Precast pile integrity detection device and detection method

Abstract

The invention relates to the technical field of precast pile detection, and particularly provides a precast pile integrity detection device and method. The detection device comprises a frame, a first test module, a second test module and an acquisition module. The frame is arranged on the top of a to-be-detected pile foundation, and a lifting control piece is fixed to the frame. The first test module comprises a hammer rod and a hammer head, and the lifting control piece is connected with one end of the hammer rod and used for controlling the hammer rod to lift; the other end of the hammer rod is detachably connected with the hammer head, and the hammer head is located above the pile top of the pile foundation. One end of the second test module is connected with the lifting control member, and the other end is connected with the pile top of the pile foundation. The acquisition module is used for acquiring detection data of the first test module and the second test module. Aiming at the mechanically connected precast pile, the medium strain detection with moderate excitation energy can be provided, the pile head cannot be damaged, and the stress wave can be transmitted to the whole pile length. And meanwhile, medium strain detection and pulling-resistant static load detection are integrated, the application range is larger, and the method is suitable for engineering census.

Description

Technical Field

[0001] The invention relates to the technical field of precast pile detection, and in particular to a precast pile integrity detection device and a detection method. Background Art

[0002] Precast piles are one of the commonly used building materials in construction. Considering the geological conditions of the construction site, on-site construction equipment, and transportation and production costs, it is sometimes necessary to connect two sections of precast piles before use. Depending on the construction requirements, welding and mechanical connection are often used to connect the piles.

[0003] After the pile foundation construction is completed, the pile body needs to be inspected for defects to ensure the quality of the pile foundation project. The low-strain reflection wave method is one of the commonly used integrity detection methods. A vertical excitation force is applied to the top of the pile to generate stress waves in the pile body and propagate downward. The integrity of the pile foundation is determined based on the reflected wave signal.

[0004] Unlike welding, mechanical connection is very likely to produce gaps at the connection of the pile body, resulting in the inability of stress waves to be transmitted to the bottom of the pile. In the prior art, a larger excitation force is set or other detection methods are used to address this problem, which requires the construction site to have a variety of heavy-duty detection devices, which are inconvenient to move, and have a huge impact on the detection cost and efficiency. Summary of the invention

[0005] The precast pile integrity detection device and detection method provided by the embodiments of the present invention at least solve the problem that the stress wave transmission of the precast pile is limited due to the mechanical connection of the piles, making it difficult to detect the integrity of the pile body.

[0006] In a first aspect, the present invention provides a precast pile integrity detection device, which includes: a frame, a first test module, a second test module and a collection module; The frame is arranged on the top of the pile foundation to be inspected, and a lifting control member is fixed on the frame; The first test module is fixed to the lifting control member on the frame; the first test module includes a hammer rod and a hammer head, the lifting control member is connected to one end of the hammer rod, and is used to control the lifting of the hammer rod; the other end of the hammer rod is detachably connected to the hammer head, and the hammer head is located above the pile top of the pile foundation to be tested; The second test module is fixed to the lifting control member on the vehicle frame; one end of the second test module is connected to the lifting control member, and the other end is connected to the top of the pile foundation to be tested; The acquisition module is used to acquire detection data of the first test module and the second test module.

[0007] The precast pile integrity detection device provided by the embodiment of the invention, the lifting control component includes a through-core jack, an oil pump and an upper anchor plate; The oil pump is connected to the through-core jack, and the through-core jack is supported on the bottom surface of the upper anchor plate; One end of the hammer rod away from the hammer head is penetrated into the through-hole jack and is fixedly connected to the upper anchor plate.

[0008] The precast pile integrity detection device provided by the embodiment of the present invention, the second test module comprises a lower anchor plate, a first connecting rod and a second connecting rod; The lower anchor plate is arranged opposite to the upper anchor plate in the vertical direction, and the lower anchor plate is provided with an avoidance hole for the hammer rod to pass through; One end of the first connecting rod is connected to the upper anchor plate, and the other end is connected to the lower anchor plate; One end of the second connecting rod is connected to the lower anchor plate, and the other end is connected to the pile top of the pile foundation to be detected; at least the two ends of the second connecting rod are configured to be detachably connected.

[0009] The precast pile integrity detection device provided by the embodiment of the invention comprises a frame body and a walking crawler; The frame body is arranged around the outer periphery of the first test module and the second test module; the frame body is provided with an escape portion for the hammer rod and the first connecting rod and the second connecting rod to move in the vertical direction, and an escape space for accommodating the lower anchor plate is also provided inside the frame body; The walking crawler is arranged on the bottom surface of the frame body, and the walking crawler is used to move the frame body.

[0010] According to an embodiment of the present invention, a precast pile integrity detection device is provided, wherein the frame body of the vehicle frame is further provided with a first slot body, and the hammer rod is further provided with a second slot body in at least a partial area between the lifting control member and the hammer head; the second slot body and the first slot body both extend in a vertical direction, and the second slot body and the first slot body are matched in a concave-convex manner and are slidably connected.

[0011] In the precast pile integrity detection device provided by the embodiment of the present invention, one end of the hammer rod away from the lifting control member is threadedly connected to the hammer head, or a telescopic member is provided between the one end of the hammer rod away from the lifting control member and the hammer head.

[0012] The prefabricated pile integrity detection device provided by the embodiment of the invention, the collection module includes a displacement meter, a sensor and a collection end; The displacement meter and the sensor are both arranged on the top of the pile foundation to be detected; the collecting end is connected to the displacement meter and the sensor.

[0013] In a second aspect, the present invention also provides a method for detecting the integrity of a precast pile, which is implemented by the precast pile integrity detection device described in any of the above embodiments; the precast pile integrity detection method comprises the following steps: A first stress wave is applied by striking the top of the pile foundation to be tested with an excitation tool, and a low strain test is performed to obtain a first signal waveform; wherein the mass of the excitation tool is less than the total mass of the hammer rod and the hammer head; Judging whether the result of the low strain detection can reflect the integrity of the pile body according to the first signal waveform; completing the detection when the first signal waveform is normal; When the first signal waveform is abnormal, the first test module performs strain detection to obtain a second signal waveform; Judging whether the result of the medium strain detection can reflect the integrity of the pile body according to the second signal waveform; completing the detection when the second signal waveform is normal; When the second signal waveform is abnormal, the second test module performs an anti-pullout test to obtain an anti-pullout curve; The detection result is output according to the pull-out resistance curve.

[0014] The prefabricated pile integrity detection method provided by the embodiment of the present invention, wherein the first test module performs strain detection to obtain a second signal waveform, including: Remove the second connecting rod and lock the hammer head and hammer rod; Start the oil pump switch, the oil cylinder in the through-hole jack is lifted, driving the upper anchor plate, hammer rod and hammer head to lift up, after lifting, press the unloading button, so that the second groove body of the hammer rod slides with the first groove body, the hammer rod and hammer head fall in the vertical direction, hit the pile top of the pile foundation to be tested, and apply the second stress wave to the pile top; The sensor of the acquisition module collects the reflection information of the pile foundation to be detected to obtain the second signal waveform.

[0015] The precast pile integrity detection method provided by the embodiment of the present invention, wherein the second test module performs pull-out detection to obtain a pull-out curve, comprises: Install the second connecting rod and retract or remove the hammer head; Start the oil pump switch, the oil cylinder in the through-hole jack will rise, driving the upper anchor plate, hammer rod, first connecting rod, second connecting rod and lower anchor plate to move upward, and driving the pile foundation to be tested to be pulled up; The displacement meter of the acquisition module records the displacement data in real time and transmits it to the collection end. The acquisition module also collects the force size and time, and generates the pull-out curve according to the real-time load and the displacement data.

[0016] The precast pile integrity detection device and detection method provided by the invention embodiment can solve the quality detection problem of mechanical precast pile connection in one stop; for mechanically connected precast piles, it can provide medium strain detection with moderate excitation energy, which will not cause damage to the pile head and can transmit the stress wave to the entire pile length under normal pile connection. The device compositely integrates medium strain detection and anti-pulling static load detection, has a wider range of application, and is suitable for engineering surveys. The device is easy to move and can detect efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0018] Figure 1 It is a structural schematic diagram of the precast pile integrity detection device in the first embodiment created by the present invention.

[0019] Figure 2 It is a flow chart of the precast pile integrity detection method in the second embodiment of the present invention.

[0020] The above drawings include the following reference numerals: 1—frame; 11—frame body; 12—walking track; 13—avoidance space; 21—through jack; 22—oil pump; 23—upper anchor plate; 31—hammer rod; 32—hammer head; 4—lower anchor plate; 51—first connecting rod; 52—second connecting rod; 61—first trough body; 62—second trough body; 71—displacement meter; 72—sensor; 73—collection end. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings. Embodiment 1

[0024] Prestressed piles are a type of prefabricated piles that are prestressed before the concrete of the pile body is subjected to the service load. Prestressed piles are often used as an ideal foundation form in the construction of high-rise buildings, large industrial buildings, bridge projects, dock buildings, and underground buildings. When constructing in soft soil foundation areas, prestressed piles are required to effectively transfer the load of high-rise buildings to the deep bearing layer with higher bearing capacity. Prestressed piles with high bearing capacity, durability, and anti-buoyancy properties to resist the buoyancy of groundwater are also required in projects such as bridges, underground shopping malls, and underground parking lots. Prestressed piles need to undergo various production quality tests when they are put into construction, including pile body integrity tests.

[0025] Generally, the length of precast piles is about 10 meters, but sometimes a longer pile is needed due to the construction environment requirements, and the designed length needs to be achieved by connecting piles. Sometimes, due to the limitations of transportation roads, transportation vehicles and construction site environment, it is also necessary to first drive a shorter precast pile and then connect the piles for processing. Figure 1 As shown, the obtained prefabricated pile includes an upper section pile and a lower section pile, and the upper section pile and the lower section pile are connected at the connection point. When the integrity of the prefabricated pile after the connection is tested, the corresponding testing problems are also different due to different connection methods.

[0026] Existing methods of connecting piles mainly include welding and mechanical connection. Among them, the pile body obtained by welding has better continuity, and the stress wave applied to the top of the pile can be transmitted to the bottom of the pile, which is convenient for judging the integrity. However, welding requires a dry environment to maintain welding quality. In highly corrosive areas such as the seaside and chemical areas, and in working conditions with high humidity such as rainy and snowy weather, welding cannot be used to connect piles due to environmental factors or material factors. Although the mechanical connection method can solve the above problems to a certain extent, for the mechanical connection method, whether it is filling the joint with sealing materials or setting a clamping mechanical structure, it is possible to leave gaps at the joint of the pile body.

[0027] The normal performance of pile foundation bearing capacity is the fundamental guarantee for building safety. In particular, the failure of pull-out pile joints can easily cause serious safety accidents in underground structures. Pile foundation projects are underground hidden projects, and subsequent remediation is very difficult. Therefore, if there is no effective method for detection and verification, it will leave a large safety hazard for the project. The traditional detection method is low-strain detection. For prefabricated piles processed by mechanical connection, due to the existence of gaps, the stress waves applied by traditional low-strain detection may not be effectively transmitted in the pile body, and the traditional integrity detection method has low accuracy or has the risk of failure.

[0028] In the prior art, in order to address the difficulty in testing the integrity of mechanically connected precast piles, the integrity of the pile body is tested by increasing the hammer energy or performing pull-out tests. However, this solution requires the installation of equipment such as cranes on site to lift heavier hammers, which introduces other problems such as cumbersome device installation, inconvenient transportation of guide frames, and complex and long testing cycles. For mechanically connected precast piles, the prior art lacks a testing device that is easy to transport and has high testing efficiency and is suitable for engineering surveys.

[0029] Accordingly, refer to Figure 1 As shown, Embodiment 1 of the present invention provides a precast pile integrity detection device, which is easy to move and transport, and is suitable for use on construction sites. For mechanically connected prestressed piles, it can provide higher hammer energy than existing excitation tools. The detection device integrates a variety of detection modules, which can realize the switching of multiple detection methods. There is no need to call multiple detection equipment for the same pile foundation to be detected, which improves the efficiency of engineering surveys and the accuracy of integrity detection, and provides a strong basis for integrity judgment.

[0030] Next, the precast pile integrity detection device provided in the first embodiment of the present invention includes a frame 1, a first test module, a second test module and a collection module. Among them, the frame 1 is used to fix the first test module and the second test module, so that the detection device can be transported and moved as a whole through the frame 1. For mechanically connected precast piles, when the low-strain detection fails, the first test module can increase the excitation intensity to re-detect the pile foundation. When the integrity detection of the pile body fails by applying stress waves through excitation, the second test module can perform pull-out detection on the pile foundation without moving the frame 1. The collection module is used to collect the detection data of the first test module and the second test module, and output relevant curves or waveforms through the detection data, so as to judge the integrity of the pile body and output the detection results.

[0031] Specifically, refer to Figure 1As shown, the frame 1 is arranged on the top of the pile foundation to be tested. The frame 1 includes a frame body 11 and a walking track 12. In the first embodiment, the frame body 11 is arranged as an internal hollow column structure, which is arranged around the periphery of the first test module and the second test module. The frame body 11 is provided with a hollow avoidance portion along the axial direction to provide vertical avoidance for the lifting and lowering of the first test module and the second test module. At the same time, an avoidance space 13 is also provided inside the frame body 11 to provide avoidance for the movement of the second test module. The space inside the frame 1 is utilized to provide a loading power and reaction force system for integrity detection, and the joint action between the modules is efficiently utilized.

[0032] Furthermore, a walking track 12 is provided on the bottom surface of the frame body 11, and the walking track 12 is located between the bottom surface of the frame body 11 and the ground. The frame 1 also includes a walking power device, which provides power for the walking track 12. When the walking track 12 moves, it drives the frame body 11, and the first test module and the second test module fixed on the frame body 11 to move together.

[0033] Furthermore, in the first embodiment of the present invention, the frame body 11 and the walking track 12 are both configured with materials and structures having sufficient rigidity, so that they can remain stable when the test module is fixed and lifted and lowered, and are not prone to sliding, tilting or deformation, thereby avoiding affecting the results of the pile body integrity test.

[0034] Specifically, refer to Figure 1 As shown, a lifting control component is also fixed on the vehicle frame 1. The lifting control component connects the first test module and the second test module, and is used to control the lifting or lowering of the test module during the pile body integrity detection. The lifting control component includes a through-hole jack 21, an oil pump 22 and an upper anchor plate 23.

[0035] The oil pump 22 is set as an electric oil pump, which is connected to the through-hole jack 21 through a high-pressure oil pipe. The through-hole jack 21 is supported on the bottom surface of the upper anchor plate 23. When lifting, the switch of the oil pump 22 is turned on, and the oil cylinder in the through-hole jack 21 is lifted to lift the upper anchor plate 23. When falling, the unloading button of the oil pump 22 is turned on, and the oil cylinder in the through-hole jack 21 falls, driving the upper anchor plate 23 to fall. The oil pump 22 is used to drive the jack to lift the hammer, solving the problem of time-consuming and labor-intensive labor.

[0036] In the first embodiment of the present invention, preferably, in order to adapt to the detection requirements of the precast piles and the total mass of the first detection module, the bearing capacity of the through-hole jack 21 is set to 100 tons. In other embodiments, corresponding to different test module masses and pull-out test requirements, the through-hole jack 21 can be set to other bearing specifications.

[0037] Specifically, refer to Figure 1As shown, the first test module is arranged above the pile foundation to be tested. The first test module is arranged as a force hammer, and further, the first test module includes a hammer rod 31 and a hammer head 32. The hammer rod 31 extends in the vertical direction, one end of the hammer rod 31 is connected to the lifting control member, and is specifically arranged inside the through-core jack 21, connected to the upper anchor plate 23, and the other end of the hammer rod 31 is connected to the hammer head 32. When the oil pump 22 is started to drive the upper anchor plate 23 to rise or fall through the through-core jack 21, the hammer rod 31 moves synchronously with the upper anchor plate 23.

[0038] Further, the frame body 11 is provided with a first slot body 61, and a second slot body 62 is provided in at least a part of the area between the through-hole jack 21 and the cone head in the extension direction of the hammer rod 31, and the first slot body 61 and the second slot body 62 are both extended in the vertical direction and matched with each other in a concave-convex manner. Preferably, the second slot body 62 on the hammer rod 31 is formed by the surface of the hammer rod 31 convexly forming a convex groove or a convex block, and the first slot body 61 on the frame body 11 is concavely formed into a groove. When the hammer rod 31 falls, the convex groove or the convex block slides in the groove, and the second slot body 62 is slidably connected with the first slot body 61.

[0039] It should be noted that the area where the first slot 61 is arranged on the frame body 11 needs to be in contact with the surface of the hammer rod 31, and does not interfere with the movement of the second test module in the vertical direction. The second test module includes a plurality of discrete connecting rods, and the area where the first slot 61 is arranged on the frame body 11 is located outside the connecting rods of the second test module on the cross section of the frame body 11.

[0040] The first and second groove bodies 61 and 62 are provided with concave and convex fitting, so that the hammer rod 31 can fall in the vertical direction due to the limitation of the frame body 11 when falling, so that the hammer head 32 can apply force to the pile top of the pile foundation to be tested more evenly, and the integrity test result is more accurate.

[0041] Furthermore, the hammer head 32 is connected to an end of the hammer rod 31 that is away from the upper anchor plate 23 in the extension direction. The hammer head 32 is arranged opposite to the pile top of the pile foundation to be tested and is located above the pile top. When the first detection module performs a pile body integrity test on the pile foundation to be tested, the upper anchor plate 23 of the lifting control component drives the hammer head 32 and the hammer rod 31 to rise and then fall, and the hammer head 32 applies excitation to the pile top when falling.

[0042] It should be noted that when the first test module is performing excitation detection on the pile foundation to be tested to detect the reflected wave signal, the hammer head 32 of the force hammer needs to contact the top of the pile to apply excitation after it falls. That is to say, the hammer head 32 will contact the top of the pile during the lifting and lowering process of the first test module controlled by the lifting control component. When the second detection module performs pull-out detection on the pile foundation to be tested, it is necessary to detect the displacement of the pile top position. Therefore, in order to avoid interference or influence of the hammer head position on the movement of the pile foundation in subsequent pull-out detection, in the first embodiment of the present invention, the end of the hammer rod 31 in the extension direction away from the upper anchor plate 23 is set to be detachably connected with the hammer head 32.

[0043] Next, in some embodiments, the hammer rod 31 and the hammer head 32 are set to be threadedly connected, and the hammer head 32 and the hammer rod 31 are locked by the cooperation of internal and external threads so as to excite the pile top as a force hammer. When performing pull-out test, the hammer head 32 can be disassembled by screwing it. Even if the hammer rod 31 is still raised or lowered synchronously with the upper anchor plate 23, the displacement of the pile foundation in the pull-out test is much smaller than the height of the hammer head 32 in the vertical direction. Therefore, only the hammer head 32 needs to be disassembled to avoid interference with the pile foundation in the pull-out test.

[0044] In other embodiments, a telescopic member may be provided inside the end of the hammer rod 31 connected to the hammer head 32, and the telescopic member is locked to prevent the hammer head 32 from slipping or loosening when the first test module is testing. When the second test module is testing, the hammer head 32 is controlled by the telescopic member to retract in the vertical direction toward the upper anchor plate 23, so as to reserve space for the movement of the pile foundation to be tested.

[0045] In addition, the hammer head 32 and the hammer rod 31 can also be set to other settings that meet the requirements of disassembly and adjustment, but are not limited thereto.

[0046] In the first embodiment of the present invention, the hammer head 32 is in an arc spherical shape, the material of the hammer head 32 is nylon, and the material of the hammer rod 31 is stainless steel. The total mass of the hammer rod 31 and the hammer head 32 is greater than or equal to 40kg and less than or equal to 60kg; preferably, it is set to 50kg. When the total mass of the hammer rod 31 and the hammer head 32 is too large, the frame 1 is inconvenient to move, affecting the test efficiency. When the total mass is too small, the generated excitation intensity is insufficient and it is difficult to transmit from the top of the pile to the bottom of the pile.

[0047] The inventors of this case have found through research that in the prior art, when high-strain testing is performed on the pile foundation to be tested, the total mass of the force hammer that generates excitation is usually more than 1000kg; on the one hand, it is to distinguish it from low-strain testing and generate stronger excitation. On the other hand, the force hammer for high-strain testing is also usually used for bearing capacity testing of the pile foundation to be tested. Therefore, in the first embodiment of the present invention, the total weight of the force hammer is selected as 50kg when testing the integrity of the prefabricated pile body, which can not only be distinguished from the force applied in low-strain testing, but also reasonably reduce the weight of the force hammer, which is convenient for integration on the movable frame 1 for one-stop centralized integrity testing; it can also avoid the situation where the force hammer is too heavy and requires the introduction of counterweights, cranes, guide frames, etc. The excitation energy of the medium-strain detection performed by the first test module is moderate, which will not cause damage to the pile head, and can enable the stress wave to be transmitted to the entire pile length under normal pile connection conditions.

[0048] Specifically, refer to Figure 1 As shown, one end of the second test module is connected to the lifting control member, and the other end is connected to the pile top of the pile foundation to be tested. The second test module is fixed to the lifting control member of the frame 1. The second test module includes a lower anchor plate 4, a first connecting rod 51 and a second connecting rod 52.

[0049] The lower anchor plate 4 is arranged opposite to the upper anchor plate 23 in the vertical direction. One end of the first connecting rod 51 is connected to the upper anchor plate 23, and the other end is connected to the lower anchor plate 4. The upper anchor plate 23 and the lower anchor plate 4 are both square, and the area of ​​the upper anchor plate 23 is larger than the cross-sectional area of ​​the through-hole jack 21. The first connecting rod 51 has at least four vertices that connect the four vertices of the square of the upper anchor plate 23 and the lower anchor plate 4 and maintain stability. Preferably, the first connecting rod 51 is configured as a screw rod and is threadedly connected to the upper anchor plate 23 and the lower anchor plate 4.

[0050] Next, one end of the second connecting rod 52 is connected to the lower anchor plate 4, and the other end is connected to the pile top of the pile foundation to be tested. Preferably, the pile head end plate of the pile top is provided with screw holes along the circumferential direction, and the second connecting rod 52 is provided as a screw rod to be threadedly connected with the pile head end plate and the lower anchor plate 4. The lower anchor plate 4 is provided with an avoidance hole for the hammer rod 31 and the hammer head 32 to pass through. When the lower anchor plate 4 moves, it is located in the avoidance space 13 of the frame 1.

[0051] It should be noted that when the first test module is testing, the hammer head 32 needs to fall on the top of the pile to be tested to generate vibration. In order to prevent the second test module from affecting or interfering with the vibration generated by the falling hammer head 32, at least the two ends of the second connecting rod 52 are set to be detachably connected. When the first test module is testing, the second connecting rod 52 can be disassembled to avoid affecting the test results.

[0052] Specifically, the acquisition module is used to collect the detection data of the first test module and the second test module. The detection data includes the reflection information and displacement data of the pile foundation to be detected. The acquisition module includes a displacement meter 71, a sensor 72 and a collection end 73. The displacement meter 71 and the sensor 72 are installed and fixed on the pile top of the pile foundation to be detected, and the collection end 73 is fixed to the frame 1 and connected with the displacement meter 71 and the sensor 72 for collecting the detection data.

[0053] When the first test module applies excitation, the sensor 72 is used to collect the reflected wave information of the pile foundation, and the sensor 72 is preferably set as an acceleration sensor. When the second test module performs a pull-out test, the displacement meter 71 is used to detect the displacement data of the pile top. Embodiment 2

[0054] Reference Figure 2 As shown, Embodiment 2 provides a precast pile integrity detection method, which is implemented by the precast pile integrity detection device in Embodiment 1. Therefore, the detection method includes all the technical effects of the above detection device, and since the technical effects of the detection device have been described in detail above, they will not be repeated here.

[0055] A method for detecting the integrity of precast piles provided in the second embodiment of the present invention specifically comprises the following steps: Verify the process data of the pile foundation to be tested. The process data of the pile foundation to be tested includes the filling fullness of the sealing material at the pile joint, the pile body size, pile type, concrete strength type and design bearing capacity, as well as the construction date and time, geological condition data and site parameters. By verifying the records of the filling fullness of the sealing material, it provides convenience and preconditions for the implementation of subsequent integrity testing.

[0056] The first stress wave is applied by striking the pile top with an exciting tool, and a low strain detection is performed to obtain a first signal waveform.

[0057] Among them, from the perspective of excitation energy, low-strain detection usually uses a lighter excitation tool to hit the pile top. The total mass of the excitation tool is less than 15kg, which is less than the total mass of the hammer rod 31 and the hammer head 32. In some implementations of Example 2, low-strain detection is usually achieved by manually operating a lighter force hammer to hit, or using a small electromagnetic exciter. In low-strain detection, the strain amplitude of the pile body is generally less than the elastic limit strain of the material.

[0058] After applying the first stress wave, the sensor 72 of the acquisition module collects the first reflection information of the pile foundation to be detected, and the first reflection information is specifically the first reflection wave information. The first signal waveform is obtained according to the first reflection wave information as the result of low strain detection.

[0059] Whether the result of the low strain detection can reflect the integrity of the pile body is determined according to the first signal waveform.

[0060] If the first signal waveform obtained satisfies the waveform curve of Class I defect-free piles, it is considered that the first stress wave can be transmitted from the pile top to the pile bottom, and the result of low-strain detection can be used as the acceptance basis for pile body integrity inspection, completing the pile body integrity inspection. Among them, the waveform curve of Class I defect-free piles is obtained based on the empirical data of engineering surveys.

[0061] If the first signal waveform obtained does not meet the waveform curve of Class I defect-free piles, but has abnormal peaks or troughs, the pile connection reflection is obvious, and the influence of the pile connection on the bearing capacity cannot be judged, it cannot be used as the basis for acceptance, and it is impossible to judge whether the first stress wave has completed the transmission. At this time, the first test module performs strain detection to obtain the second signal waveform.

[0062] The medium strain detection process includes: disassembling the second connecting rod 52, and locking the hammer head 32 and the hammer rod 31. Start the oil pump 22 switch, the oil cylinder in the through-hole jack 21 is lifted, driving the upper anchor plate 23, the hammer rod 31 and the hammer head 32 to lift, and after lifting to a certain height, press the unloading button to make the second slot body 62 of the hammer rod 31 slide with the first slot body 61, and the hammer rod 31 and the hammer head 32 fall in the vertical direction and hit the top of the pile foundation to be detected. Apply a second stress wave to the top of the pile. The sensor 72 of the acquisition module collects the second reflection information of the pile foundation to be detected, and the second reflection information is specifically the second reflection wave information. According to the second reflection wave information, the second signal waveform is obtained as the result of the medium strain detection.

[0063] Whether the result of the strain detection can reflect the integrity of the pile body is determined according to the second signal waveform.

[0064] If the obtained second signal waveform meets the waveform curve of Class I defect-free piles, it is considered that the second stress wave can be transmitted from the pile top to the pile bottom, and the result of the medium strain detection can be used as the acceptance basis for the pile body integrity inspection, and the inspection is completed. Among them, the waveform curve of Class I defect-free piles is obtained based on the empirical data of the engineering survey.

[0065] If the second signal waveform obtained cannot meet the waveform curve of Class I defect-free piles, but has abnormal peaks or troughs, the pile connection reflection is obvious, and it is impossible to judge the impact of the pile connection on the bearing capacity, it cannot be used as the basis for acceptance, and it is impossible to judge whether the second stress wave has completed the transmission. At this time, the second test module performs a pull-out test on the single pile to obtain a pull-out curve. The pull-out test is also called a pull-out static load test, and no excitation is required.

[0066] The pull-out test includes: installing the second connecting rod 52, and retracting or removing the hammer head 32. Starting the oil pump 22 switch, the oil cylinder in the through-hole jack 21 is lifted, driving the upper anchor plate 23, the hammer rod 31, the first connecting rod 51, the second connecting rod 52 and the lower anchor plate 4 to move upward, and driving the pile foundation to be tested to be pulled up through the second test module.

[0067] The maximum lifting stroke of the through-hole jack 21 is 200mm, and the maximum stroke load is greater than the pull-out ultimate bearing capacity of the upper section of the precast pile. In the second embodiment of the present invention, the pull-out static load adopts rapid loading, which is divided into 10 levels of loading, 100kN per level, and each level is held for 1min. The displacement meter 71 of the acquisition module records the displacement data in real time and transmits it to the collection end 73. The acquisition module also collects data such as the force size and time, and generates a U-δ curve as a pull-out curve based on the real-time load U and the displacement δ. The U-δ curve characteristics and load maintenance are used to judge the bearing capacity of the upper section of the pile, and then judge whether the pile connection fails, and output the test results to complete the pile body integrity test. The use of the rapid load maintenance method can not only shorten the static load detection cycle, but also reflect the bearing capacity of the upper section of the pile, providing a very valuable basis for integrity judgment.

[0068] The detection method provided in the second embodiment of the present invention can solve the quality detection problem of mechanically connected precast piles in one stop and eliminate the safety hazards of pile foundation engineering.

[0069] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0070] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0071] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A precast pile integrity detection device, characterized in that: include: A vehicle frame, a first test module, a second test module and a collection module; The frame is arranged on the top of the pile foundation to be inspected, and a lifting control member is fixed on the frame; The first test module is fixed to the lifting control member on the frame; The first test module includes a hammer rod and a hammer head, the lifting control member is connected to one end of the hammer rod and is used to control the lifting of the hammer rod; the other end of the hammer rod is detachably connected to the hammer head, and the hammer head is located above the pile top of the pile foundation to be tested; The second test module is fixed to the lifting control member on the frame; One end of the second test module is connected to the lifting control component, and the other end is connected to the top of the pile foundation to be tested; The acquisition module is used to acquire detection data of the first test module and the second test module.

2. The precast pile integrity detection device according to claim 1, characterized in that: The lifting control components include a through-hole jack, an oil pump and an upper anchor plate; The oil pump is connected to the through-core jack, and the through-core jack is supported on the bottom surface of the upper anchor plate; One end of the hammer rod away from the hammer head is penetrated into the through-hole jack and is fixedly connected to the upper anchor plate.

3. The precast pile integrity detection device according to claim 2, characterized in that: The second test module comprises a lower anchor plate, a first connecting rod and a second connecting rod; The lower anchor plate is arranged opposite to the upper anchor plate in the vertical direction, and the lower anchor plate is provided with an avoidance hole for the hammer rod to pass through; One end of the first connecting rod is connected to the upper anchor plate, and the other end is connected to the lower anchor plate; One end of the second connecting rod is connected to the lower anchor plate, and the other end is connected to the top of the pile foundation to be tested; At least two ends of the second connecting rod are arranged to be detachably connected.

4. The precast pile integrity detection device according to claim 3, characterized in that: The frame includes a frame body and a walking track; The frame body is arranged around the outer periphery of the first test module and the second test module; the frame body is provided with an escape portion for the hammer rod and the first connecting rod and the second connecting rod to move in the vertical direction, and an escape space for accommodating the lower anchor plate is also provided inside the frame body; The walking crawler is arranged on the bottom surface of the frame body, and the walking crawler is used to move the frame body.

5. The precast pile integrity detection device according to claim 1 or 4, characterized in that: The frame body of the frame is also provided with a first slot body, and the hammer rod is also provided with a second slot body in at least a partial area between the lifting control member and the hammer head; the second slot body and the first slot body both extend in a vertical direction, and the second slot body and the first slot body are matched with each other in a concave-convex manner and are slidably connected.

6. The precast pile integrity detection device according to claim 1, characterized in that: One end of the hammer rod away from the lifting control member is threadedly connected to the hammer head, or a telescopic member is arranged between the end of the hammer rod away from the lifting control member and the hammer head.

7. The precast pile integrity detection device according to claim 1, characterized in that: The acquisition module includes a displacement meter, a sensor and a collection terminal; The displacement meter and the sensor are both arranged on the top of the pile foundation to be detected; the collecting end is connected to the displacement meter and the sensor.

8. A method for detecting the integrity of precast piles, characterized in that: The precast pile integrity detection method is implemented by a precast pile integrity detection device as described in any one of claims 1 to 7; the precast pile integrity detection method comprises the following steps: A first stress wave is applied by striking the top of the pile foundation to be tested with an excitation tool, and a low strain test is performed to obtain a first signal waveform; wherein the mass of the excitation tool is less than the total mass of the hammer rod and the hammer head; Judging whether the result of the low strain detection can reflect the integrity of the pile body according to the first signal waveform; completing the detection when the first signal waveform is normal; When the first signal waveform is abnormal, the first test module performs strain detection to obtain a second signal waveform; Judging whether the result of the medium strain detection can reflect the integrity of the pile body according to the second signal waveform; completing the detection when the second signal waveform is normal; When the second signal waveform is abnormal, the second test module performs an anti-pullout test to obtain an anti-pullout curve; The detection result is output according to the pull-out resistance curve.

9. The precast pile integrity detection method according to claim 8, characterized in that: The second signal waveform obtained by the first test module performing strain detection includes: Remove the second connecting rod and lock the hammer head and hammer rod; Start the oil pump switch, the oil cylinder in the through-hole jack is lifted, driving the upper anchor plate, hammer rod and hammer head to lift up, after lifting, press the unloading button, so that the second groove body of the hammer rod slides with the first groove body, the hammer rod and hammer head fall in the vertical direction, hit the pile top of the pile foundation to be tested, and apply the second stress wave to the pile top; The sensor of the acquisition module collects the reflection information of the pile foundation to be detected to obtain the second signal waveform.

10. The precast pile integrity detection method according to claim 8, characterized in that: The pull-out test performed by the second test module to obtain a pull-out curve includes: Install the second connecting rod and retract or remove the hammer head; Start the oil pump switch, the oil cylinder in the through-hole jack will rise, driving the upper anchor plate, hammer rod, first connecting rod, second connecting rod and lower anchor plate to move upward, and driving the pile foundation to be tested to be pulled up; The displacement meter of the acquisition module records the displacement data in real time and transmits it to the collection end. The acquisition module also collects the force size and time, and generates the pull-out curve according to the real-time load and the displacement data.

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