Underwater dump-fill isolation dam and implementation method thereof

Abstract

The present invention relates to an underwater dump-fill isolation dam structure and an implementation method thereof. The purpose of the present invention is to provide an underwater dump-fill isolation dam and an implementation method thereof, so as to solve the impact of new dam construction on the existing operation of the reservoir and the difficult problems of construction diversion and interception. The technical solution of the present invention is: an underwater dump-fill isolation dam, characterized in that: the isolation dam is located on a soil foundation, the isolation dam body is divided into two parts: an underwater dump-fill dam body and an above-water rolling construction dam body, and a vertical anti-seepage structure arranged along its axis is provided in the dam body, the vertical anti-seepage structure includes curtain grouting arranged in a rock foundation below the soil foundation, an anti-seepage wall arranged in the soil foundation and the underwater dump-fill dam body, and a cast-in-place concrete core wall arranged in the above-water rolling construction dam body. The present invention is suitable for projects that need to form independent reservoirs by building dams around existing reservoirs, rivers and other water areas.

Description

Technical Field

[0001] The present invention relates to an underwater dump-fill isolation dam structure and its implementation method, which is suitable for projects where an independent reservoir needs to be formed by building a dam around an existing reservoir, river or other water area. Background Art

[0002] With the continuous development of urbanization, some reservoirs originally built in the wilderness have gradually been surrounded by cities and become water supply reservoirs to ensure urban water supply. In order to prevent rainwater and sewage from newly built cities in the periphery from entering the reservoirs, it is necessary to build isolation projects in the rivers where sewage enters the reservoirs. In addition, after long-term operation, the functions of existing reservoirs may change due to changes in the external environment. For example, when part of an existing reservoir is used to build a pumped storage power station, when conflicting operational requirements arise, it is also necessary to build isolation dams to functionally separate the reservoirs. By building isolation dams in existing reservoirs, a reservoir can be divided into several independently operable reservoirs. It is necessary to address the impact of new dam construction on the existing operation of the reservoir and the difficulties of construction diversion and interception. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: in response to the above-mentioned problems, an underwater dump-fill isolation dam and its implementation method are provided to solve the impact of new dam construction on the existing operation of the reservoir and the difficulties of construction diversion and interception.

[0004] The technical solution adopted by the present invention is: an underwater dump fill isolation dam, characterized in that: the isolation dam is located on a soil foundation, the isolation dam body is divided into two parts: an underwater dump fill dam body and an above-water rolling construction dam body, and the dam body is provided with a vertical anti-seepage structure arranged along its axis, the vertical anti-seepage structure includes curtain grouting arranged in the rock foundation below the soil foundation, an anti-seepage wall arranged in the soil foundation and the underwater dump fill dam body, and a cast-in-place concrete core wall arranged in the above-water rolling construction dam body.

[0005] The underwater dumping dam body is composed of a collapse zone, a slag dumping zone, a fine stone mixed dumping zone, an anti-seepage wall, a fine stone mixed dumping zone, a slag dumping zone and a collapse zone from upstream to downstream.

[0006] The fine stone mixed throwing area uses concrete materials made of clay and slag with a maximum particle size of 20 cm and a soil-stone ratio of 2:3 to 1:1; the slag filling area and the collapse area use slag with a maximum particle size of no more than 80 cm.

[0007] The slag material is required to have a saturated uniaxial compressive strength of not less than 30 MPa, be slightly weathered to fresh rock, and have a good particle size distribution.

[0008] The water rolling construction dam body is composed of a rockfill area, a transition material area, a cast-in-place concrete core wall, a transition material area and a rockfill area from upstream to downstream.

[0009] The cast-in-situ concrete core wall extends to above the dam top to form a wave-breaking wall.

[0010] A bank spillway is provided on the bank at one end of the isolation dam, connecting the upstream and downstream parts of the isolation dam. The bank spillway comprises an inlet channel, a control section and an outlet channel from upstream to downstream. The control section comprises a lower lock chamber and an upper opening and closing machine room.

[0011] The curtain grouting extends to below the lower gate chamber, and the anti-seepage wall and the cast-in-situ concrete core wall extend to the lower gate chamber and are connected to the side wall of the lower gate chamber via a water-stop structure.

[0012] The side wall surface of the lower lock chamber close to the side of the isolation dam body is a vertical surface.

[0013] The water-stop structure has an enlarged end of an anti-seepage wall, which is tightly attached to the side wall of the lower gate chamber and connected to the anti-seepage wall and the cast-in-place concrete core wall to form a whole; a plurality of saddle holes are drilled from top to bottom corresponding to the gap between the enlarged end of the anti-seepage wall and the lower gate chamber, and water-soluble polyurethane is poured into the saddle holes.

[0014] A method for implementing the underwater dump-fill isolation dam is characterized by comprising the following steps:

[0015] A temporary cofferdam I is built near the shore to create a dry land construction environment for the bank floodgate;

[0016] Carry out excavation of the spillway foundation and build a bank spillway connecting the upstream and downstream of the isolation dam according to structural requirements;

[0017] On the wall of the lower chamber of the bank flood discharge gate on the side close to the isolation dam, with the center line of the anti-seepage wall as the control line, a semi-circular steel pipe protective cover is installed close to the side wall of the lower chamber and fixed to the side wall of the lower chamber through temporary fixing measures. The diameter of the steel pipe protective cover is slightly larger than the thickness of the anti-seepage wall;

[0018] In the foundation pit of the lower lock chamber on the side of the isolation dam, rubble is backfilled in layers by rolling to the top elevation of the underwater dump dam body. The steel pipe protective cover is fixed by rubble, and the temporary fixing measures are removed from bottom to top as the rubble backfill rises;

[0019] After using temporary cofferdam II to block the upstream and downstream of the control section in the flood discharge gate flow channel on the opposite bank, temporary cofferdam I was dismantled;

[0020] According to the designed dimensions of the dam body and the material requirements of each area, the underwater filling is carried out from both banks to the middle or from one bank to the other bank using the advance method to form the underwater filling dam body;

[0021] After the underwater dumping and filling dam body construction is completed, the slag dumping area and fine stone mixed dumping area of ​​the underwater dumping and filling dam body are reinforced by dynamic compaction method;

[0022] Construct the slots for the cut-off wall and cast the cut-off wall. After the slots on the outer side of the semicircular steel pipe protective cover are formed, the solid wall slurry used in the cut-off wall construction is used to replace the accumulated water in the semicircular steel pipe protective cover. The semicircular steel pipe protective cover is then lifted using a lifting device. The solid wall slurry in the protective cover stabilizes the slot wall at the expanded end of the cut-off wall, allowing the slots in the cut-off wall to extend to the side wall of the lower gate chamber.

[0023] After the cut-off wall is formed, the dam foundation curtain grouting construction is carried out from the top of the cut-off wall;

[0024] The dam body is constructed by rolling on water. After the construction of the cut-off wall is completed, the construction platform on the top of the cut-off wall is removed, the mud-containing concrete on the top of the cut-off wall is chiseled out, the steel mesh of the upper cast-in-place concrete core wall is tied and overlapped with the steel mesh of the cut-off wall, and the cast-in-place concrete core wall is cast in the formwork;

[0025] After the concrete core wall is cast in place and the dam body on both sides is rolled and filled to the dam crest elevation, multiple seam holes are drilled from the dam crest downwards to correspond to the gap between the enlarged end of the anti-seepage wall and the lower gate chamber. Water-soluble polyurethane is poured into the seam holes to form water stop plugs, forming an "8"-shaped water stop structure.

[0026] Continue pouring the upper wave-breaking wall portion of the cast-in-place concrete core wall;

[0027] Carry out foundation consolidation grouting and curtain grouting construction of the lower chamber floor;

[0028] Remove after the lower lock chamber is ready for water retention

[0029] Temporary cofferdam II will be removed after the construction of the lower lock chamber is completed.

[0030] The beneficial effects of the present invention are as follows: the present invention constructs a new reservoir on an existing water area through an underwater dump-fill isolation dam, which has the advantages of simple construction and diversion and low investment, and realizes the functional division of the original reservoir without affecting the operation of the existing reservoir, further increasing the service scope, service capacity or service quality of the reservoir.

[0031] The present invention utilizes underwater dump filling technology and dynamic compaction treatment process to ensure that the underwater dump filling dam body meets the performance requirements of permanent operation; a vertical anti-seepage structure with multiple combinations of anti-seepage wall + cast-in-place concrete core wall + curtain grouting is used to provide an efficient anti-seepage effect for the dam body; and a lateral anti-seepage connection between the anti-seepage wall, cast-in-place concrete core wall and the lower gate chamber concrete structure is achieved through a drilled water-stop structure.

[0032] The present invention utilizes the bank flood discharge gate to achieve the coordinated cooperation of reservoir functions under special working conditions and the flood control safety of the newly built reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a floor plan diagram of an embodiment.

[0034] Figure 2 It is a typical cross-sectional view of the dam body of the underwater dump-fill isolation dam in the embodiment.

[0035] Figure 3 It is a transverse cross-sectional view of an embodiment.

[0036] Figure 4 Schematic diagram of the connection between the cut-off wall and the lower lock chamber in the embodiment.

[0037] In the figure: 1. Bank; 2. Reservoir area; 3-1. Slag dumping area; 3-2. Fine stone mixed dumping area; 3-3. Collapse area; 3-4. Rockfill filling area; 3-5. Transition material area; 3-6. Curtain grouting; 3-7. Anti-seepage wall; 3-8. Cast-in-place concrete core wall; 4. Control section; 4-1. Lock chamber; 4-2. Superstructure; 5. Inlet channel; 6. Outlet channel; 7-1. Temporary cofferdam I; 7-2. Temporary cofferdam II; 8. Rock foundation; 9. Soil foundation; 10. Water-stop structure; 10-1. Semicircular steel pipe protective cover; 10-2. Cross-joint hole; 10-3. Water-stop plug; 12. Backfill concrete in foundation pit; 13. Rockfill body; 14. Slot. DETAILED DESCRIPTION

[0038] This embodiment has an underwater dump-fill isolation dam set on the reservoir area to serve as water retaining and isolation, and a shore flood discharge gate set on the shore to connect the upstream and downstream of the underwater dump-fill isolation dam.

[0039] In this example, the underwater dump fill isolation dam is located on an earth foundation. Based on the water level during construction, it is divided into two parts: the underwater dump fill dam body and the water-rolled construction dam body. The underwater dump fill isolation dam body is equipped with a vertical anti-seepage structure arranged along its axis. This vertical anti-seepage structure includes curtain grouting in the rock foundation below the earth foundation, an anti-seepage wall installed in the earth foundation and the underwater dump fill dam body, and a cast-in-place concrete core wall installed in the water-rolled construction dam body. The anti-seepage wall is located in the middle of the underwater dump fill isolation dam body, on the higher water level (upstream) side.

[0040] In this embodiment, the underwater dump fill dam body is designed according to the underwater stable body shape, the anti-seepage wall construction requirements and the possible slope collapse during operation. The underwater dump fill dam body is composed of the collapse zone, slag dumping zone, fine stone mixed dumping zone, anti-seepage wall, fine stone mixed dumping zone, slag dumping zone and collapse zone from upstream to downstream. The fine stone mixed dumping zone adopts concrete materials of clay and slag materials with a maximum particle size of 20cm and a soil-rock ratio of 2:3 to 1:1. The slag dumping area 3-1 and the upstream and downstream collapse areas 3-3 use slag materials with a maximum particle size of no more than 80cm. The slag material of the dumping fill is required to have a saturated uniaxial compressive strength of not less than 30MPa, weakly weathered to fresh rock, and good particle grading.

[0041] In this example, the dam body was designed using a layered rolling compaction process. The cast-in-place concrete core is flanked by transitional material areas, and the outer areas are filled with rockfill. The cast-in-place concrete core extends above the dam crest to form a wave barrier.

[0042] In this embodiment, the bank spillway consists of an inlet channel, a control section, and an outlet channel, from upstream to downstream. The control section includes the lower lock chamber and the upper opening and closing machine room located above the lower lock chamber. The control section is located on the rock foundation of the reservoir bank. Curtain grouting is used within the rock foundation for anti-seepage treatment. This curtain grouting connects with the curtain grouting below the underwater dump-fill isolation dam. In this embodiment, the side wall of the lower lock chamber on the side closest to the dam body is a vertical surface and is connected to the anti-seepage wall and cast-in-place concrete core wall within the dam body through a waterstop structure.

[0043] In this embodiment, the water-stop structure has an enlarged end of an anti-seepage wall, which is in close contact with the side wall of the lower gate chamber and is connected to the anti-seepage wall and the cast-in-place concrete core wall to form a whole; two 200mm diameter saddle holes are drilled from top to bottom corresponding to the gap between the enlarged end of the anti-seepage wall and the lower gate chamber, and water-soluble polyurethane is poured into the saddle holes to form water-stop plugs, which are combined into an "8"-shaped water-stop structure.

[0044] The specific construction method of this embodiment is as follows:

[0045] Under the condition that the normal operation of the reservoir is not affected, the reservoir water level shall be appropriately lowered, and according to the relationship between the water level and the foundation of the bank spillway, a temporary cofferdam I shall be built close to the bank to form a dry land construction environment for the bank spillway;

[0046] Excavate the foundation of the floodgate and build the floodgate according to the structural requirements, including the inlet channel, control section and outlet channel. Backfill the foundation pit of the lower gate chamber in the control section of the floodgate on the side close to the reservoir bank with concrete;

[0047] On the wall of the lower gate chamber in the flood discharge gate control section, close to the dam body, a semicircular steel pipe protective cover is installed close to the side wall of the lower gate chamber, with the center line of the anti-seepage wall as the control line. The center of the semicircular steel pipe protective cover is located on the center line of the anti-seepage wall, and it is temporarily fixed with bolts and other measures. The diameter of the steel pipe protective cover is slightly larger than the thickness of the anti-seepage wall.

[0048] The foundation pit of the lower lock chamber on the side of the dam body is backfilled with slag in layers, compacted and rolled to the top elevation of the underwater dump dam body. The semi-circular steel pipe protective cover on the side wall of the lower lock chamber is fixed with the slag, and the temporary fixing measures are continuously removed from bottom to top as the slag filling layer rises.

[0049] After using temporary cofferdam II to block the upstream and downstream sections of the control section in the flood discharge gate flow channel, temporary cofferdam I was dismantled;

[0050] According to the designed dimensions of the dam body and the material requirements of each area, underwater filling is carried out from both banks to the middle or from one bank to the other bank using the advance method, including the collapsed area, the slag filling area and the fine stone mixed filling area near the core wall;

[0051] After completing the underwater filling construction, the slag filling area and the fine stone mixed filling area are reinforced by dynamic compaction method;

[0052] Construct the slots for the anti-seepage wall and cast the anti-seepage wall; the slot construction boundary near the side of the lower gate chamber is kept at a certain safety distance from the semi-circular steel pipe protective cover to prevent collision and mutual damage between the drilling equipment and the semi-circular steel pipe protective cover; after the slots outside the semi-circular steel pipe protective cover are formed, the solid wall slurry used in the anti-seepage wall construction is used to replace the accumulated water in the semi-circular steel pipe protective cover, and the semi-circular steel pipe protective cover is lifted using a lifting device. The solid wall slurry in the protective cover protects the anti-seepage wall from expanding and stabilizing the slot wall, thereby extending the slots of the anti-seepage wall to the side wall of the lower gate chamber;

[0053] After the cut-off wall is formed, the dam foundation curtain grouting construction is carried out from the top of the cut-off wall;

[0054] The dam body is constructed by rolling compaction on water. After the construction of the cut-off wall is completed, the top cut-off wall construction platform is dismantled, the mud-containing concrete on the top of the cut-off wall is chiseled out, the steel mesh of the upper cast-in-situ concrete core wall is tied and overlapped with the steel mesh of the cut-off wall, and the cast-in-situ concrete core wall is cast in the formwork along the upper roller-compacted rockfill area and transition material area, rising layer by layer.

[0055] After the dam body and cast-in-place concrete core wall are constructed to the dam crest elevation, two 200mm diameter holes are drilled from the dam crest to correspond to the gap between the enlarged end of the anti-seepage wall and the lower gate chamber. Water-soluble polyurethane is poured into the holes to form water stop plugs, forming an "8"-shaped water stop structure, and the top is sealed.

[0056] Continue pouring the upper wave-breaking wall of the cast-in-place concrete core wall;

[0057] Carry out foundation consolidation grouting and curtain grouting construction of the lower chamber floor;

[0058] Construct the internal structure of the lower lock chamber and the upper traffic bridge, working bridge, gate slot, gate, hoist, bent frame or upper machine room, etc., and dismantle the temporary cofferdam II upstream and downstream of the lock chamber;

[0059] Construction of pavement structure and slope protection, etc.

Claims

1. An underwater dump-fill isolation dam, characterized by: The isolation dam is located on an earth foundation. The dam body is divided into two parts: an underwater dump fill dam body and an above-water roller compaction dam body. A vertical anti-seepage structure is arranged along the dam body's axis. The vertical anti-seepage structure includes curtain grouting in the rock foundation below the earth foundation, anti-seepage walls in the earth foundation and underwater dump fill dam body, and a cast-in-place concrete core wall in the above-water roller compaction dam body. A bank spillway is provided on the bank at one end of the isolation dam, connecting the upstream and downstream of the isolation dam. The bank spillway comprises an inlet channel, a control section and an outlet channel from upstream to downstream. The control section includes a lower lock chamber and an upper machine room. The curtain grouting extends to the bottom of the lower lock chamber, and the anti-seepage wall and cast-in-place concrete core wall extend to the lower lock chamber and connect to the side wall of the lower lock chamber through the water stop structure; On the wall of the lower chamber of the bank flood discharge gate on the side close to the isolation dam, with the center line of the anti-seepage wall as the control line, a semi-circular steel pipe protective cover is installed close to the side wall of the lower chamber and fixed to the side wall of the lower chamber through temporary fixing measures. The diameter of the steel pipe protective cover is greater than the thickness of the anti-seepage wall; The side wall of the lower lock chamber close to the isolation dam body is a vertical surface; The water-stop structure has an enlarged end of an anti-seepage wall, which is tightly attached to the side wall of the lower gate chamber and connected to the anti-seepage wall and the cast-in-place concrete core wall to form a whole; a plurality of saddle holes are drilled from top to bottom corresponding to the gap between the enlarged end of the anti-seepage wall and the lower gate chamber, and water-soluble polyurethane is poured into the saddle holes.

2. The underwater dump-fill isolation dam according to claim 1, characterized in that: The underwater dumping dam body is composed of a collapse zone, a slag dumping zone, a fine stone mixed dumping zone, the anti-seepage wall, a fine stone mixed dumping zone, a slag dumping zone and a collapse zone from upstream to downstream.

3. The underwater dump-fill isolation dam according to claim 2, characterized in that: The fine stone mixed throwing area uses concrete materials made of clay and slag with a maximum particle size of 20 cm and a soil-stone ratio of 2:3 to 1:1; the slag filling area and collapse area use slag with a maximum particle size of no more than 80 cm.

4. The underwater dump-fill isolation dam according to claim 3, characterized in that: The slag material is required to have a saturated uniaxial compressive strength of not less than 30 MPa, be slightly weathered to fresh rock, and have a good particle size distribution.

5. The underwater dump-fill isolation dam according to claim 1, characterized in that: The water rolling construction dam body is composed of a rockfill area, a transition material area, the cast-in-place concrete core wall, a transition material area and a rockfill area from upstream to downstream.

6. The underwater dump-fill isolation dam according to claim 1 or 5, characterized in that: The cast-in-situ concrete core wall extends to above the dam top to form a wave-breaking wall.

7. A method for implementing the underwater dump-fill isolation dam according to any one of claims 1 to 6, characterized in that: The following steps are involved: A temporary cofferdam I is built near the shore to create a dry land construction environment for the bank floodgate; Carry out foundation excavation of bank spillway and build bank spillway connecting upstream and downstream of isolation dam according to structural requirements; On the wall of the lower chamber of the bank flood discharge gate on the side close to the isolation dam, with the center line of the anti-seepage wall as the control line, a semi-circular steel pipe protective cover is installed close to the side wall of the lower chamber and fixed to the side wall of the lower chamber through temporary fixing measures. The diameter of the steel pipe protective cover is greater than the thickness of the anti-seepage wall; In the foundation pit of the lower lock chamber on the side of the isolation dam, rubble is backfilled in layers by rolling to the top elevation of the underwater dump dam body. The steel pipe protective cover is fixed by rubble, and the temporary fixing measures are removed from bottom to top as the rubble backfill rises; After using temporary cofferdam II to block the upstream and downstream of the control section in the flood discharge gate flow channel on the opposite bank, temporary cofferdam I was dismantled; According to the designed dimensions of the dam body and the material requirements of each area, the underwater filling is carried out from both banks to the middle or from one bank to the other bank using the advance method to form the underwater filling dam body; After the underwater dumping and filling dam body construction is completed, the slag dumping area and fine stone mixed dumping area of ​​the underwater dumping and filling dam body are reinforced by dynamic compaction method; Construct the slots for the cut-off wall and cast the cut-off wall. After the slots on the outer side of the semicircular steel pipe protective cover are formed, the solid wall slurry used in the cut-off wall construction is used to replace the accumulated water in the semicircular steel pipe protective cover. The semicircular steel pipe protective cover is then lifted using a lifting device. The solid wall slurry in the protective cover protects the expanded end of the cut-off wall and stabilizes the slots, allowing the slots in the cut-off wall to extend to the side wall of the lower gate chamber. After the cut-off wall is formed, the dam foundation curtain grouting construction is carried out from the top of the cut-off wall; The dam body is constructed by rolling on water. After the construction of the cut-off wall is completed, the construction platform on the top of the cut-off wall is removed, the mud-containing concrete on the top of the cut-off wall is chiseled out, the steel mesh of the upper cast-in-place concrete core wall is tied and overlapped with the steel mesh of the cut-off wall, and the cast-in-place concrete core wall is cast in the formwork; After the cast-in-place concrete core wall is constructed to the dam crest elevation, multiple seam holes are drilled from the dam crest downwards, corresponding to the gap between the enlarged end of the cut-off wall and the lower gate chamber. Water-soluble polyurethane is poured into the seam holes to form water stoppers. Continue pouring the upper wave-breaking wall portion of the cast-in-place concrete core wall; Carry out foundation consolidation grouting and curtain grouting construction of the lower chamber floor; Temporary cofferdam II will be removed after the construction of the lower lock chamber is completed.

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