Static drilling rooted bamboo joint pile and precast pile integrity tube wave detection device and method

Abstract

The invention relates to the technical field of pile foundation detection, and particularly discloses a static drill rooted bamboo joint pile and precast pile integrity tube wave detection device and method.The device comprises a detection mechanism, a measuring hammer and a detection hole, the detection mechanism comprises a signal collector, and the signal collector is connected with a plurality of hydrophones through cables; a distance regulator is arranged between two adjacent hydrophones; the measuring hammer is used for knocking the top of the pile body to generate stress waves spreading downwards along the pile body. The detection hole is formed in the pile body, and the detection mechanism detects the pile body through the detection hole. The detection hole is filled with water as a medium for signal propagation, the pile top is knocked by the measuring hammer to excite tube waves in water in the detection hole, the tube waves propagated in the axial direction of the detection hole can be reflected and transmitted at positions such as a pile body wave impedance difference interface, a liquid level and a hole bottom, and sound pressure in water at different depths is received by the hydrophone; and according to the wave train diagram, pile body integrity and defect positions are analyzed, and the accuracy and reliability of foundation pile integrity detection are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pile foundation detection, and particularly to a static drilling and root-inserting bamboo joint pile and a device and method for detecting the integrity of precast piles by tube waves. Background Art

[0002] Pile foundations mainly include cast-in-place piles and precast piles. Cast-in-place piles have stable bearing capacity, but they have high construction costs, difficult construction quality control, and mud pollution to the environment; precast piles are easy to construct, but there are soil squeezing effects and low bearing capacity during the construction process. To solve the problems existing in traditional pile foundations, a new type of composite pile technology has emerged. The construction technology of inserting prestressed high-strength concrete piles into the mixed cement soil can not only improve the bearing capacity of the pile body, ensure the construction efficiency, but also reduce environmental pollution. At present, the static drilling and root-inserting bamboo joint pile, as a new type of environmental protection pile foundation, has achieved good results in engineering practice. It has both a high-strength pile body and an expanded diameter effect, significantly improving the vertical compressive and lateral friction resistances, overcoming the disadvantages of traditional precast piles such as low bearing capacity, soil squeezing effects and environmental pollution during pile driving construction, meeting the development needs of future construction models, and having broad application prospects.

[0003] In practical engineering applications, the static drilling and root-inserting bamboo joint pile may be affected by factors such as sediment at the pile bottom, lifting collision, and mechanical impact, resulting in problems such as improper pile placement, pile body cracks, broken piles, or weld cracking, thus affecting the bearing capacity and stability of the pile body. Therefore, the integrity detection of the static drilling and root-inserting bamboo joint pile is an important guarantee for the quality and safety of subsequent engineering construction. In the existing technology, the methods for detecting the quality of foundation piles mainly include the low-strain reflected wave method, the acoustic transmission method, the cross-hole transmission method, the core drilling method, etc. Due to the special pile body structure of the static drilling and root-inserting bamboo joint pile, there are not only multiple media in the horizontal direction, but also significant differences in the properties of the pile tip and the surrounding cement soil in the vertical direction. When applying the existing detection methods, the application of the low-strain reflected wave method is affected by factors such as the hardening degree, mixing uniformity and ratio of the surrounding cement soil of the pile, and the pile length limitation, and it can only identify shallow defects. The wave impedance difference at the pile-cement soil interface is weakened, and the obtained pile body integrity results lack accuracy and reliability; since the application of the acoustic transmission method requires the pile diameter of the foundation pile to be greater than 60 cm, the pile diameters of the static drilling and root-inserting bamboo joint pile and the precast pile are relatively small, and the acoustic transmission method is not suitable for detecting the pile body quality; the application cost of the cross-hole transmission method is high, the time consumption is long, and it is difficult to effectively identify the interface between the pile bottom and the bedrock due to the pile length limitation; the core drilling method has a small coverage rate of the pile body and will damage the pile body structure, and is not suitable for the quality detection of the static drilling and root-inserting bamboo joint pile and the precast pile.

[0004] At present, there are still problems in the actual application of static drilling and root-embedded bamboo joint piles, such as incomplete pile embedding, cracks in the pile body caused by construction, pile breakage, or weld cracking. The pile body structure of the static drilling and root-embedded bamboo joint pile is relatively complex, and there are multi-medium interactions among "soil around the pile, cement soil - precast concrete pile - cement soil inside the pile - fluid in the pipe (water)". When applying traditional detection methods, the propagation of detection signals is affected by complex coupling vibration effects, making it difficult to accurately and completely judge the integrity and quality of the static drilling and root-embedded bamboo joint pile and the precast pile body.

[0005] Therefore, in order to accurately detect and evaluate the quality and integrity of the static drilling and root-embedded bamboo joint pile body, a method that can improve the accuracy and reliability of the foundation pile quality detection is urgently needed. Summary of the Invention

[0006] The purpose of the present invention is to provide a device and method for detecting integrity pipe waves of static drilling and root-embedded bamboo joint piles and precast piles to solve the problems existing in the above-mentioned prior art.

[0007] To achieve the above purpose, the present invention provides a device for detecting integrity pipe waves of static drilling and root-embedded bamboo joint piles and precast piles, including:

[0008] A detection mechanism for detecting the integrity of the pile body; the detection mechanism includes a signal collector, the signal collector is connected with a plurality of hydrophones through a cable, and a distance adjuster is arranged between adjacent two of the hydrophones for adjusting the distance between adjacent two of the hydrophones;

[0009] The detection mechanism further includes a sounding hammer for knocking the top of the pile body to generate a stress wave propagating downward along the pile body;

[0010] A detection hole is arranged inside the pile body, and the detection mechanism detects the pile body through the detection hole.

[0011] Preferably, the distance adjuster includes a first shell, a reel is rotatably connected inside the first shell, openings are arranged at both opposite ends of the first shell, and the cable is wound around the reel through the openings; a limiting component is arranged on the outer wall of the first shell for limiting the reel.

[0012] Preferably, the limiting component includes a reel, one end of the reel is fixedly connected to the center of the winding wheel, the other end of the reel penetrates through the housing and is fixedly connected with a fixing piece, and the reel is rotatably connected to the housing; a housing two is fixedly connected to the outer wall of the housing one, and the fixing piece is arranged in the housing two; a clockwork spring is arranged in the housing two, the clockwork spring is sleeved on the reel, one end of the clockwork spring is fixedly connected to the inner wall of the housing two, and the other end of the clockwork spring is fixedly connected to the reel; a fixing bolt is threadedly connected to the housing two, and the fixing piece is fixedly matched with the housing two through the fixing bolt.

[0013] Preferably, when the clockwork spring is in a non-loaded state, the distance between two adjacent hydrophones is the shortest.

[0014] Preferably, the detection hole is a detection pipe embedded inside the pile body.

[0015] Preferably, the detection pipe is a seamless steel pipe or a PVC pipe.

[0016] Preferably, the detection hole is the middle hole of the pile body, and the bottom of the pile body is sealed with concrete.

[0017] Preferably, the parameters of multiple hydrophones are the same.

[0018] A static drilling root-embedded bamboo joint pile and a precast pile integrity pipe wave detection method include the following steps:

[0019] S1. Pile forming stage

[0020] Determine the style of the detection hole during the pile forming stage of the pile body;

[0021] S2. Water injection stage

[0022] Fill the detection hole with clean water and use water as the transmission medium of the pipe wave;

[0023] S3. Excitation and acquisition stage

[0024] Place the hydrophone in the detection hole filled with water, use a sounding hammer to vertically strike the top of the pile body to generate stress waves, and use a signal collector to collect data and output a waveform diagram;

[0025] S4. Lifting and testing stage

[0026] Move the hydrophone upward from the bottom of the hole and repeat the operation of S3 at a certain distance interval until reaching the top of the pile body to complete one detection;

[0027] S5. Wave train diagram analysis stage

[0028] Arrange the waveform diagrams received at different depths according to the depth positions to form a wave train diagram, and analyze to obtain the detection results of the pile body integrity.

[0029] Preferably, the styles of the detection holes include bottom-sealed detection holes and pile core intubation detection holes.

[0030] Compared with the prior art, the present invention has the following advantages and technical effects:

[0031] 1. The selection of the detection holes is flexible and convenient. The bottom-sealed detection hole uses the middle hole in the pile body of the bottom-sealed static drilling and root-planting bamboo joint pile as the detection hole, without the need to arrange detection pipes, and can detect the concrete quality of the pile body in a large range around the pipe wall, effectively covering the cross-section of the pile body and reflecting the conditions of each cross-section of the pile body; for the pile core intubation detection hole, the type of the detection pipe can be flexibly selected.

[0032] 2. The test signal of the test method of the present invention is clear and stable, and can effectively obtain the pile bottom reflection signal up to more than 100 meters. Compared with the prior art, the detection depth is deeper, and the pile length can be accurately determined through the relevant reflection characteristics of the detection curve.

[0033] 3. The test method of the present invention has low requirements for equipment and site, and can be applied to large-scale detection.

[0034] 4. Adopt the multi-channel and multi-depth hydrophone array integration technology, support single-trigger multi-depth synchronous acquisition, simplify the detection process and reduce the complexity of on-site operations, and have high detection efficiency.

[0035] 5. The test of the present invention can not only accurately detect the integrity of the static drilling and root-planting bamboo joint pile, but also be applicable to traditional pile foundations such as precast pipe piles, and has a wide range of applications. Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 It is a general layout schematic diagram of the hydrophone and the distance regulator of the present invention;

[0038] Figure 2 It is an internal structure schematic diagram of the distance regulator of the present invention;

[0039] Figure 3 It is a structural schematic diagram of the clockwork spring in the distance regulator of the present invention;

[0040] Figure 4Schematic diagram of integrity pipe wave detection for the bottom - sealed static drilling and root - planting bamboo - joint pile of the present invention;

[0041] Figure 5 Schematic diagram of integrity pipe wave detection for the core - inserted pipe static drilling and root - planting bamboo - joint pile of the present invention;

[0042] Figure 6 Wave train diagram of the defective pile of the present invention;

[0043] Figure 7 Wave train diagram of the defective pile of the present invention;

[0044] In the figure: 1. Hydrophone; 2. Distance regulator; 3. Cable; 4. Sounding weight; 5. Signal collector; 6. Detection hole; 21. Housing 1; 22. Fixed bolt; 23. Reel; 24. Spindle; 25. Fixing piece; 26. Hairspring; 27. Housing 2. Detailed implementation mode

[0045] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0046] As Figures 1 to 3 shown, the present invention provides a static drilling and root - planting bamboo - joint pile and a device for integrity pipe wave detection of precast piles, including:

[0047] A detection mechanism for detecting the integrity of the pile body; the detection mechanism includes a signal collector 5, the signal collector 5 is connected with a plurality of hydrophones 1 through a cable 3, and a distance regulator 2 is arranged between two adjacent hydrophones 1, and the distance regulator 2 is used to adjust the distance between two adjacent hydrophones 1;

[0048] The detection mechanism further includes a sounding weight 4, and the sounding weight 4 is used to strike the top of the pile body to generate a stress wave propagating downward along the pile body;

[0049] A detection hole 6 is arranged inside the pile body, and the detection mechanism detects the pile body through the detection hole 6.

[0050] In a further optimized scheme, the distance regulator 2 includes a housing 1 (21), a reel 23 is rotatably connected inside the housing 1 (21), openings are arranged at both opposite ends of the housing 1 (21), and the cable 3 is wound around the reel 23 through the openings; a limiting component is arranged on the outer wall of the housing 1 (21), and the limiting component is used to limit the reel 23.

[0051] For a further optimized solution, the limit component includes a reel 24. One end of the reel 24 is fixedly connected to the center of the winding wheel 23. The other end of the reel 24 penetrates through the first housing 21 and is fixedly connected to a fixing member 25. The reel 24 is rotatably connected to the first housing 21. A second housing 27 is fixedly connected to the outer wall of the first housing 21. The fixing member 25 is disposed within the second housing 27. A clockwork spring 26 is disposed within the second housing 27. The clockwork spring 26 is sleeved on the reel 24. One end of the clockwork spring 26 is fixedly connected to the inner wall of the second housing 27. The other end of the clockwork spring 26 is fixedly connected to the reel 24. A fixing bolt 22 is threadedly connected to the second housing 27. The fixing member 25 is fixedly engaged with the second housing 27 through the fixing bolt 22.

[0052] For a further optimized solution, when the clockwork spring 26 is in a non-loaded state, the distance between two adjacent hydrophones 1 is the shortest.

[0053] When using the distance adjuster 2 to adjust the distance between two adjacent hydrophones 1, first rotate the fixing bolt 22 to separate the fixing bolt 22 from the fixing member 25, and then pull the cables 3 at both ends of the distance adjuster 2. The cables 3 drive the winding wheel 23 to rotate. At this time, the cables on the winding wheel 23 are synchronously unreeled, and the distance between two adjacent hydrophones 1 becomes larger. When the winding wheel 23 rotates, the clockwork spring 26 is compressed by driving the reel 24. After the distance between two adjacent hydrophones 1 is adjusted, fix the fixing member 25 through the fixing bolt 22, and the distance between two adjacent hydrophones 1 can be fixed. When it is necessary to reduce the distance between two adjacent hydrophones 1, separate the fixing bolt 22 from the fixing member 25, and the clockwork spring 26 resets. Under the action of the clockwork spring 26, the distance between two adjacent hydrophones 1 automatically becomes smaller.

[0054] For a further optimized solution, the detection hole 6 is a detection pipe embedded inside the pile body.

[0055] For a further optimized solution, the detection pipe is a seamless steel pipe or a PVC pipe.

[0056] For a further optimized solution, the detection hole 6 is a middle hole in the pile body, and the bottom of the pile body is sealed with concrete.

[0057] For a further optimized solution, the parameters of multiple hydrophones 1 are the same.

[0058] A method for detecting the integrity of statically drilled root-inserted bamboo-joint piles and precast piles by tube waves, comprising the following steps:

[0059] S1. Pile forming stage

[0060] Determine the style of the detection hole 6 during the pile forming stage of the pile body. The styles of the detection hole 6 include a bottom-sealed detection hole 6 and a pile core inserted-pipe detection hole 6;

[0061] Such asFigure 4 As shown in the figure, for the bottom-sealing detection hole 6, a special drilling rig is used to drill a hole according to the set depth, the expanding wings of the pile-end drill bit are opened, the hole is enlarged according to the set diameter and height, the bottom of the precast concrete pile is sealed with concrete, and when the grouting and mixing of the static drilling and root-inserting bamboo joint pile are just completed, the precast concrete pile after concrete bottom-sealing is implanted into the designed elevation of the cement-soil-filled drilling hole. Through the solidification of the cement slurry at the pile end and around the pile, the pile, the pile end and the cement soil around the pile form a whole, thus forming a composite pile foundation in which the precast pile, the pile end and the cement soil around the pile jointly bear the load;

[0062] As Figure 5 shown in the figure, for the pile-core inserted-pipe detection hole 6, when the cement soil inside the pipe pile is just completed and has not yet solidified and is in a soft and flowing state during the pile insertion of the static drilling and root-inserting bamboo joint pile, a seamless steel pipe (or PVC pipe) is inserted into the cement soil inside the pipe pile as the detection hole 6. After the cement slurry at the pile end and around the pile solidifies, the detection pipe, the precast pile, the pile end and the cement soil around the pile form a whole.

[0063] S2. Water injection stage

[0064] Fill the detection hole 6 with clear water and use water as the transmission medium for tube waves;

[0065] S3. Vibration excitation and data acquisition stage

[0066] Place the hydrophone 1 in the detection hole 6 filled with water, use the sounding hammer 4 to vertically strike the top of the pile body to generate stress waves, and use the signal collector 5 to collect data and output a waveform diagram;

[0067] S4. Lifting and testing stage

[0068] Move the hydrophone 1 upward from the bottom of the hole and repeat the operation of S3 at certain intervals until reaching the top of the pile body to complete one detection;

[0069] At the place where there are defects in the pile body, adjust the distance between the hydrophones 1 to achieve denser testing;

[0070] S5. Wave train diagram analysis stage

[0071] Arrange the waveform diagrams received at different depths in the order of depth position to form a wave train diagram, and analyze to obtain the pile body integrity detection result.

[0072] For the wave train diagram obtained from the detection of a complete pile, the first waves of the tube waves at different depths are continuous and maintain a stable slope along the depth direction. At the same time, the pile length is determined by the reflected tube wave at the pile bottom.

[0073] For the wave train diagram of a pile with defects, there is an obvious phenomenon of delay in the first wave of the tube wave in the defect depth range, and the wave train diagram shows a clear "K"-shaped reflection, which are the reflected and transmitted tube waves at the defect respectively, as Figure 6 andFigure 7 As shown, based on this, the integrity of the pile shaft can be judged by the wave train diagram.

[0074] In the present invention, the detection hole 6 is filled with water as the medium for signal propagation. The pile top is struck by the sounding hammer 4 to excite the tube wave in the water in the detection hole 6. The tube wave propagating along the axial direction of the detection hole 6 will be reflected and transmitted at the interfaces with different wave impedances of the pile shaft, the liquid surface, the bottom of the hole, etc. The hydrophone 1 receives the sound pressure in the water at different depths, arranges to obtain the wave train diagram, and analyzes the integrity of the pile shaft and the position of the defect based on this, improving the accuracy and reliability of the integrity detection of the foundation pile.

[0075] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A tube wave detection device for the integrity of static drilled rooted bamboo piles and prefabricated piles, characterized in that: include: A detection mechanism, the detection mechanism is used to detect the integrity of the pile body; the detection mechanism comprises a signal collector (5), the signal collector (5) is connected to a plurality of hydrophones (1) via a cable (3), a distance adjuster (2) is provided between two adjacent hydrophones (1), and the distance adjuster (2) is used to adjust the distance between two adjacent hydrophones (1); The detection mechanism further comprises a hammer (4), wherein the hammer (4) is used to strike the top of the pile body to generate a stress wave that propagates downward along the pile body; A detection hole (6), wherein the detection hole (6) is arranged inside the pile body, and the detection mechanism detects the pile body through the detection hole (6).

2. The tube wave detection device for the integrity of statically drilled rooted bamboo piles and prefabricated piles according to claim 1 is characterized in that: The distance adjuster (2) comprises a shell (21), a reel (23) being rotatably connected inside the shell (21), openings being provided at opposite ends of the shell (21), and the cable (3) is wound around the reel (23) through the openings; a limiting component is provided on the outer wall of the shell (21), and the limiting component is used to limit the reel (23).

3. The tube wave detection device for the integrity of static drilled rooted bamboo piles and prefabricated piles according to claim 2 is characterized in that: The limiting assembly comprises a reel (24), one end of the reel (24) is fixedly connected to the center of the reel (23), the other end of the reel (24) passes through the shell one (21) and is fixedly connected to a fixing member (25), the reel (24) is rotatably connected to the shell one (21); a shell two (27) is fixedly connected to the outer wall of the shell one (21), the fixing member (25) is arranged in the shell two (27); a spring (26) is arranged in the shell two (27), the spring (26) is sleeved on the reel (24), one end of the spring (26) is fixedly connected to the inner wall of the shell two (27), and the other end of the spring (26) is fixedly connected to the reel (24); a fixing bolt (22) is threadedly connected to the shell two (27), the fixing member (25) is fixedly matched with the shell two (27) through the fixing bolt (22).

4. The tube wave detection device for the integrity of statically drilled rooted bamboo piles and prefabricated piles according to claim 3 is characterized in that: When the spring spring (26) is in a non-stressed state, the distance between two adjacent hydrophones (1) is the shortest.

5. The tube wave detection device for the integrity of statically drilled rooted bamboo piles and prefabricated piles according to claim 1 is characterized in that: The detection hole (6) is a detection tube pre-buried inside the pile body.

6. The tube wave detection device for the integrity of statically drilled rooted bamboo piles and prefabricated piles according to claim 5 is characterized in that: The detection tube is a seamless steel tube or a PVC tube.

7. The tube wave detection device for the integrity of statically drilled rooted bamboo piles and prefabricated piles according to claim 1 is characterized in that: The detection hole (6) is a middle hole of the pile body, and the pile body is sealed with concrete.

8. The tube wave detection device for the integrity of static drilled rooted bamboo piles and prefabricated piles according to claim 1 is characterized in that: The parameters of the multiple hydrophones (1) are the same.

9. A method for detecting the integrity of statically drilled rooted bamboo piles and prefabricated piles by tube waves, characterized in that: The use of the tube wave detection device for the integrity of the statically drilled rooted bamboo pile and prefabricated pile according to any one of claims 1 to 8 comprises the following steps: S1. Pile formation stage Determining the pattern of the detection hole (6) during the pile body forming stage; S2, water injection stage Fill the detection hole (6) with clean water, using the water as a transmission medium for the tube wave; S3, excitation acquisition stage The hydrophone (1) is placed in a detection hole (6) filled with water, a hammer (4) is used to vertically strike the top of the pile body to generate stress waves, and a signal collector (5) is used to collect data and output a waveform graph; S4, Improvement Test Phase The hydrophone (1) is moved upward from the bottom of the hole and the operation of S3 is repeated at a certain interval until the top of the pile is reached to complete a detection; S5, wave diagram analysis stage The waveforms received at different depths are arranged according to the depth position to form a wave train diagram, and the pile body integrity test results are obtained by analysis.

10. The tube wave detection method for the integrity of static drilled rooted bamboo piles and precast piles according to claim 9 is characterized in that: The detection holes (6) include bottom-sealed detection holes (6) and pile-core intubation detection holes (6).

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