Complete equipment for detecting vertical anti-pulling bearing capacity of large-tonnage single pile without foundation pretreatment

Abstract

The utility model aims to provide the anti-pulling platform which is simple to operate and capable of expanding the pressure-bearing area of the anti-pulling platform; according to the complete equipment for detecting the vertical anti-pulling bearing capacity of the large-tonnage single pile without foundation pretreatment, the requirement for the foundation bearing capacity of the periphery of a detected pile is lowered, damage to a pile body is reduced, the maximum anti-pulling test load allowable value is increased, the accuracy of test data is improved, and the anti-pulling installation detection efficiency is improved. The device comprises a detected pile, pile body longitudinal steel bars are poured on the detected pile, a plurality of first through holes in the vertical direction are formed in a counter-force lower frame, the pile body longitudinal steel bars are inserted into the first through holes, the multiple pile body longitudinal steel bars are inserted into the first through holes of the counter-force lower frame, and a tool anchorage device is arranged at the top of the counter-force lower frame. The upper portion of the pile body longitudinal steel bar is matched with a tool anchorage device in an anchoring mode, and the upper counter-force frame is connected with the lower counter-force frame through a plurality of 6m finish rolling deformed steel bars. The utility model is applied to the technical field of uplift piles.

Description

Technical Field

[0001] The utility model is applied to the technical field of pull-out piles, and particularly relates to a complete set of equipment for detecting the vertical pull-out bearing capacity of large-tonnage single piles without foundation pretreatment. Background Art

[0002] Pullout piles are widely used to prevent buoyancy in large basements, high-rise buildings, offshore platforms, anchor pile foundations for suspension and cable-stayed bridges, large dock slabs, and static load tests. These piles are driven to offset the upward buoyancy of soil water in construction projects where the underground structure is below the surrounding soil water level. The single-pile vertical pullout static load test device is a key component in testing reinforced concrete piles in construction projects. This test determines the ultimate pullout bearing capacity of a single pile and determines whether its vertical pullout bearing capacity meets design specifications.

[0003] Traditional steel bar welding pull-out tests lack specialized equipment. Instead, they rely on a single beam and a jack. A thick steel plate is placed on the jack, and multiple U-shaped steel bars are welded downward through the jack to the exposed rebar at the pile end (each U-shaped bar connects to two pile-end rebars). The lifting of the jack drives the thick steel plate upward, pulling the U-shaped bars. Because the U-shaped bars and the steel bars are already welded to the pile-end rebar, the pile-end rebar undergoes tensile testing. In existing single-pile vertical pull-out loading tests, the rebar extending from the pile must be individually welded or clamped, and then the pull-out force is applied via the jack's force-applying mechanism. This welding fixation method, on the one hand, requires welding and desoldering processes during the installation and disassembly processes of the pull-out platform, which consumes a lot of manpower and material resources, increases the test cost, and is not conducive to improving the test efficiency; on the other hand, due to the inconsistent diameters of the tested piles and the different diameters of the pile body steel cages, after welding with the existing process, in order to match the installation size of the reaction device, the stressed steel bars need to be bent inwards and outwards, which can easily cause local concentration of stress in the pile body during the test, resulting in damage to the pile head, and easily cause uneven stress on each steel bar, resulting in damage or desoldering of the stressed steel bars due to local tension, resulting in failure of the overall test.

[0004] Traditional rebar welding connections are easily limited by the working load of a single jack. The maximum test load for pullout tests can only reach 5000kN, which cannot meet the actual load requirements of existing cast-in-place pile pullout tests. In addition, because the base area of the support devices on the left and right sides of the pullout platform cannot be expanded, the test requires a high foundation bearing capacity, and the cost of foundation reinforcement is high. If the foundation in the test platform area has a weak underlying layer or improper reinforcement measures, the foundation bearing surface often settles excessively during the test, causing the jack to extend beyond normal operating conditions, resulting in ultimate test failure.

[0005] In addition, for the traditional method of clamping and fixing steel bars with anchor devices, it is required to configure fixtures for each steel bar separately. Due to the limited space between steel bars, the installation space of the fixtures is restricted. Without a suitable conversion component in the middle, it is impossible to achieve uniform force on the overall uplift resistance of the inspected pile.

[0006] For example, the Chinese utility model patent with the publication number CN213867973U discloses a pile foundation uplift detection device. When connecting the steel bars on the pile foundation, the connection between the steel bars in the pile to be tested and the multiple steel bars on the periphery of the connecting plate is achieved through welding. However, if there are bent parts on the steel bars of the pile to be tested, the steel bars on the pile to be tested need to be straightened first before welding with the multiple steel bars on the periphery of the connecting plate. In addition, after the uplift capacity test of the pile foundation is completed, the welded steel bars need to be sawed off or bent, which is likely to cause uneven force on each steel bar, with cumbersome operations and increased labor intensity of the staff. Therefore, it is necessary to provide a complete set of equipment for the large-tonnage single-pile vertical uplift bearing capacity detection without foundation pre-treatment, which is simple to operate, can expand the bearing area of the uplift platform, reduce the requirement for the foundation bearing capacity around the inspected pile, reduce the damage to the pile body, increase the allowable value of the maximum uplift test load, improve the accuracy of test data, and improve the installation and detection efficiency of uplift. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a complete set of equipment for the large-tonnage single-pile vertical uplift bearing capacity detection without foundation pre-treatment, which is simple to operate, can expand the bearing area of the uplift platform, reduce the requirement for the foundation bearing capacity around the inspected pile, reduce the damage to the pile body, increase the allowable value of the maximum uplift test load, improve the accuracy of test data, and improve the installation and detection efficiency of uplift.

[0008] The technical solution adopted by the present invention is as follows: The present invention includes an inspected pile, and longitudinal pile body steel bars are cast in the inspected pile. The complete set of equipment for the large-tonnage single-pile vertical uplift bearing capacity detection without foundation pre-treatment includes an upper reaction frame, a lower reaction frame, a plurality of sleeves, and a plurality of tool anchor devices. The lower reaction frame is provided with a plurality of first through holes in the vertical direction, and the upper parts of the plurality of longitudinal pile body steel bars are inserted into the first through holes. The tool anchor devices are arranged at the top of the lower reaction frame, and the tool anchor devices are in anchoring cooperation with the longitudinal pile body steel bars. The upper reaction frame is connected to the lower reaction frame through a plurality of 6m high-strength deformed bars. An external force applies a vertically upward pulling force to the upper reaction frame, so as to conduct an uplift test on the inspected pile.

[0009] As can be seen from the above solution, the reaction force lower frame is located directly below the reaction force upper frame. Through structural design optimization, the reaction force lower frame with outer, middle, and inner ring dimensions is fabricated to conform to the diameter dimensions of the steel cage of each inspected pile. The overall force is evenly distributed to the pile body of the inspected pile, reducing the occurrence of local stress concentration and significantly reducing the damage to the pile body caused by the detection process. The longitudinal steel bars of the pile body are anchored with the reaction force lower frame through tool anchors, thus replacing steel bar welding or threaded connection. During the installation process of the reaction force lower frame, through the adjustment of the tool anchors, the reaction force of the pile body is evenly distributed to each tensile steel bar, reducing the situation of damage caused by excessive local steel bar stress. The installation process of the platform does not require welding and unwelding processes, which is beneficial to improving the installation detection efficiency of uplift resistance. The advantages are obvious. This device can increase the allowable value of the maximum test load for uplift resistance and improve the accuracy of test data. Through the structural optimization of the equipment, different conversion devices are configured to adapt to various inspected piles, saving the time for making pile heads after pouring. Using the longitudinal steel bars of the pile body as the intermediate conversion reduces the installation difficulty and ensures safety. By changing the connection process, the reaction force lower frame and tool anchors are used as connection conversion tools to connect the inspected piles, which can save the time of traditional welding or threaded installation and is not limited by the connection height dimensions such as welding and threading, greatly improving the installation efficiency. The anchor is also a recyclable accessory, effectively reducing the supporting costs during installation.

[0010] One preferred solution is that with the center point of the reaction force lower frame as the center, the reaction force lower frame is provided with several circles of circular grooves with different radii, and the first through holes are evenly distributed on the arc surface of the circular grooves.

[0011] One preferred solution is that the complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without foundation pretreatment further includes an uplift main beam and two groups of jacks. Support piers are arranged on both the left and right sides of the inspected pile. The upper end of the support pier is provided with a support pier beam. The two groups of jacks are respectively arranged on the top of the corresponding support pier beams. The reaction force upper frame is arranged at the upper end of the uplift main beam, and the reaction force lower frame is arranged below the uplift main beam. The jacking end of the jack is in jacking cooperation with the bottom of the uplift main beam.

[0012] One preferred solution is that the support pier beam is 2 pieces of 12m × 6.5m × 1.5m (length × width × height), and the support piers are 4 pieces of 3.0m × 2.0m × 0.6m and 4 pieces of 4.0m × 2.0m × 0.6m. They are assembled to form a support base device with an area of 56 ㎡, which meets the bearing capacity characteristic value requirements of the uplift test under complex foundation conditions, eliminates the need for foundation pretreatment, reduces the site treatment cost, and ensures the safe and smooth completion of the test (for example, for an uplift test with a maximum bearing capacity of 10000 kN, the required uplift bearing capacity for the test is only about 119 kpa).

[0013] One preferred solution is that a number of vertically oriented second through-holes are provided in both the reaction force upper frame and the reaction force lower frame. A number of 6m precision rolled threaded steel bars are inserted into the corresponding second through-holes. A first nut is threadedly provided on the upper part of the 6m precision rolled threaded steel bar, and the first nut is located at the top of the reaction force upper frame. A second nut is threadedly provided on the lower part of the 6m precision rolled threaded steel bar, and the second nut is located at the bottom of the reaction force lower frame. According to the size of the longitudinal bars of the pile body, taking advantage of the full-thread characteristics of the precision rolled threaded steel, the height of the reaction force lower frame can be appropriately adjusted for easy installation.

[0014] One preferred solution is that both the reaction force upper frame and the reaction force lower frame are horizontally arranged. A number of the second through-holes are linearly distributed at the front and rear parts of the reaction force upper frame and the reaction force lower frame. The second through-holes of the reaction force upper frame and the second through-holes of the reaction force lower frame are vertically symmetric.

[0015] One preferred solution is that four groups of support bars are welded to the reaction force lower frame. The four groups of support bars are cross-connected and placed flat at the overhead part of the reaction force lower frame. The minimum included angle between adjacent support bars is 45 degrees. The four groups of support bars are interconnected to form a cross structure, and the circular groove is welded on the upper surface of the cross structure.

[0016] One preferred solution is that reinforcing plates are welded to both adjacent sides inside the reaction force lower frame, and the inclined support plate is welded to the middle of the reinforcing plate.

[0017] One preferred solution is that the several tool anchors are provided with different sizes and can cooperate with the longitudinal ordinary threaded steel bars of different nominal diameters of the pile body.

[0018] One preferred solution is that the several tool anchors can appropriately adjust the anchoring force position according to the position of the longitudinal ordinary threaded steel bar and the reaction force lower frame, so that the overall longitudinal ordinary threaded steel bar is uniformly stressed, avoiding the situation of steel bar failure caused by stress concentration during the test and resulting in test failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the structural schematic diagram of the present utility model;

[0020] Figure 2 is the top view of the reaction force lower frame;

[0021] Figure 3 is the top view of the reaction force upper frame;

[0022] Figure 4 is the structural schematic diagram of the present utility model applied to another scenario;

[0023] Figure 5 is the plan layout diagram of the pier beam and pier foundation Detailed implementation mode

[0024] As shown Figure 1 in the figure, in this embodiment, the utility model includes a pile under test 1, and the pile under test 1 is cast with longitudinal pile body steel bars 2. It is characterized in that: the complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without foundation pre-treatment includes a reaction force upper frame 3, a reaction force lower frame 4, and a number of tool anchors 5. The reaction force lower frame 4 is provided with a number of first through holes 6 in the vertical direction, and the longitudinal pile body steel bars 2 are inserted into the first through holes 6. The tool anchors 5 are arranged on the top of the reaction force lower frame 4, and the upper part of the longitudinal pile body steel bars 2 is anchored and matched with the tool anchors 5. The reaction force upper frame 3 is connected to the reaction force lower frame 4 through a number of 6m high-strength deformed steel bars 8. An external force applies a vertically upward pulling force to the reaction force upper frame 3, so as to conduct an uplift test on the pile under test 1. The reaction force lower frame 4 is located directly below the reaction force upper frame 3, and the pile under test 1 is located directly below the reaction force lower frame 4. The reaction force upper frame 3 is connected to the reaction force lower frame 4 through a number of the 6m high-strength deformed steel bars 8 to form an integral structure. The longitudinal pile body steel bars 2 are connected to the reaction force lower frame 4 through the tool anchors 5. When an external force applies a vertically upward pulling force to the reaction force upper frame 3, the 6m high-strength deformed steel bars 8 also apply a vertically upward pulling force to the longitudinal pile body steel bars 2, so as to conduct an uplift test on the pile under test 1. By adopting the anchoring method of tool anchors, the problem of low installation efficiency caused by welding or threads is effectively avoided. The reaction force lower frame 4 installs the longitudinal pile body steel bars 2 through the first through holes 6, and adjusts the position of the longitudinal pile body steel bars 2 in the reaction force lower frame 4 according to the diameter of the pile under test 1, so as to be compatible with the cage diameters of various specifications of the piles under test, and has good practicability.

[0025] As shown Figure 2 in the figure, in this embodiment, with the center point of the reaction force lower frame 4 as the center, the reaction force lower frame 4 is provided with a number of circular grooves 7 with different radii. The first through holes 6 are equidistantly distributed on the arc surface of the circular grooves 7. Each circle of the circular grooves 7 is provided with the first through holes 6 equidistantly distributed, and each circle of the first through holes 6 is adapted to the corresponding size of the pile under test 1. The staff adjusts the position of the longitudinal pile body steel bars 2 in the reaction force lower frame 4 according to the diameter of the pile under test 1, so as to be compatible with the cage diameters of each pile under test.

[0026] As shown Figure 1 and 5As shown, in this embodiment, the complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without foundation pre-treatment further includes an uplift main beam 9 and two groups of jacks 10. Pier supports 11 are arranged on both the left and right sides of the pile under test 1. A pier beam 12 is arranged at the upper end of the pier support 11. The two groups of jacks 10 are respectively arranged on the tops of the corresponding pier beams 12. The reaction upper frame 3 is arranged at the upper end of the uplift main beam 9, and the reaction lower frame 4 is arranged below the uplift main beam 9. The jacking end of the jack 10 is in jacking cooperation with the bottom of the uplift main beam 9. The pier support 11 and the pier beam 12 both play a role in supporting the uplift main beam 9. The jack 10 is used to jack up the uplift main beam 9, and the uplift main beam 9 is used to carry the reaction upper frame 3. The jack 10 drives the movable end to jack up, driving the reaction upper frame 3 to move upward. The reaction upper frame 3 is connected to the reaction lower frame 4 through a number of 6m fine rolled threaded steel bars 8 to form an integral structure. The reaction lower frame 4 is connected through the longitudinal reinforcement 2 of the pile body. Therefore, the longitudinal reinforcement 2 of the pile body is subjected to an upward pulling force, and thus the uplift test of the pile under test 1 is carried out. By expanding the stress surface size of the reaction upper frame 3 and optimizing the structural design, through the conversion of the uplift main beam 9, the original single-point stress in the middle of the jack 10 is converted into the combined stress on the left and right sides of the two jacks 10, thereby increasing the allowable value of the maximum uplift test load to 10,000 kN.

[0027] As Figure 2 and Figure 3 shown, in this embodiment, the reaction upper frame 3 and the reaction lower frame 4 are both provided with a number of vertical second through holes 13. A number of 6m fine rolled threaded steel bars 8 are inserted into the corresponding second through holes 13. The upper part of the 6m fine rolled threaded steel bar 8 is threaded with a first nut 15, and the first nut 15 is located at the top of the reaction upper frame 3. The lower part of the 6m fine rolled threaded steel bar 8 is threaded with a second nut 14, and the second nut 14 is located at the bottom of the reaction lower frame 4. Connecting the reaction upper frame 3 and the reaction lower frame 4 with the 6m fine rolled threaded steel bar 8, during the test process, the distance between the reaction upper frame 3 and the reaction lower frame 4 can be adjusted by adjusting the first nut 15 and the second nut 14, avoiding the situation of test failure caused by the elongation limit of the jack 12, thereby improving the accuracy of the test data.

[0028] As Figure 5As shown in the figure, in this embodiment, the abutment beam 12 is two beams with dimensions of 12m × 6.5m × 1.5m (length × width × height), and the abutments 11 are four with dimensions of 3.0m × 2.0m × 0.6m and four with dimensions of 4.0m × 2.0m × 0.6m. They are assembled to form a support base device with an area of 56 ㎡, meeting the bearing capacity characteristic value requirements of the uplift test under complex foundation conditions, eliminating the need for foundation pretreatment, reducing site treatment costs, and ensuring the safe and successful completion of the test (for example, for an uplift test with a maximum bearing capacity of 10,000 kN, the required uplift bearing capacity is only about 119 kPa).

[0029] As Figures 1 to 3 shown in the figure, in this embodiment, the upper reaction frame 3 and the lower reaction frame 4 are both arranged horizontally. A number of the second through holes 13 are distributed in a straight line at the front and rear of the upper reaction frame 3 and the lower reaction frame 4, and the second through holes of the upper reaction frame 3 are symmetrically arranged with those of the lower reaction frame 4 up and down. The uplift main beam 9 is arranged horizontally at the lower end of the upper reaction frame 3. A number of the second through holes 13 are distributed in a straight line at the front and rear of the upper reaction frame 3 and the lower reaction frame 4, providing a space for the arrangement of the uplift main beam 9.

[0030] As Figure 2 shown in the figure, in this embodiment, four groups of support plates 16 are welded to the lower reaction frame 4. The four groups of support plates 16 are cross - connected and placed flat at the overhead part of the lower reaction frame 4. The minimum included angle between adjacent support plates 16 is 45 degrees. The four groups of support plates 16 are connected to form a cross structure, and the circular groove 7 is welded to the upper surface of the cross structure. The support plates 16 are used to connect the circular groove 7. The four groups of support plates 16 are vertically and horizontally cross - connected to form a cross structure. On the one hand, it reduces the weight of the lower reaction frame 4, facilitating transportation. On the other hand, it is beneficial to improve the stability of the lower reaction frame 4.

[0031] As Figure 2 shown in the figure, in this embodiment, reinforcing plates 17 are welded to adjacent sides on the inner side of the lower reaction frame 4. The inclined support plates 16 are welded to the middle of the reinforcing plates 17. The reinforcing plates 17 and the adjacent sides on the inner side of the lower reaction frame 4 form a triangle, which is beneficial to improving the rigidity and strength of the overall structure of the lower reaction frame 4.

[0032] As Figure 4 shown in the figure, in this embodiment, a number of the abutments 11 are arranged side by side, increasing the support area of the entire device, and being applicable to the ground with poor flatness or relatively loose soil.

[0033] As Figures 1 to 4As shown, in this embodiment, several longitudinal steel bars 2 of the pile body are inserted into the first through holes 6 of the reaction lower frame 4, and the upper part of the longitudinal steel bars 2 of the pile body is anchored through a tool anchor 5 and cooperates with the upper part of the reaction lower frame 4, which can save the time of traditional welding or threaded installation, is not limited by the connection height dimensions such as welding and threading, and greatly improves the installation efficiency.

Claims

1. A complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without pre-treatment of the foundation, including the pile under test (1), and longitudinal steel bars (2) are cast in the pile under test (1), characterized in that: The complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without foundation pre-treatment further includes an upper reaction frame (3), a lower reaction frame (4), and several tool anchors (5). The lower reaction frame (4) is provided with several first through holes (6) in the vertical direction. The longitudinal steel bars (2) of the pile body are inserted into the first through holes (6). The tool anchors (5) are arranged at the top of the lower reaction frame (4). The upper part of the longitudinal steel bars (2) of the pile body is in anchoring cooperation with the tool anchors (5). The upper reaction frame (3) is connected to the lower reaction frame (4) through several 6m high-strength deformed bars (8). An external force applies a vertically upward pulling force to the upper reaction frame (3), so as to conduct an uplift test on the pile under test (1). With the center point of the lower reaction frame (4) as the center, the lower reaction frame (4) is provided with several circles of circular grooves (7) with different radii. The first through holes (6) are equidistantly distributed on the arc surface of the circular grooves (7). Each circle of the first through holes (6) is adapted to the size of the corresponding pile under test (1). The staff adjusts the position of the longitudinal steel bars (2) of the pile body on the lower reaction frame (4) according to the diameter of the pile under test (1), so as to be compatible with the diameter sizes of the steel reinforcement cages of each pile under test (1).

2. The complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without pre-treatment of the foundation according to claim 1, characterized in that: The complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without foundation pre-treatment further includes an uplift main beam (9) and two groups of jacks (10). Support piers (11) are arranged on both the left and right sides of the pile under test (1). The upper ends of the support piers (11) are provided with pier beams (12). The two groups of jacks (10) are respectively arranged on the tops of the corresponding pier beams (12). The upper reaction frame (3) is arranged at the upper end of the uplift main beam (9). The lower reaction frame (4) is arranged below the uplift main beam (9). The jacking ends of the jacks (10) are in jacking cooperation with the bottom of the uplift main beam (9).

3. The complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without foundation pre-treatment according to claim 2, characterized in that: Both the upper reaction frame (3) and the lower reaction frame (4) are provided with several second through holes (13) in the vertical direction. The several 6m high-strength deformed bars (8) are inserted into the corresponding second through holes (13). The upper part of the 6m high-strength deformed bar (8) is provided with a first nut (15) in a threaded manner. The first nut (15) is located at the top of the upper reaction frame (3). The lower part of the 6m high-strength deformed bar (8) is provided with a second nut (14) in a threaded manner. The second nut (14) is located at the bottom of the lower reaction frame (4).

4. The complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without pre-treatment of the foundation according to claim 3, characterized in that: The pier beams (12) are two with dimensions of 12m×6.5m×1.5m, and the support piers (11) are four with dimensions of 3.0m×2.0m×0.6m and four with dimensions of 4.0m×2.0m×0.6m. They are assembled to form a support base device with an area of 56㎡, meeting the bearing capacity characteristic value requirements of the uplift test under complex foundation conditions, without foundation pre-treatment, reducing the site treatment cost, and ensuring the safe and smooth completion of the test.

5. The complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without pre-treatment of the foundation according to claim 4, characterized in that: The upper reaction frame (3) and the lower reaction frame (4) are both horizontally arranged. A plurality of the second through holes (13) are linearly distributed at the front and rear parts of the upper reaction frame (3) and the lower reaction frame (4). The second through holes of the upper reaction frame (3) and the second through holes of the lower reaction frame (4) are vertically symmetric.

6. The complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without pre-treatment of the foundation, as claimed in claim 5, is characterized in that: Four groups of support plates (16) are welded to the lower reaction frame (4). The four groups of support plates (16) are cross-connected and placed flat at the overhead position of the lower reaction frame (4). The minimum included angle between adjacent support plates (16) is 45 degrees. The four groups of support plates (16) are connected to each other to form a cross structure. The circular groove (7) is welded to the upper surface of the cross structure.

7. The complete set of equipment for detecting the vertical uplift bearing capacity of large-tonnage single piles without pre-treatment of the foundation according to claim 6, characterized in that: Reinforcing plates (17) are welded to adjacent sides on the inner side of the lower reaction frame (4). The inclined support plates (16) are welded to the middle parts of the reinforcing plates (17).

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