Novel technology for grouting at lowest point of corrugated pipe with multiple pipes connected in series

Abstract

The invention relates to a novel technology for grouting the lowest point of a corrugated pipe with multiple pipes connected in series. The technology comprises the following steps that A, steel bars and corrugated pipes are bound; b, opening and communication of the corrugated pipe; c, pouring a beam body; d, tensioning the prestressed tendons, and sealing anchors; e, a grout stop valve is installed; f, grouting; and G, supplementing the slurry. According to the device, grouting is started from the lowest position of the corrugated pipe, residual air and moisture in the corrugated pipe can be easily discharged from a traditional grouting opening and a traditional slurry discharging opening along with rising of the liquid level, the grouting compactness is effectively improved, the corrugated pipes are connected in series, the multiple corrugated pipes are fully pressed at a time, the working efficiency is greatly improved, other equipment is not used, and the cost is reduced. The grouting method is similar to a traditional grouting process, and the cost and the grouting difficulty are basically not increased.

Description

Technical Field

[0001] The invention relates to the field of bridge construction engineering, in particular to a new process for grouting the lowest point of a multi-tube series-connected corrugated pipe. Background Art

[0002] Post-tensioned prestressed bridges have become the main form of bridge construction in my country due to their simple structure, high construction efficiency and low cost. However, the problem of low density of grouting in prestressed ducts has not been effectively solved. If the prestressed tendons are not well protected, their corrosion process will be greatly accelerated, seriously affecting the service life of the bridge and endangering public safety.

[0003] The low density of grouting is mainly caused by the residual air and moisture in the prestressed duct. During grouting, under the action of gravity, the slurry will first accumulate at the lowest point of the bellows, and then gradually spread to both sides. Since the sealing process has sealed both ends of the bellows, only the grouting port and the grouting outlet are left. The residual air on one side of the grouting port can neither be discharged from the grouting port nor from the grouting outlet, but can only be compressed near the grouting port, eventually forming a grouting cavity.

[0004] To solve the above problems, vacuum-assisted grouting, circulating grouting and other construction methods are currently mostly used. However, these solutions are costly on the one hand, and greatly increase the difficulty of workers' operation on the other hand. Therefore, in order to solve the quality problem of prestressed duct grouting, a new process with low cost, high efficiency and simple operation is urgently needed. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of low grouting density in traditional grouting technology, great difficulty in operation and high cost of existing improved solutions, and to propose a new process for grouting the lowest point of a multi-tube series-connected corrugated pipe.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a new process for grouting the lowest point of a multi-tube series-connected corrugated pipe, comprising the following steps: A. Tie up steel bars and corrugated pipes: Tie up steel frame structures and prestressed corrugated pipes according to drawings and bridge construction requirements; B. Opening and connecting the bellows: After step A, open the lowest point of the bellows at the bottom, use a PVC tube to keep the opening unobstructed, and open the side of the bellows at a nearby position to connect with the bottom opening of the second lowest bellows, also use a PVC tube to keep the connection unobstructed, and connect all the bellows in this way in turn; C. Casting the beam body: Cast the beam body according to the drawings and construction requirements, and keep the PVC pipes unobstructed; D. Tensioning and anchoring of prestressed tendons: tensioning and anchoring of prestressed tendons; E. Install the stop valve: Install the stop valve at each original grouting port and discharge port to prepare for grouting; F. Grouting: Start grouting from the opening reserved at the lowest point of the bottom bellows. The slurry gradually spreads from the bottom to both sides of the pipe and finally flows out from the slurry stop valves on both sides. Affected by gravity, the lower bellows are filled first, so the slurry stop valves emit thick slurry from low to high. When the thick slurry emerges, the slurry stop valve can be closed. When all the slurry stop valves are closed, the pressure maintenance process begins; G. Grouting: After the pressure maintenance is completed and the slurry is initially solidified, use an iron bar and an endoscope to observe the grouting density at the two ends of the bellows. The top two bellows must be inspected, and other bellows can be sampled. If there are defects, grouting must be done in time. The ends that do not emit thick slurry must be inspected and grouting must be done in time. After the slurry is completely solidified, the entire grouting process is completed.

[0007] Furthermore, steps B and A overlap in time, and when the steel bars and corrugated pipes are tied, it is necessary to consider whether the opening is convenient. In addition, in order to ensure the strength of the beam body, the opening positions of the corrugated pipes must be staggered, and the diameter of the PVC pipe cannot be too large.

[0008] Furthermore, the opening on the bellows is arranged in the lower middle part of the cross section of the bellows. Since the prestressed tendons are in a taut state after being stretched, they will fit on top of the bellows, and the opening from above will be blocked by the prestressed tendons.

[0009] Furthermore, the corrugated pipes are connected to each other through PVC pipes, and metal pipes cannot be used.

[0010] Furthermore, in step F, if the slurry emitting order of the slurry stop valve is not from low to high, it is necessary to record the ports where slurry is not emitted or the slurry emitting order is wrong for key inspection. When grouting with series bellows, if there is no slurry emission or the slurry emitting order is wrong, it means that the section of the bellows is seriously blocked. Key inspection of these areas and timely grouting will help ensure the quality of grouting.

[0011] Furthermore, in step G, after the slurry initially sets, it is necessary to check the density near the two higher bellows ports so as to find problems in time and replenish the slurry. The grouting quality of other bellows can be randomly inspected.

[0012] Furthermore, the positions of the bottom opening and the side opening of the corrugated pipe are staggered, and the inner diameter of the PVC pipe is 30-50 mm, which can reduce the impact on the strength of the beam body.

[0013] Furthermore, in step B, the bellows are interconnected in pairs, leaving two grouting ports, and four bellows are filled with grouting pressure in two times. The grouting pressure required for interconnecting in pairs is lower than that required for interconnecting all bellows, and a small grouting pump can be used.

[0014] Furthermore, in step B, the corrugated pipes are interconnected in pairs, leaving two grouting ports, and the corrugated pipes are filled with grouting twice or multiple times.

[0015] Furthermore, in the step B, at least two bellows are grouped together and connected in series. After the series connection, the bellows are filled up at least once.

[0016] Beneficial effects of the present invention: 1. Start grouting from the lowest point of the bellows. As the liquid level rises, the residual air and moisture in the bellows can be easily discharged from the traditional grouting and discharge ports, effectively improving the grouting density; 2. Connect the bellows in series and press multiple bellows at one time, which greatly improves the work efficiency; 3. No other equipment is used, and the grouting method is similar to the traditional process, which basically does not increase the cost and difficulty of grouting. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the specific implementation methods will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is the principle diagram of the grouting process at the lowest point of the bellows; Figure 2 This is a schematic diagram of the beam and bellows positions; Figure 3 Schematic diagram of beam cross section and bellows interconnection.

[0019] The reference numerals are as follows: 1. Corrugated pipe; 2. Lowest point of the corrugated pipe; 3. PVC pipe; 4. Side of the corrugated pipe; 5. Slurry outlet of the corrugated pipe; 6. Grouting outlet. DETAILED DESCRIPTION

[0020] The following is combined with Figure 1-3 The principles and features of the present invention are described, and the examples are only used to explain the present invention, and are not used to limit the scope of the present invention. It should be noted that the drawings are all simplified and do not use accurate proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0021] See also Figure 1-3 The present invention proposes a new process for grouting the lowest point of a multi-tube series-connected corrugated pipe, which specifically includes the following steps: A. Binding of steel bars and corrugated pipes 1: Bind the steel frame structure and prestressed corrugated pipes 1 according to the drawings and bridge construction requirements, while considering the opening position of each corrugated pipe 1 to reserve space for subsequent opening, connection and other operations.

[0022] B. Opening and connection of the bellows 1: After step A, a grouting port 6 is opened at the lowest point 2 of the lowest bellows, and a PVC pipe 3 is used to keep the opening open. An opening is made on the side 4 of the bellows to connect with the bottom opening of the second lowest bellows 1, and a PVC pipe 3 is also used to keep the connection open. In this way, all the bellows 1 are connected in sequence.

[0023] C. Casting the beam body: Cast the beam body according to the drawings and construction requirements, and ensure that the openings and PVC pipe 3 connections are unobstructed.

[0024] D. Tensioning and anchoring of prestressed tendons: The tensioning and anchoring processes of prestressed tendons are carried out according to traditional methods.

[0025] E. Install the slurry stop valve: Install a slurry stop valve at the slurry outlet 5 of each bellows.

[0026] F. Grouting: Start grouting from the lowest point 2 of the lowest bellows at the grouting port 6. The slurry accumulates at the bottom under the action of gravity and gradually spreads to both sides of the bellows 1. At the same time, the remaining air and water in the pipeline are discharged to the slurry outlet 5 of the bellows. At this time, the traditional grouting port and the slurry outlet both play the role of the slurry outlet 5. When thick slurry emerges, the slurry stop valve is closed. After all the slurry stop valves are closed, the pressure maintaining process begins.

[0027] G. Grouting: After the pressure maintenance is completed and the slurry is initially solidified, use an iron chisel and an endoscope to observe the grouting density at the 5 slurry outlets of the bellows. The top two bellows 1 must be inspected, and other bellows 1 can be sampled. If there are defects, grouting must be done in time. The ports that do not emit thick slurry must be inspected and grouting must be done in time. After the slurry is completely solidified, the entire grouting process is completed.

[0028] The above-mentioned embodiment provides a new process for grouting the lowest point of a multi-tube series-connected corrugated pipe, which changes the grouting port in the traditional grouting process into a grouting outlet, and starts grouting from the bottom, thus avoiding the problem that air cannot be discharged from the grouting port under the traditional scheme. Compared with other vacuum-assisted grouting and circulating grouting methods, the new process has lower cost and simpler operation.

[0029] Furthermore, in the above step B, during the opening and connection processing, the openings are staggered as much as possible, and the diameter of the PVC pipe 3 used for connection is controlled within 30-50 mm.

[0030] The beneficial effect of adopting the above further solution is that it can minimize the influence of structures such as openings and connecting pipes on the strength of the beam body.

[0031] Furthermore, in the above step B, all pipelines may be connected in series to partial pipelines and grouting may be performed multiple times according to actual working conditions.

[0032] The beneficial effect of adopting the above further scheme is that partial series connection and multiple grouting are suitable for grouting pumps with smaller power, and the grouting density is higher than that of full series grouting, but its efficiency will be reduced to a certain extent.

[0033] Furthermore, in the above step B, all openings cannot be opened on the upper side of the corrugated tube 1 .

[0034] The beneficial effect of adopting the above further solution is that the prestressed tendons will be tightened after being tensioned and attached to the upper side of the corrugated pipe 1. Not having an opening on the upper side can effectively prevent the prestressed tendons from blocking the grouting channel.

[0035] Furthermore, in the above step F, when grouting, attention should be paid to observing the slurry emission sequence of each slurry stop valve. If it is not from low to high, the ports with wrong slurry emission sequence should be recorded and focused on inspection after initial setting.

[0036] The beneficial effect of adopting the above further scheme is that once the series grouting of the corrugated pipe 1 is blocked, it often leads to a large area of ​​​​ungrouted area. Recording the grouting situation helps to quickly discover defects during grouting.

[0037] The specific working principle of the present invention is: in order to avoid the accumulation of residual air on the grouting port side, grouting is started directly from the opening of the lowest point 2 of the bellows, and the grouting port in the traditional process is changed to the slurry outlet 5. As the slurry liquid level continues to rise and spread to both sides of the bellows, the residual air and water will be smoothly discharged from the slurry outlet 5 of the bellows, thereby effectively improving the grouting density.

[0038] The method of using the present invention is as follows: in the process of tying the steel bars and the corrugated pipe 1, the opening position of the corrugated pipe 1 is considered and a certain space is reserved; a grouting port 6 is opened at the lowest point 2 of the lowest corrugated pipe, and the opening on the side 4 is connected to the bottom opening of the second lowest corrugated pipe 1, and all the corrugated pipes 1 are connected in this way, and the channel is maintained with a PVC pipe 3; the beam body is cast, the prestressed tendons are tensioned, and the anchors are sealed according to the traditional process; when grouting, grouting is started from the grouting port 6 reserved at the lowest point 2 of the lowest corrugated pipe, and the stop valve of the corrugated pipe slurry outlet 5 is closed when thick slurry emerges, and the pressure is maintained after all the stop valves are closed; after initial setting, the density of the corrugated pipes 1 that have not emitted thick slurry or have emitted slurry in the wrong order is preferentially detected, the two highest corrugated pipes 1 must be detected, and the other corrugated pipes 1 can be randomly inspected, and whether to add slurry is determined based on the test results; after the slurry is completely solidified, the entire grouting process is completed.

[0039] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A new process for grouting the lowest point of a multi-tube series-connected corrugated pipe, characterized in that: The following steps are involved: A. Tie up steel bars and corrugated pipes: Tie up steel frame structures and prestressed corrugated pipes according to drawings and bridge construction requirements; B. Opening and connecting the bellows: After step A, open the lowest point of the bellows at the bottom, use a PVC tube to keep the opening unobstructed, and open the side of the bellows at that point to connect with the bottom opening of the second lowest bellows, also use a PVC tube to keep the connection unobstructed, and connect all the bellows in this way in turn; C. Casting the beam body: Cast the beam body according to the drawings and construction requirements, and keep the PVC pipes unobstructed; D. Tensioning and anchoring of prestressed tendons: tensioning and anchoring of prestressed tendons; E. Install grout stop valves: Install grout stop valves at both ends of the bellows to prepare for grouting; F. Grouting: Start grouting from the opening reserved at the lowest point of the bottom bellows. The slurry gradually spreads from the bottom to both sides of the pipe and finally flows out from the slurry stop valves on both sides. Affected by gravity, the lower bellows are filled first, so the slurry stop valves emit thick slurry from low to high. When the thick slurry emerges, the slurry stop valve can be closed. When all the slurry stop valves are closed, the pressure maintenance process begins; G. Grouting: After the pressure maintenance is completed and the slurry is initially solidified, use an iron chisel and an endoscope to observe the density of the grouting at the two ends of the bellows. At least the top two bellows should be inspected, and other bellows should be randomly inspected. If there are defects, grouting must be done in time. The ports where no thick slurry emerges must be inspected and grouting must be done in time. After the slurry is completely solidified, the entire grouting process is completed.

2. According to claim 1, a new process for grouting the lowest point of a multi-tube series-connected corrugated pipe, characterized in that: Steps B and A overlap in time. When the steel bars and corrugated pipes are tied, it is necessary to consider whether the opening is convenient. In addition, in order to ensure the strength of the beam, the opening positions of the corrugated pipes must be staggered, and the diameter of the PVC pipe cannot exceed the preset size.

3. According to claim 2, a new process for grouting the lowest point of a multi-tube series-connected corrugated pipe is characterized in that: The opening on the bellows is arranged at the lower middle part of the cross section of the bellows.

4. According to claim 3, a new process for grouting the lowest point of a multi-tube series-connected corrugated pipe is characterized in that: The corrugated pipes are connected to each other through PVC pipes, and metal pipes cannot be used.

5. According to claim 4, a new process for grouting the lowest point of a multi-tube series-connected corrugated pipe is characterized in that: In the step F, if the slurry emitting sequence of the slurry stop valves is not from low to high, it is necessary to record the ports where slurry is not emitted or where the slurry emitting sequence is wrong and conduct key inspections.

6. According to claim 5, a new process for grouting the lowest point of a multi-tube series-connected corrugated pipe is characterized in that: In step G, after the slurry initially sets, the density near the two higher bellows ports is checked so that problems can be discovered and grouting can be performed in time, and the grouting quality of other bellows is randomly inspected.

7. The new process for grouting the lowest point of a multi-tube series-connected corrugated pipe according to claim 6 is characterized in that: The bottom opening and the side opening of the corrugated pipe are staggered, and the inner diameter of the PVC pipe is 30-50 mm.

8. The new process for grouting the lowest point of a multi-tube series-connected corrugated pipe according to claim 7 is characterized in that: In the step B, at least two bellows are connected in series as a group, and after being connected in series, the bellows are filled up at least once.

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