A collapsible loess area foundation ramming depth control device and ramming method

Abstract

The present application relates to the technical field of foundation treatment, and especially relates to a device for controlling ramming depth of foundation in collapsible loess area and a ramming method. The device comprises a device shell, a depth control mechanism and a ramming mechanism. The device shell comprises a top plate and two side plates. The two side plates are located at the lower part of the two sides of the top plate, and have a containing cavity between the two side plates. The depth control mechanism comprises a lifting module and a lifting frame. The lifting module is installed on the top plate of the device shell. The lifting frame is installed at the bottom end of the lifting module and located in the containing cavity. The ramming mechanism comprises a line laying module and a ramming hammer. The line laying module is installed in the lifting frame. The ramming hammer is connected to the bottom of the line laying module. The device can precisely adjust the ramming depth.

Description

Technical Field

[0001] This invention relates to the field of foundation treatment technology, and in particular to a device and method for controlling the compaction depth of foundations in collapsible loess areas. Background Technology

[0002] The foundation refers to the soil or rock mass that supports the foundation of a building. Soil layers that serve as building foundations are divided into rock, gravelly soil, sandy soil, silty soil, clayey soil, and artificial fill. There are two types of foundations: natural foundations and artificial foundations. Natural foundations are natural soil layers that do not require reinforcement, while artificial foundations require reinforcement treatment. Common methods include stone chip cushion layers, sand cushion layers, and backfilling with mixed lime and soil and then compacting. Before construction, the foundation must be compacted to ensure the stability of the building.

[0003] In foundation treatment engineering, dynamic compaction is often used for special geological conditions such as collapsible loess to improve the bearing capacity of the foundation and eliminate collapsibility. Dynamic compaction primarily utilizes the impact energy generated by a heavy hammer falling freely from a height to compact the soil. Traditional equipment for this process typically includes a mobile chassis, support frame, lifting mechanism, and hammer. The lifting mechanism often employs a winch system, where a motor drives a drum to wind and unwind a steel wire rope, thereby lifting or releasing the connected hammer.

[0004] The lifting height of the tamping hammer can be directly controlled by a winch, but the length of the winch's winding and unwinding rope is difficult to measure accurately, and due to the influence of mechanical inertia, the actual falling depth of the tamping hammer is prone to deviate from the design depth, which cannot meet the requirements of high-precision foundation treatment. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a foundation compaction depth control device and compaction method in collapsible loess areas, so as to achieve precise adjustment of compaction depth.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] A foundation compaction depth control device for collapsible loess areas includes: a device shell, a depth control mechanism, and a compaction mechanism; the device shell includes a top plate and two side plates, the side plates being located at the lower parts on both sides of the top plate, and a receiving cavity between the side plates; the depth control mechanism includes a lifting module and a lifting frame, the lifting module being installed on the top plate of the device shell, and the lifting frame being installed at the bottom end of the lifting module and located within the receiving cavity; the compaction mechanism includes a line-laying module and a compaction hammer, the line-laying module being installed in the lifting frame, and the compaction hammer being connected to the bottom of the line-laying module.

[0008] Optionally, the lifting module includes a fixed frame, a lifting rod, a first motor, and a ball screw nut assembly. The top plate has a slot starting from the middle, the fixed frame is fixedly installed in the slot, the first motor is installed on the top of the fixed frame, the lifting rod is connected to the first motor through the ball screw nut assembly, and the lifting frame is installed at the bottom of the lifting rod.

[0009] Optionally, the fixed frame includes two parallel fixed plates, which are mounted on the top plate via L-shaped mounting plates, and the lower end of the lifting rod is connected to the lifting frame via an L-shaped mounting plate.

[0010] Optionally, the ball screw nut assembly includes a ball screw and a ball sleeve. The top end of the ball screw is connected to the output shaft of the first motor, and the bottom end is rotatably mounted on a fixed frame. The ball sleeve is mounted on the ball screw, and the lifting rod is fixedly mounted on the ball sleeve.

[0011] Optionally, the wire feeding module includes a second motor, a take-up and feed wheel, and a steel wire. The second motor is mounted on the lifting frame, the take-up and feed wheel is mounted on the output shaft of the second motor, the steel wire is wound on the take-up and feed wheel, and the bottom of the lifting frame has a hole for the steel wire to pass through. The lower end of the steel wire is connected to a tamping hammer.

[0012] Optionally, a guide mechanism is provided between both sides of the tamping hammer and the inner sides of the two side plates.

[0013] Optionally, the outer casing of the device is U-shaped, and tracks are provided at the bottom of both side plates.

[0014] Optionally, a laser rangefinder sensor is provided on the inner side of the side plate of the device housing, and the laser rangefinder sensor is used to detect the settlement of the ground corresponding to the tamping hammer.

[0015] Optionally, a power supply and control panel are provided on a side panel of one side of the device housing.

[0016] This invention also provides a compaction method for a foundation compaction depth control device in collapsible loess areas, comprising the following steps: The depth control mechanism lowers and locks the lifting frame via the lifting module; The line-laying module lays out the line, and the tamping hammer falls vertically under the action of gravity to compact the ground. The line-laying module then retracts the line and lifts the tamping hammer to the set height, repeating the lifting and falling process. During continuous compaction, the ground distance at the compaction point is monitored in real time, the ground settlement is calculated, and when the settlement reaches the set threshold, the lifting frame is adjusted accordingly to keep the effective drop distance of the compaction hammer within the preset range. After the compaction work at a single point is completed, move to the next compaction point and repeat the above process until the entire construction area is completed.

[0017] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: The device of this invention consists of three main parts: a housing, a depth control mechanism, and a compaction mechanism. The housing provides overall support and housing space. The lifting module of the depth control mechanism is mounted on the top plate, responsible for providing precise vertical drive. The lifting frame at the bottom is located within the housing cavity, forming the execution terminal for depth adjustment. The compaction mechanism is integrated on the lifting frame and controls the raising and lowering of the compaction hammer through a wire-laying module to complete the compaction action. The depth control mechanism allows for independent and precise setting of the reference height of the lifting frame in the vertical direction, which directly determines the starting point of the free fall of the compaction hammer, thereby achieving pre-control of the compaction depth. Compared to the coarse control method that relies on the length of the winch's rope and cannot be precisely calibrated, this solution fundamentally constructs a basic architecture for high-precision depth control by structurally decoupling the depth preset function from the compaction execution function and establishing a clear hierarchical control relationship, thus achieving precise adjustment of the compaction depth.

[0018] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0020] Figure 1 This is a schematic diagram of the overall compaction device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the lifting frame and cable-laying module provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the lifting module provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a ball screw nut assembly provided in an embodiment of the present invention; In the diagram: 1. Device housing; 2. Track; 3. Power supply; 4. Control panel; 5. Fixing frame; 6. First motor; 7. Ball screw; 8. Ball sleeve; 9. Lifting rod; 10. Mounting plate; 11. Lifting frame; 12. Second motor; 13. Retracting wheel; 14. Steel wire; 15. Tamping hammer; 16. Limiting rod. Detailed Implementation

[0021] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms include and / or encompass are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] Example 1 like Figure 1 As shown in the figure, this embodiment proposes a foundation compaction depth control device for collapsible loess areas, including: a device shell 1, a depth control mechanism, and a compaction mechanism; the device shell 1 includes a top plate and two side plates, the side plates are located at the lower part of the top plate on both sides, and there is a receiving cavity between the side plates; the depth control mechanism includes a lifting module and a lifting frame 11, the lifting module is installed on the top plate of the device shell 1, and the lifting frame 11 is installed at the bottom of the lifting module and located in the receiving cavity; the compaction mechanism includes a line-laying module and a compaction hammer 15, the line-laying module is installed in the lifting frame 11, and the compaction hammer 15 is connected to the bottom of the line-laying module.

[0023] The top plate and side plates of the outer casing 1 form an integral support structure. The side plates are located on the lower sides of the top plate, and the cavity between them provides installation space and a protective environment for the depth control mechanism and the compaction mechanism. The lifting module of the depth control mechanism is installed on the top plate and can drive the lifting frame 11 to move vertically, thereby adjusting the height of the compaction mechanism. The wire-laying module of the compaction mechanism is installed inside the lifting frame 11, and the compaction hammer 15 connected to its bottom can complete the lifting and compaction actions under the action of the wire-laying module.

[0024] This device changes the traditional extensive control method through the coordinated operation of the depth control mechanism and the compaction mechanism. The depth control mechanism can accurately adjust the height of the compaction mechanism, and the compaction mechanism can stably complete the compaction operation. The two together with the outer shell 1 of the device form an organic whole, which meets the needs of high-precision foundation treatment in collapsible loess areas.

[0025] like Figure 3 , Figure 4As shown, the lifting module includes a fixed frame 5, a lifting rod 9, a first motor 6, and a ball screw nut assembly. The top plate has a slot starting from the middle, and the fixed frame 5 is fixedly installed in the slot. The first motor 6 is installed on the top of the fixed frame 5. The lifting rod 9 is connected to the first motor 6 through the ball screw nut assembly, and the lifting frame 11 is installed at the bottom of the lifting rod 9.

[0026] The lifting module adopts a transmission system in which the first motor 6 drives the ball screw and nut pair, which in turn drives the lifting rod 9 to move linearly. The fixed frame 5 is fixed to the top plate slot, providing a stable installation base for the entire lifting module. The first motor 6 serves as the power source, and its rotational motion is converted into the lifting motion of the lifting frame 11 through the ball screw and nut pair.

[0027] Conventional technologies use limit switches and encoders to control lifting, but encoders can only provide position feedback without the ability to adjust. Moreover, the loess soil is prone to vibration, and limit switches are easily triggered by impacts. In contrast, the mechanical rigidity of the ball screw and nut pair can resist construction vibrations and avoid frequent failures. When the tracked device moves in soft soil, the stable transmission of the ball screw and nut pair can ensure that the compaction depth does not deviate with slight equipment displacement. This is something that the combination of limit switches and encoders cannot achieve.

[0028] The fixed frame 5 includes two parallel fixed plates, which are mounted on the top plate via an L-shaped mounting plate 10. The lower end of the lifting rod 9 is connected to the lifting frame 11 via the L-shaped mounting plate 10.

[0029] The right-angle structure of the L-shaped mounting plate 10 can distribute the force between components to two mutually perpendicular directions, resulting in more uniform force distribution. Compared with simple planar connections or welding, it has stronger impact resistance and can withstand the problem of the tamping hammer 15 falling off, thus extending the service life of the equipment. From the perspective of disassembly and maintenance, the detachable design of the bolts makes it easy to disassemble the connections between components. When the equipment needs to be transported, repaired, or components replaced, disassembly and assembly operations can be completed quickly, reducing maintenance difficulty and costs and improving the flexibility of equipment use.

[0030] The ball screw nut assembly includes a ball screw 7 and a ball sleeve 8. The top end of the ball screw 7 is connected to the output shaft of the first motor 6, and the bottom end is rotatably mounted on the fixed frame 5. The ball sleeve 8 is mounted on the ball screw 7, and the lifting rod 9 is fixedly mounted on the ball sleeve 8.

[0031] The ball sleeve 8 contains circulating balls that engage with the helical groove of the ball screw 7, converting the rotational motion of the screw into linear movement of the sleeve itself. The lifting rod 9 is fixedly mounted on the ball sleeve 8 and thus rises and falls together with it.

[0032] In another embodiment, limiting sliders can be fixedly connected to both the front and rear ends of the ball screw sleeve 8. The limiting sliders at both ends of the ball screw sleeve 8 cooperate with the inner wall of the fixed frame 5 to restrict the rotational freedom of the sleeve, so that it can only make linear motion in the vertical direction along the screw. The grooves on the left and right sides of the fixed frame 5 provide motion trajectory constraints for the lifting rod 9, preventing the lifting rod 9 from swaying laterally during the lifting process. This multi-limiting and transmission design allows the lifting height of the lifting rod 9, which drives the lifting frame 11 and the tamping hammer 15, to be precisely controlled by the rotation angle of the first motor 6.

[0033] In this embodiment, the first motor 6 is a 1.5-3kW servo motor, such as the Panasonic MSMD032G1U (3kW, rated speed 3000rpm, rated torque 9.55N·m). This type of motor is small in size and has high control precision. When paired with a 1:10-1:20 reduction gearbox (because the speed of the ball screw 7 needs to be matched with the lifting speed, the reduction gearbox can reduce the output speed of the motor and increase the torque), it can meet the requirements of smooth lifting and precise positioning of the lifting assembly.

[0034] like Figure 1 , Figure 2 As shown, the wire feeding module includes a second motor 12, a take-up and feed wheel 13, and a steel wire 14. The second motor 12 is installed in the lifting frame 11, the take-up and feed wheel 13 is installed on the output shaft of the second motor 12, and the steel wire 14 is wound on the take-up and feed wheel 13. The bottom of the lifting frame 11 has a hole for the steel wire 14 to pass through, and the lower end of the steel wire 14 is connected to a tamping hammer 15.

[0035] The second motor 12 provides power, driving the take-up and release wheel 13 to rotate in both directions, thus retracting and extending the steel wire 14. The steel wire 14 passes through a hole at the bottom of the lifting frame 11 and connects to the tamping hammer 15. When the tamping hammer needs to fall, the second motor 12 controls the take-up and release wheel 13 to release the steel wire 14, allowing the tamping hammer to fall freely under gravity. After tamping is completed, the second motor 12 reverses to retract the steel wire 14, raising the tamping hammer to a predetermined height. During this process, the function of the wire release module is to perform the release-lifting cycle of the tamping hammer, while the starting height of the tamping hammer's fall is independently set by the depth control mechanism by adjusting the height of the lifting frame 11. This functional separation design simplifies the control logic and improves the modularity and reliability of the system.

[0036] In this embodiment, the second motor 12 is a 3-5.5kW braking type three-phase asynchronous motor, such as YEJ2-132S-4 (5.5kW, rated speed 1440rpm, rated torque 36.8N·m). This motor is equipped with an electromagnetic braking device, which has a rapid braking response and can brake and lock immediately after the tamping hammer 15 is raised to the specified height to prevent the tamping hammer 15 from falling due to the slippage of the steel wire 14. At the same time, its starting torque is large (the stall torque can reach 2.2 times the rated torque), which can smoothly drive the tamping hammer 15 to be raised.

[0037] Furthermore, a guide mechanism can be provided between the two sides of the tamping hammer 15 and the inner side of the two side plates. The guide mechanism can adopt existing technology to constrain the vertical trajectory of the tamping hammer 15 during the lifting and lowering process.

[0038] In this embodiment, the guiding mechanism can be specifically defined as follows: both the left and right ends of the tamping hammer 15 are fixedly connected to limit rods 16, and a T-shaped locking block is fixedly connected to the side of the limit rod 16 near the device housing 1. The device housing 1 has a sliding groove that cooperates with the T-shaped locking block. The cooperation between the limit rods 16 and the T-shaped locking block at both ends of the tamping hammer 15 and the sliding groove of the device housing 1 forms a reliable tamping hammer guiding mechanism. During the lifting and falling of the tamping hammer 15, the T-shaped locking block slides along the sliding groove of the housing, which strictly constrains the movement trajectory of the tamping hammer 15 and effectively prevents the tamping hammer 15 from shifting laterally due to wind, mechanical vibration or uneven ground. This guiding structure not only ensures that the tamping hammer 15 always acts on the designated tamping point, improves the uniformity of the tamping operation, and avoids substandard local foundation treatment, but also reduces the collision damage of the tamping hammer 15 to other parts of the device, reduces the risk of equipment failure, and improves the safety during construction, avoiding safety accidents caused by the tamping hammer 15 shifting.

[0039] The outer casing 1 of the device is U-shaped, and tracks 2 are provided at the bottom of both side plates.

[0040] The U-shaped housing 1 allows the device to stand upright above the impact point. The track 2 distributes the weight of the equipment over a larger contact surface through a continuous ground contact area, thereby significantly reducing the ground pressure and preventing the equipment from getting stuck in mud or slipping when moving or parking.

[0041] A laser rangefinder is provided on the inner side of the side plate of the device housing 1. The laser rangefinder is used to detect the settlement of the ground corresponding to the tamping hammer 15.

[0042] The laser rangefinder sensor is installed inside the side plate of the device housing 1, with the laser emission and reception directions facing the ground. When the same location is continuously compacted, the ground gradually subsides as the soil is compacted. The distance data acquired by the laser rangefinder sensor in real time will change. By calculating the difference between the data before and after, the ground settlement can be accurately obtained, achieving adaptive compensation control.

[0043] A power supply 3 and a control panel 4 are installed on one side panel of the device housing 1. The power supply 3 provides power to the first motor 6, the second motor 12, the laser rangefinder sensor, and the control system of the entire device. The control panel 4 serves as a human-machine interface, integrating parameter input, command transmission, and status display functions.

[0044] In summary, this device achieves precise adjustment of compaction depth through a precision transmission mechanism consisting of a first motor 6, a ball screw 7, and a ball sleeve 8. When the first motor 6 drives the ball screw 7 to rotate, the ball sleeve 8, under the constraint of the limiting slider and the groove, makes a stable linear lifting motion along the ball screw 7, thereby driving the lifting rod 9 and the lifting frame 11 to lift synchronously. Compared with the coarse control of traditional winches, the ball screw 7 transmission has the characteristics of high transmission efficiency, high positioning accuracy, and small return gap. The rotation angle of the first motor 6 can be precisely set through the control panel 4, thereby precisely controlling the lifting height of the lifting rod 9, and ultimately achieving precise control of the working depth of the compaction hammer 15. This meets the differentiated requirements of different projects for the compaction depth of the foundation and effectively improves the quality of foundation treatment.

[0045] The lower part of the outer shell 1 of the device adopts a tracked mobile mechanism 2. Compared with the traditional wheeled mobile structure, the track 2 has a larger contact area with the ground and a smaller ground pressure. In soft ground such as collapsible loess, the track 2 can effectively distribute the weight of the equipment and prevent the equipment from sinking into the soil. At the same time, the anti-slip texture on the surface of the track 2 can enhance the friction with the ground and prevent slipping. This allows the device to move flexibly on construction sites with complex terrain and quickly position itself between different construction areas, significantly improving construction efficiency and reducing the initial investment cost of site leveling.

[0046] Example 2 This embodiment provides a compaction method for a foundation compaction depth control device in collapsible loess areas, including the following steps: The depth control mechanism drives the lifting frame 11 to descend and lock through the lifting module, setting the initial reference height for the tamping.

[0047] The line-laying module lays out the line, and the tamping hammer 15 falls vertically under the action of gravity to compact the ground. The line-laying module then retracts the line and lifts the tamping hammer 15 to the set height, repeating the lifting and falling process. As the collapsible loess beneath the tamping hammer 15 is continuously compacted during repeated tamping at the same point, the corresponding ground gradually subsides. This settlement causes the actual falling distance of the tamping hammer 15 to exceed the preset value, resulting in an increase in tamping energy, affecting the uniformity of compaction, and potentially damaging the equipment.

[0048] During continuous compaction, the ground distance at the compaction point is monitored in real time, and the ground settlement is calculated. When the settlement reaches a set threshold, the lifting frame 11 is adjusted downwards accordingly to ensure that the effective drop distance of the compaction hammer 15 remains within a preset range each time. This real-time calculation of ground settlement is not handled only after completion; rather, it automatically triggers the depth control mechanism when the settlement reaches a certain intermediate threshold, synchronously lowering the lifting frame 11 along with the entire compaction mechanism. This offsets the increased actual drop distance of the hammer due to ground settlement by lowering the starting point, ensuring that the effective drop distance of the hammer from release to contact with the ground remains within the preset range each time. This guarantees constant compaction energy and uniform, controllable construction quality.

[0049] After a single point is compacted to the required standard, the device moves to the next point and repeats the above-mentioned automated process of pre-setting, compaction, monitoring, and compensation until the construction of the entire area is completed, achieving highly uniform and high-quality foundation treatment.

[0050] Specific process: Turn on the power supply 3 and check the operating status of the first motor 6 and the second motor 12 through the control panel 4 to ensure that the motors start and stop normally, rotate in the correct direction, and that the transmission between the ball screw 7 and the ball sleeve 8 is smooth.

[0051] According to the design requirements for the treatment of collapsible loess foundation, the target compaction depth parameter is input on the control panel 4. The control panel 4 transmits the command to the first motor 6. The first motor 6 drives the ball screw 7 to rotate. The ball screw sleeve 8 rises and falls vertically along the screw under the constraint of the limit slider and the groove of the fixed frame 5, driving the lifting rod 9 and the lifting frame 11 to move synchronously until the lifting frame 11 descends to the height position that matches the target compaction depth. Then the first motor 6 stops running and locks its position.

[0052] The second motor 12 is started by controlling panel 4. The second motor 12 drives the take-up and release wheel 13 to rotate in the forward direction, releasing the steel wire 14. The tamping hammer 15 falls vertically along the slide groove of the device shell 1 under the action of gravity until the bottom of the tamping hammer 15 contacts the surface of the collapsible loess foundation. The second motor 12 stops releasing the steel wire 14 and remains in a braking state, completing the positioning of the tamping hammer 15.

[0053] Control panel 4 issues a compaction command, the second motor 12 releases its brake and rotates in the opposite direction, driving the take-up and release wheel 13 to retract the steel wire 14 and lift the compaction hammer 15 to the set height. When the compaction hammer 15 is lifted to the position, the second motor 12 stops again and releases its brake. The compaction hammer 15 falls freely under its own weight, impacting and compacting the foundation. According to the design requirements, the lifting and falling process can be repeated multiple times to achieve the expected compaction effect.

[0054] During the compaction process, the distance between the compaction points and the ground is monitored in real time. The ground settlement is then calculated based on this data. When the settlement accumulates to a set threshold (this threshold is not the final threshold for compaction, but is only used to control the distance of a single tamping hammer 15 falling), the first motor 6 is automatically controlled to drive the lifting frame 11 downwards by the ball screw 7 transmission mechanism to make a corresponding fine adjustment.

[0055] After a single point is compacted, the first motor 6 is reversed via the control panel 4, which drives the lifting frame 11 and the compaction hammer 15 to rise and reset. At the same time, the track 2 is operated to move the device to the next compaction point. The above process is repeated until the foundation compaction work of the entire construction area is completed. Finally, the power supply 3 is turned off, and the device is cleaned and maintained.

[0056] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A device for controlling the compaction depth of foundation in collapsible loess areas, characterized in that, include: The device casing, depth control mechanism, and compaction mechanism; The device housing includes a top plate and two side plates, with the side plates located on the lower parts of both sides of the top plate, and a receiving cavity between the side plates; The depth control mechanism includes a lifting module and a lifting frame. The lifting module is installed on the top plate of the device housing, and the lifting frame is installed at the bottom end of the lifting module and located inside the receiving cavity. The compaction mechanism includes a line-laying module and a compaction hammer. The line-laying module is installed in the lifting frame, and the compaction hammer is connected to the bottom of the line-laying module.

2. The foundation compaction depth control device in collapsible loess areas as described in claim 1, characterized in that, The lifting module includes a fixed frame, a lifting rod, a first motor, and a ball screw nut assembly. The top plate has a slot starting from the middle, and the fixed frame is fixedly installed in the slot. The first motor is installed on the top of the fixed frame, and the lifting rod is connected to the first motor through the ball screw nut assembly. The lifting frame is installed at the bottom of the lifting rod.

3. The foundation compaction depth control device in collapsible loess areas as described in claim 2, characterized in that, The fixed frame includes two parallel fixed plates, which are mounted on the top plate via L-shaped mounting plates. The lower end of the lifting rod is connected to the lifting frame via an L-shaped mounting plate.

4. The foundation compaction depth control device in collapsible loess areas as described in claim 2, characterized in that, The ball screw nut assembly includes a ball screw and a ball sleeve. The top end of the ball screw is connected to the output shaft of the first motor, and the bottom end is rotatably mounted on a fixed frame. The ball sleeve is mounted on the ball screw, and the lifting rod is fixedly mounted on the ball sleeve.

5. The foundation compaction depth control device in collapsible loess areas as described in claim 1, characterized in that, The wire feeding module includes a second motor, a take-up and feed wheel, and a steel wire. The second motor is installed in the lifting frame, the take-up and feed wheel is installed on the output shaft of the second motor, and the steel wire is wound on the take-up and feed wheel. The bottom of the lifting frame has a hole for the steel wire to pass through, and the lower end of the steel wire is connected to a tamping hammer.

6. The foundation compaction depth control device in collapsible loess areas as described in claim 1, characterized in that, Guide mechanisms are provided between the two sides of the tamping hammer and the inner sides of the two side plates.

7. The foundation compaction depth control device in collapsible loess areas as described in claim 1, characterized in that, The outer shell of the device is U-shaped, and tracks are provided at the bottom of both side plates.

8. The foundation compaction depth control device in collapsible loess areas as described in claim 1, characterized in that, A laser rangefinder is installed on the inner side of the side plate of the device housing. The laser rangefinder is used to detect the settlement of the ground corresponding to the tamping hammer.

9. The foundation compaction depth control device in collapsible loess areas as described in claim 1, characterized in that, The power supply and control panel are located on one side panel of the device housing.

10. A compaction method for a foundation compaction depth control device in collapsible loess areas as described in any one of claims 1-9, characterized in that, Includes the following processes: The depth control mechanism lowers and locks the lifting frame via the lifting module; The line-laying module lays out the line, and the tamping hammer falls vertically under the action of gravity to compact the ground. The line-laying module then retracts the line and lifts the tamping hammer to the set height, repeating the lifting and falling process. During continuous compaction, the ground distance at the compaction point is monitored in real time, the ground settlement is calculated, and when the settlement reaches the set threshold, the lifting frame is adjusted accordingly to keep the effective drop distance of the compaction hammer within the preset range. After the compaction work at a single point is completed, move to the next compaction point and repeat the above process until the entire construction area is completed.

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