A device and implementation method for measuring the deformation of the wall body of a fully recyclable foundation pit retaining structure

Abstract

The present invention discloses a fully recoverable deformation measurement device and implementation method for the retaining structure wall of a foundation pit, which relates to the technical field of steel sheet pile measurement for foundation pits. It includes steel sheet piles and a protective pipe fixed to the inner wall of the steel sheet piles. A goniometer is installed at the top of the protective pipe, and a drill bit is connected to the bottom. Ultrasonic transmitters and receiving probes are arranged in groups at each measuring point of the steel sheet piles. A metal sheet is rotatably connected inside the protective pipe to maintain a vertical state and reflect ultrasonic waves. The goniometer includes a goniometer cylinder filled with a liquid medium, and a suspended thin sheet is arranged in the liquid medium. An annular laser light strip is fixed on the upper side of the goniometer cylinder, and a multi-point laser sensor is arranged inside the annular laser light strip. The present invention can be integrated with the steel sheet piles and driven into the ground together, and can measure the inclination angle and bending deformation curve of the steel sheet piles in real time and output values, and can issue an alarm in time when the allowable inclination angle is exceeded.

Description

Technical Field

[0001] The present invention relates to the technical field of deformation measurement of fully recyclable foundation pit retaining walls, and in particular to a device and implementation method for measuring the deformation of the wall body of a fully recyclable foundation pit retaining structure. Background Technique

[0002] In recent years, the fully recyclable foundation pit support technology has achieved rapid development. The fully recyclable support technology includes fully recyclable retaining and bracing structures. The fully recyclable retaining structures mainly include steel sheet piles, and composite steel piles formed by combining steel sheet piles with H-shaped steel or steel pipe piles. The fully recyclable retaining structures are generally driven into the soil by means of static pressure, hammering, etc. During subsequent foundation pit excavation, the soil outside the pit acts on the retaining structure, causing the retaining structure to deform.

[0003] According to the provisions of GB50497-2019 "Technical Standard for Monitoring of Building Foundation Pit Engineering", the deformation of the wall body of the retaining structure should be monitored for foundation pit engineering with a safety level of above grade two. Since the current fully recyclable retaining structures are all steel standard components, the commonly used PVC inclinometers in engineering cannot be driven into the ground simultaneously with the fully recyclable retaining structures. For foundation pits using fully recyclable retaining structures such as steel sheet piles and composite steel piles, the wall body deformation is basically not measured, which does not meet the requirements of the current national standards and is even less able to grasp the working behavior of the fully recyclable retaining structures.

[0004] If a split construction method is adopted, the inclinometer should be installed first. Since the construction of the fully recyclable retaining structure is a soil-extrusion process, the inclinometer is easily damaged. Based on the materials of ordinary inclinometers, there are also problems such as pipe body rupture, and the true deformation state of the wall body cannot be realized.

[0005] In the prior art, there has been a method of combining steel sheet piles with inclinometers. For example, a grating is fixed on the inclinometer, and the strain of the steel sheet pile is measured through the common deformation of the optical fiber and the steel sheet pile. However, the initial inclination angle of the steel sheet pile when it is driven in cannot be measured by the optical fiber, nor can the steel sheet pile be corrected and adjusted in a timely manner. CN113063373A discloses a coaxial positioning device for detecting the inclination angle of pipe piles that can simultaneously measure the azimuth angle. The principle of its laser parallel assembly is to use a laser to indicate the inclination azimuth angle on the dial, and the laser assembly freely slides to the lowest angle in the oil storage tank for measurement. If the inclination angle is too small, there may be a situation where the sliding is not in place, and the actual azimuth angle cannot be accurately measured.

[0006] CN113970303B discloses an ultrasonic-based profile detection system and method for branch-disk piles, which uses the ultrasonic transmission method to detect characteristics such as the ultrasonic travel time and waveform of the medium between conduits, and accordingly judges the outer contour shape of the pile body. The ultrasonic propagation situation is complex, and the energy will be weakened during the transmission process. Although some adjustments and corrections are made using formulas, there are still certain errors. During the measurement process, the positions of the transmitting transducer and the receiving transducer need to be moved, and only one set of transducers can be used to transmit ultrasonic waves simultaneously, otherwise interference will be generated during the transmission process. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a fully recoverable foundation pit retaining structure wall deformation measurement device and implementation method, which can be combined with steel sheet piles and driven into the ground together, and can measure the inclination angle and bending deformation curve of the steel sheet piles in real time and output numerical values, and can issue an alarm in time when the allowable inclination angle is exceeded.

[0008] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0009] In a first aspect, an embodiment of the present invention provides a fully recoverable foundation pit retaining structure wall deformation measurement device, including a steel sheet pile and a protective tube fixed to the inner wall of the steel sheet pile. A angle measurement device is installed at the top of the protective tube, and a drill bit is connected to the bottom; ultrasonic transmitters and receiving probes are arranged in groups at each measurement point of the steel sheet pile, and a metal sheet is rotatably connected inside the protective tube to maintain a vertical state and reflect ultrasonic waves.

[0010] The angle measurement device includes an angle measurement cylinder filled with a liquid medium, and a suspended thin sheet is arranged in the liquid medium; a ring-shaped laser light strip is fixed on the upper side of the angle measurement cylinder, and a multi-point laser sensor is arranged inside the ring-shaped laser light strip.

[0011] As a further implementation method, an alarm device is installed at the bottom of the protective tube.

[0012] As a further implementation method, the alarm device includes insulating sheets oppositely arranged on the inner walls of the steel sheet pile and the protective tube, and the transmitting and receiving cables connected to the ultrasonic transmitter and the receiving probe are pasted on both sides of the insulating sheet in two strands.

[0013] As a further implementation method, when the inclination angle of the steel sheet pile reaches the maximum allowable inclination angle, the bottom end of the metal steel sheet contacts the two circuits on the surface of the insulating sheet.

[0014] As a further implementation method, a signal converter is arranged on the upper side of the ring-shaped laser light strip, and the signal converter is used to process the reflected light received by the multi-point laser sensor.

[0015] As a further implementation, the signal converter is connected to the display through a cable.

[0016] As a further implementation, the metal sheet extends along the length direction of the protection tube.

[0017] As a further implementation, the liquid medium is water; the protection tube is made of PPR material.

[0018] In a second aspect, an embodiment of the present invention further provides an implementation method of a full-recovery foundation pit retaining structure wall deformation measurement device, using the measurement system, including:

[0019] When the steel sheet pile tilts, the angle measuring device tilts together. The suspended thin sheet therein always maintains a horizontal liquid level along with the liquid medium. After being energized, the annular laser light belt above the liquid level emits a circle of laser light towards the liquid level, and its reflected light is received by the multi-point laser sensor. Through signal converter processing, the height difference between two points in any direction of the diameter endpoints passing through the center of the circle is obtained, and thus the tilt angle is obtained.

[0020] When the steel sheet pile tilts, the metal sheet in the protection tube will rotate around the shaft and always remain vertically downward. After being energized, the ultrasonic transmitter emits ultrasonic waves around it, and the receiving probe receives the ultrasonic wave that reflects back the fastest. The horizontal displacement of each measuring point relative to the metal sheet is obtained from the time difference between the ultrasonic wave emission and return; it is transmitted to the single-chip microcomputer through the transmitting and receiving cable to calculate the tilt angle between each measuring point, and after being processed by the display cable, the real-time bending deformation curve of the steel sheet pile is displayed on the display.

[0021] As a further implementation, when the tilt angle of the steel sheet pile reaches the maximum allowable tilt angle, the bottom end of the metal sheet touches two circuits on the insulating sheet, making the circuit connected, so that a warning signal appears on the display.

[0022] The beneficial effects of the present invention are as follows:

[0023] (1) On the upper side of the angle measuring cylinder of the present invention, an annular laser light belt is fixed, and a multi-point laser sensor is arranged inside the annular laser light belt. The tilt angle of the steel sheet pile in any direction can be calculated according to the time difference between the laser light emission and return, and timely adjustment can be made according to the real-time displayed value. At the same time, it provides a reference angle for the bending deformation of the steel sheet pile; ultrasonic transmitters and receiving probes are installed at each measuring point of the steel sheet pile. The horizontal displacement of the measuring point relative to the metal sheet can be calculated according to the time difference between the ultrasonic wave emission and the fastest received wave, and then the tilt angle between the measuring points can be calculated to draw the bending deformation curve along the steel sheet pile.

[0024] (2) An alarm device is installed at the bottom of the protection tube of the present invention. Insulating sheets are respectively fixed on the protection tube and the steel sheet pile. The transmitting and receiving cables are divided into two strands and pasted on both sides of the insulating sheet. The cables are in an open circuit state on the insulating sheet. When the maximum inclination angle is reached, the bottom end of the metal sheet will contact the two strands of cables on the insulating sheet to form a circuit, so that a warning signal will appear on the display, facilitating a timely response. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The schematic diagrams in the specification forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0026] Figure 1 is a schematic diagram of the overall structure of the present invention according to one or more embodiments;

[0027] Figure 2 Schematic diagram of the angle measuring device structure of the present invention according to one or more embodiments;

[0028] Figure 3 Schematic diagram of the top of the protection tube of the present invention according to one or more embodiments;

[0029] Figure 4 Top view of the connection between the protection tube and the steel sheet pile of the present invention according to one or more embodiments;

[0030] Figure 5 Front view of the inside of the protection tube of the present invention according to one or more embodiments;

[0031] Figure 6 Top view of the alarm device of the present invention according to one or more embodiments;

[0032] Figure 7 Side view of the inside of the protection tube of the present invention according to one or more embodiments;

[0033] Figure 8 Schematic diagram of the inside of the protection tube in the bent state of the steel sheet pile of the present invention according to one or more embodiments;

[0034] Figure 9 Side view of the alarm device of the invention according to one or more embodiments.

[0035] Among them, 1. Steel sheet pile, 2. Protection tube, 3. Receiving probe, 4. Ultrasonic transmitter, 5. Metal sheet, 6. Rotating shaft, 7. Drill bit, 8. Angle measuring device, 9. Signal converter, 10. Ring laser light strip, 11. Multi-point laser sensor, 12. Suspended thin sheet, 13. Liquid medium, 14. Cable, 15. Top cover, 16. Transmitting and receiving cable, 17. Single-chip microcomputer, 18. Display cable, 19. Display, 20. Insulating sheet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] Example 1:

[0037] This embodiment provides a device for measuring the deformation of the wall body of a fully recycled foundation pit retaining structure. As Figure 1 shown, it includes a steel sheet pile 1, a protection pipe 2, an angle measuring device 8, a display 19, etc. The protection pipe 2 is fixed to the inner wall of the steel sheet pile 1 and is located at the middle position of the steel sheet pile 1, that is, at the position of the maximum deformation in the middle of the steel sheet pile 1. The protection pipe 2 is arranged along the length direction of the steel sheet pile 1. Taking the direction of construction of the steel sheet pile 1 as a reference, the end of the protection pipe 2 is connected to a drill bit 7. The drill bit 7 corresponds to the bottom of the steel sheet pile 1. By setting the drill bit 7, it is convenient for the protection pipe 2 to be driven into the ground together with the steel sheet pile 1.

[0038] As Figure 2 shown, a top cover 15 is installed at the top of the protection pipe 2, and the angle measuring device 8 is installed through the top cover 15, so that the angle measuring device 8 is located at the top of the protection pipe 2. In this embodiment, as Figure 3 shown, the cross-section of the protection pipe 2 is arc-shaped, such as semi-circular; the top of the protection pipe 2 has an inclined surface that slopes inward. The shape of the top cover 15 is adapted to that of the protection pipe 2. The edge of the top cover 15 has a certain inclination angle, which can coincide with the inclination angle of the port of the protection pipe 2, and the two are clamped together and welded for fixation.

[0039] Both the protection pipe 2 and the drill bit 7 in this embodiment are made of PPR material and can deform together with the steel sheet pile 1.

[0040] There is a certain distance between the top cover 15 and the top of the steel sheet pile 1 to facilitate the construction of the steel sheet pile 1. For example: a 50 cm gap is reserved between the top cover 15 and the top of the steel sheet pile 1. This distance can be adjusted adaptively according to the size of the protection pipe 2, the construction environment, etc.

[0041] As Figure 2 and Figure 7 shown, the angle measuring device 8 is arranged inside the top of the protection pipe 2 and includes an angle measuring cylinder body, a floating thin sheet 12, and a liquid medium 13. The angle measuring cylinder body in this embodiment is cylindrical, with a cavity inside. The angle measuring cylinder body is inscribed in the protection pipe 2; the inside of the angle measuring cylinder body is a closed cavity, which is filled with a liquid medium 13. A circular floating thin sheet 12 floats in the liquid medium 13. The diameter of the floating thin sheet 12 is adapted to the inner diameter of the angle measuring cylinder body and is slightly smaller than the inner diameter of the angle measuring cylinder body; the floating thin sheet 12 is used to prevent specular reflection of the laser.

[0042] As Figure 8As shown, due to the action of the liquid medium 13, when the steel sheet pile 1 is tilted, the angle measuring device 8 will also tilt accordingly, and the floating thin sheet 12 will always remain horizontal. In this embodiment, the liquid medium 13 is water, and the floating thin sheet 12 is a PVC thin sheet, and the PVC thin sheet can float in water. It can be understood that in other embodiments, other liquid media 13 and floating thin sheets 12 can also be used, as long as it can be ensured that the floating thin sheet 12 can float in the liquid medium 13.

[0043] An annular laser light strip 10 and a signal converter 9 are sequentially arranged at the top of the angle measuring cylinder body, as Figure 2 shown. A multi-point laser sensor 11 is arranged inside the annular laser light strip 10. The multi-point laser sensor 11 is connected to the signal converter 9 through a cable, and the signal converter 9 is connected to the display 19 through a cable 14; wherein, the diameter of the annular laser light strip 10 is smaller than the diameter of the floating thin sheet 12.

[0044] After the device is powered on, the annular laser light strip 10 above the liquid surface will emit a circle of laser light towards the liquid surface. Since the diameter of the annular laser light strip 10 is smaller than that of the floating thin sheet 12, although the floating thin sheet 12 cannot cover the entire liquid surface after the device is tilted, the laser light emitted by the annular laser light strip 10 can still irradiate the entire floating thin sheet 12. Its reflected light is received by the multi-point laser sensor 11, and after being processed by the signal converter 9, the height difference h between any two points in any direction of the diameter endpoints passing through the center of the circle is obtained; since the diameter is a fixed value x, the value of tanθ = h / x can be obtained by using a right triangle, and thus the tilt angle θ can be obtained and output through the cable 14, and the display 19 displays the tilt degree in real time.

[0045] As Figure 5 and Figure 7 shown, ultrasonic transmitters 4 and receiving probes 3 are arranged at intervals along the height direction of the steel sheet pile 1, that is, the ultrasonic transmitters 4 and the receiving probes 3 are arranged in groups; wherein, a group of ultrasonic transmitters 4 and receiving probes 3 are arranged at each measuring point on the inner wall of the steel sheet pile 1. The ultrasonic transmitter 4 is spherical, and the ultrasonic transmitter 4 is located at the center of the receiving probe 3. The adjacent receiving probes 3 are connected by a transmitting and receiving cable 16, and the transmitting and receiving cable 16 connecting the top receiving probe 3 is connected to the single-chip microcomputer 17, and the single-chip microcomputer 17 is connected to the display 19 through a display cable 18.

[0046] As Figure 4 and Figure 7As shown in the figure, a metal sheet 5 is provided in the protective tube 2. The metal sheet 5 is located at the middle position of the protective tube 2 and extends along the length direction of the protective tube 2. The metal sheet 5 is parallel to the plane where the ultrasonic transmitter 4 and the receiving probe 3 are installed on the steel sheet pile 1. The bottom end of the metal sheet 5 is close to the end of the protective tube 2, and the top end is rotatably connected to the top of the protective tube 2 through a rotating shaft 6. The metal sheet 5 is rectangular, and its length covers the arrangement area of the ultrasonic transmitter 4 and the receiving probe 3. The metal sheet 5, the ultrasonic transmitter 4 and the receiving probe 3 form a curvature measuring device.

[0047] The curvature measuring device can only provide the deformation of the steel sheet pile relative to itself, and cannot know the inclination and deformation of the steel sheet pile relative to the vertical direction. Therefore, the angle measuring device provides an initial angle for the curvature measuring device so that the obtained inclination curve of the steel sheet pile is relative to the vertical direction, which is more accurate and also corresponds to the maximum inclination angle of the alarm device.

[0048] In this embodiment, the metal sheet 5 is made of a steel sheet.

[0049] Since the metal sheet 5 is rotatably connected to the protective tube 2, the metal sheet 5 can rotate freely along the rotating shaft 6. When the steel sheet pile 1 is inclined, the metal sheet 5 always remains vertically downward. The ultrasonic transmitter 4 and the receiving probe 3 are arranged at the measuring points on the steel sheet pile 1 according to the actual situation, and the horizontal displacement relative to the metal sheet 5 at the measuring points can be measured in real time, transmitted through the transmitting and receiving cable 16, and then converted into the inclination angle of each point of the steel sheet pile 1 through the calculation of the single-chip microcomputer 17, and the inclination curve of the bending deformation of the steel sheet pile 1 is displayed after being processed in the display 19.

[0050] As Figure 6 and Figure 9 shown in the figure, an alarm device is installed at the bottom of the protective tube 2 to give an alarm when the allowable maximum inclination angle is reached. After the alarm, the steel sheet pile can be adjusted in time, pulled out or corrected. The alarm device includes insulating sheets 20. One insulating sheet 20 is fixed to the inner wall of the steel sheet pile 1, and the other insulating sheet 20 is fixed to the inner wall of the protective tube 2. The two insulating sheets 20 are arranged opposite to each other. The insulating sheet 20 has a certain thickness, for example, a PVC sheet with a certain thickness is used.

[0051] The transmitting and receiving cable 16 connected to the end receiving probe 3 is divided into two strands and pasted on both sides of the insulating sheet 20 on the steel sheet pile 1, and extends all the way to the insulating sheet 20 on the side of the protective tube 2. The transmitting and receiving cable 16 is in an open circuit state on the two insulating sheets 20.

[0052] The radius of the protective tube 2 is determined by the maximum inclination angle limit value of the steel sheet pile 1. The maximum inclination angle is set according to the needs of each project; when the maximum inclination angle is reached, the bottom end of the metal sheet 5 will contact the two strands of cables on the insulating sheet 20 to form a circuit, so that a warning signal will appear on the display 19, which is convenient to make a timely response.

[0053] In this embodiment, the time difference from laser emission to reflection is utilized, and the annular laser light strip 10 is fixed. No matter in what situation, the liquid surface will remain absolutely horizontal. The lowest and highest positions of the liquid surface can be measured in real time, and the height difference between the two can be accurately and quickly determined to calculate the tilt angle, and the tilt angle in which direction is the largest can be determined according to the position.

[0054] In this embodiment, the medium for ultrasonic wave propagation is air, and the transmission medium is relatively stable. The outer protective pipe is made of PPR material, with strong compressive capacity, good toughness and sealing performance. Therefore, the device can be applied to various soil bodies; the ultrasonic transmitter 4 is pasted on the steel sheet pile, ensuring that its deformation is consistent with that of the steel sheet pile 1, with stable position and no need for adjustment at any time. The distance between monitoring points is set reasonably, and the surrounding components will not affect the shortest reception time of ultrasonic waves, and the relative displacements of each point can be monitored simultaneously, reflecting the overall deformation of the steel sheet pile in real time.

[0055] Embodiment 2:

[0056] This embodiment provides an implementation method for a full-recovery foundation pit retaining structure wall deformation measurement device, adopting the measurement system described in Embodiment 1, including:

[0057] When the steel sheet pile 1 tilts, the angle measuring device 8 will also tilt together. The floating thin sheet 12 will always remain horizontal along with the liquid medium 13. After being powered on, the annular laser light strip 10 above the liquid surface will emit a circle of laser light towards the liquid surface. Since the diameter of the annular laser light strip 10 is smaller than that of the floating thin sheet 12; although the floating thin sheet 12 cannot cover the entire liquid surface after the device tilts, the laser light emitted by the annular laser light strip 10 can still be completely irradiated onto the floating thin sheet 12, and its reflected light is received by the multi-point laser sensor 11. Through the processing of the signal converter 9, the height difference h between any two points in any one direction of the diameter endpoints passing through the center of the circle is obtained.

[0058] Since the diameter is a fixed value x, the value of tanθ = h / x is obtained by using a right triangle, and thus the tilt angle θ can be obtained and output through the cable 14, and the display 19 displays the tilt degree in real time.

[0059] An ultrasonic transmitter 4 and a receiving probe 3 are pasted on each measuring point of the steel sheet pile 1 and are connected through a transmitting and receiving cable 16. During the excavation of the foundation pit, the rock and soil mass deforms, and the steel sheet pile 1 will also undergo a certain deformation. However, the metal sheet 5 in the center of the protection tube 2 will rotate around the rotating shaft 6 and always maintain a vertically downward direction. After being powered on, the ultrasonic transmitter 4 will emit ultrasonic waves around it, and the receiving probe 3 will receive the ultrasonic waves that are reflected back the fastest (since the distance between the measuring points is much larger than the radius of the protection tube 2, the ultrasonic waves emitted between the measuring points will not affect each other), that is, the ultrasonic waves in the horizontal direction. The horizontal displacement of each measuring point relative to the metal sheet 5 can be obtained from the time difference of the ultrasonic wave emission and return, and is transmitted to the single-chip microcomputer 17 through the transmitting and receiving cable 16 to calculate the inclination angle between the measuring points, and is processed through the display cable 18, and finally the real-time bending deformation curve of the steel sheet pile 1 is displayed on the display 19.

[0060] When the inclination angle of the steel sheet pile 1 reaches the maximum allowable inclination angle, the bottom end of the metal sheet 5 contacts the two cables on the insulating sheet 20, causing the cables to be connected, so that a warning signal appears on the display 19.

[0061] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A full-recovery foundation pit retaining structure wall deformation measurement device, characterized in that, It includes steel sheet piles and a protective pipe fixed to the inner wall of the steel sheet piles. A goniometric device is installed at the top of the protective pipe, and a drill bit is connected to the bottom; ultrasonic transmitters and receiving probes are arranged in groups at each measuring point of the steel sheet piles. A metal sheet is rotatably connected inside the protective pipe to keep it in a vertical state and reflect ultrasonic waves; the metal sheet extends along the length direction of the protective pipe. The goniometric device includes a goniometric cylinder filled with a liquid medium, and a suspended thin sheet is arranged in the liquid medium; an annular laser light strip is fixed on the upper side of the goniometric cylinder, and a multi-point laser sensor is arranged inside the annular laser light strip. An alarm device is installed at the bottom of the protective pipe. The alarm device includes insulating sheets oppositely arranged on the inner walls of the steel sheet piles and the protective pipe. The transmitting and receiving cables connected to the ultrasonic transmitters and receiving probes are pasted on both sides of the insulating sheets in two strands; when the inclination angle of the steel sheet piles reaches the maximum allowable inclination angle, the bottom end of the metal sheet contacts the two circuits on the surface of the insulating sheet.

2. The deformation measurement device for the wall body of a fully recycled foundation pit retaining structure according to claim 1, wherein A signal converter is arranged above the annular laser light strip, and the signal converter is used to process the reflected light received by the multi-point laser sensor.

3. The full-recovery foundation pit retaining structure wall deformation measurement device according to claim 2, characterized in that, The signal converter is connected to a display through a cable.

4. A full-recovery foundation pit retaining structure wall deformation measurement device according to claim 1, characterized in that, The liquid medium is water; the protective pipe is made of PPR material.

5. The implementation method of a fully recoverable foundation pit retaining structure wall deformation measurement device according to any one of claims 1-4, characterized in that, It includes: When the steel sheet piles are inclined, the goniometric device is inclined together. The suspended thin sheet in it always keeps the liquid level horizontal with the liquid medium. After being powered on, the annular laser light strip above the liquid level emits a circle of laser light to the liquid level, and its reflected light is received by the multi-point laser sensor. Through the processing of the signal converter, the height difference between two points in any direction of the diameter endpoints passing through the center of the circle is obtained, and thus the inclination angle is obtained. When the steel sheet piles are inclined, the metal sheet in the protective pipe will rotate around the rotating shaft and always keep vertically downward. After being powered on, the ultrasonic transmitter emits ultrasonic waves around it, and the receiving probe receives the ultrasonic waves reflected back the fastest. The horizontal displacement of each measuring point relative to the metal sheet is obtained from the time difference between the ultrasonic wave emission and return; it is transmitted to the single-chip microcomputer through the transmitting and receiving cable to calculate the inclination angle between each measuring point. After processing, the real-time bending deformation curve of the steel sheet piles is displayed on the display. When the inclination angle of the steel sheet piles reaches the maximum allowable inclination angle, the bottom end of the metal sheet contacts the two circuits on the insulating sheet, making the circuit connected, and thus a warning signal appears on the display.

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