Prestressed concrete pipe pile rotary embedded anti-retreat locking connecting joint and assembling method

Abstract

This invention discloses a rotation-embedded locking connection node and assembly method for prestressed concrete pipe piles, belonging to the technical field of pipe pile connection nodes. It includes a first locking part, a second locking part, and several limiting blocks, respectively fixed to the ends of two pipe pile sections. The two sets of locking parts are centrally symmetrically arranged, each equipped with an array of L-shaped connectors. The length of the long rod section of the second L-shaped connector matches the sum of the length of the long rod section of the first L-shaped connector and the circumferential width of the limiting blocks. During assembly, the two sets of locking parts are rotated circumferentially into each other along the guide groove, relying on the mutual abutment of the extended sections of the L-shaped connectors to achieve axial locking and restrict axial dislocation of the pipe pile. After engagement, a locking groove is formed, and a metal adhesive is applied to the groove and a limiting block is embedded to prevent the locking parts from rotating in the opposite direction, achieving circumferential anti-rotation and anti-loosening. This invention combines mechanical locking and adhesive curing for dual anti-loosening effects, is easy to assemble, requires no on-site welding, has excellent structural rigidity and pull-out and torsional resistance, and can be adapted to various specifications of prestressed pipe pile construction conditions.

Description

Technical Field

[0001] This invention relates to the field of construction technology for prestressed concrete pipe pile connection nodes, and in particular to a rotation-embedded locking connection node and assembly method for prestressed concrete pipe piles. It is applicable to the rapid splicing and locking construction of precast prestressed concrete pipe pile segments in engineering projects such as building pile foundations, geotechnical support, and bridge foundations. Background Technology

[0002] Prestressed concrete pipe piles (PHC pipe piles) are widely used in building pile foundations, municipal engineering, bridge support, and large-scale geotechnical foundation engineering due to their advantages such as high bearing capacity, good integrity, fast construction speed, and strong durability. During pipe pile construction, the length of a single pipe pile section is limited, requiring multiple sections to be spliced ​​together. Therefore, the structural performance, assembly accuracy, and construction reliability of the connection nodes between pile sections directly determine the overall bearing capacity and service stability of the pile foundation.

[0003] Currently, the mainstream splicing methods for prestressed concrete pipe piles in China are end plate welding connection, mechanical bolt connection, and core-filled anchorage connection. Among them, traditional end plate welding connection involves a large amount of on-site welding work, and the welding quality is greatly affected by human and environmental factors. The weld is prone to defects such as slag inclusion, porosity, corrosion and cracking. Under long-term vertical loads and reciprocating vibration, weld failure and joint separation are likely to occur. In addition, the welding construction efficiency is low and there are safety hazards from open flame operations. Conventional mechanical bolt connection requires matching the precise end plate hole position, which is cumbersome. The bolts are prone to loosening and corrosion under long-term stress, resulting in circumferential movement of the pile segment and a decrease in axial pull-out performance. Core-filled anchorage connection has a long curing period, cannot meet the needs of rapid assembly construction, and is difficult to adapt to high-efficiency pile foundation construction scenarios.

[0004] Existing mechanical interlocking connection nodes for pipe piles mostly adopt a single toothed meshing locking structure, which generally suffers from stress coupling defects. Axial bearing capacity and circumferential anti-rotation function are mutually constrained, and can only achieve simple axial limiting. They cannot effectively resist torsional loads and reciprocating vibrations during the service of the pile foundation, and are prone to reverse loosening and disengagement. At the same time, most connection nodes have complex structures and low assembly fault tolerance, which cannot meet the splicing requirements of high precision, high bearing capacity and high stability of prestressed pipe piles, and it is difficult to balance construction efficiency and long-term service safety performance.

[0005] Therefore, there is an urgent need for a rotary embedded locking connection node and assembly method that features clear force zoning, convenient assembly, excellent load-bearing performance, and strong anti-loosening stability, in order to solve many shortcomings of the existing technology. Summary of the Invention

[0006] The purpose of this invention is to provide a rotating embedded locking connection node and assembly method for prestressed concrete pipe piles, which enables rapid alignment and engagement of the concrete pipe section ends, axial rigid locking, and circumferential anti-rotation and anti-loosening, thus solving the technical problems of traditional joints such as dislocation, loosening, poor durability, and low construction efficiency.

[0007] To achieve the above objectives, the present invention provides a prestressed concrete pipe pile rotation-embedded anti-reverse locking connection node, disposed at the ends of a first pipe section and a second pipe section, including a first engaging part, a second engaging part, and several limiting blocks. The first engaging part is fixedly installed at the end of the first pipe section, and the second engaging part is fixedly installed at the end of the second pipe section. The first engaging part and the second engaging part are centrally symmetrically arranged. The first engaging part and the second engaging part form an engaging fit, and the groove formed by their fit is a guide groove. The first engaging part and the second engaging part rotate relative to each other circumferentially along the guide groove, and simultaneously screw into each other axially to achieve mutual locking. After the first and second engaging parts are engaged, they form locking grooves on one side of the circumferential direction of the engaging parts, with the same number of locking grooves as the engaging parts. The limiting block is embedded in the locking groove to prevent reverse circumferential rotation between the first and second engaging parts.

[0008] Preferably, the first engaging part includes a first connecting end plate and a first L-shaped connector. A plurality of first L-shaped connectors are arranged in a circumferential annular array on the end face of the first connecting end plate away from the pipe section. The first L-shaped connector is divided into a long rod section and a short rod section. The end of the short rod section away from the long rod section extends a fixed distance toward the long rod section to form an extension section. The extension section is parallel to the long rod section. The second engaging portion includes a second connecting end plate and a second L-shaped connector. Several second L-shaped connectors are arranged in a circumferential array on the end face of the second connecting end plate away from the pipe section. The second L-shaped connectors are divided into a long rod section and a short rod section. The end of the short rod section away from the long rod section extends a fixed distance toward the long rod section to form an extension section, which is parallel to the long rod section. The extension section of the first L-shaped connector in the first engaging portion can abut against the short rod section along the guide groove with the extension section of the corresponding second L-shaped connector in the second engaging portion, thereby achieving axial locking of the pipe section.

[0009] Preferably, both the first and second engaging parts are metal engaging components, and both are fixed to the corresponding pipe section ends by pre-embedded anchoring.

[0010] Preferably, a first through hole is formed at the center of the first engaging part along the axial direction, and a second through hole is formed at the center of the second engaging part along the axial direction; after the first engaging part and the second engaging part are screwed into and locked in place, the openings of the first through hole and the second through hole are completely aligned vertically, and their axes coincide to form a continuous coaxial through channel.

[0011] Preferably, the limiting block is a rectangular pin that is adapted to the locking groove, and the two are fitted with a clearance. After the limiting block is inserted into place, the outer end face is flush with or lower than the outer peripheral surface of the connecting node, and the inner wall of the locking groove is coated with metal adhesive.

[0012] Preferably, the effective axial engagement length of the first L-shaped connector and the second L-shaped connector is 30mm to 40mm, and the solid thickness of the first L-shaped connector and the second L-shaped connector is 60mm to 70mm.

[0013] The above-mentioned assembly method for the rotating embedded locking connection node of prestressed concrete pipe pile includes the following steps: S1. Alignment and pre-assembly: The first pipe segment to be connected and the second pipe segment are placed coaxially opposite each other. The circumferential angle of the two pipe segments is adjusted so that the guide grooves in the middle of each L-shaped connector on the outer periphery of the end of the first pipe segment correspond one by one and the gaps are aligned, forming an assembly position that can be screwed in and engaged. At this time, the two sets of L-shaped connectors are staggered to ensure that there is circumferential rotation assembly allowance. S2, Circumferential screwing in: Keep the first pipe section and the second pipe section in an axially fitted state, apply a circumferential rotational force to the first pipe section or the second pipe section, so that the first locking part and the second locking part rotate relative to each other. During the rotation, the first L-shaped connector extension of the first locking part and the second L-shaped connector extension of the second locking part gradually overlap, bite and abut against each other. S3. Apply adhesive: After the axial engagement is in place, a locking groove is formed between the first engagement part and the second engagement part. Metal adhesive is evenly applied inside the locking groove beforehand. Then, the limiting block is inserted into the locking groove after the adhesive is applied. The limiting block adheres to the adhesive layer and simultaneously abuts against the circumferential stop surface of the upper and lower L-shaped connectors. S4. Complete overall assembly and locking: After assembly, the L-shaped connector can bear most of the axial separation load and achieve high-strength axial anti-disengagement limit; the limit block is embedded in the locking groove and undertakes the circumferential anti-rotation limit function, blocking the opposite relative rotation of the first engagement part and the second engagement part, preventing the structure from loosening and disengaging under vibration and external load disturbance, so that the two pipe sections form a fully constrained rigid integral docking structure.

[0014] Therefore, the present invention, employing the above-mentioned prestressed concrete pipe pile rotation embedding anti-reverse locking connection node and assembly method, has the following technical effects: (1) The present invention adopts an axial and circumferential force-dispersing structure. The axial tensile and anti-dislocation main load is borne by the overlapping and interlocking of the extension section of the L-shaped connector, and the circumferential anti-rotation constraint is borne by the limiting block. This avoids the problem of local stress concentration and easy failure caused by the force coupling of the traditional structure, and the overall load-bearing stability of the joint is greatly improved.

[0015] (2) The present invention is convenient and efficient to assemble and has good workability. The present invention only requires three steps to complete the assembly: alignment, screwing in the interlocking, and applying adhesive to install the limiting block. It does not require on-site pouring or a large number of bolts for fastening. The assembly speed is fast and it is suitable for batch assembly construction of precast concrete pipes.

[0016] (3) The present invention has a dual anti-loosening structure with high service reliability. A metal adhesive curing structure is added at the assembly position of the limiting block, which, combined with the mechanical rigid limiting, forms a dual anti-loosening system of "mechanical locking + adhesive curing", which can effectively resist long-term vibration and alternating loads in engineering projects and prevent the limiting block from slipping and the joint from unscrewing and disengaging.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the split structure of the two sets of engaging parts of the prestressed concrete pipe pile rotation embedding anti-reverse locking connection node of the present invention; Figure 2 This is a schematic diagram of the tight alignment state of the engaging part of the prestressed concrete pipe pile rotation embedding anti-reverse locking connection node of the present invention; Figure 3 This is a schematic diagram of the interlocking state of the L-shaped connectors at the prestressed concrete pipe pile rotation embedding anti-reverse locking connection node of the present invention; Figure 4 This is a schematic diagram showing the completed embedding state of the limiting block of the prestressed concrete pipe pile rotation embedding anti-reverse locking connection node of the present invention.

[0019] Figure Labels 1. First engaging part; 11. First connecting end plate; 12. First L-shaped connector; 2. Second engaging part; 21. Second connecting end plate; 22. Second L-shaped connector; 3. First through hole; 4. Second through hole; 5. Locking groove; 6. Limiting block; 7. Guide groove. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] Example 1 like Figures 1 to 4 As shown, this embodiment discloses a prestressed concrete pipe pile rotation embedding anti-reverse locking connection node, which is used for quick splicing and locking of the ends of two prestressed concrete pipe piles. The device is installed at the end of the prestressed concrete pipe section and includes a first locking part 1, a second locking part 2 and several limiting blocks 6 that are matched. The first locking part 1 is pre-embedded in the end of the first pipe section and the second locking part 2 is pre-embedded in the end of the second pipe section. The first locking part 1 and the second locking part 2 are arranged in a centrally symmetrical manner to ensure accurate structural alignment and uniform stress during the rotation docking process.

[0023] The first engaging part 1 consists of a first connecting end plate 11 and a plurality of first L-shaped connectors 12. The first connecting end plate 11 is a metal annular end plate structure, which is fixed to the end face of the first pipe section by pre-embedded anchoring. On the end face of the first connecting end plate 11 away from the pipe section, a plurality of sets of first L-shaped connectors 12 are evenly arranged in a circular array along the circumference. Correspondingly, the second engaging part 2 consists of a second connecting end plate 21 and a plurality of second L-shaped connectors 22. The second connecting end plate 21 is also fixed to the end face of the second pipe section by pre-embedded anchoring. On the end face of the second connecting end plate 21 away from the pipe section, a circular array of second L-shaped connectors 22 is arranged, the number of which is exactly matched with the number of first L-shaped connectors 12. The first engaging part 1 and the second engaging part 2 are both integrally formed, which can effectively transmit the axial tensile force, compressive force and local torsional load of the pipe pile, and are suitable for the high load-bearing conditions of prestressed concrete pipe piles.

[0024] The center of the first engaging part 1 is provided with a first through hole 3 along the axial direction, and the center of the second engaging part 2 is provided with a second through hole 4 along the axial direction. When the first engaging part 1 and the second engaging part 2 are screwed into the engaging and locked in place, the openings of the first through hole 3 and the second through hole 4 are precisely aligned and their axes are completely coincident, forming a coaxial through channel that runs through the entire connection node.

[0025] The first L-shaped connector 12 and the second L-shaped connector 22 are structurally matched, each including an integrally formed long rod segment and a short rod segment, which are perpendicular to each other to form an L-shaped structure. The free end of the short rod segment away from the long rod segment extends a predetermined fixed distance towards the long rod segment to form an extension segment. The extension segment is parallel to the long rod segment, ensuring the flatness and engagement stability of the structure. Before assembly, the two sets of engaging parts form matching guide grooves 7. During assembly, the first engaging part 1 and the second engaging part 2 rotate relative to each other circumferentially along the opposing guide grooves 7, simultaneously completing axial screw-in engagement and achieving rotational embedded assembly. The length of the long rod segment of the second L-shaped connector 22 is equal to the sum of the length of the long rod segment of the first L-shaped connector 12 and the circumferential width of the limiting block 6. This dimensional matching relationship ensures that after the two sets of connectors rotate and engage, they can accurately form a locking groove 5 suitable for the installation of the limiting block 6, ensuring precise assembly and locking of the limiting block 6.

[0026] The extension section of the first L-shaped connector 12 abuts against the extension section of the corresponding second L-shaped connector 22, and the extension section abuts against the inner side of the short rod section of the paired L-shaped connector. The rigid abutment action of the extension section restricts the axial separation displacement of the two pipe piles, thereby achieving axial locking bearing of the pipe pile connection node. In this embodiment, the effective axial engagement length of the L-shaped connector is preferably 30mm to 40mm, and the solid thickness of the L-shaped connector is preferably 60mm to 70mm. This parameter range can ensure sufficient axial engagement bearing area and structural rigidity of the component, effectively avoiding the problems of insufficient pull-out bearing capacity due to excessive engagement length and compressive deformation due to thin component thickness, thus ensuring the overall bearing performance of the connection node. At the same time, this parameter can be adaptively adjusted according to the pipe pile diameter and engineering design load, and is not limited to the numerical range specified in this embodiment.

[0027] After the first engaging part 1 and the second engaging part 2 are fully engaged and locked in place, the circumferential sides of the two sets of engaging parts form locking grooves 5 that correspond one-to-one with the number of L-shaped connectors. Each locking groove 5 is regularly positioned and uniform in size, and is used to embed and fix the limiting block 6. In this embodiment, the limiting block 6 adopts a rectangular pin key structure that matches the shape of the locking groove 5. The limiting block 6 and the locking groove 5 adopt a clearance fit, which facilitates quick assembly and embedding on site. After the limiting block 6 is fully inserted into place, its outer end face is flush with or slightly lower than the outer circumferential surface of the connecting node, without any protruding structure, to avoid the problem of scraping, bumping and falling off during the pile foundation driving construction, which is suitable for the pipe pile driving construction conditions.

[0028] To further enhance the anti-loosening and anti-detachment performance of the limiting block 6, a layer of metal adhesive is uniformly applied to the inner wall of the locking groove 5 before the limiting block 6 is assembled, and then the limiting block 6 is embedded. After the adhesive cures, the limiting block 6 is bonded and fixed to the inner wall of the locking groove 5, forming a dual anti-loosening system with the mechanical clamping structure. This effectively resists vibration loads and torsional loads during the long-term service of the pile foundation, preventing the limiting block 6 from loosening or slipping. After the limiting block 6 is assembled, it can rigidly block the reverse circumferential rotation between the first engaging part 1 and the second engaging part 2, completely locking the circumferential degree of freedom of the node, preventing the L-shaped connector from unscrewing and disengaging, and completing the overall locking of the node.

[0029] This invention also discloses a method for assembling a prestressed concrete pipe pile rotation embedding anti-reverse locking connection node, comprising the following steps: S1. Alignment and pre-assembly: The first pipe segment to be connected and the second pipe segment are placed coaxially opposite each other. The circumferential angle of the two pipe segments is adjusted so that the guide grooves 7 in the middle of each L-shaped connector on the outer periphery of the end of the first pipe segment and each L-shaped connector on the outer periphery of the end of the second pipe segment correspond one-to-one and the gaps are aligned to form an assembly position that can be screwed in and engaged. At this time, the two sets of L-shaped connectors are staggered to ensure that there is circumferential rotation assembly allowance. S2, Circumferential Screwing: Maintaining the axial fit of the first and second pipe sections, apply a circumferential rotational force to the first or second pipe section, causing the first engaging part 1 and the second engaging part 2 to rotate relative to each other. During the rotation, the extension of the first L-shaped connector 12 of the first engaging part 1 and the extension of the second L-shaped connector 22 of the second engaging part 2 gradually overlap and bite each other. When the assembly is completed, the extensions of the L-shaped connectors on both sides completely overlap and bite each other, forming a rigid axial limit by relying on the contact surface of the extensions, restricting the axial separation displacement of the two concrete pipe sections, and completing the axial anti-disengagement locking of the joint. At this time, the joint has axial tensile and anti-disengagement capabilities, but the two concrete pipe sections can still rotate circumferentially in opposite directions, posing a risk of disengagement, and are in a pre-locked state.

[0030] S3. Apply adhesive: After the axial engagement is in place, a locking groove 5 is formed between the first engagement part 1 and the second engagement part 2. Metal adhesive is evenly applied inside the locking groove 5 beforehand. Then, the limiting block 6 is inserted into the locked groove 5 after the adhesive is applied. The limiting block 6 adheres to the adhesive layer and simultaneously abuts against the circumferential stop surface of the upper and lower L-shaped connectors. S4. Complete overall assembly and locking: After assembly, the L-shaped connector can bear most of the axial separation load and achieve high-strength axial anti-disengagement limit; the limit block 6 is embedded in the locking groove 5 and undertakes the circumferential anti-rotation limit function, blocking the opposite relative rotation of the first locking part 1 and the second locking part 2, preventing the structure from loosening and disengaging under vibration and external load disturbance, so that the two pipe sections form a completely constrained rigid overall docking structure.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A prestressed concrete pipe pile rotation-embedded anti-reverse locking connection node, located at the end of the first pipe section and the end of the second pipe section, characterized in that: It includes a first engaging part, a second engaging part, and several limiting blocks. The first engaging part is fixedly installed at the end of a first pipe section, and the second engaging part is fixedly installed at the end of a second pipe section. The first engaging part and the second engaging part are arranged in a centrally symmetrical manner. The first engaging part and the second engaging part form an engaging fit, and the groove formed by the two parts is a guide groove. The first engaging part and the second engaging part rotate relative to each other in the circumferential direction along the guide groove, and simultaneously screw into each other in the axial direction to achieve mutual locking. After the first and second engaging parts are engaged, they form locking grooves on one side of the circumferential direction of the engaging parts, with the same number of locking grooves as the engaging parts. The limiting block is embedded in the locking groove to prevent reverse circumferential rotation between the first and second engaging parts.

2. The prestressed concrete pipe pile rotation embedding anti-reverse locking connection node according to claim 1, characterized in that: The first engaging part includes a first connecting end plate and a first L-shaped connector. A plurality of first L-shaped connectors are arranged in a circumferential ring array on the end face of the first connecting end plate away from the pipe section. The first L-shaped connector is divided into a long rod section and a short rod section. The end of the short rod section away from the long rod section extends a fixed distance toward the long rod section to form an extension section. The extension section is parallel to the long rod section. The second engaging portion includes a second connecting end plate and a second L-shaped connector. Several second L-shaped connectors are arranged in a circumferential array on the end face of the second connecting end plate away from the pipe section. The second L-shaped connectors are divided into a long rod section and a short rod section. The end of the short rod section away from the long rod section extends a fixed distance toward the long rod section to form an extension section, which is parallel to the long rod section. The extension section of the first L-shaped connector in the first engaging portion can abut against the short rod section along the guide groove with the extension section of the corresponding second L-shaped connector in the second engaging portion, thereby achieving axial locking of the pipe section.

3. The prestressed concrete pipe pile rotation embedding anti-reverse locking connection node according to claim 2, characterized in that: Both the first and second locking parts are metal locking components, and both are fixed to the corresponding pipe section ends by pre-embedded anchoring.

4. The prestressed concrete pipe pile rotation embedding anti-reverse locking connection node according to claim 3, characterized in that: The center of the first engaging part has a first through hole along the axial direction, and the center of the second engaging part has a second through hole along the axial direction. After the first engaging part and the second engaging part are screwed into place and locked in place, the openings of the first through hole and the second through hole are completely aligned vertically, and their axes coincide to form a continuous coaxial through channel.

5. The prestressed concrete pipe pile rotation embedding anti-reverse locking connection node according to claim 4, characterized in that: The limiting block is a rectangular pin that is adapted to the locking groove. The two are fitted with a clearance. After the limiting block is inserted into place, its outer end face is flush with or lower than the outer peripheral surface of the connecting node. The inner wall of the locking groove is coated with metal adhesive.

6. The prestressed concrete pipe pile rotation embedding anti-reverse locking connection node according to claim 5, characterized in that: The effective axial engagement length of the first L-shaped connector and the second L-shaped connector is 30mm to 40mm, and the solid thickness of the first L-shaped connector and the second L-shaped connector is 60mm to 70mm.

7. An assembly method for a prestressed concrete pipe pile rotation-embedded locking connection node, based on the prestressed concrete pipe pile rotation-embedded locking connection node as described in claim 6, characterized in that, Includes the following steps: S1. Alignment and pre-assembly: The first pipe segment to be connected and the second pipe segment are placed coaxially opposite each other. The circumferential angle of the two pipe segments is adjusted so that the guide grooves in the middle of each L-shaped connector on the outer periphery of the end of the first pipe segment correspond one by one and the gaps are aligned, forming a screw-in and snap-fit ​​assembly position. At this time, the two sets of L-shaped connectors are staggered to ensure that there is circumferential rotation assembly allowance. S2, Circumferential screwing in: Keep the first pipe section and the second pipe section in an axially fitted state, apply a circumferential rotational force to the first pipe section or the second pipe section, so that the first locking part and the second locking part rotate relative to each other. During the rotation, the first L-shaped connector extension of the first locking part and the second L-shaped connector extension of the second locking part gradually overlap, bite and abut against each other. S3. Apply adhesive: After the axial engagement is in place, a locking groove is formed between the first engagement part and the second engagement part. Metal adhesive is evenly applied inside the locking groove beforehand. Then, the limiting block is inserted into the locking groove after the adhesive is applied. The limiting block adheres to the adhesive layer and simultaneously abuts against the circumferential stop surface of the upper and lower L-shaped connectors. S4. Complete overall assembly and locking: After assembly, the L-shaped connector bears most of the axial separation load, achieving high-strength axial anti-disengagement limit; the limit block is embedded in the locking groove, which plays the role of circumferential anti-rotation limit, blocking the opposite relative rotation of the first engagement part and the second engagement part, preventing the structure from loosening and disengaging under vibration and external load disturbance, so that the two pipe sections form a fully constrained rigid integral docking structure.

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