Slow-setting prestressed uplift pile with test pile equipment

Abstract

This invention discloses a test pile device for slow-setting prestressed pull-out piles, aiming to provide a test pile device suitable for testing the pull-out bearing capacity of slow-setting prestressed pull-out piles and effectively improving the accuracy of the pull-out bearing capacity test. It includes a main reaction beam with a steel strand fixing device for fixing the steel strands, a vertical tie rod on the main reaction beam with a limiting block located below the main reaction beam, a lifting device for lifting the reaction beam, and a reinforcing bar fixing beam for fixing the reinforcing bars connecting the slow-setting prestressed pull-out pile. The reinforcing bar fixing beam is located below the main reaction beam and has a vertical through hole that cooperates with the vertical tie rod, through which the vertical tie rod passes. The limiting block is located below the reinforcing bar fixing beam.

Description

Technical Field

[0001] This invention relates to a test pile device, specifically a test pile device for slow-setting prestressed pull-out piles. Background Technology

[0002] Building foundations include isolated foundations, strip foundations, raft foundations, and pile foundations. To balance safety and economy, high-rise buildings and some multi-story buildings generally use pile foundations. Based on function, piles can be divided into compression piles and tension piles. Compression piles bear the weight of the building itself, while tension piles withstand the buoyancy of groundwater in the foundation. With the rapid development of urban construction, the development of underground space has become a hot topic. Increased basement depth leads to increased buoyancy from groundwater, especially in coastal areas with high groundwater levels; the issue of buoyancy resistance in buildings has always been a concern in the engineering field.

[0003] Since the compressive strength of concrete is much greater than its tensile strength, the decisive factor in the cost of tension piles is often the cracks in the pile body, and the utilization rate of the steel reinforcement inside the pile is generally less than 50%. In order to improve the anti-buoyancy efficiency and effectively control the cracks in the tension pile body, some inventors have developed "slow-setting prestressed cast-in-place piles and methods for tension resistance", such as the slow-setting bonded prestressed tension pile connection device and its construction method in Chinese patent 202111131082X. This type of pile is composed of concrete, ordinary steel reinforcement and slow-setting prestressing tendons. The slow-setting prestressing tendons include steel strands and sleeves fitted outside the steel strands.

[0004] When promoting and applying slow-setting prestressed pull-out piles, the inventors discovered the following problems: Since slow-setting prestressed pull-out piles are a new pile type, according to Article 3.1.2 of the "Technical Specification for Testing Building Foundation Piles" (JGJ106-2014), a single pile vertical pull-out static load test must be conducted before construction. Currently, in conventional pull-out pile vertical pull-out static load tests, the reinforcing steel bars inside the pull-out pile are generally welded to the side wall of the crossbeam of the test pile device. A jack applies an upward pull force (i.e., lifting force) to the internal reinforcing steel bars by lifting the crossbeam, thereby testing the ultimate bearing capacity of the single pile. This test pile device is simple and effective to use in conventional pull-out piles and is easy to operate; however, the following problems exist when applied to slow-setting prestressed pull-out piles.

[0005] Because the steel strands in the slow-setting prestressed tendons cannot be welded, the upward force provided by the jack in the static load test of a single pile will be entirely borne by the ordinary steel reinforcement. However, the vertical bearing capacity of the slow-setting prestressed pile is jointly borne by the ordinary steel reinforcement and the slow-setting prestressed tendons. Therefore, if a conventional pile testing device is used to conduct a static load test of the vertical pull-out of the slow-setting prestressed pile, the result will inevitably be that the steel reinforcement breaks, and the pull-out bearing capacity of the slow-setting prestressed pile cannot be effectively evaluated.

[0006] Furthermore, if the steel strands are fixed to the crossbeam using other fixing structures, so that the steel strands and reinforcing bars are fixed together on the crossbeam for a single pile vertical pull-out static load test, the following problems still exist. Because the steel strands in the slow-setting prestressed tendons have an outer jacket, the steel strands are separated from the concrete pile, and the steel strands will produce a large elongation under tension, while the reinforcing bars will produce a very small elongation under tension. Therefore, during the test, the pull-out force provided by the jack will still be almost entirely borne by the ordinary reinforcing bars, and the steel strands will still be unable to bear the pull-out force provided by the jack. As a result, the reinforcing bars will inevitably break, and the pull-out bearing capacity of the slow-setting prestressed pull-out pile cannot be effectively evaluated. Summary of the Invention

[0007] The purpose of this invention is to provide a test pile device for slow-setting prestressed pull-out piles, which is suitable for testing the pull-out bearing capacity of slow-setting prestressed pull-out piles and can effectively improve the accuracy of the pull-out bearing capacity test of slow-setting prestressed pull-out piles.

[0008] The technical solution of this invention is:

[0009] A test pile device for a slow-setting prestressed tension pile, the slow-setting prestressed tension pile comprising steel strands and reinforcing bars, including:

[0010] The main reaction beam is equipped with a steel strand fixing device for fixing the steel strands. The main reaction beam is also equipped with a vertical tie rod, and a limit stop is provided on the vertical tie rod, with the limit stop located below the main reaction beam.

[0011] The lifting device is used to lift the reaction beam;

[0012] The reinforcing bar fixing beam is used to fix and connect the reinforcing bars of the slow-setting prestressed pull-out pile. The reinforcing bar fixing beam is located below the main reaction beam. The reinforcing bar fixing beam is provided with vertical through holes that cooperate with vertical tie rods. The vertical tie rods pass through the corresponding vertical through holes. The limiting block is located below the reinforcing bar fixing beam.

[0013] When testing the pull-out bearing capacity of slow-setting prestressed pull-out piles using a test pile equipment, the steel strands of the slow-setting prestressed pull-out piles are fixed to the main reaction beam using a steel strand fixing device, and the reinforcing bars of the slow-setting prestressed pull-out piles are fixed to the reinforcing bar fixing beam, with a set distance between the limiting block and the reinforcing bar fixing beam. Then, the reaction beam is lifted upwards using a jacking device. During this process, the steel strands of the slow-setting prestressed pull-out piles are first stressed and elongated, so that the reaction beam, vertical tie rod, and limiting block move upwards synchronously. When the limiting block abuts against the lower surface of the reinforcing bar fixing beam, the steel strands and reinforcing bars of the slow-setting prestressed pull-out piles jointly bear the jacking force of the jacking device. In this way, by setting the distance between the limiting block and the reinforcing beam, the steel strands are initially stressed and elongated when the lifting device initially lifts the reaction beam. After the limiting block rests on the lower surface of the reinforcing beam, the steel strands are stretched and almost stop elongating. Subsequently, the steel strands and reinforcing bars of the slow-setting prestressed pull-out pile jointly bear the lifting force of the lifting device, thereby effectively improving the accuracy of the pull-out bearing capacity test of the slow-setting prestressed pull-out pile. Therefore, it is suitable for testing the pull-out bearing capacity of slow-setting prestressed pull-out piles.

[0014] On the other hand, the test pile equipment for slow-setting prestressed pull-out piles only requires applying a lifting force through a jacking device to lift the jacking reaction beam upwards, which can then be used to test the pull-out bearing capacity of the slow-setting prestressed pull-out piles and ensure the accuracy of the pull-out bearing capacity test; without the need for a step-by-step operation of first using one jacking device to load and lift the steel strands, and then using another jacking device to lift the steel strands and reinforcing bars simultaneously. This not only saves one jacking device, simplifying the equipment structure and reducing costs, but also eliminates the step of pre-lifting the steel strands, simplifying the operation steps.

[0015] Preferably, the lower part of the vertical tie rod is a threaded rod with a limiting nut on it. The limiting nut is located below the reinforcing bar fixing beam, and this limiting nut constitutes the limiting stop. Thus, by adjusting the position of the limiting nut on the threaded rod, the set distance between the limiting stop and the reinforcing bar fixing beam can be easily adjusted to suit the use of slow-setting prestressed pull-out piles of different lengths (the lengths of the steel strands in slow-setting prestressed pull-out piles of different lengths are different, and the deformation produced by hand-pulling is also different depending on the length of the steel strands).

[0016] Preferably, the reinforcing steel fixing beam is provided with a vertical sleeve, and the inner hole of the vertical sleeve constitutes the aforementioned vertical through hole. This facilitates the actual processing and fabrication of the vertical through hole.

[0017] Preferably, the steel strand fixing device consists of anchors. This allows the steel strands to be stably and reliably fixed to the main reaction beam, while also facilitating disassembly.

[0018] Preferably, the reinforcing bars of the slow-setting prestressed pull-out pile are fixed to the reinforcing bar fixing beam by welding. In this way, the reinforcing bars can be stably and reliably fixed to the reinforcing bar fixing beam.

[0019] Preferably, the reinforcing bars of the slow-setting prestressed pull-out piles are fixed to the reinforcing bar fixing beam using anchorages. This ensures that the reinforcing bars are stably and reliably fixed to the reinforcing bar fixing beam using anchorages, while also facilitating disassembly.

[0020] Preferably, the reinforcing bar fixing beam is also equipped with support feet to support the beam. Thus, when fixing the reinforcing bars to the beam, the support feet can support the beam on the ground, facilitating the operation of fixing the reinforcing bars to the beam.

[0021] Preferably, the device also includes anchor piles, which are anchored into the ground to support the jacking device, which is supported on the top surface of the anchor piles.

[0022] Preferably, the main reaction beam is made of square steel, and both the upper and lower surfaces of the main reaction beam are provided with steel strand through holes, and the steel strand fixing device is set on the upper surface of the main reaction beam.

[0023] The beneficial effects of this invention are: it is applicable to the pull-out bearing capacity test of slow-setting prestressed pull-out piles, and can effectively improve the accuracy of the pull-out bearing capacity test of slow-setting prestressed pull-out piles. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the test pile equipment for slow-setting prestressed pull-out piles of the present invention in a certain state during actual application.

[0025] Figure 2 This is a schematic diagram of another state of the test pile equipment for slow-setting prestressed pull-out piles of the present invention during actual application.

[0026] In the picture:

[0027] Main reaction beam 1;

[0028] Lifting device 2;

[0029] Reinforcing steel beam 3, support leg 3.1;

[0030] Anchor pile 4;

[0031] 5. Steel strand fixing device;

[0032] Vertical tie rod 6;

[0033] Limit stop 7;

[0034] Vertical through hole 8;

[0035] Screw 9;

[0036] 10 slow-setting prestressed pull-out piles;

[0037] 11 steel bars;

[0038] 12 strands of steel. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0040] Specific Implementation Example 1: As shown in the example Figure 1 As shown, a test pile device for slow-setting prestressed pull-out piles is disclosed. The slow-setting prestressed pull-out pile 10 includes steel strands 12 and reinforcing bars 11. The test pile device includes a main reaction beam 1, a jacking device 2, and a reinforcing bar fixing beam 3. A steel strand fixing device 5 for fixing the steel strands is provided on the main reaction beam. In this embodiment, the steel strand fixing device consists of several anchors. The main reaction beam is horizontally distributed. A vertical tie rod 6 is provided on the main reaction beam, and a limiting block 7 is provided on the vertical tie rod, with the limiting block located below the main reaction beam. The jacking device is used to lift the reaction beam. In this embodiment, the jacking device is a jack. The reinforcing bar fixing beam 3 is used to fix and connect the reinforcing bars of the slow-setting prestressed pull-out pile. The reinforcing bar fixing beam is located below the main reaction beam, and a vertical through hole 8 that cooperates with the vertical tie rod is provided on the reinforcing bar fixing beam. The vertical tie rod passes through the corresponding vertical through hole. The limiting block is located below the reinforcing bar fixing beam.

[0041] When testing the pull-out bearing capacity of slow-setting prestressed pull-out piles using test pile equipment,

[0042] like Figure 1 As shown, the steel strands of the slow-setting prestressed pull-out pile are fixed to the main reaction beam using a steel strand fixing device. Specifically, the steel strands are reliably and stably fixed to the main reaction beam using anchors, with one anchor fixing one steel strand. The reinforcing bars of the slow-setting prestressed pull-out pile are fixed to the reinforcing bar fixing beam, and there is a set distance between the limiting block and the reinforcing bar fixing beam. This set distance is 0.5%-0.8% of the length of the steel strand (the maximum elongation of the steel strand under tension is 0.5%-0.8% of the length of the steel strand). In this embodiment, the set distance is 0.6% of the length of the steel strand. Next, the reaction beam is lifted upwards using a jacking device. During this process, the steel strands of the slow-setting prestressed pull-out pile are first stressed and elongated, so that the reaction beam, vertical tie rod, and limiting block move upwards synchronously. Figure 2As shown, when the limiting block abuts against the lower surface of the reinforcing beam, the steel strands and reinforcing bars of the slow-setting prestressed pull-out pile jointly bear the lifting force of the jacking device. Thus, by setting a distance between the limiting block and the reinforcing beam, the steel strands initially experience stress and elongate when the jacking device lifts the reaction beam upwards. After the limiting block abuts against the lower surface of the reinforcing beam, the steel strands are under tension and almost stop elongating. Subsequently, the steel strands and reinforcing bars of the slow-setting prestressed pull-out pile jointly bear the lifting force of the jacking device, thereby effectively improving the accuracy of the pull-out bearing capacity test of the slow-setting prestressed pull-out pile. Therefore, it is suitable for testing the pull-out bearing capacity of slow-setting prestressed pull-out piles.

[0043] On the other hand, the test pile equipment for slow-setting prestressed pull-out piles only requires applying a lifting force through a jacking device to lift the reaction beam upwards, which can then be used to test the pull-out bearing capacity of the slow-setting prestressed pull-out piles and ensure the accuracy of the pull-out bearing capacity test; without the need for a step-by-step operation of first using one jacking device to load and lift the steel strands, and then using another jacking device to lift the steel strands and reinforcing bars simultaneously. This not only saves one jacking device, simplifying the equipment structure and reducing costs, but also eliminates the step of pre-lifting the steel strands, simplifying the operation steps.

[0044] Specifically, such as Figure 1 As shown, the test pile equipment for slow-setting prestressed pull-out piles also includes anchor piles 4. The anchor piles are anchored into the ground to support the jacking device, which is supported on the top surface of the anchor piles. In this embodiment, there are two anchor piles. The jacking device includes two jacks, one jack located on the top surface of one anchor pile and the other jack located on the top surface of the other anchor pile. The two jacks simultaneously lift the reaction beam upwards.

[0045] There are two vertical tie rods (6 in total), and the steel strand fixing device is located between the two vertical tie rods. Each vertical through-hole corresponds to one of the vertical tie rods, and the vertical tie rod passes through the corresponding vertical through-hole.

[0046] In this embodiment, both the main reaction beam and the reinforcing bar fixing beam are provided with steel strand through holes. The steel strands pass through the steel strand through holes on the reinforcing bar fixing beam and the main reaction beam sequentially from bottom to top, and are then fixed to the steel strand fixing device.

[0047] In one embodiment of this invention, the reinforcing bars of the slow-setting prestressed pull-out pile are fixed to the reinforcing bar fixing beam by welding. This ensures that the reinforcing bars are stably and reliably fixed to the reinforcing bar fixing beam.

[0048] In another embodiment of this invention, the reinforcing bars of the slow-setting prestressed pull-out pile are fixed to the reinforcing bar fixing beam using anchorages. This ensures that the reinforcing bars are stably and reliably fixed to the reinforcing bar fixing beam using anchorages, while also facilitating disassembly.

[0049] Furthermore, such as Figure 1 As shown, the lower part of the vertical tie rod 6 is a screw rod 9, on which a limiting nut is provided. The limiting nut is located below the reinforcing bar fixing beam, and this limiting nut constitutes the limiting stop. In this way, by adjusting the position of the limiting nut on the screw rod, the set distance between the limiting stop and the reinforcing bar fixing beam can be easily adjusted to suit the use of slow-setting prestressed pull-out piles of different lengths (the length of the steel strands in slow-setting prestressed pull-out piles of different lengths is different, and the deformation produced by hand pulling is also different due to the different lengths of the steel strands).

[0050] Furthermore, a vertical sleeve is provided on the reinforcing steel fixing beam, and the inner hole of the vertical sleeve constitutes the aforementioned vertical through hole. This facilitates the actual processing and fabrication of the vertical through hole.

[0051] Furthermore, such as Figure 1 As shown, the reinforcing bar fixing beam 3 is also equipped with support feet 3.1, which are used to support the reinforcing bar fixing beam. In this way, when fixing the reinforcing bars to the reinforcing bar fixing beam, the support feet can support the reinforcing bar fixing beam on the ground surface, which facilitates the operation of fixing the reinforcing bars to the reinforcing bar fixing beam.

[0052] Furthermore, the main reaction beam is constructed of square steel, with steel strand through-holes on both its upper and lower surfaces. The steel strand fixing device is located on the upper surface of the main reaction beam. Because the main reaction beam is made of square steel, when the reinforcing bars of the slow-setting prestressed pull-out piles are fixed to the reinforcing bar fixing beam by welding, the reinforcing bars can be welded to the side of the square steel. This ensures that the reinforcing bars are stably and reliably fixed to the reinforcing bar fixing beam.

[0053] Of course, the main reaction beam can also be made of other steel sections or steel beams. For example, the main reaction beam can also be made of channel steel with the opening facing upward. When the reinforcing bars of the slow-setting prestressed pull-out pile are fixed to the reinforcing bar fixing beam by welding, the reinforcing bars can be welded to the side of the channel steel.

[0054] The reinforcing bar fixing beam is made of steel beams, which can be steel beams or other types of steel beams.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A test pile device for slow-setting prestressed tension piles, the slow-setting prestressed tension pile comprising steel strands and reinforcing bars, characterized in that, include: The main reaction beam is equipped with a steel strand fixing device for fixing the steel strands. The main reaction beam is also equipped with a vertical tie rod, and a limit stop is provided on the vertical tie rod, with the limit stop located below the main reaction beam. The lifting device is used to lift the main reaction beam; The reinforcing bar fixing beam is used to fix and connect the reinforcing bars of the slow-setting prestressed pull-out pile. The reinforcing bar fixing beam is located below the main reaction beam. The reinforcing bar fixing beam is provided with vertical through holes that cooperate with vertical tie rods. The vertical tie rods pass through the corresponding vertical through holes. The limiting block is located below the reinforcing bar fixing beam, and there is a set distance between the limiting block and the reinforcing bar fixing beam.

2. The test pile equipment for slow-setting prestressed pull-out piles according to claim 1, characterized in that, in When testing the pull-out bearing capacity of slow-setting prestressed pull-out piles using pile testing equipment, the steel strands of the slow-setting prestressed pull-out piles are fixed to the main reaction beam using a steel strand fixing device, and the reinforcing bars of the slow-setting prestressed pull-out piles are fixed to the reinforcing bar fixing beam. Then, the main reaction beam is lifted upwards using a jacking device. During this process, the steel strands of the slow-setting prestressed pull-out piles are first subjected to force and elongated, so that the main reaction beam, vertical tie rod, and limiting block move upwards synchronously. When the limiting block abuts against the lower surface of the reinforcing bar fixing beam, the steel strands and reinforcing bars of the slow-setting prestressed pull-out piles jointly bear the jacking force of the jacking device.

3. The test pile equipment for slow-setting prestressed pull-out piles according to claim 1, characterized in that, The lower part of the vertical tie rod is a screw rod, and a limiting nut is provided on the screw rod. The limiting nut is located below the steel reinforcement fixing beam, and the limiting nut constitutes the limiting block.

4. The test pile equipment for slow-setting prestressed pull-out piles according to claim 1, 2, or 3, characterized in that, The steel reinforcement fixing beam is provided with a vertical sleeve, and the inner hole of the vertical sleeve constitutes the vertical through hole.

5. The test pile equipment for slow-setting prestressed pull-out piles according to claim 1, 2, or 3, characterized in that, The steel strand fixing device consists of anchors.

6. The test pile equipment for slow-setting prestressed pull-out piles according to claim 1, 2, or 3, characterized in that, The reinforcing bars of the slow-setting prestressed pull-out pile are fixed to the reinforcing bar fixing beam by welding.

7. The test pile equipment for slow-setting prestressed pull-out piles according to claim 1, 2, or 3, characterized in that, The reinforcing bars of the slow-setting prestressed pull-out pile are fixed to the reinforcing bar fixing beam by anchorage.

8. The test pile equipment for slow-setting prestressed pull-out piles according to claim 1, 2, or 3, characterized in that, The steel reinforcement fixing beam is also provided with support feet, which are used to support the steel reinforcement fixing beam.

9. The test pile equipment for slow-setting prestressed pull-out piles according to claim 1, 2, or 3, characterized in that, It also includes anchor piles, which are anchored into the ground to support the jacking device, which is supported on the top surface of the anchor piles.

10. The test pile equipment for slow-setting prestressed pull-out piles according to claim 1, 2, or 3, characterized in that, The main reaction beam is made of square steel, and steel strand through holes are provided on both the upper and lower surfaces of the main reaction beam. The steel strand fixing device is set on the upper surface of the main reaction beam.

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