Concrete cracking prevention device for underground structure side wall

Abstract

The invention relates to the technical field of concrete pouring, and discloses a concrete cracking prevention device for an underground structure side wall, which comprises a mounting seat and a unit probe rod, the unit probe rod comprises a connecting sleeve, a transmission shaft is rotatably mounted in the connecting sleeve, and a driving motor is fixedly mounted at the top end of the connecting sleeve; a spiral blade is fixedly installed on the surface of the bottom end of the transmission shaft, and an expansion cover is fixedly installed on the surface of the connecting sleeve. In the concrete pouring process, a reasonable number of unit probe rods are selected to be inserted into the center position of the concrete side wall, a cooling medium is injected into the expansion cover, the center of the concrete is cooled, hydration heat of the center of the concrete is neutralized, the hydration peak value is delayed, and the temperature difference between the inner surface and the outer surface of the concrete wall is reduced; the concrete temperature stress concentration is reduced, the temperature cracking risk is reduced, the unit probe rods can be pulled out along with pouring work, a water pipe does not need to be embedded, and the effect of preventing concrete cracking is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of concrete pouring, and in particular to a device for preventing concrete cracking of a side wall of an underground structure. Background Art

[0002] Cracks in underground concrete walls are a common phenomenon. Although some small cracks will not cause harm to the normal use of the building structure, if these structures with small cracks are subjected to heavy loads or under the dual effects of external physical and chemical factors, it is easy to cause the steel bars in the concrete to rust. The development of the degree of corrosion will cause the strength of the reinforced concrete material and the stiffness of the components to decrease, thus affecting the normal use of the building.

[0003] In the prior art, a patent document with a publication number of CN222184188U discloses a pre-buried cooling device for preventing cracking of thick-walled concrete, comprising: a water pipe, wherein the water pipe is pre-buried in a concrete wall in a spiral shape, both ends of the water pipe are located on the outside of the concrete wall, support components are arranged on the left and right sides of the lower end of the water pipe, and hanging components are arranged on the left and right sides of the upper end of the water pipe; a cooling component is detachably installed on the outer wall of the water pipe, and the cooling component comprises an arc-shaped heat conducting plate 1 and an arc-shaped heat conducting plate 2. The water pipe is pre-buried in the concrete, and then the upper end of the water pipe is connected to an external circulating water pool through a water pump, and the lower end of the water pipe is connected to an external circulating water pool through a connecting pipe. When the water pump is started, water flow is always maintained in the water pipe, and the cooling component, the support component and the hanging component exchange heat inside the concrete with cold water in the water pipe, thereby taking away the heat inside the concrete and cooling the inside of the concrete.

[0004] In actual use, water pipes embedded in concrete are used to cool the interior and prevent concrete walls from cracking. The embedded water pipes cannot be reused and are relatively expensive. Moreover, the embedded water pipes in the wall often do not meet the design requirements. Based on this, the underground side walls are large-volume concrete pouring, and the hydration heat effect is obvious. The thicker the concrete wall, the higher the hydration heat and temperature stress will be, and the easier it will be to crack. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art that the pouring of underground side walls is significantly affected by hydration heat and temperature stress and is prone to cracks, and to propose a device for preventing concrete cracking of underground structure side walls.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a device for preventing concrete cracking of the side wall of an underground structure, comprising a mounting seat and a unit probe rod, the unit probe rod comprising a connecting sleeve, a transmission shaft is rotatably installed inside the connecting sleeve, a driving motor is fixedly installed on the top of the connecting sleeve, the top of the transmission shaft is fixedly connected to the rotating end of the driving motor, the bottom end of the transmission shaft extends to the outside of the connecting sleeve, and a spiral blade is fixedly installed on the bottom end surface of the transmission shaft.

[0007] An expansion hood is fixedly mounted on the surface of the connecting sleeve, the interior of the expansion hood is a closed cavity, and a communicating pipe is arranged on the surface of the expansion hood, which is communicated with the inner cavity of the expansion hood.

[0008] The mounting seat is fixedly mounted on the upper side of the template for pouring the side wall of the underground structure, the connecting sleeve is slidably inserted in the mounting seat, and the expansion hood is placed in the template pouring cavity. During the process of pouring concrete, the expansion hood is buried in the concrete, and a cooling medium is injected into the expansion hood to cool the center of the concrete, neutralize the hydration heat in the center of the concrete, reduce the temperature difference between the inside and the surface of the concrete wall, and help reduce the temperature stress concentration of the concrete, thereby achieving the effect of preventing concrete cracking.

[0009] Preferably, the expansion hood is a cylindrical hollow structure, and the upper and lower ends of the expansion hood are both conical structures. The expansion hood is made of aluminum plate, and the connecting pipe includes an input pipe and an output pipe. The input pipe and the output pipe are both fixedly installed on the surface of the connecting sleeve. The bottom end of the input pipe extends to the lower part of the inner cavity of the expansion hood, and the lower end of the input pipe extends to the upper part of the inner cavity of the expansion hood. The upper ends of the input pipe and the output pipe are fixedly installed with pipe joints, and the cooling medium is circulated into the expansion hood to improve the heat exchange efficiency.

[0010] Concrete is poured into the pouring cavity of the template, and the concrete covers the expansion cover. When the driving motor is started, the spiral blades drive the concrete to flow through the transmission shaft, so that the concrete is evenly distributed in the dead corners and corners of the steel cage, reducing the phenomenon of lack of slurry, small pits or bare bars on the concrete surface.

[0011] Preferably, a guide sleeve is fixedly installed at the end of the mounting seat, the guide sleeve is arranged vertically, the inner cavity of the guide sleeve is three through holes, the connecting sleeve, the input pipe and the output pipe are respectively slidably inserted into the through holes, and a vibrating rod is fixedly installed on the upper end surface of the connecting sleeve.

[0012] Concrete is poured in the pouring cavity of the template, and the concrete covers the expansion cover. When the driving motor and the vibrating rod are started, the reaction force of the spiral blade pushing the concrete and the vibration of the concrete around the expansion cover driven by the vibrating rod enable the unit probe rod to move upward. As the pouring depth of the concrete in the template increases, the unit probe rod automatically floats up, meeting the requirements of layered concrete distribution and vibration construction, and solving the quality problems caused by over-vibration or under-vibration, making concrete pouring more convenient.

[0013] Preferably, a steel cage is installed in the casting cavity of the template, and an insertion opening is reserved inside the steel cage. The unit probe rod is inserted into the insertion opening in the steel cage. A guide gap is reserved between the surface of the expansion hood and the inner wall of the template. The guide gap is relatively narrow. When concrete flows through the guide gap, the concrete can fully contact the surface of the expansion hood to exchange heat and achieve a better cooling effect.

[0014] Preferably, there are multiple mounting seats and unit probe rods, a mounting beam is fixedly installed on the upper side of the template, multiple mounting seats are fixedly installed on the mounting beam by bolts, the unit probe rods are arranged in parallel and are slidably connected to the mounting seats respectively, the arrangement quantity and position of the unit probe rods can be adjusted as needed, and after the concrete pouring is completed, the unit probe rods can be pulled out and reused.

[0015] The present invention has the following beneficial effects:

[0016] 1. The device for preventing concrete cracking proposed by the present invention selects a reasonable number of unit probes to be inserted into the center of the concrete side wall during the process of pouring concrete, and injects a cooling medium into the expansion hood to cool the center of the concrete, neutralize the hydration heat of the concrete center, delay the occurrence of the hydration peak, and reduce the temperature difference between the inside and outside of the concrete wall, which is beneficial to reducing the temperature stress concentration of the concrete and reducing the risk of temperature cracking. As the pouring work proceeds, the unit probe can be pulled out, so that there is no need to pre-buried water pipes and the effect of preventing concrete cracking is achieved.

[0017] 2. In the device for preventing concrete cracking proposed by the present invention, each unit probe rod is provided with a vibrating rod and a spiral blade. When the vibrating rod is in operation, the unit probe rod vibrates to expel bubbles in the concrete, compact the concrete, and at the same time loosen the concrete around the unit probe rod, thereby reducing the resistance of the concrete to the unit probe rod. In conjunction with the rotation of the spiral blade, the unit probe rod is provided with power to move upward. As the pouring depth of the concrete in the template increases, the unit probe rod automatically floats up, thereby meeting the requirements of layered concrete distribution and vibration construction.

[0018] 3. The device for preventing concrete cracking proposed by the present invention has spiral blades at the bottom of the unit probe rod. When the driving motor drives the spiral blades to rotate, the spiral blades promote the convection of concrete in the template casting cavity, so that the concrete is evenly distributed in the dead corners and corners of the steel cage, reducing the phenomenon of lack of slurry, small pits or bare bars on the concrete surface. This design makes up for the disadvantages that are easy to occur when vibrating dense concrete. Because, when vibrating concrete, the time, position and frequency of vibration are largely determined by the experience of the operator, there are disadvantages of over-vibration or under-vibration. Over-vibration will cause the coarse aggregate of concrete to sink and the coarse aggregate and mortar to separate from each other. If the vibration time is not enough, the concrete may not reach the required density, which increases the risk of cracking.

[0019] 4. The device for preventing concrete cracking proposed by the present invention arranges an expansion hood on the surface of the unit probe rod. When the unit probe rod floats up, the concrete mortar flows into the lower side of the expansion hood. At the same time, the rotating spiral blades stir the concrete on the lower side of the expansion hood to achieve re-mixing of coarse aggregate and mortar separated from each other due to vibration, thereby ensuring sufficient vibration and eliminating defects such as lack of concrete mortar, small pits or bare reinforcement. There is no need to worry about under-vibration, thus solving the quality problem of easy cracking caused by over-vibration or under-vibration and making concrete pouring more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the three-dimensional structure of the device for preventing concrete cracking proposed by the present invention;

[0021] Figure 2 for Figure 1 A schematic diagram of the structure enlargement at point A;

[0022] Figure 3 This is a schematic diagram of the front cross-section structure of the device for preventing concrete cracking proposed by the present invention;

[0023] Figure 4 A schematic diagram of the side cross-section structure of the device for preventing concrete cracking proposed by the present invention;

[0024] Figure 5 A partial schematic diagram of the side section structure of the device for preventing concrete cracking proposed by the present invention Figure 1 ;

[0025] Figure 6 A partial schematic diagram of the side section structure of the device for preventing concrete cracking proposed by the present invention Figure 2 .

[0026] In the figure: 1 mounting base, 2 connecting sleeve, 3 transmission shaft, 4 driving motor, 5 spiral blade, 6 expansion cover, 7 template, 8 vibrating rod, 9 input pipe, 10 output pipe, 11 pipe joint, 12 guide sleeve, 13 steel cage, 14 diversion gap, 15 mounting beam. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are 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 cannot be understood as a limitation on the present invention.

[0029] Reference Figure 1-Figure 6 A device for preventing concrete cracking of the side wall of an underground structure comprises a mounting base 1 and a unit probe rod, the unit probe rod comprises a connecting sleeve 2, a transmission shaft 3 is rotatably mounted inside the connecting sleeve 2, a driving motor 4 is fixedly mounted on the top of the connecting sleeve 2, the top of the transmission shaft 3 is fixedly connected to the rotating end of the driving motor 4, the bottom end of the transmission shaft 3 extends to the outside of the connecting sleeve 2, and a spiral blade 5 is fixedly mounted on the bottom end surface of the transmission shaft 3.

[0030] like Figure 4 As shown, a vibrating rod 8 is fixedly mounted on the upper end surface of the connecting sleeve 2.

[0031] An expansion hood 6 is fixedly mounted on the surface of the connecting sleeve 2 . The interior of the expansion hood 6 is a closed cavity. A communication pipe is provided on the surface of the expansion hood 6 . The communication pipe is communicated with the inner cavity of the expansion hood 6 .

[0032] Specifically, the expansion hood 6 is a cylindrical hollow structure, and the upper and lower ends of the expansion hood 6 are both conical structures. The expansion hood 6 is made of aluminum plate, and the connecting pipe includes an input pipe 9 and an output pipe 10. The input pipe 9 and the output pipe 10 are both fixedly installed on the surface of the connecting sleeve 2. The bottom end of the input pipe 9 extends to the lower part of the inner cavity of the expansion hood 6, and the lower end of the input pipe 9 extends to the upper part of the inner cavity of the expansion hood 6. The upper ends of the input pipe 9 and the output pipe 10 are fixedly installed with pipe joints 11.

[0033] A guide sleeve 12 is fixedly mounted on the end of the mounting seat 1. The guide sleeve 12 is arranged vertically. The inner cavity of the guide sleeve 12 is three through holes. The connecting sleeve 2, the input pipe 9 and the output pipe 10 are slidably inserted into the through holes respectively.

[0034] The mounting seat 1 is fixedly mounted on the upper side of the template 7 for pouring the side wall of the underground structure, the connecting sleeve 2 is slidably inserted into the guide sleeve 12 on the mounting seat 1, and the expansion cap 6 is placed in the pouring cavity of the template 7.

[0035] A steel cage 13 is installed in the casting cavity of the template 7. An insertion opening is reserved inside the steel cage 13. The unit probe is inserted into the insertion opening in the steel cage 13. A guide gap 14 is reserved between the surface of the expansion cover 6 and the inner wall of the template 7. Figure 4 shown.

[0036] In this embodiment, Figure 1 , Figure 2 As shown, there are multiple mounting seats 1 and unit probe rods, a mounting beam 15 is fixedly installed on the upper side of the template 7, multiple mounting seats 1 are fixedly installed on the mounting beam 15 by bolts, and the unit probe rods are arranged in parallel and slidably connected to the mounting seats 1 respectively. The arrangement quantity and position of the unit probe rods can be adjusted as needed. After the concrete pouring is completed, the unit probe rods can be pulled out and reused.

[0037] During the pouring of the side wall of the underground structure, concrete is poured in from the upper side of the formwork 7, and the concrete flows downward from the guide gap 14 until the expansion hood 6 is buried in the concrete. At the same time, the pipe joint 11 is connected to the cooling system through a hose, and a cooling medium is injected into the expansion hood 6 through the input pipe 9. The cooling medium absorbs the heat of the concrete outside the expansion hood 6 and is then discharged through the output pipe 10.

[0038] It should be noted that cooling water can be used as the cooling medium, and the cooling system refers to a circulating water pump. When construction is carried out in high temperature weather in summer, higher cooling requirements are placed on the cooling medium. Freon refrigerant can be used as the cooling medium, and the cooling system refers to a compressor. In addition, the diameter of the expansion hood 6 is determined by the size of the casting cavity of the template 7. When the thickness of the poured wall is large, a larger diameter expansion hood 6 is selected, and the size of the guide gap 14 is ensured to be sufficient for the mixed soil to pass through. The guide gap 14 is relatively narrow, and when the concrete flows through the guide gap 14, the concrete can fully contact the surface of the expansion hood 6 for heat exchange, thereby achieving a better cooling effect.

[0039] The device for preventing concrete cracking proposed by the present invention selects a reasonable number of unit probes to be inserted into the center of the concrete side wall during the process of pouring concrete, and injects a cooling medium into the expansion hood 6 to cool the center of the concrete, neutralize the hydration heat of the center of the concrete, delay the occurrence of the hydration peak, and reduce the temperature difference between the inside and the surface of the concrete wall, which is beneficial to reducing the temperature stress concentration of the concrete and reducing the risk of temperature cracking. As the pouring work proceeds, the unit probes can be pulled out, so that there is no need to pre-buried water pipes and the effect of preventing concrete cracking is achieved.

[0040] What needs to be strengthened is that there are many factors that lead to cracking of concrete structures, such as temperature changes, moisture changes, load effects, construction quality and material quality. Different design requirements and usage scenarios require different methods for solving concrete cracking. The present invention takes the pouring of large-volume concrete on the side walls of underground structures, which is affected by the pouring temperature and vibration construction as an example, and proposes a device to prevent concrete cracking.

[0041] In the process of pouring concrete, the material is poured in layers, such as Figure 3 or Figure 6 As shown, concrete is poured into the pouring cavity of the template 7, and the first poured concrete covers the expansion cover 6. The unit probe has a large volume at the location of the expansion cover 6. Under the buoyancy F1 of the concrete mortar and the resistance of the concrete to the expansion cover 6, the depth of the unit probe inserted into the concrete is fixed under normal conditions. When the drive motor 4 is started, the spiral blade 5 drives the concrete to flow through the transmission shaft 3, so that the concrete around the spiral blade 5 forms convection, as shown in FIG. Figure 3 and Figure 6 As shown by the dotted arrows around the spiral blade 5, it should be noted that the weight G of the unit probe can be adjusted by increasing or decreasing the amount of water injected into the expansion cover 6.

[0042] A spiral blade 5 is arranged at the bottom of the unit probe rod. When the driving motor 4 drives the spiral blade 5 to rotate, the spiral blade 5 promotes the convection of concrete in the casting cavity of the template 7, so that the concrete is evenly distributed in the dead corners and corners of the steel cage 13, and the phenomenon of lack of slurry, small pits or bare bars on the concrete surface is reduced. This design makes up for the disadvantages that are easy to occur when vibrating dense concrete. Because, when vibrating concrete, the time, position and frequency of vibration are largely determined by the experience of the operator, there are disadvantages of over-vibration or under-vibration. Over-vibration will cause the coarse aggregate of the concrete to sink and the coarse aggregate and mortar to separate from each other. If the vibration time is not enough, the concrete may not reach the required density, which increases the risk of cracking.

[0043] like Figure 5 , Figure 6 As shown, during the process of pouring concrete for the second time in the pouring cavity of the template 7, the driving motor 4 and the vibrating rod 8 are started simultaneously. Under the reaction force F2 of the spiral blade 5 pushing the concrete and the vibration of the concrete around the expansion cover 6 driven by the vibrating rod 8, the unit probe rod moves upward, and the expansion cover 6 enters the second poured concrete layer in the direction of F3 and cools the upper concrete layer. It should be noted that the concrete around the spiral blade 5 is flowing, and the unit probe rod cannot be lifted by the force of F2 alone. However, at this time, the vibrating rod 8 is started, and the concrete around the unit probe rod is loosened by vibration, thereby reducing the resistance of the concrete to the unit probe rod, and the unit probe rod can be slowly floated.

[0044] Each unit probe rod is provided with a vibrating rod 8 and a spiral blade 5. When the vibrating rod 8 is in operation, the unit probe rod vibrates to expel bubbles in the concrete and compact the concrete. At the same time, the concrete around the unit probe rod is loosened, reducing the resistance of the concrete to the unit probe rod. In conjunction with the rotation of the spiral blade 5, the unit probe rod is provided with upward power. As the pouring depth of the concrete in the template 7 increases, the unit probe rod automatically floats up, meeting the requirements of concrete layered distribution and vibration construction.

[0045] The device for preventing concrete cracking proposed by the present invention arranges an expansion cover 6 on the surface of the unit probe rod. When the unit probe rod floats up, the concrete mortar flows into the lower side of the expansion cover 6. At the same time, the rotating spiral blades 5 stir the concrete on the lower side of the expansion cover 6, so that the coarse aggregate and mortar separated from each other due to vibration are mixed again, thereby ensuring sufficient vibration, eliminating the defects of concrete lack of mortar, small pits or bare reinforcement, and eliminating the worry of insufficient vibration. The quality problem of easy cracking caused by over-vibration or insufficient vibration is solved, making concrete pouring more convenient.

[0046] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A device for preventing concrete cracking of a side wall of an underground structure, comprising a mounting seat (1) and a unit probe, characterized in that: The unit probe comprises a connecting sleeve (2), a transmission shaft (3) is rotatably mounted inside the connecting sleeve (2), a driving motor (4) is fixedly mounted on the top end of the connecting sleeve (2), the top end of the transmission shaft (3) is fixedly connected to the rotating end of the driving motor (4), the bottom end of the transmission shaft (3) extends outside the connecting sleeve (2), and a spiral blade (5) is fixedly mounted on the bottom end surface of the transmission shaft (3); An expansion hood (6) is fixedly mounted on the surface of the connecting sleeve (2), the interior of the expansion hood (6) is a closed cavity, and a communication pipe is arranged on the surface of the expansion hood (6), the communication pipe is communicated with the inner cavity of the expansion hood (6); The mounting seat (1) is fixedly mounted on the upper side of a template (7) for pouring a side wall of an underground structure, the connecting sleeve (2) is slidably inserted into the mounting seat (1), and the expansion cover (6) is placed in the pouring cavity of the template (7).

2. The device for preventing concrete cracking of the side wall of an underground structure according to claim 1, characterized in that: The expansion hood (6) is a cylindrical hollow structure, and both upper and lower ends of the expansion hood (6) are conical structures. The expansion hood (6) is made of an aluminum plate.

3. The device for preventing concrete cracking of the side wall of an underground structure according to claim 2, characterized in that: A vibrating rod (8) is fixedly mounted on the upper end surface of the connecting sleeve (2).

4. The device for preventing concrete cracking of the side wall of an underground structure according to claim 3, characterized in that: The communicating pipe comprises an input pipe (9) and an output pipe (10), the input pipe (9) and the output pipe (10) are both fixedly mounted on the surface of the connecting sleeve (2), the bottom end of the input pipe (9) extends to the lower part of the inner cavity of the expansion hood (6), the lower end of the input pipe (9) extends to the upper part of the inner cavity of the expansion hood (6), and the upper ends of the input pipe (9) and the output pipe (10) are both fixedly mounted with pipe joints (11).

5. The device for preventing concrete cracking of the side wall of an underground structure according to claim 4, characterized in that: A guide sleeve (12) is fixedly mounted on the end of the mounting seat (1), the guide sleeve (12) is arranged vertically, the inner cavity of the guide sleeve (12) is three through holes, and the connecting sleeve (2), the input pipe (9) and the output pipe (10) are respectively slidably inserted into the through holes.

6. The device for preventing concrete cracking of the side wall of an underground structure according to claim 5, characterized in that: A steel cage (13) is installed in the casting cavity of the template (7), an insertion opening is reserved inside the steel cage (13), the unit probe rod is inserted into the insertion opening in the steel cage (13), and a guide gap (14) is reserved between the surface of the expansion cover (6) and the inner wall of the template (7).

7. The device for preventing concrete cracking of the side wall of an underground structure according to claim 6, characterized in that: There are multiple mounting seats (1) and unit probe rods. A mounting beam (15) is fixedly mounted on the upper side of the template (7). Multiple mounting seats (1) are fixedly mounted on the mounting beam (15) by bolts. The unit probe rods are arranged in parallel and are slidably connected to the mounting seats (1) respectively.

8. The device for preventing concrete cracking of the side wall of an underground structure according to claim 7, characterized in that: Concrete is poured into the pouring cavity of the template (7), and the concrete covers the expansion cover (6). When the drive motor (4) is started, the spiral blades (5) drive the concrete to flow through the transmission shaft (3).

9. The device for preventing concrete cracking of the side wall of an underground structure according to claim 7, characterized in that: Concrete is poured into the pouring cavity of the template (7), and the concrete covers the expansion cover (6). When the driving motor (4) and the vibrating rod (8) are both started, the unit probe rod moves upwards due to the reaction force of the spiral blade (5) pushing the concrete and the vibration of the concrete around the expansion cover (6) driven by the vibrating rod (8).

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