A large-tonnage pile foundation static load test support pier bottom force transmission device

Abstract

This invention relates to a force transmission device at the bottom of a support pier for static load testing of large-tonnage pile foundations, belonging to the technical field of auxiliary equipment for stress and strain measurement in static load testing of geotechnical engineering. Through an overall structure of multiple stacked plates, adjacent rotating connections, and sequential linkage between the slider and the arc-shaped groove, when the device is not in operation, four rectangular bearing plates are stacked vertically. The occupied plane of the device is mainly determined by the outline of a single rectangular bearing plate, rather than always being equivalent to the large bearing area outline in the final working state. When the device is in operation, the four rectangular bearing plates can unfold sequentially under the constraints of adjacent connections and linkage, forming a larger bearing area, thus meeting the requirements of large-tonnage static load testing for bearing area. Rainwater or construction water can also be discharged outwards along the gaps, thereby improving the bottom venting and drainage conditions. The venting and drainage path is mainly formed by the boundaries between the plates, which helps to avoid a decrease in local stiffness and stress concentration caused by large-area openings.

Description

Technical Field

[0001] This invention belongs to the technical field of static load testing and force and stress measurement auxiliary equipment in geotechnical engineering, specifically relating to a force transmission device at the bottom of a support pier for static load testing of large-tonnage pile foundations. Background Technology

[0002] In the case of large-tonnage surcharge loading in the static load test of a single pile vertical compressive strength, it is necessary to apply vertical load to the test pile and the surrounding foundation through a surcharge platform, and evaluate the bearing state of the foundation by observing the changes in force, stress, and settlement response during the loading process. Currently, an integral bearing base is commonly used as the load transfer component between the surcharge platform and the foundation. This integral bearing base is generally a one-piece steel box structure with a continuous rectangular plane at its bottom. During use, the test site is first leveled and a sand and gravel cushion layer is laid. Then, the integral bearing base is hoisted onto the foundation, ensuring that its continuous bottom surface is in full contact with the foundation or cushion layer. This allows the large overall planar size to diffuse the large-tonnage pressure generated by the upper counterweight downwards and to transfer the load force more evenly to the foundation, thus providing the foundation bearing conditions for stress distribution evaluation and settlement observation in subsequent bearing capacity tests.

[0003] However, the aforementioned integral bearing base presents technical challenges in practical engineering due to its three structural features: a large, continuous bottom surface, and full contact with the foundation. Firstly, to meet the requirements of load diffusion and foundation stress control under heavy-duty conditions, the bearing base's planar dimensions must be large. However, the overall structure cannot be reduced in size when not in operation, making transportation, relocation, and hoisting inconvenient. Secondly, to ensure the pressure and stress transmission within the bearing area is as uniform as possible, existing technology requires a continuous, flat bottom surface that is fully in contact with the foundation. During loading, the underlying soil or gravel cushion is further compacted, reducing the original gap between the bottom surface and the foundation. Simultaneously, the base's perimeter encloses the internal area of ​​the bottom surface, making it difficult for outside air to freely enter. When the test results... When the upper load is released and the bearing base is lifted, the bottom surface cannot be instantly and completely separated from the foundation. Furthermore, the influx of outside air is delayed, easily leading to a localized low-pressure adsorption zone in the contact area. This significantly increases the lifting and separation resistance and can easily cause damage to the base edge and site disturbance. Secondly, since the bottom surface is a continuous and complete plane without any through channels, rainwater or construction water entering the bottom from the edge can only slowly seep out or remain along the perimeter. This retained water continuously infiltrates the foundation surface, altering soil strength and deformation parameters, causing unexpected changes in the foundation's bearing stress state during loading. This, in turn, affects the stability and reliability of force, stress, and settlement response data in pile foundation bearing capacity tests. Therefore, it is urgent to propose a force transmission device for the bottom of the support pier in static load tests of large-tonnage pile foundations. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, this invention provides a force transmission device at the bottom of a support pier for static load testing of large-tonnage pile foundations. This device solves the problems in existing large-tonnage static load tests where the integral bearing base is difficult to reduce the space occupied during transportation and hoisting, and where the continuous and complete bottom surface is in contact with the foundation, easily forming negative pressure adsorption after unloading, and the bottom air venting and drainage are not smooth.

[0005] The objective of this invention can be achieved through the following technical solutions: A force transmission device at the bottom of a support pier for static load testing of large-tonnage pile foundations includes a support section and a first rectangular bearing plate, a second rectangular bearing plate, a third rectangular bearing plate, and a fourth rectangular bearing plate stacked sequentially from top to bottom. The fourth rectangular bearing plate is rotatably connected to the support section. The first rectangular bearing plate is rotatably connected to the second rectangular bearing plate, the second rectangular bearing plate is rotatably connected to the third rectangular bearing plate, and the third rectangular bearing plate is rotatably connected to the fourth rectangular bearing plate. The upper surfaces of the second, third, and fourth rectangular bearing plates are respectively provided with a first 90° arc-shaped groove, a second 90° arc-shaped groove, and a third 90° arc-shaped groove. Each of the arc-shaped sliding grooves has a stop block at both ends. The lower surfaces of the first, second, and third rectangular pressure plates are respectively provided with a first slider, a second slider, and a third slider that slide in cooperation with the corresponding arc-shaped sliding groove. Each upper rectangular pressure plate has a 90° relative rotation stroke relative to the rectangular pressure plate below it, defined by the corresponding slider and the corresponding arc-shaped sliding groove. After the corresponding slider abuts against the corresponding stop block, it drives the rectangular pressure plate below it to rotate in linkage, so that the four rectangular pressure plates together form a pressure-bearing area in the unfolded state, and a gap communicating with the outside is formed between adjacent rectangular pressure plates.

[0006] As a further embodiment of the present invention, the first rectangular bearing plate, the second rectangular bearing plate, the third rectangular bearing plate and the fourth rectangular bearing plate are stacked and arranged in abutting position from top to bottom.

[0007] As a further embodiment of the present invention, the first 90° arc-shaped slide, the second 90° arc-shaped slide, and the third 90° arc-shaped slide all extend with the rotation center of the corresponding rotational connection as the center.

[0008] As a further aspect of the present invention, each stop block is located at both ends of the corresponding arc-shaped groove, which is used to limit the relative rotation angle between adjacent rectangular pressure plates to 90°.

[0009] As a further embodiment of the present invention, the first slider, the second slider and the third slider are respectively fixedly disposed on the lower surface of the corresponding upper rectangular pressure plate and extend into the corresponding arc-shaped groove.

[0010] As a further aspect of the present invention, the planar projections of the four rectangular bearing plates in the stacked state coincide with each other.

[0011] As a further embodiment of the present invention, the four rectangular pressure plates are arranged in a staggered manner in the unfolded state, and their planar projections together define a rectangular pressure-bearing area.

[0012] As a further aspect of the present invention, in the unfolded state, a height difference that varies sequentially along the vertical direction is formed between adjacent rectangular pressure plates.

[0013] As a further embodiment of the present invention, the height difference is equal to the thickness of the rectangular bearing plate.

[0014] As a further embodiment of the present invention, the gap between adjacent rectangular pressure plates extends to the outer edge of the pressure-bearing area to form an exhaust and drainage channel.

[0015] The beneficial effects of this invention are as follows: Compared with existing integral pressure-bearing bases, this invention achieves a larger pressure-bearing area without using a large integral flat plate by stacking and sequentially unfolding four rectangular pressure-bearing plates. This significantly reduces the space occupied during transportation, storage, and hoisting. The gaps between adjacent rectangular pressure-bearing plates, which connect to the outside and extend to the outer edges, prevent the formation of large closed cavities below the pressure-bearing area. This helps to reduce negative pressure adsorption after unloading and facilitates the timely drainage of rainwater or construction water. Through the coordinated cooperation of rotating connections, arc-shaped sliding grooves, sliders, and stops, each rectangular pressure-bearing plate can be unfolded in a predetermined angle and sequence without disassembling the plates into independent parts for on-site assembly. This improves the integrity and reusability of the system and helps ensure the consistency and stability of the unfolded state. Furthermore, through designs such as overlapping planar projections, rectangularization after unfolding, and controlled height differences, the invention also balances compact storage, regularity of the unfolded pressure-bearing area, and stable formation of gaps between plates. This makes it more suitable for repeated transport and multiple uses in large-tonnage static load testing scenarios. Attached Figure Description

[0016] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention in a stacked state; Figure 2 This is a schematic diagram of the first 90° arc-shaped groove structure of the present invention; Figure 3 This is a schematic diagram of the stop block structure of the present invention; Figure 4 This is a schematic diagram of the second rectangular pressure plate structure of the present invention.

[0018] Explanation of key component symbols: In the figure: 1. Support part; 2. First rectangular pressure plate; 3. Second rectangular pressure plate; 4. Third rectangular pressure plate; 5. Fourth rectangular pressure plate; 6. First 90° arc-shaped slide groove; 7. Second 90° arc-shaped slide groove; 8. Third 90° arc-shaped slide groove; 9. Stop block; 10. First slider; 11. Second slider; 12. Third slider. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0020] Please see Figure 1 - Figure 4 As shown, this embodiment provides a force transmission device at the bottom of a large-tonnage pile foundation static load test support, including a support part 1 and a first rectangular bearing plate 2, a second rectangular bearing plate 3, a third rectangular bearing plate 4, and a fourth rectangular bearing plate 5 stacked sequentially from top to bottom. The fourth rectangular bearing plate 5 is rotatably connected to the support part 1. The first rectangular bearing plate 2 is rotatably connected to the second rectangular bearing plate 3, the second rectangular bearing plate 3 is rotatably connected to the third rectangular bearing plate 4, and the third rectangular bearing plate 4 is rotatably connected to the fourth rectangular bearing plate 5. The upper surfaces of the second rectangular bearing plate 3, the third rectangular bearing plate 4, and the fourth rectangular bearing plate 5 are respectively provided with a first 90° arc-shaped groove 6, a second 90° arc-shaped groove 6, and a third 90° arc-shaped groove 6. The groove 7 and the third 90° arc-shaped slide 8 are provided with a stop block 9 at both ends of each arc-shaped slide. The lower surfaces of the first rectangular pressure plate 2, the second rectangular pressure plate 3 and the third rectangular pressure plate 4 are respectively provided with a first slider 10, a second slider 11 and a third slider 12 that slide in cooperation with the corresponding arc-shaped slide. Each upper rectangular pressure plate has a 90° relative rotation stroke relative to the rectangular pressure plate below it, which is defined by the corresponding slider and the corresponding arc-shaped slide. After the corresponding slider and the corresponding stop block abut, the rectangular pressure plate below it rotates in linkage, so that the four rectangular pressure plates together form a pressure-bearing area in the unfolded state, and a gap communicating with the outside is formed between adjacent rectangular pressure plates. To address the challenges of compact storage and transport of existing integral pressure-bearing bases in high-tonnage static load testing scenarios, the tendency for negative pressure adsorption after unloading due to the continuous, intact bottom surface adhering to the foundation, and the lack of effective venting and drainage paths at the bottom, this embodiment employs a multi-plate stacking and adjacent rotating connection, along with a sequential linkage between the slider and the arc-shaped groove. This structure divides the single large plane of the existing integral pressure-bearing base into multiple rectangular pressure plates that maintain an assembly relationship. When the device is not in operation, the four rectangular pressure plates are stacked vertically. The occupied area of ​​the device is primarily determined by the outline of each individual rectangular pressure plate, rather than always being equivalent to the large pressure-bearing outline in the final operating state. Therefore, transportation and storage... The space occupied during hoisting is significantly reduced. When the device is in operation, the four rectangular pressure plates can be sequentially unfolded under the constraints of adjacent connection and linkage, forming a large pressure-bearing area. This meets the requirements of large-tonnage static load tests for pressure-bearing area. At the same time, the adjacent rectangular pressure plates are not welded into a continuous, closed, integral bottom surface, but retain gaps that connect with the outside after unfolding. These gaps prevent the formation of a large, difficult-to-release closed cavity below the pressure-bearing area. During unloading and hoisting, outside air can enter along the gaps, which helps to weaken the negative pressure adsorption between the bottom surface and the foundation. Rainwater or construction water can also be discharged outwards along these gaps, thereby improving the bottom ventilation and drainage conditions. In addition, the ventilation and drainage path is mainly formed by the boundary between the plates, rather than by setting through weakening holes on the entire pressure plate. Therefore, it is beneficial to avoid the decrease in local stiffness and stress concentration of the plate caused by large-area openings.

[0021] It should be noted that the above design was adopted because, while directly making the pressure base into multiple separate, independent parts could reduce the size of each transported component, it would require on-site positioning, splicing, and alignment of each piece, resulting in poor overall integrity and a tendency for relative misalignment between the plates under heavy-duty conditions. If a single large flat plate structure were still used, the problems of large transport footprint, significant adhesion after unloading, and difficulties in venting and drainage would still exist. Therefore, an adjacent rotating connection method is used here to ensure that the multiple rectangular pressure plates maintain structural integrity while also allowing for folding and unfolding. The design employs a 90° arc-shaped groove, slider, and stop block to clearly limit the rotation trajectory, relative angle, and timing of the transmission of linkage force to the next level plate of the upper rectangular pressure plate. This ensures that each rectangular pressure plate can unfold in a predetermined order, avoiding problems such as insufficient or excessive rotation angle, mutual interference, or inconsistent final unfolding states. Furthermore, this design eliminates the need for a complex drive control system or exposed linkage mechanism, which simplifies the overall structure, improves operational stability, and balances the channel function between pressure plates with the compactness of the entire machine.

[0022] To further enhance storage stability and deployment consistency, based on the above embodiments, although the four rectangular pressure plates can be stacked vertically, unnecessary gaps between adjacent plates will increase the overall stacking height, raise the center of gravity, and cause collisions due to shaking during transportation and hoisting. This will also cause deviations in the initial relative positions of the slider and the arc-shaped groove, thus affecting the consistency of the deployment action. In one embodiment, the first rectangular pressure plate 2, the second rectangular pressure plate 3, the third rectangular pressure plate 4, and the fourth rectangular pressure plate 5 are arranged sequentially from top to bottom in the stacked state. This sequential arrangement results in a more stable initial relative position between adjacent rectangular pressure plates, a lower overall stacking height, and a more controllable center of gravity. This is beneficial for compact storage and ensuring that subsequent coordinated deployment starts from a unified initial position.

[0023] Furthermore, since the two adjacent rectangular pressure plates are connected by a rotation, their relative motion is essentially a circular motion around the rotation center. If the center of the arc-shaped groove is not the same as the actual rotation center, the slider will be subjected to additional lateral pressure during the movement, which can easily lead to jamming, increased wear, uneven movement, or even failure to reach the predetermined angle. In one embodiment, the first 90° arc-shaped groove 6, the second 90° arc-shaped groove 7, and the third 90° arc-shaped groove 8 all extend with the rotation center of the corresponding rotation connection as the center. After setting the arc-shaped groove to extend with the corresponding rotation center as the center, the movement trajectory of the slider in the groove is consistent with the actual relative movement trajectory between the adjacent plates, thereby making the guiding relationship more natural, the force more reasonable, and the movement more stable. It also helps to improve the reliability and service life of the linkage deployment mechanism. Therefore, this design is the key to ensuring the establishment of the kinematic matching relationship.

[0024] Although the arc-shaped slide can guide the slider, without clear end limits, the relative angle between adjacent rectangular pressure plates may still change due to external force, inertia, assembly errors, or operational differences. When the angle is insufficient, the pressure plate will not unfold properly, affecting the formation of the pressure area. When the angle is too large, plate interference, final state offset, or even affecting the smooth linkage of the next rectangular pressure plate may occur. In one embodiment, each stop 9 is located at both ends of the corresponding arc-shaped slide to limit the relative angle between adjacent rectangular pressure plates to 90°. By setting stop blocks at both ends of the arc-shaped slide, the starting boundary and the ending boundary of the relative rotation can be limited simultaneously, so that the relative angle between adjacent rectangular pressure plates is stabilized at 90°. This ensures that the final state of unfolding is consistent and facilitates the timely transmission of the movement of the upper rectangular pressure plate to the next plate, realizing sequential linkage and accurate final state positioning.

[0025] To further optimize the arrangement of the linkage mechanism, it is necessary to establish a linkage relationship between adjacent rectangular pressure plates that can guide and transmit linkage force at appropriate positions without significantly increasing the overall external profile of the machine. If exposed linkages, levers, or other mechanisms are used, it will not only increase the external dimensions of the device and affect stacking and storage, but also make it susceptible to collisions or soil intrusion during transportation and use. In one embodiment, the first slider 10, the second slider 11, and the third slider 12 are respectively fixedly installed on the lower surface of the corresponding upper rectangular pressure plate and extend into the corresponding arc-shaped groove. Fixing the sliders on the lower surface of the upper rectangular pressure plate and extending them into the arc-shaped groove on the lower rectangular pressure plate can form a compact embedded fit between adjacent plates. This facilitates the direct transmission of the movement of the upper plate to the lower plate and restricts the linkage structure within the space between adjacent plates, thereby balancing structural compactness, operational reliability, and overall protection.

[0026] Although the stacking of four rectangular pressure plates has been achieved, if the planar projections of each plate in the stacked state do not coincide, the device will still occupy a large outer dimension in the planar direction even after it is folded up. This will prevent the effective transformation from the working state to the compact transportation state. Moreover, the center of force and the outer contour center may deviate during hoisting, which is not conducive to stable transportation. In one embodiment, the planar projections of the four rectangular pressure plates in the stacked state coincide with each other. By making the planar projections of the four rectangular pressure plates in the stacked state coincide with each other, the outer contour in the folded state can be concentrated as much as possible, minimizing the space occupied during transportation and storage. At the same time, it makes it easier to unify the overall center of gravity and the outer shape center, which is beneficial to improving the stability of hoisting and handling.

[0027] While the four rectangular bearing plates can be unfolded to form a bearing area, if the planar shape of this bearing area is irregular, the correspondence between it and the upper loading platform or counterweight arrangement will deteriorate. Uneven stress distribution, local cantilever, or insufficient utilization of the effective bearing area are likely to occur at the edges. It is also not conducive to construction personnel quickly judging whether the unfolding is in place. In one embodiment, the four rectangular bearing plates are arranged in a staggered manner in the unfolded state, and their planar projections are collectively defined as a rectangular bearing area. By designing the four rectangular bearing plates to be arranged in a staggered manner after unfolding, and making their planar projections collectively defined as a rectangular bearing area, the overall shape after unfolding can be regularized, which is more conducive to matching with common rectangular loading areas and is also more conducive to the downward diffusion of loads along regular boundaries. Therefore, this design not only helps to improve the utilization rate of the effective bearing area, but also helps to enhance the identifiability and engineering adaptability in the unfolded state.

[0028] In the basic structure of the above embodiment, the four rectangular bearing plates are originally in different stacking levels. If they are unfolded only through adjacent rotation without adding an additional lifting and leveling mechanism, each rectangular bearing plate will objectively be in a different vertical level after unfolding. If this vertical level relationship is not clearly defined, edge interference may occur during unfolding, and the size of the gap between adjacent plates may be difficult to control due to the unstable height relationship. In one embodiment, in the unfolded state, a height difference that changes sequentially along the vertical direction is formed between adjacent rectangular bearing plates. By clarifying the height difference that changes sequentially along the vertical direction between adjacent rectangular bearing plates, the objective height relationship brought about by the stacking level is actually transformed into an orderly and usable structural relationship, so that the plates can be stably misaligned and collisions can be reduced during unfolding, and a stable geometric basis is provided for the formation of the gap between the plates. Therefore, this design is a standardized utilization of the spatial relationship existing in the stacked unfolding structure.

[0029] Furthermore, although the height difference is already clearly defined, if the value of the height difference is not further limited, the height difference may bring new problems due to the design value being too large or too small. When the height difference is too small, the adjacent rectangular pressure plates may experience edge friction or even local interference when folded or unfolded, and the gap between the plates is also unstable. When the height difference is too large, it will unnecessarily increase the overall hierarchical difference, which is not conducive to the compact structure of the pressure-bearing area. In one embodiment, the height difference is equal to the thickness of the rectangular pressure plate. Since the four rectangular pressure plates are stacked vertically in units of plate thickness, limiting the adjacent height difference after unfolding to the thickness of the rectangular pressure plate can make the hierarchical relationship after unfolding correspond one-to-one with the original geometric relationship when stacked. This is not only convenient for manufacturing and assembly, but also helps to ensure the consistency of the final unfolded state and the controllable gap size.

[0030] Furthermore, while a gap connecting to the outside has been formed between adjacent rectangular pressure plates, if this gap is limited to a local area and cannot extend to the outer edge of the pressure-bearing area, air and water may still remain trapped in the local blind cavity, making it difficult to truly achieve rapid air replenishment, pressure relief, and drainage. This limits the effectiveness of mitigating negative pressure adsorption and water retention problems. In one embodiment, the gap between adjacent rectangular pressure plates extends to the outer edge of the pressure-bearing area to form an exhaust and drainage channel. By extending the gap between the plates to the outer edge of the pressure-bearing area, air can directly enter or exit along this channel, and rainwater and construction water can also be smoothly discharged outwards along this channel. This truly transforms the gap between the plates into an effective ventilation and drainage channel. Furthermore, this channel utilizes the existing boundary relationship between adjacent pressure-bearing plates, eliminating the need to add drainage holes or guide holes to the plates. This helps to maintain the integrity of the pressure-bearing plate body while simplifying the structure. This design functionalizes and makes practical the gap between the plates.

[0031] In summary, the beneficial effects of the overall design of this invention are as follows: it does not simply divide the overall pressure-bearing base into several individual parts, but rather achieves a space-saving reduction in the folded state and forms a large and regular pressure-bearing area in the unfolded state through a multi-plate stacked structure that maintains the overall assembly relationship. Furthermore, it utilizes the controlled gaps between the plates to simultaneously perform the functions of venting, drainage, and reducing negative pressure adsorption. At the same time, by progressively limiting the stacking relationship, movement trajectory, corner limits, final unfolded state, and height difference relationship, this invention further enhances the structure from simply being able to unfold to being able to unfold stably, repeatedly, with predictable unfolded state, and with stable channel function. Therefore, it better meets the comprehensive requirements of large-tonnage static load testing equipment for reliability, reusability, and engineering convenience.

[0032] Working principle and usage process of this invention: When the device is in the retracted state, the first rectangular pressure plate 2, the second rectangular pressure plate 3, the third rectangular pressure plate 4, and the fourth rectangular pressure plate 5 are stacked from top to bottom. When a rotational force is applied to the uppermost first rectangular pressure plate 2, the first slider 10 slides along the first 90° arc-shaped groove 6, causing the first rectangular pressure plate 2 to rotate relative to the second rectangular pressure plate 3. When the first slider 10 moves to the corresponding stop 9 and abuts against it, the first rectangular pressure plate 2 continues to be subjected to rotational force, which is transmitted to the second rectangular pressure plate 3 via the stop 9. The second rectangular pressure plate 3 rotates relative to the third rectangular pressure plate 4. Then, the second slider 11 completes the guidance and limitation in the second 90° arc-shaped slide groove 7, and continues to drive the third rectangular pressure plate 4 to rotate after abutting against the stop block 9. Furthermore, the third slider 12 completes the corresponding guidance and limitation in the third 90° arc-shaped slide groove 8, and drives the fourth rectangular pressure plate 5 to rotate relative to the support part 1 after abutting against the stop block 9. In this way, the four rectangular pressure plates unfold in sequence and reach a stable final unfolding state under the predetermined angle limitation.

[0033] The usage process is as follows: During transportation, storage, or relocation, the device remains stacked and folded to reduce its footprint and hoisting profile. When setting up the test site, the device is hoisted to the predetermined position and then unfolded. The four rectangular pressure plates together form a large pressure-bearing area to receive the upper load and diffuse the load to the surrounding foundation. During the test loading phase, the gaps formed between adjacent rectangular pressure plates provide a path for air replenishment, pressure relief, and drainage at the bottom, reducing water accumulation and negative pressure adsorption caused by the closed ground. After the test unloading is completed, outside air can enter the area below the pressure-bearing area through the channels, which helps to reduce the separation resistance between the device and the foundation, facilitating hoisting, transportation, and reuse.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A force transmission device at the bottom of a support pier for static load testing of large-tonnage pile foundations, characterized in that, The system includes a support portion and a first rectangular bearing plate, a second rectangular bearing plate, a third rectangular bearing plate, and a fourth rectangular bearing plate stacked sequentially from top to bottom. The fourth rectangular bearing plate is rotatably connected to the support portion. The first rectangular bearing plate is rotatably connected to the second rectangular bearing plate, the second rectangular bearing plate is rotatably connected to the third rectangular bearing plate, and the third rectangular bearing plate is rotatably connected to the fourth rectangular bearing plate. The upper surfaces of the second rectangular bearing plate, the third rectangular bearing plate, and the fourth rectangular bearing plate are respectively provided with a first 90° arc-shaped groove, a second 90° arc-shaped groove, and a third 90° arc-shaped groove. Each arc-shaped groove has a stop block at both ends. The lower surfaces of the first rectangular bearing plate, the second rectangular bearing plate, and the third rectangular bearing plate are respectively provided with a first slider, a second slider, and a third slider that slide in cooperation with the corresponding arc-shaped groove. Each upper rectangular pressure plate has a 90° relative rotation stroke relative to the rectangular pressure plate below it, defined by the corresponding slider and the corresponding arc-shaped groove. After the corresponding slider and the corresponding stop block abut, the rectangular pressure plate below it rotates in linkage, so that the four rectangular pressure plates together form a pressure-bearing area in the unfolded state, and a gap communicating with the outside is formed between adjacent rectangular pressure plates.

2. The force transmission device at the bottom of a large-tonnage pile foundation static load test support according to claim 1, characterized in that, The first rectangular bearing plate, the second rectangular bearing plate, the third rectangular bearing plate and the fourth rectangular bearing plate are stacked and abutted against each other from top to bottom.

3. The force transmission device at the bottom of a large-tonnage pile foundation static load test support according to claim 1, characterized in that, The first 90° arc-shaped slide, the second 90° arc-shaped slide, and the third 90° arc-shaped slide all extend with the rotation center of their corresponding rotational connection as the center of their circle.

4. The force transmission device at the bottom of a large-tonnage pile foundation static load test support according to claim 1, characterized in that, Each stop is located at both ends of the corresponding arc-shaped groove, which is used to limit the relative rotation angle between adjacent rectangular pressure plates to 90°.

5. The force transmission device at the bottom of a large-tonnage pile foundation static load test support according to claim 1, characterized in that, The first slider, the second slider, and the third slider are respectively fixedly disposed on the lower surface of the corresponding upper rectangular pressure plate and extend into the corresponding arc-shaped groove.

6. The force transmission device at the bottom of a large-tonnage pile foundation static load test support according to claim 1, characterized in that, The planar projections of the four rectangular bearing plates in the stacked state coincide with each other.

7. The force transmission device at the bottom of a large-tonnage pile foundation static load test support according to claim 1, characterized in that, The four rectangular pressure plates are arranged in a staggered manner in the unfolded state, and their planar projections together define a rectangular pressure-bearing area.

8. The force transmission device at the bottom of a large-tonnage pile foundation static load test support according to claim 7, characterized in that, The adjacent rectangular bearing plates form a vertically varying height difference.

9. The force transmission device at the bottom of a large-tonnage pile foundation static load test support according to claim 8, characterized in that, The height difference is equal to the thickness of the rectangular bearing plate.

10. The force transmission device at the bottom of a large-tonnage pile foundation static load test support according to claim 7, characterized in that, The gap between adjacent rectangular pressure plates extends to the outer edge of the pressure-bearing area to form an exhaust and drainage channel.

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