Full-self-anchoring flexible connection stainless steel composite steel pipe

Abstract

The invention relates to a full-self-anchoring flexible connection stainless steel composite steel pipe, and belongs to the technical field of full-self-anchoring steel pipes. A self-adaptive dynamic compensation structure is introduced, and when the extrusion stress borne by a rubber ring exceeds a preset threshold value, the structure is in linkage fit with a spring movable part through a sliding part; the axial displacement compensation and the elastic pre-tightening force are cooperated, and the extrusion stress of the rubber ring is dynamically maintained in a reasonable range, so that the sealing effect can be maintained when the rubber ring deforms due to aging or abrasion, the pressure fluctuation caused by heat energy generated by friction between water flow and a pipe wall and environment temperature change can be coped, and the service life of the pipe is prolonged. By means of the design, the situation that the rubber ring bears extrusion stress exceeding a design value due to the fact that internal pressure is increased is avoided, stress concentration and structural fatigue are reduced, the service life of the rubber ring is prolonged, the maintenance cost and the replacement period of a long-distance buried pipeline are reduced, and the vicious circle problem that the service life of an existing structural rubber ring is shortened is effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of fully self-anchored steel pipes, and particularly relates to a fully self-anchored flexible connection stainless steel composite pipe. Background Art

[0002] The fully self-anchored flexible connection stainless steel composite pipes used in long-distance water diversion projects need to meet the special working conditions requirements of resisting uneven settlement of the foundation, earthquake resistance and uplift bearing. Its connection system consists of a butt socket and a socket of a specific shape, as well as a rubber ring and a limit boss between the two. During installation, a reasonable assembly gap is reserved to avoid excessive deformation of the rubber ring.

[0003] However, in actual operation, the superposition of multiple factors leads to the accelerated failure of the sealing system: First, the rubber ring will gradually shrink under the long-term influence of water flow scouring and aging, weakening the initial sealing effect; Second, the continuous friction between the water flow and the pipe wall accumulates energy loss with the increase of distance, and the kinetic energy is converted into heat energy, resulting in a local water temperature rise. At the same time, the change of the ambient temperature causes the thermal expansion and contraction of the water body - when the temperature rises, the water body expands to generate an outward expansion pressure, and when the temperature drops, a negative pressure may be formed. This dynamic pressure fluctuation significantly increases the internal pressure of the pipeline. More severely, the increased internal pressure forces the already shrunk and aged rubber ring to bear a squeezing stress far exceeding the design value, resulting in stress concentration at the sealing interface, accelerating the structural fatigue and permanent deformation of the rubber ring. Moreover, the concealment and construction complexity of long-distance buried pipelines make the operation cost of replacing damaged rubber rings high and the cycle long. Therefore, the rubber rings of the existing structure have a sharply shortened life under the combined action of multiple pressures, and it is urgent to solve this vicious cycle problem by designing a new type of fully self-anchored flexible connection stainless steel composite pipe. Summary of the Invention

[0004] To solve the above problems existing in the prior art, the present invention provides a fully self-anchored flexible connection stainless steel composite pipe, which solves the problems existing in the above background art.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A fully self-anchored flexible connection stainless steel composite pipe includes a plurality of steel pipe bodies and rubber rings. The two ends of the steel pipe body respectively form a socket and a spigot. The rubber ring is hermetically arranged at the joint of the socket and the spigot. Corresponding sliding parts and spring movable parts are arranged on the mating surfaces of the socket end and the spigot end. The sliding part and the spring movable part together form an adaptive dynamic compensation structure. When the rubber ring deforms due to wear or aging, the sliding part and the spring movable part trigger a linkage cooperation based on a preset displacement threshold. Through the coordinated action of axial displacement compensation and elastic pre-tightening force, the squeezing stress borne by the rubber ring is dynamically maintained within a preset threshold range, preventing overload failure caused by squeezing force fluctuations.

[0007] As a further solution of the present invention, the spring movable part includes a positioning seat arranged at the socket end, a first limiting rod axially penetrating through the positioning seat, a movable rod arranged parallel to the first limiting rod, a compression spring connecting the first limiting rod and the movable rod, and a rotary limiting mechanism; the rotary limiting mechanism includes a U-shaped limiting block, one end of the U-shaped limiting block is hinged to the positioning seat through a rotating shaft, and the other end of the U-shaped limiting block forms an arc-shaped protrusion that is clamped with the sliding part; the movable rod drives the U-shaped limiting block to rotate around the rotating shaft under the action of the compression spring, so as to realize the dynamic adjustment of the locking force between the sliding part and the spring movable part.

[0008] As a further solution of the present invention, the sliding part is a sliding block provided with a wedge-shaped guiding surface, a locking groove matching the arc-shaped protrusion is opened on the side wall of the sliding block, and an arc-shaped fitting surface adapted to the side wall contour of the sliding block is provided at one end of the U-shaped limiting block close to the movable rod.

[0009] As a further solution of the present invention, a tapered guiding head is formed by extending the end of the first limiting rod, and the tapered guiding head forms a plug-in fit with a tapered socket groove opened on the side wall of the sliding block, so as to limit the lateral displacement of the sliding block.

[0010] As a further solution of the present invention, the pre-tightening force of the compression spring is positively correlated with the designed internal pressure of the pipeline. When the compression amount of the rubber ring reaches the threshold value, the displacement of the movable rod triggers the rotation of the U-shaped limiting block, so that the arc-shaped protrusion and the locking groove form a progressive lock, realizing the self-balancing of the sealing pressure.

[0011] As a further solution of the present invention, a wavy anti-slip pattern is provided between the wedge-shaped guiding surface of the sliding block and the arc-shaped fitting surface of the U-shaped limiting block.

[0012] As a further solution of the present invention, the rubber ring adopts a multi-layer composite structure, including an outer wear-resistant rubber layer, an intermediate nano-enhanced layer and an inner elastic compensation layer.

[0013] As a further solution of the present invention, the positioning seat adopts a detachable mounting structure. A dovetail groove is provided at the bottom of the positioning seat, a dovetail guide rail is provided at the socket end, the dovetail groove is slidably matched with the dovetail guide rail provided at the socket end, and is fixed by a locking bolt.

[0014] As a further solution of the present invention, an auxiliary sealing structure is further provided at the connection between the socket and the spigot. The auxiliary sealing structure includes an annular sealing groove and a water-swellable water stop strip filled therein.

[0015] The beneficial effects of the present invention are as follows:

[0016] By introducing an adaptive dynamic compensation structure, the problem of shrinkage of rubber rings caused by long-term water flow scouring and aging is effectively solved. When the extrusion stress borne by the rubber ring exceeds the preset threshold, through the linkage cooperation between the sliding part and the spring movable part, the synergy of axial displacement compensation and elastic pre-tightening force is realized, and the extrusion stress of the rubber ring is dynamically maintained within a reasonable range. In this way, not only can the sealing effect be maintained when the rubber ring deforms due to aging or wear, but also the pressure fluctuations caused by the heat energy generated by the friction between the water flow and the pipe wall and the environmental temperature change can be coped with. This design avoids the extrusion stress exceeding the design value borne by the rubber ring due to the increase of internal pressure, thereby reducing stress concentration and structural fatigue, prolonging the service life of the rubber ring, and reducing the maintenance cost and replacement cycle of long-distance buried pipelines, effectively solving the vicious cycle problem of the shortened service life of rubber rings in the existing structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] For the convenience of those skilled in the art to understand, the present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 is a state diagram of the initial installation of the rubber ring of the present invention;

[0020] Figure 3 is a state diagram of the rubber ring of the present invention deformed due to wear or aging;

[0021] Figure 4 For the present invention Figure 2 is an enlarged view of part A in the present invention.

[0022] Description of the main component symbols:

[0023] In the figure: 1, steel pipe body; 2, boss; 3, circular snap ring; 4, hook head; 5, socket; 6, spigot; 7, rubber ring; 8, sliding part; 81, sliding block; 82, locking groove; 83, tapered slot; 9, spring movable part; 91, positioning seat; 92, first limiting rod; 93, movable rod; 94, compression spring; 95, rotary limiting mechanism. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will describe in detail the specific embodiments, structures, features and effects of the present invention with reference to the accompanying drawings and preferred embodiments.

[0025] Please refer to Figure 1 - Figure 4, this embodiment provides a fully self-anchored flexible connection stainless steel composite steel pipe, which includes a plurality of steel pipe bodies 1 and rubber rings 7. At both ends of the steel pipe body 1, a socket 5 and a spigot 6 are respectively formed. The rubber ring 7 is sealingly arranged at the joint of the socket 5 and the spigot 6. A sliding part 8 and a spring movable part 9 are correspondingly arranged on the mating surfaces of the socket 5 end and the spigot 6 end. The sliding part 8 and the spring movable part 9 together constitute an adaptive dynamic compensation structure. When the rubber ring 7 deforms due to wear or aging, the sliding part 8 and the spring movable part 9 trigger a linkage cooperation based on a preset displacement threshold. Through the synergistic action of axial displacement compensation and elastic pre-tightening force, the extrusion stress borne by the rubber ring 7 is dynamically maintained within a preset threshold range, preventing overload failure caused by extrusion force fluctuations. Among them, in addition to the socket 5, the spigot 6 and the rubber ring 7 at the existing butt-jointed pipe interface, there are also a circular snap ring 3, a hook 4 and a boss 2. During installation, only need to install the sealing rubber ring on the spigot 6, insert the spigot 6 into the socket 5, and then push the circular snap ring 3 between the boss 2 and the hook 4. Through the radial expansion and rebound deformation of the circular snap ring 3, it expands and adheres inside the hook 4, and the installation can be completed. Here, it will not be elaborated much, as Figure 1 shown.

[0026] At present, the fully self-anchored flexible connection stainless steel composite steel pipes used in long-distance water diversion projects need to meet the special working condition requirements of resisting uneven settlement of the foundation, earthquake resistance and uplift bearing. Its connection system consists of a butt-jointed spigot 6, a socket 5 with a specific shape, and a rubber ring 7 and a limit boss 2 between them. During installation, a reasonable assembly gap is reserved to avoid excessive deformation of the rubber ring 7. However, in actual operation, the superposition of multiple factors leads to the accelerated failure of the sealing system: First, the rubber ring 7 will gradually shrink under the long-term influence of water flow scouring and aging, weakening the initial sealing effect; Second, the continuous friction between the water flow and the pipe wall accumulates energy loss with the increase of distance, and the kinetic energy is converted into heat energy, resulting in a local water temperature rise. At the same time, the environmental temperature change causes the thermal expansion and contraction of the water body - when the temperature rises, the water body expands and generates an outward expansion pressure, and when the temperature drops, a negative pressure may be formed. This dynamic pressure fluctuation significantly increases the internal pressure of the pipeline. More severely, the increased internal pressure forces the already shrunk and aged rubber ring 7 to bear an extrusion stress far exceeding the design value, resulting in stress concentration at the sealing interface and accelerating the structural fatigue and permanent deformation of the rubber ring 7. Moreover, the concealment and construction complexity of long-distance buried pipelines make the operation cost of replacing the damaged rubber ring 7 high and the cycle long. Therefore, the service life of the rubber ring 7 with the existing structure is sharply shortened under the combined action of multiple pressures.

[0027] In the above context, to solve the above problems, in this embodiment, by introducing an adaptive dynamic compensation structure, the shrinkage problem of the rubber ring 7 caused by long-term water flow scouring and aging is effectively solved. When the extrusion stress borne by the rubber ring 7 exceeds the preset threshold, through the linkage cooperation between the sliding part 8 and the spring movable part 9, the axial displacement compensation and the elastic pre-tightening force act synergistically to dynamically maintain the extrusion stress of the rubber ring 7 within a reasonable range. In this way, not only can the sealing effect be maintained when the rubber ring 7 deforms due to aging or wear, but also the pressure fluctuations caused by the heat energy generated by the friction between the water flow and the pipe wall and the environmental temperature change can be coped with. This design avoids the extrusion stress borne by the rubber ring 7 exceeding the design value due to the increase in internal pressure, thereby reducing stress concentration and structural fatigue, extending the service life of the rubber ring 7, and reducing the maintenance cost and replacement cycle of long-distance buried pipelines, effectively solving the vicious cycle problem of the shortened service life of the rubber ring 7 in the existing structure.

[0028] In order to better avoid the internal pressure fluctuation forcing the rubber ring 7 to bear the stress exceeding the design stress and resulting in fatigue failure, in one embodiment, the spring movable part 9 includes a positioning seat 91 arranged at the socket 6 end, a first limiting rod 92 axially passing through the positioning seat 91, a movable rod 93 arranged parallel to the first limiting rod 92, a compression spring 94 connecting the first limiting rod 92 and the movable rod 93, and a rotary limiting mechanism 95; the rotary limiting mechanism 95 includes a U-shaped limiting block, one end of the U-shaped limiting block is hinged to the positioning seat 91 through a rotating shaft, and the other end of the U-shaped limiting block forms an arc-shaped protrusion that is engaged with the sliding part 8; the movable rod 93 drives the U-shaped limiting block to rotate around the rotating shaft under the action of the compression spring 94 to realize the dynamic adjustment of the locking force between the sliding part 8 and the spring movable part 9. The spring movable part 9 is designed with the pre-tightening force of the compression spring 94 being positively correlated with the internal pressure of the pipeline. When the internal pressure increases, the spring pre-tightening force synchronously increases, pushing the U-shaped limiting block to rotate and lock the sliding block 81, forming a progressive pressure balance to avoid overload caused by pressure mutation and realizing the self-adjustment of the sealing pressure.

[0029] Since the pipelines in long-distance water diversion projects may vibrate due to factors such as water flow impact, pump operation, earthquake or wind force, these vibrations will continuously act on the screw connections, causing the screws to gradually loosen, thereby affecting the locking effect. To avoid this problem, in one embodiment, the sliding part 8 is a sliding block 81 provided with a wedge-shaped guiding surface. A locking groove 82 matching the arc-shaped protrusion is opened on the side wall of the sliding block 81. One end of the U-shaped limiting block close to the movable rod 93 is provided with an arc-shaped fitting surface adapted to the side wall contour of the sliding block 81. The wedge-shaped guiding surface and the arc-shaped protrusion form geometric self-locking, and cooperate with the conical slot 83 to limit the lateral displacement, ensuring that the compensation action is accurate and controllable. Due to the adoption of the arc-shaped fitting surface and the locking groove 82, even in the case of wear, the locking function of the system will not degenerate, thus ensuring the stability of long-term use.

[0030] In addition, in long-distance water diversion projects, the internal pressure of the pipeline may change due to various factors such as terrain and climate, and the internal structure of the pipeline is more likely to become unstable. In this regard, in one embodiment, the end of the first limiting rod 92 extends to form a conical guide head, and the conical guide head forms a plug-in fit with the conical slot 83 opened on the side wall of the sliding block 81, which is used to limit the lateral displacement of the sliding block 81, effectively restricting the lateral displacement of the sliding block 81 in the pipeline and ensuring the stability of the internal structure of the pipeline. The pre-tightening force of the compression spring 94 is positively correlated with the designed internal pressure of the pipeline. When the compression amount of the rubber ring 7 reaches the threshold, the displacement of the movable rod 93 triggers the rotation of the U-shaped limiting block, causing the arc-shaped protrusion to form a progressive locking with the locking groove 82, realizing the self-balancing of the sealing pressure, enabling the sealing pressure to automatically adjust according to the change of the internal pressure of the pipeline, avoiding poor sealing or over-compression caused by internal pressure fluctuations, ensuring the self-balancing of the sealing pressure through the progressive locking mechanism, improving the sealing performance, and effectively preventing water resource leakage.

[0031] Continuing with the above embodiment, during long-distance water diversion, due to the scouring action of the water flow, the friction between the sliding block 81 and the U-shaped limiting block may decrease, resulting in a slipping phenomenon when the sliding block 81 slides in the U-shaped limiting block, and the long-term sliding friction may cause wear on the surfaces of the sliding block 81 and the U-shaped limiting block, thereby affecting their normal operation and sealing effect. In this regard, in one embodiment, there are wavy anti-slip lines between the wedge-shaped guide surface of the sliding block 81 and the arc-shaped fitting surface of the U-shaped limiting block. The wavy anti-slip lines can increase the friction between the sliding block 81 and the U-shaped limiting block, reduce the wear rate, and reduce the slipping phenomenon, ensuring the stability and safety of the water diversion project.

[0032] During actual use, in long-distance water diversion projects, the rubber ring 7 needs to withstand the long-term action of various external factors such as water pressure, water flow scouring, and chemical corrosion, and is prone to wear and aging, resulting in a decline in sealing performance. In this regard, in one embodiment, the rubber ring 7 adopts a multi-layer composite structure, including an outer wear-resistant rubber layer, a middle nano-enhanced layer, and an inner elastic compensation layer. The outer wear-resistant rubber layer can effectively resist water flow scouring and chemical corrosion, improving the durability of the rubber ring 7. The middle nano-enhanced layer enhances the mechanical strength and durability of the rubber ring 7, and the inner elastic compensation layer ensures that the rubber ring 7 can still maintain good elasticity and sealing performance when compressed. This design can extend the service life of the rubber ring 7, reduce the frequency of maintenance and replacement, and lower the operating cost of long-distance water diversion projects.

[0033] Furthermore, in long-distance water diversion projects, it is necessary to regularly inspect and maintain components such as springs or limit blocks. Since the maintenance of long-distance water diversion projects themselves is difficult, in order to make maintenance relatively simple and reduce maintenance costs and time, in one embodiment, the positioning seat 91 adopts a detachable installation structure, a dovetail groove is provided at the bottom of the positioning seat 91, and a dovetail guide rail is provided at the end of the socket 6. The dovetail groove and the dovetail guide rail provided at the end of the socket 6 are slidably matched and fixed by a locking bolt. The dovetail groove guide rail and the locking bolt realize the rapid disassembly and assembly of the positioning seat 91, which is convenient for on-site replacement of springs or limit blocks; the sliding match between the dovetail groove and the dovetail guide rail, combined with the locking bolt, realizes rapid disassembly and assembly, which is convenient for on-site replacement of springs or limit blocks, improves maintenance efficiency, simplifies maintenance procedures, and improves the reliability and economy of the project.

[0034] In addition, in order to provide better backup sealing measures to avoid leakage and affect the normal operation of the project, in one embodiment, an auxiliary sealing structure is also provided at the connection between the socket 5 and the plug 6, and the auxiliary sealing structure includes an annular sealing groove and a water-swelling waterstop strip filled therein. When the rubber ring 7 fails, there is a lack of backup sealing, which is easy to cause leakage accidents. The water-swelling material is pre-placed in the annular sealing groove as an emergency sealing layer. The water-swelling waterstop strip in the annular sealing groove can provide additional sealing effect when the rubber ring 7 fails, thereby enhancing the safety and reliability of the system, providing additional protection for possible leakage, and reducing potential problems.

[0035] The working principle and use process of the present invention:

[0036] The present invention introduces an adaptive dynamic compensation structure. When the rubber ring 7 shrinks due to aging or internal pressure fluctuations, resulting in a change in compression, the sliding portion 8 and the spring movable portion 9 trigger linkage based on a preset displacement threshold value. The spring preload force drives the U-shaped limit block to rotate, driving the sliding block 81 to move axially, and fills the sealing gap caused by rubber contraction in real time. The accuracy and stability of the compensation action are ensured by the conical slot 83 and the wavy anti-slip pattern, so that the extrusion stress of the rubber ring 7 is always dynamically maintained within the safety threshold, avoiding stress concentration and overload caused by gap expansion or pressure mutation. Failure, the spring preload is positively correlated with the internal pressure of the pipeline. When the temperature rises or the water flow impact causes the internal pressure to increase, the spring automatically increases the locking force to balance the expansion pressure; when the temperature drops to form a negative pressure, the elastic preload relieves the stretching of the rubber ring 7 to prevent the interface from detaching, thereby effectively responding to the periodic impact of thermal expansion and contraction and dynamic loads. At the same time, the design of the tapered guide head and the tapered slot 83 further limits the lateral displacement of the sliding block 81 to ensure that the compensation action is only performed in the axial direction to prevent structural dislocation. The wavy anti-slip pattern increases the friction of the sliding surface to avoid accidental loosening due to vibration.

[0037] As described above, these are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above in the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments of equivalent changes within the scope of the technical solution of the present invention by using the technical content disclosed above. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A fully self-anchored flexible connection stainless steel composite steel pipe, characterized in that: The utility model comprises a plurality of steel pipe bodies and rubber rings, wherein two ends of the steel pipe body respectively form a socket and a plug, the rubber ring is sealingly arranged at the joint of the socket and the plug, and a sliding part and a spring movable part are correspondingly arranged on the mating surfaces of the socket end and the plug end, and the sliding part and the spring movable part constitute an adaptive dynamic compensation structure. When the rubber ring is deformed due to wear or aging, the sliding part and the spring movable part trigger linkage cooperation based on a preset displacement threshold value, and through the synergistic effect of axial displacement compensation and elastic preload force, the extrusion stress borne by the rubber ring is dynamically maintained within the preset threshold range, thereby preventing overload failure caused by extrusion pressure fluctuation.

2. The fully self-anchored flexible connection stainless steel composite steel pipe according to claim 1, characterized in that: The spring movable part includes a positioning seat arranged at the socket end, a first limiting rod axially inserted through the positioning seat, a movable rod arranged parallel to the first limiting rod, a compression spring connecting the first limiting rod and the movable rod, and a rotating limiting mechanism; the rotating limiting mechanism includes a U-shaped limiting block, one end of the U-shaped limiting block is hinged to the positioning seat through a rotating shaft, and the other end of the U-shaped limiting block forms an arc-shaped protrusion engaged with the sliding part; the movable rod drives the U-shaped limiting block to rotate around the rotating shaft under the action of the compression spring, thereby realizing dynamic adjustment of the locking force of the sliding part and the spring movable part.

3. The fully self-anchored flexible connection stainless steel composite steel pipe according to claim 2, characterized in that: The sliding part is a sliding block with a wedge-shaped guide surface, the side wall of the sliding block is provided with a locking groove matching the arc-shaped protrusion, and the end of the U-shaped limit block close to the movable rod is provided with an arc-shaped fitting surface adapted to the contour of the side wall of the sliding block.

4. The fully self-anchored flexible connection stainless steel composite steel pipe according to claim 2, characterized in that: The end of the first limiting rod extends to form a conical guide head, and the conical guide head is plug-fitted with a conical slot provided on the side wall of the sliding block to limit the lateral displacement of the sliding block.

5. The fully self-anchored flexible connection stainless steel composite steel pipe according to claim 3, characterized in that: The preload force of the compression spring is positively correlated with the designed internal pressure of the pipeline. When the compression of the rubber ring reaches a threshold, the displacement of the movable rod triggers the rotation of the U-shaped limit block, so that the arc-shaped protrusion and the locking groove form a progressive locking, thereby achieving self-balancing of the sealing pressure.

6. The fully self-anchored flexible connection stainless steel composite steel pipe according to claim 3, characterized in that: A wavy anti-slip pattern is provided between the wedge-shaped guiding surface of the sliding block and the arc-shaped fitting surface of the U-shaped limiting block.

7. The fully self-anchored flexible connection stainless steel composite steel pipe according to claim 1, characterized in that: The rubber ring adopts a multi-layer composite structure, including an outer wear-resistant rubber layer, a middle nano-reinforced layer and an inner elastic compensation layer.

8. The fully self-anchored flexible connection stainless steel composite steel pipe according to claim 2, characterized in that: The positioning seat adopts a detachable installation structure, a dovetail groove is provided at the bottom of the positioning seat, a dovetail guide rail is provided at the socket end, the dovetail groove and the dovetail guide rail provided at the socket end are slidably matched and fixed by a locking bolt.

9. The fully self-anchored flexible connection stainless steel composite steel pipe according to claim 1, characterized in that: An auxiliary sealing structure is also provided at the connection between the socket and the plug, and the auxiliary sealing structure includes an annular sealing groove and a water-swelling water stop strip filled therein.

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