Method for detecting underreamed base obtained by means of composite post-grouting at pile tip

Abstract

The present disclosure relates to the technical field of foundations. Disclosed is a method for detecting an underreamed base obtained by means of composite post-grouting at a pile tip. The method for detecting comprises the following steps: obtaining a detection channel: on the basis of a reserved channel of a pile body, obtaining a detection channel that longitudinally penetrates through an underreamed base; and detection: detecting the underreamed base by means of the detection channel, and using tube wave detection technology to obtain the formation size and grouting reinforcement effect of the underreamed base. The method for detecting an underreamed base obtained by means of composite post-grouting at a pile tip of the present disclosure reduces the detection cost of a single pile and improves the detection efficiency.

Description

A method for detecting the enlarged head at the end of a composite post-grouting pile at the pile bottom.

[0001] Cross-references to related applications

[0002] This disclosure claims priority to Chinese Patent Application No. 202410792783.5, filed on June 19, 2024, entitled "A Method for Detecting an Enlarged Head at the End of a Composite Post-Grouting Pile," the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of foundation technology, specifically to a method for detecting the enlarged head of a composite post-grouting pile end at the pile bottom. Background Technology

[0004] In pile foundation structures, the shape of the enlarged head at the pile bottom affects the bearing capacity and stability of the entire foundation structure; therefore, detecting the shape of the enlarged head is essential. Related technologies primarily utilize cross-hole elastic wave CT and side-hole methods to detect the shape of the enlarged head. However, both methods involve complex detection equipment and require drilling and casing alongside the pile foundation structure for detection. Consequently, among these methods for detecting enlarged heads, single-pile testing is expensive, labor-intensive, and inefficient.

[0005] Overview

[0006] In view of this, this disclosure provides a method for detecting the enlarged head of a composite post-grouting pile end, in order to solve the problems of high cost per pile, large workload, and low efficiency in the detection methods of related technologies.

[0007] This disclosure provides a method for detecting a composite post-grouting pile end enlarged head at the pile bottom. The method includes the following steps: obtaining a detection channel: obtaining a detection channel that runs longitudinally through the enlarged head based on the reserved channel in the pile body; detection: detecting the enlarged head through the detection channel, and obtaining the forming size of the enlarged head and the grouting reinforcement effect using pipe wave detection technology.

[0008] In one alternative embodiment, in the step of obtaining the detection channel, a grouting pipe is pre-embedded in the pile body, and the grouting pipe forms a reserved channel; and / or, the pile body is provided with an intermediate hole, and a reserved channel is formed in the intermediate hole.

[0009] In one alternative embodiment, in the step of obtaining the detection channel, the grouting pipe forms a reserved channel; before the step of obtaining the detection channel, the step of cleaning the grouting pipe is further included: cleaning the grouting pipe with water or compressed gas before the cement grout in the grouting pipe solidifies.

[0010] In one alternative embodiment, in the step of cleaning the grouting pipe, compressed gas is used to clean the cement grout inside the grouting pipe; before the detection step, the method further includes the step of injecting a coupling medium into the detection channel.

[0011] In one alternative implementation, prior to obtaining the inspection channel, the step further includes: post-grouting at the pile bottom: performing post-grouting on the bottom end of the pile body to form an enlarged head.

[0012] In one alternative implementation, in the step of obtaining the test channel, after the drill bit extends into the bottom end of the pile through the reserved channel, the drill bit is used to drill the enlarged head to obtain the test channel.

[0013] In one alternative implementation, the detection step includes the steps of: placing a matching receiving transducer and transmitting transducer within the detection channel; and raising or lowering the receiving transducer and transmitting transducer point by point within the detection channel to obtain the lateral and longitudinal dimensions of the enlarged head and the grouting reinforcement effect.

[0014] In one alternative implementation, during the step of obtaining the detection channel, the radial dimension of the detection channel is greater than the maximum outer diameter of the receiving transducer and the transmitting transducer.

[0015] In one optional implementation, the detection process further includes the step of: detecting the pile body through a reserved channel and using pipe wave detection technology to obtain the forming quality and grouting reinforcement effect of the pile body.

[0016] In one alternative implementation, after the detection step, the step of re-grouting the pile bottom is further included: re-grouting the bottom of the enlarged head again using the detection channel.

[0017] The technical solution disclosed herein utilizes the existing pre-reserved channel in the pile body to obtain a detection channel on the enlarged head. Compared with the cross-hole elastic wave CT method and the side-hole method, this reduces the amount of drilling work, improves work efficiency, and lowers detection costs. Furthermore, the use of pipe wave detection technology in the detection process allows for detection through a single detection channel within the enlarged head, further reducing the workload and improving work efficiency, while also lowering detection costs. Moreover, compared to the cross-hole elastic wave CT method and the side-hole method, the detection equipment for pipe wave detection technology is simpler and has lower detection costs. Therefore, the detection method for the composite post-grouting pile end enlarged head of this disclosed method can effectively reduce the detection cost per pile and improve detection efficiency.

[0018] The above description is merely an overview of the technical solution disclosed herein. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this disclosure more apparent and understandable, specific embodiments of this disclosure are described below. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific embodiments of this disclosure or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1a is a structural schematic diagram of a step in cleaning the grouting pipe in the detection method of the enlarged head of the composite post-grouting pile end in Embodiment 1 of this disclosure.

[0021] Figure 1b is a structural schematic diagram of another step in cleaning the grouting pipe in the detection method of the enlarged head of the composite post-grouting pile end in Embodiment 1 of this disclosure.

[0022] Figure 2 is a structural schematic diagram of a step in obtaining the detection channel in the detection method of the pile bottom composite post-grouting pile end enlargement head according to Embodiment 1 of this disclosure;

[0023] Figure 3 is a structural schematic diagram of one detection step in the detection method of the pile bottom composite post-grouting pile end enlargement head according to Embodiment 1 of this disclosure;

[0024] Figure 4 is a structural schematic diagram of a pile bottom re-grouting step in the detection method of the pile bottom composite post-grouting pile end enlargement head according to Embodiment 1 of this disclosure.

[0025] Figure 5 is a structural schematic diagram of a step in cleaning the grouting pipe in the detection method of the enlarged head of the composite post-grouting pile end in Embodiment 2 of this disclosure.

[0026] Figure 6 is a structural schematic diagram of a step in obtaining the detection channel in the detection method of the pile bottom composite post-grouting pile end enlargement head according to Embodiment 2 of this disclosure.

[0027] Figure 7 is a structural schematic diagram of one of the detection steps in the detection method of the pile bottom composite post-grouting pile end enlargement head according to Embodiment 2 of this disclosure.

[0028] Explanation of reference numerals in the attached drawings: 1. Pile body; 2. Enlarged head; 3. Reserved channel; 31. Grouting pipe; 32. Intermediate hole; 4. Inspection channel; 5. Cleaning pipe; 6. One-way valve; 7. Drilling tool; 71. Drill rod; 72. Drill bit; 8. Pipe wave detection device; 81. Receiving transducer; 82. Transmitting transducer; 83. Transmitter; 84. Recorder; 9. Reinforced structure; 10. Grouting perforated pipe. Specific Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0030] As shown in Figures 1a to 7, according to an embodiment of this disclosure, a method for detecting a post-grouting enlarged head at the pile end of a pile is provided, wherein the enlarged head 2 is post-grouted and formed at the bottom of the pile body 1. Specifically, the detection method includes the following steps:

[0031] Obtain the testing channel: Based on the reserved channel 3 of the pile body 1, obtain the testing channel 4 that penetrates the enlarged head 2 longitudinally;

[0032] Inspection: The enlarged head 2 is inspected through inspection channel 4, and the forming size and grouting reinforcement effect of the enlarged head 2 are obtained by using tube wave detection technology.

[0033] The technical solution of this disclosure utilizes the existing reserved channel 3 of the pile body 1 to obtain the detection channel 4 on the enlarged head 2. Compared with the cross-hole elastic wave CT method and the side-hole method, this reduces the amount of drilling work, improves work efficiency, and lowers detection costs. Furthermore, the detection process employs pipe wave detection technology, which can achieve detection through a single detection channel 4 within the enlarged head 2, further reducing the workload and improving work efficiency, while also lowering detection costs. Moreover, compared to the cross-hole elastic wave CT method and the side-hole method, the detection equipment for pipe wave detection technology is simpler and has lower detection costs. Therefore, the detection method for the enlarged head 2 of the pile foundation disclosed in this invention can effectively reduce the detection cost of a single pile and improve detection efficiency.

[0034] Specifically, the enlarged head 2 of this disclosure is obtained through a composite post-grouting technology at the pile bottom. After the enlarged head 2 solidifies to the design strength, the forming dimensions and grouting reinforcement effect of the enlarged head 2 are detected by obtaining test channels and testing procedures to ensure that the enlarged head 2 has sufficient load-bearing capacity. It is understood that the testing method of this disclosure includes, but is not limited to, testing the pile end enlarged head 2 of the composite post-grouting at the pile bottom, as long as there are similar testing requirements as this disclosure.

[0035] It should be noted that this disclosure does not specifically limit the shape and structure of the enlarged head 2, as long as it meets the design requirements.

[0036] The embodiments of this disclosure are described below with reference to Embodiment 1 and Embodiment 2.

[0037] Example 1

[0038] Referring to Figures 1a to 4, this embodiment takes a bored pile as an example. The pile body 1 is a solid reinforced concrete structure cast in place, and the enlarged head 2 is a frustum-shaped structure obtained by composite post-grouting technology at the pile bottom.

[0039] The detection method for the enlarged head 2 of the pile foundation in this embodiment includes the following steps:

[0040] Obtain the testing channel: Based on the reserved channel 3 of the pile body 1, obtain the testing channel 4 that penetrates the enlarged head 2 longitudinally;

[0041] Inspection: The enlarged head 2 is inspected through inspection channel 4, and the forming size and grouting reinforcement effect of the enlarged head 2 are obtained by using tube wave detection technology.

[0042] The pile body 1 is pre-embedded with a grouting pipe 31, which extends from the top of the pile body 1 to the top of the enlarged head 2 or the interior of the enlarged head 2. Specifically, multiple grouting pipes 31 can be provided, and the multiple grouting pipes 31 are located at different radial positions of the enlarged head 2. The grouting pipes 31 may include closed grouting pipes for closed grouting to form the enlarged head 2, and open grouting pipes for open grouting to connect the enlarged head 2 with the surrounding soil.

[0043] Understandably, closed grouting pipes are typically used to form the detection channel 4 in bored piles. However, in some embodiments not shown in the figures, open grouting pipes can also be used to form the detection channel 4, as long as the location of the open grouting pipe can meet the detection conditions for pipe wave detection of the enlarged head 2.

[0044] Specifically, in the step of obtaining the detection channel 4, after the drill bit extends into the bottom end of the pile body 1 through the reserved channel 3, the drill bit 7 is used to drill the enlarged head 2 to obtain the detection channel 4.

[0045] In the above-described step of obtaining the inspection channel 4, the reserved channel 3 is formed inside the grouting pipe 31. The enlarged head 2 can be drilled using the grouting pipe 31. Furthermore, in the inspection step, the enlarged head 2 can be inspected by inserting the grouting pipe 31 into the inspection channel 4.

[0046] Specifically, as shown in Figures 1a and 1b, before the step of obtaining the detection channel 4, the following step is also included:

[0047] Cleaning the grouting pipe 31: Before the cement grout inside the grouting pipe 31 solidifies, clean the cement grout inside the grouting pipe 31 using water or compressed air. The purpose of cleaning the grouting pipe 31 in this step is to prevent the cement grout from solidifying inside the grouting pipe 31, so as to avoid increasing the difficulty of subsequent drilling.

[0048] In the step of cleaning the grouting pipes 31, in some embodiments, as shown in Figure 1a, each grouting pipe 31 is independently installed, and a one-way valve 6 is provided at the bottom of the grouting pipe 31. The one-way valve 6 can prevent external impurities from entering the grouting pipe 31. At this time, before the grouting operation is completed in each grouting pipe 31 and the cement slurry inside the grouting pipe 31 solidifies, multiple grouting pipes 31 need to be cleaned separately. Specifically, the cleaning pipe 5 is extended to the bottom of the grouting pipe 31, so that the diameter of the cleaning pipe 5 is smaller than the diameter of the grouting pipe 31; water or compressed gas is injected into the grouting pipe 31 through the cleaning pipe 5, and the cement slurry inside the grouting pipe 31 floats upward through the gap between the cleaning pipe 5 and the inner wall of the grouting pipe 31, thereby achieving the purpose of cleaning the grouting pipe 31. Preferably, this step uses high-pressure water to clean the grouting pipe 31, or uses compressed air to clean the grouting pipe 31.

[0049] In some embodiments, as shown in Figure 1b, during the cleaning of the grouting pipe 31, two grouting pipes 31 are connected by a connecting pipe, and one or more one-way valves 6 can be installed on the connecting pipe. In this case, the cleaning of the two connected grouting pipes 31 can be achieved simultaneously. For ease of description, the two connected grouting pipes 31 are defined as grouting pipe one and grouting pipe two. Specifically, the cleaning pipe 5 is inserted to the bottom of grouting pipe one; water or compressed gas is injected into grouting pipe one through the cleaning pipe 5, and the cement slurry in grouting pipe one enters grouting pipe two through the connecting pipe and floats upwards from grouting pipe two, achieving the purpose of cleaning grouting pipe one and grouting pipe two simultaneously.

[0050] Understandably, the specific steps for cleaning the grouting pipe 31 can be adjusted according to the specific structural adaptability of the grouting pipe 31, as long as the purpose of cleaning the cement slurry inside the grouting pipe 31 is achieved.

[0051] Furthermore, in some embodiments, water is used to clean the grouting pipe 31. The cleaned water remains in the reserved channel 3, and after obtaining the detection channel 4, the water enters the detection channel 4 and serves as the coupling medium for subsequent detection steps to achieve the propagation of pipe waves.

[0052] Alternatively, in some embodiments, the grouting pipe 31 is cleaned using compressed gas. In this case, before the detection step, the following step should also be included: injecting a coupling medium, such as water, into the detection channel 4 to enable the propagation of the pipe wave.

[0053] Further, as shown in Figure 2, in the step of obtaining the inspection channel 4, after the pile end enlarged head 2 reaches its design strength, the drill bit 7 is inserted through the reserved channel 3 to the bottom end of the pile body 1, and then the drill bit 7 is used to drill the enlarged head 2. In this step, the drilling range of the drill bit 7 is from the top to the bottom of the enlarged head 2, which is small, efficient, and low-cost. Understandably, the depth of the inspection channel 4 can exceed the bottom of the enlarged head 2 to facilitate subsequent pile bottom grouting operations.

[0054] Specifically, the drilling tool 7 includes a drill rod 71 and a drill bit 72. The drill rod 71 and drill bit 72 extend into the grouting pipe 31 and reach the top of the enlarged head 2 through the grouting pipe 31, drilling a hole inside the enlarged head 2 to form a detection channel 4. The diameters of both the drill rod 71 and the drill bit 72 are smaller than the diameter of the reserved channel 3 (i.e., the grouting pipe 31), and the radial dimension (i.e., diameter) of the drilled detection channel 4 should be larger than the maximum outer diameter of the receiving transducer 81 and the transmitting transducer 82, so that the receiving transducer 81 and the transmitting transducer 82 can move freely up and down during the detection step, achieving tube wave detection of the entire enlarged head 2. For example, the drill bit 72 can be a reaming drill bit 72.

[0055] Further, as shown in Figure 3, in the detection step, the tube wave detection device 8 is used to detect tube waves in the amplifier head 2. Specifically, the tube wave detection device 8 includes a receiving transducer 81, a transmitting transducer 82, a transmitter 83, and a recorder 84. Among them, the transmitter 83 is adapted to excite the transmitting transducer 82 to emit tube wave signals, and the transmitter 83 synchronously triggers a transmission signal to transmit the emitted tube wave signals to the recorder 84.

[0056] Specifically, the detection process includes the following steps:

[0057] The matching receiving transducer 81 and transmitting transducer 82 are placed in the detection channel 4; wherein the receiving transducer 81 and transmitting transducer 82 pass through the reserved channel 3 until they enter the detection channel 4;

[0058] The receiving transducer 81 and the transmitting transducer 82 are raised or lowered point by point within the detection channel 4 to obtain the lateral and longitudinal dimensions of the enlarged head 2 and the grouting reinforcement effect.

[0059] Specifically, in this embodiment, the enlarged head 2 is a frustum-shaped structure, the lateral dimension of the enlarged head 2 refers to the diameter of the enlarged head 2, and the longitudinal dimension of the enlarged head 2 refers to the height of the enlarged head 2.

[0060] Understandably, in the step of obtaining the detection channel 4, this disclosure does not specifically limit the number of detection channels 4, as long as it meets the requirements for tube wave detection of the enlarged head 2. One or more detection channels 4 can be obtained in this step. The specific number of detection channels 4 can be adjusted according to the design dimensions of the enlarged head 2 or the adaptability of the detection area, to achieve detection of the entire enlarged head 2 or its detection area. As shown in Figure 3, when the detection range of one set of tube wave detection devices 8 is insufficient to cover the entire cross-section of the enlarged head 2, two detection channels 4 can be provided. The two sets of tube wave detection devices 8 perform tube wave detection in the two detection channels 4 respectively, thereby achieving coverage of the entire cross-section of the enlarged head 2.

[0061] Furthermore, since the grouting pipe 31 longitudinally penetrates the pile body 1, and during the detection step, the receiving transducer 81 and the transmitting transducer 82 enter the detection channel 4 through the reserved channel 3, the following steps may also be included before or after the enlarged head 2 undergoes wave detection:

[0062] By inspecting the pile body 1 through the reserved channel 3, the forming quality and grouting reinforcement effect of the pile body 1 are obtained using pipe wave detection technology.

[0063] In this step, the pipe wave detection technology can also detect the forming quality and grouting reinforcement effect of the pile body 1 on the outer periphery. Then, the detection of the pile body 1 and the enlarged head 2 can be achieved simultaneously through local drilling, which further reduces the detection cost and improves the detection efficiency.

[0064] Furthermore, prior to the step of obtaining the inspection channel 4, specifically prior to the step of cleaning the grouting pipe 31, the following steps are also included:

[0065] Post-grouting at the bottom of the pile: Post-grouting is performed at the bottom of the pile body 1 to form an enlarged head 2.

[0066] Specifically, a grouting bag and other structures are fixedly installed at the bottom of the pile body 1, and the grouting pipe 31 includes a closed grouting pipe and an open grouting pipe. The closed grouting pipe extends from the top of the pile body 1 into the inside of the grouting bag, while the open grouting pipe extends from the top of the pile body 1 to the outside of the grouting bag. In the above-mentioned post-grouting step at the pile bottom, after the pile is cast and the pile body 1 reaches the required strength, the enlarged head 2 is formed by performing closed-loop post-grouting on the closed grouting pipe, and a connecting grout layer is formed between the enlarged head 2 and the surrounding soil by performing open-loop post-grouting on the open grouting pipe. Two open grouting operations can be performed before and after the closed grouting operation.

[0067] Furthermore, as shown in Figure 4, after the detection step, the following step is also included:

[0068] Re-grouting at the pile bottom: Using the inspection channel 4, grouting is performed again at the bottom of the enlarged head 2 to further reinforce the soil at the pile bottom and improve the pile's bearing capacity.

[0069] Specifically, the re-grouting step at the pile bottom includes:

[0070] The grouting pipe 10 is inserted into the bottom end of the enlarged head 2 through the reserved channel 3 and the inspection channel 4.

[0071] Cement grout is injected into the grouting pipe 10 until a reinforcing structure 9 is formed at the bottom of the enlarged head 2. The cement grout flows from the grouting pipe 10 to the bottom of the enlarged head 2 and splits around the bottom of the enlarged head 2 to form root-like concrete grout veins, which is the aforementioned reinforcing structure 9.

[0072] Understandably, in this embodiment, the diameter of the grouting pipe 10 should be smaller than the diameter of the reserved channel 3 and the detection channel 4, so that it can be inserted to the bottom of the enlarged head 2.

[0073] Furthermore, in the above-mentioned step of obtaining the inspection channel, the drilling depth of the inspection channel 4 can be extended to a predetermined position below the enlarged head 2 to facilitate subsequent pile bottom re-grouting operations. Alternatively, before the pile bottom re-grouting step, the drilling tool 7 can be used to deepen the depth of the inspection channel 4 to meet design requirements.

[0074] Example 2

[0075] Referring to Figures 5 to 7, this embodiment takes a precast pipe pile as an example. The pile body 1 is a precast pipe pile structure. A longitudinally penetrating intermediate hole 32 is formed in the middle of the pile body 1. The enlarged head 2 is a conical structure obtained by the pile bottom composite post-grouting technology.

[0076] The difference between this embodiment and Embodiment 1 is that a central hole 32 is provided in the middle of the pile body 1, and a reserved channel 3 can be formed in the central hole 32.

[0077] Specifically, as shown in Figure 5, a grouting pipe 31 is provided inside the central hole 32, and a reserved channel 3 is formed inside the grouting pipe 31.

[0078] Among them, the grouting pipe 31 includes an open grouting pipe and a closed grouting pipe. In the above-mentioned post-grouting step at the pile bottom, after the pile is grouted and the strength of the pile body 1 reaches the required level, the enlarged head 2 is formed by performing closed post-grouting on the closed grouting pipe, and a connecting grout layer connecting the enlarged head 2 and the surrounding soil foundation is formed by performing open post-grouting on the open grouting pipe.

[0079] Furthermore, when the grouting pipe 31 forms the aforementioned reserved channel 3, the implementation steps of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0080] In some embodiments not shown in the figures, an open grouting pipe is provided in the intermediate hole 32, and the open grouting pipe is set through the enlarged head 2. In this case, after the step of cleaning the open grouting pipe, the above-mentioned detection channel 4 can be directly formed in the open grouting pipe, which can eliminate the drilling step of the drill 7.

[0081] Alternatively, in some embodiments not shown in the figures, the detection channel 4 is directly drilled using the intermediate hole 32. Specifically, in the step of obtaining the detection channel 4, the drill bit 7 extends through the intermediate hole 32 to the top of the enlarged head 2 and drills a hole to form the detection channel 4. Furthermore, before the detection step, a guide tube is placed in the intermediate hole 32 and the detection channel 4. This guide tube is adapted to guide the receiving transducer 81 and the transmitting transducer 82 so that the receiving transducer 81 and the transmitting transducer 82 can move freely up and down within the detection channel 4, thereby enabling the detection of the entire enlarged head 2.

[0082] Although embodiments of the present disclosure have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for detecting the enlarged head of a composite post-grouting pile tip, wherein, The detection method includes: Obtain the detection channel (4): Based on the reserved channel (3) of the pile body (1), obtain the detection channel (4) that runs longitudinally through the enlarged head (2); Inspection: The enlarged head (2) is inspected through the inspection channel (4), and the forming size and grouting reinforcement effect of the enlarged head (2) are obtained by using tube wave detection technology.

2. The method for detecting the enlarged head of the composite post-grouting pile end as described in claim 1, wherein, In the step of obtaining the detection channel (4), the pile body (1) is pre-embedded with a grouting pipe (31), the grouting pipe (31) forming the reserved channel (3); and / or, The pile body (1) is provided with a central hole (32), and the reserved channel (3) is formed in the central hole (32).

3. The method for detecting the enlarged head of the composite post-grouting pile end as described in claim 2, wherein, In the step of obtaining the detection channel (4), the grouting pipe (31) forms the reserved channel (3); Prior to the step of obtaining the detection channel (4), the detection method further includes: Cleaning the grouting pipe (31): Before the cement grout in the grouting pipe (31) solidifies, use water or compressed gas to clean the cement grout in the grouting pipe (31).

4. The method for detecting the enlarged head of the composite post-grouting pile end as described in claim 3, wherein, In the step of cleaning the grouting pipe (31), the cement slurry inside the grouting pipe (31) is cleaned using compressed gas; Prior to the detection step, the detection method further includes injecting a coupling medium into the detection channel (4).

5. The method for detecting the enlarged head of the composite post-grouting pile end as described in claim 1, wherein, Prior to the step of obtaining the detection channel (4), the detection method further includes: Post-grouting at the bottom of the pile: Post-grouting is performed on the bottom end of the pile body (1) to form the enlarged head (2).

6. The method for detecting the enlarged head of the composite post-grouting pile end as described in claim 1, wherein, In the step of obtaining the detection channel (4), after the drill bit (7) extends into the bottom end of the pile body (1) through the reserved channel (3), the drill bit (7) is used to drill the enlarged head (2) to obtain the detection channel (4).

7. The method for detecting the enlarged head of the composite post-grouting pile end as described in claim 1, wherein, The detection steps include: Place the matching receiving transducer (81) and transmitting transducer (82) inside the detection channel (4); The receiving transducer (81) and the transmitting transducer (82) are raised or lowered point by point within the detection channel (4) to obtain the lateral and longitudinal dimensions of the enlarged head (2) and the grouting reinforcement effect.

8. The method for detecting the enlarged head of the composite post-grouting pile end as described in claim 7, wherein, In the step of obtaining the detection channel (4), the radial dimension of the detection channel (4) is greater than the maximum outer diameter of the receiving transducer (81) and the transmitting transducer (82).

9. The method for detecting the enlarged head of the composite post-grouting pile end as described in claim 1, wherein, The detection steps also include: The pile body (1) is detected through the reserved channel (3), and the forming quality and grouting reinforcement effect of the pile body (1) are obtained by using the pipe wave detection technology.

10. The method for detecting the enlarged head of the composite post-grouting pile end according to any one of claims 1-9, wherein, Following the detection step, the detection method further includes: Re-grouting at the bottom of the pile: The bottom of the enlarged head (2) is re-grouted using the detection channel (4).

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