concrete plug. After the concrete plug reaches its curing time, contact grouting is performed to fill the gap between the concrete plug and the inner wall of the main adit. This invention, using a wedge-shaped plug, significantly improves the safety of the surrounding rock and reduces the difficulty of the sealing construction.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration and treatment of abandoned mine water, and particularly to a method for sealing and pollution-preventing sealing of abandoned mine water for ecological restoration and treatment. Background Technology

[0002] Currently, with the exploitation of mineral resources, mines have altered the original groundwater system. Due to the closure of numerous mines in China, a large number of abandoned mines have been created. After the closure of coal mines, most of the groundwater flows out from the main adit of the mine. During the outflow process, the heavy metal ions, sulfate ions, suspended solids, and other pollutants carried by the water cause significant pollution to the surrounding environment. It is urgent to implement pollution containment measures to treat some of the water-bearing mines.

[0003] Conventional methods for preventing pollution in mines have problems such as poor safety, high construction difficulty, and poor isolation effect. Even after sealing treatment, mines still have significant environmental pollution risks. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention aims to provide a method for ecological restoration and treatment of abandoned mine water and a pollution prevention and sealing structure, so as to solve the problems of difficult construction, poor stability and safety of existing sealing methods.

[0005] To achieve the above objectives, this invention proposes a method for ecological restoration and sealing of abandoned mine water, comprising the following steps:

[0006] S1. Based on geological conditions, determine the sealing location 20-50m away from the mine entrance in the main adit of the mine, and expand the inner wall of the main adit at the sealing location to form a wedge-shaped structure with the cross-sectional area remaining unchanged from front to back and then gradually decreasing.

[0007] S2. Backfill and consolidate the inner wall of the main adit at the sealing location to improve the bearing capacity of the surrounding rock mass and prevent the formation of seepage channels; and set up a water retaining wall in front of the sealing location to block the water coming into the tunnel, which facilitates the sealing construction; and pre-embed a drainage steel pipe that runs through the front and rear of the water retaining wall to drain the water blocked by the water retaining wall. The drainage steel pipe is equipped with a butterfly valve at the end of the drainage steel pipe.

[0008] S3. Open the butterfly valve to drain water. Install anchor bolts in the surrounding rock at the sealing position of the main adit. Lay out the casting template and steel cage at the sealing position. Weld the steel cage to the anchor bolts and fix them together. Then start pouring concrete. The cast concrete plug extends longitudinally with an extension length of 8-12m. The cross-sectional shape of the concrete plug matches the cross-sectional shape of the main adit. The concrete plug is a wedge-shaped structure with a cross-sectional area that remains unchanged from front to back and then gradually decreases. The outer contour of the rear end of the concrete plug shall not be smaller than the inner contour of the main adit at the corresponding position. The circumferential safety distance between the outer contour of the front end and the inner contour of the main adit at the corresponding position shall be at least 1m. The rear end of the drainage steel pipe passes through the concrete plug.

[0009] S4. After the concrete plug reaches the required curing time, contact grouting is performed to fill the gap between the concrete plug and the inner wall of the main adit, eliminating the risk of leakage at the contact surface. After the construction is completed, the butterfly valve is closed.

[0010] In the above scheme: a pressure sensor is installed inside the drainage steel pipe, and this pressure sensor is electrically connected to an alarm device outside the mine. The pressure sensor is used to monitor the water pressure at the front end of the concrete plug. When the detected water pressure is too high, the alarm device will issue an alarm signal. After receiving the alarm signal, the staff can open the butterfly valve to release the pressure.

[0011] In the above scheme: the end of the drainage steel pipe extends to the outside of the mine and is connected to the sewage treatment facility. The sewage in front of the retaining wall is transported to the outside of the mine through the drainage steel pipe, and then treated by the sewage treatment facility, which can effectively prevent water pollution in abandoned mines.

[0012] In the above scheme: the drainage steel pipe between the concrete plug and the sewage treatment mechanism is encased in concrete, and the concrete shell protects the drainage steel pipe.

[0013] In the above solution, the extension length of the concrete plug is 10m, which is a relatively short construction length. This ensures the sealing effect while effectively shortening the construction period and saving costs.

[0014] In the above scheme, the ratio of the length of the section with a constant cross-sectional area to the length of the section with a gradually decreasing cross-sectional area in the concrete plug is 1:5. This setting makes the concrete plug have good pressure resistance.

[0015] In the above scheme, the concrete plug is placed 25-35m away from the mine entrance. The surrounding rock at the entrance is generally quite fractured, which is not conducive to the placement of the concrete plug, while placing the concrete plug too far from the entrance will result in poor sealing effect.

[0016] This invention also proposes a pollution prevention and sealing structure for abandoned mine water, comprising a concrete plug installed inside the main adit of the mine to seal it. The concrete plug extends longitudinally and is positioned 20-50m from the mine entrance, with an extension length of 8-12m. The cross-sectional shape of the concrete plug matches the cross-sectional shape of the main adit. The concrete plug is a wedge-shaped structure with a cross-sectional area that initially remains constant and then gradually decreases from front to back. The front end of the concrete plug has a width of 6m and a height of 6.5m, and the rear end has a width of 2m and a height of 2.5m. The front end of the plug is equipped with a water-retaining wall with a steep slope. The concrete plug is made of a steel cage and concrete. The outer contour of the rear end of the concrete plug shall not be less than the inner contour of the main adit of the mine at the corresponding position. The circumferential safety distance between the outer contour of the front end and the inner contour of the main adit of the mine at the corresponding position shall be at least 1m. A drainage steel pipe running through the front and rear is pre-embedded in the water-retaining wall. The rear end of the drainage steel pipe passes through the concrete plug. A butterfly valve is installed at the end of the drainage steel pipe. Anchor rods are installed in the surrounding rock at the sealing position of the main adit. The steel cage and the anchor rods are welded together.

[0017] The beneficial effects of this invention are: 1. The use of wedge-shaped plugs significantly improves the safety of the surrounding rock. Wedge-shaped plugs effectively reduce the maximum principal stress and Mises stress within the rock mass, providing better stress conditions than cylindrical plugs. Furthermore, the wedge-shaped concrete plugs are constructed using a reinforced concrete cage, which is then welded and fixed to the anchor rods driven into the surrounding rock. This design greatly enhances the tensile strength of the concrete plugs, effectively preventing breakage damage. 2. By completely sealing the passage with concrete plugs, air is prevented from entering, thus preventing sulfides inside the tunnel from contacting the air, avoiding the formation of iron sulfide oxidation, and inhibiting the reaction of acidic water. 3. Due to the constant presence of water in the tunnel, a retaining wall is installed before pouring the concrete plug to block the incoming water. A drainage steel pipe is pre-embedded in the retaining wall, allowing the incoming water in front of the retaining wall to be discharged. This makes concrete pouring more convenient and faster in a waterless environment. After the concrete plug is poured, the rear end of the drainage steel pipe extends out of the concrete plug. Normally, the butterfly valve can be closed to stop the drainage steel pipe from draining water. However, when the water pressure at the front of the concrete plug is too high, the butterfly valve can be opened to discharge the sewage in the tunnel to relieve pressure and ensure the stability of the concrete plug. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the longitudinal section of the concrete plug.

[0019] Figure 2 This is a schematic diagram of the cross-section of a concrete plug. Detailed Implementation

[0020] like Figure 1 As shown in Figure 2, a method for ecological restoration and sealing of abandoned mine water mainly consists of the following steps:

[0021] S1. Based on geological conditions, determine the sealing location 20-50m away from the mine entrance in the main adit of the mine, and expand the inner wall of the main adit at the sealing location to form a wedge-shaped structure with the cross-sectional area remaining unchanged from front to back and then gradually decreasing.

[0022] S2. Backfill and consolidate the inner wall of the main adit at the sealing location to improve the bearing capacity of the surrounding rock mass and prevent the formation of seepage channels; and set up a water retaining wall 2 in front of the sealing location to block the water coming into the tunnel, which facilitates the sealing construction; and pre-embed a drainage steel pipe 3 that runs through the front and rear of the water retaining wall 2 to drain the water blocked by the water retaining wall 2. The drainage steel pipe 3 is equipped with a butterfly valve 4 at the end of the drainage steel pipe 3.

[0023] S3. Open butterfly valve 4 to drain water. Install anchor rods 5 in the surrounding rock at the sealing position of the main adit. Lay out the casting template and steel cage at the sealing position. Weld the steel cage to the anchor rods 5 and fix them together. Then start pouring concrete. The cast concrete plug 1 extends longitudinally with an extension length of 8-12m. The cross-sectional shape of the concrete plug 1 matches the cross-sectional shape of the main adit. The concrete plug 1 is a wedge-shaped structure with a cross-sectional area that remains unchanged from front to back and then gradually decreases. The outer contour of the rear end of the concrete plug 1 shall not be less than the inner contour of the main adit at the corresponding position. The circumferential safety distance B between the outer contour of the front end and the inner contour of the main adit at the corresponding position shall be at least 1m. The rear end of the drainage steel pipe 3 passes through the concrete plug 1.

[0024] S4. After the concrete plug 1 reaches the required curing time, contact grouting is performed to fill the gap between the concrete plug and the inner wall of the main adit, eliminating the risk of leakage at the contact surface. After the construction is completed, the butterfly valve 4 is closed.

[0025] In the above scheme: a pressure sensor is installed inside the drainage steel pipe 3, and the pressure sensor is electrically connected to the alarm device outside the mine. The pressure sensor is used to monitor the water pressure at the front end of the concrete plug 1. When the water pressure is detected to be too high, the alarm device will issue an alarm signal. When the staff receives the alarm signal, they can open the butterfly valve 4 to release the pressure.

[0026] Ideally, the end of the drainage steel pipe 3 extends outside the mine and connects to the sewage treatment facility. The sewage in front of the retaining wall is transported to the outside of the mine through the drainage steel pipe 3, and then treated by the sewage treatment facility, which can effectively prevent water pollution in abandoned mines.

[0027] Ideally, the drainage steel pipe 3 between the concrete plug 1 and the sewage treatment unit should be encased in concrete, with the concrete shell protecting the drainage steel pipe 3.

[0028] Ideally, the extension length of the concrete plug 1 should be 10m, which is a relatively short construction length. This ensures the sealing effect while effectively shortening the construction period and saving costs.

[0029] Ideally, in the concrete plug 1, the ratio of the length of the section with a constant cross-sectional area to the length of the section with a gradually decreasing cross-sectional area is 1:5. This arrangement ensures that the concrete plug 1 has good pressure-bearing capacity.

[0030] Ideally, the concrete plug 1 should be placed 25-35m from the mine entrance. The surrounding rock at the entrance is generally quite fractured, which is not conducive to the placement of the concrete plug 1. However, placing the concrete plug 1 too far from the entrance will result in poor sealing effect.

[0031] A pollution prevention and sealing structure for abandoned mine water includes a concrete plug 1 installed inside the main adit of the mine to seal it. The concrete plug 1 extends longitudinally and is located 20-50m from the mine entrance, with an extension length of 8-12m. The cross-sectional shape of the concrete plug 1 matches the cross-sectional shape of the main adit. The concrete plug 1 is a wedge-shaped structure with a cross-sectional area that remains constant from front to back and then gradually decreases. The front end of the concrete plug 1 is 6m wide and 6.5m high, and the rear end is 2m wide and 2.5m high. The concrete plug 1 is constructed by reinforcing a cage and pouring concrete. Anchor bolts 5 are driven into the surrounding rock at the sealing location of the main adit, and the reinforcing cage and anchor bolts 5 are welded together. The outer contour of the rear end of the concrete plug 1 must not be smaller than the inner contour of the corresponding location of the main adit, and the circumferential safety distance B between the outer contour of the front end and the inner contour of the corresponding location of the main adit is at least 1m. A water-retaining wall 2 is provided at the front end of the concrete plug 1, and the front end of the water-retaining wall 2 is set with a steep slope. A drainage steel pipe 3 that runs through the front and back is pre-embedded in the water-retaining wall 2. The rear end of the drainage steel pipe 3 passes through the concrete plug 1, and a butterfly valve 4 is provided at the end of the drainage steel pipe 3.

[0032] The use of wedge-shaped plugs significantly improves the safety of the surrounding rock. Wedge-shaped plugs effectively reduce the maximum principal stress and Mises stress within the rock mass, providing better stress conditions than cylindrical plugs. Furthermore, the wedge-shaped concrete plug 1 is constructed by reinforcing a cage and pouring concrete, with the cage welded to the anchor rods 5 driven into the surrounding rock. This design greatly enhances the tensile strength of the concrete plug 1, effectively preventing breakage damage. Because wedge-shaped plugs have excellent support and sealing performance, a length of 8–12 m is sufficient for sealing, whereas cylindrical plugs require a length of 20–40 m. Therefore, using wedge-shaped plugs for sealing also effectively shortens the construction period and reduces construction costs.

Claims

1. A method for ecological restoration and sealing of abandoned mine water, characterized in that: The structure includes a pollution prevention and sealing structure for abandoned mine water. This structure comprises a concrete plug (1) installed within the main adit of the mine to seal it. The concrete plug (1) extends longitudinally and is positioned 20-50m from the mine entrance. The extension length of the concrete plug (1) is 8-12m. The cross-sectional shape of the concrete plug (1) matches the cross-sectional shape of the main adit. The concrete plug (1) is a wedge-shaped structure with a cross-sectional area that initially remains constant and then gradually decreases from front to back. The front end of the concrete plug (1) has a width of 6m and a height of 6.5m, and the rear end has a width of 2m and a height of 2.5m. A [further details about the structure are missing]. There is a retaining wall (2), the front end of the retaining wall (2) is set with a steep slope, the concrete plug (1) is made of steel cage and concrete pouring, the outer contour of the rear end of the concrete plug (1) shall not be less than the inner contour of the main adit of the mine at the corresponding position, the circumferential safety distance (B) between the outer contour of the front end and the inner contour of the main adit of the mine at the corresponding position is at least 1m, a drainage steel pipe (3) is pre-embedded in the retaining wall (2) and the rear end of the drainage steel pipe (3) passes through the concrete plug (1), a butterfly valve (4) is provided at the end of the drainage steel pipe (3), and an anchor rod (5) is installed in the surrounding rock at the sealing position of the main adit, and the steel cage and the anchor rod (5) are welded together; The sealing method includes the following steps: S1. Based on the geological conditions, determine the sealing position in the main adit of the mine, 20-50m away from the mine entrance, and expand the inner wall of the main adit at the sealing position to form a wedge-shaped structure with the cross-sectional area remaining unchanged from front to back and then gradually decreasing. S2. Backfill grouting and consolidation grouting are carried out on the inner wall of the main adit at the sealing location to improve the bearing capacity of the surrounding rock mass and avoid the formation of seepage channels; and a water retaining wall (2) is set in front of the sealing location. The water retaining wall (2) can block the water coming from the tunnel, which is convenient for sealing construction; a drainage steel pipe (3) is pre-embedded in the water retaining wall (2) to drain the water blocked by the water retaining wall (2). A butterfly valve (4) is provided at the end of the drainage steel pipe (3); the end of the drainage steel pipe (3) extends to the outside of the mine and is connected to the sewage treatment facility. S3. Open the butterfly valve (4) to drain water. Install anchor rods (5) in the surrounding rock at the sealing position of the main adit. Set up the casting template and steel cage at the sealing position. Weld the steel cage and anchor rods (5) together. Then start pouring concrete. The cast concrete plug (1) extends longitudinally with an extension length of 8~12m. The cross-sectional shape of the concrete plug (1) matches the cross-sectional shape of the main adit. The concrete plug (1) is a wedge structure with the cross-sectional area remaining unchanged from front to back and then gradually decreasing. The outer contour of the rear end of the concrete plug (1) shall not be less than the inner contour of the main adit at the corresponding position. The circumferential safety distance (B) between the outer contour of the front end and the inner contour of the main adit at the corresponding position shall be at least 1m. The rear end of the drainage steel pipe (3) passes through the concrete plug (1). S4. After the concrete plug (1) reaches the required age, contact grouting is carried out to fill the gap between the concrete plug and the inner wall of the main adit, eliminating the risk of leakage at the contact surface. After the construction is completed, the butterfly valve (4) is closed.

2. The method for ecological restoration, treatment, and sealing of abandoned mine water according to claim 1, characterized in that: A pressure sensor is installed inside the drainage steel pipe (3), and the pressure sensor is electrically connected to the alarm device outside the mine.

3. The method for ecological restoration, treatment, and sealing of abandoned mine water according to claim 2, characterized in that: The drainage steel pipe (3) between the concrete plug (1) and the sewage treatment unit is encased in concrete.

4. The method for ecological restoration, treatment, and sealing of abandoned mine water according to claim 1, characterized in that: The concrete plug (1) has an extension length of 10m.

5. The method for ecological restoration, treatment, and sealing of abandoned mine water according to claim 4, characterized in that: In the concrete plug (1), the ratio of the length of the section with a constant cross-sectional area to the length of the section with a gradually decreasing cross-sectional area is 1:

5.

6. The method for ecological restoration, treatment, and sealing of abandoned mine water according to claim 1, characterized in that: The concrete plug (1) is located 25-35m from the mine entrance.

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