Device for detecting anti-torsion bearing capacity of offshore pile foundation

Abstract

An offshore pile foundation anti-torsion bearing capacity detection device at least comprises a first loading unit, a second loading unit and a monitoring unit, and the first loading unit comprises a first stress plate, a first steel lever, a first steel force application beam, a first steel force transmission beam, a first self-adaptive fulcrum, a first anti-overturning spiral pile and a first servo motor; the first steel lever is installed on the first anti-overturning spiral pile, and one side of the short arm end of the first steel lever is in rigid connection with the first stress plate through the first steel force application beam. The other side of the long arm end is connected with a first servo motor through a first steel force transmission beam; the second loading unit and the first loading unit are symmetrically arranged relative to the center of the test pile; the monitoring unit comprises a first digital dynamometer, a second digital dynamometer and a holder laser range finder. According to the device, nondestructive testing, test object self-adaption and loading size and position self-adaption of the anti-torsion bearing capacity of the offshore pile foundation can be achieved, construction is convenient and efficient, the detection device can be repeatedly used, and the engineering economy is further saved.

Description

Technical Field

[0001] This utility model belongs to the field of marine pile foundation bearing capacity testing, specifically relating to a marine pile foundation torsional bearing capacity testing device, which is suitable for testing the torsional bearing capacity of marine pile foundations and evaluating the ultimate bearing capacity of pile foundations. Background Technology

[0002] Offshore pile foundations, as a type of infrastructure, are widely used in marine engineering structures, such as oil drilling platforms, offshore wind farms, and cross-sea bridges. These structures often need to withstand complex loads such as wind, waves, and currents. Compared to ordinary engineering projects, horizontal loads in these projects are often transferred to the pile foundations in the form of eccentric loads, causing the pile foundations to also bear torque. Furthermore, the torque load on these foundations can increase to a maximum value at a certain instant, making pile foundations designed to ignore torque loads inherently unsafe. Therefore, ensuring that offshore pile foundations possess sufficient torsional bearing capacity is crucial for guaranteeing the safety and functionality of marine structures. Accurate testing of torsional bearing capacity can prevent structural failure, avoid potential economic losses and environmental risks, and provide data support for structural maintenance and reinforcement.

[0003] Currently, testing the torsional bearing capacity of offshore pile foundations faces numerous challenges. Traditional testing techniques typically involve destructive testing or require the installation of complex sensor networks. The former may damage the pile structure and affect its subsequent use, while the latter is costly and difficult to implement. Furthermore, due to the harshness of the marine environment, the maintenance and calibration of testing equipment are often difficult, affecting the routine execution of tests and the reliability of results. Moreover, most testing methods do not consider the fatigue damage that may occur in offshore pile foundations during long-term operation, making it impossible to effectively assess the degradation of their torsional bearing capacity.

[0004] In summary, current methods for testing the torsional bearing capacity of marine pile foundations need improvement in several aspects, including operability, cost-effectiveness, real-time performance, and accuracy. Therefore, developing a novel device and method for testing the torsional bearing capacity of marine pile foundations, capable of more accurately and efficiently assessing and monitoring the torsional performance of pile foundations in actual marine environments, thereby providing strong support for engineering design, construction, maintenance, and management, is a pressing technical challenge that needs to be addressed by those skilled in the art. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to provide a marine pile foundation torsional bearing capacity testing device to address the above-mentioned shortcomings of existing pile foundation bearing capacity testing methods. This device can realize non-destructive testing of marine pile foundation torsional bearing capacity, and the test object and loading size and position are adaptive. It is convenient and efficient to construct, and the testing device can be reused, further saving engineering costs.

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows:

[0007] A device for testing the torsional bearing capacity of marine pile foundations, comprising at least a first loading unit, a second loading unit, and a monitoring unit;

[0008] The first loading unit includes a first force-bearing plate, a first steel lever, a first steel force-applying beam, a first steel force-transmitting beam, a first adaptive fulcrum, a first ball bearing hoop system, a first anti-overturning helical pile, a first connecting crossbeam, a first high-strength steel cable, and a first servo motor. The first anti-overturning helical pile is driven into the water, the first connecting crossbeam is connected to the first anti-overturning helical pile, and the first steel lever is installed on the first anti-overturning helical pile through the first adaptive fulcrum and the first ball bearing hoop system. The first steel lever is divided into a first long arm end and a first short arm end of different lengths with the first adaptive fulcrum as the center. One side of the first short arm end is rigidly connected to one end of the first steel force-applying beam, and the other end of the first steel force-applying beam is rigidly connected to the first force-bearing plate. The other side of the first long arm end (the side opposite to the side of the first short arm end connected to the first steel force-applying beam) is connected to the first servo motor through the first steel force-transmitting beam and the first high-strength steel cable.

[0009] The second loading unit includes a second force-bearing plate, a second steel lever, a second steel force-applying beam, a second steel force-transmitting beam, a second adaptive fulcrum, a second ball bearing hoop system, a second anti-overturning helical pile, a second connecting crossbeam, a second high-strength steel cable, and a second servo motor. The second anti-overturning helical pile is driven into the water, and the second connecting crossbeam is connected to the second anti-overturning helical pile. The second steel lever is installed on the second anti-overturning helical pile via the second adaptive fulcrum and the second ball bearing hoop system. The second steel lever is divided into a second long arm and a second short arm of different lengths, centered on the second adaptive fulcrum. One side of the second short arm is rigidly connected to one end of the second steel force-applying beam, and the other end of the second steel force-applying beam is rigidly connected to the second force-bearing plate. The other side of the second long arm (opposite to the side of the second short arm connected to the second steel force-applying beam) is connected to the second servo motor via the second steel force-transmitting beam and the second high-strength steel cable. The first force-bearing plate and the second force-bearing plate are symmetrically welded to the outer wall of the test pile.

[0010] The monitoring unit includes a first digital force gauge, a second digital force gauge, and a gimbal laser rangefinder. The first digital force gauge is fixed on the first steel force-applying beam and is used to measure the axial force of the first steel force-applying beam. The second digital force gauge is fixed on the second steel force-applying beam and is used to measure the axial force of the second steel force-applying beam (and, combined with the distance between the first and second force-bearing plates, to calculate the torque on the test pile). The gimbal laser rangefinder is fixed on the first connecting crossbeam and is used for non-contact monitoring of the deformation and displacement of the test pile.

[0011] According to the above scheme, the first stress plate and the second stress plate are each welded from two steel plates with an included angle of 30~60°, the openings facing the outer wall of the test pile, and vertically welded to the outer wall of the test pile. One of the steel plates is perpendicular to the tangent at the welding point. The first stress plate and the second stress plate are on the same horizontal line, and the line connecting the first stress plate and the steel plate on the second stress plate that is perpendicular to the tangent at the welding point passes through the center of the test pile.

[0012] According to the above scheme, both the first anti-overturning helical pile and the second anti-overturning helical pile are formed by adding a large-diameter anti-overturning helical blade to the upper part of the helical pile. There are 1 to 3 first anti-overturning helical piles and 3 second anti-overturning helical piles. Each first anti-overturning helical pile is connected together by a first connecting crossbeam, and each second anti-overturning helical pile is connected together by a second connecting crossbeam.

[0013] According to the above scheme, the first ball bearing ring system and the second ball bearing ring system are ring systems composed of balls. The first ball bearing ring system restricts the first steel lever to rotate freely in the loading plane only with the first adaptive fulcrum as the center. The second ball bearing ring system restricts the second steel lever to rotate freely in the loading plane only with the second adaptive fulcrum as the center.

[0014] According to the above scheme, the first steel lever and the second steel lever are made of high-quality alloy steel plates, and their shape is an arc-shaped structure with a wider short arm end and a narrower long arm end.

[0015] According to the above scheme, the first steel force-applying beam, the second steel force-applying beam, the first steel force-transmitting beam, and the first steel force-transmitting beam are made of high-quality alloy steel plates. The steel plates are relatively long and narrow, and are in the shape of long strips.

[0016] According to the above scheme, the first steel force-applying beam and the first steel force-transmitting beam are both at 90° to the first steel lever as a whole; the second steel force-applying beam and the second steel force-transmitting beam are both at 90° to the second steel lever as a whole.

[0017] The working principle of this utility model is as follows: During the test, the first servo motor and the second servo motor are simultaneously activated to provide tension to the first and second high-strength steel cables, respectively. Under the action of the force, the first and second steel levers will rotate, thereby causing the first and second steel force-applying beams to generate horizontal thrust on the first and second load-bearing plates, respectively, causing the test pile to rotate. Gradual loading is performed, and the axial force of the first and second steel force-applying beams measured by the first force gauge and the axial force of the second steel force-applying beam measured by the second force gauge, as well as the distance of the test point measured by the gimbal laser rangefinder, are recorded under each load level. The torque and rotation angle under each loading condition are calculated, and the torque-rotation angle curve is plotted and analyzed to evaluate the ultimate torsional bearing capacity of the pile foundation, thus completing the torsional bearing capacity test of the marine pile foundation.

[0018] Compared with the prior art, the beneficial effects of this utility model are: the detection device will not damage the pile foundation, can realize non-destructive testing without affecting the subsequent service of the pile foundation, and does not require the installation of a complex sensor network, thus reducing the detection cost. At the same time, the overall device structure is simple and easy to operate, the test object is adaptive, the loading size and position are adaptive, the construction is convenient and efficient, and the detection device can be reused, with great prospects for promotion and social benefits. Attached Figure Description

[0019] Figure 1 This is an overall schematic diagram of the novel marine pile foundation torsional bearing capacity testing device of the present invention;

[0020] Figure 2 This is an overall top view of the novel marine pile foundation torsional bearing capacity testing device of the present invention;

[0021] Figure 3 This is a partial top view of the first and second force-bearing plates of the present invention;

[0022] Figure 4 This is a schematic diagram of the structure of a single anti-overturning helical pile in this invention;

[0023] Figure 5 This is a schematic diagram of the adaptive lever arm in this invention;

[0024] Figure 6 This is a schematic diagram of the fulcrum ball ring system in this invention;

[0025] In the diagram: 1-Test pile, 2-First steel lever, 3-First steel force-applying beam, 4-First steel force-transmitting beam, 5-First adaptive fulcrum, 6-First ball bearing hoop system, 7-First anti-overturning helical pile, 8-First connecting crossbeam, 9-First high-strength steel cable, 10-First servo motor, 11-First digital force gauge, 12-Second steel lever, 13-Second steel force-applying beam, 14-Second steel force-transmitting beam, 15-Second adaptive fulcrum, 16-Second ball bearing hoop system, 17-Second anti-overturning helical pile, 18-Second connecting crossbeam, 19-Second high-strength steel cable, 20-Second servo motor, 21-Second digital force gauge, 22-Pan-and-shoot laser rangefinder, 23-First load-bearing plate, 24-Second load-bearing plate. Detailed Implementation

[0026] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0027] like Figure 1-6 As shown, the marine pile foundation torsional bearing capacity testing device of this utility model includes a first loading unit, a second loading unit, and a monitoring unit;

[0028] The first loading unit includes a first load-bearing plate 23, a first steel lever 2, a first steel force-applying beam 3, a first steel force-transmitting beam 4, a first adaptive fulcrum 5, a first ball bearing hoop system 6, a first anti-overturning helical pile 7, a first connecting crossbeam 8, a first high-strength steel cable 9, and a first servo motor 10. The first anti-overturning helical piles 7 are driven into the water, each consisting of a helical pile with a large-diameter anti-overturning helical blade added to its upper part. One to three of these are installed. All the first anti-overturning helical piles 7 are connected together via the first connecting crossbeam 8 to form the foundation of the first anti-overturning helical pile. The first steel lever 2 is installed on the first anti-overturning helical pile via the first adaptive fulcrum 5 and the first ball bearing hoop system 6. On the overturning helical pile foundation, the first ball bearing hoop system 6 can reduce rotational friction while restricting the first steel lever 2 to rotate only in the horizontal plane around the first adaptive fulcrum 5. The first steel lever 2 is divided into a first long arm end and a first short arm end of different lengths around the first adaptive fulcrum 5. One side of the first short arm end is rigidly connected to one end of the first steel force-applying beam 3, and the other end of the first steel force-applying beam 3 is rigidly connected to the first force-bearing plate 23. The other side of the first long arm end (opposite to the side of the first short arm end connected to the first steel force-applying beam 3) is connected to the first servo motor 10 through the first steel force transmission beam 4 and the first high-strength steel cable 9.

[0029] The second loading unit includes a second force-bearing plate 24, a second steel lever 12, a second steel force-applying beam 13, a second steel force-transmitting beam 14, a second adaptive fulcrum 15, a second ball bearing hoop system 16, a second anti-overturning helical pile 17, a second connecting crossbeam 18, a second high-strength steel cable 19, and a second servo motor 20. The second anti-overturning helical piles 17 are driven into the water and are formed by adding a large-diameter anti-overturning helical blade to the upper part of the helical pile. One to three of these are installed. The second anti-overturning helical piles 17 are connected together by the second connecting crossbeam 18 to form the foundation of the second anti-overturning helical pile. The second steel lever 12 is installed on the foundation of the second anti-overturning helical pile via the second adaptive fulcrum 15 and the second ball bearing hoop system 16. The second ball bearing hoop system 16 reduces rotational friction while restricting the second steel lever 12 to rotate only in the horizontal plane around the second adaptive fulcrum 15. The second steel lever 12 is centered on the second adaptive fulcrum 15. The test pile consists of a second long arm and a second short arm of different lengths. The second short arm is rigidly connected to one end of the second steel force-applying beam 13, and the other end of the second steel force-applying beam 13 is rigidly connected to the second force-bearing plate 24. The other side of the second long arm (opposite to the side where the second short arm is connected to the second steel force-applying beam 13) is connected to the second servo motor 20 via the second steel force transmission beam 14 and the second high-strength steel cable 19. The first force-bearing plate 23 and the second force-bearing plate 24 are symmetrically welded to the outer wall of the test pile. The first force-bearing plate 23 and the second force-bearing plate 24 are each welded from two steel plates with an included angle of 45°. The openings face the outer wall of the test pile 1 and are vertically welded to the outer wall of the test pile 1. One of the steel plates is perpendicular to the tangent at the welding point. The first force-bearing plate 23 and the second force-bearing plate 24 are on the same horizontal line, and the line connecting the steel plates on the first force-bearing plate 23 and the second force-bearing plate 24 that are perpendicular to the tangent at the welding point passes through the center of the test pile 1. Figure 3 As shown.

[0030] The first steel lever 2 and the second steel lever 12 are made of high-quality alloy steel plates, and their shape is an arc-shaped structure with a wider short arm end and a narrower long arm end.

[0031] The first steel force-applying beam 3, the second steel force-applying beam 13, the first steel force-transmitting beam 4, and the first steel force-transmitting beam 14 are made of high-quality alloy steel plates. The steel plates are relatively long and narrow, and are in the shape of long strips.

[0032] The first steel force-applying beam 3 and the first steel force-transmitting beam 4 are both at 90° to the first steel lever 2; the second steel force-applying beam 13 and the second steel force-transmitting beam 14 are both at 90° to the second steel lever 12.

[0033] The monitoring unit includes a first digital force gauge 11, a second digital force gauge 21, and a gimbal laser rangefinder 22. The first digital force gauge 11 is fixed on the first steel force-applying beam 3 and is used to measure the axial force of the first steel force-applying beam 3. The second digital force gauge 21 is fixed on the second steel force-applying beam 13 and is used to measure the axial force of the second steel force-applying beam 13 (and, combined with the distance between the first force-bearing plate 23 and the second force-bearing plate 24, the torque on the test pile 1 is calculated). The gimbal laser rangefinder 22 is fixed on the first connecting crossbeam 8 and is used for non-contact monitoring of the deformation and displacement of the test pile. It features high precision and fast response. Utilizing the principle of laser triangulation, a visible red laser is directed towards the test point marked on the outer wall of the test pile. The reflected laser light passes through the receiver lens and is received by the internal CCD camera. The distance between the instrument and the test point is processed and analyzed by digital circuitry. Based on the distance between the instrument and the center of the test pile, the rotation angle of the test point can be obtained after post-processing, which is the rotation angle of the test pile 1. The gimbal's anti-shake system provides a stable support platform for the laser rangefinder, ensuring that the digital laser rangefinder is not affected by fluctuations in water flow, wind, etc., during measurement, thereby improving the stability and accuracy of the measurement. At this point, the torque and rotation angle experienced by test pile 1 are measured, and a curve showing the relationship between the rotation angle and the applied torque is plotted. Changes in the curve are used to determine whether failure has occurred and to evaluate its torsional bearing capacity.

[0034] The present invention relates to a method for testing the torsional bearing capacity of marine pile foundations using a marine pile foundation torsional bearing capacity testing device, comprising the following steps:

[0035] (1) Preliminary preparation: According to the project requirements, survey and select the test site, design the test plan and corresponding test equipment according to the specifications of the test piles to be tested and the bearing capacity requirements, and prefabricate and prepare the corresponding test piles 1, first force plate 23, second force plate 24, first steel lever 2, second steel lever 12, first steel force beam 3, second steel force beam 13, first steel force transmission beam 4, second steel force transmission beam 14, first ball ring hoop system 6, second ball ring hoop system 16, first anti-overturning spiral pile 7, second anti-overturning spiral pile 17, first connecting crossbeam 8, second connecting crossbeam 18, first high-strength steel cable 9, second high-strength steel cable 19, first servo motor 10, second servo motor 20, first digital force gauge 11, second digital force gauge 21, and gimbal laser rangefinder 22;

[0036] (2) On-site setup: Transport the testing device to the vicinity of the sea area of ​​the test pile 1. First, drive the test pile 1. During the driving process, keep the pile body vertical and the inclination within the allowable range of the project. Then, at a distance of 2-4 times the pile diameter from the test pile, install the first anti-overturning spiral pile 7 and the second anti-overturning spiral pile 17. Erect the first steel lever 2 and the second steel lever 12, the first connecting crossbeam 8 and the second connecting crossbeam 18, the first steel force beam 3, the second steel force beam 13, the first steel force transmission beam 4, the second steel force transmission beam 14, the first steel high-strength cable 9, the second steel high-strength cable 19, the first servo motor 10, and the second servo motor 20. Deploy the first digital force gauge 11, the second digital force gauge 21, and the gimbal laser rangefinder 22.

[0037] (3) Graded loading test: By simultaneously starting the first servo motor 10 and the second servo motor 20, the load is gradually graded. At the same time, the axial force of the first steel force beam 3 measured by the first digital force gauge 11 and the axial force of the second steel force beam 13 measured by the second digital force gauge 21, as well as the distance of the test point measured by the gimbal laser rangefinder 22, are recorded under each load level.

[0038] (4) Follow-up work: After the experiment, the detection device was recovered, the test data was processed, the torque and rotation angle under each loading condition were calculated, the torque-rotation angle curve was plotted and analyzed, the ultimate torsional bearing capacity of the pile foundation was evaluated, and the torsional bearing capacity test of the marine pile foundation was completed.

[0039] This utility model is not limited to the applications listed in the specification and embodiments. For those skilled in the art, various corresponding changes and modifications can be made based on this utility model, and all such changes and modifications fall within the protection scope of the claims of this invention.

Claims

1. A device for testing the torsional bearing capacity of marine pile foundations, characterized in that: It includes at least a first loading unit, a second loading unit, and a monitoring unit; The first loading unit includes a first force-bearing plate, a first steel lever, a first steel force-applying beam, a first steel force-transmitting beam, a first adaptive fulcrum, a first ball bearing hoop system, a first anti-overturning helical pile, a first connecting crossbeam, a first high-strength steel cable, and a first servo motor. The first anti-overturning helical pile is driven into the water, the first connecting crossbeam is connected to the first anti-overturning helical pile, and the first steel lever is installed on the first anti-overturning helical pile through the first adaptive fulcrum and the first ball bearing hoop system. The first steel lever is divided into a first long arm end and a first short arm end of different lengths with the first adaptive fulcrum as the center. One side of the first short arm end is rigidly connected to one end of the first steel force-applying beam, and the other end of the first steel force-applying beam is rigidly connected to the first force-bearing plate. The other side of the first long arm end is connected to the first servo motor through the first steel force-transmitting beam and the first high-strength steel cable. The second loading unit includes a second force-bearing plate, a second steel lever, a second steel force-applying beam, a second steel force-transmitting beam, a second adaptive fulcrum, a second ball bearing hoop system, a second anti-overturning helical pile, a second connecting crossbeam, a second high-strength steel cable, and a second servo motor. The second anti-overturning helical pile is driven into the water, and the second connecting crossbeam is connected to the second anti-overturning helical pile. The second steel lever is installed on the second anti-overturning helical pile via the second adaptive fulcrum and the second ball bearing hoop system. The second steel lever is divided into a second long arm and a second short arm of different lengths, centered on the second adaptive fulcrum. One side of the second short arm is rigidly connected to one end of the second steel force-applying beam, and the other end of the second steel force-applying beam is rigidly connected to the second force-bearing plate. The other side of the second long arm is connected to the second servo motor via the second steel force-transmitting beam and the second high-strength steel cable. The first force-bearing plate and the second force-bearing plate are symmetrically welded to the outer wall of the test pile. The monitoring unit includes a first digital force gauge, a second digital force gauge, and a gimbal laser rangefinder. The first digital force gauge is fixed on the first steel force-applying beam and is used to measure the axial force of the first steel force-applying beam. The second digital force gauge is fixed on the second steel force-applying beam and is used to measure the axial force of the second steel force-applying beam. The gimbal laser rangefinder is fixed on the first connecting crossbeam and is used for non-contact monitoring of the deformation and displacement of the test pile.

2. The offshore pile foundation torsional bearing capacity testing device according to claim 1, characterized in that: The first and second load-bearing plates are each welded from two steel plates with an included angle of 30 to 60 degrees. The openings face the outer wall of the test pile and are vertically welded to the outer wall of the test pile. One of the steel plates is perpendicular to the tangent at the welding point. The first and second load-bearing plates are on the same horizontal line, and the line connecting the first and second load-bearing plates and the steel plates perpendicular to the tangent at the welding point passes through the center of the test pile.

3. The offshore pile foundation torsional bearing capacity testing device according to claim 1, characterized in that: Both the first and second anti-overturning helical piles are formed by adding a large-diameter anti-overturning helical blade to the upper part of the helical pile. There are 1 to 3 first and second anti-overturning helical piles. Each of the first anti-overturning helical piles is connected together by a first connecting crossbeam, and each of the second anti-overturning helical piles is connected together by a second connecting crossbeam.

4. The offshore pile foundation torsional bearing capacity testing device according to claim 1, characterized in that: The first ball bearing ring system and the second ball bearing ring system are ring systems composed of balls. The first ball bearing ring system restricts the first steel lever to rotate freely in the loading plane only with the first adaptive fulcrum as the center. The second ball bearing ring system restricts the second steel lever to rotate freely in the loading plane only with the second adaptive fulcrum as the center.

5. The device for testing the torsional bearing capacity of marine pile foundations according to claim 1, characterized in that: The first and second steel levers are made of high-quality alloy steel plates and have an arc-shaped structure with a wider short arm and a narrower long arm.

6. The offshore pile foundation torsional bearing capacity testing device according to claim 1, characterized in that: The first steel force-applying beam, the second steel force-applying beam, the first steel force-transmitting beam, and the first steel force-transmitting beam are made of high-quality alloy steel plates. The steel plates are relatively long and narrow, and are in the shape of long strips.

7. The offshore pile foundation torsional bearing capacity testing device according to claim 1, characterized in that: The first steel force-applying beam and the first steel force-transmitting beam are both at 90° to the first steel lever as a whole; the second steel force-applying beam and the second steel force-transmitting beam are both at 90° to the second steel lever as a whole.

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