Piezoelectric sound wave sensing foundation pile integrity detection system and setting method

Abstract

The invention discloses a piezoelectric sound wave sensing foundation pile integrity detection system, which comprises a sensing module, a signal acquisition and transmission assembly, a foundation pile hammering module and a data processing terminal, and is characterized in that the sensing module comprises a plurality of segmented piezoelectric cables, and the segmented piezoelectric cables are arranged along the length direction of a foundation pile; the segmented piezoelectric cable is connected with the signal acquisition and transmission assembly, the signal acquisition and transmission assembly is connected with the data processing terminal, the foundation pile hammering module is used for hammering the top of a foundation pile, the signal acquisition and transmission assembly is used for acquiring signals of the segmented piezoelectric cable, and the signals are transmitted to the data processing terminal to be analyzed and processed. According to the method, the distributed detection target can be achieved, the defect that only single-point detection can be carried out in the traditional technology is overcome, compared with a traditional detection means, distributed signal collection can be carried out on the whole length range of the foundation pile by means of the diversified arrangement mode of the segmented piezoelectric cables, blind areas in the detection process are eliminated, and the detection accuracy is improved. Furthermore, the intact state information of each part of the pile body is comprehensively captured, so that the coverage range and the overall systematicness of detection are remarkably enhanced.

Description

Technical Field

[0001] This invention relates to a piezoelectric acoustic wave sensing system for detecting the integrity of foundation piles and its installation method. Background Technology

[0002] In the field of building construction, foundation piles are a critical type of foundation component, and their integrity directly affects the overall safety and stability of the building. Therefore, accurate testing of foundation pile integrity is of great significance. Currently, the commonly used methods for checking foundation pile integrity in the industry mainly include low-strain method, high-strain method, sonic logging method, and core drilling method. However, these traditional detection methods have many shortcomings in practical application: the low-strain method, although simple to operate, is limited by the energy generated by hammering. When facing long piles or piles with complex geological conditions, the signal will attenuate rapidly, making it difficult to accurately determine the specific location and severity of defects at the bottom or deep within the pile; the high-strain method, although it can provide information related to bearing capacity, has high requirements for detection equipment and operating standards, and lacks consistency and accuracy in defect location; the sonic logging method, although having a certain continuous detection capability, requires the pre-embedding of sonic logging tubes inside the pile, which not only increases construction costs and complicates the process, but also greatly reduces the reliability of the detection results if the sonic logging tubes become blocked or misaligned; the core drilling method, as a direct detection method, is a destructive test that will damage the pile structure, and its detection range is narrow, making it impossible to complete continuous detection work along the entire pile length. Furthermore, existing detection technologies still have room for improvement in terms of the accuracy of defect location and the identification of defect severity. Most methods can only roughly determine the existence of defects, but it is difficult to accurately determine their specific location and severity, which brings inconvenience to the assessment of engineering quality. At the same time, for different types of foundation piles (such as precast concrete piles and cast-in-place piles) and foundation piles of different lengths, existing detection methods usually lack a unified and efficient adaptation scheme. Their performance in terms of detection efficiency, cost control, and anti-interference ability is also not ideal, making it difficult to meet the needs of foundation pile full life cycle detection. In recent times, piezoelectric sensing technology has gradually gained attention. Organic piezoelectric materials, such as polyvinylidene fluoride piezoelectric films, have been widely used in engineering fields due to their advantages such as good flexibility, excellent piezoelectric properties, and the ability to be processed into various shapes. In this context, developing a foundation pile integrity detection system and operating method with distributed and continuous detection characteristics, capable of more accurately locating defects and identifying their severity, has become a crucial breakthrough in overcoming current technical challenges and improving the quality of engineering inspections. Summary of the Invention

[0003] To address the above shortcomings, the present invention aims to provide a pile integrity detection system and its setup method based on electroacoustic wave sensing, which features distributed and continuous detection and can more accurately locate defects and identify the degree of defects.

[0004] The technical solution of this invention to solve the above problems is as follows: a foundation pile integrity detection system based on electroacoustic wave sensing, comprising a sensing module, a signal acquisition and transmission component, a foundation pile hammering module, and a data processing terminal. The sensing module includes several segmented piezoelectric cables, which are laid along the length of the foundation pile. The segmented piezoelectric cables are connected to the signal acquisition and transmission component, which is connected to the data processing terminal. The foundation pile hammering module is used to hammer the top of the foundation pile. The signal acquisition and transmission component collects the signals from the segmented piezoelectric cables and transmits them to the data processing terminal for analysis and processing.

[0005] Furthermore, the signal acquisition and transmission component includes a piezoelectric signal acquisition card, a power supply wire, and a data cable. The piezoelectric signal acquisition card includes terminals, the power supply wire is connected to the power supply terminals, the segmented piezoelectric cables are connected to the acquisition terminals of the piezoelectric signal acquisition card via wires, and the piezoelectric signal acquisition card is connected to the data cable. The signal generated by each segmented piezoelectric cable is acquired by the corresponding piezoelectric signal acquisition card and transmitted via the data cable.

[0006] Furthermore, the segmented piezoelectric cable includes a piezoelectric cable body and anchor points, and the piezoelectric signal acquisition card is located in the anchor points; the piezoelectric signal acquisition card is connected to the power supply in parallel through the power supply line, and each acquisition card is responsible for acquiring the signals generated by the cables on its left and right sides.

[0007] Furthermore, the anchor point is provided with a groove, and a portion of the piezoelectric signal acquisition card and piezoelectric cable are installed in the groove and waterproofly encapsulated.

[0008] The present invention also includes a method for setting up a piezoelectric acoustic wave sensing pile integrity detection system. The piezoelectric acoustic wave sensing pile integrity detection system described above is applicable to precast piles and cast-in-place piles. The piezoelectric signal acquisition card is connected to the power supply wire, data cable and segmented piezoelectric cable. The segmented piezoelectric cable is glued to the outside of the precast pile or fixed to the main reinforcement of the reinforcing cage of the cast-in-place pile. Epoxy resin is applied to the piezoelectric cable.

[0009] When the foundation pile is a cast-in-place pile, the segmented piezoelectric cable is first placed on the main reinforcement of the steel cage, and the piezoelectric cable is evenly coated with epoxy resin. The steel cage is then lowered into the pre-drilled hole, and a grouting pipe is placed into the hole. After grouting is completed, a cast-in-place pile with a foundation pile integrity detection system is formed. A protective component is also provided to protect the segmented piezoelectric cable.

[0010] Furthermore, the segmented piezoelectric cable is arranged on the side of the main reinforcement away from the center of the foundation pile, and the stirrups are arranged on the outside of the main reinforcement. The protection component includes a protection box, the bottom of which is arranged on the main reinforcement between two adjacent stirrups. A sliding cover is provided on the side of the protection box away from the center of the foundation pile. The outer wall of the protection box is provided with a sliding groove and a limiting block so that the sliding cover can move along the length of the protection box.

[0011] Furthermore, when the reinforcing cage is lowered into the borehole, the sliding cover cooperates with the protective box to pour concrete for the cast-in-place pile by simultaneously lifting the grouting pipe and pouring the concrete. The sliding cover is lifted synchronously with the grouting pipe during the concrete pouring process, and the bottom of the sliding cover is lower than the grout outlet of the grouting pipe.

[0012] The protective component includes a rotating part sleeved on the main reinforcement bar. The segmented piezoelectric cable is set on the side of the main reinforcement bar facing the center during the lowering of the reinforcement cage. When pouring concrete, the segmented piezoelectric cable is rotated away from the side of the main reinforcement bar facing the center.

[0013] Furthermore, connecting blocks are welded to the corresponding main bars of the reinforcing cage, and stirrups are set on the connecting blocks. The connecting blocks are set on the outside of the main bars. The protective component is also provided with a locking block that can be connected to the locking buckle set on the connecting block. A rotating rod is connected to the rotating component, and the rotating rod extends outside the borehole.

[0014] Beneficial technical effects of the present invention: (1) The present invention can achieve distributed detection target, overcome the shortcomings of traditional technology that can only detect at a single point. Compared with traditional detection methods, it can carry out distributed signal collection over the entire length range of the pile by means of the diversified arrangement of segmented piezoelectric cables, eliminate blind spots in the detection process, and thus fully capture the integrity status information of each part of the pile body, significantly enhancing the coverage and overall system of detection. (2) This invention has continuous monitoring capabilities, which can improve the consistency of data. Existing technologies such as low strain method and high strain method are mostly discrete detection methods. Their signals are easily interrupted due to sudden changes in the pile structure or energy attenuation. However, this system can acquire continuous voltage response data over the entire length of the pile through continuously laid piezoelectric cables and synchronous signal transmission, making defect analysis more consistent and effectively solving the problem of defect misjudgment caused by fragmented data in traditional methods. (3) The present invention provides more accurate location of defects and more reliable identification of defect severity. Traditional technology has a large error when locating defects in deeper parts or minor defects, and it is difficult to quantify the degree of defects. The present invention, combined with wavelet denoising, machine learning and other computing methods of data processing terminal, can control the accuracy of defect location within a smaller range. At the same time, with the help of three-dimensional visualization, it can intuitively distinguish the types of defects (such as diameter reduction, fracture) and severity (such as the proportion of the defect range in the pile cross section), providing a quantifiable reference for the evaluation work. (4) The present invention has lower testing costs and wider applicability. Compared with the acoustic transmission method, which requires the pre-embedding of acoustic tubes, and the core drilling method, which is a destructive test and has high post-repair costs, this system uses segmented piezoelectric cables and modular components, which have lower material costs and can be reused. At the same time, the differentiated layout schemes adopted for different types of foundation piles such as precast piles and cast-in-place piles do not require additional customized equipment, further reducing the cost in the adaptation process and making it more suitable for promotion and application in large-scale projects. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the circuit connection of a segmented piezoelectric cable; Figure 2 This is a schematic diagram of the pile integrity detection using distributed piezoelectric acoustic wave sensing in Example 1; Figure 3 This is a schematic diagram of the installation of the segmented piezoelectric cable in Example 2; Figure 4 This is a schematic diagram of the pile integrity detection system installed on the bored piles in Example 2; Figure 5 This is a schematic diagram of pile integrity testing. Figure 6 This is a side view of the protection component in Example 2; Figure 7 This is a top view of the protection component in Example 2; Figure 8 This is a schematic diagram of the structure of another protective component in Example 2.

[0016] Explanation of reference numerals in the attached diagram: 1. Segmented piezoelectric cable; 2. Pile driving module; 3. Data processing terminal; 4. Precast pile; 5. Cast-in-place pile; 6. Piezoelectric signal acquisition card; 7. Data cable; 8. Anchor point; 9. Epoxy resin; 10. Reinforcing cage; 11. Main reinforcement; 12. Stirrup; 13. Protective box; 14. Sliding cover; 15. Rotating component; 16. Connecting block; 17. Locking block; 18. Power supply wire; 19. Rotating rod. Detailed Implementation

[0017] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0018] Reference Figures 1 to 8 As shown, a piezoelectric acoustic wave sensing-based pile integrity detection system of the present invention includes a sensing module, a signal acquisition and transmission component, a pile hammering module 2, and a data processing terminal 3. The sensing module includes several segmented piezoelectric cables 1, which are laid along the length of the pile. The segmented piezoelectric cables 1 are connected to the signal acquisition and transmission component, which is connected to the data processing terminal 3. The pile hammering module 2 is used to hammer the top of the pile. The signal acquisition and transmission component collects the signals from the segmented piezoelectric cables 1 and transmits them to the data processing terminal 3 for analysis and processing. (Refer to...) Figure 2 , Figure 3 and Figure 4 As shown in this embodiment, several segmented piezoelectric cables 1 are evenly spaced on the pile body. Utilizing the piezoelectric effect and sound wave propagation characteristics of the segmented piezoelectric cables 1, the integrity of the foundation pile is determined by capturing the propagation changes of the stress wave generated by hammering within the pile body. The specific process is as follows: The top of the foundation pile (or a designated location) is hammered manually or by machine to cause vibration and generate stress waves, which propagate longitudinally along the pile body. The segmented piezoelectric cables 1 are tightly coupled to the surface of the pile body (precast pile 4) or the main reinforcement 11 of the steel cage (cast pile 5). When the stress wave propagates to the location of the segmented piezoelectric cables 1, the piezoelectric material in the cable, such as polyvinylidene fluoride, undergoes mechanical deformation due to vibration. Based on the piezoelectric effect, the mechanical energy is converted into a measurable voltage signal. When the stress wave propagation is stable in the intact area of ​​the pile body, the voltage signal waveform is regular, and the amplitude and frequency are stable. If defects exist (such as fractures, necking, or mud inclusions), the stress wave will be reflected, refracted, or its energy will attenuate, resulting in abnormalities such as waveform distortion, sudden drop in amplitude, and frequency shift in the voltage signal output by the cable at the corresponding location. Each anchor point 8 has an embedded piezoelectric signal acquisition card 6 that captures the voltage signal of the corresponding cable segment in real time and aggregates it to the data processing terminal 3 via a data transmission line. The terminal processes the signal using algorithms such as wavelet noise reduction (to eliminate environmental interference) and machine learning (to compare the characteristics of normal / defective signals). Combined with three-dimensional visualization technology, the voltage signal is transformed into an intuitive pile integrity map, accurately locating the defect location (with a small error range) and quantifying the degree of defect (such as the proportion of the defect to the pile cross section).

[0019] In the above embodiments, reference is made to Figure 1As shown, the signal acquisition and transmission component includes a piezoelectric signal acquisition card 6, a power supply wire 18, and a data cable 7. The piezoelectric signal acquisition card 6 includes terminals; the voltage signal acquisition card has four terminals. The upper left and lower left terminals are used to receive the voltage signals acquired by the piezoelectric cable; the upper right terminal is used to connect the positive and negative terminals of the power supply; and the lower right terminal is used to connect the positive and negative terminals of the data cable. The chip is used to collect and preliminarily process the voltage signals acquired by the piezoelectric cable. The signal generated by each segmented piezoelectric cable 1 is acquired by the corresponding piezoelectric signal acquisition card 6 and transmitted through a data cable 7. The segmented piezoelectric cable 1 includes a piezoelectric cable body and an anchor point 8. The piezoelectric signal acquisition card 6 is located in the anchor point 8. The piezoelectric signal acquisition card 6 is connected to the power supply in parallel through the power supply line, and each acquisition card is responsible for acquiring the signals generated by the cables on its left and right sides. The anchor point 8 has a groove, and the piezoelectric signal acquisition card 6 and a part of the piezoelectric cable are installed in the groove and waterproofed. The groove structure of the anchor point 8 of the segmented piezoelectric cable 1 allows for more complete coupling deformation between the piezoelectric cable and the pile / soil, ensuring accurate signal acquisition. On the other hand, the groove can serve as an "encapsulation cavity" to seal the embedded piezoelectric signal acquisition card 6 and the connection between the cable and the acquisition card, such as by filling with waterproof material or using sealant to prevent groundwater and mud from seeping in and protect the core electronic components and line connectors.

[0020] Reference Figure 2 and Figure 4 As shown, the present invention also includes a method for setting up a piezoelectric acoustic wave sensing-based pile integrity detection system, comprising the aforementioned piezoelectric acoustic wave sensing-based pile integrity detection system. This system is applicable to precast piles 4 and cast-in-place piles 5. A piezoelectric signal acquisition card 6 is connected to a power supply wire 18, a data cable 7, and a segmented piezoelectric cable 1. The segmented piezoelectric cable 1 is glued segment by segment to the outside of the precast pile body or fixed to the main reinforcement 11 of the reinforcing cage of the cast-in-place pile 5. Epoxy resin 9 is applied to the segmented piezoelectric cable. The outer surface of the segmented piezoelectric cable 1 is coated with epoxy resin 9. Epoxy resin has excellent waterproof and corrosion-resistant properties, forming a continuous waterproof membrane on the outer layer of the cable, preventing groundwater from penetrating the cable surface into the internal conductors. Simultaneously, the power supply wire 18 and the data cable, as part of the signal acquisition and transmission components, are also covered with epoxy resin along with the cable, forming an overall waterproof system suitable for complex underground environments with moisture and multiple media. (Refer to...) Figure 2 As shown in Example 1, segmented piezoelectric cables 1 are pasted segment by segment onto the outside of the precast foundation pile.

[0021] Reference Figure 3 and 4As shown, the foundation pile is a cast-in-place pile 5. First, the segmented piezoelectric cable 1 is placed on the main reinforcement 11 of the reinforcing cage, and then epoxy resin is evenly coated onto the piezoelectric cable. The reinforcing cage 10 is lowered into the drilled hole, and then a grouting pipe is placed into the hole. After grouting, a cast-in-place pile 5 with a foundation pile integrity detection system is formed. A protective component is also provided to protect the segmented piezoelectric cable 1. In the existing technology, protecting the piezoelectric cable presents certain difficulties. The reinforcing cage is lowered into the drilled hole by a crane. If the piezoelectric cable is placed on the outside of the main reinforcement, it is difficult to avoid contact with the hole wall during the lowering process, which affects the segmented piezoelectric cable. After the reinforcing cage 10 is placed, grouting pipes need to be installed in the hole. Therefore, the stirrups 12 of the reinforcing cage generally need to be placed on the outside of the reinforcing cage 10. The stirrups 12 cannot have bends, because this is to avoid affecting the installation and removal of the grouting pipes. Therefore, although placing the segmented piezoelectric cable on the inside of the main reinforcing bar 11 of the reinforcing cage can prevent damage during lowering, it will interfere with the installation of the grouting pipes. (Refer to...) Figure 6 and Figure 7 As shown, an improved structure is as follows: the segmented piezoelectric cable 1 is set on the side of the main reinforcement 11 away from the center of the foundation pile (i.e., the outer side), the stirrup 12 is set on the outer side of the main reinforcement 11, the protective component includes a protective box 13, the bottom of the protective box 13 is welded to the main reinforcement 11 between two adjacent stirrups 12, the stirrups can be ground thinned, or a connecting block can be set, the protective box 13 is provided with a sliding cover 14 on the side away from the center of the foundation pile, the outer wall of the protective box 13 is provided with a sliding groove and a limiting block so that the sliding cover 14 can move along the length direction of the protective box 13, and a support block can also be set at the rear of the limiting block to avoid the structure from being deformed due to scratches during the lowering process and unable to slide. This structure can avoid the cable being damaged by scratches between the reinforcing cage 10 and the borehole wall. If there is a serious impact and the sliding cover 14 is deformed and cannot move, it needs to be repaired. When the reinforcing cage 10 is lowered into the borehole, the sliding cover 14 cooperates with the protective box 13. When pouring concrete, a pressure machine is needed to apply greater pressure. The protective box 13 is set between the segmented piezoelectric cable 1 and the grouting pipe. The concrete of the cast-in-place pile 5 can also be poured by lifting the grouting pipe while pouring. The sliding cover 14 is lifted synchronously with the grouting pipe during the concrete pouring process, and the bottom of the sliding cover 14 is lower than the grout outlet of the grouting pipe. In this way, the concrete with a certain pressure and speed entering the borehole through the grouting hole is less likely to damage the cable, ensuring the survival rate of the segmented piezoelectric cable 1 during the pouring of the cast-in-place pile 5.

[0022] Reference Figure 8As shown, another structure of the protection component is illustrated: the protection component includes a rotating member 15 sleeved on the main reinforcement 11. The segmented piezoelectric cable 1 is positioned on the center-facing side of the main reinforcement 11 during the lowering of the reinforcing cage 10. During concrete pouring, the segmented piezoelectric cable 1 rotates away from the center-facing side of the main reinforcement 11. A connecting block 16 is welded to the corresponding main reinforcement 11 of the reinforcing cage 10, and a stirrup 12 is positioned on the connecting block 16. The connecting block 16 is positioned on the outside of the main reinforcement 11. The protection component also includes a locking block 17 that can be engaged and fixed with the latches on the connecting block 16. A rotating rod 19 is connected to the rotating member 15, extending outside the borehole. In this embodiment, the piezoelectric cable is positioned inside the reinforcing cage 10 during lowering to avoid friction with the borehole wall. During concrete pouring, the rotating rod 19 drives the rotating member 15 to rotate away from the grouting pipe, protecting its safety during concrete pouring.

[0023] In the above embodiments, the pile driving module 2 includes the following two methods: (1) For piles with a length of less than 30 m, manual hammering is used. (2) For piles with a length greater than 30 m, the weight and stiffness of the pile body increase, and the energy loss during the transmission of energy in the pile body is relatively large. The energy generated by manual hammering may be difficult to effectively transmit to the bottom of the pile. At this time, it is often necessary to use machine hammering to increase the hammering force to ensure that a clear and effective reflection signal can be obtained, so as to accurately judge the integrity of the pile body. The data processing terminal 3 includes a computer and a monitor. The data cable 7 is connected to the computer. The data processing terminal 3 will use wavelet denoising, data selection and machine learning methods to optimize, store and draw the voltage signal, and finally present the voltage data in a three-dimensional visualization form.

Claims

1. A piezoelectric acoustic wave sensing system for detecting the integrity of foundation piles, characterized in that: The system includes a sensing module, a signal acquisition and transmission component, a pile driving module, and a data processing terminal. The sensing module comprises several segmented piezoelectric cables, which are laid along the length of the pile. The segmented piezoelectric cables are connected to the signal acquisition and transmission component, which is connected to the data processing terminal. The pile driving module is used to drive the top of the pile. The signal acquisition and transmission component collects the signals from the segmented piezoelectric cables and transmits them to the data processing terminal for analysis and processing.

2. The piezoelectric acoustic wave sensing-based pile integrity detection system according to claim 1, characterized in that: The signal acquisition and transmission component includes a piezoelectric signal acquisition card, power supply wires, and a data cable. The piezoelectric signal acquisition card includes terminals, and the power supply wires are connected to the power supply terminals. The segmented piezoelectric cables are connected to the acquisition terminals of the piezoelectric signal acquisition card via wires. The piezoelectric signal acquisition card is connected to the data cable. The signal generated by each segmented piezoelectric cable is acquired by the corresponding piezoelectric signal acquisition card and transmitted via the data cable.

3. The piezoelectric acoustic wave sensing-based pile integrity detection system according to claim 2, characterized in that: The segmented piezoelectric cable includes a piezoelectric cable body and anchor points, and the piezoelectric signal acquisition card is located in the anchor points; the piezoelectric signal acquisition card is connected to the power supply in parallel through the power supply line, and each acquisition card is responsible for acquiring the signals generated by the cables on its left and right sides.

4. The piezoelectric acoustic wave sensing-based pile integrity detection system according to claim 3, characterized in that: The anchor point is provided with a groove, and a portion of the piezoelectric signal acquisition card and piezoelectric cable are installed in the groove and waterproofed.

5. A method for setting up a piezoelectric acoustic wave sensing-based pile integrity detection system, comprising the piezoelectric acoustic wave sensing-based pile integrity detection system as described in claim 4, characterized in that: The pile integrity detection system is applicable to both precast piles and cast-in-place piles. The piezoelectric signal acquisition card is connected to the power supply wire, data cable, and segmented piezoelectric cable. The segmented piezoelectric cable is then glued to the outside of the precast pile or fixed to the main reinforcement of the cast-in-place pile's steel cage. Epoxy resin is then applied to the piezoelectric cable.

6. The method for setting up a piezoelectric acoustic wave sensing foundation pile integrity detection system according to claim 5, characterized in that: The foundation pile is a cast-in-place pile. First, the segmented piezoelectric cables are placed on the main reinforcement of the steel cage, and the piezoelectric cables are uniformly coated with epoxy resin. The steel cage is then lowered into the pre-drilled hole, and a grouting pipe is placed into the hole. After grouting is completed, a cast-in-place pile with a foundation pile integrity detection system is formed. A protective component is also provided to protect the segmented piezoelectric cables.

7. The method for detecting the integrity of a foundation pile using piezoelectric acoustic wave sensing according to claim 6, characterized in that: The segmented piezoelectric cable is set on the side of the main reinforcement away from the center of the foundation pile, and the stirrups are set on the outside of the main reinforcement. The protection component includes a protection box. The bottom of the protection box is set on the main reinforcement between two adjacent stirrups. The side of the protection box away from the center of the foundation pile is provided with a sliding cover. The outer wall of the protection box is provided with a sliding groove and a limiting block so that the sliding cover can move along the length of the protection box.

8. The method for detecting the integrity of a foundation pile using piezoelectric acoustic wave sensing according to claim 7, characterized in that: When the reinforcing cage is lowered into the borehole, the sliding cover cooperates with the protective box to pour concrete for the cast-in-place pile by simultaneously lifting the grouting pipe and pouring concrete. The sliding cover is lifted synchronously with the grouting pipe during the concrete pouring process, and the bottom of the sliding cover is lower than the grout outlet of the grouting pipe.

9. The method for detecting the integrity of a foundation pile using piezoelectric acoustic wave sensing according to claim 6, characterized in that: The protective component includes a rotating part sleeved on the main reinforcement bar. The segmented piezoelectric cable is set on the side of the main reinforcement bar facing the center during the lowering of the reinforcement cage. When pouring concrete, the segmented piezoelectric cable is rotated away from the side of the main reinforcement bar facing the center.

10. The method for detecting the integrity of a foundation pile using piezoelectric acoustic wave sensing according to claim 9, characterized in that: Connecting blocks are welded to the corresponding main bars of the reinforcing cage, and stirrups are set on the connecting blocks. The connecting blocks are set on the outside of the main bars. The protective component is also provided with a locking block that can be connected to the locking buckle set on the connecting block. A rotating rod is connected to the rotating component, and the rotating rod extends outside the borehole.

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