Device and method for detecting low strain of foundation pile of active wharf

Abstract

The invention relates to a low-strain detection device and method for an active wharf foundation pile. The device comprises a detector body used for carrying out low-strain detection on the active wharf foundation pile and an excitation assembly aiming at the active wharf foundation pile. According to the detection device, the fastening cap bolt is obliquely and downwards embedded into the side face of the foundation pile by a certain depth, the bolt cap platform at the top of the fastening cap bolt is vertically excited through the low-strain hammer, kinetic energy of excitation is conducted to the foundation pile through the fastening cap bolt, therefore, an existing structure at the top of the foundation pile is avoided, excitation of the active wharf foundation pile is achieved, and the detection efficiency is improved. And finally, an acceleration sensor is installed on the pile side to receive signals. Compared with a pile side grooving method in foundation pile detection, only one small hole needs to be drilled in the pile side, the collected waveform effect is more accurate and effective, the construction operation difficulty is remarkably reduced, damage to the foundation pile is reduced, the working efficiency is improved, and the safety risk of operation below a wharf is reduced.

Description

Technical Field

[0001] The invention relates to the field of pile integrity detection, and in particular to a low-strain detection device and method for existing wharf piles. Background Art

[0002] The pile integrity test is a very important part of the wharf structure inspection. Since most of the piles are located below the mud surface, their damage status cannot be directly determined. Under the influence of slope deformation, ship collision and other natural environments and use loads, the wharf piles are prone to damage such as fracture, tilt, and dislocation. The piles are also important load-bearing components of the wharf, and their quality directly affects the use of the wharf. The piles are underground hidden projects, and it is impossible to use a simple and intuitive method to detect their quality. In addition, due to the influence of many factors such as construction technology, their quality is difficult to guarantee. Although there are many pile testing technologies at present, various technologies are not very perfect, and the accuracy of judging the integrity of the piles is not high. In particular, the detection of the existing wharf piles is still immature and there is no practical method. Due to the presence of beams (part of the piles have pile caps) and panel structures on the upper part of the existing wharf piles, it is difficult to directly judge the integrity of the pile body using the results of the conventional low-strain reflection wave method, and the test results are controversial.

[0003] At present, the low-strain method is mature and experienced in detecting the integrity of pile foundations under free conditions at the top of the pile. However, when using the traditional detection method - low-strain method to detect the integrity of pile foundations under existing structures, there are more interference factors and constraints, and the development is slow. The theoretical level and practical detection application are not yet very mature, which puts forward higher requirements on the performance of instruments and equipment and the field experience and analysis level of technicians. For the detection of piles under existing structures, a small platform cut on the side of the pile can be used for vertical excitation, and the sensor can be installed on another small platform or a side sensor can be used. However, the construction difficulty of using a small platform under the wharf is large, the operation cycle is long, the damage surface of the pile is large, and the safety risk is high. Therefore, it is urgent to find a method or device that can scientifically and efficiently detect the existing wharf foundation piles, replace the grooving process, reduce the difficulty of the operation, and still provide reliable detection data for the damage of the wharf foundation piles. Summary of the invention

[0004] In order to solve the technical problems existing in the prior art, the present invention provides a low-strain detection device and method for existing wharf foundation piles.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] like Figure 1-4As shown, a low-strain detection device for active wharf foundation piles includes a detector body and an excitation component for the active piles, the detector body is connected to a side-attached acceleration sensor via a data line, the excitation component is arranged on the side surface of the active pile, and the side-attached acceleration sensor is tightly attached to the side surface of the active pile; the excitation component includes a low-strain hammer, a fastening cap bolt and a side-attached acceleration sensor; the fastening cap bolt is fixed obliquely downward on the side surface of the active pile by drilling a hole; the side-attached acceleration sensor is tightly attached to the side surface of the active pile by special plasticine.

[0007] As a preferred technical solution, a low-strain hammer is used to vertically excite the cap platform on the top of the fastening cap bolt, so as to transmit the vibration to the existing foundation piles through the fastening cap bolt, and data is collected through a side-mounted acceleration sensor to achieve low-strain detection of the existing wharf foundation piles.

[0008] As a preferred technical solution, fastening cap bolts are implanted on the sides of the existing wharf piles by drilling holes, and the kinetic energy is transmitted to the piles by means of a cap platform of the fastening cap bolts which is vertically excited, so as to perform low-strain detection on the existing wharf piles.

[0009] As a preferred technical solution, low-strain detection is carried out on the existing wharf foundation piles by drilling holes, implanting fastening cap bolts and side-attached acceleration sensors.

[0010] As a preferred technical solution, the fastening cap bolt is removed after the inspection is completed, and the drilled hole formed is repaired with waterproof and anti-corrosion materials.

[0011] As a preferred technical solution, a method for using a low-strain detection device for an existing wharf foundation pile comprises the following steps:

[0012] Step 1: Set an excitation point on the foundation piles that need to be tested for low strain under the active wharf. To facilitate drilling and excitation, the excitation point should be more than 30 cm away from the pile top and the water surface. After the excitation point is determined, use a handheld electric drill to drill a hole with a diameter of 10 mm and a depth of 40 mm at a 45° angle downward at the test point. After cleaning the dust, insert the fastening cap bolt into the drill hole, tighten the nut, and fix the fastening cap bolt tightly in the drill hole. Then tighten the cap platform on the top of the fastening cap bolt.

[0013] Step 2: Connect one end of the side-attached acceleration sensor to the low-strain detector of the pile foundation, and stick the other end tightly to the side surface of the pile foundation detection point through special plasticine, and the angle between the plane projection of the excitation point and the detection point and the line connecting the pile center should be 90°;

[0014] Step 3: Turn on the foundation pile low strain detector, set the project name, set the pile length, pile diameter and other parameters, and prepare to collect data;

[0015] Step 4. After all the above preparations are completed, click Start Collection and use a low-strain hammer to vertically excite the bolt cap platform. Stop the collection when at least three relatively consistent data waveforms are obtained.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The low-strain detection device for active wharf foundation piles of the present invention uses a fastening cap bolt to be obliquely embedded into the side of the foundation pile to a certain depth, and the cap platform is installed on the top of the fastening cap bolt. A low-strain hammer is used to vertically excite the cap platform, and the kinetic energy of the excitation is transmitted to the foundation pile through the fastening cap bolt, thereby avoiding the existing structure on the top of the foundation pile, achieving the excitation of the active wharf foundation pile, and finally using an acceleration sensor installed on the pile side to receive the signal. Compared with the pile side grooving method recommended in the relevant foundation pile detection specifications (cutting 1-2 grooves on the pile side for excitation and placing sensors), this method only requires drilling a small hole on the pile side, which not only makes the waveform effect collected more accurate and effective, but also significantly reduces the difficulty of construction operations, reduces damage to the foundation piles, improves work efficiency, and reduces the safety risks of operations under the wharf. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional cross-sectional structure of the low-strain detection device for the existing dock foundation piles of the present invention;

[0019] Figure 2 It is a schematic cross-sectional structure diagram of the fastening cap bolt of the excitation assembly of the low-strain detection device for the foundation pile of the current dock of the present invention;

[0020] Figure 3 It is a schematic diagram of the cross-sectional structure of the side-mounted sensor of the low-strain detection device for the existing dock foundation piles of the present invention;

[0021] Figure 4 The cross-sectional structure diagram of the low-strain hammer of the low-strain detection device for the active wharf foundation piles of the present invention is shown in the figure: 1. Active wharf foundation piles; 2. Reference detector body; 3. Data transmission line; 4. Low-strain hammer; 5. Fastening cap bolt; 6. Side-mounted acceleration sensor; 7. Expansion tube; 8. Bolt; 9. Nut; 10. Bolt cap platform. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described below in conjunction with specific implementation methods:

[0023] like Figure 1As shown, a low-strain detection device for active wharf foundation piles comprises a foundation pile low-strain detector body 2, the detector body 2 is connected to a side-attached acceleration sensor via a data transmission line 3; the side-attached acceleration sensor is tightly attached to the side surface of the active wharf foundation pile 1 via special plasticine; a fastening cap bolt 5 has a diameter of 8 mm and a length of 50 mm, and is divided into four parts: an expansion tube, a bolt, a nut, and a cap platform; one end of the fastening cap bolt 5 with the expansion tube is inserted into a borehole, and when the nut is tightened, the internal bolt is pulled outward, the expansion tube is opened, and a friction self-locking is formed between the pile wall, the expansion tube, and the internal bolt, so that the fastening cap bolt 5 is tightly fixed in the pile wall borehole, and the cap platform is fixed It is fixed on the top of the fastening cap bolt 5; the low-strain detection hammer 4 vertically excites the bolt cap platform, receives low-strain reflection data through the side-mounted acceleration sensor, and transmits it to the foundation pile low-strain detector, thereby realizing the low-strain detection of the active dock. Compared with the pile side grooving method recommended in the relevant foundation pile detection specifications (cutting 1-2 grooves on the pile side for excitation and placing sensors), this device only needs to drill a small hole with a diameter of 10mm and a depth of about 40mm on the pile side. Not only is the waveform effect collected more accurate and effective, but it also significantly reduces the difficulty of construction operations, reduces damage to the foundation piles, improves work efficiency, and reduces the safety risks of operations under the dock.

[0024] The cap platform on the top of the fastening cap bolt is vertically excited by a low-strain hammer, which is then transmitted to the existing foundation piles through the fastening cap bolts. Data is collected through the side-mounted acceleration sensor to achieve low-strain detection of the existing wharf foundation piles.

[0025] The fastening cap bolts are implanted on the sides of the existing wharf piles by drilling holes, and the kinetic energy is transmitted to the piles by means of the cap platform of the fastening cap bolts which is vertically excited, so as to carry out low-strain detection on the existing wharf piles.

[0026] Low-strain detection of the existing wharf foundation piles is carried out by drilling holes, implanting fastening cap bolts and side-attached acceleration sensors.

[0027] The fastening cap bolt is removed after the inspection is completed, and the small drilled hole formed is repaired with waterproof and anti-corrosion materials.

[0028] The method for using the low-strain detection device for the existing wharf foundation piles specifically comprises the following steps:

[0029] Step 1: Set an excitation point on the foundation piles that need to be tested for low strain under the active wharf. To facilitate drilling and excitation, the excitation point should be more than 30 cm away from the pile top and the water surface. After the excitation point is determined, use a handheld electric drill to drill a hole with a diameter of 10 mm and a depth of 40 mm at a 45° angle downward at the test point. After cleaning the dust, insert the fastening cap bolt into the drill hole, tighten the nut, and fix the fastening cap bolt tightly in the drill hole. Then tighten the cap platform on the top of the fastening cap bolt.

[0030] Step 2: Connect one end of the side-mounted acceleration sensor to the low-strain detector of the pile foundation, and stick the other end tightly to the side surface of the pile foundation detection point through special plasticine. The angle between the plane projection of the excitation point and the detection point and the line connecting the center of the pile should be 90°.

[0031] Step 3: Turn on the pile foundation low strain detector, set the project name, set the pile length, pile diameter and other parameters, and prepare to collect data;

[0032] Step 4. After all the above preparations are completed, click Start Collection and use a low-strain hammer to vertically vibrate the bolt cap platform. Stop the collection when at least three relatively consistent data waveforms are obtained.

[0033] This embodiment is only a further explanation of the invention rather than a limitation of the invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as they are within the scope of the claims of the invention, they are protected by the patent law.

Claims

1. A low-strain detection device for existing wharf foundation piles, characterized in that: It includes a detector body and an excitation component for the active pile foundation, the detector body is connected to a side-attached acceleration sensor through a data line, the excitation component is arranged on the side surface of the active pile foundation, and the side-attached acceleration sensor is tightly attached to the side surface of the active pile foundation; the excitation component includes a low-strain hammer, a fastening cap bolt and a side-attached acceleration sensor; the fastening cap bolt is fixed obliquely downward on the side surface of the active pile foundation by drilling a hole; the side-attached acceleration sensor is tightly attached to the side surface of the active pile foundation by special plasticine.

2. The low-strain detection device for active wharf foundation piles according to claim 1 is characterized in that: The cap platform on the top of the fastening cap bolt is vertically excited by a low-strain hammer, which is then transmitted to the existing foundation piles through the fastening cap bolts. Data is collected through the side-mounted acceleration sensor to achieve low-strain detection of the existing wharf foundation piles.

3. The low-strain detection device for active wharf foundation piles according to claim 1 is characterized in that: The fastening cap bolts are implanted on the sides of the existing wharf piles by drilling holes, and the kinetic energy is transmitted to the piles by means of the cap platform of the fastening cap bolts which is vertically excited, so as to carry out low-strain detection on the existing wharf piles.

4. The low-strain detection device for active wharf foundation piles according to claim 1 is characterized in that: Low-strain detection of the existing wharf foundation piles is carried out by drilling holes, implanting fastening cap bolts and side-attached acceleration sensors.

5. The low-strain detection device for active wharf foundation piles according to claim 1 is characterized in that: The fastening cap bolt is taken out after the inspection is completed, and the formed drilled hole is repaired by waterproof and anti-corrosion materials.

6. The method for using the low-strain detection device for active wharf foundation piles according to claim 1 is characterized in that: The method comprises the following steps: Step 1: Set an excitation point on the foundation piles that need to be tested for low strain under the active wharf. To facilitate drilling and excitation, the excitation point should be more than 30 cm away from the pile top and the water surface. After the excitation point is determined, use a handheld electric drill to drill a hole with a diameter of 10 mm and a depth of 40 mm at a 45° angle downward at the test point. After cleaning the dust, insert the fastening cap bolt into the drill hole, tighten the nut, and fix the fastening cap bolt tightly in the drill hole. Then tighten the cap platform on the top of the fastening cap bolt. Step 2: Connect one end of the side-attached acceleration sensor to the low-strain detector of the pile foundation, and stick the other end tightly to the side surface of the pile foundation detection point through special plasticine, and the angle between the plane projection of the excitation point and the detection point and the line connecting the pile center should be 90°; Step 3: Turn on the foundation pile low strain detector, set the project name, set the pile length, pile diameter and other parameters, and prepare to collect data; Step 4. After all the above preparations are completed, click Start Collection and use a low-strain hammer to vertically vibrate the bolt cap platform. Stop the collection when at least three relatively consistent data waveforms are obtained.

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