A device and method for detecting sediment thickness at the bottom of a bored pile hole

Abstract

The present invention relates to the field of underground engineering technology, and specifically discloses a device and method for detecting the thickness of sediment at the bottom of a bored pile hole, including a measuring cake, a limiting tube is arranged at the top of the measuring cake; a measuring rod assembly, the measuring rod assembly includes a measuring needle, the measuring needle is slidably mounted on the inner wall of the limiting tube, the top of the measuring needle, a limiting sleeve is installed at the top of the measuring needle, a support rod is installed at the top of the limiting sleeve, a connecting ring is fixedly installed at the top of the support rod, and the connecting ring is used to connect a wire rope; a limiting box, a plurality of variable diameter square boxes are fixedly installed on the outer walls on both sides of the limiting box facing each other, and a first limiting plate is penetrated and slidably installed between the adjacent side walls of the reducing diameter square box and the limiting box. The present invention has a self-weight downward pressure measuring needle, eliminates the power device, reduces the production cost, has a counterweight control function, has strong adaptability to sediment at the bottom of the pile hole, and improves the stability of the detection device.

Description

Technical Field

[0001] The invention relates to the technical field of underground engineering, and in particular to a device and method for detecting the thickness of sediment at the bottom of a bored pile hole. Background Art

[0002] The sediment at the bottom of the bored pile hole refers to the sediment left by the precipitated or collapsed hole during the drilling and emptying process, which is not carried away by the circulating mud. It is generally coarse particles, and the sediment thickness is the sediment layer height. The existence of sediment greatly affects the compressive bearing capacity of the concrete bored pile, or makes the settlement of the building exceed the design requirements. Therefore, the construction and inspection specifications of bored piles have strict regulations on the thickness of sediment. Generally, the sediment thickness should not exceed 50-200mm, and the inspection accuracy is less than 10mm.

[0003] The hammer method, cone method, and cake and needle method are different. The hammer method uses a measuring rope to put the hammer to the bottom of the hole, and then feel the top of the sediment by hand. Then, according to the hole depth measured during drilling, the depth from the top of the sediment to the hole mouth is subtracted to get the sediment thickness. Its measurement accuracy is limited. The cake and needle method measures the top of the sediment with a cake, and measures the position from the cake to the bottom of the hole with a needle. The sediment thickness is obtained by subtracting the depth of the two. The measured pile hole depth can be tens to hundreds of meters. Since it is measured twice and the distance is measured with a measuring rope, it is affected by the tension of the measuring rope and the cumulative error of the two measurements. The final sediment thickness measurement accuracy is limited, and the measurement time is relatively long.

[0004] At present, there are electromechanical devices that combine the measuring cake and the measuring needle. After the measuring cake reaches the top surface of the sediment, the upper host sends a command to press the measuring needle into the sediment through a power device. Although the pressing depth of the measuring needle, that is, the sediment thickness, is automatically measured, the equipment cost of the power device that presses the measuring needle is relatively high, and the components of the power device are easily affected by vibration and shock, thereby being damaged. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a device and method for detecting the thickness of sediment at the bottom of a bored pile hole, which can solve the problems raised in the above background technology.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A device for detecting the thickness of sediment at the bottom of a bored pile hole, comprising: A measuring cake, wherein a limiting tube is provided at the top of the measuring cake; A measuring rod assembly, the measuring rod assembly comprising a measuring needle, the measuring needle is slidably mounted on the inner wall of the limiting tube, the top of the measuring needle is mounted with a limiting sleeve, the top of the limiting sleeve is mounted with a supporting rod, the top of the supporting rod is fixedly mounted with a connecting ring, and the connecting ring is used to connect a wire rope; A limit box, wherein a plurality of diameter-changing square boxes are fixedly installed on the outer walls on both sides facing each other, a first limit plate is penetrated and slidably installed between the adjacent side walls of the diameter-changing square box and the limit box, a U-shaped frame is fixedly installed on one end of the first limit plate located in the diameter-changing square box, a magnetic block is fixedly installed on the inner wall of the U-shaped frame, a bistable electromagnet is arranged on the inner wall of the diameter-changing square box, a spacing is left between the bistable electromagnet and the magnetic block, two first springs are arranged between one end of the magnetic block close to the bistable electromagnet and the inner wall of the diameter-changing square box, and electric control components are arranged on both sides facing each other of the measuring rod assembly; A support assembly, wherein the support assembly comprises four limit rods, the limit rods are fixedly mounted on the top of the measuring cake, the limit rods are penetrated and slidably connected with the limit box, the top of the limit rods is provided with a circular plate, the outer wall of the limit rods is provided with a damping layer, and an elastic support structure is provided between the bottom end of the limit box and the limit rods; A counterweight block, wherein a plurality of the counterweight blocks are slidably sleeved on the side wall of the support rod, a limiting groove is arranged at the bottom end of the counterweight block, the first limiting plate matches the limiting groove, and the outer diameter of the connecting ring is smaller than the inner diameter of the counterweight block; A limiting assembly, wherein the limiting assembly is used to limit the measuring rod assembly.

[0007] Preferably, a through hole is provided at the bottom end of the measuring cake, and the diameter of the through hole of the measuring cake is the same as the inner diameter of the measuring rod assembly.

[0008] Preferably, the electronic control component includes a battery component, which is fixedly mounted on an outer wall of one side of the limit box, and is electrically connected to the three bistable electromagnets on the same side of the limit box. The battery component housing is provided with a PLC controller, and the PLC controller is used to control the multiple bistable electromagnets on the same side of the limit box.

[0009] Preferably, the elastic support structure includes a support ring, which is fixedly sleeved on the side wall of the limiting rod, and a second spring is installed on the top of the support ring. The second spring is sleeved with the limiting rod, and a sliding ring is installed on the top of the second spring. The top of the sliding ring is fitted with the bottom end of the limiting box.

[0010] Preferably, the limit assembly includes two bases, the base is fixedly mounted on the top of the measuring cake, a support block is fixedly mounted on the top of the base, two rail seats are fixedly mounted on the top of the base, a slider is slidably mounted between the two rail seats, the support block is located at an end of the base away from the measuring rod assembly, a second limit plate is provided on the side of the slider close to the measuring rod assembly, the second limit plate and the measuring needle are slidably engaged, a T-bar is fixedly mounted on the side of the slider close to the support block, the T-bar is penetrated and slidably connected to the slider, and an elastic support assembly is provided between the support block and the slider.

[0011] Preferably, the side wall of the measuring needle is provided with a plurality of clamping grooves distributed in an array, the cross section of the clamping groove of the measuring needle is trapezoidal, the inclined surface of the trapezoidal cross section of the clamping groove of the measuring needle is arranged upward, and the cross section of the second limiting plate is trapezoidal.

[0012] Preferably, the elastic support assembly includes a third spring, the third spring is sleeved on the side wall of the T-bar, and both ends of the third spring are installed with limiting rings, and the limiting rings and the T-bar are arranged in a sliding sleeve manner.

[0013] Preferably, the side wall of the limiting tube is provided with two limiting holes, and the limiting holes match the adjacent second limiting plates.

[0014] A method for detecting the thickness of sediment at the bottom of a bored pile hole comprises the following steps: S1. Before putting the device into the pile hole, place it on a flat ground so that the probe is perpendicular to the measuring cake and the bottom of the probe is flush with the bottom of the measuring cake. According to the nature of the sediment at the bottom of the hole, the number of counterweights is determined. Through the PLC controller, the battery assembly cooperates with the bistable electromagnet to increase the magnetic force on the magnetic block. The first spring is compressed, and the magnetic block, the U-shaped frame and the first limit plate slide synchronously in the variable diameter square box, canceling the limit of the adjacent counterweights and adjusting the number of effective counterweights. S2, lift the connecting ring by the wire rope, put the device into the pile hole, when the measuring cake is located on the surface of the sediment at the bottom of the hole, the measuring cake is supported by the sediment, loosen the wire rope, and the measuring needle passes through the central through hole of the measuring cake and is inserted into the bottom of the hole. At the same time, the measuring needle pushes the second limit plate, drives the slider to slide between the two rail seats, and the third spring is compressed between the slider and the support block; S3. Lift the wire rope again and pull the device out of the pile hole. At the same time, the counterweight block presses against the top wall of the limit box, and the slider is reset under the action of the third spring. The second limit plate is inserted into the clamping groove of the measuring needle to fix the measuring needle. The length of the measuring needle protruding from the bottom of the measuring cake is the sediment thickness.

[0015] Preferably, in S2, when the test cake just contacts the surface of the sediment at the bottom of the hole, the limit box and the four sliding rings slide downward synchronously between the four limit rods, the damping layer on the side wall of the limit rod and the limit box frictionally consume kinetic energy, and the second spring is compressed between the sliding ring and the support ring, which has a vibration-reducing effect on the device and improves the stability of the detection device.

[0016] The beneficial effects of the present invention are: 1. By setting a limit assembly, the beneficial effect that can be obtained is a measuring cake, a limit tube is arranged at the top of the measuring cake, the measuring rod assembly includes a measuring needle, the measuring needle is slidably mounted on the inner wall of the limit tube, the top of the measuring needle, the top of the measuring needle is mounted with a limit sleeve, the top of the limit sleeve is mounted with a support rod, the top of the support rod is fixedly mounted with a connecting ring, and the connecting ring is used to connect a wire rope, the supporting assembly includes four limit rods, the limit rod is fixedly mounted on the top of the measuring cake, the limit rod and the limit box are penetrated and slidably connected, the top of the limit rod is provided with a circular plate, the outer wall of the limit rod is provided with a damping layer, an elastic supporting structure is provided between the bottom end of the limit box and the limit rod, a plurality of the counterweight blocks are slidably sleeved on the side wall of the support rod, a limit groove is provided at the bottom end of the counterweight block, the first limit plate matches the limit groove, the outer diameter of the connecting ring is smaller than the inner diameter of the counterweight block, and the limit assembly is used to limit the measuring rod assembly; Place the device on a flat ground so that the measuring needle is perpendicular to the measuring cake and the bottom end of the measuring needle is flush with the bottom surface of the measuring cake. Lift up the connecting ring through the wire rope and put the device into the pile hole. When the measuring cake is on the sediment surface at the bottom of the hole, the measuring cake is supported by the sediment. Release the wire rope, and the measuring needle passes through the central through hole of the measuring cake and is inserted down to the bottom of the hole. At the same time, the measuring needle pushes the second limit plate, driving the slider to slide between the two rail seats. The third spring is compressed between the slider and the support block. Lift the wire rope again and pull the device out of the pile hole. The length of the measuring needle protruding from the bottom surface of the measuring cake is the sediment thickness. The measuring needle has its own weight-pressed type, which eliminates the need for a power device and reduces production costs.

[0017] 2. By setting the counterweight block, the beneficial effect that can be obtained is that a plurality of diameter-changing square boxes are fixedly installed on the outer walls on both sides facing each other of the limit box, a first limit plate is penetrated and slidably installed between the adjacent side walls of the diameter-changing square box and the limit box, a U-shaped frame is fixedly installed on one end of the first limit plate located in the diameter-changing square box, a magnetic block is fixedly installed on the inner wall of the U-shaped frame, a bistable electromagnet is arranged on the inner wall of the diameter-changing square box, a spacing is left between the bistable electromagnet and the magnetic block, two first springs are arranged between one end of the magnetic block close to the bistable electromagnet and the inner wall of the diameter-changing square box, and electric control components are arranged on both sides facing each other of the measuring rod assembly; According to the properties of the sediment at the bottom of the hole, the number of counterweights is determined. Through the PLC controller, the battery assembly cooperates with the bistable electromagnet to increase the magnetic force on the magnetic block. The first spring is compressed, and the magnetic block, U-shaped frame and the first limit plate slide synchronously in the variable diameter square box, canceling the limit on adjacent counterweights and adjusting the number of effective counterweights. It has the function of counterweight regulation and has strong adaptability to the sediment at the bottom of the pile hole.

[0018] 3. By setting the support assembly and the elastic support structure, the beneficial effect that can be obtained is that the elastic support structure includes a support ring, the support ring is fixedly sleeved on the side wall of the limit rod, a second spring is installed on the top of the support ring, the second spring is sleeved with the limit rod, a sliding ring is installed on the top of the second spring, and the top of the sliding ring is fitted with the bottom end of the limit box; When the test cake just touches the surface of the sediment at the bottom of the hole, the limit box and the four sliding rings slide downward synchronously between the four limit rods. The damping layer on the side wall of the limit rod and the limit box frictionally consume kinetic energy. The second spring is compressed between the sliding ring and the support ring, which has a vibration reduction effect on the device and improves the stability of the detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 The figure is a structural diagram of the installation of the counterweight block and the support rod in the present invention; Figure 3 It is the installation structure diagram of the limit box in the present invention; Figure 4 It is the installation structure diagram of the bistable electromagnet and the variable diameter square box in the present invention; Figure 5 This is a diagram of the installation structure of the first limiting plate and the U-shaped frame in the present invention; Figure 6 It is the installation structure diagram of the elastic support structure in the present invention; Figure 7 This is a diagram of the installation structure of the elastic support assembly in the present invention; Figure 8 It is the installation structure diagram of the T-bar in the present invention.

[0021] Description of reference numerals: In the figure: 1. measuring cake; 11. limiting tube; 12. limiting hole; 2. measuring rod assembly; 21. measuring needle; 22. limiting sleeve; 23. supporting rod; 24. connecting ring; 3. limiting box; 31. reducing square box; 32. first limiting plate; 33. U-shaped frame; 34. magnetic block; 35. bistable electromagnet; 36. first spring; 37. battery assembly; 38. PLC controller; 41. limiting rod; 42. round plate; 43. supporting ring; 44. second spring; 45. sliding ring; 5. counterweight; 51. limiting groove; 6. limiting assembly; 61. base; 62. supporting block; 63. rail seat; 64. sliding block; 65. second limiting plate; 66. stop block; 67. T-bar; 68. third spring; 69. limiting ring. DETAILED DESCRIPTION

[0022] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are clearly and completely described below in combination with the accompanying drawings and preferred embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of the present application, it should be understood that the orientation or position relationship indicated by "inside", "outside", etc. is based on the orientation or position described in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, a specific orientation structure and operation, and therefore cannot be understood as a limitation on the present application.

[0024] Reference Figure 1-Figure 8 , a device and method for detecting the thickness of sediment at the bottom of a bored pile hole disclosed in the present invention, comprising a measuring cake 1, a limiting tube 11 is arranged at the top of the measuring cake 1, two limiting holes 12 are arranged on the side wall of the limiting tube 11, a through hole is arranged at the bottom of the measuring cake 1, and the diameter of the through hole of the measuring cake 1 is the same as the inner diameter of the measuring rod assembly 2; The measuring rod assembly 2 includes a measuring needle 21, which is slidably mounted on the inner wall of the limiting tube 11, and a limiting sleeve 22 is mounted on the top of the measuring needle 21. A support rod 23 is mounted on the top of the limiting sleeve 22, and a connecting ring 24 is fixedly mounted on the top of the support rod 23. The connecting ring 24 is used to connect the wire rope; The limiting box 3 has a plurality of reducing square boxes 31 fixedly installed on the outer walls on both sides of the limiting box 3. A first limiting plate 32 is inserted and slidably installed between the reducing square box 31 and the adjacent side walls of the limiting box 3. A U-shaped frame 33 is fixedly installed on one end of the first limiting plate 32 located in the reducing square box 31. A magnetic block 34 is fixedly installed on the inner wall of the U-shaped frame 33. A bistable electromagnet 35 is arranged on the inner wall of the reducing square box 31. A spacing is left between the bistable electromagnet 35 and the magnetic block 34. The magnetic block 34 is close to the bistable electromagnet. Two first springs 36 are arranged between one end of the magnet 35 and the inner wall of the variable diameter square box 31. The two opposite sides of the measuring rod assembly 2 are provided with electric control components, which include a battery assembly 37. The battery assembly 37 is fixedly mounted on the outer wall of one side of the limit box 3. The battery assembly 37 is electrically connected to the three bistable electromagnets 35 on the same side of the limit box 3. The housing of the battery assembly 37 is provided with a PLC controller 38, which is used to control the multiple bistable electromagnets 35 on the same side of the limit box 3. A support assembly, the support assembly includes four limit rods 41, the limit rods 41 are fixedly installed on the top of the test cake 1, the limit rods 41 and the limit box 3 are penetrated and slidably connected, a circular plate 42 is provided at the top of the limit rod 41, a damping layer is provided on the outer wall of the limit rod 41, an elastic support structure is provided between the bottom end of the limit box 3 and the limit rod 41, and the elastic support structure includes a support ring 43, the support ring 43 is fixedly sleeved on the side wall of the limit rod 41, a second spring 44 is installed on the top of the support ring 43, the second spring 44 is sleeved with the limit rod 41, a sliding ring 45 is installed on the top of the second spring 44, and the top of the sliding ring 45 is fitted with the bottom end of the limit box 3; The counterweight block 5 is slidably sleeved on the side wall of the support rod 23. The outer diameter of the connecting ring 24 is smaller than the inner diameter of the counterweight block 5. A limiting groove 51 is provided at the bottom end of the counterweight block 5. The first limiting plate 32 matches the limiting groove 51. The limit assembly 6 is used to limit the measuring rod assembly 2. The limit assembly 6 includes two bases 61, the base 61 is fixedly installed on the top of the measuring cake 1, and a support block 62 is fixedly installed on the top of the base 61. Two rail seats 63 are fixedly installed on the top of the base 61. A slider 64 is slidably installed between the two rail seats 63. The support block 62 is located at the end of the base 61 away from the measuring rod assembly 2. A second limit plate 65 is arranged on the side of the slider 64 close to the measuring rod assembly 2. The second limit plate 65 is slidably connected with the measuring needle 21. The limit hole 12 matches the adjacent second limit plate 65. The side wall of the measuring needle 21 A plurality of clamping grooves distributed in an array are provided, the cross-section of the clamping groove of the measuring needle 21 is trapezoidal, the inclined surface of the trapezoidal cross-section of the clamping groove of the measuring needle 21 is arranged upward, the cross-section of the second limiting plate 65 is trapezoidal, a T-shaped rod 67 is fixedly installed on the side of the slider 64 close to the support block 62, the T-shaped rod 67 and the slider 64 are penetrated and slidably connected, an elastic support assembly is provided between the support block 62 and the slider 64, the elastic support assembly includes a third spring 68, the third spring 68 is sleeved on the side wall of the T-shaped rod 67, both ends of the third spring 68 are installed with limiting rings 69, the limiting rings 69 and the T-shaped rod 67 are slidably sleeved.

[0025] The present invention discloses a method for detecting the thickness of sediment at the bottom of a bored pile hole, comprising the following steps: S1. Before putting the device into the pile hole, place the device on a flat ground so that the probe 21 is perpendicular to the measuring cake 1, and the bottom end of the probe 21 is flush with the bottom surface of the measuring cake 1. According to the nature of the sediment at the bottom of the hole, the number of counterweights 5 is determined. Through the PLC controller 38, the battery assembly 37 cooperates with the bistable electromagnet 35 to increase the magnetic force on the magnetic block 34, the first spring 36 is compressed, and the magnetic block 34, the U-shaped frame 33 and the first limit plate 32 slide synchronously in the variable diameter square box 31, cancel the limit on the adjacent counterweight 5, and adjust the number of effective counterweights 5; S2, lift up the connecting ring 24 through the wire rope, put the device into the pile hole, when the measuring cake 1 is located on the sediment surface at the bottom of the hole, the measuring cake 1 is supported by the sediment, loosen the wire rope, and the measuring needle 21 passes through the central through hole of the measuring cake 1 and is inserted into the bottom of the hole. At the same time, the measuring needle 21 pushes the second limit plate 65, drives the slider 64 to slide between the two rail seats 63, and the third spring 68 is compressed between the slider 64 and the support block 62; S3. Lift the wire rope again and pull the device out of the pile hole. At the same time, the counterweight block 5 presses against the top wall of the limit box 3, and the slider 64 is reset under the action of the third spring 68. The second limit plate 65 is inserted into the clamping groove of the measuring needle 21 to fix the measuring needle 21. The length of the measuring needle 21 protruding from the bottom surface of the measuring cake 1 is the sediment thickness.

[0026] Preferably, in S2, when the test cake 1 just contacts the surface of the sediment at the bottom of the hole, the limit box 3 and the four sliding rings 45 slide downward synchronously between the four limit rods 41, the damping layer on the side wall of the limit rod 41 and the limit box 3 frictionally consume kinetic energy, and the second spring 44 is compressed between the sliding ring 45 and the support ring 43, which has a vibration-reducing effect on the device and improves the stability of the detection device.

[0027] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A device for detecting the thickness of sediment at the bottom of a bored pile hole, characterized in that: include: A measuring cake (1), wherein a limiting tube (11) is provided at the top of the measuring cake (1); A measuring rod assembly (2), the measuring rod assembly (2) comprising a measuring needle (21), the measuring needle (21) being slidably mounted on the inner wall of the limiting tube (11), the top end of the measuring needle (21) being mounted with a limiting sleeve (22), the top end of the limiting sleeve (22) being mounted with a supporting rod (23), the top end of the supporting rod (23) being fixedly mounted with a connecting ring (24), the connecting ring (24) being used for connecting a steel wire rope; A limit box (3), wherein a plurality of diameter-changing square boxes (31) are fixedly installed on the outer walls on both sides facing each other of the limit box (3), a first limit plate (32) is penetrated and slidably installed between the adjacent side walls of the diameter-changing square box (31) and the limit box (3), a U-shaped frame (33) is fixedly installed on one end of the first limit plate (32) located in the diameter-changing square box (31), a magnetic block (34) is fixedly installed on the inner wall of the U-shaped frame (33), a bistable electromagnet (35) is arranged on the inner wall of the diameter-changing square box (31), a spacing is left between the bistable electromagnet (35) and the magnetic block (34), two first springs (36) are arranged between one end of the magnetic block (34) close to the bistable electromagnet (35) and the inner wall of the diameter-changing square box (31), and electric control components are arranged on both sides facing each other of the measuring rod assembly (2); A support assembly, the support assembly comprising four limit rods (41), the limit rods (41) being fixedly mounted on the top end of the test cake (1), the limit rods (41) being penetrated and slidably connected to the limit box (3), the top end of the limit rods (41) being provided with a circular plate (42), the outer wall of the limit rods (41) being provided with a damping layer, and an elastic support structure being provided between the bottom end of the limit box (3) and the limit rods (41); A counterweight block (5), wherein a plurality of the counterweight blocks (5) are slidably sleeved on the side wall of the support rod (23), a limiting groove (51) is provided at the bottom end of the counterweight block (5), the first limiting plate (32) matches the limiting groove (51), and the outer diameter of the connecting ring (24) is smaller than the inner diameter of the counterweight block (5); A limit assembly (6), the limit assembly (6) is used to limit the position of the measuring rod assembly (2), the limit assembly (6) comprises two bases (61), and the bases (61) are fixedly mounted on the top of the measuring cake (1).

2. A device for detecting the thickness of sediment at the bottom of a bored pile hole according to claim 1, characterized in that: A through hole is provided at the bottom end of the measuring cake (1), and the diameter of the through hole of the measuring cake (1) is the same as the inner diameter of the measuring rod assembly (2).

3. A device for detecting the thickness of sediment at the bottom of a bored pile hole according to claim 1, characterized in that: The electric control component comprises a battery component (37), the battery component (37) is fixedly mounted on an outer wall of one side of the limit box (3), the battery component (37) is electrically connected to three bistable electromagnets (35) on the same side of the limit box (3), and a PLC controller (38) is provided on the housing of the battery component (37), and the PLC controller (38) is used to control the multiple bistable electromagnets (35) on the same side of the limit box (3).

4. A device for detecting the thickness of sediment at the bottom of a bored pile hole according to claim 1, characterized in that: The elastic support structure comprises a support ring (43), the support ring (43) being fixedly sleeved on the side wall of the limiting rod (41), a second spring (44) being mounted on the top end of the support ring (43), the second spring (44) being sleeved with the limiting rod (41), a sliding ring (45) being mounted on the top end of the second spring (44), the top end of the sliding ring (45) being fitted with the bottom end of the limiting box (3).

5. A device for detecting the thickness of sediment at the bottom of a bored pile hole according to claim 1, characterized in that: A support block (62) is fixedly mounted on the top of the base (61), two rail seats (63) are fixedly mounted on the top of the base (61), a slider (64) is slidably mounted between the two rail seats (63), the support block (62) is located at an end of the base (61) away from the measuring rod assembly (2), a second limit plate (65) is arranged on a side of the slider (64) close to the measuring rod assembly (2), the second limit plate (65) is slidably engaged with the measuring needle (21), a T-shaped rod (67) is fixedly mounted on a side of the slider (64) close to the support block (62), the T-shaped rod (67) and the slider (64) are penetrated and slidably connected, and an elastic support assembly is arranged between the support block (62) and the slider (64).

6. A device for detecting the thickness of sediment at the bottom of a bored pile hole according to claim 5, characterized in that: The side wall of the measuring needle (21) is provided with a plurality of clamping grooves distributed in an array, the clamping groove of the measuring needle (21) has a trapezoidal cross section, the inclined surface of the trapezoidal cross section of the clamping groove of the measuring needle (21) is arranged upward, and the cross section of the second limiting plate (65) is arranged in a trapezoidal shape.

7. A device for detecting the thickness of sediment at the bottom of a bored pile hole according to claim 5, characterized in that: The elastic support assembly comprises a third spring (68), the third spring (68) being sleeved on the side wall of the T-shaped rod (67), and limiting rings (69) are installed on both ends of the third spring (68), and the limiting rings (69) are slidably sleeved with the T-shaped rod (67).

8. A device for detecting sediment thickness at the bottom of a bored pile hole according to claim 5, characterized in that: The side wall of the limiting tube (11) is provided with two limiting holes (12), and the limiting holes (12) match the adjacent second limiting plates (65).

9. A method for detecting the thickness of sediment at the bottom of a bored pile hole, applied to the device for detecting the thickness of sediment at the bottom of a bored pile hole as claimed in claim 7, characterized in that: The following steps are involved: S1. Before the device is placed in the pile hole, the device is placed on a flat ground so that the measuring needle (21) is perpendicular to the measuring cake (1) and the bottom end of the measuring needle (21) is flush with the bottom surface of the measuring cake (1). The number of counterweights (5) is determined according to the nature of the sediment at the bottom of the hole. Through the PLC controller (38), the battery assembly (37) cooperates with the bistable electromagnet (35) to increase the magnetic force on the magnetic suction block (34), the first spring (36) is compressed, and the magnetic suction block (34), the U-shaped frame (33) and the first limit plate (32) slide synchronously on the variable diameter square box (31), cancel the limit on the adjacent counterweights (5), and adjust the number of effective counterweights (5); S2, lift the connecting ring (24) by the wire rope, put the device into the pile hole, when the measuring cake (1) is located on the sediment surface at the bottom of the hole, the measuring cake (1) is supported by the sediment, loosen the wire rope, and the measuring needle (21) passes through the central through hole of the measuring cake (1) and is inserted into the bottom of the hole. At the same time, the measuring needle (21) pushes the second limit plate (65), drives the slider (64) to slide between the two rail seats (63), and the third spring (68) is compressed between the slider (64) and the support block (62); S3, lift the wire rope again and pull the device out of the pile hole. At the same time, the counterweight (5) presses against the top wall of the limit box (3), the slider (64) is reset under the action of the third spring (68), the second limit plate (65) is inserted into the clamping groove of the measuring needle (21), the measuring needle (21) is fixed, and the length of the measuring needle (21) protruding from the bottom surface of the measuring cake (1) is measured to be the sediment thickness.

10. A method for detecting sediment thickness at the bottom of a bored pile hole according to claim 9, characterized in that: In S2, when the test cake (1) just contacts the surface of the sediment at the bottom of the hole, the limit box (3) and the four sliding rings (45) slide downwards synchronously between the four limit rods (41), the damping layer on the side wall of the limit rod (41) and the limit box (3) frictionally consume kinetic energy, and the second spring (44) is compressed between the sliding ring (45) and the support ring (43), which has a vibration reduction effect on the device, thereby improving the stability of the detection device.

Images