A rigid-flexible combined in-pipe hoop prestress reinforcement method

Abstract

The present application relates to a kind of rigid-flexible combined pipe internal hoop prestress reinforcement method, comprising: equipment, expansion and pre-stress, grouting and bonding and other steps.The rigid-flexible combined pipe internal hoop prestress reinforcement method provided by the present application uses carbon fiber pre-tension ring and steel lining pre-pressure ring to jointly reinforce;It is the hoop combined material ring of rigid (compression) -flexible (tension) combination that replaces the original single flexible (tension) material ring, and the combination of high-strength carbon fiber material and high-elasticity steel with low compression is fully utilized.The pre-tension stress part of carbon fiber ring is balanced by the pre-pressure stress of high-strength steel ring, and the pre-tension stress of another part of carbon fiber ring is balanced by the bonding force between carbon plate and pipe inner wall concrete.

Description

TECHNICAL FIELD

[0001] The present application relates to a rigid-flexible combined pipe internal hoop prestress reinforcement method, and belongs to the technical field of reinforcement engineering. BACKGROUND

[0002] PCCP is the abbreviation of Prestressed Concrete Cylinder Pipe, which refers to a composite pipe material composed of a steel cylinder with a socket at both ends and a concrete layer inside and outside the steel cylinder, and a high-strength steel wire wound on the outer wall of the pipe core, and a protective layer of rolled cement mortar.

[0003] Nanjing Hydraulic Science Research Institute has proposed a series of patent technologies for PCCP pipe wire reinforcement and reinforcement, including "a pipe internal hoop prestress repair and reinforcement system", "a pipe internal tire type air pressure loading hoop prestress reinforcement device", "a device for filling and curing material hoop prestress reinforcement in high-pressure elastic pipe", etc. Through theory, test, and engineering application, it is found that the guarantee of the adhesion reliability between the hoop prestress material (such as carbon fiber plate) and the pipe inner wall is one of the key points of the technology, and the typical failure mode is that the adhesion is found to be unreliable in some places, which will cause a small piece of failure to peel off near the place.

[0004] In the test research and engineering application, the methods such as roughening the concrete surface of the pipe inner wall, penetrating the surface of the structure glue, and reasonably controlling the prestress are used to improve the adhesion reliability and reduce the risk of adhesion.

[0005] However, the local adhesion of single carbon fiber plate also faces the risk of rapid expansion, and since defects are inevitable, the adhesion stress control value of carbon fiber plate is low; this is the inevitable risk of the characteristics of carbon fiber plate material and the prestress it bears. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a pipe internal hoop prestress reinforcement method capable of improving the reliability of pipe internal hoop prestress reinforcement.

[0007] To solve the above technical problems, the technical solution provided by the present application is as follows: a rigid-flexible combined pipe internal hoop prestress reinforcement method, comprising the following steps:

[0008] (1) According to the diameter, design internal pressure, and enhanced reinforcement bearing capacity of the pipe to be reinforced, select appropriate steel expansion ring and carbon fiber plate; the side wall of the steel expansion ring has a notch and can expand, and the steel expansion ring can maintain stress after the notch is supplemented with a connecting section; the steel expansion ring has a plurality of grouting nozzles capable of grouting to the outside of the steel expansion ring;

[0009] (2) cleaning the pipe wall of the part to be reinforced;

[0010] (3) brushing the outer surface of the steel expansion ring with structural glue having the properties of slow curing and lubrication, and pasting the carbon fiber plate on the outer surface of the steel expansion ring;

[0011] (4) supporting the steel expansion ring with a steel truss, and having an air bag between the steel truss and the steel expansion ring;

[0012] (5) inflating the air bag to expand, and at the same time, the steel expansion ring expands, so that the tensile strain stress of the carbon fiber plate reaches the required value;

[0013] (6) filling the slurry into the gap between the carbon fiber plate and the pipe wall of the part to be reinforced through the grouting nozzle;

[0014] (7) after the grouting is completed, removing the steel truss and the air bag.

[0015] The further improvement of the above scheme is that the expansion method of the steel expansion ring is to use a plurality of synchronous jacks at the gap of the steel expansion ring to expand the steel expansion ring, and after the tensile strain stress of the carbon fiber plate reaches the required value, the steel expansion ring is locked by using a connecting section.

[0016] The further improvement of the above scheme is that the gap of the steel expansion ring has a side lug for mounting the synchronous jack.

[0017] The further improvement of the above scheme is that the expansion method of the steel expansion ring is to use a cooling plate; the cooling plate has a cold liquid pipe inside; the cooling plate is tightly attached to the inner side wall of the steel expansion ring; the temperature of the steel expansion ring is lowered in advance by the cold liquid in the cooling plate, and when the steel expansion ring reaches the required deformation, the steel expansion ring is locked by using a connecting section, and then the cooling plate stops working, and then the steel expansion ring restores the temperature to expand.

[0018] The further improvement of the above scheme is that the cooling plate is made of aluminum, and the side away from the steel expansion ring is covered with a heat preservation layer, and the side facing the steel expansion ring has a plurality of magnets.

[0019] The further improvement of the above scheme is that the outer side wall of the steel expansion ring has a groove to accommodate the carbon fiber plate.

[0020] The further improvement of the above scheme is that the outer side wall of the steel expansion ring has a sealing ring at both ends.

[0021] The further improvement of the above scheme is that the inner side wall of the steel expansion ring and the air bag are lubricated.

[0022] The further improvement of the above scheme is that the two ends of the steel expansion ring have a limiting ring capable of restraining the air bag.

[0023] A further improvement to the above solution is that the airbag has a metal armor at the notch corresponding to the steel expansion ring.

[0024] The present invention provides a rigid-flexible combined circumferential prestressing reinforcement method for pipes, which uses a carbon fiber prestressed ring and a steel lining prestressed ring for joint reinforcement. It replaces the original single flexible (tensile) material ring with a rigid (compression)-flexible (tension) combined circumferential composite material ring, fully utilizing the high strength and low elastic modulus and large deformation performance (large elongation characteristics) of carbon fiber material, and the high elastic modulus and low compressibility of high-strength steel. The prestress of the carbon fiber ring is balanced by the prestress of the high-strength steel ring, while the other part of the prestress of the carbon fiber ring is balanced by the bond force between the carbon plate and the concrete of the inner wall of the pipe. Attached Figure Description

[0025] The invention will now be further described with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic diagram of a preferred embodiment 1 of the present invention.

[0027] Figure 2 This is a top view of the synchronous jack position in Example 1.

[0028] Figure 3 This is a schematic diagram of the bottom structure of Example 1.

[0029] Figure 4 This is a schematic diagram of the top structure of Embodiment 1.

[0030] Figure 5 This is a schematic diagram of the structure after the completion of construction in Example 1.

[0031] Figure 6 This is a schematic diagram of a preferred embodiment 2 of the present invention.

[0032] Figure 7 This is a schematic diagram of the cooling plate structure in Example 2.

[0033] Figure 8 This is a schematic diagram of the bottom structure in Example 2. Detailed Implementation

[0034] Example 1: The rigid-flexible combined circumferential prestressed reinforcement method for pipes in this example includes the following steps:

[0035] (1) According to the situation of the pipe to be reinforced, that is, the diameter of the pipe to be reinforced, the design internal pressure, the situation of the pipe to be reinforced, etc., through engineering design, the appropriate steel expansion ring 3, carbon fiber plate 4 are selected; wherein the steel expansion ring 3 can be spliced according to the size, weight, etc.; the spliced sections can be bolted, welded, directly connected, etc. The side wall of the steel expansion ring 3 is provided with a notch, so that the steel expansion ring 3 can be expanded, and after the expansion of the steel expansion ring 3, a connecting section 6 is supplemented at the notch of the steel expansion ring 3, so that the steel expansion ring 3 can maintain stress; the steel expansion ring 3 is provided with a plurality of grouting nozzles 10 capable of grouting to the outside of the steel expansion ring 3; the outer side wall of the steel expansion ring 3 is provided with a groove for accommodating the carbon fiber plate 4.

[0036] (2) Clean the pipe wall of the part to be reinforced; expose the clean concrete surface.

[0037] (3) If the steel expansion ring 3 needs to be spliced, splice it, then apply structural adhesive to the groove on the outer side wall of the steel expansion ring 3, the structural adhesive has the characteristics of slow curing and lubrication; spread the carbon fiber plate 4 to the natural state and place it in the groove of the steel expansion ring 3 to form a carbon fiber plate ring, and the two are bonded by the structural adhesive.

[0038] Install the synchronous jack 5 at the notch of the steel expansion ring 3; in order to facilitate the installation of the synchronous jack 5, the notch of the steel expansion ring 3 is provided with a side ear 8 for installing the synchronous jack 5. During this step, the steel expansion ring 3 and the carbon fiber plate 4 should be basically close and at a low stress level.

[0039] (4) This step should be synchronized with the previous step, and the steel truss 1 is assembled. The steel truss 1 is used to support the steel expansion ring 3 and provide counterforce support during the expansion process; the air bag 2 is arranged between the steel truss 1 and the steel expansion ring 3. The assembled structure is shown in Figure 1 , Figure 2 and Figure 3 .

[0040] (5) Implement expansion, inflate the air bag 2, and at the same time, start the synchronous jack 5 to synchronize and coordinate the expansion of the steel expansion ring 3 and the air bag 2; after the tensile stress of the carbon fiber plate 4 reaches the required value, use the connecting section 6 to lock the steel expansion ring 3; the relevant values are given by design calculation, and the final judgment is made on air pressure, jack load, total compression amount of the expansion ring, compression stress, tensile stress of the carbon fiber plate, and stress monitoring value of the connecting section. The connecting section 6 has different sizes, and the appropriate one is selected by the final size of the notch, and the size of the connecting section 6 meets the allowable deviation value.

[0041] After that, the synchronous jack 5 can be removed, and the synchronous jack 5 is gradually unloaded, and the stress is balanced by the steel expansion ring 3, the carbon fiber plate 4, and the steel truss 1.

[0042] (6) As shown in Figure 4As shown, grouting is carried out through the grouting nozzle 10, and the slurry fills the gap between the carbon fiber plate 4 and the pipe wall 11 of the part to be reinforced; the grouting nozzles 10 are arranged along the circumference of the steel expansion ring 3, and the grouting is started from the grouting nozzle 10 at the lowest position, and when the adjacent grouting nozzle discharges, the grouting nozzle above continues to grout; in this way, it can be ensured that there is no air bubble defect between the carbon fiber plate 4 and the pipe wall 11. The grouting nozzle 10 adopts a quick connection type; the grouting slurry solidifying agent is configured, on the one hand, to avoid the release of excessive heat during solidification, which may cause the steel expansion ring 3 to compress too much; on the other hand, to avoid affecting the time period of disassembling the loading device during the solidification time process, thereby affecting the total efficiency of the reinforcement.

[0043] (7) After the grouting slurry is solidified, the auxiliary structures such as the steel truss 1 and the air bag 2 are removed. The final structure is as shown in Figure 5 The slurry layer, the carbon fiber plate ring and the steel ring are sequentially arranged inward from the pipe wall 11. The carbon fiber plate ring and the steel ring are both pre-stressed, and after being combined, the carbon fiber plate ring is in tension and the steel ring is in compression; after reinforcement, the carbon fiber plate and the inner wall of the PCCP pipe are in adhesive tension, and the steel ring supports and protects the carbon fiber plate ring; during operation, the internal water pressure acts on the composite inner lining pipe, and the internal pre-tension of the carbon fiber plate and the adhesive tension are balanced by part of the internal water pressure.

[0044] In order to avoid the overflow of the slurry from the end, the outer side wall of the steel expansion ring 3 has a sealing ring 9 at both ends.

[0045] In order to prevent the air bag 2 from protruding from the end, the steel expansion ring 3 has a limiting ring capable of restraining the air bag 2 at both ends.

[0046] Because of the sliding and friction between the steel expansion ring 3 and the carbon fiber plate 4 during the expansion process, the structural adhesive between the steel expansion ring 3 and the carbon fiber plate 4 cannot be in a completely solidified state. Therefore, steps (3) and (4) are synchronized to minimize the solidification time of the structural adhesive and make it more fluid. The steel expansion ring 3 and the carbon fiber plate 4 are lubricated to avoid damaging the carbon fiber plate 4.

[0047] Because of the non-uniformity of the ellipticity and structural stiffness of the steel expansion ring 3, there is still shear stress between the interface of the steel expansion ring 3 and the carbon fiber plate 4, and the interface needs to be bonded and strengthened; therefore, the structural adhesive needs to meet the requirements of small fluidity, relatively long solidification time, high strength, etc.

[0048] In order to avoid the air bag 2 from protruding from the notch, the air bag 2 has a metal armor 7 corresponding to the notch of the steel expansion ring 3.

[0049] Embodiment 2: The rigid-flexible combined pipe internal circumferential pre-stress reinforcement method of this embodiment is mostly the same as that of embodiment 1, and the different part is that the expansion mode of the steel expansion ring 3 is thermal expansion and cold contraction expansion.

[0050] As shown in Figure 6 and Figure 7As shown, instead of using the jack as in Example 1, a cooling plate 12 is used. The cooling plate 12 is in close contact with the inner wall of the steel expansion ring 3.

[0051] like Figure 8 As shown, the cooling plate 12 is made of aluminum and contains a coolant pipe 12a. Several magnets 12b are located on the side facing the steel expansion ring 3, while the remaining sides are covered with an insulation layer 12c. When the steel expansion ring 3 needs to expand, the coolant inside the cooling plate 12 pre-cools the steel expansion ring 3, causing it to shrink and the gap to widen. Once the designed size is reached, the connecting section locks the steel expansion ring, the cooling plate stops working, and the steel expansion ring slowly recovers its temperature, thus expanding.

[0052] This invention is not limited to the specific technical solutions described in the above embodiments. Besides the above embodiments, this invention may have other implementation methods. All technical solutions formed by equivalent substitutions are within the scope of protection claimed by this invention.

Claims

1. A rigid-flexible combined method for in-pipe hoop prestressed reinforcement, characterized in that, It comprises the following steps: (1) According to the condition of the pipe to be reinforced, select the appropriate steel expansion ring and carbon fiber plate; the side wall of the steel expansion ring has a notch and can be expanded, and a connecting section is added at the notch of the steel expansion ring after expansion, so that the steel expansion ring can maintain stress; the steel expansion ring has a plurality of grouting nozzles that can grout to the outside of the steel expansion ring; (2) Clean the pipe wall of the part to be reinforced; (3) Apply structural adhesive to the outer surface of the steel expansion ring and attach the carbon fiber plate to the outer surface of the steel expansion ring; (4) Use a steel truss to support the steel expansion ring; the steel truss and the steel expansion ring have an air bag therebetween; (5) Inflate the air bag to expand, and at the same time, the steel expansion ring expands; make the tensile strain stress of the carbon fiber plate reach the required value; the method of expanding the steel expansion ring is to use a cooling plate; the cooling plate has a cold liquid pipe inside; the cooling plate is tightly attached to the inner side wall of the steel expansion ring; the temperature of the steel expansion ring is lowered in advance by the cold liquid in the cooling plate; when the steel expansion ring reaches the required deformation, the connecting section is used to lock the steel expansion ring, and then the cooling plate stops working, and then the steel expansion ring restores temperature and expands; (6) Grouting is carried out through the grouting nozzles, and the grout fills the gap between the carbon fiber plate and the pipe wall of the part to be reinforced; (7) After the grout is cured, remove the steel truss and the air bag.

2. The rigid-flexible combined in-pipe hoop prestress reinforcement method according to claim 1, characterized in that: The method of expanding the steel expansion ring is to use a plurality of synchronous jacks at the notch to expand the steel expansion ring, and after the tensile strain stress of the carbon fiber plate reaches the required value, the connecting section is used to lock the steel expansion ring.

3. The rigid-flexible combined in-pipe hoop prestress reinforcement method according to claim 2, characterized in that: The notch of the steel expansion ring has a side ear for mounting the synchronous jack.

4. The rigid-flexible combined in-pipe hoop prestress reinforcement method according to claim 1, characterized in that: The cooling plate is made of aluminum, and the side away from the steel expansion ring is covered with a heat preservation layer, and the side facing the steel expansion ring has a plurality of magnets.

5. The rigid-flexible combined in-pipe hoop prestress reinforcement method according to claim 1, characterized in that: The outer side wall of the steel expansion ring has a groove to accommodate the carbon fiber plate.

6. The rigid-flexible combined in-pipe hoop prestress reinforcement method according to claim 1, characterized in that: The outer side wall of the steel expansion ring has a sealing ring at both ends.

7. The rigid-flexible combined in-pipe hoop prestress reinforcement method according to claim 1, characterized in that: The outer side wall of the steel expansion ring and the carbon fiber plate are lubricated.

8. The rigid-flexible combined in-pipe hoop prestress reinforcement method according to claim 1, characterized in that: The two ends of the steel expansion ring have a limiting ring that can constrain the air bag.

9. The rigid-flexible combined in-pipe hoop prestress reinforcement method according to claim 1, characterized in that: The air bag has a metal armor corresponding to the notch of the steel expansion ring.

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