A device for detecting the integrity of statically drilled bamboo-joint piles and precast piles using tubular wave testing.

Abstract

This utility model relates to the field of pile foundation testing technology, specifically disclosing a device for detecting the integrity of statically drilled bamboo-joint piles and precast piles using tubular wave propagation. The device includes a testing mechanism, a hammer, and a testing hole. The testing mechanism includes a signal acquisition unit connected to multiple hydrophones via cables, with a distance adjuster between adjacent hydrophones. The hammer strikes the top of the pile to generate stress waves propagating downwards along the pile. The testing hole is located inside the pile, through which the testing mechanism inspects the pile. This utility model uses water filled into the testing hole as the signal propagation medium. The hammer strikes the top of the pile, exciting tubular waves in the water within the testing hole. These waves propagate axially along the testing hole and are reflected and transmitted at impedance differences in the pile, at the liquid surface, and at the bottom of the hole. The hydrophones receive the sound pressure at different depths in the water, arranging them to obtain a wave train diagram. This diagram is then used to analyze the integrity of the pile and the location of defects, improving the accuracy and reliability of pile integrity testing.

Description

Technical Field

[0001] This utility model relates to the field of pile foundation testing technology, and in particular to a statically drilled bamboo-joint pile and a precast pile integrity tube wave testing device. Background Technology

[0002] Pile foundations mainly consist of cast-in-place piles and precast piles. Cast-in-place piles have stable bearing capacity, but their construction costs are high, construction quality is difficult to control, and mud pollution pollutes the environment. Precast piles are easy to construct, but they suffer from soil squeezing during construction and have lower bearing capacity. To solve the problems of traditional pile foundations, a new composite pile technology has emerged. The construction process of inserting prestressed high-strength concrete piles into mixed cement-soil not only improves the pile's bearing capacity and ensures construction efficiency, but also reduces environmental pollution. Currently, statically drilled bamboo-joint piles, as a new type of environmentally friendly pile foundation, have achieved considerable success in engineering practice. They combine high-strength piles with a diameter-enlarging effect, significantly improving vertical compressive strength and lateral friction resistance. They overcome the shortcomings of traditional precast piles, such as low bearing capacity, soil squeezing effect during pile driving, and environmental pollution. This meets the development needs of future construction models and has broad application prospects.

[0003] In practical engineering applications, statically drilled bamboo-joint piles may suffer from issues such as pile misalignment, pile cracks, pile breakage, or weld cracking due to factors like sand settling at the pile bottom, lifting collisions, and mechanical impacts. These problems can affect the pile's bearing capacity and stability. Therefore, integrity testing of statically drilled bamboo-joint piles is crucial for ensuring the quality and safety of subsequent engineering construction. Existing methods for pile quality testing mainly include low-strain reflected wave testing, acoustic wave transmission, side-hole transmission, and core drilling. Due to the unique structure of statically drilled bamboo-joint piles, which contain multiple media in the horizontal direction and exhibit significantly different properties between the pile tip and the surrounding cement-soil in the vertical direction, existing testing methods are limited. The low-strain reflected wave method is affected by factors such as the hardening degree of the surrounding cement-soil, mixing uniformity and proportion, and pile length limitations, and can only identify shallow defects. The impedance difference at the pile-cement-soil interface is weakened, resulting in inaccurate and unreliable pile integrity results. The acoustic transmission method requires a pile diameter greater than 60cm, which is unsuitable for statically drilled bamboo-joint piles and precast piles due to their smaller diameters. The side-hole transmission method is costly and time-consuming, and its limitations in pile length make it difficult to effectively identify the interface between the pile bottom and bedrock. Core drilling has low pile coverage and can damage the pile structure, making it unsuitable for quality testing of statically drilled bamboo-joint piles and precast piles.

[0004] Currently, statically drilled bamboo-joint piles still face problems in practical applications, such as incomplete pile installation, construction-induced pile cracks, pile breakage, or weld cracking. The structure of statically drilled bamboo-joint piles is relatively complex, involving the interaction of multiple media, including the surrounding soil, cement-soil, precast concrete pile, cement-soil inside the pile, and fluid (water) in the pipe. When using traditional testing methods, the propagation of detection signals is affected by complex coupled vibration effects, making it difficult to completely and accurately determine the integrity and quality of statically drilled bamboo-joint piles and precast piles.

[0005] Therefore, in order to accurately detect and evaluate the quality and integrity of statically drilled bamboo-joint piles, there is an urgent need for a device that can improve the accuracy and reliability of pile quality detection. Utility Model Content

[0006] The purpose of this invention is to provide a device for detecting the integrity of statically drilled bamboo-joint piles and precast piles using tubular wave testing, in order to solve the problems existing in the prior art.

[0007] To achieve the above objectives, this utility model provides a device for detecting the integrity of statically drilled bamboo-joint piles and precast piles using tubular wave testing, comprising:

[0008] The testing mechanism is used to test the integrity of the pile body; the testing mechanism includes a signal acquisition device, which is connected to multiple hydrophones via cables, and a distance adjuster is provided between two adjacent hydrophones to adjust the distance between them.

[0009] The testing mechanism also includes a hammer, which is used to strike the top of the pile to generate stress waves that propagate downwards along the pile.

[0010] The detection hole is located inside the pile body, and the detection mechanism uses the detection hole to detect the pile body.

[0011] Preferably, the distance adjuster includes a housing, a reel rotatably connected inside the housing, and openings at opposite ends of the housing, through which the cable is wound around the reel; a limiting component is provided on the outer wall of the housing, the limiting component being used to limit the reel.

[0012] Preferably, the limiting component includes a spool, one end of which is fixedly connected to the center of the spool, and the other end of which passes through the housing and is fixedly connected to a fixing member. The spool is rotatably connected to the housing. A second housing is fixedly connected to the outer wall of the first housing, and the fixing member is disposed inside the second housing. A spring is disposed inside the second housing, and the spring is sleeved on the spool. One end of the spring is fixedly connected to the inner wall of the second housing, and the other end of the spring is fixedly connected to the spool. A fixing bolt is threaded onto the second housing, and the fixing member is fixedly engaged with the second housing through the fixing bolt.

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

[0014] Preferably, the detection hole is a detection tube pre-embedded inside the pile body.

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

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

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

[0018] Compared with the prior art, the present invention has the following advantages and technical effects:

[0019] 1. The selection of inspection holes is flexible and convenient. The bottom-sealed inspection hole uses the middle hole of the bamboo-joint pile body of the bottom-sealed static drill as the inspection hole. There is no need to arrange inspection tubes. It can detect the quality of the pile body concrete in a large area around the tube wall, effectively cover the pile body section, and reflect the condition of each section of the pile body. The core insertion tube inspection hole allows for flexible selection of the type of inspection tube.

[0020] 2. The test signal of this utility model is clear and stable, and can effectively obtain the pile bottom reflection signal of more than 100 meters. Compared with the existing technology, it has a deeper detection depth and can also accurately determine the pile length through the relevant reflection characteristics of the detection curve.

[0021] 3. This utility model has low requirements for equipment and site, and can be applied to a wide range of testing applications.

[0022] 4. It adopts multi-channel, multi-depth hydrophone serial integration technology, supports single-trigger multi-depth synchronous acquisition, simplifies the detection process and reduces the complexity of on-site operations, and has high detection efficiency.

[0023] 5. The test of this utility model can not only accurately detect the integrity of statically drilled bamboo-joint piles, but is also applicable to traditional pile foundations such as precast pipe piles, and has a wide range of applications. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall layout of the hydrophone and distance adjuster of this utility model;

[0026] Figure 2 This is a schematic diagram of the internal structure of the distance adjuster of this utility model;

[0027] Figure 3 This is a schematic diagram of the mainspring in the distance adjuster of this utility model;

[0028] Figure 4 This is a schematic diagram of the integrity tube wave detection of the bottom-sealed static drilling root-planted bamboo joint pile of this utility model;

[0029] Figure 5 This is a schematic diagram of the integrity tube wave detection of the root-planted bamboo joint pile using the core insertion method of this utility model.

[0030] Figure 6 This is a wave train diagram of the defective pile of this utility model;

[0031] Figure 7 This is a wave train diagram of the defective pile of this utility model;

[0032] In the diagram: 1. Hydrophone; 2. Distance adjuster; 3. Cable; 4. Measuring hammer; 5. Signal acquisition device; 6. Detection hole; 21. Housing 1; 22. Fixing bolt; 23. Winding wheel; 24. Winding spool; 25. Fixing component; 26. Spring; 27. Housing 2. Detailed Implementation

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in this utility model can be combined with each other. The described embodiments are merely some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] like Figures 1 to 3 As shown, this utility model provides a device for detecting the integrity of statically drilled bamboo-joint piles and precast piles using tubular wave testing, comprising:

[0035] The testing organization is used to test the integrity of the pile body; the testing organization includes a signal acquisition device 5, which is connected to multiple hydrophones 1 via cables 3, and a distance adjuster 2 is set between two adjacent hydrophones 1 to adjust the distance between two adjacent hydrophones 1.

[0036] The testing mechanism also includes a test hammer 4, which is used to strike the top of the pile to generate stress waves that propagate downwards along the pile.

[0037] Inspection hole 6 is located inside the pile body, and the inspection agency uses inspection hole 6 to inspect the pile body.

[0038] Further optimization of the scheme: the distance adjuster 2 includes a housing 21, a reel 23 is rotatably connected inside the housing 21, and openings are provided at both opposite ends of the housing 21. The cable 3 is wound around the reel 23 through the openings. A limit component is provided on the outer wall of the housing 21 to limit the reel 23.

[0039] Further optimizing the scheme, the limiting component includes a spool 24, one end of which is fixedly connected to the center of the spool 23, and the other end of which passes through the housing 1 21 and is fixedly connected to a fixing member 25. The spool 24 is rotatably connected to the housing 1 21. A housing 27 is fixedly connected to the outer wall of the housing 1 21, and the fixing member 25 is disposed inside the housing 27. A spring 26 is disposed inside the housing 27, and the spring 26 is sleeved on the spool 24. One end of the spring 26 is fixedly connected to the inner wall of the housing 27, and the other end of the spring 26 is fixedly connected to the spool 24. A fixing bolt 22 is threadedly connected to the housing 27, and the fixing member 25 is fixedly engaged with the housing 27 through the fixing bolt 22.

[0040] Further optimization of the scheme results in the shortest distance between two adjacent hydrophones 1 when the spring 26 is in a non-stressed state.

[0041] When adjusting the distance between two adjacent hydrophones 1 using the distance adjuster 2, first rotate the fixing bolt 22 to separate it from the fixing member 25. Then, pull the cables 3 at both ends of the distance adjuster 2. The cables 3 drive the winding wheel 23 to rotate, and the cables on the winding wheel 23 are unwound synchronously, increasing the distance between the two adjacent hydrophones 1. As the winding wheel 23 rotates, it compresses the spring 26 via the winding shaft 24. After the distance between the two adjacent hydrophones 1 is adjusted, the fixing bolt 22 is used to fix the fixing member 25, thus fixing the distance between the two adjacent hydrophones 1. When it is necessary to decrease the distance between the two adjacent hydrophones 1, the fixing bolt 22 is separated from the fixing member 25, and the spring 26 returns to its original position. Under the action of the spring 26, the distance between the two adjacent hydrophones 1 automatically decreases.

[0042] The design was further optimized so that test hole 6 is a test tube pre-embedded inside the pile body.

[0043] The solution has been further optimized, with the testing tube being either a seamless steel pipe or a PVC pipe.

[0044] The design was further optimized so that test hole 6 is the middle hole of the pile body, and the pile body is sealed with concrete.

[0045] The design was further optimized so that the parameters of multiple hydrophones 1 were identical.

[0046] The detection method using the static drilling root-planted bamboo-joint pile and precast pile integrity tube wave detection device provided by this utility model includes the following steps:

[0047] S1, Pile Formation Stage

[0048] The style of the test hole 6 is determined during the pile formation stage. The styles of the test hole 6 include bottom-sealed test hole 6 and core insertion test hole 6.

[0049] like Figure 4 As shown, for the bottom-sealed inspection hole 6, a special drilling rig is used to drill to a set depth, the pile end drill bit enlargement wing is opened, and the hole is enlarged according to the set diameter and height. The bottom of the precast concrete pile is sealed with concrete. When the grouting and mixing of the static drilling and bamboo joint pile construction is just completed, the precast concrete pile with the concrete bottom sealed is inserted into the design elevation of the drill hole filled with cement and soil. Through the solidification of the cement slurry at the pile end and around the pile, the pile and the cement and soil around the pile form a whole, thus forming a composite pile foundation in which the precast pile, the pile end and the cement and soil around the pile jointly bear the load.

[0050] like Figure 5 As shown, for the core insertion type test hole 6, when the static drilling and planting of the bamboo joint pile has just been completed and the cement soil inside the pipe pile has not yet solidified and is in a soft and fluid state, a seamless steel pipe (or PVC pipe) is inserted into the cement soil inside the pipe pile as the test hole 6. After the cement slurry at the pile end and around the pile has solidified, the test pipe, the precast pile, and the cement soil at the pile end and around the pile form an integral whole.

[0051] S2, Water Injection Stage

[0052] Fill the detection hole 6 with clean water and use water as the transmission medium for the tube wave;

[0053] S3, Excitation Acquisition Stage

[0054] Place the hydrophone 1 in the test hole 6 filled with water, use the hammer 4 to vertically strike the top of the pile to generate stress waves, and use the signal acquisition device 5 to collect data and output waveform diagrams.

[0055] S4, Enhanced Testing Phase

[0056] Move the hydrophone 1 upwards from the bottom of the hole and repeat the operation of S3 at regular intervals until it reaches the top of the pile to complete one test.

[0057] At locations where defects exist in the pile, adjust the distance between the hydrophones 1 to achieve closer testing;

[0058] S5, Wavelet Chart Analysis Stage

[0059] The waveforms received at different depths are arranged according to their depth positions to form a wave train diagram, and the results of pile integrity detection are obtained through analysis.

[0060] For the wave train diagram obtained from the complete pile test, the first wave of the tube wave at different depths is continuous and maintains a stable slope along the depth direction. At the same time, the pile length is determined by the tube wave reflected from the pile bottom.

[0061] For wave train diagrams of defective piles, there is a clear delay in the first wave of the tube wave within the defect depth range, and the wave train diagrams exhibit a clear "K"-shaped reflection, representing the tube waves reflected and transmitted at the defect location, respectively. Figure 6 and Figure 7 As shown, the integrity of the pile can be determined by using the wave diagram.

[0062] This invention uses water as the medium for signal propagation in the detection hole 6. The hammer 4 strikes the top of the pile, exciting a pipe wave in the water inside the detection hole 6. The pipe wave, propagating along the axis of the detection hole 6, is reflected and transmitted at the interface of wave impedance difference in the pile body, the liquid surface, the bottom of the hole, and other locations. The hydrophone 1 receives the sound pressure in the water at different depths, arranges them to obtain a wave train diagram, and analyzes the integrity of the pile body and the location of defects based on this diagram, thereby improving the accuracy and reliability of pile integrity detection.

[0063] The above are merely preferred embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the scope of protection of this utility model.

Claims

1. A device for detecting the integrity of statically drilled root-planted bamboo-joint piles and precast piles using tubular wave testing, characterized in that, include: The testing mechanism is used to test the integrity of the pile body; the testing mechanism includes a signal acquisition device (5), which is connected to multiple hydrophones (1) via cables (3), and a distance adjuster (2) is provided between two adjacent hydrophones (1) to adjust the distance between two adjacent hydrophones (1); The testing mechanism also includes a test hammer (4), which is used to strike the top of the pile body to generate stress waves that propagate downward along the pile body; The detection hole (6) is located inside the pile body, and the detection mechanism uses the detection hole (6) to detect the pile body.

2. The device for detecting the integrity of statically drilled bamboo-joint piles and precast piles according to claim 1, characterized in that, The distance adjuster (2) includes a housing (21), inside which a reel (23) is rotatably connected. Openings are provided at opposite ends of the housing (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 housing (21), which is used to limit the reel (23).

3. The device for detecting the integrity of statically drilled bamboo-joint piles and precast piles according to claim 2, characterized in that, The limiting assembly includes a spool (24), one end of which is fixedly connected to the center of the spool (23), and the other end of which passes through the housing (21) and is fixedly connected to a fixing member (25). The spool (24) is rotatably connected to the housing (21). A housing (27) is fixedly connected to the outer wall of the housing (21), and the fixing member (25) is disposed inside the housing (27). A spring (26) is disposed inside the housing (27), and the spring (26) is sleeved on the spool (24). One end of the spring (26) is fixedly connected to the inner wall of the housing (27), and the other end of the spring (26) is fixedly connected to the spool (24). A fixing bolt (22) is threaded onto the housing (27), and the fixing member (25) is fixedly engaged with the housing (27) through the fixing bolt (22).

4. The device for detecting the integrity of statically drilled root-planted bamboo-joint piles and precast piles according to claim 3, characterized in that, When the spring (26) is in a non-stressed state, the distance between two adjacent hydrophones (1) is the shortest.

5. The device for detecting the integrity of statically drilled root-planted bamboo-joint piles and precast piles according to claim 1, characterized in that, The detection hole (6) is a detection tube pre-embedded inside the pile body.

6. The device for detecting the integrity of statically drilled bamboo-joint piles and precast piles according to claim 5, characterized in that, The testing tube is a seamless steel pipe or a PVC pipe.

7. The device for detecting the integrity of statically drilled root-planted bamboo-joint piles and precast piles according to claim 1, characterized in that, The detection hole (6) is the middle hole of the pile body, and the pile body is sealed with concrete.

8. The device for detecting the integrity of statically drilled root-planted bamboo-joint piles and precast piles according to claim 1, characterized in that, The parameters of multiple hydrophones (1) are the same.

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