A simulation device and test method for secondary stress of buried pipelines after repair

Abstract

The present invention relates to the technical field of performance testing of buried pipelines, and particularly relates to a device and test method for simulating secondary stress on a buried pipeline after repair. A device for simulating secondary stress on a buried pipeline after repair includes: a loading frame, the loading frame includes an upper loading plate and a lower bearing plate, the upper loading plate and the lower bearing plate are correspondingly arranged, a pipeline to be tested is adapted to be accommodated between the upper loading plate and the lower bearing plate, a lining is adapted to be accommodated in the pipeline to be tested, the inner wall of the pipeline to be tested is attached to the outer wall of the lining, and vertical rods are arranged between the upper loading plate and the lower bearing plate; along the direction of the vertical rods, the upper loading plate and the lower bearing plate approach or move away from each other; a loading assembly for driving the upper loading plate and the lower bearing plate to approach; a monitoring assembly including a data acquisition box for acquiring vertical loads and the strain and deformation of the pipeline to be tested. The present invention solves the problem that the test device cannot explore the stress and bearing characteristics of the pipeline-lining system under secondary stress.

Description

Technical Field

[0001] The present invention relates to the technical field of buried pipeline performance testing, and particularly relates to a device and test method for simulating secondary stress of a buried pipeline after repair. Background Art

[0002] Buried pipelines are severely damaged and aged. At present, the most commonly used repair method is the trenchless repair technology. The trenchless repair technology forms a closely fitting lining pipe in the existing pipeline through spraying, insertion or light curing, etc., so as to achieve the purpose of repairing and strengthening the existing pipeline. At present, the main test method for evaluating the bearing performance of the existing pipeline-lining system after repair is the external pressure load test method recommended by GB / T 16752-2006. However, when using the trenchless repair technology to repair and strengthen the existing pipeline, the existing pipeline has already been subjected to the action of pre-loads such as soil pressure load and surface load before the lining is applied. The lining after application only starts to cooperate with the existing pipeline in bearing force under the action of later loads (or when further deformation occurs due to the reduction of the structural strength of the existing pipeline). The existing pipeline after repair belongs to a secondary stress structure, rather than the primary stress structure described in the external pressure load test method. Therefore, it is difficult to accurately restore the stress condition of the existing pipeline after repair in the actual working condition by using the existing external pressure load test device and test method, and it is impossible to explore the influence of secondary stress on the stress characteristics and bearing characteristics of the existing pipeline-lining system. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the existing test device cannot explore the influence of secondary stress on the stress characteristics and bearing characteristics of the existing pipeline-lining system, so as to provide a device and test method for simulating secondary stress of a buried pipeline after repair.

[0004] To solve the above problems, the present invention provides a device for simulating secondary stress of a buried pipeline after repair, including:

[0005] A loading frame, the loading frame includes an upper loading plate and a lower bearing plate, the upper loading plate and the lower bearing plate are correspondingly arranged, a pipeline to be tested is adapted to be accommodated between the upper loading plate and the lower bearing plate, a lining is adapted to be accommodated in the pipeline to be tested, the inner wall of the pipeline to be tested is in close contact with the outer wall of the lining, and vertical rods are arranged between the upper loading plate and the lower bearing plate; along the direction of the vertical rods, the upper loading plate and the lower bearing plate approach or move away from each other;

[0006] A loading component for driving the upper loading plate and the lower bearing plate to approach;

[0007] A monitoring component, including a data acquisition box, the data acquisition box is used for acquiring vertical load and the strain and deformation of the pipeline to be tested.

[0008] Optionally, the loading component includes: a loading oil cylinder disposed above the upper loading plate to drive the upper loading plate to move downward relative to the lower bearing plate.

[0009] Optionally, the upper loading plate and the lower bearing plate are of a polygonal structure, and first through holes are provided at the corresponding corner points of the upper loading plate and the lower bearing plate. Vertical rods are inserted through the first through holes, and the loading components are arranged in one-to-one correspondence with the vertical rods. The loading component further includes an upper cushion block and a lower cushion block, and second through holes are respectively provided on the upper cushion block and the lower cushion block. The bottom of the lower cushion block contacts the upper surface of the upper loading plate.

[0010] Optionally, a convex end is provided on the surface of the upper cushion block facing the lower cushion block, and a groove is provided on the surface of the lower cushion block facing the upper cushion block, and the convex end is adapted to the groove.

[0011] Optionally, a receiving space is formed between the upper cushion block and the lower cushion block, and a first locking nut is provided in the receiving space, and the first locking nut is threadedly connected to the vertical rod.

[0012] Optionally, the upper surface of the upper cushion block contacts the bottom of the loading oil cylinder, and a second locking nut is provided at one end of the loading oil cylinder facing away from the upper cushion block, and the second locking nut is threadedly connected to the vertical rod.

[0013] Optionally, a steel beam is provided between the pipeline to be tested and the upper loading plate, and a support component is provided between the pipeline to be tested and the lower bearing plate.

[0014] Optionally, a backing plate is provided between the steel beam and the pipeline to be tested, and a pressure sensor is provided between the steel beam and the upper loading plate.

[0015] Optionally, the support component includes two support members, a support cross bar and a fastener. The support members are adapted to fit against the outer wall of the pipeline to be tested, and the support cross bar passes through the support members and is locked by the fastener.

[0016] Optionally, a fixed sleeve is further included, and the fixed sleeve is sleeved on the outer periphery of the vertical rod, and the fixed sleeve is fixedly connected to the lower bearing plate.

[0017] Optionally, rib plates are equiangularly arranged on the outer surface of the fixed sleeve, and a central hole is left at the center position of the fixed sleeve.

[0018] Optionally, the loading component further includes a loading pump, and the loading pump is connected to the loading oil cylinder through a hydraulic pipeline. The loading oil cylinder is of a hollow structure, and the vertical rod passes through the hollow structure.

[0019] Optionally, it further includes a tubular fixing bracket, the central axis of the fixing bracket coincides with the central axis of the pipeline to be tested, strain sensors are arranged at equal angles in the circumferential direction along the inner wall and the outer wall of the pipeline to be tested, and displacement sensors are arranged on the fixing bracket.

[0020] Optionally, the data acquisition box is respectively connected to the pressure sensor, the strain sensor and the displacement sensor through data transmission lines.

[0021] A test method for a secondary stress simulation device of a buried pipeline after repair. In the test state, the loading assembly drives the upper loading plate to move towards the lower bearing plate in a step-by-step loading manner until the pipeline to be tested ruptures and fails. The loading oil cylinder maintains the load, repairs and reinforces the pipeline to be tested to form a lining, and the loading oil cylinder continues to load until the pipeline-lining system to be tested is completely damaged, so as to obtain the ultimate bearing capacity under the secondary stress condition of the system.

[0022] Optionally, it includes the following steps:

[0023] S1. Start the loading pump, and the loading oil cylinder loads the pipeline to be tested step by step through the upper loading plate until the vertical load applied reaches the test preset value.

[0024] S2. Tighten the first locking nut to restrict the upper loading plate from moving away from the lower bearing plate, so that the vertical load is maintained at the test preset value.

[0025] S3. Repair and reinforce the pipeline to be tested under the test preset load and cure it for a specified time to form a lining, and the lining is closely attached to the inner wall of the pipeline to be tested.

[0026] S4. Start the loading pump, and the loading oil cylinder continues to load the pipeline-lining system to be tested step by step through the upper loading plate until the pipeline-lining system to be tested is completely damaged, so as to obtain the ultimate bearing capacity under the secondary stress condition of the system.

[0027] The technical solution of the present invention has the following advantages:

[0028] 1. The secondary stress simulation device for buried pipelines after repair provided by the present invention includes: a loading frame, which includes an upper loading plate and a lower bearing plate. The upper loading plate and the lower bearing plate are correspondingly arranged. The space between the upper loading plate and the lower bearing plate is suitable for accommodating the pipeline to be tested. The pipeline to be tested is suitable for accommodating a lining. The inner wall of the pipeline to be tested is in contact with the outer wall of the lining. There are vertical rods between the upper loading plate and the lower bearing plate; along the direction of the vertical rods, the upper loading plate and the lower bearing plate move closer to or away from each other; a loading assembly for driving the upper loading plate and the lower bearing plate to move closer to or away from each other; a monitoring assembly, including a data acquisition box, which is used for acquiring the vertical load as well as the strain and deformation of the pipeline to be tested. In the test state, the loading assembly drives the upper loading plate to move towards the lower bearing plate in a step-by-step loading manner until the pipeline to be tested fails. The loading oil cylinder maintains the load, repairs and strengthens the pipeline to be tested to form a lining, and the loading oil cylinder continues to load until the pipeline-lining system is completely damaged, so as to obtain the ultimate bearing capacity of the system under the condition of secondary stress. By applying load, maintaining load and reloading to the pipeline to be tested through the loading assembly, the secondary stress state of the buried pipeline after repair and strengthening is truly simulated, making it possible to explore the influence of secondary stress on the mechanical properties of the pipeline-lining system.

[0029] 2. In the secondary stress simulation device for buried pipelines after repair provided by the present invention, the loading assembly includes a loading oil cylinder, which is arranged above the upper loading plate to drive the upper loading plate to move downward relative to the lower bearing plate. The loading oil cylinder applies pressure to the upper loading plate to apply a vertical load to the pipeline to be tested through the upper loading plate.

[0030] 3. In the secondary stress simulation device for buried pipelines after repair provided by the present invention, the upper loading plate and the lower bearing plate are of a polygonal structure. First through holes are provided at the corresponding corner points of the upper loading plate and the lower bearing plate. The vertical rods pass through the first through holes. The loading assemblies are arranged in one-to-one correspondence with the vertical rods. The loading assembly further includes an upper cushion block and a lower cushion block. Second through holes are respectively provided on the upper cushion block and the lower cushion block. The bottom of the lower cushion block is in contact with the upper surface of the upper loading plate. Through the setting of the upper cushion block and the lower cushion block, a space is provided for accommodating the first locking nut.

[0031] 4. In the secondary stress simulation device for buried pipelines after repair provided by the present invention, a raised end is provided on the surface of the upper cushion block facing the lower cushion block, and a groove is provided on the surface of the lower cushion block facing the upper cushion block. The raised end is adapted to the groove. Through the adaptation of the raised end and the groove, it is convenient for the installation and disassembly of the upper cushion block and the lower cushion block.

[0032] 5. The secondary stress simulation device for buried pipelines after repair provided by the present invention forms a receiving space between the upper cushion block and the lower cushion block. A first locking nut is arranged in the receiving space, and the first locking nut is threadedly connected with the vertical rod. When the load needs to be maintained after the loading pump finishes loading, the first locking nut contacts the lower cushion block to limit the upward movement of the upper loading plate away from the lower bearing plate through the first locking nut, thereby keeping the applied vertical load unchanged.

[0033] 6. The secondary stress simulation device for buried pipelines after repair provided by the present invention, the upper surface of the upper cushion block contacts the bottom of the loading oil cylinder. A second locking nut is arranged at one end of the loading oil cylinder away from the upper cushion block, and the second locking nut is threadedly connected with the vertical rod, and then provides a support reaction force for the loading oil cylinder through the second locking nut.

[0034] 7. The secondary stress simulation device for buried pipelines after repair provided by the present invention, a steel beam is arranged between the pipeline to be tested and the upper loading plate, and a support assembly is arranged between the pipeline to be tested and the lower bearing plate. The steel beam is used to transfer the load from the upper loading plate to the pipeline to be tested, avoiding line contact between the pipeline to be tested and the upper loading plate. The support assembly is used to support the pipeline to be tested, avoiding line contact between the pipeline to be tested and the lower bearing plate.

[0035] 8. The secondary stress simulation device for buried pipelines after repair provided by the present invention, a cushion plate is arranged between the steel beam and the pipeline to be tested to avoid direct contact between the steel beam and the pipeline to be tested. A pressure sensor is arranged between the steel beam and the upper loading plate, which is used to monitor the vertical load borne by the pipeline to be tested.

[0036] 9. The secondary stress simulation device for buried pipelines after repair provided by the present invention, the support assembly includes two support members, a support cross bar and a fastener. The support members are adapted to fit the outer wall of the pipeline to be tested. The support cross bar passes through the support members and is locked by the fastener to prevent the support assembly from shifting during the installation process of the pipeline to be tested.

[0037] 10. The secondary stress simulation device for buried pipelines after repair provided by the present invention further includes a fixed sleeve. The fixed sleeve is sleeved on the vertical rod, and the fixed sleeve is fixedly connected with the lower bearing plate. Rib plates are arranged at equal angles on the outer periphery of the fixed sleeve, and a central hole is left at the central position of the fixed sleeve. The setting of the fixed sleeve can effectively increase the stability of the loading frame.

[0038] 11. The secondary stress simulation device for buried pipelines after repair provided by the present invention, the loading assembly further includes a loading pump. The loading pump is connected with the loading oil cylinder through a hydraulic pipeline. The loading oil cylinder is a hollow structure, and the hollow structure is sleeved on the vertical rod. The loading pump provides hydraulic power for the loading oil cylinder. The loading assembly can be reused for multiple sets of loading frames during the load holding stage after loading, which is convenient for carrying out multiple groups of tests simultaneously to shorten the test cycle.

[0039] 12. The secondary stress simulation device for buried pipeline after repair provided by the present invention further includes a fixed bracket. The central axis of the fixed bracket coincides with the central axis of the pipeline to be tested. Strain sensors are arranged at equal angles in the circumferential direction of the inner wall and the outer wall of the pipeline to be tested. Displacement sensors are arranged on the fixed bracket. The strain sensors are used to monitor the strain of the inner wall and the outer wall of the pipeline to be tested, and the displacement sensors are used to monitor the deformation of the pipeline to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 is a schematic structural diagram of the secondary stress simulation device for buried pipeline after repair provided in the embodiments of the present invention;

[0042] Figure 2 is a top view of the upper loading plate provided in the embodiments of the present invention;

[0043] Figure 3 is a top view of the fixed sleeve provided in the embodiments of the present invention;

[0044] Figure 4 is a schematic structural diagram of the upper cushion block and the lower cushion block provided in the embodiments of the present invention;

[0045] Figure 5 is a schematic structural diagram of the secondary stress simulation device for buried pipeline after repair provided in the embodiments of the present invention before installing the loading pump;

[0046] Figure 6 is a schematic structural diagram of the secondary stress simulation device for buried pipeline after repair provided in the embodiments of the present invention after the first loading;

[0047] Figure 7 is a schematic structural diagram of the pipeline - lining after being damaged provided in the embodiments of the present invention;

[0048] Figure 8 is the loading curve adopted by the secondary stress simulation test method for buried pipeline after repair provided in the embodiments of the present invention.

[0049] Description of the reference numerals: 1. upper loading plate; 101. steel plate; 102. rib; 103. first through hole; 104. bolt hole; 2. vertical rod; 3. fixed sleeve; 301. sleeve bottom plate; 302. rib plate; 303. central hole; 4. lower bearing plate; 5. support member; 6. hollow loop structure; 601. upper cushion block; 602. lower cushion block; 603. convex end; 604. groove; 605. second through hole; 7. first locking nut; 8. fastening bolt; 9. locking washer; 10. oil cylinder gasket; 11. second locking nut; 12. loading pump; 13. loading oil cylinder; 14. hydraulic pipeline; 15. data acquisition box; 16. PC terminal; 17. steel beam; 18. backing plate; 19. strain inductor; 20. displacement inductor; 21. pressure inductor; 22. fixed bracket; 23. support cross bar; 24. fastener; 25. base; 26. fixing nut; 27. data transmission line; 28. pipeline to be tested; 29. pipeline after failure; 30. inner lining. Detailed implementation manners

[0050] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0051] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0052] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0053] As Figure 1 shown in FIGS. -8, a detailed implementation manner of a buried pipeline secondary stress simulation device after repair includes: a loading frame and four groups of loading components.

[0054] As Figure 1 , Figure 5 and Figure 6 shown, the loading frame includes a correspondingly arranged upper loading plate 1 and a lower bearing plate 4, and the space between the upper loading plate 1 and the lower bearing plate 4 is suitable for accommodating the pipeline 28 to be tested. As Figure 1 , Figure 2As shown, the upper loading plate 1 and the lower bearing plate 4 are both rectangular in shape. At the corner points of the upper loading plate 1 and the lower bearing plate 4, there are first through holes 103. A vertical rod 2 passes through the first through holes 103, and among them, the lower bearing plate 4 is arranged on the base 25. Specifically, the vertical rod 2 is a high-strength lead screw. As Figure 2 shown, the upper loading plate 1 includes a steel plate 101 and reinforcing ribs 102. At the corner points of the upper loading plate 1, there are first through holes 103. Eight bolt holes 104 are equiangularly arranged in the circumferential direction of the first through holes 103, and the vertical rod 2 passes through the first through holes 103. As Figure 1 , Figure 5 shown, at the corner points of the lower bearing plate 4, there are first through holes 103. Eight bolt holes are equiangularly arranged in the circumferential direction of the first through holes 103. To enhance the structural stability of the loading frame, as Figure 3 , Figure 5 shown, the loading frame further includes four fixed sleeves 3. The fixed sleeves 3 are arranged in one-to-one correspondence with the vertical rods 2. A central hole 303 is left at the central position of the fixed sleeve 3, and the fixed sleeve 3 is sleeved on the vertical rod 2 through the central hole 303. The fixed sleeve 3 is fixed to the lower bearing plate 4 by bolts. As Figure 3 shown, the fixed sleeve 3 is equiangularly provided with four rib plates 302 and a sleeve bottom plate 301 in the circumferential direction. The rib plates 302 are welded to the sleeve bottom plate 301. As Figure 1 , Figure 5 shown, the vertical rod 2 is fixed to the lower bearing plate 4 by a fixing nut 26 and a lock washer 9.

[0055] As Figure 1 , Figure 5 and Figure 6 shown, a steel beam 17 is provided between the upper loading plate 1 and the pipeline 28 to be tested. The steel beam 17 is equal in length to the pipeline 28 to be tested. A pressure sensor 21 is provided between the steel beam 17 and the upper loading plate 1. A cushion plate 18 is provided between the steel beam 17 and the pipeline 28 to be tested. The outer surface of the cushion plate 18 is adapted to the outer wall of the pipeline 28 to be tested. Specifically, the cushion plate 18 is made of rubber. As Figure 1 , Figure 5 and Figure 6 shown, a support assembly is provided between the lower bearing plate 4 and the pipeline 28 to be tested. The support assembly includes two support members 5, three support crossbars 23 and a number of fasteners 24. The support members 5 are in contact with the outer wall of the pipeline 28 to be tested. The support crossbars 23 pass through the support members 5 and are limited by the fasteners 24. The central axis of the support crossbars 23 is perpendicular to the central axis of the pipeline 28 to be tested. Specifically, the support members 5 are steel beams with rounded corners, the support crossbars 23 are connecting screws, and the fasteners 24 are limit nuts.

[0056] As Figure 1 , Figure 5As shown, the loading components are provided in one-to-one correspondence with the vertical rods 2. The loading components include a loading pump 12 and a loading oil cylinder 13 connected by a hydraulic pipeline 14. Among them, the loading oil cylinder 13 is a hollow structure, and the vertical rod 2 is inserted into the hollow structure. The loading pump 12 is arranged on one side of the loading frame. Specifically, the loading oil cylinder 13 is a hydraulic cylinder and the loading pump 12 is a hydraulic pump. As Figure 1 shown, an upper cushion block 601 and a lower cushion block 602 are arranged between the loading oil cylinder 13 and the upper loading plate 1. The upper cushion block 601 and the lower cushion block 602 are assembled to form a hollow rectangular structure 6. The lower cushion block 602 is fixed to the upper loading plate 1 through a fastening bolt 8 and a lock washer 9. Among them, the fastening bolt 8 is threadedly connected to the bolt hole 104. As Figure 1 、 Figure 4 shown, the upper cushion block 601 and the lower cushion block 602 are respectively provided with second through holes 605, and the vertical rod 2 is inserted into the second through holes 605. As Figure 4 shown, a convex end 603 is arranged on the surface of the upper cushion block 601 facing the lower cushion block 602, and a groove 604 is arranged on the surface of the lower cushion block 602 facing the upper cushion block 601. The convex end 603 is adapted to the groove 604. An accommodation space is formed between the upper cushion block 601 and the lower cushion block 602, and a first lock nut 7 is arranged in the accommodation space. The first lock nut 7 is threadedly connected to the vertical rod 2. As Figure 1 shown, a second lock nut 11 is arranged at one end of the loading oil cylinder 13 away from the upper cushion block 601. The second lock nut 11 is threadedly connected to the vertical rod 2 and an oil cylinder gasket 10 is arranged between the second lock nut 11 and the loading oil cylinder 13.

[0057] To facilitate the measurement of the deformation of the pipeline to be tested 28, a fixed support 22 is further arranged in the pipeline to be tested 28. The central axis of the fixed support 22 coincides with the central axis of the pipeline to be tested 28. Eight displacement sensors 20 are arranged at equal angles on the fixed support 22. Eight strain sensors 19 are respectively arranged at equal angles along the circumferential direction of the inner wall and the outer wall of the pipeline to be tested 28. As Figure 1 、 Figure 5 shown, the monitoring components include a data acquisition box 15 and a PC terminal 16. Among them, the data acquisition box 15 is respectively connected to the PC terminal 16, a pressure sensor 21, a strain sensor 19, and a displacement sensor 20 through a data transmission line 27.

[0058] A test method for a buried pipeline post-repair secondary stress simulation device includes the following steps:

[0059] S1. Start the loading pump 12, and the loading oil cylinder 13 gradually loads the pipeline to be tested 28 through the upper loading plate 1 until the applied vertical load reaches the test preset value;

[0060] S2. Tighten the first lock nut 7 to restrict the movement of the upper loading plate 1 in the direction away from the lower bearing plate 4, so that the vertical load is maintained at the test preset value;

[0061] S3. Repair and reinforce the pipeline 28 to be tested under the preset test load, and cure it for a specified time to form the lining 30, and the lining 30 is closely attached to the inner wall of the pipeline 28 to be tested;

[0062] S4. Start the loading pump 12, and the loading oil cylinder 13 continues to load the pipeline 28 - lining 30 system to be tested step by step through the upper loading plate 1 until the pipeline 28 - lining 30 system to be tested is completely damaged, that is, the damaged pipeline 29 and the lining 30 as shown are obtained to obtain the ultimate bearing capacity of the system under the condition of secondary stress. Figure 7 Shown damaged pipeline 29 and lining 30 to obtain the ultimate bearing capacity of the system under the condition of secondary stress.

[0063] As an alternative implementation manner, the loading frame can also be several groups, and the number of loading components is four groups. That is, after the loading components finish loading one group of loading frames, the loading oil cylinder 13 is disassembled and used to load another group of loading frames, which is convenient for carrying out multiple groups of tests simultaneously to shorten the test cycle.

[0064] As an alternative implementation manner, the number of support crossbars can also be 4, 5 or even more.

[0065] As an alternative implementation manner, the shapes of the upper loading plate 1 and the lower bearing plate 4 can also be other shapes such as pentagons.

[0066] Obviously, the above embodiments are only examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. Test method for a secondary stress simulation device of a buried pipeline after repair, characterized in that, it includes: Several groups of loading frames, the loading frames include an upper loading plate (1) and a lower bearing plate (4), the upper loading plate (1) and the lower bearing plate (4) are arranged correspondingly, a pipeline to be tested (28) is adapted to be accommodated between the upper loading plate (1) and the lower bearing plate (4), a lining (30) is adapted to be accommodated in the pipeline to be tested (28), the inner wall of the pipeline to be tested (28) is attached to the outer wall of the lining (30), and vertical rods (2) are arranged between the upper loading plate (1) and the lower bearing plate (4); along the direction of the vertical rods (2), the upper loading plate (1) and the lower bearing plate (4) approach or move away from each other; A loading assembly for driving the upper loading plate (1) and the lower bearing plate (4) to approach; A monitoring assembly, including a data acquisition box (15), the data acquisition box (15) is used to collect vertical loads and the strain and deformation of the pipeline to be tested (28); The loading assembly includes: a loading oil cylinder (13), the loading oil cylinder (13) is arranged above the upper loading plate (1) to drive the upper loading plate (1) to move downward relative to the lower bearing plate (4); The upper loading plate (1) and the lower bearing plate (4) are of a polygonal structure, first through holes (103) are provided at the corresponding corner points of the upper loading plate (1) and the lower bearing plate (4), the vertical rods (2) pass through the first through holes (103), the loading assembly is arranged in one-to-one correspondence with the vertical rods (2), the loading assembly further includes an upper cushion block (601) and a lower cushion block (602), second through holes (605) are respectively provided on the upper cushion block (601) and the lower cushion block (602), and the bottom of the lower cushion block (602) is in contact with the upper surface of the upper loading plate (1); An accommodating space is formed between the upper cushion block (601) and the lower cushion block (602), a first locking nut (7) is arranged in the accommodating space, and the first locking nut (7) is threadedly connected with the vertical rod (2); In the test state, the loading assembly drives the upper loading plate (1) to move towards the lower bearing plate (4) in a step-by-step loading manner until the pipeline to be tested (28) fails due to rupture, the loading oil cylinder (13) maintains the load, repairs and strengthens the pipeline to be tested (28) to form a lining (30), and the loading oil cylinder (13) continues to load until the pipeline to be tested (28)-lining (30) system is completely damaged, so as to obtain the ultimate bearing capacity of the system under the condition of secondary stress.

2. The test method for a secondary stress simulation device of a buried pipeline after repair according to claim 1, characterized in that, A raised end (603) is provided on the surface of the upper cushion block (601) facing the lower cushion block (602), and a groove (604) is provided on the surface of the lower cushion block (602) facing the upper cushion block (601), and the raised end (603) is adapted to the groove (604).

3. The test method for a secondary stress simulation device of a buried pipeline after repair according to claim 2, characterized in that, The upper surface of the upper cushion block (601) is in contact with the bottom of the loading oil cylinder (13). One end of the loading oil cylinder (13) facing away from the upper cushion block (601) is provided with a second locking nut (11), and the second locking nut (11) is threadedly connected to the vertical rod (2).

4. The test method of the secondary stress simulation device for the repaired buried pipeline according to claim 1, characterized in that, A steel beam (17) is provided between the pipeline to be tested (28) and the upper loading plate (1), and a support assembly is provided between the pipeline to be tested (28) and the lower bearing plate (4).

5. The test method of the secondary stress simulation device for the repaired buried pipeline according to claim 4, characterized in that, A backing plate (18) is provided between the steel beam (17) and the pipeline to be tested (28), and a pressure sensor (21) is provided between the steel beam (17) and the upper loading plate (1).

6. The test method of the secondary stress simulation device for the repaired buried pipeline according to claim 4, characterized in that, The support assembly includes two support members (5), a support cross bar (23) and a fastener (24). The support member (5) is adapted to fit against the outer wall of the pipeline to be tested (28), and the support cross bar (23) passes through the support member (5) and is locked by the fastener (24).

7. The test method of the secondary stress simulation device for the repaired buried pipeline according to any one of claims 1-6, characterized in that, It further includes a fixed sleeve (3). The fixed sleeve (3) is sleeved on the vertical rod (2), and the fixed sleeve (3) is fixedly connected to the lower bearing plate (4).

8. The test method of the secondary stress simulation device for the repaired buried pipeline according to claim 7, characterized in that, The outer surface of the fixed sleeve (3) is provided with rib plates (302) at equal angles, and a central hole (303) is left at the central position of the fixed sleeve (3).

9. The test method of the secondary stress simulation device for the repaired buried pipeline according to claim 8, characterized in that, The loading assembly further includes a loading pump (12). The loading pump (12) is connected to the loading oil cylinder (13) through a hydraulic pipeline (14). The loading oil cylinder (13) is a hollow structure, and the hollow structure is sleeved on the outer periphery of the vertical rod (2).

10. The test method of the secondary stress simulation device for the repaired buried pipeline according to claim 9, characterized in that, It further includes a tubular fixed bracket (22). The central axis of the fixed bracket (22) coincides with the central axis of the pipeline to be tested (28). Strain sensors (19) are arranged at equal angular intervals along the circumferential directions of the inner wall and the outer wall of the pipeline to be tested (28), and displacement sensors (20) are arranged on the fixed bracket (22).

11. The test method of the secondary stress simulation device for the repaired buried pipeline according to claim 10, characterized in that, The data acquisition box (15) is respectively connected to the pressure sensor (21), the strain sensor (19), and the displacement sensor (20) through data transmission lines (27).

12. Test method for the buried pipeline repair secondary stress simulation device according to claim 11, characterized in that, it includes the following steps: S1. Start the loading pump (12), and the loading cylinder (13) gradually loads the pipeline to be tested (28) through the upper loading plate (1) until the vertical load applied reaches the test preset value; S2. Tighten the first locking nut (7) to restrict the movement of the upper loading plate (1) in the direction away from the lower bearing plate (4), so that the vertical load is maintained at the test preset value; S3. Repair and reinforce the pipeline to be tested (28) under the test preset load, and cure it for a specified time to form a lining (30), and the lining (30) is closely attached to the inner wall of the pipeline to be tested (28); S4. Start the loading pump (12), and the loading cylinder (13) continues to gradually load the pipeline to be tested (28)-lining (30) system through the upper loading plate (1) until the pipeline to be tested (28)-lining (30) system is completely damaged to obtain the ultimate bearing capacity of the system under the secondary stress condition.

Images