A fully assembled self - resetting prestressed high - strength concrete pipe pile - pile cap foundation system and construction method

Abstract

The present invention relates to the technical field related to the structure of the connection between prestressed high-strength concrete pipe piles and pile caps, and specifically relates to a fully assembled self-centering high-strength concrete pipe pile - pile cap foundation system and construction method, including a lower clamping spring part and an upper clamping spring part. A hollow cylinder is movably arranged in the corresponding holes of the lower clamping spring part and the upper clamping spring part. A steel bar is movably arranged in the hollow cylinder. Lower and upper threaded parts are respectively arranged at both ends of the steel bar. The lower threaded part of the steel bar can pass through the lower end of the hollow cylinder and is in threaded cooperation with the internal thread on the inner wall of the cylinder body of the mechanical sleeve. The upper threaded part of the steel bar can pass through the upper end of the hollow cylinder and is threadedly provided with a nut that is in limit cooperation with the upper clamping spring plate at the upper end of the upper clamping spring part. The present invention can reduce the residual deformation of the foundation after a large horizontal earthquake action, achieving the effect that the connection node at the epicenter does not suffer obvious damage and basically does not need to be repaired after the earthquake.

Description

Technical Field

[0001] The present invention relates to the technical field related to the connection structure between prestressed high-strength concrete pipe piles and pile caps, and specifically to a fully assembled self-centering high-strength concrete pipe pile - pile cap foundation system and a construction method thereof. Background Art

[0002] With the rapid development of pile foundation engineering technology, its seismic safety issues deserve more attention. Prestressed high-strength concrete pipe piles are widely used in China. Its advantages are high single-pile bearing capacity, low production cost, small reinforcement ratio, steel saving, energy conservation and environmental protection, large bearing capacity of single-sided concrete, and high construction efficiency. The currently mature and general technology is to use anchor bars to connect PHC pipe piles and reinforced concrete pile caps. However, when the superstructure is subjected to a large horizontal seismic action, the connection nodes between the prestressed high-strength concrete pipe piles and the pile caps will rotate, which will have an adverse impact on both the pile caps and the prestressed pipe piles. In severe cases, it will cause cracking and damage to the pile heads and pile caps of the prestressed pipe piles, and will also cause the pile caps to rupture due to insufficient anti-overturning capacity of the superstructure. Summary of the Invention

[0003] In order to reduce the adverse effects of horizontal load seismic action on the pipe piles and pile caps, the present invention provides a fully assembled self-centering high-strength concrete pipe pile - pile cap foundation system and a construction method thereof. This system can reduce residual deformation, thereby protecting the overall stability of the superstructure, saving repair time, enabling the connection nodes between the pile caps and the piles under horizontal load action not to be severely damaged, making the structure more reliable, and reducing repair costs.

[0004] The present invention is realized through the following technical solutions: A fully assembled self-centering high-strength concrete pipe pile - pile cap foundation system, including a self-centering device disposed between the precast reinforced concrete pile cap and the prestressed high-strength concrete pipe pile;

[0005] A number of prestressing tendons are pre-arranged circumferentially and uniformly in the pile body of the prestressed high-strength concrete pipe pile. A PHC pipe pile end plate is provided at the pile end of the prestressed high-strength concrete pipe pile. A mechanical sleeve is correspondingly provided on the PHC pipe pile end plate opposite to the prestressing tendons. The prestressing tendons and the bottom of the mechanical sleeve are fixedly connected in a manner of mechanical connection of steel bars. An internal thread is provided on the inner wall of the barrel of the mechanical sleeve;

[0006] The self-centering device includes a lower clamping spring part and an upper clamping spring part. The lower clamping spring part includes a lower group of disc spring plates with a number of disc spring plates superposed together in the same direction, and lower clamping plates respectively clamped at the upper and lower ends of the lower group of disc spring plates. The convex surfaces of the disc spring plates of the lower group of disc spring plates face upward;

[0007] The upper clamping spring part comprises an upper disc spring plate group in which a plurality of disc spring plates are stacked together in the same direction, and upper clamping spring plates are respectively arranged at the upper and lower ends of the upper disc spring plate group, and the convex surface of the disc spring plates of the upper disc spring plate group is arranged downward;

[0008] The lower clamping spring part and the upper clamping spring part are correspondingly reserved with a plurality of channels along the circumference, and hollow cylinders are movably arranged in the corresponding channels of the lower clamping spring part and the upper clamping spring part, and all the hollow cylinders correspond to the mechanical sleeves one by one, and a steel rod is movably arranged in the hollow cylinder, and the two ends of the steel rod are respectively provided with a lower threaded part and an upper threaded part, and the lower threaded part of the steel rod can pass through the lower end of the hollow cylinder and cooperate with the internal thread of the cylinder inner wall of the mechanical sleeve, and the upper threaded part of the steel rod can pass through the upper end of the hollow cylinder and is threadedly provided with a nut that cooperates with the upper clamping spring plate at the upper end of the upper clamping spring part; the top cover of the upper clamping spring plate is provided with a cover plate;

[0009] A circular cross-section groove at the bottom of the assembled reinforced concrete cap is reserved at the bottom of the cap, which is compatible with the pile body of the prestressed high-strength concrete pipe pile, and a reserved space for accommodating and cooperating with the self-resetting device is reserved inside the assembled reinforced concrete cap.

[0010] As a further improvement of the technical solution of the present invention, the diameter of the circular cross-section groove at the bottom of the support platform gradually increases from top to bottom.

[0011] As a further improvement of the technical solution of the present invention, an annular notch adapted to the nut is reserved on the outer edge of the lower portion of the cover plate.

[0012] As a further improvement of the technical solution of the present invention, the nut is a flange nut.

[0013] The present invention further provides a construction method of a fully assembled self-resetting high-strength concrete pipe pile-cap foundation system, comprising the following steps:

[0014] S1, sinking prestressed high-strength concrete pipe piles into the foundation by static pressure method or hammer method;

[0015] S2, threading the lower threaded portion of the steel rod to the inner wall of the mechanical sleeve embedded in the head of the prestressed high-strength concrete pipe pile;

[0016] S3, after all the steel bars are connected to the prestressed high-strength concrete piles, a hollow cylinder is placed on the outside of each steel bar;

[0017] S4, press the lower clamping spring plate at the lower end of the clamping spring part, a plurality of disc spring plates, and the lower clamping spring plate at the upper end in sequence, insert from the upper end of the hollow cylinder, and place them one by one until they are stable;

[0018] S5. Assemble the prefabricated precast reinforced concrete pile cap so that the prestressed high-strength concrete pipe pile enters the circular cross-section groove at the bottom of the pile cap, and also makes the lower clamping spring part located in the lower space of the reserved space;

[0019] S6. Insert from the upper end of the hollow cylinder in the order of the upper clamping spring plate at the lower end of the upper clamping spring part, several disc spring plates, and the upper clamping spring plate at the upper end, and place them one by one until they are stable;

[0020] S7. Connect the upper threaded parts of all steel bars to the corresponding nuts until the nuts are in limit fit with the upper clamping spring plate at the upper end, so that the upper clamping spring part is located in the upper space of the reserved space;

[0021] S8. Seal the upper space of the reserved space with a cover plate to complete the installation of the self-resetting device.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (1) For a structure without a self-resetting device, this device can reduce the residual deformation of the foundation after a large horizontal earthquake action, so that the connection nodes at the epicenter do not suffer obvious damage and basically do not need to be repaired after the earthquake. It can also reduce the influence of the upper load on the pile cap and pipe pile, and can avoid the formation of hinge connections at the connection part of the pile cap and pipe pile, thereby preventing the phenomenon of increased joint rotation capacity.

[0024] (2) For a structure with a self-resetting device, the present invention uses all prefabricated components and metal parts, avoiding the damage to the environment caused by on-site construction and improving the construction quality and construction efficiency.

[0025] (3) There is a gap between the pile head of the prestressed pipe pile and the pile cap, ensuring that the pile cap will not be damaged prematurely due to the extrusion force or prying force generated during the rotation of the pile end.

[0026] (4) The present invention is applicable to most prestressed pipe pile structures, applicable to a wide range of structural systems, with low requirements for the soil body and strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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 use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a front view of the overall assembly structure of the present invention.

[0029] Figure 2Side schematic view of the overall assembly structure of the present invention.

[0030] Figure 3 Front view of the pile cap of the present invention.

[0031] Figure 4 Top view of the pile cap of the present invention.

[0032] Figure 5 Enlarged detail view of the present invention.

[0033] Figure 6 Specific connection schematic diagram of the precast reinforced concrete pile cap and the precast column.

[0034] Figure 7 Three-dimensional view of a single disc spring plate.

[0035] Figure 8 For Figure 1 A-A sectional view.

[0036] Figure 9 For Figure 1 B-B sectional view.

[0037] Figure 10 Structural schematic diagram of the steel bar.

[0038] In the figure: 1 - precast column, 2 - precast reinforced concrete pile cap, 3 - early strength non-shrinkage grouting material, 4 - prestressed high-strength concrete pipe pile, 5 - cover plate, 6 - disc spring plate, 7 - steel bar, 8 - hollow cylinder, 9 - upper clamping spring plate, 10 - lower clamping spring plate, 11 - nut, 12 - PHC pipe pile end plate, 13 - reserved hole, 14 - circular cross-section groove at the bottom of the pile cap, 15 - mechanical sleeve, 16 - prestressed tendon, 17 - annular notch. Specific implementation mode

[0039] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work fall within the scope of protection of the present invention.

[0040] The present invention provides a specific embodiment of a fully assembled self-centering high-strength concrete pipe pile - pile cap foundation system, including a self-centering device arranged between the precast reinforced concrete pile cap 2 and the prestressed high-strength concrete pipe pile 4;

[0041] A number of prestressing tendons 16 are pre - arranged circumferentially and uniformly inside the pile body of the prestressed high - strength concrete pipe pile 4. A PHC pipe pile end plate 12 is provided at the pile end of the prestressed high - strength concrete pipe pile 4. A mechanical sleeve 15 is correspondingly provided on the PHC pipe pile end plate 12 opposite to the prestressing tendon 16. The prestressing tendon 16 and the bottom of the mechanical sleeve 15 are fixedly connected by means of mechanical connection of steel bars. An internal thread is provided on the inner wall of the cylinder body of the mechanical sleeve 15.

[0042] The self - resetting device includes a lower clamping spring part and an upper clamping spring part. The lower clamping spring part includes a lower disc spring plate group in which a number of disc spring plates 6 are superposed in the same direction, and lower clamping spring plates 10 respectively clamped at the upper and lower ends of the lower disc spring plate group. The convex surfaces of the disc spring plates 6 of the lower disc spring plate group are arranged upward.

[0043] The upper clamping spring part includes an upper disc spring plate group in which a number of disc spring plates 6 are superposed in the same direction, and upper clamping spring plates 9 respectively clamped at the upper and lower ends of the upper disc spring plate group. The convex surfaces of the disc spring plates 6 of the upper disc spring plate group are arranged downward.

[0044] A plurality of channels are reserved corresponding to each other along the circumference between the lower clamping spring part and the upper clamping spring part. A hollow cylinder 8 is movably arranged in the corresponding channels of the lower clamping spring part and the upper clamping spring part. All the hollow cylinders 8 correspond to the mechanical sleeves 15 one by one. A steel rod 7 is movably arranged in the hollow cylinder 8. Lower and upper threaded parts are respectively provided at both ends of the steel rod 7. The lower threaded part of the steel rod 7 can pass through the lower end of the hollow cylinder 8 and be in threaded fit with the internal thread on the inner wall of the cylinder body of the mechanical sleeve 15. The upper threaded part of the steel rod 7 can pass through the upper end of the hollow cylinder 8 and is provided with a nut 11 which is in limit fit with the upper clamping spring plate 9 at the upper end of the upper clamping spring part. A cover plate 5 is covered on the top of the upper clamping spring plate 9.

[0045] A circular cross - section groove 14 adapted to the pile body of the prestressed high - strength concrete pipe pile 4 is reserved at the bottom of the assembled reinforced concrete pile cap 2. A reserved space for accommodating the self - resetting device is reserved inside the assembled reinforced concrete pile cap 2.

[0046] As Figure 7 shown, the disc spring plate 6 is made of a steel plate with a certain thickness and a certain curvature. On the one hand, the steel plate has good toughness and can return to its original state after being stressed less than the elastic limit. Utilizing the good toughness of the steel plate, the steel plates are superposed together. The mechanical properties of the superposed steel plates are better than those of a single steel plate. After the precast column 1 bears a large horizontal load, the superposed disc spring plates 6 undergo elastic deformation, and the upper structure (including the precast column 1) rotates to a certain extent, and the natural vibration period changes, which can reduce the horizontal seismic energy transmitted to the upper structure.

[0047] On the other hand, the steel plate has a large rigidity, and the disc spring plate 6 will increase in rigidity after being stacked. When the upper structure is subjected to a small horizontal load, the disc spring plate 6 has a large rigidity after being stacked, and the self-reset device will not work. When and only when the prefabricated column 1 is subjected to a large horizontal load, the disc spring plate 6 will work to reduce the impact of the horizontal load on the pile of the prefabricated column 1.

[0048] Specifically, the radial dimension of the disc spring plate 6 is the same as that of the upper clamping spring plate 9 and the lower clamping spring plate 10 .

[0049] like Figure 1 As shown, the diameter of the circular cross-section groove 14 at the bottom of the pedestal gradually increases from top to bottom, that is, there is a certain angle between the inner wall of the groove and the outer wall of the prestressed high-strength concrete pipe pile 4. In the present invention, the top of the pile body of the prestressed high-strength concrete pipe pile 4 is gap-matched with the circular cross-section groove 14 at the bottom of the pedestal, leaving space for the pipe pile to rotate under horizontal action. When the upper structure (including the prefabricated column 1) is subjected to a large horizontal load, the pedestal will tilt, but because there is a certain angle between the prestressed high-strength concrete pipe pile 4 and the pedestal, the pedestal will not directly contact the prestressed high-strength concrete pipe pile 4, which prevents the pile head from being damaged first due to excessive pressure between the pile head and the pedestal before the self-resetting device is operated.

[0050] like Figure 5 As shown, in order to facilitate the installation of the cover plate 5 , an annular notch 17 matching the nut 11 is reserved at the outer edge of the lower portion of the cover plate 5 .

[0051] In order to improve the overall stability of the self-resetting device, the nut 11 is a flange nut.

[0052] The present invention further provides a construction method of a fully assembled self-resetting high-strength concrete pipe pile-cap foundation system, comprising the following steps:

[0053] S1, sinking prestressed high-strength concrete pipe piles 4 into the foundation by static pressure method or hammer method;

[0054] S2, threading the lower threaded portion of the steel rod 7 to the inner wall of the mechanical sleeve 15 embedded in the pile head of the prestressed high-strength concrete pipe pile 4;

[0055] S3, after all the steel bars 7 are connected to the prestressed high-strength concrete piles 4, a hollow cylinder 8 is placed on the outside of each steel bar 7;

[0056] S4, the lower clamping spring plate 10 at the lower end of the clamping spring part, the plurality of disc spring plates 6, and the lower clamping spring plate 10 at the upper end are inserted from the upper end of the hollow cylinder 8 in sequence, and are placed one by one until they are stable;

[0057] S5. Assemble the prefabricated precast reinforced concrete pile cap 2 so that the prestressed high-strength concrete pipe pile 4 enters the circular cross-section groove 14 at the bottom of the pile cap, and also makes the lower clamping spring part located in the lower space of the reserved space;

[0058] S6. Thread the upper clamping spring plate 9 at the lower end of the upper clamping spring part, several disc spring plates 6, and the upper clamping spring plate 9 at the upper end through the upper end of the hollow cylinder 8 in sequence and place them one by one until stable;

[0059] S7. Connect the upper threaded parts of all steel bars 7 to the corresponding nuts 11 until the nuts 11 are in limit fit with the upper clamping spring plate 9 at the upper end, so that the upper clamping spring part is located in the upper space of the reserved space;

[0060] S8. Seal the upper space of the reserved space with the cover plate 5 to complete the installation of the self-resetting device.

[0061] The present invention further provides a construction method for the precast column 1. Hoist the precast column 1 to the reserved hole 13 of the precast reinforced concrete pile cap 2, and pour early-strength non-shrinkage grouting material 3 between the precast column 1 and the reserved hole 13 to fill the gap between the column and the reserved hole 13. After the grouting material reaches the design strength, the precast reinforced concrete pile cap 2 and the precast column 1 are connected.

[0062] A major feature of the self-resetting device described in the present invention is that after the self-resetting device is subjected to a large load, it causes the self-resetting device to deform, and if the device is damaged, it can be replaced. The present invention also takes this major feature into account. After sealing the top surface of the pile cap with the cover plate 5, if the self-resetting device is damaged and needs to be replaced, the cover plate 5 can be opened to repair and replace the self-resetting device.

[0063] The above introduction is the specific construction method of a single self-resetting device. In engineering practice, it can be applied to single-pile pile caps, double-pile caps, and multi-pile caps.

[0064] Referring to Figure 6, in the case of no self-resetting device, assuming that the upper structure (including the precast column 1) of the double-pile cap is subjected to a large horizontal load to the right, the pile cap will rotate clockwise along the center of the pile cap, the left pile cap will displace upward, and the right pile cap will displace downward. If the pile cap and the prestressed high-strength concrete pipe pile 4 are fixedly connected by concrete and anchor bars, due to the large friction between the prestressed high-strength concrete pipe pile 4 and the surrounding soil, the prestressed high-strength concrete pipe pile 4 will not produce a large displacement, which will lead to: the anchor bars at the connection between the pile cap and the left prestressed high-strength concrete pipe pile 4 yield and plastic hinges appear, and the joint bearing capacity at the connection between the pile cap and the right prestressed high-strength concrete pipe pile 4 is insufficient and joint failure occurs. These two failure reasons will both affect the safety of the pile cap of the pile foundation.

[0065] As Figure 1, 4 As shown, in the present invention (when the self-resetting device is provided), when the superstructure (including the precast column 1) is subjected to a small horizontal load, due to the large connection stiffness between the pile and the cap, the self-resetting device will not work. When the superstructure is subjected to a large horizontal load (such as the wind load on high-rise buildings and high-rise structures during an earthquake, or the large horizontal load on the transmission line foundation), the displacement of the cap is the same as that of a common double-pile cap. The entire self-resetting device is connected to the prestressed high-strength concrete pipe pile 4 through the steel rod 7. Since the prestressed high-strength concrete pipe pile 4 will not produce a large displacement, when the left cap approximately moves upward, the prestressed high-strength concrete pipe pile 4 will provide a downward pulling force to the cap. The pulling force will not affect the cap, but will act on the left upper clamping spring part 9, flattening the disc spring plate 6; correspondingly, when the right cap approximately moves downward, the prestressed high-strength concrete pipe pile 4 will provide an upward supporting force to the cap. The supporting force will not affect the pile head, but will act on the right lower clamping spring part 10, flattening the disc spring plate 6. The self-resetting devices on the left and right sides of the precast reinforced concrete cap 2 complement each other. Without obvious damage to the connection node between the prestressed high-strength concrete pipe pile 4 and the cap, the influence of the superstructure on the cap and the pile after being loaded is reduced. The self-resetting device reduces the residual deformation of the foundation after a large horizontal earthquake action, thereby avoiding the adverse effects of a large horizontal load on the structure.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fully prefabricated self - resetting high - strength concrete pipe pile - pile cap foundation system, characterized in that, It comprises a self-resetting device arranged between an assembled reinforced concrete cap (2) and a prestressed high-strength concrete pipe pile (4); A plurality of prestressed tendons (16) are pre-distributed in a circumferential direction in the pile body of the prestressed high-strength concrete pipe pile (4); a PHC pipe pile end plate (12) is provided at the pile end of the prestressed high-strength concrete pipe pile (4); a mechanical sleeve (15) is correspondingly provided on the PHC pipe pile end plate (12) opposite to the prestressed tendons (16); the prestressed tendons (16) are fixedly connected to the bottom of the mechanical sleeve (15); and an internal thread is provided on the inner wall of the cylinder of the mechanical sleeve (15); The self-resetting device comprises a lower clamping spring portion and an upper clamping spring portion, the lower clamping spring portion comprising a lower disc spring plate group in which a plurality of disc spring plates (6) are stacked in the same direction, lower clamping spring plates (10) are respectively clamped at the upper and lower ends of the lower disc spring plate group, and the convex surfaces of the disc spring plates (6) of the lower disc spring plate group are arranged upward; The upper clamping spring portion comprises an upper disc spring plate group in which a plurality of disc spring plates (6) are stacked together in the same direction, and upper clamping spring plates (9) are respectively arranged at the upper and lower ends of the upper disc spring plate group, wherein the convex surfaces of the disc spring plates (6) of the upper disc spring plate group are arranged downwards; The lower clamping spring part and the upper clamping spring part are provided with a plurality of corresponding holes along the circumference, and hollow cylinders (8) are movably arranged in the corresponding holes of the lower clamping spring part and the upper clamping spring part, and all the hollow cylinders (8) correspond to the mechanical sleeve (15) one by one. A steel rod (7) is movably arranged in the hollow cylinder (8), and the two ends of the steel rod (7) are respectively provided with a lower threaded part and an upper threaded part, and the lower threaded part of the steel rod (7) can pass through the lower end of the hollow cylinder (8) and is threadably matched with the internal thread of the inner wall of the cylinder of the mechanical sleeve (15), and the upper threaded part of the steel rod (7) can pass through the upper end of the hollow cylinder (8) and is threadably provided with a nut (11) that is limitedly matched with the upper clamping spring plate (9) at the upper end of the upper clamping spring part; the top of the upper clamping spring plate (9) is covered with a cover plate (5); The bottom of the assembled reinforced concrete cap (2) is reserved with a cap bottom circular cross-section groove (14) adapted to the pile body of the prestressed high-strength concrete pipe pile (4), and the inside of the assembled reinforced concrete cap (2) is reserved with a reserved space for accommodating and cooperating with a self-resetting device.

2. The fully prefabricated self - resetting high - strength concrete pipe pile - pile cap foundation system according to claim 1, characterized in that, The diameter of the circular cross-section groove (14) at the bottom of the support platform gradually increases from top to bottom.

3. The fully prefabricated self - resetting high - strength concrete pipe pile - pile cap foundation system according to claim 1, characterized in that, An annular notch (17) adapted to fit the nut (11) is reserved at the lower outer edge of the cover plate (5).

4. The fully prefabricated self - resetting high - strength concrete pipe pile - pile cap foundation system according to claim 1, characterized in that, The nut (11) is a flange nut.

5. The construction method of the fully prefabricated self - resetting high - strength concrete pipe pile - pile cap foundation system according to claim 1 or 2 or 3 or 4, characterized in that, The steps include: S1, sinking prestressed high-strength concrete pipe piles (4) into the foundation by static pressure or hammering; S2, threading the lower threaded portion of the steel rod (7) to the inner wall of the mechanical sleeve (15) embedded in the pile head of the prestressed high-strength concrete pipe pile (4); S3, after all the steel bars (7) are connected to the prestressed high-strength concrete piles (4), a hollow cylinder (8) is placed on the outside of each steel bar (7); S4, insert the lower clamping spring plate (10) at the lower end of the clamping spring part, several disc spring plates (6), and the lower clamping spring plate (10) at the upper end into the hollow cylinder (8) in sequence from the upper end, and place them one by one until they are stable; S5, assemble the prefabricated assembled reinforced concrete cap (2) so that the prestressed high-strength concrete pipe pile (4) enters the circular cross-section groove (14) at the bottom of the cap, and also make the clamping spring part located in the lower space of the reserved space; S6, insert the upper clamping spring plate (9) at the lower end of the upper clamping spring part, several disc spring plates (6), and the upper clamping spring plate (9) at the upper end into the hollow cylinder (8) in sequence from the upper end, and place them one by one until they are stable; S7, connect the upper threaded parts of all steel bars (7) with the corresponding nuts (11) until the nuts (11) are in limit fit with the upper clamping spring plate (9) at the upper end, so that the upper clamping spring part is located in the upper space of the reserved space; S8, seal the upper space of the reserved space with the cover plate (5) to complete the installation of the self-resetting device.

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