Interception and drainage structure applicable to the interlayer dislocation zone in the underground power house

Abstract

The present invention relates to a seepage cutoff and drainage structure applicable to the interlayer shear zone in an underground power house. The purpose of the present invention is to block the passage of seepage water from the interlayer shear zone into the power house and reduce the dislocation deformation of the interlayer shear zone that may be caused by seepage water. The technical solution of the present invention is as follows: A seepage cutoff and drainage structure applicable to the interlayer shear zone in an underground power house, a grouting gallery and an anti-seepage curtain are provided on the upstream side of the underground power house, and a seepage cutoff and drainage tunnel arranged along the interlayer shear zone is provided between the anti-seepage curtain and the underground power house, and the interlayer shear zone is located in the middle of the seepage cutoff and drainage tunnel chamber; anti-filter structures are provided on the upstream and downstream of the seepage cutoff and drainage tunnel corresponding to the interlayer shear zone area, and the anti-filter structure is formed by excavating the filling materials on the upstream and downstream sides of the seepage cutoff and drainage tunnel and then backfilling with anti-filter materials. The present invention is applicable to underground space projects such as hydropower and water conservancy.

Description

Technical Field

[0001] The present invention relates to a seepage cutoff and drainage structure applicable to the interlayer dislocation zone in an underground powerhouse, and is applicable to underground space projects such as hydropower and water conservancy projects. Background Art

[0002] Affected by factors such as the deeply incised river valley topography and geomorphology conditions, and the layout of the pivot, the powerhouse of a hydropower station often adopts an underground layout form. The underground powerhouse of a hydropower project often has characteristics such as large buried depth, significant cavern group effect, high in-situ stress, and complex geological conditions. In particular, problems such as rich groundwater, developed interlayer dislocation zones or weak interlayers often pose extremely severe challenges to the surrounding rock stability and structural safety of the underground powerhouse. Therefore, the development of interlayer dislocation zones running through the underground cavern group requires sufficient attention and special research from project constructors.

[0003] Interlayer dislocation zones usually have characteristics such as low strength, poor properties, and easy softening when encountering water. If the treatment of the position of the interlayer dislocation zone is improper, after the reservoir stores water, the water in the reservoir area will seep along the interlayer dislocation zone to the underground powerhouse, and the underground powerhouse is at risk of being flooded by seepage water, which also has an adverse impact on the stability of the surrounding rock of the underground powerhouse. Since the interlayer dislocation zone is generally filled with muddy filling materials, once seepage water enters, the risk of the interlayer dislocation zone creeping and dislocating is extremely high, which will greatly affect the safety of the concrete structure of the underground powerhouse.

[0004] The existing technology for the anti-seepage construction method of the interlayer dislocation zone generally blocks water through grouting, and strengthens the grouting effect by methods such as increasing the grouting pressure of the anti-seepage curtain grouting, changing the water-cement ratio, using ultra-fine cement or chemical materials at the position of the interlayer dislocation zone. However, based on the characteristics of the interlayer dislocation zone and the anisotropy of rock mass fractures, after the reservoir stores water, the risk of underground seepage water entering the interlayer dislocation zone is still very high. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: aiming at the above problems, to provide a seepage cutoff and drainage structure applicable to the interlayer dislocation zone in an underground powerhouse, so as to block the channel for the interlayer dislocation zone to seep water into the powerhouse, and reduce the dislocation deformation of the interlayer dislocation zone that may be caused by seepage water.

[0006] The technical solution adopted by the present invention is: a seepage cutoff and drainage structure applicable to the interlayer dislocation zone in an underground powerhouse, a grouting gallery and an anti-seepage curtain are provided on the upstream side of the underground powerhouse, and it is characterized in that: an anti-seepage and drainage tunnel arranged along the interlayer dislocation zone is provided between the anti-seepage curtain and the underground powerhouse, and the interlayer dislocation zone is located in the middle of the anti-seepage and drainage tunnel chamber;

[0007] Filter structures are provided on the upstream and downstream of the anti-seepage and drainage tunnel corresponding to the interlayer dislocation zone area, and the filter structures are formed by removing the filling materials on the upstream and downstream sides of the anti-seepage and drainage tunnel and then backfilling filter materials;

[0008] The cut-off and drainage tunnel is provided with a concrete lining. A number of systematic drainage holes are arranged around the perimeter of the cut-off and drainage tunnel. One end of each systematic drainage hole extends deep into the surrounding rock mass of the cut-off and drainage tunnel, and the other end extends into the cut-off and drainage tunnel.

[0009] A number of long drainage holes are arranged at the bottom of the cut-off and drainage tunnel, and the long drainage holes communicate downward with the drainage gallery located below.

[0010] The systematic drainage holes corresponding to the position of the interlayer shear zone are arranged in a denser pattern and obliquely penetrate the interlayer shear zone upward from near the cut-off and drainage tunnel to the other end.

[0011] The systematic drainage holes corresponding to the position of the interlayer shear zone are inclined upward by 15 degrees.

[0012] The systematic drainage holes are protected by wrapping a composite plastic filter pipe with non-woven geotextile.

[0013] Each of the grouting galleries is arranged in parallel. The main anti-seepage curtain is constructed downward by using the grouting gallery. The anti-seepage curtain is slightly inclined upstream, and a connecting curtain is arranged on the upstream side wall of the grouting gallery for lapping.

[0014] The cut-off and drainage tunnel should be arranged on the downstream side of the main anti-seepage curtain, and the distance from the anti-seepage curtain line should be greater than the seepage failure path.

[0015] The beneficial effects of the present invention are as follows: The present invention provides an overall anti-seepage and drainage measure with an anti-seepage curtain for water blocking in the front and a cut-off and drainage tunnel for drainage in the back. By excavating the seepage drainage tunnel, the seepage channel from the interlayer shear zone to the power house is blocked, preventing the seepage water in the reservoir area from reaching the power house through the interlayer shear zone, and enhancing the anti-seepage effect of the underground power house. At the same time, the seepage is blocked, reducing the risk of structural damage to the power house caused by the dislocation and deformation of the interlayer shear zone.

[0016] In the present invention, to ensure that no seepage failure occurs in the interlayer shear zone and prevent the muddy filling materials contained in the interlayer shear zone from being carried away by the water flow, the filling materials are excavated at the side wall of the cut-off and drainage tunnel corresponding to the interlayer shear zone and replaced with filter materials.

[0017] In the present invention, the seepage water in the interlayer shear zone is drained into the cut-off and drainage tunnel through the systematic drainage holes, and the accumulated water in the cut-off and drainage tunnel is drained into the next-layer drainage gallery through the long drainage holes at the bottom of the cut-off and drainage tunnel. Description of the Drawings

[0018] Figure 1 It is the layout diagram along the grouting gallery of the power house for the embodiment.

[0019] Figure 2 It is the layout diagram along the water flow direction for the embodiment.

[0020] Figure 3 It is the typical cross-sectional diagram of the structure of the cut-off and drainage tunnel for the embodiment.

[0021] In the figure: 1. Base covering line; 2. Interlayer dislocation zone; 3. Underground powerhouse; 4. Grouting gallery; 5. Cut-off and drainage tunnel; 6. Drainage gallery; 7. Impervious curtain; 8. Long drainage holes; 9. System drainage holes; 10. Concrete lining; 11. Filter material. Specific implementation manner

[0022] This embodiment is a cut-off and drainage structure applicable to the interlayer dislocation zone in the underground powerhouse. According to the overall anti-seepage layout of the pivot, grouting galleries and drainage galleries that are parallel to each other are respectively arranged at different elevation positions on the upstream side of the underground powerhouse. Anti-seepage curtain grouting is constructed using the grouting galleries. Each layer of grouting galleries is arranged in parallel. The main impervious curtain is constructed downward using the grouting gallery. The impervious curtain inclines slightly upstream. The connecting curtain is arranged on the side wall of the upstream side of the grouting gallery for lapping to form a closed and complete curtain wall. The bottom penetrates into the relatively impervious layer, and the top is higher than the highest water level in the reservoir area.

[0023] In this embodiment, the impervious curtain passing through the interlayer dislocation zone adopts special treatments such as changing the grouting pressure, changing the water-cement ratio, or changing the grouting material at the position of the interlayer dislocation zone to ensure the grouting effect of the interlayer dislocation zone and strengthen the water-blocking effect of the curtain grouting.

[0024] Between the impervious curtain and the underground powerhouse, a cut-off and drainage tunnel is arranged along the interlayer dislocation zone to ensure that the interlayer dislocation zone is located in the middle of the chamber. The cut-off and drainage tunnel is arranged on the downstream side of the impervious curtain, and the distance from the impervious curtain line should be greater than the seepage failure path, and the seepage failure path should be determined through detailed calculation.

[0025] In this example, the height of the cut-off and drainage tunnel is greater than or equal to 2.5 times the width of the interlayer dislocation zone, and the width is greater than or equal to 3 times the width of the interlayer dislocation zone. The cut-off and drainage tunnel is arranged along the interlayer dislocation zone, and the range should enclose the underground powerhouse to ensure that the interlayer dislocation zone is exposed in the middle of the chamber, not less than 1 m from the bottom plate of the cut-off tunnel, and not less than 1.5 m from the top arch of the cut-off tunnel.

[0026] To ensure that no seepage failure occurs in the interlayer dislocation zone and prevent the muddy filling contained in the interlayer dislocation zone from being carried away by the water flow, the filling in the interlayer dislocation zone is excavated on the upstream and downstream side walls of the cut-off and drainage tunnel. The excavation width should be greater than 2 m, and the height is expanded 1 m upward and downward along the width of the interlayer dislocation zone. After flushing clean, it is backfilled with filter material to form a filter structure.

[0027] In this embodiment, a concrete lining is provided in the cut-off and drainage tunnel, and then filling grouting and consolidation grouting are carried out to ensure the integrity of the surrounding rock mass of the tunnel. A number of system drainage holes are arranged around the cut-off and drainage tunnel. The diameter of the drainage holes is 50 mm, the length into the rock is 3 m, and the spacing is 1.5 m × 3.0 m. The system drainage holes corresponding to the position of the interlayer dislocation zone are arranged in a denser pattern and obliquely penetrate the interlayer dislocation zone upward from the end close to the cut-off and drainage tunnel to the other end. The horizontal drainage holes are inclined upward at 15 degrees.

[0028] In this example, the system drainage holes are protected by wrapping a composite plastic filter pipe with non-woven geotextile to prevent the drainage holes from being blocked by fine particles.

[0029] In this embodiment, a drainage ditch is provided at the bottom of the cut-off and drainage tunnel. Two rows of long drainage holes are arranged in the drainage ditch. The long drainage holes are connected to the next layer of drainage gallery to drain the accumulated water in the seepage drainage tunnel.

[0030] The specific construction method of this embodiment is as follows:

[0031] According to the overall anti-seepage layout of the hub, grouting and drainage galleries parallel to each other are respectively arranged at different elevation positions on the upstream side of the underground power house. The main anti-seepage curtain grouting is constructed by using the grouting gallery. The bottom penetrates into the relatively impermeable layer, and the top is higher than the highest water level in the reservoir area;

[0032] The anti-seepage curtain penetrates through the interlayer dislocation zone. Special treatment is carried out at the position of the interlayer dislocation zone to ensure the grouting effect at the interlayer dislocation zone and strengthen the water-blocking effect of the curtain grouting;

[0033] Between the anti-seepage curtain and the main power house, a cut-off and drainage tunnel is arranged along the interlayer dislocation zone, and it is ensured that the interlayer dislocation zone is located in the middle of the chamber;

[0034] The filling materials in the interlayer dislocation zone are excavated and backfilled with replacement filter materials for the upstream and downstream side walls of the cut-off and drainage tunnel;

[0035] The cut-off and drainage tunnel is lined with concrete, and then grouting for backfilling and consolidation grouting are carried out to ensure the integrity of the surrounding rock mass of the tunnel;

[0036] System drainage holes are arranged around the cut-off and drainage tunnel. Among them, the drainage holes at the position of the interlayer dislocation zone penetrate through the interlayer dislocation zone to drain the seepage water in the interlayer dislocation zone into the seepage drainage tunnel;

[0037] Two rows of long drainage holes are arranged in the drainage ditch at the bottom of the cut-off and drainage tunnel. The drainage holes are drilled to the next layer of drainage gallery to drain the accumulated water in the seepage drainage tunnel.

Claims

1. An anti-seepage and drainage structure applicable to the interlayer dislocation zone in the underground power house. There is a grouting gallery (4) and an anti-seepage curtain (7) on the upstream side of the underground power house (3). It is characterized in that: A cut-off drainage tunnel (5) arranged along the interlayer fault zone (2) is provided between the anti-seepage curtain (7) and the underground powerhouse (3), and the interlayer fault zone (2) is located in the middle of the cut-off drainage tunnel (5) chamber; Filter structures are provided corresponding to the upper and lower regions of the interlayer fault zone (2) of the cut-off drainage tunnel (5), and the filter structures are formed by removing the filling materials on the upper and lower sides of the cut-off drainage tunnel (5) and then backfilling with filter materials (11); A concrete lining (10) is provided in the cut-off drainage tunnel (5), and a number of system drainage holes (9) are arranged around the circumference of the cut-off drainage tunnel (5). One end of the system drainage holes (9) extends deep into the surrounding rock mass of the cut-off drainage tunnel (5), and the other end extends into the cut-off drainage tunnel (5); A number of long drainage holes (8) are arranged at the bottom of the cut-off drainage tunnel (5), and the long drainage holes (8) communicate downward with the drainage gallery (6) located below; 2. The anti-seepage and drainage structure applicable to the interlayer dislocation zone in the underground power house according to claim 1, characterized in that: The system drainage holes (9) corresponding to the position of the interlayer fault zone (2) are arranged in a denser pattern and obliquely penetrate upward through the interlayer fault zone (2) from near the cut-off drainage tunnel (5) to the other end; 3. The anti-seepage and drainage structure applicable to the interlayer dislocation zone in the underground power house according to claim 2, characterized in that: The system drainage holes (9) corresponding to the position of the interlayer fault zone (2) are inclined upward by 15 degrees; 4. The anti-seepage and drainage structure applicable to the interlayer dislocation zone in the underground power house according to claim 1, characterized in that: The system drainage holes (9) are protected by wrapping a composite plastic filter pipe with a non-woven geotextile; 5. The anti-seepage and drainage structure applicable to the interlayer dislocation zone in the underground power house according to claim 1, characterized in that: Each of the grouting galleries (4) is arranged in parallel, and the main anti-seepage curtain (7) is constructed downward by using the grouting gallery (4). The anti-seepage curtain (7) is slightly inclined upstream, and a connecting curtain is arranged on the side wall of the upstream of the grouting gallery (4) for lapping; 6. The anti-seepage and drainage structure applicable to the interlayer dislocation zone in the underground power house according to claim 1, characterized in that: The cut-off drainage tunnel (5) should be arranged on the downstream side of the main anti-seepage curtain (7), and the distance from the anti-seepage curtain (7) line should be greater than the seepage failure path.

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