Permanent steel casing pile foundation vertical bearing test device

Abstract

The utility model relates to a vertical bearing test device for a permanent steel casing pile foundation. The vertical bearing test device comprises a calibration device, a pile foundation fixing device, a displacement monitoring device, a loading device and an auxiliary supporting structure, a concrete mold is installed in the auxiliary supporting structure, and the pile foundation is fixed in the pile foundation concrete mold through a pile foundation fixing device. Pressure sensors are fixed to the two ends of the pile foundation, and the pile foundation is sleeved with a permanent steel casing. The top of the auxiliary supporting structure comprises a cross beam and a vertical beam; the calibration device comprises a vertical beam sliding rail guide frame which is connected to the guide rail in a sliding mode. The calibration device is connected between the cross beam and the vertical beam; the loading device is connected to the bottom end of the middle of the calibration device; a jack is arranged at the bottom of the loading device; the top of the displacement monitoring device is fixed to the bottom of the vertical beam sliding rail guide frame. The utility model has the beneficial effects that the bearing capacity is strong, and the stability is good; the pile foundation displacement monitoring is accurate; the loading process is high in controllability; construction is simple and efficient, and the prefabrication degree is high.

Description

Technical Field

[0001] This utility model relates to the field of pile foundation testing technology, and in particular to a vertical bearing capacity testing device for permanent steel casing pile foundations. Background Technology

[0002] Pile foundation testing is a crucial means of evaluating pile foundation performance. Through testing, various mechanical parameters of the pile foundation can be obtained, providing important information for engineering design and construction. However, existing pile foundation testing techniques have many problems. Traditional loading equipment has limited accuracy, making it difficult to accurately simulate the complex load conditions in actual engineering projects, resulting in significant deviations between test results and actual conditions. Regarding displacement monitoring, some monitoring instruments are not accurate enough and are greatly affected by external environmental interference, making it impossible to obtain real-time and accurate pile foundation displacement data. Moreover, the overall stability of the testing device is insufficient, and it is prone to shaking and deformation during loading, affecting the accuracy and safety of the test. These problems restrict the development of pile foundation testing technology, and there is an urgent need for a more advanced pile foundation testing device to solve them. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a vertical bearing capacity test device for permanent steel casing pile foundations.

[0004] This vertical bearing capacity testing device for permanent steel casing pile foundations includes: a calibration device, a pile foundation fixing device, a displacement monitoring device, a loading device, and an auxiliary support structure. A concrete mold is installed inside the auxiliary support structure, and the pile foundation is fixed inside the concrete mold by the pile foundation fixing device. Pressure sensors are fixed at both ends of the pile foundation, and a permanent steel casing is fitted externally. The top of the auxiliary support structure includes a horizontal beam and a vertical beam, with a slide rail on the top of the horizontal beam. The calibration device includes a vertical beam slide rail guide frame, which is slidably connected to the guide rail. The calibration device is connected between the horizontal beam and the vertical beam. The loading device is connected to the bottom of the calibration device. A jack is located at the bottom of the loading device, and the jack is coaxial with the pile foundation. The top of the displacement monitoring device is fixed to the bottom of the vertical beam slide rail guide frame.

[0005] Preferably, the calibration device includes a horizontal hydraulic rod, a vertical hydraulic rod, a laser emitter, a laser receiver, and a beam slide rail guide. The calibration device has symmetrically arranged horizontal and vertical hydraulic rod reaction supports at its four corners. Horizontal hydraulic rods are welded between the horizontal hydraulic rod reaction supports, and vertical hydraulic rods are welded between the vertical hydraulic rod reaction supports. The top of the beam slide rail guide has a grooved slide rail, and the vertical hydraulic rod reaction supports are slidably connected to the top of the beam slide rail guide via pulleys at the bottom. The laser emitter is mechanically fixed to the lower end of the jack, and the laser receiver is mechanically fixed to the top of the pressure sensor at the top of the pile foundation. Connecting steel plates connect the top of the beam slide rail guide and the bottom of the beam, and an extension screw connects between the connecting steel plates, with a nut fixed to the extension screw. The beam slide rail guide is fixedly connected to the beam via the connecting steel plates, the extension screw, and the nut.

[0006] Preferably, the pile foundation fixing device includes a pile foundation fixing device horizontal bar, a pile foundation fixing device vertical bar, and a pile foundation fixing device connecting rod; the pile foundation fixing device horizontal bar is provided with a tenon and mortise structure on one side connecting to the pile foundation fixing device vertical bar; the pile foundation fixing device vertical bar is provided with tenon and mortise structures at both ends; the pile foundation fixing device connecting rod is provided with tenon and mortise structures at both ends and a reserved hole for the pile foundation fixing device in the middle; the tenon and mortise structure is provided with grooves and protrusions.

[0007] Preferably, the displacement monitoring device includes a vertical displacement guide rod, a horizontal displacement guide rod, and a displacement sensor; the vertical displacement guide rod includes a lower structure and an upper structure; the upper structure is welded to the bottom of the vertical beam slide rail guide; the lower structure and the horizontal displacement guide rod are connected by bolts; and the displacement sensor is placed on both sides of the horizontal displacement guide rod.

[0008] Preferably, the auxiliary support structure includes a bottom steel plate, a first H-beam column, a second H-beam column, a third H-beam column, and a fourth H-beam column; the first H-beam column, the second H-beam column, the third H-beam column, and the fourth H-beam column are welded to the four corners of the bottom steel plate; the crossbeams are welded between the tops of the first H-beam column and the third H-beam column, and the second H-beam column and the fourth H-beam column, respectively; the vertical beams are welded between the tops of the first H-beam column and the second H-beam column, and the third H-beam column and the fourth H-beam column, respectively.

[0009] Preferably, the four sides of the concrete mold are connected with mold reinforcement crossbars.

[0010] Preferably, the loading device includes a vertical beam slide rail guide, a jack, and a jack reaction support; the vertical beam slide rail guide is connected to both sides of the vertical hydraulic rod reaction support; the jack reaction support is slidably connected between the vertical beam slide rail guide; and the jack is welded and fixed to the bottom of the jack reaction support.

[0011] Preferably, the connecting steel plate has openings at the four corners, and the extension screw is fixed through the holes; the slide rail is fixed to the crossbeam by the connecting steel plate, the extension screw, and the nut.

[0012] The beneficial effects of this utility model are:

[0013] 1) This device has strong load-bearing capacity and good stability: The auxiliary support structure is welded from a bottom steel plate, horizontal beams, vertical beams and multiple I-beam columns; the bottom steel plate can evenly distribute the upper load, so that the device can be placed stably; the horizontal beams and vertical beams form a grid frame, which enhances the resistance to lateral displacement, ensures the overall stability of the device during the test, has high strength load-bearing capacity, and meets the test requirements.

[0014] 2) This practical pile foundation displacement monitoring is accurate: The displacement monitoring device consists of a lower structure of the vertical rod of the displacement guide frame, an upper structure, a horizontal rod, and a displacement sensor; the vertical rod of the guide frame can be adjusted vertically and horizontally, and the displacement sensor is installed at key positions on both sides of the horizontal rod and can move left and right, so as to collect displacement data in real time; high-precision displacement sensors are selected and four displacement guide frames are set to reduce external interference, greatly improve the monitoring accuracy and reliability, and can accurately obtain pile foundation displacement change data.

[0015] 3) The loading process of this utility model is highly controllable: The loading device includes a vertical hydraulic rod, a horizontal beam guide rail, a jack, and a jack reaction support; the vertical hydraulic rod provides vertical loading force, and the horizontal hydraulic rod enables the jack to move horizontally, with the loading accuracy controlled within ±1%; the calibration device uses a laser transmitter, receiver, and hydraulic rod to ensure that the jack and the pile top axis are aligned, ensuring accurate transmission of loading force, accurately simulating actual engineering load conditions, and making the loading process controllable.

[0016] 4) This practical application is simple, efficient and highly prefabricated: the construction steps are clear, and components such as pile foundation fixing devices are connected by mortise and tenon structures to avoid the cracking of wooden boards caused by nails, which would damage the mold. It is also easy to install and disassemble. Some components can be prefabricated in advance and quickly assembled on site, which reduces construction time and difficulty, improves overall efficiency, and ensures the accuracy and reliability of the test. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall vertical bearing capacity test device for permanent steel casing pile foundations;

[0018] Figure 2 This is a 3D diagram of a permanent steel casing pile foundation fixing device;

[0019] Figure 3 This is a three-dimensional diagram of a permanent steel casing pile foundation test.

[0020] Figure 4 It is a 3D diagram of the slide rail guide frame;

[0021] Figure 5 This is a 3D diagram of the displacement monitoring device;

[0022] Figure 6 This is a schematic diagram of the displacement monitoring device installation.

[0023] Explanation of reference numerals in the attached drawings: 1. Vertical hydraulic rod; 2. Horizontal beam slide rail guide; 3. Jack; 4. Upper structure of the vertical rod of the displacement guide; 5. Laser emitter; 6. Lower structure of the vertical rod of the displacement guide; 7. Bolt; 8. Laser receiver; 9. Pressure sensor; 10. Permanent steel casing; 11. Pile foundation fixing device; 12. Horizontal rod of the pile foundation fixing device; 13. First I-beam column; 14. Mold reinforcement horizontal rod; 15. Concrete mold; 17. Vertical beam; 18. Second I-beam column; 19. Limiting device; 20. Bottom steel plate; 21. Vertical rod of the pile foundation fixing device; 22. Horizontal beam; 23. Mortise and tenon structure; 24. Displacement sensor; 25. Third I-beam column; 26. Nut; 27. Vertical rod of displacement guide frame; 28. Fourth I-beam column; 29. ​​Connecting steel plate; 30. Extended screw; 31. Lateral hydraulic rod reaction support; 32. Horizontal rod of displacement guide frame; 33. Jack reaction support; 34. Pulley; 35. Vertical hydraulic rod reaction support; 36. Pile foundation fixing device connecting rod; 37. Vertical beam slide rail guide frame; 38. Calibration device; 39. Displacement monitoring device; 40. Loading device; 41. Lateral hydraulic rod; 42. Pile foundation; 43. Auxiliary support structure; 44. Karst cave simulation material; 45. Bottom concrete; 46. Reserved hole for pile foundation fixing device. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that, for those skilled in the art, several modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0025] Example 1

[0026] As one embodiment, a vertical bearing capacity test device for permanent steel casing pile foundations is proposed, such as... Figures 1 to 6As shown, it includes: a calibration device 38, a pile foundation fixing device 11, a displacement monitoring device 39, a loading device 40, and an auxiliary support structure 43; a concrete mold 15 is installed inside the auxiliary support structure 43, and mold reinforcement crossbars 14 are connected to the four sides of the concrete mold 15. The pile foundation 42 is fixed inside the concrete mold 15 by the pile foundation fixing device 11; pressure sensors 9 are fixed at both ends of the pile foundation 42, and a permanent steel casing 10 is fitted on the outside; the top of the auxiliary support structure 43 includes a horizontal beam 22 and a vertical beam 17, and a slide rail is provided on the top of the horizontal beam 22; the calibration device 38 includes a vertical beam slide rail guide 37, and the vertical beam slide rail guide... The frame 37 is slidably connected to the guide rail; the calibration device 38 is connected between the crossbeam 22 and the vertical beam 17; the loading device 40 is connected to the bottom of the middle part of the calibration device 38; the bottom of the loading device 40 is equipped with a jack 3, which is coaxial with the pile foundation 42; the top of the displacement monitoring device 39 is fixed to the bottom of the vertical beam slide rail guide frame 37; the loading device 40 can provide accurate and stable loading force, and the jack 3 can meet different loading requirements; the displacement monitoring device 39 uses a displacement sensor 24 for monitoring, which improves the monitoring accuracy and reliability; the pile foundation fixing device 11 is reasonably designed, and through the coordinated action of multiple components, it stabilizes the pile foundation 42 and reduces test errors.

[0027] like Figure 1As shown, the calibration device 38 includes a horizontal hydraulic rod 41, a vertical hydraulic rod 1, a laser emitter 5, a laser receiver 8, and a crossbeam slide rail guide 2. The crossbeam slide rail guide 2 is made of wear-resistant steel with a surface hardness of HRC50-55, reducing slide rail wear, extending the service life of the device, and ensuring the long-term stable operation of the test device. The calibration device 38 has symmetrically arranged horizontal hydraulic rod reaction supports 31 and vertical hydraulic rod reaction supports 35 at its four corners. Horizontal hydraulic rods 41 are welded between the horizontal hydraulic rod reaction supports 31, and vertical hydraulic rods 1 are welded between the vertical hydraulic rod reaction supports 35. The top of the crossbeam slide rail guide 2 is provided with a grooved slide rail, and the vertical hydraulic rod reaction supports 35 are slidably connected to the top of the crossbeam slide rail guide 2 through pulleys 34 at the bottom. The laser emitter 5 is mechanically fixed to the lower end of the jack 3, and the laser receiver 8 is mechanically fixed to the pressure transmitter at the top of the pile foundation 42. The top of sensor 9 improves the loading accuracy of jack 3, ensuring that jack 3 and pile foundation 42 are on the same axis; the top of beam slide rail guide 2 and the bottom of beam 22 are connected by connecting steel plates 29, with openings at the four corners of connecting steel plates 29, through which extended screws 30 are fixed; the slide rail is fixed to beam 22 by connecting steel plates 29, extended screws 30, and nuts 26; extended screws 30 are connected between connecting steel plates 29, and nuts 26 are fixed to extended screws 30; beam slide rail guide 2 is fixed to beam 22 by connecting steel plates 29, extended screws 30, and nuts 26; calibration device 38 uses laser emitter 5, laser receiver 8, vertical hydraulic rod 1, and horizontal hydraulic rod 41 to ensure that the axis of jack 3 and the top of pile foundation 42 coincide, ensuring that the loading accuracy of the loading force is controlled within ±1%, ensuring the accuracy of the loading force, accurately simulating the actual engineering load conditions, and making the loading process controllable.

[0028] like Figure 2 As shown, the pile foundation fixing device 11 includes a pile foundation fixing device horizontal bar 12, a pile foundation fixing device vertical bar 21, and a pile foundation fixing device connecting rod 36; the pile foundation fixing device horizontal bar 12 is provided with a tenon and mortise structure 23 on one side connecting to the pile foundation fixing device vertical bar 21; the pile foundation fixing device vertical bar 21 is provided with tenon and mortise structures 23 at both ends; the pile foundation fixing device connecting rod 36 is provided with tenon and mortise structures 23 at both ends and a reserved hole 46 in the middle; the tenon and mortise structure 23 is provided with grooves and protrusions; the tenon and mortise structure 23 can prevent the pile foundation 42 from shifting and shaking during the test, ensuring the accuracy of the test results, and at the same time can avoid the wooden pile foundation fixing device 11 from cracking due to nails, which would damage the mold, and at the same time facilitates installation and disassembly.

[0029] Example 2

[0030] As another embodiment, this second embodiment proposes a more specific vertical bearing capacity test device for permanent steel casing pile foundation based on the first embodiment.

[0031] like Figure 1 , Figure 5 and Figure 6 As shown, the displacement monitoring device 39 includes a vertical displacement guide rod 27, a horizontal displacement guide rod 32, and a displacement sensor 24. The vertical displacement guide rod 27 includes a lower structure 6 and an upper structure 4. The upper structure 4 is welded to the bottom of the vertical beam slide rail guide 37. The lower structure 6 and the horizontal displacement guide rod 32 are connected by bolts 7. The lower structure 6 and the upper structure 4 can extend and retract vertically. The displacement sensor 24 is placed on both sides of the horizontal displacement guide rod 32 and can move left and right. The displacement sensor 24 is a high-precision sensor and is installed in a key position to collect displacement data in real time, thereby improving monitoring accuracy.

[0032] like Figure 1 As shown, the auxiliary support structure 43 includes a bottom steel plate 20, a first H-beam column 13, a second H-beam column 18, a third H-beam column 25, and a fourth H-beam column 28. The bottom steel plate 20 has the first H-beam column 13, the second H-beam column 18, the third H-beam column 25, and the fourth H-beam column 28 welded to its four corners. The bottom steel plate 20 serves as the foundation of the entire auxiliary support structure 43, evenly distributing the load transmitted from the upper structure and ensuring its stable placement on the ground or other supporting surfaces. It provides solid support and stability; the crossbeams 22 are welded between the tops of the first H-beam column 13 and the third H-beam column 25, the second H-beam column 18 and the fourth H-beam column 28 respectively; the vertical beams 17 are welded between the tops of the first H-beam column 13 and the second H-beam column 18, the third H-beam column 25 and the fourth H-beam column 28 respectively; the crossbeams 22 and the vertical beams 17 are connected to form a grid-like frame structure, and the two work together to enhance the lateral displacement resistance and stability of the entire structure.

[0033] like Figure 1 As shown, the loading device 40 includes a vertical beam slide rail guide 37, a jack 3, and a jack reaction support 33. The vertical beam slide rail guide 37 is connected to both sides of the vertical hydraulic rod reaction support 35. The vertical beam slide rail guide 37 is made of wear-resistant steel with a surface hardness of HRC50-55, which reduces slide rail wear, extends the service life of the device, and ensures the long-term stable operation of the test device. The jack reaction support 33 is slidably connected between the vertical beam slide rail guide 37. The jack 3 is welded and fixed to the bottom of the jack reaction support 33, which can perform additional vertical loading.

[0034] The test method for this permanent steel casing pile foundation vertical bearing capacity test device, such as... Figures 1 to 6 As shown, it includes the following steps:

[0035] Step 1: Grind the surface of the pile foundation 42 where strain gauges need to be attached to smooth the surface, attach the strain gauges to test the axial force data, and apply epoxy resin to the surface of the strain gauges. Fix the pressure sensor to the bottom of the pile foundation with waterproof tape, ensuring that the pressure sensor 9 is sealed. Attach the strain gauges to the corresponding positions on the surface of the permanent steel casing 10, place the pile foundation 42 inside the permanent steel casing 10, and fill the empty parts with epoxy resin.

[0036] Step 2, First pour: Make concrete mold 15 according to the size requirements. Reinforce the concrete mold 15 with mold reinforcement crossbars 14 around the concrete mold 15 to ensure that the concrete mold 15 will not burst when pouring the bottom concrete 45. Draw the height mark for the first pour on the bottom of the concrete mold 15 and place it on the base to pour the bottom concrete 45 for the first time.

[0037] Step 3, Second Pouring: Determine the preset position of pile foundation 42, and level the bottom concrete 45 on the surface of that position to ensure the bottom of pile foundation 42 is flat. Place pile foundation 42 in the pre-marked position and firmly fix it using pile foundation fixing device 11 to ensure that pile foundation 42 will not move left or right, effectively ensuring that pile foundation 42 will not shift its position when pouring bottom concrete 45. Fix pile foundation fixing device 11 using limiting device 19. Then pour bottom concrete 45;

[0038] Step 4: Install pressure sensor 9 on top of pile 42 to test the pressure of jack 3. Then, temporarily place laser receiver 8 on top of pressure sensor 9, and simultaneously install laser emitter 5 under jack 3. Use a motor to first move the horizontal hydraulic rod 41, then the vertical hydraulic rod 1. Feedback from laser receiver 8 confirms that jack 3 is aligned with the axis of pile 42. This ensures that the force from jack 3 is accurately transmitted to pile 42.

[0039] Step 5: Before formally starting the vertical bearing capacity test on pile foundation 42, disassemble laser transmitter 5 and laser receiver 8. Carefully connect all the wiring according to the established wiring plan. After connection, start the data system and perform comprehensive debugging. Conduct the vertical bearing capacity test on pile foundation 42.

[0040] It should be noted that the parts in this embodiment that are the same as or similar to those in Embodiment 1 can be referred to each other, and will not be repeated in this application.

[0041] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

Claims

1. A permanent steel-cased pile vertical bearing test device, characterized in that, The utility model relates to a calibration device, pile foundation fixing device, displacement monitoring device, loading device and auxiliary support structure. The auxiliary support structure is internally provided with a concrete mold, and the pile foundation is fixed in the pile foundation concrete mold through the pile foundation fixing device; pressure sensors are fixed at both ends of the pile foundation, and a permanent steel casing is externally sleeved; the top of the auxiliary support structure comprises a cross beam and a vertical beam, and the top of the cross beam is provided with sliding rails; the calibration device comprises a vertical beam sliding rail guide frame which is slidingly connected to the guide rail; the calibration device is connected between the cross beam and the vertical beam; the loading device is connected to the bottom of the middle part of the calibration device; the bottom of the loading device is provided with a jack, and the jack is coaxial with the pile foundation; the top of the displacement monitoring device is fixed to the bottom of the vertical beam sliding rail guide frame. The calibration device comprises a horizontal hydraulic rod, a vertical hydraulic rod, a laser emitter, a laser receiver and a cross beam sliding rail guide frame; horizontal hydraulic rod counterforce supports and vertical hydraulic rod counterforce supports are symmetrically arranged at the four corners of the calibration device; a horizontal hydraulic rod is welded between the horizontal hydraulic rod counterforce supports, and a vertical hydraulic rod is welded between the vertical hydraulic rod counterforce supports; the top of the cross beam sliding rail guide frame is provided with a groove sliding rail, and the vertical hydraulic rod counterforce supports are slidingly connected to the top of the cross beam sliding rail guide frame through the sliding pulleys arranged at the bottom; the laser emitter is fixed to the lower end of the jack through mechanical engagement, the laser receiver is fixed to the top of the pressure sensor at the top of the pile foundation through mechanical engagement, the top of the cross beam sliding rail guide frame and the bottom of the cross beam are connected with a connecting steel plate, the connecting steel plate is connected with an elongated screw, and the elongated screw is fixed with a nut; the cross beam sliding rail guide frame is fixedly connected to the cross beam through the connecting steel plate, the elongated screw and the nut.

2. The permanent steel-cased pile vertical load test apparatus according to claim 1, wherein The pile foundation fixing device comprises a pile foundation fixing device horizontal rod, a pile foundation fixing device vertical rod and a pile foundation fixing device connecting rod; the side of the pile foundation fixing device horizontal rod connected to the pile foundation fixing device vertical rod is provided with a mortise and tenon structure; the two ends of the pile foundation fixing device vertical rod are provided with mortise and tenon structures; the two ends of the pile foundation fixing device connecting rod are provided with mortise and tenon structures, and a pile foundation fixing device reserved hole is arranged in the middle; the mortise and tenon structure is provided with a groove and a protrusion; the mortise and tenon structure is made of wood.

3. The permanent steel-cased pile vertical load test apparatus according to claim 1, wherein The displacement monitoring device comprises a displacement guide frame vertical rod, a displacement guide frame horizontal rod and a displacement sensor; the displacement guide frame vertical rod comprises a displacement guide frame vertical rod lower structure and a displacement guide frame vertical rod upper structure; the displacement guide frame vertical rod upper structure is fixed to the bottom of the vertical beam sliding rail guide frame through welding; the displacement guide frame vertical rod lower structure and the displacement guide frame horizontal rod are connected through bolts; the displacement sensor is arranged on both sides of the displacement guide frame horizontal rod; the displacement guide frame vertical rod lower structure and the displacement guide frame vertical rod upper structure can be telescoped up and down.

4. The permanent steel-cased pile vertical load test apparatus according to claim 1, wherein The auxiliary support structure comprises a bottom steel plate, a first I-shaped steel stand, a second I-shaped steel stand, a third I-shaped steel stand and a fourth I-shaped steel stand; the four corners of the bottom steel plate are welded with the first I-shaped steel stand, the second I-shaped steel stand, the third I-shaped steel stand and the fourth I-shaped steel stand; the cross beam is respectively welded between the top of the first I-shaped steel stand and the third I-shaped steel stand and between the top of the second I-shaped steel stand and the fourth I-shaped steel stand; the vertical beam is respectively welded between the top of the first I-shaped steel stand and the second I-shaped steel stand and between the top of the third I-shaped steel stand and the fourth I-shaped steel stand.

5. The permanent steel-cased pile vertical load test apparatus according to claim 1, wherein The concrete mold is connected with a mold reinforcing horizontal rod around the side wall.

6. The permanent steel-cased pile vertical load test apparatus according to claim 1, wherein ​ 7. A permanent steel-cased pile vertical load test apparatus according to claim 1 or claim 2, characterised in that, The loading device comprises a vertical beam sliding rail guide frame, a jack and a jack counterforce support; the vertical beam sliding rail guide frame is connected on both sides of the vertical hydraulic rod counterforce support; the jack counterforce support is slidingly connected between the vertical beam sliding rail guide frame; and the jack is welded and fixed at the bottom of the jack counterforce support.

8. The permanent steel-cased pile vertical load test apparatus according to claim 2, wherein The four corners of the connecting steel plate are provided with openings, and the lengthened screw rod is fixedly penetrated in the openings; and the sliding rail is fixed on the cross beam through the connecting steel plate, the lengthened screw rod and the nut.

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