Joint structure of concrete diaphragm wall and core wall base and construction method of joint structure

Abstract

The invention relates to the technical field of asphalt concrete core wall rock-fill dam construction, in particular to a joint structure of a concrete diaphragm wall and a core wall base and a construction method of the joint structure. The joint structure comprises an anti-seepage wall assembly, a first core wall base and a second core wall base, the bottom of the anti-seepage wall assembly is poured on bedrock, the first core wall base is arranged at the turning position of a bank slope base and a riverbed base and poured on the bedrock, the end of the anti-seepage wall assembly extends into the first core wall base, and the second core wall base is arranged at the top of the anti-seepage wall assembly; a first contact surface, a second contact surface and a third contact surface are arranged between the diaphragm wall assembly and the first core wall base, the first contact surface, the second contact surface and the third contact surface respectively correspond to three adjacent side walls of the diaphragm wall assembly, and protective layers are arranged in the first contact surface, the second contact surface and the third contact surface; a water stop assembly is arranged at the joint of the second core wall base and the anti-seepage wall assembly; the anti-seepage performance of the asphalt concrete core wall rock-fill dam is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt concrete core wall rockfill dam construction, and particularly relates to a joint structure between a concrete cut-off wall and a core wall foundation and a construction method thereof. Background Art

[0002] An asphalt concrete core wall rockfill dam is a type of dam widely used in water conservancy and hydropower projects. When an asphalt concrete core wall rockfill dam is built on a deep overburden layer, in order to meet the anti-seepage requirements of the dam foundation, a concrete cut-off wall is usually set in the dam foundation overburden layer to reach the bedrock. In the past, the joint treatment technology between the concrete cut-off wall and other anti-seepage structures was relatively simple. The commonly used methods were direct connection type or keyway type, which had disadvantages such as poor bonding reliability, poor deformation adaptability, and unstable anti-seepage performance, and often could not meet complex projects, especially the anti-seepage requirements of pumped storage power stations with relatively high anti-seepage requirements. If the joint between the concrete cut-off wall and other anti-seepage structures is not properly treated and cannot be completely sealed, over time and with the change of water level, water gradually seeps into the dam body from the joint part, which not only causes the rise of the dam body phreatic line, but also makes the soil materials inside the dam body in a saturated state for a long time, reducing the strength and stability of the soil materials, resulting in local deformation and settlement of the dam body. If not treated in time, it may lead to more serious safety accidents such as dam body landslides.

[0003] The prior art CN115992501B discloses an asphalt concrete core wall dam and a construction method. The asphalt concrete core wall dam includes a concrete foundation, an asphalt concrete core wall, an asphalt mortar anti-seepage and sealing frame, and a clay covering belt. The asphalt concrete core wall is arranged on the concrete foundation, the asphalt mortar anti-seepage and sealing frame covers the construction joint on the upstream side of the concrete foundation, and the clay covering belt covers the upstream side of the concrete foundation and part of the upstream side of the asphalt concrete core wall. Through the asphalt mortar anti-seepage and sealing frame and the clay covering belt, the lower structure of the asphalt concrete core wall is anti-seeped and reinforced, with simple structure, convenient construction, and good anti-seepage and reinforcement effects. However, when the asphalt concrete core wall dam is located in a place with poor environment and the overburden layer on the bedrock of the bank connected to the dam shoulder is thick, at this time, using the anti-seepage structure of the above asphalt concrete core wall dam, the anti-seepage effect at the connection between the dam shoulder and the bank is poor.

[0004] Therefore, there is an urgent need to provide a joint structure between a concrete cut-off wall and a core wall foundation and a construction method thereof, which can enhance the reliability of the connection between the dam shoulder and the bank bedrock and improve the anti-seepage performance of the core wall dam compared with the prior art. Summary of the Invention

[0005] The present invention solves the technical problems existing in the prior art, and provides a joint structure between a concrete cut-off wall and a core wall foundation and a construction method thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: A joint structure between a concrete cut-off wall and a core wall foundation includes a cut-off wall assembly, a first core wall foundation, and a second core wall foundation. The bottom of the cut-off wall assembly is cast on the bedrock. The first core wall foundation is arranged at the turning part of the bank slope foundation and the riverbed foundation, and the first core wall foundation is also cast on the bedrock. The second core wall foundation is arranged on the top of the cut-off wall assembly. There are a first contact surface, a second contact surface, and a third contact surface between the cut-off wall assembly and the first core wall foundation. The first contact surface, the second contact surface, and the third contact surface respectively correspond to three adjacent side walls of the cut-off wall assembly, and protective layers are provided in the first contact surface, the second contact surface, and the third contact surface. A water stop assembly is provided between the second core wall foundation and the cut-off wall assembly.

[0007] Further, the cut-off wall assembly includes a first concrete cut-off wall and a second concrete cut-off wall. The first concrete cut-off wall and the second concrete cut-off wall are cast and fixed, and the connection part between the first concrete cut-off wall and the second concrete cut-off wall is located within the first core wall foundation.

[0008] Furthermore, an arc-shaped construction joint is provided between the first concrete cut-off wall and the second concrete cut-off wall, and a waterproof layer is provided in the construction joint. The waterproof layer includes an acrylic emulsion liquid layer and an acrylic emulsion mortar layer.

[0009] Furthermore, water stop belts are provided at the upstream end and the downstream end of the construction joint. The water stop belts include rubber plates and cover plates, and GB flexible filler is also used to fill the gaps generated therein.

[0010] Furthermore, a plurality of inserted bars are buried between the first concrete cut-off wall and the second concrete cut-off wall, and the ratio of the length of the inserted bars extending into the first concrete cut-off wall to the length of the inserted bars extending into the second concrete cut-off wall is 17:3.

[0011] Furthermore, a U-shaped copper water stop is buried between the second concrete cut-off wall and the first core wall foundation. The upper end of the U-shaped copper water stop is connected to a copper water stop joint, and both ends of the copper water stop joint are also connected to Z-shaped copper water stops, and the Z-shaped copper water stops are buried in the asphalt concrete core wall.

[0012] Further, the water stop assembly includes a water stop groove and a water stop strip. The water stop groove is chiseled on the top of the cut-off wall assembly, and the water stop strip is arranged in the water stop groove and is used for swelling when encountering water.

[0013] Further, the protective layer includes an emulsified asphalt layer and an asphalt mortar layer.

[0014] Furthermore, an arc-shaped groove is provided at the top of the second core wall base, and the asphalt concrete core wall is poured into the arc-shaped groove.

[0015] A construction method for the joint structure between a concrete cut-off wall and a core wall base includes the following steps: S1. Pour the first concrete cut-off wall, chisel off the top and both ends of the first concrete cut-off wall, and embed insertion bars in the first concrete cut-off wall before pouring the second concrete cut-off wall. S2. Set a construction joint on the end face of the first concrete cut-off wall, construct a waterproof layer therein, then pour the second concrete cut-off wall, and embed a U-shaped copper waterstop during the pouring of the second concrete cut-off wall. S3. Chisel a waterstop groove on the top of the cut-off wall assembly and place a waterstop strip in the waterstop groove. S4. After chiseling and washing the top of the cut-off wall assembly until it is clean, pour the second core wall base. S5. Construct waterstops at both the upstream end and the downstream end of the construction joint, and then construct protective layers at the positions of the first contact surface, the second contact surface, and the second and third contact surfaces. S6. Pour the first core wall base, reserve a groove on the first core wall base, and then connect the integrally poured cut-off wall assembly and the second core wall base in the groove. S7. Pour and connect the asphalt concrete core wall through the U-shaped copper waterstop, Z-shaped copper waterstop, and copper waterstop joint.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The cut-off wall assembly, the first core wall base, and the second core wall base provided in the present invention are arranged at the turning point between the bank slope dam section and the riverbed dam section. For a core wall dam with poor foundation conditions, using the present invention to connect the bank slope dam section founded on bedrock and the riverbed dam section founded on overburden, on the basis of the structure of the traditional core wall dam anti-seepage system, adding the structure of the present invention can achieve a better anti-seepage effect and enhance the stable connection between the bank slope dam section and the riverbed dam section. On the basis of fully considering the integrity of the anti-seepage system and the stability of the structure, a joint structure that is simple in construction, reasonable in economy, safe and effective is provided. The present invention can be well applied to the asphalt concrete core wall rockfill dam on deep overburden, ensuring the reliability of the joint between the concrete cut-off wall and the asphalt concrete core wall base, and improving the anti-seepage performance of the asphalt concrete core wall rockfill dam. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic top view of the joint structure of the present invention.

[0018] Figure 2 is Figure 1 the sectional view taken along the line A-A in

[0019] Figure 3 is Figure 1 the sectional view taken along line B-B in the middle.

[0020] Figure 4 is a schematic diagram showing the connection relationship between the first concrete cut-off wall and the second concrete cut-off wall in the present invention.

[0021] Description of reference numerals: 1. First concrete cut-off wall; 2. Second concrete cut-off wall; 3. First core wall foundation; 4. Second core wall foundation; 5. Copper waterstop assembly; 51. U-shaped copper waterstop; 52. Z-shaped copper waterstop; 6. Anchor bars; 7. Construction joint; 8. Asphalt concrete core wall; 9. Waterstop strip; 10. First contact surface; 11. Second contact surface; 12. Third contact surface; 13. Waterstop groove; 14. Waterstop belt. Specific embodiments

[0022] The technical solutions of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. It should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0023] As Figure 1 、 Figure 2 shown, the present invention provides a joint structure between a concrete cut-off wall and a core wall foundation, including a cut-off wall assembly, a first core wall foundation 3 and a second core wall foundation 4. The cut-off wall assembly is poured on the bedrock, the first core wall foundation 3 is poured on the bedrock at the turning part of the bank slope foundation and the riverbed foundation. One end of the cut-off wall assembly extends into the first core wall foundation 3, the upper end of the cut-off wall assembly is poured with the second core wall foundation 4, the second core wall foundation 4 is fixedly connected to the first core wall foundation 3 by pouring, the upper end of the second core wall foundation 4 is poured with an asphalt concrete core wall 8, and a waterstop assembly is provided between the second core wall foundation 4 and the cut-off wall assembly.

[0024] As Figure 1 、 Figure 4The side wall of the shown first core wall base 3 is provided with a groove. The anti-seepage wall assembly includes a first concrete anti-seepage wall 1 and a second concrete anti-seepage wall 2. The second concrete anti-seepage wall 2 is arranged in the groove. The side wall of the second concrete anti-seepage wall 2 away from the first core wall base 3 is an inwardly concave arc surface. The first concrete anti-seepage wall 1 is cast on the arc surface side of the second concrete anti-seepage wall 2. Part of the first concrete anti-seepage wall 1 is arranged in the groove, and the first concrete anti-seepage wall 1 extends out of the groove; the first concrete anti-seepage wall 1 and the second concrete anti-seepage wall 2 are connected by multiple dowel bars 6. The ratio of the length of each dowel bar 6 extending into the first concrete anti-seepage wall 1 to the length extending into the second concrete anti-seepage wall 2 is 17:3. That is, when the length of the dowel bar 6 is 2m, the length extending into the first concrete anti-seepage wall 1 is 1.7m, and the length extending into the second concrete anti-seepage wall 2 is 0.3m, arranged in a plum blossom shape of 20*20cm; a copper water stop assembly 5 is arranged between the second concrete anti-seepage wall 2 and the first core wall base 3.

[0025] A construction joint 7 is provided between the first concrete anti-seepage wall 1 and the second concrete anti-seepage wall 2. The construction joint 7 is arc-shaped and has an upstream end and a downstream end; there is an anti-seepage layer in the construction joint 7. The anti-seepage layer includes a acrylic emulsion base liquid layer and an acrylic emulsion mortar layer. The acrylic emulsion base liquid layer is coated on the side wall of the first concrete anti-seepage wall 1, and the acrylic emulsion mortar layer is laid on the acrylic emulsion base liquid layer. The thickness of the acrylic emulsion base liquid layer is preferably 1-2mm, and the thickness of the acrylic emulsion mortar layer is preferably 1-2cm; water stop belts 14 are provided at both the upstream end and the downstream end of the construction joint 7. The water stop belts 14 cover the upstream end and the downstream end of the construction joint 7. The water stop belts 14 include rubber plates and cover plates. The rubber plates are made of ethylene propylene diene monomer rubber plates. The thickness ratio of the rubber plates to the cover plates is 8:5. The thickness of the rubber plates is preferably 8mm, and the thickness of the cover plates is preferably 5mm. The water stop belts 14 also use GB flexible filler to fill the gaps.

[0026] A first contact surface 10 is also provided on the upstream side surfaces of the first concrete anti-seepage wall 1 and the second concrete anti-seepage wall 2. The first contact surface 10 covers the water stop belt 14 provided at the upstream end of the construction joint 7; a second contact surface 11 is also provided on the downstream side surfaces of the first concrete anti-seepage wall 1 and the second concrete anti-seepage wall 2. The second contact surface 11 covers the water stop belt 14 provided at the downstream end of the construction joint 7; a third contact surface 12 is provided between the side wall of the second concrete anti-seepage wall 2 away from its arc surface and the first core wall base 3; protective layers are provided in the first contact surface 10, the second contact surface 11, and the third contact surface 12. Each protective layer includes an emulsified asphalt layer and an asphalt mortar layer. The emulsified asphalt layer is formed by spraying cationic emulsified asphalt on the side walls of the first concrete anti-seepage wall 1, the second concrete anti-seepage wall 2, the side wall of the first upstream construction joint 8, and the side wall of the first downstream construction joint 9. After the emulsified asphalt layer dries, an asphalt mortar layer is painted on the outer surface of the emulsified asphalt layer. The spraying volume of the cationic emulsified asphalt is preferably 0.2kg / m², and the thickness of the asphalt mortar layer is preferably 2cm.

[0027] As shown Figure 1 、 Figure 2 in the figure, the water stop assembly includes a water stop groove 13 and a water stop strip 9. The water stop groove 13 is arranged at the top of the impervious wall assembly, and the water stop strip 9 is placed in the water stop groove 13. The water stop strip 9 expands when encountering water and fills the water stop groove 13, thereby playing a role in preventing seepage. The upper end surface of the second core wall base 4 is provided with an arc-shaped groove, and the asphalt concrete core wall 8 is poured in the arc-shaped groove.

[0028] As shown Figure 3 in the figure, the copper water stop assembly 5 includes a U-shaped copper water stop 51 and a Z-shaped copper water stop 52. The second concrete impervious wall 2 is poured and connected with the first core wall base 3 through the U-shaped copper water stop 51. The U-shaped copper water stop 51 is connected to the copper water stop joint, and the copper water stop joint is a special-shaped copper water stop joint. A plurality of Z-shaped copper water stops 52 are further arranged at both ends of the copper water stop joint, and the Z-shaped copper water stop 52 is poured and connected with the asphalt concrete core wall 8.

[0029] The present invention also provides a construction method for the joint structure of the concrete impervious wall and the core wall base, including the following steps: S1. Pour the first concrete impervious wall 1, chisel off the first concrete impervious wall 1 with poor construction quality at the top and both ends, and embed the inserted steel bars 6 in the first concrete impervious wall 1 before pouring the second concrete impervious wall 2.

[0030] S2. Set a construction joint 7 on the end face of the first concrete impervious wall 1, and construct and set an anti-seepage layer therein, and then pour the second concrete impervious wall 2 so that the second concrete impervious wall 2 is poured on the outer side wall of the anti-seepage layer. When pouring the second concrete impervious wall 2, embed the U-shaped copper water stop 51.

[0031] S3. Chisel a water stop groove 13 at the top of the impervious wall assembly, and place the water stop strip 9 in the water stop groove 13.

[0032] S4. After chiseling and washing the top of the impervious wall assembly until it is clean, pour the second core wall base 4.

[0033] S5. Construct and set water stop belts at the positions of the first upstream construction joint 8 and the first contact surface 10, and then construct and set protective layers at the positions of the first contact surface 10, the second contact surface 11, and the third contact surface 12.

[0034] S6. Pour the first core wall base 3, and reserve a groove on the first core wall base 3, and then connect the integrally poured impervious wall assembly and the second core wall base 4 in the groove through the copper water stop assembly 5.

[0035] S7. Through the U-shaped copper water stop 51, the Z-shaped copper water stop 52 and the copper water stop joint, pour and connect the asphalt concrete core wall 8, and at the same time spray emulsified asphalt and asphalt mortar.

[0036] The impervious wall assembly, the first core wall foundation 3 and the second core wall foundation 4 provided by the present invention are arranged at the turning point between the bank slope dam section and the riverbed dam section. For a core wall dam with poor foundation conditions, the present invention is used to connect the bank slope dam section founded on bedrock and the riverbed dam section founded on overburden. On the basis of the structure of the traditional core wall dam impervious system, adding the structure of the present invention can achieve a better impervious effect and enhance the stable connection between the bank slope dam section and the riverbed dam section. On the basis of fully considering the integrity of the impervious system and the stability of the structure, a joint structure that is simple in construction, reasonable in economy, safe and effective is provided. The present invention can be well applied to the asphalt concrete core wall rockfill dam on deep overburden, ensuring the reliability of the joint between the concrete impervious wall and the asphalt concrete core wall foundation, and improving the impervious performance of the asphalt concrete core wall rockfill dam.

[0037] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than limiting the protection scope of the present invention. Any simple modification or equivalent replacement made by those of ordinary skill in the art to the technical solution of the present invention shall not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A joint structure between a concrete cut-off wall and a core wall foundation, characterized in that It includes a cut-off wall assembly, a first core wall foundation and a second core wall foundation. The bottom of the cut-off wall assembly is cast on the bedrock. The first core wall foundation is arranged at the turning part of the bank slope foundation and the river bed foundation, and the first core wall foundation is also cast on the bedrock. The second core wall foundation is arranged on the top of the cut-off wall assembly. There are a first contact surface, a second contact surface and a third contact surface between the cut-off wall assembly and the first core wall foundation. The first contact surface, the second contact surface and the third contact surface respectively correspond to three adjacent side walls of the cut-off wall assembly, and protective layers are provided in the first contact surface, the second contact surface and the third contact surface. A water stop assembly is provided between the second core wall foundation and the cut-off wall assembly.

2. The joint structure of a concrete cut-off wall and a core wall foundation according to claim 1, characterized in that, The cut-off wall assembly includes a first concrete cut-off wall and a second concrete cut-off wall. The first concrete cut-off wall and the second concrete cut-off wall are cast and fixed, and the connection part of the first concrete cut-off wall and the second concrete cut-off wall is located in the first core wall foundation.

3. The joint structure between a concrete cut-off wall and a core wall foundation according to claim 2, characterized in that An arc-shaped construction joint is provided between the first concrete cut-off wall and the second concrete cut-off wall, and a waterproof layer is provided in the construction joint. The waterproof layer includes an acrylic emulsion base liquid layer and an acrylic emulsion mortar layer.

4. The joint structure between a concrete cut-off wall and a core wall foundation according to claim 2, wherein, Water stop belts are provided at the upstream end and the downstream end of the construction joint. The water stop belt includes a rubber plate and a cover plate, and the GB flexible filler is also used to fill the gaps generated therein.

5. The joint structure of a concrete cut-off wall and a core wall foundation according to claim 2, characterized in that, A plurality of dowel bars are buried between the first concrete cut-off wall and the second concrete cut-off wall, and the ratio of the length of the dowel bar extending into the first concrete cut-off wall to the length extending into the second concrete cut-off wall is 17:

3.

6. The joint structure of a concrete cut-off wall and a core wall foundation according to claim 2, characterized in that, A U-shaped copper water stop is buried between the second concrete cut-off wall and the first core wall foundation. The upper end of the U-shaped copper water stop is connected to a copper water stop joint, and Z-shaped copper water stops are also connected to both ends of the copper water stop joint. The Z-shaped copper water stops are buried in the asphalt concrete core wall.

7. The joint structure between a concrete cut-off wall and a core wall foundation according to claim 1, characterized in that The water stop assembly includes a water stop groove and a water stop strip. The water stop groove is chiseled on the top of the cut-off wall assembly, and the water stop strip is arranged in the water stop groove. The water stop strip is used for swelling when meeting water.

8. The joint structure between a concrete cut-off wall and a core wall foundation according to claim 1, characterized in that, The protective layer includes an emulsified asphalt layer and an asphalt mortar layer.

9. The joint structure between a concrete cut-off wall and a core wall foundation according to claim 1, characterized in that, An arc-shaped groove is provided at the top of the second core wall foundation, and the asphalt concrete core wall is cast in the arc-shaped groove.

10. A construction method for a joint structure between a concrete cut-off wall and a core wall foundation, characterized in that, Using the joint structure of a concrete cut-off wall and a core wall foundation according to any one of claims 1-9, it includes the following steps: S1. Pour the first concrete cut-off wall, chisel off the top and both ends of the first concrete cut-off wall, and embed dowel bars in the first concrete cut-off wall before pouring the second concrete cut-off wall. S2. Set a construction joint on the end face of the first concrete cut-off wall, and construct a waterproof layer therein, and then pour the second concrete cut-off wall. When pouring the second concrete cut-off wall, embed a U-shaped copper water stop. S3. Chisel a water stop groove on the top of the cut-off wall assembly, and place a water stop strip in the water stop groove. S4. After chiseling and flushing the top of the cut-off wall assembly until it is clean, pour the second core wall foundation. S5. Construct water stop belts at both the upstream end and the downstream end of the construction joint, and then construct protective layers at the positions of the first contact surface, the second contact surface and the third contact surface. S6. Pour the first core wall foundation, and reserve a groove on the first core wall foundation, then connect the integrally cast anti-seepage wall assembly and the second core wall foundation in the groove; S7. Pour and connect the asphalt concrete core wall through U-shaped copper water stops, Z-shaped copper water stops and copper water stop joints.

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