Prestressed pipe pile pull-out test device

Abstract

The invention discloses a prestressed pipe pile pull-out test device, comprising a fixture, a fixture lifting mechanism, a tension measuring mechanism and a displacement measuring mechanism, wherein the fixture comprises a left fixture and a right fixture which are split, and the clamping ends of the left fixture and the right fixture are provided with a square metal frame which is open to the outside, and bolt connection holes are provided on the adjacent side walls of the square metal frames which are arranged oppositely on the left fixture and the right fixture, and bolts pass through the two bolt connection holes to clamp the left fixture and the right fixture to each other on the pile head, and a connection frame is provided on the adjacent square metal frame of the left fixture and the right fixture, and the connection frame has a bottom plate and side plates at both ends of the bottom plate, and the bottom plate and the two side plates of the connection frame are fixed on the outer side wall of the left fixture or the right fixture, and a through hole is provided on the bottom plate, and a pull rod with an external thread at the end passes through the through hole and is threadedly connected with a nut, and four pull rods are symmetrically provided on the left fixture and the right fixture. The fixture structure of the device is more solid, the tension applied to the pile body is more uniform, and the clamp clamping operation is more convenient.

Description

Technical Field

[0001] The invention relates to a prestressed pipe pile anti-pulling test device. Background Art

[0002] There are three methods for connecting the pile body and the jack in the existing pull-out test of prestressed concrete pipe piles. The first is the core filling method, which pours micro-expansive concrete in the pipe hole of the pipe pile and inserts a number of steel bars into the concrete. After the concrete is cured to reach the design strength, the steel bars or steel pull rods are connected together by welding to form a reaction force connection system. The second is the welding method, which uses a welding method to connect the steel plate at the end of the pipe pile with the transition steel plate or transition steel box to form a reaction force connection system. The third is the bolt connection method, which is to manually drill holes on the wall of the prestressed pipe pile, and the steel plate on the outside of the pile is connected to the pipe pile by bolts to form a reaction force connection system. The fourth is the hoop-type clamp connection method, which uses bolts to pressurize the hoop-type clamp and use the friction between the clamp and the pile body of the prestressed concrete pipe pile to provide a reaction force. However, the above four methods have the following defects:

[0003] (1) The disadvantage of the core filling method is that it requires pouring concrete and welding, which is labor-intensive and takes a long time to maintain. The quality of the reaction system connection is also difficult to ensure.

[0004] (2) The disadvantage of the welding method is that the steel plate at the end of the pile is easily pulled off, which is not suitable for testing the pull-out bearing capacity of prestressed piles with large pull-out resistance.

[0005] (3) The disadvantage of the bolt connection method is that holes are drilled on the wall of the prestressed pipe pile, causing damage to the pile body and affecting the later bearing performance of the pipe pile. Due to the brittleness of concrete, it is difficult to accurately form the hole diameter, the outer steel plate is prone to slip, and the bolts are unevenly stressed.

[0006] (4) The characteristic of the clamp-type connection method is that the friction between the clamp and the prestressed concrete pipe pile is used to provide a reaction force. In actual engineering, piles with large test pull-out forces are often at risk of being pulled off. In addition, in order to provide sufficient friction, the contact surface between the clamp and the test pile body must be increased and the bolt tightening force must be increased. Therefore, the clamp-type clamp will be relatively bulky. The structure of the clamp-type clamp can refer to the Chinese invention patent with announcement number CN204000972U. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a prestressed pipe pile pull-out test device, the fixture structure used in the device has better firmness, the pulling force applied to the pile body is more uniform, and the fixture clamping operation is more convenient.

[0008] To this end, the present invention provides a prestressed pipe pile pull-out test device, including a clamp, a clamp lifting mechanism, a tension measuring mechanism and a displacement measuring mechanism. The clamp includes a left clamp and a right clamp that are opened in half, and is characterized in that: the outer sides of the clamping ends of the left clamp and the right clamp are provided with a square metal frame that is open to the outside, and a plurality of bolt connection holes are provided on the adjacent side walls of the square metal frames that are relatively arranged on the left clamp and the right clamp. Bolts pass through the two bolt connection holes to clamp the left clamp and the right clamp to each other on the pile head. A connecting frame is provided on the left clamp and the right clamp adjacent to the square metal frame. The connecting frame has a bottom plate and side plates at both side ends of the bottom plate. The bottom plate and the two side plates of the connecting frame are fixed on the outer side wall of the left clamp or the right clamp. A through hole is provided on the bottom plate, and a pull rod with an external thread on the end passes through the through hole and is threadedly connected to a nut. At least four pull rods are symmetrically provided on the left clamp and the right clamp.

[0009] Technical effects of the present invention:

[0010] 1. The structural firmness of the clamp is better: in the clamp of the present invention, the square metal frame and the connecting frame are fixedly arranged on the clamp and are used to clamp the left clamp and the right clamp, and the force of tightening the bolts can be transmitted to the clamp through the square metal frame and the connecting frame of the integrated structure, so that the tightening force of the bolts will not be concentrated in one place, avoiding uneven force or local fracture and damage, and the square metal frame can protect the bolt connection mechanism from external pile drivers and contamination, and the connecting frame can also protect the pull rod part, thereby improving the structural stability.

[0011] 2. More uniform tension: The pull rod passes through the symmetrically distributed bottom plate through holes of the connection frame and is connected to the bolts, pulling up the entire evidence fixture in the vertical direction, so that the tension applied to the fixture is more uniform and the test data obtained is also more uniform.

[0012] 3. The clamping operation is more convenient and quick: the metal connecting sleeve is directly connected to the metal end plate of the pile body with bolts to block the clamp.

[0013] 4. The clamp is clamped more firmly: a metal connecting sleeve is bolted to the metal end plate of the pile body to block the clamp, and the clamp is clamped by a hoop, which can withstand greater tension under the double force. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the side structure of the prestressed pipe pile pull-out test device provided in Example 1 of the present invention.

[0015] Figure 2 for Figure 1 Schematic diagram of the top view of the prestressed pipe pile pull-out test device.

[0016] Figure 3 for Figure 2 Schematic diagram of the top view of the fixture.

[0017] Figure 4 for Figure 1 Schematic diagram of the structural section of the prestressed pipe pile pull-out test device. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The specific embodiments described therein are only used to explain the present invention and are not used to limit the present invention.

[0019] Reference Figure 1-4 As shown, the prestressed pipe pile pull-out test device provided by the present invention comprises a fixture, a fixture pulling mechanism, a tension measuring mechanism and a displacement measuring mechanism, wherein the fixture comprises a left fixture 1 and a right fixture 2 which are split into two halves, wherein the outer sides of the clamping ends of the left fixture 1 and the right fixture 2 are provided with a square metal frame 3 which is open to the outside, and the adjacent side walls of the square metal frames 3 which are arranged opposite to each other on the left fixture 1 and the right fixture 2 are provided with a plurality of bolt connection holes 4, and bolts 5 pass through the two bolt connection holes 4 to connect the left fixture 1 and the right fixture 2. Clamped to each other on the pile head, the left clamp 1 and the right clamp 2 are provided with a connection frame 6 near the square metal frame 3, and the connection frame 6 has a bottom plate 7 and side plates 8 at both ends of the bottom plate 7. The bottom plate 7 and the side plates 8 of the connection frame 6 are fixed on the outer side wall of the left clamp 1 or the right clamp 2. A through hole 9 is provided on the bottom plate 7, and a tie rod 10 with an external thread at the end passes through the through hole 9 and is threadedly connected to a nut. At least four tie rods 10 are symmetrically provided on the left clamp 1 and the right clamp 2. In order to facilitate material collection, the tie rod 10 is a steel bar, and the lower end of the steel bar has the external thread. In order to increase the friction and make the friction more uniform, a rubber pad 11 is provided between the left clamp 1 and the right clamp 2 and the pile body 12.

[0020] Reference Figure 1-2 As shown, in order to make the fixture structure more solid, the side plate 8 close to the square metal frame 3 also constitutes a side panel 13 of the square metal frame 3, and the bottom plate 7 is integrally formed with the bottom panel 14 of the adjacent square metal frame 3.

[0021] Reference Figure 1-3As shown, in order to further improve the firmness of the clamp on the pile body 12, a metal connecting sleeve 15 is sleeved on the end of the pile head, and the metal connecting sleeve 15 is sleeved on the pile head and is on the upper side of the clamp. A connecting through hole 16 is distributed in an annular manner on the end of the metal connecting sleeve 15. A metal end plate 17 is fixedly provided on the end of the pile body, and a threaded hole 18 is provided on the metal end plate 17 corresponding to the connecting through hole 16. The screw 19 passes through the connecting through hole 16 on the metal connecting sleeve 15 and is threadedly connected with the threaded hole 18 on the metal end plate 17, thereby fixing the metal connecting sleeve 15 on the pile end, and the upper sides of the left clamp 1 and the right clamp 2 are blocked by the lower edge of the metal connecting sleeve 15.

Claims

1. A prestressed pipe pile pull-out test device, comprising a fixture, a fixture lifting mechanism, a tension measuring mechanism and a displacement measuring mechanism, wherein the fixture comprises a left fixture and a right fixture that are split, and wherein: The outer sides of the clamping ends of the left clamp and the right clamp are provided with a square metal frame that is open to the outside, and a plurality of bolt connection holes are provided on the adjacent side walls of the square metal frames that are relatively arranged on the left clamp and the right clamp, and the bolts pass through the two bolt connection holes to clamp the left clamp and the right clamp to each other on the pile head, and a connecting frame is provided adjacent to the square metal frame on the left clamp and the right clamp, and the connecting frame has a bottom plate and side plates at both side ends of the bottom plate, and the bottom plate and the two side plates of the connecting frame are fixed to the outer side walls of the left clamp or the right clamp, and a through hole is provided on the bottom plate, and a pull rod with an external thread at the end passes through the through hole and is threadedly connected to a nut, and at least four pull rods are symmetrically provided on the left clamp and the right clamp; the pull rod is a steel bar, and the lower end of the steel bar The part has the external thread; a side panel close to the square metal frame also constitutes a side panel of the square metal frame, and the bottom plate is integrally formed with the bottom panel of the adjacent square metal frame; a rubber pad is arranged between the left clamp and the right clamp and the pile body; a metal connecting sleeve is sleeved on the end of the pile head, and the metal connecting sleeve is sleeved on the pile head and is on the upper side of the clamp, and connecting through holes are distributed in an annular manner on the end of the metal connecting sleeve, and a metal end plate is fixedly arranged on the end of the pile body, and threaded holes are arranged on the metal end plate corresponding to the connecting through holes, and the screw passes through the connecting through holes on the metal connecting sleeve and is threadedly connected with the threaded holes on the metal end plate, thereby fixing the metal connecting sleeve to the pile end, and the upper sides of the left clamp and the right clamp are blocked by the lower edge of the metal connecting sleeve.

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