Device and method for detecting sediment at bottom of cast-in-situ bored pile

Abstract

The invention discloses a cast-in-situ bored pile bottom sediment detection device and a pile bottom sediment detection method.The detection device comprises a shell, a plate and a non-return structure, the lower end of the shell is open, the upper end of the shell is sealed, the shell is hollow, the plate is arranged in the shell and can move in the vertical direction, and a first cavity is formed between the plate and the lower end; the first cavity is used for being inserted into sediment at the bottom of the pile, the non-return structure is arranged above the plate and connected with the plate, and a second cavity is formed between the non-return structure and the upper end. When the height of the first cavity is equal to the thickness requirement of sediment at the bottom of the pile, the second cavity is sealed by the non-return structure; when the height of the first cavity is larger than the thickness requirement of the pile bottom sediment, the pile bottom sediment supporting plate and the non-return structure open the second cavity so that slurry can enter the second cavity. According to the detection device, whether the thickness of the pile bottom sediment meets the thickness requirement or not is judged by checking whether slurry exists in the second cavity or not, the test method is reliable, and the accuracy of the judgment result is improved.

Description

Technical Field

[0001] The present invention relates to the field of engineering construction, and particularly relates to a detection device for sediment at the bottom of a bored cast-in-place pile and a detection method for the sediment at the bottom of the pile. Background Art

[0002] During the construction of bored cast-in-place piles, it is extremely easy to cause a large sediment thickness at the bottom of the pile due to reasons such as too long idle time after hole formation and too high sand content in the mud. As a result, the following adverse effects are generated: (1) The gravel particles and sand in the sediment will reduce the effective contact area between the pile and the soil, reducing the bearing capacity of the pile foundation; (2) The sediment weakens the adhesion between the pile body and the soil, increasing the risk of pile body deformation and settlement, and affecting the overall stability and safety of the building. (3) The sediment reduces the compactness of the pile body, thereby affecting its compressive strength, and ultimately causing the pile body to be easily cut and cracked, affecting its long-term service performance. Therefore, during actual construction, the sediment thickness at the bottom of the pile needs to be controlled within a reasonable range to ensure the life and use safety of the building.

[0003] Existing detection of sediment at the bottom of the pile mostly uses an ultrasonic sediment detector for detection, but this equipment is expensive and mostly equipped for professional detection agencies. The utilization rate of construction units during actual construction is extremely low, and mostly only relies on construction workers to use a plumb bob measuring rope to determine the sediment thickness during actual application, and the accuracy of the determination result is poor. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defect that the accuracy of the determination result of the sediment thickness at the bottom of a bored cast-in-place pile by construction units during construction in the prior art is poor, and to provide a detection device for sediment at the bottom of a bored cast-in-place pile and a detection method for the sediment at the bottom of the pile.

[0005] The present invention solves the above technical problem through the following technical solutions:

[0006] A detection device for sediment at the bottom of a bored cast-in-place pile, the detection device comprising:

[0007] A housing, the lower end of the housing is open, the upper end of the housing is sealed, and the interior of the housing is hollow;

[0008] A plate member, the plate member is arranged in the housing and can move in the vertical direction, a first cavity is formed between the plate member and the lower end, and the first cavity is used for inserting into the sediment at the bottom of the pile;

[0009] A check structure, the check structure is arranged above the plate member and connected to the plate member, and a second cavity is formed between the check structure and the upper end;

[0010] When the height of the first cavity is equal to the thickness requirement of the pile bottom sediment, the check valve structure seals the second cavity; when the height of the first cavity is greater than the thickness requirement of the pile bottom sediment, the pile bottom sediment supports the plate member and the check valve structure to open the second cavity so that the mud can enter the second cavity.

[0011] In this technical solution, by arranging a plate member and a check valve structure in the housing, and at the same time, a first cavity is formed between the lower end of the plate member and the housing, and a second cavity that can be sealed is formed between the check valve structure and the upper end. By checking whether there is mud in the second cavity, it can be judged whether the thickness of the pile bottom sediment meets the thickness requirement. The test method of this detection device is reliable, which improves the accuracy of the judgment result.

[0012] Specifically, when the detection device is inserted into the pile bottom sediment, when the thickness of the pile bottom sediment is less than or equal to the thickness requirement, that is, when the thickness of the pile bottom sediment is within the range of the thickness requirement, the plate member will not move relative to the housing, the height of the first cavity remains equal to the thickness of the pile bottom sediment, and the check valve structure remains in the state of sealing the second cavity, and the mud will not enter the second cavity. Therefore, when the detection device is retrieved to the ground to check the result, there is no mud in the second cavity, indicating that the thickness of the pile bottom sediment meets the requirement. When the thickness of the pile bottom sediment is greater than the thickness requirement, that is, when the thickness of the pile bottom sediment exceeds the range of the thickness requirement, during the process of inserting the detection device into the pile bottom sediment, when the depth of the housing inserted into the pile bottom sediment is equal to the thickness requirement, the pile bottom sediment will contact the plate member and support the plate member. When the housing continues to move downward, the plate member remains at the top of the pile bottom sediment, so that the plate member can push open the check valve structure, the second cavity is opened, and the mud will enter the second cavity. During the process of taking out the detection device, as the detection device moves upward, the check valve structure will close again. Therefore, when the detection device is retrieved to the ground to check the result, if there is mud in the second cavity, it indicates that the thickness of the pile bottom sediment does not meet the requirement.

[0013] Preferably, the check valve structure includes a fixed fan blade, a movable fan blade and a rotating member. The fixed fan blade is fixed to the housing. The movable fan blade is rotatably connected to the fixed fan blade through the rotating member. The movable fan blade can rotate towards the upper end, and the movable fan blade is connected to the plate member.

[0014] In this technical solution, by arranging a fixed fan blade, a rotating member and a movable fan blade in the check valve structure, the fixed fan blade is first fixed to the housing, and the movable fan blade is rotatably connected to the fixed fan blade through the rotating member. The movable fan blade is supported by the plate member to rotate relative to the housing, so as to realize the opening and closing of the check valve structure. This structure is simple and reliable, and the connection is convenient.

[0015] Preferably, the connection point between the movable fan blade and the plate member is far from the rotating member.

[0016] In this technical solution, by setting the connection point between the movable fan blade and the plate member away from the rotating member, when the plate member supports the rotation of the movable fan blade, the torque received by the movable fan blade is relatively large, and the movable fan blade is easier to rotate, avoiding the situation where the check structure is difficult to open and reducing the accuracy rate of the judgment result.

[0017] Preferably, the connection point between the movable fan blade and the plate member is on the symmetry axis of the movable fan blade

[0018] In this technical solution, by setting the connection point between the movable fan blade and the plate member on the symmetry axis of the movable fan blade, the force on the movable fan blade is more balanced.

[0019] Preferably, the movable fan blade is made of lightweight plastic.

[0020] In this technical solution, by making the movable fan blade of lightweight plastic, the movable fan blade is easier to be pushed open, avoiding the situation where the check structure is difficult to open and reducing the accuracy rate of the judgment result.

[0021] Preferably, the housing includes a main body and a sealing structure, the sealing structure is located at the upper end, and the sealing structure is detachably connected to the main body.

[0022] In this technical solution, by providing a detachable sealing structure, it is more convenient to check whether there is mud in the second chamber.

[0023] Preferably, the main body includes a first part, a middle part and a second part from bottom to top. The height of the first part is the same as the thickness requirement of the sediment at the bottom of the pile. The plate member is placed on the top of the first part. The middle part has a through hole, and the plate member moves inside the middle part. The inner peripheral side of the third part abuts against the outer peripheral side of the check structure.

[0024] Preferably, the sealing structure is a cover, and the cover is threadedly connected to the main body.

[0025] In this technical solution, by setting the sealing structure as a cover and threadedly connecting the cover to the main body, the structure is simple and convenient.

[0026] Preferably, the first part includes a wall-cutting part, the wall-cutting part is located at the lower end, and the wall thickness of the wall-cutting part gradually decreases from top to bottom.

[0027] In this technical solution, by providing the wall-cutting part, the detection device can be inserted into the sediment at the bottom of the pile more smoothly.

[0028] Preferably, the first part is made of steel pipe.

[0029] Preferably, the outer diameter of the plate member is larger than the inner diameter of the first part.

[0030] In this technical solution, by setting the outer diameter of the plate member to be larger than the inner diameter of the first part, the contact area between the pile bottom sediment and the plate member is increased, which can improve the supporting effect of the pile bottom sediment on the plate member and prevent the plate member from sinking into the pile bottom sediment.

[0031] Preferably, the diameter of the middle part gradually increases from bottom to top.

[0032] Preferably, the detection device further includes a rigid support rod, and the plate member and the check structure are connected by the support rod.

[0033] Preferably, the density of the plate member is greater than the density of the slurry.

[0034] In this technical solution, by setting the density of the plate member to be greater than the density of the slurry, the plate member is prevented from floating under the buoyancy of the slurry, and the check structure is prevented from being accidentally opened.

[0035] Preferably, the detection device further includes a lifting lug, and the lifting lug is arranged at the center of the upper end.

[0036] In this technical solution, by arranging a lifting lug at the center of the upper end, it is convenient to hoist the detection device.

[0037] A method for detecting pile bottom sediment, the detection method is performed by using the detection device for pile bottom sediment of bored cast-in-place piles as described above, and the detection method includes the following steps:

[0038] S1: Lower the detection device vertically along the bored cast-in-place pile to the bottom of the bored cast-in-place pile;

[0039] S2: Lift the detection device up to leave the bored cast-in-place pile;

[0040] S3: Check whether there is slurry in the second cavity. If there is slurry in the second cavity, the thickness of the pile bottom sediment does not meet the requirements. If there is no slurry in the second cavity, the thickness of the pile bottom sediment meets the requirements.

[0041] Preferably, in S1, before the slurry fills the area in the shell except the second cavity, lower the detection device at a first speed. After the slurry fills the area in the shell except the second cavity, lower the detection device at a second speed, and the first speed is less than the second speed.

[0042] In this technical solution, before the slurry fills the area in the housing other than the second cavity, the detection device is lowered at a slower first speed to prevent the plate from floating due to the pressure imbalance on the upper and lower sides of the plate. After the slurry fills the area in the housing other than the second cavity, the upper and lower sides of the plate are both filled with slurry and the pressure is balanced. Then, the detection device is lowered at a faster second speed, which can accelerate the detection speed and improve the construction efficiency.

[0043] Preferably, after S1, it further includes S11: lifting and lowering the detection device up and down by a first distance at least twice, and then waiting for a period of time. The first distance is less than the thickness requirement of the sediment at the bottom of the pile.

[0044] In this technical solution, by lifting and lowering the detection device up and down by a first distance less than the thickness requirement of the sediment at the bottom of the pile at least twice and waiting for a period of time, if the sediment at the bottom of the pile exceeds the thickness requirement, the slurry can fully enter the second cavity, avoiding inaccurate judgment results caused by the too short opening time of the check valve structure.

[0045] Preferably, before S3, repeat S1 and S2 at least twice, and the lowering position of the detection device is adjusted to different preset positions each time.

[0046] In this technical solution, the thickness of the sediment at the bottom of the pile is mostly not equal everywhere in the actual working conditions. By performing multiple detections at different preset positions, accidental results can be avoided, and the reliability of the judgment results can be improved.

[0047] The positive and progressive effects of the present invention are as follows: By arranging a plate and a check valve structure in the housing, a first cavity is formed between the plate and the lower end of the housing, and a second cavity that can be sealed is formed between the check valve structure and the upper end. By checking whether there is slurry in the second cavity, it can be judged whether the thickness of the sediment at the bottom of the pile meets the thickness requirement. The test method of this detection device is reliable, and the accuracy of the judgment results is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic perspective view of the detection device according to a preferred embodiment of the present invention.

[0049] Figure 2 It is a schematic cross-sectional view of the detection device according to a preferred embodiment of the present invention.

[0050] Figure 3 It is an exploded view of the detection device according to a preferred embodiment of the present invention.

[0051] Description of the reference numerals:

[0052] Detection device 100

[0053] Housing 1

[0054] The first part 11

[0055] The cutting wall part 111

[0056] The middle part 12

[0057] The through hole 1201

[0058] The second part 13

[0059] The cover 14

[0060] The first cavity 101

[0061] The second cavity 102

[0062] The plate part 2

[0063] The check valve structure 3

[0064] The fixed fan blade 31

[0065] The rotating part 32

[0066] The movable fan blade 33

[0067] The support rod 4

[0068] The lifting lug 5 Specific implementation manners

[0069] The present invention will be further described below by way of embodiments, but the present invention is not limited to the scope of the described embodiments.

[0070] As Figures 1 - 3 shown, this embodiment provides a detection device for the sediment at the bottom of a bored cast-in-place pile. The detection device includes a housing, a plate part and a check valve structure. The lower end of the housing is open, the upper end of the housing is sealed, and the interior of the housing is hollow. The plate part is arranged inside the housing and can move in the vertical direction. A first cavity is formed between the plate part and the lower end, and the first cavity is used to insert into the sediment at the bottom of the pile. The check valve structure is arranged above the plate part and connected to the plate part, and a second cavity is formed between the check valve structure and the upper end. When the height of the first cavity is equal to the thickness requirement of the sediment at the bottom of the pile, the check valve structure seals the second cavity; when the height of the first cavity is greater than the thickness requirement of the sediment at the bottom of the pile, the sediment at the bottom of the pile supports the plate part and the check valve structure to open the second cavity to allow the mud to enter the second cavity. By arranging the plate part and the check valve structure in the housing, and at the same time forming a first cavity between the plate part and the lower end of the housing, and a second cavity that can be sealed between the check valve structure and the upper end, it is possible to judge whether the thickness of the sediment at the bottom of the pile meets the thickness requirement by checking whether there is mud in the second cavity. The test method of this detection device is reliable, improving the accuracy of the judgment result.

[0071] Specifically, when the detection device is inserted into the pile bottom sediment, when the thickness of the pile bottom sediment is less than or equal to the thickness requirement, that is, when the thickness of the pile bottom sediment is within the range of the thickness requirement, the plate member will not move relative to the housing, the height of the first cavity remains equal to the thickness of the pile bottom sediment, the check structure remains in a state of sealing the second cavity, and the mud will not enter the second cavity. Therefore, when the detection device is retrieved to the ground to check the result, if there is no mud in the second cavity, it indicates that the thickness of the pile bottom sediment meets the requirements. When the thickness of the pile bottom sediment is greater than the thickness requirement, that is, when the thickness of the pile bottom sediment exceeds the range of the thickness requirement, during the process of the detection device being inserted downward into the pile bottom sediment, when the depth of the housing inserted into the pile bottom sediment is equal to the thickness requirement, the pile bottom sediment will contact the plate member and have a supporting effect on the plate member. When the housing continues to move downward, the plate member remains at the top of the pile bottom sediment, so that the plate member can push open the check structure, the second cavity is opened, and the mud will enter the second cavity. During the process of taking out the detection device, as the detection device moves upward, the check structure will close again. Therefore, when the detection device is retrieved to the ground to check the result, if there is mud in the second cavity, it indicates that the thickness of the pile bottom sediment does not meet the requirements.

[0072] Specifically in this embodiment, the check structure includes a fixed fan blade, a movable fan blade, and a rotating member. The fixed fan blade is fixed to the housing, the movable fan blade is rotatably connected to the fixed fan blade through the rotating member, the movable fan blade can rotate upward, and the movable fan blade is connected to the plate member. By arranging the fixed fan blade, the rotating member, and the movable fan blade in the check structure, the fixed fan blade is first fixed to the housing, the movable fan blade is rotatably connected to the fixed fan blade through the rotating member, and the movable fan blade is supported by the plate member to rotate relative to the housing, thereby realizing the opening and closing of the check structure. This structure is simple and reliable, and the connection is convenient.

[0073] At the same time, the connection point between the movable fan blade and the plate member is far from the rotating member, and the connection point between the movable fan blade and the plate member is on the axis of symmetry of the movable fan blade. By setting the connection point between the movable fan blade and the plate member to be far from the rotating member, when the plate member supports the movable fan blade to rotate, the moment received by the movable fan blade is larger, and the movable fan blade is easier to rotate, avoiding the situation that the check structure is difficult to open and reducing the accuracy of the judgment result. By setting the connection point between the movable fan blade and the plate member on the axis of symmetry of the movable fan blade, the force on the movable fan blade is more balanced.

[0074] In this embodiment, both the fixed fan blade and the movable fan blade are made of lightweight plastic. By making the movable fan blade of lightweight plastic, the movable fan blade is easier to be pushed open, avoiding the situation that the check structure is difficult to open and reducing the accuracy of the judgment result.

[0075] Of course, in other embodiments, the fixed fan blade may not be provided, and the rotatable movable fan blade may be directly rotatably connected to the housing, which will not be elaborated here.

[0076] In this embodiment, the housing includes a main body and a sealing structure. The sealing structure is located at the upper end and is detachably connected to the main body. By providing a detachable sealing structure, it is more convenient to check whether there is mud in the second chamber.

[0077] Specifically in this embodiment, the sealing structure is a cover, and the cover is threadedly connected to the main body. By setting the sealing structure as a cover and connecting the cover to the main body by threading, the structure is simple and convenient.

[0078] Of course, in other embodiments, the upper end of the housing can also be sealed by other structures in the prior art, such as setting a plug, etc., which will not be elaborated here.

[0079] In this embodiment, the main body includes a first part, a middle part, and a second part from bottom to top. The height of the first part is the same as the thickness requirement of the sediment at the bottom of the pile. The plate is placed on the top of the first part. The middle part has a through hole, and the plate moves inside the middle part. The inner peripheral side of the third part abuts against the outer peripheral side of the check valve structure.

[0080] Among them, the first part includes a tapered wall part, which is located at the lower end, and the wall thickness of the tapered wall part gradually decreases from top to bottom. The length of the tapered wall part can be determined according to actual needs. In this embodiment, the length of the first part is 10 cm, and the length of the tapered wall part can be set to 2 cm. By providing the tapered wall part, the detection device can be inserted into the sediment at the bottom of the pile more smoothly.

[0081] In this embodiment, the outer diameter of the plate is larger than the inner diameter of the first part. By setting the outer diameter of the plate to be larger than the inner diameter of the first part, the contact area between the sediment at the bottom of the pile and the plate is larger, which can improve the supporting effect of the sediment at the bottom of the pile on the plate and prevent the plate from sinking into the sediment at the bottom of the pile.

[0082] At the same time, to enable the mud to enter the area above the plate before the plate leaves the top surface of the first part, through holes are provided on the housing, and the through holes are located in the second part.

[0083] Of course, in other embodiments, the size of the plate can be set so as not to block the channel between the first part and the middle part. The mud can enter above the plate from the lower end of the housing, and through holes may not be provided on the housing. At this time, the horizontal area of the plate should be made as large as possible so that the contact area between the plate and the sediment is larger, which will not be elaborated here.

[0084] In this embodiment, the inner diameter of the middle part is equal to the outer diameter of the first part. That is to say, a support plane formed by the top surface of the first part is formed at the top end of the first part, and the plate can be placed on this support plane.

[0085] The diameter of the middle part gradually increases from bottom to top, and the diameter of the second part is equal to the diameter of the top of the middle part.

[0086] In this embodiment, the detection device further includes a rigid support rod, and the plate member and the check structure are connected by the support rod. The length of the support rod is equal to the distance from the top surface of the placed plate member to the bottom surface of the movable fan blade. The support rod is made of a thin steel pipe, and the support rod needs to ensure sufficient rigidity to fully ensure that it does not undergo elastic deformation during the action process.

[0087] Of course, in other embodiments, the support rod can also be made of other materials. While ensuring that the support rod has sufficient rigidity, it is advisable to use lightweight materials.

[0088] At the same time, in this embodiment, the entire housing is made of steel pipe. The wall thickness of the first part is relatively thicker than that of the middle part and the second part, increasing the weight of the detection device to facilitate the sinking of the detection device.

[0089] In this embodiment, the density of the plate member is slightly greater than the density of the mud. By setting the density of the plate member to be greater than the density of the mud, it is possible to prevent the plate member from floating under the buoyancy of the mud and prevent the check structure from being accidentally opened. The density of the plate member should not be too large. At the same time, the thickness of the plate member should not be too large either. The thickness of the plate member is preferably about 2 mm to prevent the sediment from being unable to support the plate member and pushing open the check structure. The plate member can be made of aluminum.

[0090] In this embodiment, the detection device further includes a lifting lug, and the lifting lug is arranged at the center of the upper end. By arranging the lifting lug at the center of the upper end, it is convenient to hoist the detection device.

[0091] In this embodiment, a method for detecting the sediment at the bottom of a pile is also provided. The detection method is carried out by using the detection device for the sediment at the bottom of a bored cast-in-place pile as described above. The detection method includes the following steps:

[0092] S1: Vertically lower the detection device along the bored cast-in-place pile to the bottom of the bored cast-in-place pile;

[0093] S2: Lift the detection device up to leave the bored cast-in-place pile;

[0094] S3: Check whether there is mud in the second cavity. In response to there being mud in the second cavity, the thickness of the sediment at the bottom of the pile does not meet the requirements. In response to there being no mud in the second cavity, the thickness of the sediment at the bottom of the pile meets the requirements.

[0095] If the device used during the detection is not brand new, before S1, the situation of the detection device can be checked first to ensure that there is no mud in the second cavity and to ensure that the check structure is in the closed state. In S1, attention should be paid to avoiding collision between the detection device and the steel reinforcement cage during the lowering process.

[0096] In S1, before the area in the housing except the second cavity is not filled with mud, lower the detection device at a first speed. After the area in the housing except the second cavity is filled with mud, lower the detection device at a second speed. The first speed is less than the second speed. Before the area in the housing except the second cavity is not filled with mud, lower the detection device at a slower first speed to avoid the floating of the plate due to the pressure imbalance on the upper and lower sides of the plate. After the area in the housing except the second cavity is filled with mud, both the upper and lower sides of the plate are filled with mud and the pressure is balanced. Lower the detection device at a faster second speed, which can accelerate the detection speed and improve the construction efficiency. During the two stages of lowering the detection device, try to keep a uniform speed.

[0097] Meanwhile, after S1, that is, after the detection device is lowered to the bottom of the bored cast-in-place pile, it further includes step S11: lift and lower the detection device up and down by a first distance at least twice, and then wait for a period of time. The first distance is less than the thickness requirement of the sediment at the pile bottom. By lifting and lowering the detection device up and down by a first distance less than the thickness requirement of the sediment at the pile bottom at least twice and waiting for a period of time, for example, waiting for 10 seconds, if the sediment at the pile bottom exceeds the thickness requirement, it can allow the mud to fully enter the second cavity and avoid inaccurate judgment results caused by too short an opening time of the check valve structure. Among them, in addition to being less than the thickness requirement of the sediment at the pile bottom, that is, the amplitude of lifting and lowering the detection device makes the detection device not completely break away from the sediment, the first distance should not be too small to avoid an insignificant lifting and lowering effect. Taking the thickness requirement of the sediment at the pile bottom as 10 cm as an example, the first distance should be greater than 2 cm.

[0098] Before S3, repeat S1 and S2 at least twice, and the lowering position of the detection device is adjusted to different preset positions each time. Since the thickness of the sediment at the pile bottom is mostly not equal everywhere in the actual working conditions, by performing multiple detections at different preset positions, accidental results can be avoided and the reliability of the judgment results can be improved.

[0099] After it is determined that the thickness of the sediment at the pile bottom does not meet the requirements, continue to clean the hole and re-detect until the thickness of the sediment at the pile bottom meets the requirements.

[0100] Meanwhile, after detecting the sediment at the pile bottom of a bored cast-in-place pile, when there is mud in the second cavity, the mud can be cleaned in time for the next detection.

[0101] Although the specific implementation manners of the present invention are described above, those skilled in the art should understand that this is only an example. The protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A detection device for sediment at the bottom of a bored cast-in-place pile, characterized in that, The detection device includes: A housing, the lower end of the housing is open, the upper end of the housing is sealed, and the interior of the housing is hollow; A plate member, the plate member is disposed within the housing and is capable of moving in the vertical direction, a first cavity is formed between the plate member and the lower end, and the first cavity is used to insert into the pile bottom sediment; A check structure, the check structure is disposed above the plate member and is connected to the plate member, a second cavity is formed between the check structure and the upper end; When the height of the first cavity is equal to the thickness requirement of the pile bottom sediment, the check structure seals the second cavity; when the height of the first cavity is greater than the thickness requirement of the pile bottom sediment, the pile bottom sediment supports the plate member and the check structure to open the second cavity so that the mud enters the second cavity.

2. The detecting device for the sediment at the bottom of a bored cast-in-place pile according to claim 1, wherein, The check structure includes a fixed sector, a movable sector and a rotating member, the fixed sector is fixed to the housing, the movable sector is rotatably connected to the fixed sector through the rotating member, the movable sector can rotate towards the upper end, and the movable sector is connected to the plate member.

3. The detecting device for the sediment at the bottom of the bored cast-in-place pile according to claim 2, characterized in that, The connection point between the movable sector and the plate member is far from the rotating member; And / or, the connection point between the movable sector and the plate member is on the axis of symmetry of the movable sector; And / or, the movable sector is made of lightweight plastic.

4. The detecting device for the bottom sediment of a bored cast-in-place pile according to claim 1, characterized in that, The housing includes a main body and a sealing structure, the sealing structure is located at the upper end, and the sealing structure is detachably connected to the main body.

5. The detection device for the pile bottom sediment of a bored cast-in-place pile according to claim 4, wherein The main body includes a first part, a middle part and a second part from bottom to top, the height of the first part is the same as the thickness requirement of the pile bottom sediment, the plate member is placed on the top of the first part, the middle part has a through hole, the plate member moves inside the middle part, and the inner peripheral side of the third part abuts against the outer peripheral side of the check structure; And / or, the sealing structure is a cover, and the cover is threadedly connected to the main body.

6. The detecting device for the bottom sediment of a bored cast-in-place pile according to claim 5, wherein The first part includes a tapered wall portion, the tapered wall portion is located at the lower end, and the wall thickness of the tapered wall portion gradually decreases from top to bottom; And / or, the first part is made of steel pipe; And / or, the outer diameter of the plate member is greater than the inner diameter of the first part; And / or, the diameter of the middle part gradually increases from bottom to top.

7. The detecting device for the sediment at the bottom of the bored cast-in-place pile as claimed in claim 1, wherein The detection device further includes a rigid support rod, and the plate member and the check structure are connected through the support rod; And / or, the density of the plate member is greater than the density of the mud; And / or, the detection device further includes a lifting lug, and the lifting lug is disposed at the center of the upper end.

8. A method for detecting sediment at the bottom of a pile, characterized in that, The detection method is performed by using the detection device for the pile bottom sediment of a bored cast-in-place pile according to any one of claims 1-7, and the detection method includes the following steps: S1: Lower the detection device vertically along the bored cast-in-place pile to the bottom of the bored cast-in-place pile; S2: Lift the detection device up to leave the bored cast-in-place pile; S3: Check whether there is mud in the second cavity. In response to the presence of mud in the second cavity, the thickness of the pile bottom sediment does not meet the requirements. In response to the absence of mud in the second cavity, the thickness of the pile bottom sediment meets the requirements.

9. The method for detecting the sediment at the bottom of a pile according to claim 8, wherein In S1, before the mud fills the area in the housing other than the second cavity, lower the detection device at a first speed. After the mud fills the area in the housing other than the second cavity, lower the detection device at a second speed, and the first speed is less than the second speed.

10. The detection method of sediment at the bottom of a pile according to claim 9, characterized in that, After S1, it further includes S11: Lower and raise the detection device by a first distance at least twice, and then wait for a period of time. The first distance is less than the thickness requirement of the pile bottom sediment. And / or, before S3, repeat S1 and S2 at least twice, and the lowering position of the detection device is adjusted to different preset positions each time.

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