Concrete construction device for foundation constraint area of gravity dam

Abstract

The utility model discloses a gravity dam foundation constraint area concrete construction device which comprises a peripheral steel formwork used for limiting the boundary of the appearance of a gravity dam, anti-crack formworks longitudinally and transversely spliced in the peripheral steel formwork to form a grid shape, and cooling water pipes spirally arranged in the internal area of the grid. The anti-crack formwork is of a rectangular cylindrical structure prefabricated by concrete, a primary pouring area is formed in a grid inner area, the primary pouring area is filled with pre-poured concrete pouring blocks, a secondary pouring area is formed by a cavity of the anti-crack formwork, and the secondary pouring area is filled with post-poured concrete pouring blocks. The gravity dam is divided into the primary pouring area and the secondary pouring area, shrinkage stress generated when the concrete pouring blocks in the primary pouring area are cooled is released in a cracking mode of the anti-cracking formwork, and the risk that temperature cracks are generated in concrete in the foundation constraint area of the gravity dam is effectively reduced; meanwhile, the purposes of reducing the construction cost and shortening the construction period are achieved; and the anti-crack template is prefabricated by concrete and does not need to be dismounted.

Description

Technical Field

[0001] The utility model relates to a construction device, in particular to a concrete construction device for a gravity dam foundation constraint zone. Background Art

[0002] Gravity dams are large-volume water-retaining structures built with concrete or mortar masonry. They belong to large-volume concrete projects. Due to the hydration heat of cement, the internal temperature of concrete will rise sharply after pouring. Later, the concrete will cool down and shrink. Under the condition of foundation constraints, it will often produce considerable tensile stress, causing cracks in the dam concrete. To avoid this situation, construction is usually carried out in low-temperature seasons, but due to factors such as construction schedules, it is often unavoidable to carry out construction in high-temperature seasons or high-temperature environments. At this time, due to the superposition of cement hydration heat and ambient temperature, the maximum temperature in the concrete is higher, and the concrete will cool down more in the later period, which is more likely to cause large-scale serious cracks.

[0003] Most existing technologies use the following methods to prevent cracks in gravity dams: using equipment in the refrigeration industry to cool mixing water to reduce the temperature of concrete out of the machine; adding hydration heat inhibitors to reduce the release of hydration heat of concrete; precooling aggregates to reduce the pouring temperature, etc. However, in actual construction, the above construction crack prevention solutions are costly, have a long cooling time, and a long construction period. Utility Model Content

[0004] Purpose of the utility model: The purpose of the utility model is to provide a concrete construction device for the constraint zone of the foundation of a gravity dam, which can reduce the probability of temperature cracks in the gravity dam and shorten the construction period.

[0005] Technical solution: The utility model discloses a gravity dam foundation constraint zone concrete construction device, comprising an outer steel formwork for defining the outer boundary of the gravity dam, an anti-crack formwork longitudinally and transversely spliced ​​inside the outer steel formwork to form a grid, and a cooling water pipe spirally arranged in the inner area of ​​the grid, wherein the anti-crack formwork is a rectangular cylindrical structure prefabricated with concrete, wherein the inner area of ​​the grid constitutes a primary casting area, which is filled with first-cast concrete blocks, and the cavity of the anti-crack formwork constitutes a secondary casting area, which is filled with post-cast concrete blocks.

[0006] Furthermore, the cooling water pipe is pre-buried in each pre-cast concrete casting block, and the cooling water pipes in each pre-cast concrete casting block are independent of each other.

[0007] Furthermore, the cooling water pipe is spirally arranged in the primary casting area, the water inlet of the cooling water pipe is located at the center of the primary casting area, and the water outlet of the cooling water pipe is located at the edge of the primary casting area.

[0008] Furthermore, the length and width of the primary casting area are both 8 to 10 meters.

[0009] Furthermore, the width of the anti-cracking template is 0.5 to 0.6 meters.

[0010] Furthermore, the wall thickness of the anti-cracking template is 0.1 to 0.15 meters.

[0011] Furthermore, a middle partition wall is provided in the cavity of the anti-crack formwork along the width direction, and the middle partition wall and the anti-crack formwork are integrally cast by concrete.

[0012] Furthermore, a hoisting hole is provided at the upper end of the middle partition wall.

[0013] Furthermore, the outer surface of the anti-crack template is provided with a plurality of key grooves for increasing the bonding force.

[0014] Furthermore, the upper ends of the side walls at both ends of the anti-cracking template are provided with hanging holes.

[0015] Beneficial effects: Compared with the prior art, the utility model has the following advantages: the utility model divides the gravity dam into a primary pouring area and a secondary pouring area, so that after the primary pouring area is poured, the prefabricated concrete anti-cracking formwork will replace the concrete cracking of the first pouring in the form of cracking. Because the anti-cracking formwork is the lateral constraint of the concrete in the primary pouring area of ​​the first pouring, and the wall thickness is less than the width and length of the primary pouring area, its crack resistance is much smaller than the crack resistance of the concrete casting block in the primary pouring area. Therefore, under the influence of shrinkage stress, it will help the concrete casting block in the primary pouring area release shrinkage stress in the form of cracking; pouring micro-expansion concrete in the secondary pouring area for the second time can ensure the integrity of the gravity dam structure;

[0016] The anti-crack formwork is prefabricated with concrete and does not need to be dismantled. It has a simple structure and can be prefabricated in batches for rapid construction. The anti-crack formwork is prefabricated with concrete and can be used as part of the complete structure of the gravity dam. During the first and second pouring periods, there is no need to manually dismantle the anti-crack formwork. After all pouring is completed, only the outer steel formwork needs to be dismantled, which can simplify the construction steps and shorten the construction period. The anti-crack formwork has a relatively simple structure and a unified form and can be prefabricated in batches, which reduces the difficulty of prefabrication of the anti-crack formwork. The formwork is provided with hoisting holes, which can be quickly hoisted at the construction site.

[0017] The key groove provided on the outside of the anti-crack formwork can enhance the shear resistance of the anti-crack formwork and the concrete joint surface in the primary pouring area, and enhance the bonding effect between the concrete in the primary pouring area and the anti-crack formwork concrete;

[0018] The anti-crack formwork increases the heat dissipation area of ​​the concrete in the primary pouring area, lowers the maximum temperature of the concrete in the primary pouring area, and reduces the temperature stress of the concrete temperature drop in the later primary pouring area; at the same time, according to the differences in temperature control requirements of various parts of the concrete in the primary pouring area, the cooling water pipes are arranged in a spiral shape, with the water inlet arranged in the center of the primary pouring area and the water outlet arranged at the edge of the primary pouring area, thereby enhancing the temperature control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a top view of the utility model;

[0020] Figure 2 It is a structural schematic diagram of the anti-crack template of the utility model;

[0021] Figure 3 It is a top view of the anti-crack template of the utility model;

[0022] Figure 4 It is a top view of the cooling water pipe of the utility model. DETAILED DESCRIPTION

[0023] The technical solution of the utility model is further described below in conjunction with the accompanying drawings.

[0024] like Figures 1 to 4 As shown, a concrete construction device for a gravity dam foundation constraint zone of the utility model comprises an anti-crack formwork 1, a cooling water pipe 2 and an outer steel formwork 3. The outer steel formwork 3 is used to realize the enclosure and fixation of the outer boundary of the foundation concrete pouring area. The anti-crack formwork 1 is provided with a plurality of anti-crack formworks. The specific data of the anti-crack formwork 1 is determined according to the actual construction situation. The plurality of anti-crack formworks 1 are spliced ​​vertically and horizontally in the outer steel formwork 3, and the anti-crack formwork 1 and the outer steel formwork 3 form a grid shape, and the internal area of ​​the grid constitutes a primary pouring area 4 for the first pouring. The primary pouring area 4 is filled with a first pouring concrete pouring block. The anti-crack formwork 1 is a rectangular cylindrical structure, and the anti-crack formwork 1 has a plurality of The cavity constitutes the secondary pouring area 5 for the second pouring, and the secondary pouring area 5 is filled with post-poured concrete blocks; wherein the anti-crack formwork 1 is made of concrete pouring, and there is no need to remove the anti-crack formwork 1 during the later pouring. Preferably, the anti-crack formwork 1 is made of C30 concrete, has a certain dead weight, and has a higher strength than the strength of the C25 concrete of the gravity dam body (the first cast concrete blocks filled in the primary pouring area 4). The anti-crack formwork 1 can be used as a support constraint when pouring concrete in the primary pouring area 4 of the gravity dam to resist the thrust of the flowing concrete during pouring. At the same time, the post-poured concrete blocks filled in the secondary pouring area 5 serve as part of the overall structure of the gravity dam.

[0025] Specifically, cooling water pipes 2 are pre-buried in the first-cast concrete blocks of the primary casting area 4. The cooling water pipes 2 are used to cool the internal temperature of the first-cast concrete blocks in the primary casting area 4. The multiple cooling water pipes 2 are independent of each other, which is convenient for independently controlling the temperature of different primary casting areas 4; the cooling water pipes 2 are spiral-shaped, and the water inlet 9 of the cooling water pipes 2 is located at the center of the primary casting area 4, and the water outlet 10 of the cooling water pipes 2 is located at the edge of the primary casting area 4. When cooling with water, the cooling water will absorb the hydration heat of the first-cast concrete blocks in the primary casting area 4, and its temperature will gradually increase along the direction of the water flow path. Therefore, according to the primary casting area 4, the water temperature at the water inlet 9 is the lowest, which is set at the center of the primary casting area 4 to prevent the temperature concentration phenomenon caused by poor heat dissipation capacity in the center. The water temperature at the water outlet is the highest, which is set at the edge of the primary casting area 4. The concrete hydration heat dissipation at the edge of the primary casting area 4 is better, and the cooling requirement for the water pipe is relatively low. The cooling water pipe 2 is arranged in a spiral shape in the primary casting area 4, and the cooling effect gradually decreases from the center of the casting block to the edge, which adapts to the heat dissipation capacity of the concrete in each part; the water inlet 9 and the water outlet 10 of the cooling water pipe 2 between each primary casting area 4 are not connected in series, and the inlet and outlet water are each controlled by a specific separate water supply system.

[0026] Specifically, the length and width of the primary pouring area 4 are both 8 to 10 meters. The wall thickness of the anti-crack formwork 1 is 0.1 to 0.15 meters. The width of the anti-crack formwork 1 is 0.5 to 0.6 meters. Preferably, in this embodiment, the anti-crack formwork 1 is prefabricated with C30 concrete, and the anti-crack formwork 1 is 1.5 meters long, 0.5 meters wide, 1.5 meters high, and 0.1 meters thick.

[0027] During pouring, concrete is first poured into the primary pouring area 4, and then the concrete in the primary pouring area 4 is cooled by the cooling water pipe 2, and finally concrete is poured into the secondary pouring area 5, and the concrete poured into the secondary pouring area 5 is preferably micro-expansion concrete, which means that a certain expansion agent is added to ordinary concrete, so that the concrete can expand to a certain extent during the hydration period by relying on the action of the expansion agent, thereby compensating for the shrinkage of the concrete, achieving the purpose of preventing and controlling concrete cracks and improving concrete performance; in order to prevent the gravity dam concrete from generating shrinkage stress during the cooling stage and causing the gravity dam concrete to crack, after pouring into the primary pouring area 4 , the concrete in the primary pouring area 4 is cooled by water pipes in advance. Since the length and width of the primary pouring area 4 are both 8 to 10 meters, the width of the anti-crack formwork 1 is 0.5 to 0.6 meters, and the wall thickness of the anti-crack formwork 1 is 0.1 to 0.15 meters, the anti-crack ability of the anti-crack formwork 1 is much smaller than the first-cast concrete blocks in the primary pouring area 4. Therefore, under the influence of the concrete temperature stress in the primary pouring area 4, the anti-crack formwork 1 will crack before the first-cast concrete blocks in the primary pouring area 4, and release its shrinkage stress, remove harmful constraints, and pour micro-expansion concrete into the secondary pouring area 5, which is helpful to fully fill the cracks and ensure the integrity and safety of the structure. Under the premise of ensuring that the final structural integrity of the gravity dam is not affected, this embodiment releases the shrinkage stress generated when the gravity dam concrete is cooled in the form of cracking the anti-crack formwork 1, effectively reducing the risk of temperature cracks in the concrete in the constraint area of ​​the gravity dam foundation, while achieving the purpose of reducing construction costs and shortening the construction period.

[0028] Specifically, after the concrete casting blocks in the secondary casting area 5 are cast, the anti-crack formwork 1 does not need to be dismantled because it is prefabricated with concrete. The anti-crack formwork 1 has a simple structure and can be prefabricated in batches and constructed quickly. It can be used as a part of the complete structure of the gravity dam. During the first and second castings, there is no need to manually dismantle the anti-crack formwork 1. After all the casting is completed, only the outer steel formwork 3 needs to be dismantled, which can simplify the construction steps. At the same time, the anti-crack formwork 1 has a simple structure and a unified form and can be prefabricated in batches, which reduces the difficulty of prefabrication of the anti-crack formwork 1.

[0029] Specifically, a middle partition wall 6 is provided in the cavity of the anti-crack formwork 1 along the width direction. The middle partition wall 6 and the anti-crack formwork 1 are integrally cast by concrete. The middle partition wall 6 divides the cavity of the anti-crack formwork 1 into two cavities of equal volume, which is beneficial to enhancing the structural stability of the anti-crack formwork 1.

[0030] Specifically, the outer surface of the anti-crack formwork 1 is provided with a plurality of key grooves 8, which are beneficial to enhancing the shear resistance of the anti-crack formwork 1 and the concrete joint surface in the primary pouring area 4, and enhancing the bonding force between the anti-crack formwork 1 and the concrete joint surface in the primary pouring area 4 after pouring is completed.

[0031] Specifically, the upper ends of the two side walls of the anti-crack formwork 1 are provided with lifting holes 7, and the upper end of the middle partition wall 6 is also provided with a lifting hole 7. The setting of the lifting holes 7 facilitates the lifting of the anti-crack formwork 1 by the crane hook, and facilitates the subsequent transportation and assembly of the anti-crack formwork 1.

[0032] Workflow: transport the anti-crack formwork 1, cooling water pipe 2 and outer steel formwork 3 to the construction site, fix the outer steel formwork 3 at the corresponding construction position, and fit the anti-crack formwork 1 into the outer steel formwork 3 through the lifting equipment. When splicing the anti-crack formwork 1, the anti-crack formwork 1 should be fit together as much as possible to prevent the flow concrete from overflowing when pouring concrete in the subsequent primary pouring area 4. If a large gap cannot be avoided between the two anti-crack formworks 1 due to the actual situation at the construction site, part of the concrete can be filled to bridge the gap, and the cooling water pipe 2 can be pre-buried in the primary pouring area 4; then pour concrete into the primary pouring area 4, and then cool the concrete in the primary pouring area 4 through the cooling water pipe 2. Under the influence of the temperature stress of the concrete in the primary pouring area 4, the anti-crack formwork 1 will crack before the concrete pouring block in the primary pouring area 4, and release its shrinkage stress, remove harmful constraints, and then pour micro-expansion concrete into the secondary pouring area 5. At the same time, the poured micro-expansion concrete will fully fill the cracks formed by the cracking of the anti-crack formwork 1 to ensure the integrity and safety of the structure.

Claims

1. A gravity dam foundation restraint zone concrete construction device, characterized in that: The invention comprises an outer steel formwork (3) for defining the outer boundary of a gravity dam, an anti-crack formwork (1) longitudinally and transversely spliced ​​inside the outer steel formwork (3) to form a grid, and a cooling water pipe (2) spirally arranged in the inner area of ​​the grid, wherein the anti-crack formwork (1) is a rectangular cylindrical structure prefabricated from concrete, wherein the inner area of ​​the grid constitutes a primary pouring area (4), the primary pouring area (4) is filled with first-poured concrete blocks, and the cavity of the anti-crack formwork (1) constitutes a secondary pouring area (5), the secondary pouring area (5) is filled with post-poured concrete blocks.

2. The gravity dam foundation restraint zone concrete construction device according to claim 1, characterized in that: The cooling water pipe (2) is pre-buried in each pre-cast concrete casting block, and the cooling water pipes (2) in each pre-cast concrete casting block are independent of each other.

3. The gravity dam foundation restraint zone concrete construction device according to claim 2, characterized in that: The water inlet (9) of the cooling water pipe (2) is located at the center of the primary casting area (4), and the water outlet (10) of the cooling water pipe (2) is located at the edge of the primary casting area (4).

4. The gravity dam foundation restraint zone concrete construction device according to claim 1, characterized in that: The length and width of the primary pouring area (4) are both 8 to 10 meters.

5. The gravity dam foundation restraint zone concrete construction device according to claim 1, characterized in that: The width of the anti-cracking template (1) is 0.5 to 0.6 meters.

6. The gravity dam foundation restraint zone concrete construction device according to claim 1, characterized in that: The wall thickness of the anti-cracking template (1) is 0.1 to 0.15 meters.

7. The gravity dam foundation restraint zone concrete construction device according to claim 1, characterized in that: A middle partition wall (6) is provided in the cavity of the anti-crack formwork (1) along the width direction, and the middle partition wall (6) and the anti-crack formwork (1) are integrally cast by concrete.

8. The gravity dam foundation restraint zone concrete construction device according to claim 7, characterized in that: A hoisting hole (7) is provided at the upper end of the middle partition wall (6).

9. The gravity dam foundation restraint zone concrete construction device according to claim 1, characterized in that: The outer surface of the anti-crack template (1) is provided with a plurality of key grooves (8) for increasing the bonding force.

10. The gravity dam foundation restraint zone concrete construction device according to claim 1, characterized in that: The upper ends of the side walls at both ends of the anti-cracking template (1) are provided with hanging holes (7).

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