Steel pipe intersecting joint bearing performance reinforcing device and reinforcing method thereof

Abstract

The application discloses a kind of steel pipe intersecting node bearing performance reinforcing method, comprising: opening into mould mouth and grouting mouth at steel pipe node;Into mould mouth is loaded into air bag part to steel pipe, air bag part is inflated to saturated state, and a material injection chamber is formed at steel pipe inner node;Positioning part is inserted into steel pipe interior by into mould mouth, and placed below air bag part;From grouting mouth, reinforcing slurry is injected, and annular grouting reinforcement is formed by standing and solidifying, and positioning part is pulled out;Air bag part is taken out, and into mould mouth and grouting mouth are blocked.This method is reinforced after steel pipe, and compression and tensile performance is significantly improved, can effectively improve structural performance and reduce structure deadweight;The application further discloses a kind of steel pipe intersecting node bearing performance reinforcing device, including air bag part and positioning part, air bag part is used to form the material injection chamber of injection reinforcing slurry in steel pipe node;Positioning part is used to support the air bag part and annular grouting reinforcement.This device structure is simple, and convenient to use.

Description

Technical Field

[0001] This invention belongs to the technical field of steel pipe joint reinforcement equipment, specifically to a steel pipe intersection joint load-bearing capacity reinforcement device and reinforcement method. Background Technology

[0002] The load-bearing capacity of intersecting steel pipe joints is an important indicator of the overall performance and safe service of large-span spatial structures and offshore jacket platforms.

[0003] Existing measures to strengthen the load-bearing capacity of steel pipe intersection joints are mostly external reinforcements. For example, document CN114658255A discloses a saddle plate reinforcement structure for K-shaped intersection joints. This structure strengthens the steel pipe joint by welding a steel plate to the outside of the steel pipe intersection joint. However, the thermal stress generated by welding the steel plate will change the properties of the steel in the joint area, resulting in new stress concentration and residual deformation. Meanwhile, document CN104233964B discloses a CFRP cloth reinforcement structure for steel pipe intersection joints of steel truss bridges. This structure can strengthen the steel pipe joint, but pasting CFRP cloth can only improve the tensile performance of the joint and cannot prevent the joint area from crushing. This is not suitable for large offshore jacket structures and underwater operations.

[0004] In the prior art, there are also methods for reinforcing the inside of steel pipes. For example, [Lan Yifei. Study on the static compressive performance of the branch pipe of the T-shaped intersection node of circular steel pipe and concrete [D]. Xihua University, 2022.] proposed a method of solidly filling the inside of the steel pipe node with concrete. However, for the steel pipe intersection node with a large cross-sectional size, the solid filling of concrete will inevitably significantly increase the self-weight of the node, which may cause a change in the force transmission mechanism of the overall spatial structure, resulting in changes in the stress state of some structural components or even making them weak components. It is difficult to guarantee the reinforcement effect of the overall structure. At the same time, the solid filling of concrete reinforcement method will not be able to achieve the connectivity at the steel pipe node, and will not be able to meet the requirements of water injection and straightening during the installation of the jacket. Summary of the Invention

[0005] To address the problem that traditional steel pipe joint reinforcement methods, which use external welded steel plates, CFRP fabric bonding, and internal solid concrete filling, cannot guarantee the connectivity of the steel pipe joint while improving the compressive and tensile performance of the steel pipe, this invention provides a steel pipe intersection joint load-bearing capacity reinforcement device and method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention discloses a method for strengthening the load-bearing capacity of intersecting steel pipe joints, characterized by comprising the following steps:

[0008] S1. Open the mold inlet and grouting inlet at the steel pipe joint;

[0009] S2. Insert the air bladder into the steel pipe through the mold inlet, inflate the air bladder to saturation, and form an injection chamber at the node inside the steel pipe.

[0010] S3. Insert the positioning part into the steel pipe through the mold inlet and place it below the airbag part;

[0011] S4. Inject the reinforcing grout through the grouting port, let it stand to solidify and form a ring-shaped grouting and reinforcing body, and then pull out the positioning part.

[0012] S5. Remove the air bladder and seal the mold inlet and grout injection port.

[0013] Preferably, the diameter of the mold inlet in S1 is less than 2 cm.

[0014] Preferably, the length of the injection chamber in S2 is 2 to 4 times the diameter of the steel pipe.

[0015] Preferably, the airbag portion in S2 is manufactured and assembled by hot pressing.

[0016] Preferably, the reinforcing slurry in S3 is one or more of epoxy resin, graphene-reinforced cement, and cement slurry.

[0017] Preferably, during the process of removing the airbag part in S5, the gas in the airbag part is discharged through the exhaust port and removed from the mold inlet.

[0018] If the annular grouting solid adheres to the air bladder, the gas in the air bladder should be removed first, and an organic solvent should be injected into the air port of the air bladder to dissolve the air bladder.

[0019] The present invention also discloses a device for reinforcing the load-bearing capacity of intersecting steel pipe joints, which is applied in the above-mentioned method. The device includes an air bladder and a positioning part. The air bladder is used to form an injection chamber for injecting reinforcing slurry in the steel pipe joint.

[0020] The airbag section includes a limiting airbag and an injection airbag, with the two ends of the limiting airbag respectively connected to the injection airbag.

[0021] The positioning part is used to support the airbag part and the annular grouting solidification part.

[0022] Preferably, the wall thickness of the grouting part airbag and the limiting part airbag is 0.3 to 2 mm.

[0023] Preferably, the positioning part includes a connecting platform, a support plate is provided on the connecting platform, a connecting plate is rotatably connected to the support plate, a spring is connected between the connecting plate and the support plate, a rotating column is rotatably mounted on the connecting platform, one end of a connecting strip is wound on the rotating column, the other end of the connecting strip is fixedly connected to the connecting platform, and the inner wall of the connecting strip connects the ends of the connecting plate and the support plate.

[0024] Preferably, the connecting strip is made of elastic steel.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] This invention discloses a method for strengthening the load-bearing capacity of intersecting steel pipe joints. The method involves inserting an airbag through an inlet at the pipe joint, creating a chamber at the joint that can hold and inject a certain amount of grout. The injected grout forms a reinforced structure within the steel pipe at the joint, thus strengthening the pipe. This reinforcement method is simple to operate and convenient to use. After reinforcement, the pipes at the reinforced location remain interconnected, without affecting the internal connectivity of the steel pipe, thereby enabling water injection and alignment of the guide frame. The reinforced steel pipes do not affect the structural appearance or normal function, significantly reducing the self-weight of the reinforcement and enabling underwater operations. Furthermore, the reinforced steel pipe joints not only improve compressive strength but also tensile strength.

[0027] Furthermore, the diameter of the mold inlet in this method is less than 2cm, which ensures the safe insertion of the air bladder. This diameter setting does not affect the structural strength of the steel pipe and guarantees the service life of the steel pipe.

[0028] Furthermore, the length of the limiting airbag proposed in this method is 2 to 4 times the diameter of the steel pipe, which increases the reinforcement strength of the steel pipe joint by the device.

[0029] Furthermore, in this method, after the reinforcing grout solidifies to form a ring-shaped grouting reinforcement body and adheres to the air bladder, the air bladder is dissolved to remove the air bladder inside the steel pipe, ensuring the connectivity of the steel pipe located at the ring-shaped grouting reinforcement body.

[0030] This invention also discloses a device for reinforcing the load-bearing capacity of intersecting steel pipe joints. The device is installed inside the steel pipe joint and includes an air bladder and a positioning part. By inflating the air bladder, the outer wall of the limiting air bladder fits against the inner wall of the steel pipe joint, forming an injection chamber for injecting reinforcing grout at the steel pipe joint with the grouting air bladder. After the injected reinforcing grout solidifies, it can significantly increase the strength and stiffness of the steel pipe joint. At the same time, with the assistance of this device, an annular grouting reinforcement body can be generated, effectively reducing the self-weight of the steel pipe joint reinforcement. Moreover, the device has a simple structure and is easy to operate.

[0031] Furthermore, the wall thickness of the grouting section airbag and the limiting section airbag in this device is 0.3 to 2 mm, and the grouting section airbag and the limiting section airbag are made of rubber material, which has strong strength and can provide effective support for the grouting reinforcement.

[0032] Furthermore, in this device, a spring inside the positioning section causes the connecting plate to rotate, opening the connecting plate and allowing the positioning section to expand inside the steel pipe. This causes the outer wall of the connecting strip connected to the end of the connecting plate to adhere to the inner wall of the steel pipe, positioning the airbag section and the annular grouting reinforcement body to prevent them from moving. This avoids the airbag section moving, which would affect the injection of the reinforcement grout, and the annular grouting reinforcement body moving, which would affect the reinforcement of the steel pipe. Attached Figure Description

[0033] Figure 1 A flowchart of a method for strengthening the load-bearing capacity of intersecting steel pipe joints provided by the present invention;

[0034] Figure 2 The present invention provides a method for strengthening the load-bearing capacity of intersecting steel pipe joints, and a stress cloud diagram of the T-shaped steel pipe joint after strengthening;

[0035] Figure 3 A method for strengthening the load-bearing capacity of intersecting steel pipe joints provided by the present invention is shown in the comparison diagram of the compressive load-displacement curves of the T-shaped steel pipe joint after strengthening and without strengthening.

[0036] Figure 4 The present invention provides a method for strengthening the load-bearing capacity of intersecting steel pipe joints. A tensile stress cloud diagram of the T-shaped steel pipe joint after reinforcement is shown.

[0037] Figure 5 A schematic diagram comparing the tensile load-displacement curves of a reinforced T-shaped steel pipe joint with an unreinforced steel pipe, provided by the present invention, for a method to strengthen the load-bearing capacity of intersecting steel pipe joints.

[0038] Figure 6 This is a structural schematic diagram of a device for reinforcing the load-bearing capacity of intersecting steel pipe nodes provided by the present invention;

[0039] Figure 7 This is a schematic diagram of the positioning part of a device for reinforcing the load-bearing capacity of intersecting steel pipe nodes provided by the present invention.

[0040] Figure 8 This is a schematic diagram of the unopened positioning part of a steel pipe intersection node reinforcement device provided by the present invention;

[0041] Figure 9 This is a bottom view sectional view of the positioning part of the steel pipe intersection node load-bearing capacity reinforcement device provided by the present invention, without being expanded.

[0042] In the attached diagram: 1. Mold inlet; 2. Grouting inlet; 3. Air inlet; 4. Positioning part; 40. Connecting platform; 41. Spring plate; 42. Connecting plate; 43. Rotating column; 44. Connecting shaft; 45. Spring; 5. Air bladder part; 6. Grouting chamber. Detailed Implementation

[0043] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0044] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0048] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0049] See Figure 1 This invention discloses a method for strengthening the load-bearing capacity of intersecting steel pipe joints, which utilizes the aforementioned device and includes the following steps:

[0050] S1. Open the mold inlet and grouting inlet at the steel pipe joint;

[0051] Specifically, the diameter of the branch pipe at the intersection of the steel pipes to be reinforced is measured to obtain the diameter data of the branch pipe. Based on this data, the diameter is increased by 2 to 4 times to obtain the length of the grouting chamber at the intersection of the steel pipe. Based on this length data, the positions of the mold inlet 1 and the grouting port 2 on the outer wall of the steel pipe are determined. Then, the positions of the mold inlet 1 and the grouting port 2 are marked on the main pipe at the intersection of the steel pipe. Then, the mold inlet 1 and the grouting port 2 are opened at the marked positions on the main pipe at the intersection of the steel pipe using an opening tool. The diameter of the mold inlet is less than 2 cm.

[0052] Specifically, the positions of the mold inlet 1 and grouting inlet 2 on the outer wall of the steel pipe are obtained based on the length data. This is achieved by taking the length of the grouting chamber, taking half of the length of the grouting chamber as the positioning data value, and using the position of the corresponding node on the main pipe at the steel pipe node as the zero point. When the steel pipe is installed horizontally, the length of this positioning data value is measured to the left along the length direction of the main pipe to obtain the position of the grouting inlet 2, and the length of this positioning data value is measured to the right along the length direction of the main pipe to obtain the position of the mold inlet 1. When the steel pipe is installed vertically, the length of this positioning data value is measured upwards along the length direction of the main pipe to obtain the position of the grouting inlet 2, and the length of this positioning data value is measured downwards to obtain the position of the mold inlet 1.

[0053] S2. Insert the air bladder into the steel pipe through the mold inlet, inflate the air bladder to saturation, and form an injection chamber at the node inside the steel pipe.

[0054] Specifically, the airbag part 5 is inserted into the steel pipe through the mold inlet 1. The airbag part 5 is located on the side of the positioning part 4 inside the steel pipe, so that the limiting part airbag in the airbag part 5 is located at the position of the steel pipe node, and the center position of the grouting part airbag is aligned with the position of the steel pipe node. During the installation of the airbag part 5, the grouting part airbag with the air port 3 is located below the node inside the steel pipe. That is, after the airbag part 5 is installed, the air port 3 is located at the mold inlet 1 and extends out of the outside of the steel pipe from the mold inlet 1. Then, the airbag part 5 is inflated to saturation through the air port 3 to form an injection chamber 6 at the node inside the steel pipe. The airbag part is made by hot pressing.

[0055] S3. Insert the positioning part into the steel pipe through the mold inlet and place it below the airbag part;

[0056] Specifically, the positioning part 4 is installed inside the steel pipe and placed below the airbag part 5; wherein, when the steel pipe is not installed horizontally, the positioning part 4 expands inside the steel pipe to form a placement platform to support the airbag part 5, and when the steel pipe is installed horizontally, the positioning part 4 expands inside the steel pipe to form a baffle to limit the airbag part 5.

[0057] S4. Inject the reinforcing grout through the grouting port, let it stand to solidify and form a ring-shaped grouting and reinforcing body, and then pull out the positioning part.

[0058] Specifically, the processing slurry is used to seal the mold inlet 1. The reinforcing slurry is slowly injected into the injection chamber 6 from the injection port 2 until the slurry overflows from the injection port 2. The injection port 2 is then sealed and left to stand so that the reinforcing slurry solidifies, forming a ring-shaped grouting and reinforcing body at the node inside the steel pipe. Then the positioning part 4 is pulled out.

[0059] The reinforcing grout is one or more of epoxy resin, graphene-reinforced cement, and cement grout.

[0060] S5. Remove the air bladder and seal the mold inlet and grout injection port.

[0061] Specifically, the air vent 3 on the air bladder is opened to release the air in the limiting air bladder and the grouting air bladder. The air bladder 5 is then removed from the mold inlet 1 and the positioning part 4 is installed from the mold inlet 1 to position the annular grouting solid in the steel pipe. Finally, the mold inlet 1 and the grouting port 2 are sealed.

[0062] If the annular grouting solid adheres to the air bladder section, the gas in the air bladder section 5 is first removed, and an organic solvent capable of dissolving the air bladder section 5 is injected into the air port 3 of the air bladder section 5 to dissolve the air bladder section 5, so that the center of the annular grouting solid is hollow, connecting its two sides and ensuring the connectivity of the steel pipe.

[0063] The organic solvent is acetone.

[0064] The above-mentioned reinforcement method is simple to operate and convenient to use. After reinforcement, the pipes located above and below the reinforcement position can be interconnected, which does not affect the discharge of drilling fluid, exhaust gas and waste liquid during offshore drilling.

[0065] The following explanation and description are provided in conjunction with the embodiments:

[0066] In this embodiment, a main pipe with a wall thickness of 6mm, a length of 1700mm, and a diameter of 180mm is selected. A branch pipe with a diameter of 120mm, a wall thickness of 6mm, and a length of 500mm is selected. The length of the grouting section airbag is selected to be 3 times the diameter of the branch pipe, and the internal channel diameter of the grouting chamber 6 is selected to be 0.7 times the diameter of the steel pipe. That is, the length of the grouting section airbag is 360mm and the diameter is 128mm. The diameter of the limiting section airbag is 168mm, the inner wall diameter of the main pipe, and the length is 100mm. There are two of them, which are placed on both sides of the grouting section airbag. The wall thickness of the grouting section airbag and the limiting section airbag is selected to be 1mm.

[0067] S1. Measure the diameter of the branch pipe at the intersection of the steel pipes to be reinforced as 120mm. Multiply this data by 3 to obtain the length of the grouting chamber 6 at the steel pipe node as 360mm. Mark the position of the grouting port 2 180mm away from the steel pipe node along the length of the main pipe and above the steel pipe node. Mark the position of the mold inlet 1 280mm away from the steel pipe node along the length of the main pipe and below the steel pipe node. Then, use an opening tool to open the mold inlet 1 and the grouting port 2 on the main pipe at the marked positions, and set the diameter of the mold inlet 1 to 2cm.

[0068] S2. The air bladder 5 with a wall thickness of 1mm is inserted into the steel pipe through the mold inlet 1. The air bladder 5 is inflated through the air inlet 3 to open the air bladder 5 above the positioning part 4, forming an injection chamber 6.

[0069] S3. Insert the positioning part 4 into the steel pipe and position it below the airbag part 5, and expand the positioning part 4 to form a placement platform.

[0070] S4. Take the reinforcing grout and seal the mold inlet 1. Slowly inject the cement grout into the injection chamber 6 from the injection port 2 until the grout overflows from the injection port 2. Seal the injection port 2 and then let it stand to allow the reinforcing grout to solidify, forming a ring-shaped cement grouting reinforcement body.

[0071] S5. Open the air port 3 on the air bladder of the grouting part to release the air in the air bladder 5, remove the air bladder 5 from the mold inlet 1, and then seal the mold inlet 1 and the grouting port 2.

[0072] The steel pipe reinforced according to the above embodiments was subjected to ABAQUS simulation test. Figures 2-5 ; Figure 2 This is a stress contour map of the reinforced steel pipe under compressive stress. The load-displacement comparison curve is obtained by comparing the compressive condition shown in this map with that of the unreinforced steel pipe. Figure 3As shown in the figure, the black curve represents the compression condition of the reinforced steel pipe, and the red curve represents the compression curve of the unreinforced steel pipe. It can be seen from the figure that the load borne by the reinforced steel pipe is significantly greater than that of the unreinforced steel pipe, and the strength at the joint of the steel pipe is increased by about 50%.

[0073] Figure 3 The figure shows the stress cloud diagram of the reinforced steel pipe under tension. The black curve represents the tensile condition after reinforcement using this method. A comparison curve is obtained by contrasting the tensile condition of the reinforced steel pipe with that of the unreinforced steel pipe. Figure 4 As shown in the figure, the black dots represent the tensile condition of the reinforced steel pipe, and the red curve represents the tensile condition of the unreinforced steel pipe. It can be seen that the tensile force borne by the reinforced steel pipe is significantly greater than that of the unreinforced steel pipe, and the strength at the joint of the steel pipe is increased by about 15%.

[0074] In summary, this method enhances the load-bearing capacity of intersecting joints by grouting inside the pipe. It is applicable to various types of steel pipe joints, such as T-joints and K-joints. With the assistance of the reinforcement device, a ring-shaped grouting reinforcement can be formed on the inner wall of the pipe. This significantly improves the load-bearing capacity of the joint without affecting the structural appearance or normal functionality, greatly reducing the self-weight of the reinforcement, and enabling underwater operations. The compressive and tensile properties of the steel pipe reinforced by this method are significantly improved. Therefore, this reinforcement method can effectively improve structural performance and reduce structural self-weight.

[0075] See Figure 6 The present invention discloses a device for reinforcing the load-bearing capacity of intersecting steel pipe nodes. The device includes an air bladder 5 and a positioning part 4. The air bladder 5 is installed at the node inside the steel pipe to form an injection chamber 6 for injecting reinforcing slurry. The positioning part 4 is installed inside the steel pipe on the side of the air bladder 5 to support the air bladder 5.

[0076] See Figure 6 The airbag part 5 includes a limiting airbag and a grouting airbag. The two ends of the limiting airbag are connected to the grouting airbag and are also connected to the grouting airbag. One end airbag is provided with an air port, through which air can be inflated into the grouting airbag and the limiting airbag. The wall thickness of the grouting airbag and the limiting airbag is 1 to 3 mm.

[0077] Preferably, the length of the grouting section air bladder is 2 to 4 times the diameter of the branch pipe. During use, because the length of the grouting section air bladder is 2 to 4 times the diameter of the branch pipe, the length of the grouting chamber 6 formed inside the steel pipe is 2 to 4 times the diameter of the steel pipe, and the internal channel diameter of the grouting chamber 6 is 0.5 to 0.7 times the diameter of the steel pipe. This allows the device to form a sufficiently large grouting chamber 6 at the steel pipe joint, ensuring that enough reinforcing grout is injected into the steel pipe and guaranteeing the reinforcement strength at the steel pipe joint.

[0078] Furthermore, the grouting section airbag and the limiting section airbag in this device are made and spliced ​​by one or more of thermoplastic polyurethane elastomer rubber, thermoplastic vulcanized rubber and thermoplastic polyester elastomer through hot pressing molding. The grouting section airbag and the limiting section airbag are cylindrical, which facilitates the use and removal of the device and increases the ease of use of the device.

[0079] See Figures 7-9 The positioning part 4 includes a connecting platform 40, a support plate fixedly connected to the right end face of the connecting platform 40, a mounting hole rotatably provided at the connection between the support plate and the connecting platform 40, a connecting shaft 44 rotatably provided in the mounting hole, one end of a connecting plate 42 rotatably connected to the connecting shaft 44, so that the connecting plate 42 can rotate on the connecting platform 40, a spring 45 is connected to the connecting plate 42 and the support plate at a position away from the connecting platform 40, one end of the spring 45 is fixed to the connecting plate 42 and the other end is fixed to the support plate, when there is no external force between the connecting plate 42 and the support plate, the spring 45 can make the connecting plate 42 and the support plate spread apart into a tree fork shape and be stuck in the inner wall of the main pipe; a rotating column 43 is provided on the connecting platform 40, and a connecting belt 41 is wound on the rotating column 43. One end of the positioning part 4 extends out of the connecting platform 40, passes around the ends of the connecting plate 42 and the support plate, and is then fixed inside the connecting platform 40. After the positioning part 4 is inserted into the steel pipe, the rotating column 43 is released, and the connecting plate 42 will open under the action of the spring 45. At the same time, the connecting plate 42 and the support plate will simultaneously open the connecting band, so that the connecting band 41 is opened into a circle, opening the positioning part 4 inside the steel pipe, allowing the connecting band 41 to fit against the inner wall of the steel pipe, and fixing the positioning part 4 inside the steel pipe. After the reinforcing slurry is injected into the injection chamber 6, the positioning part 4 can provide stable support for the airbag part 5, increasing the stability of the device. At the same time, when the connection between the annular grouting body and the inner wall of the steel pipe is not tight, the positioning part 4 can also play a limiting role, preventing the annular grouting body from moving. In this embodiment, the connecting band 41 is made of elastic steel.

[0080] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0081] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for strengthening the load-bearing capacity of intersecting steel pipe joints, characterized in that, Includes the following steps: S1. On the main pipe near the intersection of steel pipes, an inlet (1) and a grouting port (2) are respectively opened on both sides of the intersection of steel pipes. The diameter of the inlet (1) is less than 2 cm. S2. Insert an airbag (5) into the main pipe through the mold inlet (1). The airbag (5) includes an injection airbag and two limiting airbags connected to both ends of the injection airbag. Align the center position of the injection airbag with the position of the intersection node of the steel pipe, and extend the air port (3) out of the main pipe through the mold inlet (1). Inflate the airbag (5) through the air port (3) so that the two limiting airbags fit against the inner wall of the main pipe. The inner wall of the main pipe, the outer wall of the injection airbag, and the two limiting airbags together define the annular injection chamber (6). The length of the annular injection chamber (6) is 2 to 4 times the diameter of the branch pipe. S3. Insert the positioning part (4) into the main tube through the mold inlet (1) in an unopened state and place it below the airbag part (5); the positioning part (4) includes a connecting platform (40), a support plate is provided on the connecting platform (40), a connecting plate (42) is rotatably connected to the support plate, a spring (45) is connected between the connecting plate (42) and the support plate, a rotating column (43) is rotatably mounted on the connecting platform (40), and one end of the connecting strip (41) is wound around the rotating column (43). The other end of the connecting strap (41) is fixedly connected to the connecting platform (40). The connecting strap (41) passes around the ends of the connecting plate (42) and the support plate, and the connecting strap (41) is made of elastic steel. After the positioning part (4) is inserted into the main tube, the rotating column (43) is released, so that the connecting plate (42) and the support plate are opened under the action of the spring (45), and the connecting strap (41) is driven to unfold to fit against the inner wall of the main tube, so as to support and limit the airbag part (5). S4. Seal the mold inlet (1), inject reinforcing slurry into the annular injection chamber (6) through the grouting port (2) until the reinforcing slurry overflows from the grouting port (2) and then seal the grouting port (2); let it stand until the reinforcing slurry solidifies, forming an annular grouting reinforcement body partially set along the main pipe axis at the intersection node of the steel pipes, and then pull out the positioning part (4). S5. The gas in the airbag (5) is discharged through the air port (3), and the airbag (5) is taken out through the mold inlet (1). The mold inlet (1) and the grouting port (2) are sealed, so that the center of the annular grouting solid forms a through channel communicating with the inner cavity of the main tube on both sides of its axial direction.

2. The method for strengthening the load-bearing capacity of intersecting steel pipe joints according to claim 1, characterized in that, The airbag part (5) is made by hot pressing and splicing.

3. The method for strengthening the load-bearing capacity of intersecting steel pipe joints according to claim 1, characterized in that, The reinforcing slurry in S4 is one or more of epoxy resin, graphene-reinforced cement, and cement slurry.

4. The method for strengthening the load-bearing capacity of intersecting steel pipe joints according to claim 1, characterized in that, If the annular grouting solid adheres to the airbag part (5), after the gas in the airbag part (5) is discharged, an organic solvent is injected into the airbag part (5) through the air port (3) to dissolve the airbag part (5).

5. A device for reinforcing the load-bearing capacity of intersecting steel pipe joints, comprising an airbag part (5) and a positioning part (4), characterized in that: The airbag section (5) includes an injection section airbag and two limiting section airbags respectively connected to both ends of the injection section airbag; after the two limiting section airbags are inflated, they fit against the inner wall of the main pipe, so that the inner wall of the main pipe, the outer wall of the injection section airbag and the two limiting section airbags together define the annular injection chamber (6). The positioning part (4) includes a connecting platform (40), a support plate is provided on the connecting platform (40), a connecting plate (42) is rotatably connected to the support plate, a spring (45) is connected between the connecting plate (42) and the support plate, a rotating column (43) is rotatably mounted on the connecting platform (40), one end of a connecting strip (41) is wound around the rotating column (43), the other end of the connecting strip (41) is fixedly connected to the connecting platform (40), the connecting strip (41) passes around the ends of the connecting plate (42) and the support plate, and the connecting strip (41) is made of elastic steel; The airbag part (5) and the positioning part (4) in the unopened state can be inserted into the main pipe through the mold inlet (1) with a diameter of less than 2 cm on the main pipe; after the rotating column (43) is released, the connecting plate (42) and the supporting plate are opened under the action of the spring (45), and the connecting belt (41) is driven to unfold to fit against the inner wall of the main pipe, so as to support and limit the airbag part (5) during the grouting process.

6. A device for reinforcing the load-bearing capacity of intersecting steel pipe joints according to claim 5, characterized in that, The wall thickness of both the grouting part airbag and the limiting part airbag is 0.3 to 2 mm.

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