Deep soil displacement monitoring device and method based on LVDT displacement sensor

Abstract

The invention provides a deep soil displacement monitoring device and monitoring method based on an LVDT displacement sensor, and belongs to the technical field of rock engineering monitoring, the deep soil displacement monitoring device comprises a soil retaining box, the LVDT displacement sensor, a gear transmission device and a monitoring device, the LVDT displacement sensor and the gear transmission device are connected and arranged in the soil retaining box, the monitoring device is arranged on the ground, and the soil retaining box is connected with the LVDT displacement sensor. The soil retaining box is arranged in a deep soil body, the measuring end of the LVDT displacement sensor is arranged outside the soil retaining box, the LVDT displacement sensor has the freedom degree of circumferential movement and linear movement in the soil retaining box, the monitoring device controls the LVDT displacement sensor and the gear transmission device to operate, and therefore soil body displacement monitoring can be conducted on different positions. The deep soil displacement monitoring device based on the LVDT displacement sensor and the monitoring method have the technical effects of simple structure, small required site, low cost, no influence of soil pressure and underground water, accurate monitoring and high practicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of rock engineering monitoring. More specifically, it relates to a deep soil displacement monitoring device and monitoring method based on an LVDT displacement sensor. Background Technique

[0002] In the field of rock engineering monitoring, the deformation (geometry) monitoring of rock and soil masses is an extremely important part. In deformation monitoring, since displacement can more intuitively reflect the deformation information of rock and soil masses, it often becomes an important factor that cannot be ignored in rock and soil deformation monitoring.

[0003] The existing rock and soil displacement monitoring methods mainly focus on surface displacement monitoring, and it is impossible to comprehensively grasp the dynamic deformation characteristics of rock and soil masses. Therefore, it is necessary to conduct in-depth displacement monitoring of rock and soil masses. In addition to inclinometers, optical fibers, and MEMS sensors that can be applied to in-depth displacement monitoring, LVDT displacement sensors can also be used to monitor the in-depth displacement of soil masses. LVDT displacement sensors are widely used. They are often used to detect vibrations, conduct pressure tests, measure the operation of actuators, etc. However, since LVDT displacement sensors can only be used to reflect displacement changes in a straight line direction, it is urgent to find a deep soil displacement monitoring device based on LVDT displacement sensors, which has the advantages that the LVDT displacement sensor can be used not only in a straight line direction and can act underground for a long time without being affected by underground seepage. Summary of the Invention

[0004] The purpose of the present invention is to provide a deep soil displacement monitoring device and monitoring method based on an LVDT displacement sensor, aiming to solve the technical problem that LVDT displacement sensors can only be used to reflect displacement changes in a straight line direction and cannot be used for monitoring the in-depth position of soil masses in rock engineering.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a deep soil displacement monitoring device based on an LVDT displacement sensor, including:

[0006] A retaining box, which is hollow inside, has two top holes spaced apart at the top and a bottom hole at the bottom. The retaining box is used to extend into the deep part of the soil mass;

[0007] An LVDT displacement sensor is arranged inside the retaining box and is electrically connected to a first wire harness. The measuring end of the LVDT displacement sensor passes through the bottom hole and is used to measure the in-depth displacement of the soil mass;

[0008] A gear transmission device is provided inside the retaining soil box and is electrically connected to a second wire harness. The first wire harness and the second wire harness respectively pass through the two top holes in a one-to-one correspondence. The LVDT displacement sensor is connected to the gear transmission device, and the gear transmission device is used to drive the LVDT displacement sensor to move within the range of the bottom hole for monitoring soil displacement at different positions.

[0009] A monitoring device is located on the ground and is electrically connected to the first wire harness and the second wire harness respectively. The monitoring device has a control module adapted to control the operation of the gear transmission device and the LVDT displacement sensor, and also has a receiving module adapted to receive the deep soil displacement data information monitored by the LVDT displacement sensor.

[0010] In a possible implementation manner, the retaining soil box is a semi-closed cubic structure, and the retaining soil box is hermetically connected to the first wire harness and the second wire harness respectively.

[0011] In a possible implementation manner, the gear transmission device is electrically driven, and the monitoring device is used to control the rotation speed of the gear transmission device.

[0012] In a possible implementation manner, the gear transmission device includes:

[0013] A first gear transmission component is electrically connected to the monitoring device through the second wire harness. The monitoring device is used to control the operation of the first gear transmission component, and the first gear transmission component has a degree of freedom of rotating circumferentially, and its operation is controlled by the monitoring device.

[0014] A second gear transmission component is electrically connected to the monitoring device through the second wire harness. The monitoring device is used to control the operation of the second gear transmission component, and the second gear transmission component has a degree of freedom of moving vertically, and its operation is controlled by the monitoring device.

[0015] A transverse transmission rod is connected to the first gear transmission component and is connected to the LVDT displacement sensor. The transverse transmission rod has a degree of freedom of rotating circumferentially and is used to drive the LVDT displacement sensor to move circumferentially within the bottom hole.

[0016] A vertical transmission rod is connected to the second gear transmission component and is connected to the LVDT displacement sensor. The vertical transmission rod has a degree of freedom of moving vertically and is used to drive the LVDT displacement sensor to move vertically within the bottom hole.

[0017] In a possible implementation, both the first gear transmission assembly and the second gear transmission assembly include a driver and a gear transmission member, and the two gear transmission members respectively have a degree of freedom of circumferential rotational movement and a degree of freedom of vertical movement.

[0018] In a possible implementation, two buckles are connected to both the transverse transmission rod and the vertical transmission rod, and the two buckles are fixedly connected to the LVDT displacement sensor.

[0019] In a possible implementation, the material of the retaining box is a non-magnetic material and its density is greater than the density of water.

[0020] In a possible implementation, the LVDT displacement sensor includes a housing and a cylindrical ferromagnetic soft iron core disposed inside the housing and easy to be magnetized. A push rod that slides axially along the housing is provided inside the housing. Two ends of the push rod are respectively placed inside and outside the housing. The ferromagnetic soft iron core is connected to the push rod. A probe is connected to the outer end of the push rod. When the probe moves, the ferromagnetic soft iron core outputs a voltage. By observing the increase or decrease of the voltage, the moving direction and distance of the ferromagnetic soft iron core are determined, and then the linear displacement that occurs is measured.

[0021] In a possible implementation, the top hole is a wire passing hole, a sealing ring is sleeved in the wire passing hole, both the first wire harness and the second wire harness pass through the sealing ring, and the sealing ring is hermetically connected to the first wire harness and the second wire harness respectively.

[0022] The beneficial effects of a deep soil displacement monitoring device based on an LVDT displacement sensor provided by the present invention are as follows: Compared with the prior art, the deep soil displacement monitoring device based on an LVDT displacement sensor of the present invention includes a soil retaining box, an LVDT displacement sensor, a gear transmission device, and a monitoring device. The inside of the soil retaining box is hollow, and two top holes are spaced apart at the top, and a bottom hole is provided at the bottom. The soil retaining box is used to extend into the deep part of the soil; the LVDT displacement sensor is arranged inside the soil retaining box and is electrically connected to a first wire harness. The measuring end of the LVDT displacement sensor passes through the bottom hole and is used to measure the deep soil displacement; the gear transmission device is arranged inside the soil retaining box and is electrically connected to a second wire harness. The first wire harness and the second wire harness respectively pass through the two top holes in a one-to-one correspondence. The LVDT displacement sensor is connected to the gear transmission device. The gear transmission device is used to drive the LVDT displacement sensor to move within the range of the bottom hole to monitor the soil displacement at different positions; the monitoring device is located on the ground and is electrically connected to the first wire harness and the second wire harness respectively. The monitoring device has a control module suitable for controlling the operation of the gear transmission device and the LVDT displacement sensor, and also has a receiving module suitable for receiving the deep soil displacement data information monitored by the LVDT displacement sensor, solving the technical problem that the LVDT displacement sensor can only be used to reflect the displacement change in the linear direction and cannot be used for the deep soil position monitoring of rock engineering. It has the technical effects of being able to monitor the displacement at different positions of the deep soil, being able to reflect the displacement change in the linear direction, and being able to reflect the displacement change in other directions, and can act underground for a long time without being affected by underground seepage.

[0023] The present invention also provides a deep soil displacement monitoring method based on an LVDT displacement sensor, including the following steps:

[0024] Set up a gear transmission device, an LVDT displacement sensor, and a monitoring device, and connect the gear transmission device to the LVDT displacement sensor;

[0025] Set up a soil retaining box so that the inside of the soil retaining box is hollow;

[0026] Place the gear transmission device and the LVDT displacement sensor inside the soil retaining box, and electrically connect the gear transmission device and the LVDT displacement sensor to the monitoring device. The measuring end of the LVDT displacement sensor extends out from the bottom of the soil retaining box to measure the deep soil displacement;

[0027] Place the soil retaining box at a deep position in the drill hole so that the LVDT displacement sensor has degrees of freedom of vertical movement and circumferential movement in the horizontal plane inside the soil retaining box;

[0028] Enable the monitoring device to control the operation of the gear transmission device and the LVDT displacement sensor, so that the LVDT displacement sensor can monitor the deep soil displacement at different positions.

[0029] The beneficial effects of a deep soil displacement monitoring method based on an LVDT displacement sensor provided by the present invention are as follows: compared with the prior art, the steps are simple, the required site is small, the cost is low, it is not affected by soil pressure and groundwater, the monitoring is accurate, and the practicality is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 It is a schematic structural diagram of a deep soil displacement monitoring device based on an LVDT displacement sensor provided by an embodiment of the present invention;

[0032] Figure 2 It is a schematic structural diagram of the gear transmission device of a deep soil displacement monitoring device based on an LVDT displacement sensor provided by an embodiment of the present invention;

[0033] Figure 3 It is a schematic structural diagram of the LVDT displacement sensor of a deep soil displacement monitoring device based on an LVDT displacement sensor provided by an embodiment of the present invention;

[0034] Figure 4 It is an exploded schematic structural diagram of the LVDT displacement sensor of a deep soil displacement monitoring device based on an LVDT displacement sensor provided by an embodiment of the present invention;

[0035] Figure 5 It is a schematic structural diagram of the soil retaining box of a deep soil displacement monitoring device based on an LVDT displacement sensor provided by an embodiment of the present invention;

[0036] Figure 6 It is a schematic structural diagram of the transverse transmission rod of a deep soil displacement monitoring device based on an LVDT displacement sensor provided by an embodiment of the present invention;

[0037] Figure 7 It is a schematic structural diagram of the vertical transmission rod of a deep soil displacement monitoring device based on an LVDT displacement sensor provided by an embodiment of the present invention.

[0038] Description of the reference numerals:

[0039] 1. Retaining soil box; 2. LVDT displacement sensor; 3. Gear transmission device; 4. Hollow cavity; 5. Top hole; 6. Bottom hole; 7. Horizontal transmission rod; 8. Vertical transmission rod; 9. Snap; 10. Ferromagnetic soft iron core; 11. Push rod; 12. Probe; 13. Primary coil; 14. Secondary winding. Detailed implementation manner

[0040] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] Please refer to Figures 1 to 7 simultaneously, and a deep soil displacement monitoring device based on an LVDT displacement sensor provided by the present invention will be described. The deep soil displacement monitoring device based on an LVDT displacement sensor includes a retaining soil box 1 and a monitoring device. The inside of the retaining soil box 1 is hollow, that is, it has a hollow cavity 4. Two top holes 5 are spaced apart at the top, and a bottom hole 6 is opened at the bottom. The retaining soil box 1 is used to extend into the deep part of the soil; the LVDT displacement sensor 2 is arranged inside the retaining soil box 1 and is electrically connected to a first wire harness. The measuring end of the LVDT displacement sensor 2 passes through the bottom hole 6 and is used to measure the deep soil displacement; the gear transmission device 3 is arranged inside the retaining soil box 1 and is electrically connected to a second wire harness. The first wire harness and the second wire harness respectively pass through the two top holes 5 one by one. The LVDT displacement sensor 2 is connected to the gear transmission device 3. The gear transmission device 3 is used to drive the LVDT displacement sensor 2 to move within the range of the bottom hole 6 to monitor the soil displacement at different positions; the monitoring device is located on the ground and is electrically connected to the first wire harness and the second wire harness respectively. The monitoring device has a control module suitable for controlling the operation of the gear transmission device 3 and the LVDT displacement sensor 2, and also has a receiving module suitable for receiving the deep soil displacement data information monitored by the LVDT displacement sensor 2.

[0042] The deep soil displacement monitoring device based on an LVDT displacement sensor provided by the present invention, compared with the prior art, places the LVDT displacement sensor 2 and the gear transmission device 3 inside the retaining soil box 1, places the retaining soil box 1 inside the deep soil, and enables the monitoring device to control the operation of the LVDT displacement sensor 2 and the gear transmission device 3, solving the technical problem that the LVDT displacement sensor 2 can only be used to reflect the displacement change in the linear direction and cannot be used for the deep soil position monitoring of rock engineering. It has the technical effects of being able to monitor the displacement of different positions of deep soil, being able to reflect the displacement change in the linear direction, and being able to reflect the displacement change in other directions, and can act underground for a long time without being affected by underground seepage.

[0043] The LVDT displacement sensor 2 in the present invention, namely a linear variable differential transformer, can achieve a measurement accuracy at the micron level, can accurately reflect the displacement change in the linear direction, and can determine the displacement amount along the straight line direction by observing the increase or decrease of the voltage output and its negative or positive value. It can store electromagnetic energy and convert a certain form of energy into a readable signal for describing the axial movement of an object.

[0044] The gear transmission device 3 can drive the LVDT displacement sensor 2 to move inside the retaining box 1, and thus can monitor displacements in different directions. The diameter of the bottom hole 6 is relatively large, and the LVDT displacement sensor 2 can perform cyclic measurements within the range of the bottom hole 6. When the retaining box 1 is placed horizontally, the LVDT displacement sensor 2 can perform circumferential rotational movement in the horizontal plane and can also move vertically, so as to monitor displacements at different positions of the deep soil mass. The monitoring results will be transmitted to the monitoring device through the first wire harness. The monitoring device can control the operation of the LVDT displacement sensor 2 and the gear transmission device 3, and can also receive the data information monitored by the LVDT displacement sensor 2. The monitoring device has a display, and the displacement information of the deep soil mass can be displayed through the display. The monitoring device can be selected from the existing technologies and can play roles such as controlling and receiving information. It can be operated and controlled on the ground, so as to monitor the displacements of soil masses at different positions. The LVDT displacement sensor 2 can be selected from existing technology products, can achieve the displacement monitoring of the soil mass, has a relatively high monitoring accuracy, and can display the monitoring results in real time through the monitoring device.

[0045] In some embodiments, please refer to Figures 1 to 7 , the retaining box 1 is a semi-closed cubic structure, and the retaining box 1 is hermetically connected to the first wire harness and the second wire harness respectively. The lengths of the first wire harness and the second wire harness should meet the usage requirements. The sealing effect should be ensured between the wire harness and the retaining box 1.

[0046] In some embodiments, please refer to Figures 1 to 7 , the gear transmission device 3 is electrically driven, and the monitoring device is used to control the rotation speed of the operation of the gear transmission device 3. The monitoring device can provide power for the gear transmission device 3, can drive and control the operation of the gear transmission device 3, and thus can drive the LVDT displacement sensor 2 to move. The moving speed etc. of the LVDT displacement sensor 2 are all controlled by the monitoring device, so as to achieve the cyclic measurement of the LVDT displacement sensor 2 within the range of the bottom hole 6.

[0047] In some embodiments, please refer to Figures 1 to 7, the gear transmission device 3 includes a first gear transmission assembly, a second gear transmission assembly, a transverse transmission rod 7 and a vertical transmission rod 8. The first gear transmission assembly is electrically connected to the monitoring device through a second wire harness. The monitoring device is used to control the operation of the first gear transmission assembly. The first gear transmission assembly has a degree of freedom of rotating circumferentially, and its operation is controlled by the monitoring device. The second gear transmission assembly is electrically connected to the monitoring device through a second wire harness. The monitoring device is used to control the operation of the second gear transmission assembly. The second gear transmission assembly has a degree of freedom of moving vertically, and its operation is controlled by the monitoring device. The transverse transmission rod 7 is connected to the first gear transmission assembly and is connected to the LVDT displacement sensor 2. The transverse transmission rod 7 has a degree of freedom of rotating circumferentially and is used to drive the LVDT displacement sensor 2 to move circumferentially in the bottom hole 6. The vertical transmission rod 8 is connected to the second gear transmission assembly and is connected to the LVDT displacement sensor 2. The vertical transmission rod 8 has a degree of freedom of moving vertically and is used to drive the LVDT displacement sensor 2 to move vertically in the bottom hole 6. By operating on the monitoring device, the operations of the first gear transmission assembly and the second gear transmission assembly can be controlled respectively, so as to drive the LVDT displacement sensor 2 to move.

[0048] In some embodiments, please refer to Figures 1 to 7 , both the first gear transmission assembly and the second gear transmission assembly include a driver (which can be a kind of motor or reduction motor, etc., and is a kind of electric driving part) and a gear transmission part. The two sets of gear transmission parts respectively have a degree of freedom of rotating circumferentially and a degree of freedom of moving vertically. The driver is electrically connected to the monitoring device, that is, the monitoring device can control the operation of the driver, so as to drive the LVDT displacement sensor 2 to move. One set of gear transmission assembly has an execution end that can rotate circumferentially, and the other set of gear transmission assembly has an execution end that can move vertically. The LVDT displacement sensor 2 is provided in two sets, which are respectively connected to the two sets of gear transmission parts. The two sets of LVDT displacement sensors 2 have their own operating trajectories, can operate alternately, and do not affect each other during operation. The gear transmission part that moves circumferentially can be a kind of gear. The power output end of the driver is connected to the gear shaft, and can drive the gear to rotate circumferentially. The transverse transmission rod 7 is connected to the end of the gear, so as to drive the transverse transmission rod 7 to move circumferentially, so as to drive the LVDT displacement sensor 2 to move circumferentially within the range of the bottom hole 6. The gear transmission part that moves vertically includes a gear and a rack that mesh with each other. The gear shaft of the gear is connected to the power output end of the driver. The driver drives the gear to rotate. When the gear rotates, it drives the rack to move linearly vertically. The vertical transmission rod 8 is connected to the rack, so as to move vertically, and further drive the LVDT displacement sensor 2 to move vertically in the bottom hole 6.

[0049] To ensure the stability and connection effect after connection, in some embodiments, please refer to Figures 1 to 7, both the horizontal transmission rod 7 and the vertical transmission rod 8 are connected with two buckles 9, and the two buckles 9 are fixedly connected with the LVDT displacement sensor 2. The connection of the buckles 9 is relatively stable, and phenomena such as unhooking will not occur, ensuring that it will not fall off due to the action of gravity.

[0050] In some embodiments, please refer to Figures 1 to 7 , the retaining box 1 is made of non-magnetic material and has a density greater than that of water. The retaining box 1 can play a role in protecting the LVDT displacement sensor 2 and the gear transmission device 3.

[0051] In some embodiments, please refer to Figures 1 to 7 , the LVDT displacement sensor 2 includes a housing and a cylindrical ferromagnetic soft iron core 10 that is easy to magnetize and is provided inside the housing. There is a push rod 11 that slides axially inside the housing. Both ends of the push rod 11 are placed inside and outside the housing. The ferromagnetic soft iron core 10 is connected to the push rod 11, and a probe 12 is connected to the outer end of the push rod 11. When the probe 12 moves, the ferromagnetic soft iron core 10 outputs a voltage. By observing the increase and decrease of the voltage, the moving direction and distance of the ferromagnetic soft iron core 10 can be determined, and then the linear displacement that occurs can be measured. When the ferromagnetic soft iron core 10 moves from the original position, the static induced voltage changes. When it moves upward, it will cause a positive output voltage, and when it moves downward, it will cause a negative output voltage. At this time, by observing the increase or decrease of the voltage and its negative or positive value, the moving direction and distance of the ferromagnetic soft iron core 10 can be determined, and the linear displacement can be measured accordingly.

[0052] In some embodiments, please refer to Figures 1 to 7 , the top hole 5 is a wire passing hole, and a sealing ring is sleeved inside the wire passing hole. Both the first wire harness and the second wire harness pass through the sealing ring, and the sealing ring is hermetically connected to the first wire harness and the second wire harness respectively.

[0053] The present invention also provides a deep soil displacement monitoring method based on an LVDT displacement sensor, including the following steps:

[0054] Set up the gear transmission device 3, the LVDT displacement sensor 2 and the monitoring device, and connect the gear transmission device 3 with the LVDT displacement sensor 2;

[0055] Set up the retaining box 1 so that the inside of the retaining box 1 is hollow;

[0056] Place the gear transmission device 3 and the LVDT displacement sensor 2 inside the retaining box 1, and electrically connect the gear transmission device 3 and the LVDT displacement sensor 2 with the monitoring device. The measuring end of the LVDT displacement sensor 2 extends out from the bottom of the retaining box 1 to measure the deep soil displacement;

[0057] Place the retaining box 1 at a deep position inside the drill hole, so that the LVDT displacement sensor 2 has degrees of freedom of moving vertically and moving circumferentially in the horizontal plane inside the retaining box 1;

[0058] The monitoring device is used to control the operation of the gear transmission device 3 and the LVDT displacement sensor 2, so that the LVDT displacement sensor 2 can monitor the deep soil displacement at different positions.

[0059] The beneficial effects of a deep soil displacement monitoring method based on the LVDT displacement sensor 2 provided by the present invention are as follows: compared with the prior art, the steps are simple, the required site is small, the cost is low, it is not affected by soil pressure and groundwater, the monitoring is accurate, and the practicability is high.

[0060] Among them, after the connecting number, the retaining box 1 is placed in the borehole, and then the borehole is backfilled. The monitoring device is used to control the operation of the gear transmission device 3. The transverse transmission rod 7 can move circumferentially, and the vertical transmission rod 8 can move linearly vertically, so as to monitor the deep soil displacement at different positions.

[0061] The LVDT displacement sensor 2 is composed of three high-density glass-filled coils wound around a hollow non-magnetic insulating tube. The primary coil 13 is located in the center, and the other two are identical secondary windings 14 located on both sides of the primary coil 13. The differential part comes from the opposite phases of these two secondary coils, which are electrically 180 degrees apart from each other and are connected in series. The output generated by this connection is the voltage difference between these two secondary windings 14, and its accuracy reaches the nanometer level, which can accurately reflect subtle changes. The retaining box 1 in the present invention can be composed of two parts, or the upper and lower parts, which is convenient for assembly and disassembly, and convenient for installing the LVDT displacement sensor 2, the gear transmission device 3, etc.

[0062] The technical effects of the present invention are as follows:

[0063] 1) The LVDT displacement sensor 2 can reach the micron level, can reflect subtle change amounts, can timely reflect the changes of soil displacement, and is convenient for dealing with and monitoring emergencies.

[0064] 2) Due to the influence of the borehole depth, groundwater seeps out. The function of the retaining box 1 is to avoid the failure to reach the target monitoring depth due to the buoyancy of groundwater, and also to ensure the problem of malfunction caused by the LVDT displacement sensor 2 being close to magnetic objects.

[0065] 3) The materials used in the present invention are easy to obtain and convenient to manufacture. In addition, the cost is low. Through a low cost, the LVDT displacement sensor 2 can reach the specified depth. The first wire harness and the second wire harness can also avoid the influence of soil pressure. The present invention is not affected by groundwater and does not cause a magnetic field influence on the MEMS sensor itself.

[0066] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A deep soil displacement monitoring device based on an LVDT displacement sensor, characterized in that Comprising: A retaining soil box, which is hollow inside, has two top holes spaced apart at the top, and a bottom hole at the bottom. The retaining soil box is used to extend deep into the soil body; An LVDT displacement sensor, which is arranged inside the retaining soil box, is electrically connected with a first wire harness. The measuring end of the LVDT displacement sensor passes through the bottom hole and is used to measure the displacement of the deep soil body; A gear transmission device, which is arranged inside the retaining soil box, is electrically connected with a second wire harness. The first wire harness and the second wire harness respectively pass through the two top holes one by one. The LVDT displacement sensor is connected with the gear transmission device. The gear transmission device is used to drive the LVDT displacement sensor to move within the range of the bottom hole so as to monitor the soil body displacement at different positions; A monitoring device, which is located on the ground, is electrically connected with the first wire harness and the second wire harness respectively. The monitoring device has a control module suitable for controlling the operation of the gear transmission device and the LVDT displacement sensor, and also has a receiving module suitable for receiving the deep soil body displacement data information monitored by the LVDT displacement sensor.

2. The deep soil displacement monitoring device based on an LVDT displacement sensor according to claim 1, wherein The retaining soil box is a semi-closed cube structure, and the retaining soil box is hermetically connected with the first wire harness and the second wire harness respectively.

3. The deep soil displacement monitoring device based on an LVDT displacement sensor according to claim 1, wherein, The gear transmission device is driven by electricity, and the monitoring device is used to control the rotation speed of the gear transmission device.

4. The deep soil displacement monitoring device based on an LVDT displacement sensor according to claim 1, characterized in that The gear transmission device includes: A first gear transmission component, which is electrically connected with the monitoring device through the second wire harness. The monitoring device is used to control the operation of the first gear transmission component. The first gear transmission component has a degree of freedom of rotating circumferentially, and its operation is controlled by the monitoring device; A second gear transmission component, which is electrically connected with the monitoring device through the second wire harness. The monitoring device is used to control the operation of the second gear transmission component. The second gear transmission component has a degree of freedom of moving vertically, and its operation is controlled by the monitoring device; A transverse transmission rod, which is connected to the first gear transmission component and is connected with the LVDT displacement sensor. The transverse transmission rod has a degree of freedom of rotating circumferentially and is used to drive the LVDT displacement sensor to move circumferentially in the bottom hole; A vertical transmission rod, which is connected to the second gear transmission component and is connected with the LVDT displacement sensor. The vertical transmission rod has a degree of freedom of moving vertically and is used to drive the LVDT displacement sensor to move vertically in the bottom hole.

5. The deep soil displacement monitoring device based on an LVDT displacement sensor according to claim 4, characterized in that, Both the first gear transmission component and the second gear transmission component include a driver and a gear transmission part. The two gear transmission parts respectively have a degree of freedom of rotating circumferentially and a degree of freedom of moving vertically.

6. The deep soil displacement monitoring device based on an LVDT displacement sensor according to claim 4, wherein Both the transverse transmission rod and the vertical transmission rod are connected with two buckles, and the two buckles are fixedly connected with the LVDT displacement sensor.

7. The deep soil displacement monitoring device based on an LVDT displacement sensor according to claim 1, wherein The material of the retaining soil box is a non-magnetic material and its density is greater than the density of water.

8. The deep soil displacement monitoring device based on an LVDT displacement sensor according to claim 1, characterized in that, The LVDT displacement sensor includes a housing and a cylindrical ferromagnetic soft iron core disposed inside the housing and easily magnetizable. A push rod that slides axially along the housing is provided inside the housing. Both ends of the push rod are respectively placed inside and outside the housing. The ferromagnetic soft iron core is connected to the push rod. A probe is connected to the outer end of the push rod. When the probe moves, the ferromagnetic soft iron core outputs a voltage. By observing the increase or decrease of the voltage, the moving direction and distance of the ferromagnetic soft iron core are determined, and thus the linear displacement that occurs is measured.

9. The deep soil displacement monitoring device based on an LVDT displacement sensor according to claim 1, characterized in that The top hole is a wire passing hole, and a sealing ring is sleeved inside the wire passing hole. Both the first wire harness and the second wire harness pass through the sealing ring, and the sealing ring is hermetically connected to the first wire harness and the second wire harness respectively.

10. A deep soil displacement monitoring method based on an LVDT displacement sensor, characterized in that, It includes the following steps: Set up a gear transmission device, an LVDT displacement sensor, and a monitoring device, and connect the gear transmission device to the LVDT displacement sensor; Set up a soil retaining box with a hollow interior; Place the gear transmission device and the LVDT displacement sensor inside the soil retaining box, and electrically connect the gear transmission device and the LVDT displacement sensor to the monitoring device. The measuring end of the LVDT displacement sensor extends out from the bottom of the soil retaining box to measure the displacement of deep soil; Place the soil retaining box at a deep position inside the borehole, and enable the LVDT displacement sensor to have degrees of freedom of vertical movement and circumferential movement in the horizontal plane inside the soil retaining box; Enable the monitoring device to control the operation of the gear transmission device and the LVDT displacement sensor so that the LVDT displacement sensor can monitor the displacement of deep soil at different positions.

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