An optical fiber grating adaptive laying device and method for measuring the axial force distribution of a cast-in-place pile

Abstract

The present invention relates to the field of implanting optical fibers in cast-in-place piles, and particularly relates to an optical fiber grating adaptive laying device and method for measuring the axial force distribution of cast-in-place piles. The device includes a holding rod, an arc-shaped rod, and an optical fiber grating transmission assembly. The optical fiber grating transmission assembly includes a radial angle adjusting rod and an optical fiber grating fixing module. The arc-shaped rod is provided with a first rod opening, and one end of the holding rod is connected to the first rod opening. The radial angle adjusting rod is provided with a second rod opening connected to the arc-shaped rod. One end of the radial angle adjusting rod is hinged to the optical fiber grating fixing module, and the other end of the optical fiber grating fixing module is fixed with the optical fiber grating to be installed. After the optical fiber grating fixing module rotates around the hinge position to be parallel to the main reinforcement of the steel reinforcement cage, angle fixing is performed through fasteners. The present invention maximally improves the survival rate of the optical fiber grating and realizes the effective measurement of the axial force distribution of long spiral drilled cast-in-place piles during the static load test of pile foundations.

Description

Technical Field

[0001] The present invention relates to the field of cast-in-place pile optical fiber implantation, and particularly to an optical fiber grating adaptive laying device and method for measuring the axial force distribution of cast-in-place piles. Background Art

[0002] Regarding the technology of cast-in-place pile optical fiber implantation, there are already relevant patented technologies, but there are still some limitations when measuring the axial force distribution characteristics of long spiral drilled cast-in-place piles, which are specifically as follows:

[0003] Patent CN 211876974 U: "An implantation device for optical fiber used in measuring internal force of cast-in-place pile body" includes an optical fiber, a sonic logging tube with cement slurry inside, an optical fiber implantator extending into the sonic logging tube, and a winding mechanism connected to the optical fiber implantator and the optical fiber. Its feature is that the optical fiber is implanted after the construction of the cast-in-place pile. By using a bottom hammer to increase the weight of the optical fiber implantator, the optical fiber can be brought into the sonic logging tube just filled with cement slurry by the self-weight of the optical fiber implantator and the steel wire rope, and the optical fiber can be laid along the entire length of the sonic logging tube to ensure the verticality of the optical fiber, realizing the post-construction optical fiber implantation of the cast-in-place pile, avoiding the cross influence with the construction of the cast-in-place pile, and having a high optical fiber survival rate.

[0004] Patent CN105332393B: "A construction technology of a lateral stiffness monitoring system for long spiral post-inserted cage cast-in-place piles" uses the optical fiber grating sensing technology. During the construction process of post-inserting the cage of long spiral cast-in-place piles, the sensor is fixed on the outer side of the steel cage wall, and the data acquisition port is safely led out above the construction operation surface by using a protective sleeve, so as to measure the stress and strain data of the pile foundation.

[0005] In Patent CN211876974U: "An implantation device for optical fiber used in measuring internal force of cast-in-place pile body", the optical fiber is laid after the construction of the cast-in-place pile. The optical fiber cannot be combined with cement or steel bars, so it cannot deform together during the static load test, affecting the axial force measurement result.

[0006] In Patent CN105332393B: "A construction technology of a lateral stiffness monitoring system for long spiral post-inserted cage cast-in-place piles", the optical fiber sensor is installed on the outer side of the steel cage, making the optical fiber sensor exposed, and it is easy to damage the optical fiber during the construction process, resulting in a low survival rate.

[0007] It should be noted that the steel reinforcement cage of the long - auger cast - in - place pile generally has a diameter of 400 - 800 mm, is provided with multiple longitudinal main bars, and is welded and fixed on the outside by dense spiral stirrups. Among them, one main bar is used for hoisting the overall steel reinforcement cage and has a prominent lifting lug. In addition, one end of the steel reinforcement cage of the long - auger cast - in - place pile is conical and closed, aiming to use a vibrator to insert the steel reinforcement cage into the concrete filled with gravel. Therefore, when measuring the axial force distribution characteristics of the long - auger cast - in - place pile, the fiber Bragg grating should be laid at the intersection of the stirrups and the main bars not used for hoisting, and avoid installing it on the outside of the steel reinforcement cage, so as to protect the safety of the optical fiber during the hoisting and inserting into the concrete process. However, due to the dense stirrups, it is difficult to transfer the optical fiber inside the steel reinforcement cage by hand operation. At the same time, due to the closed end of one end of the steel reinforcement cage and the small diameter of the steel reinforcement cage, it is difficult to install the optical fiber using the traditional method, that is, the worker walks inside the steel reinforcement cage and straightens the optical fiber inside the steel reinforcement cage and then fixes it on the main bar. Therefore, in view of the characteristics of the steel reinforcement cage of the long - auger cast - in - place pile, the present invention aims to propose a more applicable and efficient fiber Bragg grating laying device and its use method to ensure the survival of the fiber Bragg grating and the subsequent measurement of the axial force distribution characteristics of the pile foundation. Summary of the Invention

[0008] The present invention provides a fiber Bragg grating adaptive laying device and method for measuring the axial force distribution of cast - in - place piles, aiming to maximize the survival rate of the fiber Bragg grating, so as to effectively measure the axial force distribution of the long - auger cast - in - place pile during the static load test of the pile foundation.

[0009] The present invention provides a fiber Bragg grating adaptive laying device for measuring the axial force distribution of cast - in - place piles, including a holding rod, an arc - shaped rod, and a fiber Bragg grating transmission component. The fiber Bragg grating transmission component includes a radial angle adjustment rod and an openable and closable fiber Bragg grating fixing module. The arc - shaped rod is provided with a first rod opening, and one end of the holding rod is connected in the first rod opening. After the arc - shaped rod rotates around one end of the holding rod to be parallel to the stirrups of the steel reinforcement cage, it is fixedly connected to the holding rod through a fastener; the radial angle adjustment rod is provided with a second rod opening connected to the arc - shaped rod. After adjusting the position and angle of the radial angle adjustment rod on the arc - shaped rod, it is fixed through a fastener. One end of the radial angle adjustment rod is hinged to one end of the fiber Bragg grating fixing module, and the other end of the fiber Bragg grating fixing module fixes the optical fiber grating to be installed. The fiber Bragg grating fixing module rotates around the hinge position to be parallel to the main bar of the steel reinforcement cage and then is fixed at an angle through a fastener.

[0010] As a further improvement of the present invention, the fiber Bragg grating fixing module includes a first base, a second base, at least three groups of electric doors, and a servo motor. The first base is connected to a radial angle adjusting rod, and the second base fixes the fiber Bragg grating to be installed. A card slot is provided on the second base. One end of the electric door is connected to the first base through the servo motor, and a hook connected to the card slot is provided at the other end of the electric door. The servo motor controls the electric door to flip so that the hook engages or disconnects from the card slot.

[0011] As a further improvement of the present invention, a button is provided on the grip rod, and the button is connected to the servo motor.

[0012] As a further improvement of the present invention, a coil is wound around the electric door, and both ends of the coil are connected to the button. The button controls the energization or de-energization of the coil.

[0013] As a further improvement of the present invention, the fiber Bragg grating adaptive laying device further includes a protective hose and a detachable buckle. The protective hose is tied to the fiber Bragg grating on the bottom stirrup, and the fiber Bragg grating fixing module is connected to the protective hose through the buckle.

[0014] As a further improvement of the present invention, the fiber Bragg grating adaptive laying device further includes a protective rigid pipe. The protective rigid pipe is connected to the main reinforcement and sleeved on the top of the fiber Bragg grating.

[0015] The present invention also provides a fiber Bragg grating adaptive laying method for measuring the axial force distribution of a grouting pile, including the following steps:

[0016] S1. Cut the protective hose and put the protective hose on the middle part of the fiber Bragg grating;

[0017] S2. Fix the fiber Bragg grating with the protective hose on the second base of the fiber Bragg grating transmission component through the buckle;

[0018] S3. Assemble and adjust the fiber Bragg grating adaptive laying device, including the grip rod, the arc-shaped rod, and the fiber Bragg grating transmission component, so that the arc-shaped rod is parallel to the stirrup, and the fiber Bragg grating fixed on the fiber Bragg grating transmission component is parallel to the main reinforcement;

[0019] S4. Move the arc-shaped rod, the fiber Bragg grating transmission component, and the fiber Bragg grating along the axial direction of the steel cage simultaneously through the grip rod, and the fiber Bragg grating transmission component passes through the stirrup;

[0020] S5. Every time it advances a grating pitch, install the buckle to preliminarily connect the fiber Bragg grating to the main reinforcement without fixing it;

[0021] S6. Pull the fiber Bragg grating to the bottom of the steel cage, and fix the fiber Bragg grating section with the protective hose to the bottom stirrup through the buckle;

[0022] S7. Disassemble the fiber Bragg grating adaptive laying device;

[0023] S8. Apply a tensile force to the fiber Bragg grating at the open end of the steel reinforcement cage;

[0024] S9. While maintaining the tensile force, fix the sensor node in the fiber Bragg grating to the main reinforcement through a buckle;

[0025] S10. Place the head and the redundant part of the fiber Bragg grating into a protective hard tube, and fix the protective hard tube to the main reinforcement.

[0026] As a further improvement of the present invention, the step S3 specifically includes:

[0027] S31. Adjust the grip rod to adapt to the user's height;

[0028] S32. Adjust the angle of the arc-shaped rod so that the arc-shaped rod is parallel to the stirrup, and fix it to the grip rod through a fastener;

[0029] S33. Adjust the position of the fiber Bragg grating transmission component by adjusting the angle of the radial angle adjusting rod relative to the arc-shaped rod, so that the fiber Bragg grating transmission component aligns with the position of the main reinforcement where the fiber Bragg grating is to be laid, and fix the radial angle adjusting rod to the arc-shaped rod through a fastener;

[0030] S34. Adjust the angle of the fiber Bragg grating transmission component through the hinge point so that the moving direction of the fiber Bragg grating is consistent with the axial direction of the steel reinforcement cage, and fix the hinge point through a fastener.

[0031] As a further improvement of the present invention, the step S4 includes the following steps:

[0032] S41. Triggered by the button on the grip rod, cut off the power supply of the coil of the first electric door, make the steering gear work to open the first electric door, pull the grip rod to move the fiber Bragg grating and make the stirrup enter between the first electric door and the second electric door, while the second electric door and the third electric door remain connected to the second base;

[0033] S42. Triggered by the button on the grip rod, close the first electric door, and power on the coil of the first electric door, cut off the power supply of the coil of the second electric door, make the steering gear work to open the second electric door, pull the grip rod to move the fiber Bragg grating and make the stirrup enter between the second electric door and the third electric door, while the first electric door and the third electric door remain connected to the second base;

[0034] S43. Triggered by the button on the grip rod, close the second electric door, and power on the coil of the second electric door, cut off the power supply of the coil of the third electric door, make the steering gear work to open the third electric door, pull the grip rod to move the fiber Bragg grating and make the entire fiber Bragg grating transmission component pass through the stirrup, while the first electric door and the second electric door remain connected to the second base.

[0035] As a further improvement of the present invention, the tensile force value F applied to the fiber grating in step S8 op is:

[0036]

[0037] where E p is the modulus of the long spiral bored cast-in-place pile estimated; F p is the maximum vertical load of the pile foundation test estimated; D p is the pile diameter; E op is the fiber grating modulus measured by tensile test before installation; D p is the fiber diameter.

[0038] The beneficial effects of the present invention are: applicable to long spiral bored cast-in-place piles, the fiber grating is installed inside the steel cage and the survival rate is improved; strong engineering adaptability, can be adjusted to adapt to different height users, different pile lengths, different main reinforcement layouts, different stirrup densities and installation angles, and can adapt to different pile diameters by replacing the component sizes. Description of the Drawings

[0039] Figure 1 is a schematic structural diagram of the fiber along the main reinforcement of the long spiral bored cast-in-place pile steel cage arranged symmetrically in a U shape in the present invention;

[0040] Figure 2 is the present invention Figure 1 The sectional view of A-A in;

[0041] Figure 3 is the present invention Figure 1 The sectional view of B-B in;

[0042] Figure 4 is the present invention Figure 1 The sectional view of C-C in;

[0043] Figure 5 is the structural diagram of the fiber grating adaptive laying device in the present invention;

[0044] Figure 6 is the structural diagram of the fiber grating transmission component in the present invention;

[0045] Figure 7 is the schematic structural diagram of the first step of the fiber grating transmission component passing through the stirrup in the present invention;

[0046] Figure 8 is the schematic structural diagram of the second step of the fiber grating transmission component passing through the stirrup in the present invention;

[0047] Figure 9 is the schematic structural diagram of the third step of the fiber grating transmission component passing through the stirrup in the present invention. Specific Embodiments

[0048] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0049] Compared with traditional slurry-supported piles, long spiral drilled cast-in-place piles do not use slurry, and have the advantages of being environmentally friendly and having higher bearing capacity under the same pile length. Therefore, they are becoming increasingly popular in engineering.

[0050] The present invention is used to lay the fiber Bragg grating 2 for measuring the axial force distribution characteristics in the long spiral drilled cast-in-place pile, and is mainly proposed in view of the characteristics and problems of the steel cage 1 of the long spiral drilled cast-in-place pile, that is, the distance between the steel bars is dense and one end of the steel cage 1 is closed, resulting in the problem that the fiber Bragg grating 2 cannot be simply laid quickly by hand. For this reason, the present invention aims to propose a device and its use method suitable for laying the fiber Bragg grating 2 in the long spiral drilled cast-in-place pile, to maximize the survival rate of the fiber Bragg grating 2, so as to effectively measure the axial force distribution of the long spiral drilled cast-in-place pile during the static load test of the pile foundation.

[0051] Embodiment 1:

[0052] As Figures 1 to 5 shown, an adaptive laying device for fiber Bragg grating for measuring the axial force distribution of a cast-in-place pile of the present invention includes a grip rod 3, an arc-shaped rod 4, and a fiber Bragg grating transmission assembly. The fiber Bragg grating transmission assembly includes a radial angle adjustment rod 5 and an openable and closable fiber Bragg grating fixing module 6. The arc-shaped rod 4 is provided with a first rod opening 41. One end of the grip rod 3 is connected in the first rod opening 41. After the arc-shaped rod 4 rotates around one end of the grip rod 3 to be parallel to the stirrup 12 of the steel cage 1, it is fixedly connected to the grip rod 3 through a fastener; the radial angle adjustment rod 5 is provided with a second rod opening 51 connected to the arc-shaped rod 4. After the radial angle adjustment rod 5 adjusts its position and angle on the arc-shaped rod 4, it is fixed through a fastener. One end of the radial angle adjustment rod 5 is hinged to one end of the fiber Bragg grating fixing module 6, and the other end of the fiber Bragg grating fixing module 6 is fixed to the fiber Bragg grating 2 to be installed. The fiber Bragg grating fixing module 6 rotates around the hinge position to be parallel to the main reinforcement 11 of the steel cage 1 and then is fixed at an angle through a fastener.

[0053] From Figure 1 it can be seen that the steel cage 1 of the long spiral drilled cast-in-place pile is provided with multiple vertical main reinforcements 11 and is fixedly welded on the outside by dense spiral stirrups 12 (the spacing is only 100-200 mm). At the same time, one end of the steel cage 1 of the long spiral drilled cast-in-place pile is conical and closed. The fiber Bragg grating 2 is laid at the intersection of the stirrup 12 and the main reinforcement 11 that is not used for lifting, in a U shape, to improve the success rate of measuring the axial force distribution characteristics of the pile foundation: that is, when one side of the fiber Bragg grating 2 is damaged during the pile foundation construction, the fiber Bragg grating 2 on the other side can still be used for measurement.

[0054] The laying of the fiber Bragg grating 2 often takes place after the welding of the steel reinforcement cage 1 is completed, because the welding process is extremely likely to damage the fiber Bragg grating 2. For the steel reinforcement cage 1 of the long spiral drilled and pressure-grouted pile, firstly, due to the dense steel bars, it is difficult to pass the fiber Bragg grating 2 inside the steel reinforcement cage 1 by manual operation. Secondly, since one end is closed and the diameter of the steel reinforcement cage 1 is small, it is difficult to walk inside the steel reinforcement cage 1 and straighten the fiber Bragg grating 2 at both ends of the steel reinforcement cage 1 and then fix it on the main steel bars 11. Therefore, a device as shown in Figure 2 is proposed to realize the adaptive laying of the fiber Bragg grating 2 for measuring the axial force distribution of the long spiral drilled and pressure-grouted pile. To reduce the weight of the device and improve its ease of use, most of the device is made of aluminum alloy.

[0055] Among them, the fiber Bragg grating 2: Without loss of generality, to reduce the damage of the gravel in the concrete to the fiber Bragg grating 2, a fiber Bragg grating 2 with a diameter of less than 5 mm is used; the spacing of the fiber Bragg grating 2 is 0.5 m - 1.0 m, which is similar to the common formation thickness. Therefore, the axial force value of the long spiral drilled and pressure-grouted pile in each layer of soil can be measured; the modulus of the fiber Bragg grating 2 is obtained as E through the tensile test op .

[0056] The holding rod 3 is divided into a vertical rod and a horizontal rod. The vertical rod is provided with threads and is equipped with an axial angle fixing nut 31. The diameter of the vertical rod part is smaller than the aperture of the first rod opening 41 of the arc-shaped rod 4 and can be inserted into the arc-shaped rod 4. The horizontal rod is provided with a button to control the opening and closing of the electric door 63 in the fiber Bragg grating transmission component.

[0057] The arc-shaped rod 4 can rotate around the vertical rod part of the holding rod 3 to change its angle with the axis of the steel reinforcement cage 1, make its direction parallel to the stirrup 12, and fix this angle through the axial angle fixing nut 31.

[0058] The fiber Bragg grating transmission component is inserted into the arc-shaped rod 4 through the second rod opening 51 in the radial angle adjusting rod 5, and the angle between the fiber Bragg grating fixing module 6 and the radial direction of the steel reinforcement cage 1 can be adjusted, so as to determine the main steel bar 11 to which the fiber Bragg grating 2 is bound. And since the radial angle adjusting rod 5 is provided with threads, the radial angle fixing nut 52 is used to fix the radial angle adjusting rod 5 on the arc-shaped rod 4 to fix this angle.

[0059] The radial angle adjusting rod 5 and the first base 61 of the fiber Bragg grating fixing module 6 are connected by a spherical hinge 7. The angle of the fiber Bragg grating fixing module 6 is adjusted through the spherical hinge 7 to make the advancing direction of the fiber Bragg grating 2 parallel to the direction of the main steel bar 11, and the angle is adjusted and fixed by the spherical hinge fixing nut 71 fixed on the spherical hinge 7.

[0060] As shown in Figure 6As shown in the figure, the fiber grating fixing module 6 includes a first base 61, a second base 62, at least three groups of electric doors 63, and a servo 64. The first base 61 is connected to the radial angle adjusting rod 5, and the second base 62 fixes the fiber grating 2 to be installed. A card slot 621 is provided on the second base 62. One end of the electric door 63 is connected to the first base 61 through the servo 64, and a hook 634 connected to the card slot 621 is provided at the other end of the electric door 63. The servo 64 controls the electric door 63 to flip so that the hook 634 engages or disconnects from the card slot 621.

[0061] As Figure 5 and 6 shown in the figure, a button is provided on the grip rod 3, and the button is connected to the servo 64. A coil is wound around the electric door 63, and both ends of the coil are connected to the button. The button controls the energization or de-energization of the coil. One end of the button is connected to the servo 64 and the coil, and the other end is connected to the power supply. The power supply to the corresponding servo 64 and coil is controlled by the switch of the button, so as to specifically control the closing or opening of the corresponding electric door 63.

[0062] In this embodiment, the electric doors 63 are divided into a first electric door 631, a second electric door 632, and a third electric door 633. The servo 64 is controlled by the button on the grip rod 3 to control the opening and closing of the electric door 63. The second base 62 is used for binding the fiber grating 2 and is made of hollow steel. The card slot 621 is provided to facilitate the engagement of the electric door 63 with the second base 62. Electromagnets are formed by winding coils around the first electric door 631 to the third electric door 633. After closing, they are energized to enhance the firmness of the engagement with the second base 62. Before opening, the power is cut off first to make it easier for the servo 64 to open the electric door 63. At least three electric doors 63 are used to fix the second base 62, so as to ensure that at least two electric doors 63 are connected to the second base 62 when passing through the stirrup 12, thereby positioning the movement direction of the fiber grating 2 without deviation.

[0063] As Figures 1 to 6 shown in the figure, the fiber grating adaptive laying device further includes a protective hose 21 and a detachable buckle 8. The protective hose 21 is tied to the fiber grating 2 on the bottom stirrup 12, and the fiber grating fixing module 6 is connected to the protective hose 21 through the buckle 8. The protective hose 21 is preferably a PVC protective hose 21, and its inner diameter is larger than that of the fiber grating 2, which is used to protect the fiber grating 2 tied to the bottom stirrup 12.

[0064] As Figure 1 and 2As shown, the fiber grating adaptive laying device further includes a protective rigid tube 22. The protective rigid tube 22 is connected to the main reinforcement 11 and sleeved on the top of the fiber grating 2. The protective rigid tube 22 is preferably a galvanized copper tube. The inner diameter of the galvanized copper tube is larger than that of the fiber grating 2. It is fixed on the main reinforcement 11 to prevent damage to the fiber head (for connecting the fiber grating 2 demodulator) during the hoisting, insertion of the steel cage 1 and the construction of the pile cap.

[0065] Embodiment 2:

[0066] A fiber grating 2 adaptive laying method for measuring the axial force distribution of a grouted pile of the present invention includes the following steps:

[0067] S1. Cut a PVC protective hose 21 with a length greater than half of the interface circumference of the steel cage 1, and sleeve the PVC protective hose 21 onto the middle of the fiber grating 2.

[0068] S2. Fix the fiber grating 2 with the PVC protective hose 21 to the second base 62 of the fiber grating transmission assembly through a detachable buckle 8, as Figure 5 shown.

[0069] S3. Assemble and adjust the fiber grating adaptive laying device, including the grip rod 3, the arc-shaped rod 4, and the fiber grating transmission assembly, so that the arc-shaped rod 4 is parallel to the stirrup 12, and the fiber grating 2 fixed on the fiber grating transmission assembly is parallel to the main reinforcement 11; specifically:

[0070] S31. Adjust the grip rod 3 to adapt to the user's height;

[0071] S32. Adjust the angle of the arc-shaped rod 4 to adapt to the arrangement of the stirrup 12, make the arc-shaped rod 4 parallel to the stirrup 12, and fix it to the grip rod 3 through the axial angle fixing nut 31;

[0072] S33. Adjust the position of the fiber grating transmission assembly by adjusting the angle of the radial angle adjusting rod 5 relative to the arc-shaped rod 4, so that the fiber grating transmission assembly adapts to and aligns with the position of the main reinforcement 11 where the fiber grating 2 is to be laid, and fix the radial angle adjusting rod 5 to the arc-shaped rod 4 through the radial angle fixing nut 52;

[0073] S34. Adjust the angle of the fiber grating transmission assembly through the ball joint 7, make the moving direction of the fiber grating 2 consistent with the axial direction of the steel cage 1, and fix the ball joint 7 through the ball joint 7 fixing nut 71 to fix this adjusted angle.

[0074] S4. Move the entire device forward along the axial direction of the steel cage 1 through the grip rod 3, including the arc-shaped rod 4, the fiber grating transmission assembly, and the fiber grating 2 moving simultaneously, and the fiber grating transmission assembly passes through the stirrup 12; the specific passing process includes the following steps:

[0075] S41. As shown in Figure 7 it, by triggering the button on the grip rod 3, the coil of the first electric door 631 is powered off, the steering gear 64 works to open the first electric door 631, the grip rod 3 is pulled to move the fiber grating 2 and the stirrup 12 enters between the first electric door 631 and the second electric door 632. At the same time, the second electric door 632 and the third electric door 633 remain connected to the second base 62. At this time, since there are two electric doors 63 connected to the second base 62, the entire fiber grating transmission assembly can still maintain a good balance and stable state.

[0076] S42. As shown in Figure 8 it, by triggering the button on the grip rod 3, the first electric door 631 is closed, and the coil of the first electric door 631 is powered on to make it bite more tightly with the second base 62. The coil of the second electric door 632 is powered off, the steering gear 64 works to open the second electric door 632, the grip rod 3 is pulled to move the fiber grating 2 and the stirrup 12 enters between the second electric door 632 and the third electric door 633. At the same time, the first electric door 631 and the third electric door 633 remain connected to the second base 62;

[0077] S43. As shown in Figure 9 it, by triggering the button on the grip rod 3, the second electric door 632 is closed, and the coil of the second electric door 632 is powered on to make it bite more tightly with the second base 62. The coil of the third electric door 633 is powered off, the steering gear 64 works to open the third electric door 633, the grip rod 3 is pulled to move the fiber grating 2 and the entire fiber grating transmission assembly passes through the stirrup 12 smoothly. At the same time, the first electric door 631 and the second electric door 632 remain connected to the second base 62.

[0078] S5. For each advancement of a grating pitch (0.5 - 1.0 m), install the detachable buckle 8 to preliminarily connect the fiber grating 2 to the main reinforcement 11 without fixation.

[0079] S6. The fiber grating 2 is pulled to the bottom of the steel reinforcement cage 1 (excluding the conical part). As shown in Figure 1 it, the section of the fiber grating 2 with the PVC protection hose 21 is fixed to the bottom stirrup 12 through the detachable buckle 8.

[0080] S7. Dismantle the fiber grating adaptive laying device.

[0081] S8. Apply a tensile force to the fiber grating 2 at the open end of the steel reinforcement cage 1: Estimate the modulus of the long - auger bored cast - in - place pile (i.e., reinforced concrete pile) as E p , estimate the maximum vertical load of the pile foundation test as F p , and the pile diameter as D p . Before installation, the modulus of the fiber grating 2 has been measured as E op through a tensile test, and the fiber diameter is Dp To ensure that the fiber Bragg grating 2 is always in a tensile state during the test, a tensile force F is applied to the fiber Bragg grating 2 at the open end of the steel reinforcement cage 1 op :

[0082]

[0083] S9. Under the action of the tensile force, the sensor node in the fiber Bragg grating 2 is fixed to the main reinforcement 11 through the detachable buckle 8, and the position where the stirrup 12 intersects with the main reinforcement 11 is preferably selected to ensure the survival rate of the optical fiber.

[0084] S10. The head and the redundant part of the fiber Bragg grating 2 are placed into the galvanized copper tube, and the galvanized copper tube is fixed to the main reinforcement 11, so as to prevent damage to the head of the optical fiber (used to connect the fiber Bragg grating 2 demodulator) during the hoisting, insertion of the steel reinforcement cage 1 and the construction of the pile cap, and ensure that the axial force distribution characteristics can be measured during the later pile foundation test.

[0085] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. An optical fiber grating adaptive laying device for measuring the axial force distribution of grouting piles, characterized in that, It includes a grip rod, an arc-shaped rod, and a fiber Bragg grating transmission component. The fiber Bragg grating transmission component includes a radial angle adjustment rod and an openable and closable fiber Bragg grating fixing module. The arc-shaped rod is provided with a first rod opening, and one end of the grip rod is connected in the first rod opening. After the arc-shaped rod rotates around one end of the grip rod to be parallel to the stirrups of the steel reinforcement cage, it is fixedly connected to the grip rod through a fastener; the radial angle adjustment rod is provided with a second rod opening connected to the arc-shaped rod. After adjusting the position and angle of the radial angle adjustment rod on the arc-shaped rod, it is fixed through a fastener. One end of the radial angle adjustment rod is hinged to one end of the fiber Bragg grating fixing module, and the other end of the fiber Bragg grating fixing module fixes the fiber Bragg grating to be installed. After the fiber Bragg grating fixing module rotates around the hinge position to be parallel to the main reinforcement of the steel reinforcement cage, it is angle-fixed through a fastener; The fiber Bragg grating fixing module includes a first base, a second base, at least three groups of electric doors, and a servo motor. The first base is connected to the radial angle adjustment rod, and the second base fixes the fiber Bragg grating to be installed. A card slot is provided on the second base. One end of the electric door is connected to the first base through a servo motor, and a hook connected to the card slot is provided at the other end of the electric door. The servo motor controls the electric door to flip so that the hook engages or disconnects from the card slot; It further includes a protective hose and a detachable buckle. The protective hose is tied to the fiber Bragg grating on the bottom stirrups, and the fiber Bragg grating fixing module is connected to the protective hose through the buckle.

2. The fiber grating adaptive laying device for measuring the axial force distribution of the grouting pile according to claim 1, wherein A button is provided on the grip rod, and the button is connected to the servo motor.

3. The fiber Bragg grating adaptive laying device for measuring the axial force distribution of the grouting pile according to claim 2, wherein, A coil is wound around the electric door, and both ends of the coil are connected to the button. The button controls the energization or de-energization of the coil.

4. The fiber grating adaptive laying device for measuring the axial force distribution of the grouting pile according to claim 1, wherein It further includes a protective rigid tube, and the protective rigid tube is connected to the main reinforcement and sleeved on the top of the fiber Bragg grating.

5. A fiber Bragg grating adaptive laying method for measuring the axial force distribution of a grouted pile, which is implemented based on the fiber Bragg grating adaptive laying device for measuring the axial force distribution of a grouted pile described in claim 1, is characterized in that, It includes the following steps: S1. Cut the protective hose and put the protective hose into the middle of the fiber Bragg grating; S2. Fix the fiber Bragg grating with the protective hose on the second base of the fiber Bragg grating transmission component through a buckle; S3. Assemble and adjust the fiber Bragg grating adaptive laying device, including a grip rod, an arc-shaped rod, and a fiber Bragg grating transmission component, so that the arc-shaped rod is parallel to the stirrups, and the fiber Bragg grating fixed on the fiber Bragg grating transmission component is parallel to the main reinforcement; S4. Move the arc-shaped rod, the fiber Bragg grating transmission component, and the fiber Bragg grating along the axial direction of the steel reinforcement cage simultaneously through the grip rod, and the fiber Bragg grating transmission component passes through the stirrups; S5. Every time it advances a grating pitch, install a buckle to preliminarily connect the fiber Bragg grating to the main reinforcement without fixing it; S6. Pull the fiber Bragg grating to the bottom of the steel reinforcement cage, and fix the fiber Bragg grating section with the protective hose to the bottom stirrups through a buckle; S7. Disassemble the fiber Bragg grating adaptive laying device; S8. Apply a pulling force to the fiber Bragg grating at the opening end of the steel reinforcement cage; S9. Under the action of the pulling force, fix the sensor nodes in the fiber Bragg grating to the main reinforcement through a buckle; S10. Put the head and the redundant part of the fiber Bragg grating into the protective rigid tube, and fix the protective rigid tube to the main reinforcement.

6. The fiber grating adaptive laying method for measuring the axial force distribution of the grouting pile according to claim 5, characterized in that, The specific content of step S3 includes: S31. Adjust the grip rod to adapt to the height of the user; S32. Adjust the angle of the arc-shaped rod so that the arc-shaped rod is parallel to the stirrup, and fix it to the holding rod through fasteners; S33. Adjust the angle of the radial angle adjustment rod relative to the arc-shaped rod to adjust the position of the fiber Bragg grating transmission component, so that the fiber Bragg grating transmission component aligns with the main reinforcement position where the fiber Bragg grating is selected to be laid, and fix the radial angle adjustment rod to the arc-shaped rod through fasteners; S34. Adjust the angle of the fiber Bragg grating transmission component through the hinge point, so that the moving direction of the fiber Bragg grating is consistent with the axial direction of the steel cage, and fix the hinge point through fasteners.

7. The fiber grating adaptive laying method for measuring the axial force distribution of the cast-in-place pile according to claim 5, wherein The step S4 includes the following steps: S41. Triggered by the button on the holding rod, cut off the power supply of the coil of the first electric door, make the servo work to open the first electric door, pull the holding rod to move the fiber Bragg grating and make the stirrup enter between the first electric door and the second electric door. At the same time, the second electric door and the third electric door remain connected to the second base; S42. Triggered by the button on the holding rod, close the first electric door, energize the coil of the first electric door, cut off the power supply of the coil of the second electric door, make the servo work to open the second electric door, pull the holding rod to move the fiber Bragg grating and make the stirrup enter between the second electric door and the third electric door. At the same time, the first electric door and the third electric door remain connected to the second base; S43. Triggered by the button on the holding rod, close the second electric door, energize the coil of the second electric door, cut off the power supply of the coil of the third electric door, make the servo work to open the third electric door, pull the holding rod to move the fiber Bragg grating and make the entire fiber Bragg grating transmission component pass through the stirrup. At the same time, the first electric door and the second electric door remain connected to the second base.

8. The fiber Bragg grating adaptive laying method for measuring the axial force distribution of the cast-in-place pile according to claim 5, characterized in that The tensile force value applied to the fiber grating in step S8 F op is as follows: ， Among them E p is for estimating the modulus of long spiral drilled cast-in-place piles; F p is for estimating the maximum vertical load of pile foundation tests; D p is the pile diameter; E op is the fiber Bragg grating modulus measured by tensile test before installation; D p is the fiber diameter.

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