A device and method for measuring bottom surface height of foundation pit construction

Abstract

The invention relates to the technical field of foundation pit height measurement, and discloses a foundation pit construction bottom surface height measurement device and method, wherein the measurement device comprises a bracket, a plurality of adjustable support legs respectively connected to the four corners of the lower end of the bracket, a traction mechanism and a laser transmitter connected to the bracket, an elastic force measuring mechanism connected to the output end of the traction mechanism, an angle deflection detection mechanism connected to one end of the elastic force measuring mechanism, a gravity block connected to the other end of the angle deflection detection mechanism, and a laser receiver connected to the gravity block, wherein the laser receiver is matched with the laser transmitter; the invention adopts the traction mechanism to hoist the gravity block into the foundation pit, and performs automatic data collection on the state of the gravity block at the bottom of the foundation pit through the elastic force measuring mechanism and the angle deflection detection mechanism, and the measurement accuracy is not affected by obstacles at the bottom of the foundation pit, and the accuracy is high and the measurement rate is high.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit height measurement, and more specifically, to a device and method for measuring the bottom surface height of a foundation pit construction. Background Art

[0002] The foundation pit is a soil pit excavated at the foundation design location according to the base elevation and foundation plane dimensions. During the construction of the foundation pit, the height of the foundation pit needs to be measured.

[0003] Due to the uneven bottom of the foundation pit, the use of laser rangefinders to measure the height of the foundation pit often results in inaccuracy or failure to collect data. The manual deployment of laser receiving components at the bottom of the foundation pit is rather cumbersome, and some foundation pits are small and difficult to manually enter for deployment, resulting in inaccurate and cumbersome foundation pit measurement, which reduces the construction rate. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for measuring the bottom height of a foundation pit in order to solve the above-mentioned problem.

[0005] The present invention provides a bottom surface height measuring device for foundation pit construction, comprising a bracket, adjustable supporting legs respectively connected to the four corners of the lower end of the bracket, a traction mechanism and a laser transmitter connected to the bracket, an elastic force measuring mechanism connected to the output end of the traction mechanism, an angle deflection detection mechanism connected to one end of the elastic force measuring mechanism, a gravity block connected to the other end of the angle deflection detection mechanism, and a laser receiver connected to the gravity block, wherein the laser receiver is matched with the laser transmitter;

[0006] The traction mechanism includes a winding assembly, a traction rope connected to the winding assembly, a power assembly connected to the bracket, and an output torque adjustment assembly, wherein the output shaft end of the power assembly is connected to one end of the winding assembly through the output torque adjustment assembly, and the output torque adjustment assembly is used to adjust the torque value received by the winding assembly;

[0007] The elastic force measuring mechanism includes an elastic telescopic component and a tension sensor arranged in the elastic telescopic component. The two ends of the elastic telescopic component are respectively fixedly connected to the traction rope and the angle deflection detection mechanism. The tension sensor is used to detect the tension value applied by the elastic telescopic component to the traction rope.

[0008] The angle deflection detection mechanism is used to detect the angle value between the gravity block and the horizontal plane when the gravity block is deflected.

[0009] As a further optimization scheme of the present invention, the winding assembly includes a winding reel movably connected to the bracket, a wire rack and a first angle sensor, and a first damping disk connected to the end of the winding reel shaft. The other end of the traction rope is connected to the winding reel, and the first angle sensor is mounted on the outside of the winding reel shaft for detecting the rotation angle of the winding reel.

[0010] As a further optimization scheme of the present invention, the power assembly includes a fixed plate connected to the bracket, a first motor connected to the fixed plate, a hollow sleeve sleeved on the output shaft of the first motor, and a second damping disk connected to one end of the hollow sleeve, and the second damping disk is coaxially arranged and in contact with the first damping disk.

[0011] As a further optimization solution of the present invention, a square slide groove is provided in the hollow sleeve, and the output shaft end of the first motor is connected to a first square slider, and the first square slider is matched with the square slide groove.

[0012] As a further optimization scheme of the present invention, the torque adjustment assembly includes a second motor and a limit rod connected to a fixed plate, a screw connected to the output shaft end of the second motor, a pressure plate slidably connected to the limit rod, a first spring connected to the pressure plate, and a pressure ring connected to the other end of the first spring, the pressure ring is movably connected to the second damping disk, the pressure plate is provided with a through hole for a hollow sleeve to pass through, and the screw is threadedly connected to the pressure plate.

[0013] As a further optimization scheme of the present invention, the elastic telescopic component includes a sleeve rod, a second square slider slidably connected to the inner wall of the sleeve rod, a second spring connected to one end of the second square slider, and a first connecting rod connected to the other end of the second square slider. The tension sensor is fixedly connected to the inner wall of one end of the sleeve rod, the second spring is connected to the tension sensor, and the sleeve rod is fixedly connected to the traction rope.

[0014] As a further optimization scheme of the present invention, the angle deflection detection mechanism includes a cross universal joint, a second angle sensor and a third angle sensor connected to the cross universal joint, and a second connecting rod connected to the other end of the cross universal joint, the second angle sensor is arranged along the X-axis, the third angle sensor is arranged along the Y-axis, the second angle sensor is used to detect the rotation angle of the shaft arranged along the X-axis of the cross universal joint, and the third angle sensor is used to detect the rotation angle of the shaft arranged along the Y-axis of the cross universal joint.

[0015] As a further optimization solution of the present invention, a counterweight block is provided on the gravity block, the weight of the counterweight block is equal to the weight of the laser receiver, and the counterweight block and the laser receiver are symmetrically arranged.

[0016] The present invention also provides a method for measuring the bottom surface height of a foundation pit construction, using the above-mentioned bottom surface height measuring device for foundation pit construction, comprising the following steps:

[0017] Set up the bracket above the foundation pit and adjust the adjustable support legs to make the bracket in a horizontal state;

[0018] The torque applied to the winding assembly is adjusted by the torque adjusting assembly, so that the gravity block pulls the angle deflection detection mechanism, the elastic force measuring mechanism and the traction rope to descend at a stable rate under the action of its own gravity until the tension value measured by the tension sensor in the elastic force measuring mechanism reaches the set value, and it is determined that the bottom of the gravity block contacts the bottom of the foundation pit;

[0019] When the tension value measured by the tension sensor reaches the set value, the angle deflection detection mechanism detects the deflection angle of the gravity block when it contacts the bottom of the foundation pit, and calculates the actual depth of the foundation pit through the deflection angle.

[0020] The beneficial effects of the present invention are as follows: the present invention adopts a traction mechanism to hoist the gravity block into the foundation pit, and the laser receiver can be arranged on the bottom of the foundation pit without the need for human entry into the foundation pit. At the same time, an elastic force measuring mechanism is provided to ensure that when the gravity block reaches the bottom of the foundation pit, its traction rope can be in a straightened state, and the elastic force measuring mechanism can be used to determine whether the gravity block has reached the bottom of the foundation pit, thereby ensuring the accuracy of the measurement; the present invention also uses an angle deflection detection mechanism to automatically collect data on the state of the gravity block at the bottom of the foundation pit, and the measurement accuracy is not affected by obstacles at the bottom of the foundation pit, and the accuracy is high and the measurement rate is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 It is a structural schematic diagram of the traction mechanism of the present invention;

[0023] Figure 3 The present invention Figure 1 Magnified view at A in the middle;

[0024] Figure 4 The present invention Figure 1 Magnified view at B in the middle;

[0025] Figure 5 The present invention Figure 2 Enlarged view at center C;

[0026] Figure 6 It is a schematic diagram of the state when the gravity block of the present invention is in a tilted and stable state.

[0027] In the figure: 1, bracket; 2, adjustable support leg; 3, traction mechanism; 301, winding drum; 302, wire rack; 303, traction rope; 304, first angle sensor; 305, first damping disc; 306, fixing plate; 307, first motor; 308, hollow sleeve; 309, first square slider; 310, second damping disc; 311, second motor; 312, limit rod; 313, screw rod; 314, pressure plate; 3 15. First spring; 4. Elastic force measuring mechanism; 401. Sleeve rod; 402. Tension sensor; 403. Second square slider; 404. Second spring; 405. First connecting rod; 5. Angle deflection detection mechanism; 501. Cross universal joint; 502. Second angle sensor; 503. Third angle sensor; 504. Second connecting rod; 6. Gravity block; 601. Laser receiver; 602. Counterweight block; 7. Laser transmitter. DETAILED DESCRIPTION

[0028] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only intended to enable those skilled in the art to better understand and implement the subject matter described herein. In addition, the features described relative to some examples may also be combined in other examples.

[0029] like Figure 1-Figure 5 As shown, a foundation pit construction bottom surface height measuring device comprises a bracket 1, a plurality of adjustable supporting legs 2 respectively connected to the four corners of the lower end of the bracket 1, a traction mechanism 3 and a laser transmitter 7 connected to the bracket 1, an elastic force measuring mechanism 4 connected to the output end of the traction mechanism 3, an angle deflection detection mechanism 5 connected to one end of the elastic force measuring mechanism 4, a gravity block 6 connected to the other end of the angle deflection detection mechanism 5, and a laser receiver 601 connected to the gravity block 6, wherein the laser receiver 601 is matched with the laser transmitter 7;

[0030] The traction mechanism 3 includes a winding assembly, a traction rope 303 connected to the winding assembly, a power assembly connected to the bracket 1, and an output torque adjustment assembly. The output shaft end of the power assembly is connected to one end of the winding assembly through the output torque adjustment assembly. The output torque adjustment assembly is used to adjust the torque value received by the winding assembly.

[0031] The elastic force measuring mechanism 4 includes an elastic telescopic component and a tension sensor 402 disposed in the elastic telescopic component. The two ends of the elastic telescopic component are fixedly connected to the traction rope 303 and the angle deflection detection mechanism 5 respectively. The tension sensor 402 is used to detect the tension value applied by the elastic telescopic component to the traction rope 303.

[0032] The angle deflection detection mechanism 5 is used to detect the angle value between the gravity block 6 and the horizontal plane when the gravity block 6 is deflected.

[0033] It should be noted that when measuring the height of the foundation pit, the bracket 1 is first erected above the foundation pit, and the adjustable supporting legs 2 are adjusted so that the bracket 1 is in a horizontal state; the laser transmitter 7 is located at the mouth of the foundation pit.

[0034] The torque applied to the winding assembly is adjusted by the torque adjustment assembly, so that the gravity block 6 pulls the angle deflection detection mechanism 5, the elastic force measuring mechanism 4 and the traction rope 303 downward at a stable rate under the action of its own gravity. At this time, the elastic telescopic assembly in the elastic force measuring mechanism 4 is in its longest state, and the tension value measured by the tension sensor 402 arranged inside it is also the maximum value. Until the tension value measured by the tension sensor 402 in the elastic force measuring mechanism 4 reaches the set value, it is determined that the bottom of the gravity block 6 contacts the bottom of the foundation pit, that is, when the gravity block 6 is stationary at the bottom of the foundation pit, the elastic telescopic assembly is no longer affected by gravity, but the elastic force generated when it is in the longest state can still pull the traction rope 303 downward, until the elastic force generated by it can no longer pull the traction rope 303, it is in a stable state, and the traction rope 303 is also in a stable and taut state at this time, which can effectively increase the accuracy of height measurement. Specifically, ensuring that the traction rope 303 is in a taut state can effectively improve the accuracy of the angle data measured by the angle deflection detection mechanism 5.

[0035] When the tension value measured by the tension sensor 402 reaches the set value, if the angle deflection detection mechanism 5 detects the deflection angle of the gravity block 6 when it contacts the bottom of the foundation pit, and calculates the actual depth of the foundation pit through the deflection angle, specifically, the deflection angle of the gravity block 6 can be measured through the Pythagorean theorem, thereby obtaining the actual position data of the bottom of the foundation pit.

[0036] Among them, the winding assembly includes a winding reel 301 movably connected to the bracket 1, a wire rack 302 and a first angle sensor 304, and a first damping disk 305 connected to the shaft end of the winding reel 301. The other end of the traction rope 303 is connected to the winding reel 301. The first angle sensor 304 is mounted on the outside of the shaft of the winding reel 301 for detecting the rotation angle of the winding reel 301.

[0037] It should be noted that when the winding assembly rotates, it is divided into two states. The first state is the state of releasing the traction rope 303, and the other state is the state of retrieving the traction rope 303 and winding it around the winding drum 301. During the rotation process, the rotation angle value of the winding drum 301 is obtained through the first angle sensor 304, so that the actual length of the traction rope 303 released can be obtained. When the gravity block 6 has no angular deflection, the data is compared with the data measured by the laser transmitter 7 and the laser receiver 601, so as to reduce the errors caused by the environmental influences on the data measured by the laser transmitter 7 and the laser receiver 601, such as the influence of dust in the foundation pit on the laser route.

[0038] Among them, the power assembly includes a fixed plate 306 connected to the bracket 1, a first motor 307 connected to the fixed plate 306, a hollow sleeve 308 sleeved on the output shaft of the first motor 307, and a second damping disk 310 connected to one end of the hollow sleeve 308. The second damping disk 310 is coaxially arranged with the first damping disk 305 and in contact with each other.

[0039] A square slide groove is arranged in the hollow sleeve 308 , and the output shaft end of the first motor 307 is connected with a first square slider 309 , and the first square slider 309 is matched with the square slide groove.

[0040] It should be noted that, as mentioned above, when the traction rope 303 is recovered, the torque adjustment component is used for adjustment so that the friction torque generated between the second damping disk 310 and the first damping disk 305 is increased, which can overcome the gravity of the gravity block 6, so that when the first motor 307 drives the hollow sleeve 308 and the second damping disk 310 to rotate, the first damping disk 305 and the winding drum 301 are driven to rotate, so that the traction rope 303 is rewound around the winding drum 301, thereby realizing the recovery of the traction rope 303 and the gravity block 6.

[0041] Among them, the torque adjustment component includes a second motor 311 and a limiting rod 312 connected to the fixed plate 306, a screw 313 connected to the output shaft end of the second motor 311, a pressure plate 314 slidably connected to the limiting rod 312, a first spring 315 connected to the pressure plate 314 and a pressure ring connected to the other end of the first spring 315, the pressure ring is movably connected to the second damping disk 310, the pressure plate 314 is provided with a through hole for the hollow sleeve 308 to pass through, and the screw 313 is threadedly connected to the pressure plate 314.

[0042] It should be noted that, as mentioned above, when the friction torque between the first damping disk 305 and the second damping disk 310 is adjusted by the torque adjustment component, the screw 313 is driven to rotate by the second motor 311. When the screw 313 rotates, the pressure plate 314 is driven to move toward or away from the position of the second damping disk 310, and the compression amount of the first spring 315 is adjusted, so that the pressure value applied by the first spring 315 on the second damping disk 310 changes, thereby changing the friction torque generated between the second damping disk 310 and the first damping disk 305.

[0043] Among them, the elastic telescopic component includes a sleeve rod 401, a second square slider 403 slidably connected to the inner wall of the sleeve rod 401, a second spring 404 connected to one end of the second square slider 403, and a first connecting rod 405 connected to the other end of the second square slider 403, the tension sensor 402 is fixedly connected to the inner wall of one end of the sleeve rod 401, the second spring 404 is connected to the tension sensor 402, and the sleeve rod 401 is fixedly connected to the traction rope 303.

[0044] It should be noted that, as mentioned above, in order to always ensure that the traction rope 303 is in a taut state and obtain the signal that the gravity block 6 is in contact with the bottom of the foundation pit, an elastic telescopic component is added between the traction rope 303 and the angle deflection detection mechanism 5. During the downward movement of the gravity block 6, the total gravity of the gravity block 6 is much greater than the elastic force of the second spring 404. The second spring 404 is stretched and is in its longest state. When the gravity block 6 is in contact with the bottom of the foundation pit, the gravity of the gravity block 6 is borne by the bottom of the foundation pit, so that the first connecting rod 405 no longer applies tension to the second spring 404. The second spring 404 is reset and shortened until the tension it applies to the traction rope 303 is balanced with the torque on the winding drum 301, and is in a stable state. At this time, the traction rope 303 is still in a taut state, and the extended length is known. The deformation distance of the second spring 404 is also known. The angle detection of the angle deflection detection mechanism 5 can be used to obtain the deflection angle of the gravity block 6, and the deflected height of the bottom of the gravity block 6 can be calculated. The height is added to the height measured by the laser rangefinder when the gravity block 6 is not deflected, and the actual bottom position of the foundation pit can be obtained, thereby accurately knowing the height of the foundation pit.

[0045] Among them, the angle deflection detection mechanism 5 includes a cross universal joint 501, a second angle sensor 502 and a third angle sensor 503 connected to the cross universal joint 501, and a second connecting rod 504 connected to the other end of the cross universal joint 501. The second angle sensor 502 is arranged along the X-axis, and the third angle sensor 503 is arranged along the Y-axis. The second angle sensor 502 is used to detect the rotation angle of the shaft of the cross universal joint 501 arranged along the X-axis, and the third angle sensor 503 is used to detect the rotation angle of the shaft of the cross universal joint 501 arranged along the Y-axis.

[0046] It should be noted that, as the weight block 6 deflects, the second connecting rod 504 connected to the weight block 6 deflects at an angle, thereby driving the cross universal joint 501 to deflect and rotate. Since the traction rope 303 is in a taut state, when the weight block 6 is in a stable tilted state, Figure 6As shown, at this time, the specific bending angle of the cross universal joint 501 can be obtained through the second angle sensor 502 and the third angle sensor 503. After calculation by the Pythagorean theorem, the deflection angle value between the gravity block 6 and the horizontal plane can be obtained, thereby obtaining the height data of the downward movement of the corner that is deflected and in contact with the bottom of the foundation pit, thereby accurately knowing the height of the foundation pit; if there is no deflection, the height of the foundation pit is obtained by directly receiving data through the laser receiver 601 located at the mouth of the foundation pit. The calculation process of the foundation pit depth when the gravity block 6 of the present invention is deflected is as follows: because the traction rope 303 is always in a taut state, the part where the traction rope 303 and the cross universal joint 501 are connected is always vertical and coaxial, and the angle change detected by the second angle sensor 502 and the third angle sensor 503, that is, the angle of deflection of the part where the cross universal joint 501 and the gravity block 6 are connected, because the cross universal joint 501 and the gravity block 6 are always vertically connected, therefore, the measured angle deflection data is the degree of inclination between the gravity block 6 and the horizontal plane, that is, Figure 6 The angle a in the figure is , and because the size of the gravity block 6 is known, the length of the gravity block 6 can be obtained. By using the Pythagorean theorem, the downward displacement height of the bottom of one side of the gravity block 6 can be calculated, that is, Figure 6 The h value in the figure is used. Before the gravity block 6 tilts, the laser transmitter 7 and the laser receiver 601 can measure the height distance from the foundation pit opening when the gravity block 6 just touches the obstacle. By adding the h value calculated after the tilt, the actual height data of the foundation pit can be accurately obtained.

[0047] Among them, a counterweight block 602 is provided on the gravity block 6, the weight of the counterweight block 602 is equal to the weight of the laser receiver 601, and the counterweight block 602 and the laser receiver 601 are symmetrically arranged.

[0048] It should be noted that the counterweight block 602 can keep the gravity block 6 in a stable and balanced state without being affected by external forces.

[0049] The present embodiment is described above, but the present embodiment is not limited to the above-mentioned specific implementation manner. The above-mentioned specific implementation manner is merely illustrative and not restrictive. Under the guidance of the present embodiment, ordinary technicians in this field can also make many forms, which are all within the protection of the present embodiment.

Claims

1. A device for measuring the bottom height of a foundation pit, characterized in that: The invention comprises a bracket (1), adjustable supporting legs (2) respectively connected to the four corners of the lower end of the bracket (1), a traction mechanism (3) and a laser transmitter (7) connected to the bracket (1), an elastic force measuring mechanism (4) connected to the output end of the traction mechanism (3), an angle deflection detection mechanism (5) connected to one end of the elastic force measuring mechanism (4), a gravity block (6) connected to the other end of the angle deflection detection mechanism (5), and a laser receiver (601) connected to the gravity block (6), wherein the laser receiver (601) is matched with the laser transmitter (7); The traction mechanism (3) comprises a winding assembly, a traction rope (303) connected to the winding assembly, a power assembly connected to the bracket (1), and an output torque adjustment assembly, wherein the output shaft end of the power assembly is connected to one end of the winding assembly via the output torque adjustment assembly, and the output torque adjustment assembly is used to adjust the torque value received by the winding assembly; The elastic force measuring mechanism (4) comprises an elastic telescopic component and a tension sensor (402) disposed in the elastic telescopic component, the two ends of the elastic telescopic component being fixedly connected to the traction rope (303) and the angle deflection detection mechanism (5) respectively, and the tension sensor (402) being used to detect the tension value applied by the elastic telescopic component to the traction rope (303); The winding assembly comprises a winding drum (301) movably connected to the bracket (1), a wire frame (302) and a first angle sensor (304), and a first damping plate (305) connected to the shaft end of the winding drum (301); the other end of the traction rope (303) is connected to the winding drum (301); the first angle sensor (304) is sleeved on the outside of the shaft of the winding drum (301) and is used to detect the rotation angle of the winding drum (301); The elastic telescopic component comprises a sleeve rod (401), a second square slider (403) slidably connected to the inner wall of the sleeve rod (401), a second spring (404) connected to one end of the second square slider (403), and a first connecting rod (405) connected to the other end of the second square slider (403); the tension sensor (402) is fixedly connected to the inner wall of one end of the sleeve rod (401); the second spring (404) is connected to the tension sensor (402); the first connecting rod (405) is connected to the angle deflection detection mechanism (5); and the sleeve rod (401) is fixedly connected to the traction rope (303); When the tension value measured by the tension sensor (402) reaches a set value, the tension applied by the gravity block (6) to the traction rope (303) and the torque applied to the winding drum (301) reach a balance, and the traction rope (303) is in a taut state; The angle deflection detection mechanism (5) is used to detect the value of the angle between the gravity block (6) and the horizontal plane when the gravity block (6) is deflected.

2. A foundation pit construction bottom surface height measuring device according to claim 1, characterized in that: The power assembly comprises a fixing plate (306) connected to the bracket (1), a first motor (307) connected to the fixing plate (306), a hollow sleeve (308) sleeved on the output shaft of the first motor (307), and a second damping disc (310) connected to one end of the hollow sleeve (308), wherein the second damping disc (310) is coaxially arranged with and in contact with the first damping disc (305).

3. A foundation pit construction bottom surface height measuring device according to claim 2, characterized in that: A square slide groove is provided in the hollow sleeve (308); the output shaft end of the first motor (307) is connected to a first square slider (309); the first square slider (309) is matched with the square slide groove.

4. A foundation pit construction bottom surface height measuring device according to claim 3, characterized in that: The torque adjustment assembly comprises a second motor (311) and a limit rod (312) connected to a fixing plate (306), a screw rod (313) connected to an output shaft end of the second motor (311), a pressure plate (314) slidably connected to the limit rod (312), a first spring (315) connected to the pressure plate (314), and a pressure ring connected to the other end of the first spring (315), the pressure ring being movably connected to the second damping disk (310), the pressure plate (314) being provided with a through hole for the hollow sleeve (308) to pass through, and the screw rod (313) being threadedly connected to the pressure plate (314).

5. A foundation pit construction bottom surface height measuring device according to claim 4, characterized in that: The angle deflection detection mechanism (5) comprises a cross universal joint (501), a second angle sensor (502) and a third angle sensor (503) connected to the cross universal joint (501), and a second connecting rod (504) connected to the other end of the cross universal joint (501); one end of the cross universal joint (501) is connected to the first connecting rod (405); the second angle sensor (502) is arranged along the X-axis, and the third angle sensor (503) is arranged along the Y-axis; the second angle sensor (502) is used to detect the rotation angle of the shaft of the cross universal joint (501) arranged along the X-axis, and the third angle sensor (503) is used to detect the rotation angle of the shaft of the cross universal joint (501) arranged along the Y-axis.

6. A foundation pit construction bottom surface height measuring device according to claim 5, characterized in that: A counterweight block (602) is provided on the gravity block (6); the weight of the counterweight block (602) is equal to the weight of the laser receiver (601), and the counterweight block (602) and the laser receiver (601) are symmetrically arranged.

7. A method for measuring the bottom height of a foundation pit, characterized in that: The measurement is performed using the foundation pit construction bottom surface height measuring device as described in any one of claims 1 to 6, comprising the following steps: The support (1) is erected above the foundation pit, and the adjustable support legs (2) are adjusted so that the support (1) is in a horizontal state; The torque applied to the winding assembly is adjusted by the torque adjustment assembly, so that the gravity block (6) pulls the angle deflection detection mechanism (5), the elastic force measuring mechanism (4) and the traction rope (303) downward at a stable rate under the action of its own gravity until the tension value measured by the tension sensor (402) in the elastic force measuring mechanism (4) reaches a set value, and it is determined that the bottom of the gravity block (6) contacts the bottom of the foundation pit; When the tension value measured by the tension sensor (402) reaches a set value, the angle deflection detection mechanism (5) detects the angle of deflection of the gravity block (6) when it contacts the bottom of the foundation pit, and calculates the actual depth of the foundation pit through the deflection angle.

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