Cutoff wall structure for earth-rock dam weir and construction method thereof

Abstract

This invention discloses a seepage barrier wall structure and construction method for earth-rock dams. The structure and method utilize a stepped seepage barrier wall to eliminate gaps between adjacent layers of concrete seepage barrier surfaces, resulting in improved seepage prevention. The structure comprises concrete seepage barrier surfaces, seepage barrier extensions, a soil foundation, and reinforcing steel bars. Multiple layers of concrete seepage barrier surfaces are placed on the side of the soil foundation, arranged in a stepped manner along the height of the side of the soil foundation. The overlap height between adjacent layers of concrete seepage barrier surfaces is 0.3-2m. Multiple reinforcing steel bars are embedded within each concrete seepage barrier surface. The length of each reinforcing steel bar is equal to the height of the concrete seepage barrier surface, and the reinforcing steel bars are equidistantly arranged along the width of the concrete seepage barrier surface. One end of the seepage barrier extension is located on the side of the bottom layer of the concrete seepage barrier surface.

Description

Technical Field

[0001] This invention relates to a seepage barrier wall structure and construction method for earth-rock dams, which has a better seepage prevention effect. It belongs to the field of water conservancy engineering technology, and specifically relates to a seepage barrier wall structure and construction method that achieves better seepage prevention effect by using a stepped seepage barrier wall to ensure that there are no gaps between two adjacent concrete seepage barrier surfaces. Background Technology

[0002] A seepage barrier wall constructed in an earth-rock dam is a continuous underground wall that prevents water from seeping into the foundation of the dam. The current construction method for seepage barrier walls in earth-rock dams includes the following steps: 1. Leveling the site; 2. Constructing a concrete guide wall along the dam axis; 3. Excavating a deep foundation pit and filling it with bentonite slurry; 4. Excavating the trench; 5. Pouring concrete; 6. Repeating steps 3-5 to construct another deep foundation pit; 7. Sequential construction: first excavating one main face, then excavating another main face at a certain interval, pouring concrete for the two main faces, then excavating a secondary face between the two main faces and pouring concrete, until all concrete faces are connected to form the seepage barrier wall. This construction method uses the same plane as the excavation reference for the main and secondary faces, resulting in a planar seepage barrier wall. Gaps easily appear at the junction of the main and secondary faces, allowing water to seep into the earth-rock dam foundation, resulting in poor seepage prevention.

[0003] Publication No. CN117071611A discloses a seepage prevention system for earth-rock dam cofferdams and its construction method, including: a clay core wall for seepage prevention of the dam body; a plastic concrete cutoff wall, set between the clay core wall and the curtain grouting cutoff wall, for seepage prevention of the dam body and bedrock; and a curtain grouting cutoff wall, set at the lower end of the plastic concrete cutoff wall, for seepage prevention of deep bedrock. The construction method for the earth-rock dam cofferdam seepage prevention system includes the following steps: preparation of construction machinery, construction of a construction platform, and drilling of pilot holes; pre-grouting operations according to geological conditions; construction of the plastic concrete cutoff wall; curtain grouting of permeable bedrock; and filling and compaction of the clay core wall using a reciprocating slope compactor. However, although the clay core wall, plastic concrete cutoff wall and curtain grouting cutoff wall in the above-mentioned anti-seepage system and its construction method are on different horizontal levels, they are based on the same plane. The resulting anti-seepage wall is planar, and gaps are prone to appear at the junction of the upper and lower levels, which allows water to seep into the foundation of the earth-rock dam cofferdam through the gaps, resulting in poor anti-seepage effect. Summary of the Invention

[0004] To improve the above situation, the present invention provides a seepage barrier wall structure and construction method for earth-rock dams, which provides a seepage barrier wall structure and construction method that achieves better seepage prevention by using a stepped seepage barrier wall to ensure that there are no gaps between two adjacent concrete seepage barrier surfaces.

[0005] The present invention relates to a seepage barrier wall structure for earth-rock dams and its construction method as follows: The seepage barrier wall structure of the present invention for earth-rock dams consists of a concrete seepage barrier surface, a seepage barrier extension, a soil and rock foundation, and reinforcing steel bars.

[0006] The sides of the soil and rock foundation are provided with multiple layers of concrete impermeable surfaces, which are arranged in a stepped manner along the height direction of the sides of the soil and rock foundation.

[0007] Preferably, the overlap height of two adjacent concrete waterproofing layers is 0.3-2m.

[0008] The concrete impermeable surface has multiple reinforcing steel bars embedded within it.

[0009] Preferably, the length of the reinforcing steel bar is equal to the height of the concrete impermeable surface.

[0010] Preferably, the plurality of reinforcing steel bars are arranged at equal intervals along the width direction of the concrete impermeable surface.

[0011] The bottom layer of the concrete waterproof surface has a waterproof extension end on its side.

[0012] Preferably, the height of the waterproof extension gradually decreases from one end to the other.

[0013] Furthermore, the reinforcing steel bars are replaced with Y-shaped steel bars, and multiple Y-shaped steel bars are embedded in the concrete seepage-proof surface;

[0014] Preferably, the length of the Y-shaped steel bar is equal to the height of the concrete impermeable surface;

[0015] Preferably, the plurality of Y-shaped steel bars are arranged at equal intervals along the width direction of the concrete impermeable surface;

[0016] Furthermore, the seepage prevention extension is replaced by a stepped seepage prevention extension, with one end of the stepped seepage prevention extension placed on the side of the bottom concrete seepage prevention surface.

[0017] Preferably, the height of the stepped waterproof extension gradually decreases from one end to the other.

[0018] The present invention discloses a construction method for a seepage prevention wall structure for earth-rock dams, comprising the following steps:

[0019] Level the site, remove weeds, loose soil and stones from the surface, knock down protruding or easily detached parts, and fill in obvious depressions to ensure the site is flat and stable.

[0020] Construct a concrete guide wall along the dam's axis;

[0021] The first trench is excavated using impact or rotary drilling. The width of the first trench is equal to the width of the anti-seepage wall. Pre-mixed bentonite slurry is injected into the first trench. After a certain period of solidification, the bentonite slurry forms a solid grout on the borehole wall to maintain the stability of the borehole wall, remove rock cuttings, and cool and lubricate the drill bit.

[0022] Preferably, the depth of the first layer of foundation trench is one-fifth of the depth of the anti-seepage wall;

[0023] Based on the width and depth of the first layer of foundation trench, determine the quantity, specifications and location of the reinforcing steel bars. Place multiple reinforcing steel bars at equal intervals along the width of the first layer of foundation trench. Use connectors or binding tools to connect or bind the reinforcing steel bars securely to ensure that the reinforcing steel bars will not move during the subsequent concrete pouring process, thereby improving the support strength of the seepage barrier wall.

[0024] Concrete is poured into the first layer of the foundation trench to cover and completely submerge the reinforcing steel bars, forming the first layer of concrete seepage-proof surface. The poured concrete is properly cured to ensure that it hardens slowly and evenly, thereby improving its strength and seepage-proof function.

[0025] The second layer of foundation trench is excavated with the first layer of concrete seepage barrier as the reference. The width of the second layer of foundation trench is equal to the width of the seepage barrier wall. Pre-mixed bentonite slurry is poured into the second layer of foundation trench. The opening of the second layer of foundation trench is 0.3-2m higher than the bottom surface of the first layer of concrete seepage barrier.

[0026] Based on the width and depth of the second-layer foundation trench, determine the quantity, specifications, and location of the reinforcing bars. Place multiple reinforcing bars at equal intervals along the width of the second-layer foundation trench. Use connectors or binding tools to connect or bind the reinforcing bars securely. Pour concrete to cover and completely submerge the reinforcing bars, forming the second-layer concrete seepage-proof surface. The second-layer concrete seepage-proof surface is connected to the first-layer concrete seepage-proof surface.

[0027] Repeat steps (6)-(7) to drill in layers, forming the third layer of concrete anti-seepage surface, the fourth layer of concrete anti-seepage surface, and so on until all concrete anti-seepage surfaces are connected to form a stepped anti-seepage wall. This ensures that there are no gaps between the two adjacent reinforced concrete anti-seepage surfaces. The anti-seepage extension with gradually decreasing height is added to the side of the bottom concrete anti-seepage surface, resulting in a better anti-seepage effect. Beneficial effects

[0028] First, by using a stepped anti-seepage wall, there are no gaps between the two adjacent concrete anti-seepage surfaces, resulting in better anti-seepage effect.

[0029] Second, by inserting multiple reinforcing steel bars into each layer of the foundation trench, the supporting strength of the seepage-proof wall can be improved.

[0030] Third, the seepage prevention extension can increase the contact surface between the seepage prevention wall and the soil foundation, making the seepage prevention effect and compressive strength of the seepage prevention wall higher. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the anti-seepage wall structure used in earth-rock dams according to the present invention;

[0032] Figure 2 This is a schematic diagram of the anti-seepage wall structure used in earth-rock dams according to the present invention, which only shows the structure of the reinforcing steel bars;

[0033] Figure 3 This is a schematic diagram of Embodiment 2 of the present invention for the anti-seepage wall structure and construction method of earth-rock dams;

[0034] Figure 4 This is a schematic diagram of embodiment 3 of the present invention, which describes the anti-seepage wall structure and construction method for earth-rock dams.

[0035] Attached Figure

[0036] The components are: concrete seepage-proof surface (1), seepage-proof extension (2), soil and rock foundation (3), reinforcing steel bars (4), Y-shaped steel bars (5), and stepped seepage-proof extension (6). Detailed Implementation Example 1

[0037] The present invention relates to a seepage barrier wall structure for earth-rock dams and its construction method as follows: The seepage barrier wall structure for earth-rock dams of the present invention consists of a concrete seepage barrier surface (1), a seepage barrier extension (2), a soil foundation (3), and reinforcing steel bars (4).

[0038] The side of the soil foundation (3) is provided with a multi-layer concrete anti-seepage surface (1), and the multi-layer concrete anti-seepage surface (1) is arranged in a stepped manner along the height direction of the side of the soil foundation (3).

[0039] Preferably, the overlap height of two adjacent concrete waterproofing surfaces (1) is 0.3-2m.

[0040] The concrete impermeable surface (1) is embedded with multiple reinforcing steel bars (4).

[0041] Preferably, the length of the reinforcing steel bar (4) is equal to the height of the concrete impermeable surface (1).

[0042] Preferably, the plurality of reinforcing steel bars (4) are arranged at equal intervals along the width direction of the concrete impermeable surface (1).

[0043] The bottom layer of the concrete waterproof surface (1) has one end of the waterproof extension (2) on its side;

[0044] Preferably, the height of the impermeable extension (2) gradually decreases from one end to the other.

[0045] The present invention relates to a construction method for an anti-seepage wall structure for earth-rock dams, comprising the following steps:

[0046] Level the site, remove weeds, loose soil and stones from the surface, knock down protruding or easily detached parts, and fill in obvious depressions to ensure the site is flat and stable.

[0047] Construct concrete guide walls along the dam's axis;

[0048] The first trench is excavated using impact or rotary drilling. The width of the first trench is equal to the width of the anti-seepage wall. Pre-mixed bentonite slurry is injected into the first trench. After a certain period of solidification, the bentonite slurry forms a solid grout on the borehole wall to maintain the stability of the borehole wall, remove rock cuttings, and cool and lubricate the drill bit.

[0049] Preferably, the depth of the first layer of foundation trench is one-fifth of the depth of the anti-seepage wall;

[0050] Based on the width and depth of the first layer of foundation trench, determine the quantity, specifications and position of the reinforcing steel bars (4), and place multiple reinforcing steel bars (4) at equal intervals along the width direction of the first layer of foundation trench. Use connectors or binding tools to connect or bind the reinforcing steel bars (4) securely to ensure that the reinforcing steel bars (4) will not move during the subsequent concrete pouring process, thereby improving the support strength of the seepage prevention wall.

[0051] Concrete is poured into the first layer of foundation trench to cover and completely submerge the reinforcing steel bars (4) to form the first layer of concrete seepage prevention surface (1). The poured concrete is properly cured to ensure that the concrete hardens slowly and evenly, thereby improving its strength and seepage prevention function.

[0052] The second layer of foundation trench is excavated based on the first layer of concrete anti-seepage surface (1). The width of the second layer of foundation trench is equal to the width of the anti-seepage wall. The pre-mixed bentonite slurry is poured into the second layer of foundation trench. The opening of the second layer of foundation trench is 0.3-2m higher than the bottom surface of the first layer of concrete anti-seepage surface (1).

[0053] Based on the width and depth of the second layer trench, determine the quantity, specifications and position of the reinforcing steel bars (4), and place multiple reinforcing steel bars (4) at equal intervals along the width direction of the second layer trench. Use connectors or binding tools to connect or bind the reinforcing steel bars (4) securely, and pour concrete to cover and completely submerge the reinforcing steel bars (4) to form the second layer concrete seepage prevention surface (1). The second layer concrete seepage prevention surface (1) is connected to the first layer concrete seepage prevention surface (1).

[0054] Repeat steps (6)-(7) to drill in layers, forming the third layer of concrete anti-seepage surface (1), the fourth layer of concrete anti-seepage surface (1) until all concrete anti-seepage surfaces (1) are connected to form a stepped anti-seepage wall, which can make the two adjacent reinforced concrete anti-seepage surfaces (1) without gaps. On the side of the bottom concrete anti-seepage surface (1), an anti-seepage extension (2) with gradually decreasing height is added, which has a better anti-seepage effect. Example 2

[0055] The difference between this embodiment and embodiment 1 is that the reinforcing steel bar (4) is replaced with a Y-shaped steel bar (5), and the concrete anti-seepage surface (1) contains multiple Y-shaped steel bars (5). The length of the Y-shaped steel bar (5) is equal to the height of the concrete anti-seepage surface (1), and the multiple Y-shaped steel bars (5) are arranged at equal intervals along the width direction of the concrete anti-seepage surface (1). When in use, the Y-shaped steel bar (5) can increase the stress area of ​​the steel bar and has a certain deformation and torsional capacity, which can further improve the support strength of the anti-seepage wall. Example 3

[0056] The difference between this embodiment and embodiment 1 is that the seepage prevention extension (2) is replaced by a stepped seepage prevention extension (6), and one end of the stepped seepage prevention extension (6) is placed on the side of the bottom concrete seepage prevention surface (1). The height of the stepped seepage prevention extension (6) gradually decreases from one end to the other. When in use, the stepped seepage prevention extension (6) can increase the cross-sectional area of ​​seepage prevention, resulting in better seepage prevention effect. It can also increase the contact area with the horizontal rock and soil foundation (3), resulting in better water pressure resistance.

[0057] The design of overlapping height of 0.3-2m between two adjacent concrete anti-seepage surfaces (1) ensures that there are no gaps between the two adjacent concrete anti-seepage surfaces (1), resulting in better anti-seepage effect;

[0058] The design that the length of the reinforcing steel bar (4) is equal to the height of the concrete anti-seepage surface (1) can further improve the supporting strength of the anti-seepage wall.

[0059] The goal is to achieve a better seepage prevention effect by ensuring that there are no gaps between the two adjacent concrete seepage prevention surfaces (1) through the stepped seepage prevention wall.

[0060] It should be noted that, unless otherwise explicitly specified and limited, the terms "placed," "connected," and "linked" should be interpreted broadly. For example, they can refer to fixed connections such as folded edges, rivets, pins, adhesives, and welds; detachable connections such as threaded connections, snap-fit ​​connections, and hinges; integral connections; electrical connections; direct connections; or indirect connections via an intermediate medium; or internal connections between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0061] It should be further noted that, in order to keep the description simple and clear, the above specific embodiments only describe the differences between them and other embodiments. However, those skilled in the art should know that the above specific embodiments are also independent technical solutions.

Claims

1. A construction method for a diaphragm wall structure of an earth and rockfill dam weir, characterized by: The following steps are included: (1) Leveling the site, removing weeds, loose soil and stones from the site surface, knocking down protruding and easily detached parts, filling in obvious depressions, and ensuring the flatness and stability of the site; (2) Constructing a concrete guide wall along the dam axis; (3) Excavating the first layer of foundation trench using impact or rotary drilling. The width of the first layer of foundation trench is equal to the width of the anti-seepage wall. Pre-mixed bentonite slurry is injected into the first layer of foundation trench. After a certain period of time, the bentonite slurry solidifies and forms a solid grouting body on the borehole wall to maintain the stability of the borehole wall, remove rock cuttings, and cool and lubricate the drill bit; (4) According to The width and depth of the first layer of foundation trench are determined, and the quantity, specifications and location of the reinforcing bars are determined. Multiple reinforcing bars are placed at equal intervals along the width direction of the first layer of foundation trench. The reinforcing bars are connected or tied firmly using connectors or binding tools to ensure that the reinforcing bars will not move during the subsequent concrete pouring process, thereby improving the support strength of the anti-seepage wall; (5) Concrete is poured into the first layer of foundation trench to cover and completely submerge the reinforcing bars, forming the first layer of concrete anti-seepage surface. The poured concrete is properly cured to ensure that the concrete hardens slowly and evenly, thereby improving its strength and anti-seepage function; (6) With The second layer of foundation trench is excavated based on the first layer of concrete anti-seepage surface. The width of the second layer of foundation trench is equal to the width of the anti-seepage wall. Pre-mixed bentonite slurry is poured into the second layer of foundation trench. The opening of the second layer of foundation trench is 0.3-2m higher than the bottom surface of the first layer of concrete anti-seepage surface. (7) According to the width and depth of the second layer of foundation trench, the quantity, specifications and position of the reinforcing steel bars are determined. Multiple reinforcing steel bars are placed at equal intervals along the width direction of the second layer of foundation trench. The reinforcing steel bars are connected or tied firmly using connectors or binding tools. Concrete is poured to cover and completely submerge the reinforcing steel bars to form the second layer of concrete anti-seepage surface. The second layer of concrete seepage prevention surface is connected to the first layer of concrete seepage prevention surface; (8) Repeat steps (6)-(7), drill in layers to form the third layer of concrete seepage prevention surface, the fourth layer of concrete seepage prevention surface, and so on until all concrete seepage prevention surfaces are connected to form a stepped seepage prevention wall, which can make the gaps between the two adjacent reinforced concrete seepage prevention surfaces. The seepage prevention extension with gradually decreasing height is added to the side of the bottom concrete seepage prevention surface, and the seepage prevention effect is better. The multiple layers of concrete seepage prevention surfaces are arranged in a stepped manner along the height direction of the side of the rock and soil foundation. The height of the overlap between two adjacent concrete seepage prevention surfaces is 0.3-2m.

2. A construction method of a cutoff wall structure for an earth and rockfill dam according to claim 1, characterized in that The depth of the first layer of foundation trench is one-fifth of the depth of the anti-seepage wall.

3. A construction method of a cutoff wall structure for an earth and rockfill dam according to claim 1, characterized in that The seepage barrier structure used for earth-rock dams consists of a concrete seepage barrier surface, a seepage barrier extension, a soil and rock foundation, and reinforcing steel bars. The sides of the soil and rock foundation are provided with multiple layers of concrete seepage barrier surfaces, each of which contains multiple reinforcing steel bars. The bottom layer of the concrete seepage barrier surface has one end of the seepage barrier extension on its side.

4. A construction method of a cutoff wall structure for an earth and rockfill dam according to claim 3, characterized in that The reinforcing steel bars are replaced with Y-shaped steel bars, and multiple Y-shaped steel bars are embedded in the concrete anti-seepage surface; the length of the Y-shaped steel bars is equal to the height of the concrete anti-seepage surface; the multiple Y-shaped steel bars are arranged at equal intervals along the width direction of the concrete anti-seepage surface.

5. A construction method for a seepage prevention wall structure for earth-rock dams according to claim 3, characterized in that... The seepage-proof extension is replaced with a stepped seepage-proof extension, with one end of the stepped seepage-proof extension located on the side of the bottom concrete seepage-proof surface; the height of the stepped seepage-proof extension gradually decreases from one end to the other. The stepped seepage-proof extension can increase the cross-sectional area of ​​the seepage-proofing, resulting in better seepage prevention, and can also increase the contact area with the horizontal rock and soil foundation, thus improving water pressure resistance.

6. A construction method of a cutoff wall structure for earth and rockfill dam according to claim 3, characterized in that The height of the seepage-proof extension gradually decreases from one end to the other.

7. A construction method for a seepage-proof wall structure for earth-rock dams according to claim 3, characterized in that... The length of the reinforcing steel bar is equal to the height of the concrete impermeable surface.

8. A method of constructing a diaphragm wall structure for an earth and rockfill dam according to claim 3, wherein Multiple reinforcing bars are arranged at equal intervals along the width of the concrete impermeable surface.

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