A device and method for excavating a scour pit of a pile foundation in a model box of a geotechnical centrifuge

Abstract

The application discloses a device and method for excavating a scour pit of a pile foundation in a model box of a geotechnical centrifuge, and the device comprises a positioning arm mechanism, a first driving control system and a mechanical arm; the first driving control system is used for driving the mechanical arm; a disc is rotationally connected to a working end of the mechanical arm; an aluminum rod is installed at one end of the disc; a support is arranged at a middle upper section of the aluminum rod, so that the aluminum rod can be axially displaced and the radial displacement of the aluminum rod is limited; a control mechanism comprises a winch motor and a telescopic control arm; a pulley is installed at one end of a pull rod away from the telescopic control arm; a steel wire is wound around the pulley; one end of the steel wire is connected to the winch motor, and the other end of the steel wire is connected to a bottom of the aluminum rod; wherein the winch motor and the telescopic control arm are electrically connected with a second driving control system; one end of the mechanical arm is provided with the centrifuge. The application has the function of excavating any irregular pit, and improves the effect of simulating a scour pit generated by water flow scouring.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pile scouring centrifugal test, in particular to a device and method for excavating a pile scouring pit in a soil centrifuge model box. BACKGROUND

[0002] As the most mainstream foundation type of current marine structures, large-diameter single pile foundation is often subjected to water flow erosion around the seabed, and the larger the pile diameter is, the deeper the scour pit is formed. Unlike the single action of water flow, the pile scour of marine structures needs to consider the wave-flow coupling effect, and the formation mechanism of the scour pit is more complex. The influence of the scour pit on marine structures mainly reflects in the following aspects: changing the natural frequency of the structure, which may cause resonance effect; reducing the lateral bearing capacity of the structure; and reducing the seismic performance of the structure. In order to study the bearing characteristics of the foundation and the dynamic response of the structure under the scour effect, indoor model tests need to be carried out based on a soil centrifuge.

[0003] In the prior art, the scour pit excavation devices for centrifuge tests mainly include: a cutting type scour pit excavation device that directly cuts the soil body by using a cutting tool (such as a ring cutter, a claw cutter, etc.); a vibration type scour pit excavation device that loosens the soil body by using a vibrator to generate high-frequency vibration; an impact type scour pit excavation device that loosens and breaks the soil body by impacting the soil body; and a hydraulic type scour pit excavation device that breaks the soil body by impacting the soil body with high-pressure water flow.

[0004] The scour pit made by using the above excavation devices is too simple or has great randomness and it is difficult to accurately grasp the detail size of the excavated pit. For the actual marine engineering pile scour pit, the geometric size is mostly irregular, and the existing devices cannot well simulate the scour pit generated by water flow scouring.

[0005] Therefore, a device and method for excavating a pile scour pit in a soil centrifuge model box are provided. SUMMARY

[0006] The purpose of the present application is to provide a device and method for excavating a pile scour pit in a soil centrifuge model box, which aims to solve or improve at least one of the above technical problems.

[0007] To achieve the above purpose, the present application provides the following scheme: the present application provides a device for excavating a pile scour pit in a soil centrifuge model box, comprising:

[0008] A positioning arm mechanism comprising a first drive control system and a mechanical arm; the first drive control system is used to drive the mechanical arm;

[0009] A disc rotatably connected to the working end of the mechanical arm;

[0010] An aluminum rod is installed at one end of the disc;

[0011] A support is arranged at the middle and upper section of the aluminum rod, so that the aluminum rod can be displaced along its axial direction, and the radial displacement is limited.

[0012] A control mechanism comprises a winch motor and a telescopic control arm; a pull rod is arranged on the telescopic shaft of the telescopic control arm, a long hole is formed in the pull rod, the aluminum rod is slidably connected along the long hole, and the bottom of the aluminum rod extends out of the pull rod.

[0013] A pulley is arranged at the end of the pull rod away from the telescopic control arm.

[0014] A steel wire is arranged around the pulley; one end of the steel wire is connected with the winch motor, and the other end is connected with the bottom of the aluminum rod.

[0015] The pull rod is arranged below the support; the winch motor and the telescopic control arm are electrically connected with a second drive control system; and one end of the mechanical arm is provided with a centrifuge for driving the disc to rotate.

[0016] According to the pile scouring pit excavation device in the geotechnical centrifuge model box provided by the application, the aluminum rod comprises an upper aluminum rod and a lower aluminum rod; the upper aluminum rod is detachably connected at the center of the bottom surface of the disc through a first bolt; the lower aluminum rod is detachably connected at the bottom of the upper aluminum rod through a second bolt; the length of the upper aluminum rod is less than the length of the lower aluminum rod; the lower aluminum rod penetrates through the long hole, and the upper aluminum rod and the lower aluminum rod are slidably connected with the support.

[0017] According to the pile scouring pit excavation device in the geotechnical centrifuge model box provided by the application, the first drive control system comprises a driving piece and a first computer; the driving piece is used for driving the mechanical arm, and the first computer is electrically connected with the driving piece.

[0018] According to the pile scouring pit excavation device in the geotechnical centrifuge model box provided by the application, the second drive control system comprises a second computer, and the winch motor and the telescopic control arm are electrically connected with the second computer.

[0019] According to the pile scouring pit excavation device in the geotechnical centrifuge model box provided by the application, the bottom of the lower aluminum rod is provided with a pointed end.

[0020] According to the pile scouring pit excavation device in the geotechnical centrifuge model box provided by the application, a vertical hole is formed through the support, and the upper aluminum rod and the lower aluminum rod are slidably connected along the vertical hole.

[0021] The application further provides a pile scouring pit excavation method in a geotechnical centrifuge model box, which comprises the following steps:

[0022] Step 1, Device Positioning: The working end of the robotic arm is moved to the location of the excavation scour pit by controlling the first drive control system. After verifying the position, the centrifuge is connected to the disc.

[0023] Step 2: Determine the excavation depth and irregular shape: Confirm the parameters for the excavation depth and the shape of the scour pit; for irregularly shaped scour pits, divide the outer curve of the scour pit into several segments, obtain the function curve of each segment, and record the function.

[0024] Step 3: Equipment debugging: Replace the aluminum rod with one of the corresponding length to adjust the excavation depth; the second drive control system adjusts the output power of the winch motor and telescopic control arm based on the function curve obtained in step 2 to excavate irregular scour pits.

[0025] Step 4: Excavating the scour pit: The centrifuge drives the disc and aluminum rod to rotate, and the second drive control system adjusts the winch motor and telescopic control arm in real time, so that the steel wire cuts the sand or soil to form the scour pit.

[0026] Step 5: Remove the excavated soil: Remove the soil scraped off by the wire during the excavation of the scouring pit.

[0027] According to the construction method of the excavation device for pile foundation scour pit inside the model box of the geotechnical centrifuge provided by the present invention, in step four, the length of the steel wire is adjusted by the winch motor and the pulley, and the steel wire is kept taut by the winch motor.

[0028] According to the construction method of the excavation device for pile foundation scour pit inside the model box of the geotechnical centrifuge provided by the present invention, in step two, the outer curve of the scour pit is divided into 360 segments, and each segment has the same length.

[0029] The present invention discloses the following technical effects:

[0030] This invention allows for adjustment of the excavation depth by replacing aluminum rods of corresponding lengths. The second drive control system adjusts the winch motor and telescopic control arm in real time, enabling the steel wire to cut sand or soil to form scour pits. It has the function of excavating any irregular pits, and the size of the excavated pits is accurate and controllable, improving the effect of simulating scour pits generated by water flow.

[0031] The first drive control system of the present invention drives the robotic arm to move the disc and aluminum rod to the location of the excavation scour pit, which can meet the positioning of pile foundations of different sizes and shapes; improves the accuracy and stability of the scour pit model, and makes the device more developable and scalable. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the present invention;

[0034] Figure 2 This is a schematic diagram of the tie rod structure in this invention;

[0035] Figure 3 A schematic diagram of the structure of a regular scour pit;

[0036] Figure 4 A schematic diagram of the structure of an irregular scour pit;

[0037] Figure 5 This is a schematic diagram of the operation of the pull rod and the winch motor in this invention;

[0038] Figure 6 This is a process flow diagram of the construction method of the present invention;

[0039] Among them, 1. robotic arm; 2. disc; 3. aluminum rod; 4. bracket; 5. winch motor; 6. telescopic control arm; 7. pull rod; 8. long through hole; 9. pulley; 10. steel wire; 11. drive component; 12. first computer; 13. second computer; 14. tip. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Reference Figures 1-6 This invention provides a device for excavating pile foundation scour pits inside a geotechnical centrifuge model box, comprising:

[0043] The positioning arm mechanism includes a first drive control system and a robotic arm 1; the first drive control system is used to drive the robotic arm 1.

[0044] The disc 2 is rotatably connected to the working end of the robotic arm 1; the robotic arm 1 drives the disc 2 to adjust its position and drives the disc 2 and aluminum rod 3 to move up and down.

[0045] Aluminum rod 3, one end of which is mounted on disc 2;

[0046] The bracket 4 is located in the upper middle section of the aluminum rod 3 so that the aluminum rod 3 can move along its axial direction while its radial displacement is restricted.

[0047] The control mechanism includes a winch motor 5 and a telescopic control arm 6; a pull rod 7 is installed on the telescopic shaft of the telescopic control arm 6, and an elongated through hole 8 is opened on the pull rod 7. An aluminum rod 3 is slidably connected along the elongated through hole 8, and the bottom of the aluminum rod 3 extends out of the pull rod 7.

[0048] Pulley 9 is installed at the end of pull rod 7 away from telescopic control arm 6;

[0049] A steel wire 10 is wound around a pulley 9; one end of the steel wire 10 is connected to a winch motor 5, and the other end is connected to the bottom of an aluminum rod 3.

[0050] Among them, the pull rod 7 is located below the bracket 4; the hoist motor 5 and the telescopic control arm 6 are electrically connected to the second drive control system; a centrifuge (not shown in the figure) is installed at one end of the robotic arm 1, and the centrifuge is used to drive the disc 2 to rotate; the aluminum rod 3 is slidably connected along the long through hole 8, and the pull rod 7 rotates synchronously with the aluminum rod 3 under the drive of the centrifuge, thereby driving the steel wire 10 to rotate, so as to realize the excavation operation of the scour pit;

[0051] With this configuration, the present invention can adjust the excavation depth by replacing the aluminum rod 3 of the corresponding length. The second drive control system can adjust the winch motor 5 and the telescopic control arm 6 in real time, so that the steel wire 10 cuts the sand or soil to form a scour pit. It has the function of excavating any irregular pit. The size of the excavated pit is accurate and controllable, which improves the effect of simulating the scour pit generated by the outflow of water.

[0052] The first drive control system of the present invention drives the robotic arm 1, which moves the disc 2 and the aluminum rod 3 to the location of the excavation scour pit, thus satisfying the positioning of pile foundations of different sizes and shapes; improving the accuracy and stability of the scour pit model, and making the device more developable and scalable.

[0053] Further optimization of the scheme: aluminum rod 3 includes an upper aluminum rod and a lower aluminum rod; the upper aluminum rod is detachably connected to the center of the bottom surface of the disc 2 by a first bolt; the lower aluminum rod is detachably connected to the bottom of the upper aluminum rod by a second bolt; the length of the upper aluminum rod is less than the length of the lower aluminum rod, the lower aluminum rod passes through the elongated through hole 8, and both the upper and lower aluminum rods are slidably connected to the bracket 4.

[0054] Further optimization of the scheme: the first drive control system includes a drive component 11 and a first computer 12; the drive component 11 is used to drive the robotic arm 1, and the first computer 12 is electrically connected to the drive component 11; the drive component 11 is a dedicated driver for the robotic arm; the internal structure and working principle of the robotic arm 1 and the drive component 11 are existing technologies and will not be described in detail here; the first computer 12 can accurately locate the excavated scour pit, and after confirming the excavation position, the robotic arm 1 can be fixed to the upper wall of the centrifuge, and the centrifuge drives the disc 2 to rotate.

[0055] The scheme is further optimized. The second drive control system includes a second computer 13, and the hoisting motor 5 and the telescopic control arm 6 are all electrically connected to the second computer 13.

[0056] The telescopic control arm 6 is used to drive the pull rod 7 to move horizontally. The type and model of the telescopic control arm 6 can be set according to the specific environment. For example, it can be a cylinder, hydraulic cylinder, electric actuator, etc., but no specific limitation is made in this embodiment.

[0057] The design was further optimized by setting the bottom of the lower aluminum rod as a pointed tip 14, which makes it easier to insert into sand or soil.

[0058] To further optimize the design, a vertical through hole is provided on the bracket 4, and the upper and lower aluminum rods are slidably connected along the vertical through hole, so that the aluminum rod 3 moves vertically as a whole.

[0059] This invention also provides a method for excavating a pile foundation scour pit inside a geotextile centrifuge model box, comprising the following steps:

[0060] Step 1, Device Positioning: The working end of the robotic arm 1 is moved to the location of the excavation scour pit by controlling the first drive control system. After verifying the position, the centrifuge is connected to the disc 2.

[0061] Step 2: Determine the excavation depth and irregular shape: Confirm the parameters for the excavation depth and the shape of the scour pit; for irregularly shaped scour pits, divide the outer curve of the scour pit into several segments, obtain the function curve of each segment, and record the function.

[0062] Step 3, Equipment Debugging: Replace the aluminum rod 3 with one of the corresponding length to adjust the excavation depth; the second drive control system adjusts the output power of the winch motor 5 and the telescopic control arm 6 based on the function curve of each segment obtained in Step 2 to excavate irregular scour pits.

[0063] Step 4: Excavating the scour pit: The centrifuge drives the disc 2 and aluminum rod 3 to rotate, and the second drive control system adjusts the winch motor 5 and telescopic control arm 6 in real time, so that the steel wire 10 cuts the sand or soil to form the scour pit.

[0064] Step 5: Remove excavated soil: Remove the soil scraped off by the steel wire 10 during the excavation of the scouring pit.

[0065] To further optimize the scheme, in step four, the length of the steel wire 10 is adjusted by the winch motor 5 and the pulley 9, and the steel wire 10 is kept taut by the winch motor 5. With this setting, by adjusting the length of the steel wire 10 and the angle between the steel wire 10 and the aluminum rod 3, the purpose of creating an irregularly shaped excavation pit can be achieved.

[0066] To further optimize the scheme, in step two, the outer curve of the scour pit is divided into 360 segments, and each segment has the same length.

[0067] The working principle of excavating irregular scour pits:

[0068] Reference Figure 3 For a regular scour pit, r is the radius of the outer edge of the scour pit, θ is the distance from any point on the outer edge to the location of the pile, and r(θ) is a constant value.

[0069] For irregular scour pits to form, then r must be a function of θ, i.e., r = f(θ). (See reference...) Figure 4 If it is necessary to dig a scour pit with an outer edge shape of curve m, (where point o is the location of the pile, θ is adjusted by the upper rotating disk 2 and aluminum rod 3, θ = wt, w is the rotation speed).

[0070] By breaking down this curve, if there is a certain pattern, it can be divided into several segments, and the function curve of each segment can be obtained by fitting or mathematical calculation. If the curve has no pattern, then the idea of ​​differentiation is used, for example, θ∈[0,2π]. In this embodiment, the curve is divided into 360 equal parts, and the function curve of each segment is obtained by fitting each small segment. The computer is then programmed, and the second computer 13 adjusts the winch motor 5 and the telescopic control arm 6 in real time, so that the steel wire 10 cuts the sand or soil to form a scour pit, thus completing the excavation of the scour pit.

[0071] The telescopic control arm 6 can push and pull the rod 7 left and right. The length of the steel wire 10 can be adjusted by the pulley 9. The end of the steel wire 10 is connected to the winch motor 5. The winch motor 5 keeps the steel wire 10 in a taut state, which is convenient for excavating sand or soil.

[0072] Reference Figure 5 By adjusting the winch motor 5 and the telescopic control arm 6 through the second computer 13, the radius of the flushing pit is changed from r to r', and l (the length of the steel wire 10) is changed to l'. (The angle between the pile and the steel wire 10) has changed to The radius was continuously adjusted to achieve the goal of digging irregular pits.

[0073] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0074] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A device for excavating pile foundation scour pits inside a geotextile centrifuge model box, characterized in that, include: The positioning arm mechanism includes a first drive control system and a robotic arm (1); the first drive control system is used to drive; the robotic arm (1); a disk (2) rotatably connected to the working end of the robotic arm (1); an aluminum rod (3) with one end mounted on the disk (2); and a bracket (4) located in the upper middle section of the aluminum rod (3) so that the aluminum rod (3) can move along its axial direction and its radial displacement is restricted. The control mechanism includes a winch motor (5) and a telescopic control arm (6); a pull rod (7) is installed on the telescopic shaft of the telescopic control arm (6), and an elongated through hole (8) is opened on the pull rod (7). The aluminum rod (3) is slidably connected along the elongated through hole (8), and the bottom of the aluminum rod (3) extends out of the pull rod (7); a pulley (9) is installed at the end of the pull rod (7) away from the telescopic control arm (6); A steel wire (10) is wound around the pulley (9); one end of the steel wire (10) is connected to the hoist motor (5), and the other end is connected to the bottom of the aluminum rod (3); The pull rod (7) is located below the bracket (4); the hoist motor (5) and the telescopic control arm (6) are electrically connected to the second drive control system; a centrifuge is installed at one end of the robotic arm (1), and the centrifuge is used to drive the disc (2) to rotate. The aluminum rod (3) includes an upper aluminum rod and a lower aluminum rod; the upper aluminum rod is detachably connected to the center of the bottom surface of the disc (2) by a first bolt; the lower aluminum rod is detachably connected to the bottom of the upper aluminum rod by a second bolt; the length of the upper aluminum rod is less than the length of the lower aluminum rod, the lower aluminum rod passes through the elongated through hole (8), and both the upper aluminum rod and the lower aluminum rod are slidably connected to the bracket (4); The first drive control system includes a drive unit (11) and a first computer (12); the drive unit (11) is used to drive the robotic arm (1), and the first computer (12) is electrically connected to the drive unit (11); The second drive control system includes a second computer (13), the hoist motor (5) and the telescopic control arm (6) are electrically connected to the second computer (13); the bottom of the lower aluminum rod is set as a pointed tip (14); a vertical through hole is provided on the bracket (4), and the upper aluminum rod and the lower aluminum rod are slidably connected along the vertical through hole.

2. A method for excavating scour pits in a geotextile centrifuge model box, based on the excavation device for scour pits in a geotextile centrifuge model box as described in claim 1, characterized in that... Includes the following steps: Step 1, Device positioning: Control the working end of the robotic arm (1) to move to the location of the excavation scour pit through the first drive control system, and connect the centrifuge to the disc (2) after verifying the position; Step 2: Determine the excavation depth and irregular shape: Confirm the parameters for the excavation depth and the shape of the scour pit; for irregularly shaped scour pits, divide the outer curve of the scour pit into several segments, obtain the function curve of each segment, and record the function. Step 3, Equipment Adjustment: Replace the aluminum rod (3) with one of the corresponding length to adjust the excavation depth; the second drive control system adjusts the output power of the winch motor (5) and the telescopic control arm (6) based on the function curves obtained in Step 2 for each segment. To enable the excavation of irregular scour pits; Step 4: Excavating the scour pit: The centrifuge drives the disc (2) and aluminum rod (3) to rotate. The second drive control system adjusts the winch motor (5) and telescopic control arm (6) in real time so that the steel wire (10) cuts the sand or soil to form a scour pit. Step 5: Remove the excavated soil: Remove the soil scraped off by the steel wire (10) when excavating the scouring pit.

3. The method for excavating the pile foundation scour pit inside the geotextile centrifuge model box according to claim 2, characterized in that: In step four, the length of the steel wire (10) is adjusted by the winch motor (5) and pulley (9), and the steel wire (10) is kept taut by the winch motor (5).

4. The method for excavating the pile foundation scour pit inside the geotextile centrifuge model box according to claim 3, characterized in that: In step two, the outer curve of the scour pit is divided into 360 segments, and each segment has the same length.

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