A model test device for simulating environmental load and scour effect on suction caisson

Abstract

The application provides a model test device for simulating the environment load and scour effect of a suction bucket, comprising a layered shear box, a plurality of scour pit simulation devices are arranged around the suction bucket in the layered shear box, each scour pit simulation device comprises a support arranged in the layered shear box, a telescopic arm is arranged on each support, the telescopic arm is connected with a cutting surface plate, and the cutting surface plate is arc-shaped and fan-shaped; when each cutting surface plate moves to a position in contact with the outer wall of the suction bucket, the plurality of cutting surface plates are connected with each other to form a ring around the suction bucket, the inner edge of the ring forms a complete circle in contact with the outer wall of the suction bucket, and the outer edge of the ring is higher than the inner edge; at this time, the outer edge is above the saturated soft clay in the water body. The application can simulate the working conditions of the suction bucket foundation under the action of long-term wind and wave load and scour effect, earthquake, and coupling of earthquake and wind and wave load. The application does not arrange a counterweight structure, and the stability and availability of the centrifuge during continuous and uninterrupted rotation are high, so that the test result is accurate.

Description

Technical Field

[0001] This invention relates to the field of offshore wind power foundation structures, specifically a model test device for simulating the environmental loads and scouring effects on a suction bucket. Background Technology

[0002] Chinese patent application (publication number: CN114894509A) discloses a "suction bucket basic test centrifuge test model". This test model has the following problems when used:

[0003] 1. This model cannot simulate the condition of suction bucket foundations under long-term wind and wave loads and scouring effects, as well as the combined effects of earthquakes and wind and wave loads.

[0004] 2. The experimental model uses a counterweight structure, which has poor stability and usability during continuous centrifuge rotation, thus affecting the experimental results;

[0005] 3. This experimental model can only guarantee the verticality of the suction barrel sinking under non-centrifugal conditions. It cannot guarantee it under centrifugal conditions, and therefore cannot conduct experiments under greater centrifugal forces. Summary of the Invention

[0006] Purpose of the invention: To solve the above-mentioned technical problems, the present invention provides a model test device for simulating the environmental load and scouring effect on a suction bucket.

[0007] Technical Solution: This invention provides a model test device for simulating the environmental load and scouring effect of a suction barrel, including a layered shear box. A suction barrel model is set inside the layered shear box. The suction barrel model includes a cylindrical suction barrel connected to a vacuum system. Saturated soft clay is placed at the bottom of the suction barrel, and water is placed at the top of the saturated soft clay. A penetration device is set at the top of the layered shear box, and the suction barrel is connected to the penetration device through a connecting rod.

[0008] The layered shear box is equipped with multiple sets of scour pit simulation devices around the suction barrel. Each scour pit simulation device includes a support set inside the layered shear box, and a telescopic arm is set on each support. The telescopic arm is connected to a cutting panel, which is arc-shaped and fan-shaped. When all the cutting panels move to the position of contacting the outer wall of the suction barrel, the multiple cutting panels are connected to each other to form a ring around the suction barrel. The inner edge of the ring forms a complete circle that fits against the outer wall of the suction barrel, and the outer edge of the ring is higher than its inner edge. At this time, the outer edge of the ring is located above the saturated soft clay.

[0009] Furthermore, the layered shear box is also equipped with a vibration system, which includes a reaction frame connected to the inner wall of the layered shear box. A motor is installed on the reaction frame, and the motor is movably connected to the connecting rod on the suction barrel through a vibration rod.

[0010] Furthermore, an open groove is provided inside the connecting rod, the opening width of which is greater than the width of the excitation rod, and the opening width of the groove is less than the internal width of the groove; a steel ball is provided at the end of the excitation rod, the diameter of which is greater than the opening width of the groove but less than the internal width of the groove, and can move up and down along the inside of the groove.

[0011] Furthermore, the penetration device includes a support located at the top of the layered shear box, a guide rail is provided on the support, a drive rod is provided inside the guide rail, the drive rod passes through the top of the layered shear box and is connected to an electromagnetic adsorption device located inside the layered shear box, a guide cover is connected below the electromagnetic adsorption device, and the top end of the connecting rod is located inside the guide cover; the guide rail is connected to a lateral drive device that enables its lateral displacement, and the top end of the drive rod is connected to a vertical drive device.

[0012] Furthermore, a long strip-shaped groove is provided at the part of the drive rod passing through the layered shear box, and the guide rail extends into the groove and can move within the groove.

[0013] Furthermore, the lateral drive device includes a lateral transmission rack connected to the guide rail, and a gear connected to the bracket and meshing with the lateral transmission rack, the gear being connected to an electric motor.

[0014] Furthermore, a limiting mass block is provided at the top of the connecting rod. The limiting mass block is located inside the guide cover and is restricted by the inner wall of the guide cover, and can move up and down along the inner wall of the guide cover.

[0015] Furthermore, multiple sensors are installed inside the saturated soft clay, with the position after the suction barrel is completely submerged in the soil as a reference. The multiple sensors are distributed in the soil inside and outside the side wall of the suction barrel.

[0016] Furthermore, a T-shaped probe is installed inside the layered shear box.

[0017] Furthermore, multiple laser displacement gauges are installed inside the layered shear box to monitor the displacement of the suction barrel in various directions. Beneficial effects: The model test device for simulating environmental loads and scouring effects on a suction barrel according to the present invention has the following beneficial effects:

[0018] 1. This model can simulate the long-term wind and wave loads and scouring effects on the suction bucket foundation;

[0019] 2. This model can simulate working conditions under the coupled effects of earthquakes and earthquakes and wind and wave loads;

[0020] 3. This model does not have a counterweight structure, ensuring high stability and usability during continuous centrifuge rotation and guaranteeing accurate test results;

[0021] 4. By setting up a penetration device, the displacement deviation during the penetration process can be dynamically corrected, so that the device of the present invention can continuously conduct tests without stopping the centrifuge. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention;

[0023] Figure 2 for Figure 1 Sectional view along axis AA;

[0024] Figure 3 This is a schematic diagram of a partial structure of the penetration device;

[0025] Figure 4 for Figure 3 Sectional view along axis AA;

[0026] Figure 5 This is a structural schematic diagram of the suction bucket model;

[0027] Figure 6 This is a schematic diagram of the cut panel structure. Detailed Implementation

[0028] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0029] like Figures 1-6 As shown, the present invention includes a layered shear box 1, within which a suction barrel model is installed. The suction barrel model includes a suction barrel 2 and a connecting rod 3. A penetration device 4 is installed at the top of the layered shear box 1, and the top end of the connecting rod 3 is movably connected to the penetration device 4. The suction barrel 2 is connected to a vacuum system 30. Saturated soft clay 5 is installed at the bottom of the suction barrel 2, and water 6 is installed at the top of the saturated soft clay 5. Multiple sensors 51, which are earth pressure gauges and / or pore pressure gauges, are installed inside the saturated soft clay 5, with the position after the suction barrel is completely submerged in the soil as a reference. The multiple sensors 51 are distributed in the soil inside and outside the sidewall of the suction barrel. Multiple laser displacement gauges 101 are installed inside the layered shear box 1 to monitor the displacement of the suction barrel in various directions. A T-type penetrometer 53 is also installed inside the saturated soft clay 5.

[0030] Multiple sets of scour pit simulation devices 9 are installed inside the layered shear box 1. Each scour pit simulation device 9 includes a support 91 installed inside the layered shear box, and a telescopic arm 92 is installed on each support 91. One end of the telescopic arm 92 is connected to a cutting panel 93. The cutting panel 93 is arc-shaped and fan-shaped. When all the cutting panels move to the position of contacting the outer wall of the suction barrel 2, the multiple cutting panels are connected to each other to form a ring around the suction barrel. The inner edge of the ring forms a complete circle that fits against the outer wall of the suction barrel, and the outer edge of the ring is higher than its inner edge. At this time, the outer edge is located above the saturated soft clay in the water. To ensure the sealing effect between the cutting panels when they are working, grooves 931 are cut at least at the contact positions between the cutting panel and the suction barrel, and between the cutting panels themselves. Rubber sealing rings are installed in the grooves to ensure that the saturated soft clay in the annular area formed by the multiple cutting panels is isolated from the saturated soft clay in other parts of the water.

[0031] The layered shear box 1 is also equipped with a vibration system 20. The vibration system 20 includes a reaction frame 201 connected to the inner wall of the layered shear box 1. A motor 202 is mounted on the reaction frame 201. The motor 202 is movably connected to the connecting rod 3 on the suction barrel via a vibration rod 203. Specifically, as... Figure 5 As shown, an open groove 311 is provided inside the connecting rod 3. The opening width of the groove 311 is greater than the width of the excitation rod 203 but less than the internal width of the groove 311. A steel ball is provided at the end of the excitation rod 203. The diameter of the steel ball is greater than the opening width of the groove but less than the internal width of the groove, and it can move up and down along the inside of the groove.

[0032] The vacuum system 30 includes a conduit 31 connected at one end to the suction tank 2, and the other end of the conduit 31 connected to a water-gas conversion device 32, which is connected to a vacuum pump 33. Specifically, the vacuum system 30 can be any existing device or system capable of achieving the same function as this invention. The vacuum system 30 also includes components such as a valve body typically used for switching vacuum lines, a vacuum gauge, a pressure relief valve, and a vacuum control valve for controlling the suction force.

[0033] like Figure 3As shown, the penetration device 4 includes a support 41 located at the top of the layered shearing box 1. A guide rail 42 is mounted on the support 41, and a drive rod 43 is disposed within the guide rail 42. The drive rod 43 passes through the top of the layered shearing box 1 and connects to an electromagnetic adsorption device 7 located inside the model box. A guide cover 8 is connected below the electromagnetic adsorption device 7, and the top end of the connecting rod 3 is located inside the guide cover. The guide rail 42 is connected to a lateral drive device capable of lateral displacement, and the top end of the drive rod 43 is connected to a vertical drive device. Specifically, the lateral drive device includes a lateral transmission rack 44 connected to the guide rail 42, and a gear 45 connected to the support 41 and meshing with the lateral transmission rack 44. The gear 45 is connected to the drive device, which can be an electric motor. The vertical drive device connected to the top end of the drive rod 43 is typically a hydraulic drive device, or other existing devices or structures capable of pushing or pulling the drive rod 43. A limiting mass block 301 is provided at the top of the connecting rod 3. The limiting mass block 301 is located inside the guide cover 8 and is restricted by the inner wall of the guide cover 8, and can move up and down along the inner wall of the guide cover 8.

[0034] like Figure 4 As shown, a long strip groove 11 is provided at the part through which the drive rod 43 passes on the layered shear box 1, and the guide rail 42 extends into the groove 11 and can move within the groove 11.

[0035] During testing, the device of this invention is placed on a centrifuge. The centrifuge is started and run to the designed centrifugal acceleration of 50G. Then, a penetration test is conducted using a T-type penetrometer 53 to measure the penetration resistance of the saturated soft clay and estimate the magnitude of the penetration force. The penetration device 4 then operates, causing the suction barrel 2, adsorbed on the electromagnetic adsorption device 7, to descend along the drive rod 43. Once the bottom of the suction barrel 2 reaches the surface of the saturated soft clay, the electromagnetic adsorption device 7 is disconnected, allowing the suction barrel 2 to sink under its own weight first, followed by suction penetration. A vacuum is then created using the vacuum system 30, and the device is activated. Figure 1 As shown, valve #1 is closed, valve #2 is shut off, and the suction force is controlled by the vacuum control valve. The suction force is smoothly transitioned through the water-gas conversion device 32, which also effectively prevents water from being drawn into the vacuum pump 31 until the suction tank 2 sinks to the predetermined position. The guide cover 8 effectively prevents the suction tank 2 from tilting during its descent. A vacuum gauge can be installed on the suction tank 2 to record the vacuum level for easy calculation of the suction force. When horizontal tilting occurs during the suction sinking process, the horizontal drive device can be controlled to rotate the gear clockwise or counterclockwise to move the guide rail horizontally on the support, causing the guide groove to move horizontally. The guide groove acts on the limiting mass block 301 at the top of the suction tank, thereby achieving the effect of horizontal tilt correction for the overall structure.

[0036] After the sinking is completed, the control drive rod 43 moves upward, raising the guide groove above the limiting mass block 301. Then, the scour pit simulation device is controlled, using the rotation of the telescopic arm to adjust the cutting panel to the predetermined scour pit angle, while simultaneously controlling the telescopic arm to extend closer to the suction tank and cut the soil around the suction tank. As a specific embodiment, this invention uses only four cutting panels as an example, such as... Figure 2 As shown, when the front edges of the four cutting panels are in full contact with the suction barrel, the four cutting panels connect to form a ring around the suction barrel. The inner edge of the ring forms a complete circle that fits against the outer wall of the suction barrel, and the outer edge of the ring is higher than its inner edge, and at this time, the outer edge is above the saturated soft clay in the water body. Then, the vacuum system is activated, valve #2 is opened and valve #1 is closed, and the soil inside the annular area formed by the cutting panels is sucked into the water-air conversion device. After the soil in the annular area is cleared, the telescopic arm is controlled to move the cutting panels back to the initial position.

[0037] Then, the excitation system 20 is turned on, and the wind and wave load signal is input to the motor. At this time, the load is transmitted to the connecting rod 3 through the excitation rod 203. The force sensor set on the excitation rod 203 is used to record the output wind and wave load signal to ensure that the input signal and the output signal are consistent. At the same time, the vibration table is turned on to simulate the seismic load. At this time, the system will simulate the offshore wind turbine suction bucket foundation bearing the wind, wave and seismic load, and at the same time consider the scouring effect.

[0038] During the loading process, the acceleration sensor A-1 (e.g.) Figure 1 As shown, the vibration response at the top of the foundation can be obtained by setting it on the suction bucket. The laser displacement meter obtains the vertical and horizontal displacement and rotation angle of the foundation. The soil pressure and pore water pressure are monitored and recorded by the arranged soil pressure gauge and pore pressure gauge along the horizontal and depth directions, respectively.

Claims

1. A model test device for simulating the environmental load and scour effect of a suction bucket, comprising a layered shear box, a suction bucket model is arranged in the layered shear box, the suction bucket model comprises a cylindrical suction bucket, the suction bucket is connected to a vacuum system, a saturated soft clay is arranged at the lower part of the suction bucket, and a water body is arranged at the upper part of the saturated soft clay; a penetration device is arranged at the top of the layered shear box, and the suction bucket is connected to the penetration device through a connecting rod; characterized in that: a plurality of scour pit simulation devices are arranged around the suction bucket in the layered shear box, each scour pit simulation device comprises a support arranged in the layered shear box, an extension arm is arranged on each support, the extension arm is connected to a cutting plane, and the cutting plane is arc-shaped and fan-shaped; when each cutting plane moves to a position in contact with the outer wall of the suction bucket, the plurality of cutting planes are connected to each other to form a ring around the suction bucket, the inner edge of the ring forms a complete circle in contact with the outer wall of the suction bucket, the outer edge of the ring is higher than the inner edge, and at this time, the outer edge of the ring is located above the saturated soft clay. A vibration excitation system is further arranged in the layered shear box, the vibration excitation system comprises a counterforce frame connected to the inner wall of the layered shear box, a motor is arranged on the counterforce frame, and the motor is movably connected to the connecting rod on the suction bucket through a vibration excitation rod.

2. The model test apparatus for simulating the environmental load and scour effect on a suction caisson according to claim 1, wherein: An open sliding groove is arranged in the connecting rod, the opening width of the sliding groove is greater than the width of the vibration excitation rod, and the opening width of the sliding groove is smaller than the internal width of the sliding groove; a steel ball is arranged at the end of the vibration excitation rod, the diameter of the steel ball is greater than the opening width of the sliding groove but smaller than the internal width of the sliding groove, and the steel ball can move up and down along the internal sliding groove.

3. The model test apparatus for simulating the environmental load and scour effect on a suction caisson according to claim 2, characterized in that: The penetration device comprises a support at the top of the layered shear box, a guide rail is arranged on the support, a driving rod is arranged in the guide rail, the driving rod passes through the top of the layered shear box and is connected to an electromagnetic adsorption device arranged in the layered shear box, a guide cover is connected below the electromagnetic adsorption device, and the top end of the connecting rod is located in the guide cover; the guide rail is connected to a transverse driving device capable of transversely moving, and the top end of the driving rod is connected to a vertical driving device.

4. The model test apparatus for simulating the environmental load and scour effect on a suction caisson foundation according to claim 1, wherein: A long strip-shaped sliding groove is arranged at the position through which the driving rod passes on the layered shear box, and the guide rail extends into the sliding groove and can move in the sliding groove.

5. The model test apparatus for simulating the environmental load and scour effect on a suction caisson foundation according to claim 4, wherein: The transverse driving device comprises a transverse transmission rack connected to the guide rail and a gear connected to the support and engaged with the transverse transmission rack, and the gear is connected to a motor.

6. The model test apparatus for simulating the environmental load and scour effect on a suction caisson foundation according to claim 4, wherein: A limiting mass block is arranged at the top end of the connecting rod, the limiting mass block is limited by the inner wall of the guide cover and can move up and down along the inner wall of the guide cover.

7. The model test apparatus for simulating the environmental load and scour effect on a suction caisson foundation according to claim 4, wherein: A plurality of sensors are arranged in the saturated soft clay, and the plurality of sensors are distributed in the soil on the side wall of the suction bucket and outside the side wall.

8. The model test apparatus for simulating the environmental load and scour effect on a suction caisson foundation according to claim 1, wherein: A T-type penetration instrument is arranged in the layered shear box.

9. The model test apparatus for simulating the environmental loads and scour effects on a suction caisson foundation according to claim 1, wherein: A plurality of laser displacement meters are arranged in the layered shear box, and the laser displacement meters are used to monitor the displacement of the suction bucket in each direction.

10. The model test apparatus for simulating the environmental loads and scour effects on a suction caisson foundation according to claim 1, wherein: ​

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