A combined range-adjustable optical fiber multi-point delamination instrument and measurement method

Abstract

The present invention discloses a combined range-adjustable optical fiber multi-point delamination instrument and a measuring method, which belongs to the technical field of mine safety monitoring. The structure includes a delamination instrument sensor, a mounting part and an adjusting part. The delamination instrument sensor includes a substrate, a wire rope through hole is arranged at the center of the substrate, a cantilever beam is arranged around the wire rope through hole, and a fiber grating is arranged on the cantilever beam; an inner core is also arranged on the substrate, a guide rod is movably arranged in the through hole on the inner core, and the guide rod is pressed against the force point of the cantilever beam after passing through the through hole, and a wire rope is fixed on the other end of the guide rod; one end of the mounting part is arranged on the substrate, and a sleeve is arranged at the other end, and the wire rope extends from the sleeve; the adjusting part includes a spring, one end of the spring is connected to a spring fixing hook, and the other end is connected to the wire rope through a stretching piston, and the spring fixing hook is connected to an anchor claw. The technical solution of the example of the present invention can realize delamination monitoring of three points or more, and provides a technical means for monitoring the safety status of complex roofs.

Description

Technical Field

[0001] The invention relates to the technical field of mine safety monitoring, and in particular to an optical fiber delamination instrument, specifically a combined range-adjustable optical fiber multi-point delamination instrument and a measuring method. Background Art

[0002] The roof of a coal mine is a typical layered structure. When mining coal seams underground, the balance of the rock mass around the working face is destroyed. As the working face continues to advance, the roof loses support and sinks to varying degrees. The amount of sinking determines the safety of the roof. The displacement monitoring of the old roof and the direct roof is a necessary technical means to determine the safety of the roof. When encountering complex roofs such as thick roofs, fragile roofs, or soft rock, relying solely on two monitoring points cannot meet the needs of tunnel safety monitoring. Multi-point separation sensors are required to carefully observe the safety of the roof.

[0003] At present, electronic sensing devices are mostly used for roof safety monitoring. Due to electromagnetic interference on the working surface, inaccurate measurements are easily caused. The existing fiber grating abscission sensor uses optical signals as the measurement and transmission medium, which is resistant to electromagnetic interference, has high accuracy and is inherently safe. However, the fiber grating abscission sensor is limited by complex precision guide rails, gears and other structures, and can only produce fiber optic abscission sensors that monitor two points. It is not possible to make a fiber optic multi-point abscission sensor with more than three points. Summary of the invention

[0004] In order to solve the deficiencies in the above-mentioned prior art, the purpose of the present invention is to provide a combined range-adjustable optical fiber multi-point delamination instrument and measurement method to achieve delamination monitoring of three points or more, providing a technical means for monitoring the safety status of complex roofs.

[0005] The technical solution adopted by the present invention to solve the technical problem is:

[0006] On the one hand, the present invention provides a combined range-adjustable optical fiber multi-point delamination instrument, comprising:

[0007] A delamination instrument sensor, the delamination instrument sensor comprises a substrate, at least three cantilever beam fixing positions are arranged on the substrate, the cantilever beam fixing positions are distributed on the same circumference around the center of the substrate, and a plurality of wire rope through holes are arranged at the center of the substrate; a cantilever beam is fixedly installed at the cantilever beam fixing position, a first optical fiber grating is arranged on the upper side of the cantilever beam, and a second optical fiber grating is arranged on the lower side of the cantilever beam; an inner core is also fixedly installed on the substrate, a plurality of through holes are arranged on the inner core, and the through holes are concentric with the end face of the cantilever beam; a guide rod is movably arranged in the through hole, one end of the guide rod passes through the through hole and presses against the force point of the cantilever beam, and one or more threaded holes are arranged at the other end of the guide rod; a wire rope is fixed in the threaded hole, and the wire rope passes through the cantilever beam and the substrate and extends to the other side of the substrate;

[0008] A mounting member, one end of which is mounted on the base plate, and the other end of which is provided with a sleeve, an outer wall of which is provided with a claw hook, and the steel wire rope passes through the sleeve and extends out from the end of the sleeve;

[0009] The adjusting member comprises a spring, one end of the spring is connected to a spring fixing hook, and the other end of the spring is connected to a stretching piston; the other side of the stretching piston is connected to the steel wire rope, and the other side of the spring fixing hook is connected to an anchor claw.

[0010] Furthermore, a protective shell is provided on the substrate of the delamination meter sensor, and the protective shell includes a cylinder and a rear cylinder. One end of the cylinder is connected to the substrate, and the other end of the cylinder is provided with a rear cover. The rear cylinder is installed on the rear cover and is connected to the cylinder, and the diameter of the rear cylinder is smaller than that of the cylinder; the protective shell covers the cantilever beam, the inner core and the guide rod.

[0011] Furthermore, the spring and the stretching piston are both located in a spring sleeve, the stretching piston can move along the spring sleeve, and the spring fixing hook is fixedly mounted on one end of the spring sleeve.

[0012] Furthermore, a sealing and waterproof structure is provided at the penetration hole of the steel wire rope.

[0013] Furthermore, the rear cover is provided with a sealing ring installation groove and an optical cable waterproof connector for fixing the optical cable.

[0014] Furthermore, the matching portion between the rear tube and the rear cover is connected via threads, and a sealing ring is provided at the connection portion.

[0015] Furthermore, the components of the delamination instrument sensor, the mounting part and the adjusting part are all treated with waterproof sealing.

[0016] On the other hand, the present invention also provides a measurement method of the above-mentioned combined range-adjustable optical fiber multi-point delamination instrument, comprising:

[0017] Install the combined range-adjustable optical fiber multi-point delamination instrument on the structure to be measured;

[0018] After the measured structure is deformed, the anchor claw is pulled, causing the tension piston to extend the traction spring. The extension of the spring is the displacement that the delamination instrument sensor needs to measure.

[0019] The elastic force generated by the extension of the spring is transmitted to the cantilever beam through the wire rope and the guide rod;

[0020] The flexural strain of the cantilever beam is characterized by the wavelength change of the first grating fiber and the second grating fiber;

[0021] Obtain the deformation of the measured structure according to the flexural strain of the cantilever beam;

[0022] The calibration formula of the displacement x, the flexural strain, and the fiber grating wavelength change is:

[0023]

[0024]

[0025] In the above formula:

[0026] ε M is the flexural strain,

[0027] λ B is the central wavelength of the fiber Bragg grating,

[0028] k is the elastic modulus,

[0029] E is the elastic modulus of the cantilever beam,

[0030] h is the thickness of the cantilever beam,

[0031] l is the length of the cantilever beam,

[0032] B is the width of the cantilever beam,

[0033] Δλ B1 is the change in the central wavelength of the first fiber Bragg grating,

[0034] Δλ B2 is the change in the central wavelength of the second fiber Bragg grating.

[0035] Furthermore, the combined range-adjustable optical fiber multi-point delamination instrument is installed on the structure to be measured, comprising:

[0036] S1: drilling mounting holes on the roof of the coal mine that are compatible with mounting parts and adjusting parts of the combined range-adjustable optical fiber multi-point delamination instrument;

[0037] S2: Insert the wire rope and the spring sleeve of the adjusting piece into the hollow mounting rod, expose the anchor claw at the top of the mounting rod, insert the mounting rod into the mounting hole, and push the anchor claw into the old top position of the coal mine roof;

[0038] S3: Pull out the mounting rod and gently pull the wire rope to ensure that the anchor claw is stuck in the mounting hole;

[0039] S4: Repeat S2 and S3 to place N sets of adjustment parts and steel wire rope assemblies into the installation holes, where N is a natural number greater than 1;

[0040] S5: inserting the plurality of steel wire ropes in the above steps into the sleeve of the mounting member, and inserting the mounting member into the mounting hole to fix it;

[0041] S6: Pass the steel wire rope through the steel wire rope through-hole on the base plate and the threaded hole on the guide rod in sequence;

[0042] S7: Fixing the base plate and the mounting member together;

[0043] S8: Stretch the steel wire ropes and the springs of the adjusting parts in sequence according to the installation order, so that all the steel wire ropes are fixedly connected to the corresponding guide rods;

[0044] S9: Cut off the excess part of the wire rope, install the protective shell of the delamination meter sensor, and complete the installation of the combined range-adjustable optical fiber multi-point delamination meter.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The combined range-adjustable optical fiber multi-point delamination instrument of the present invention does not require complex structures such as precision guide rails and gears, has a simple structure and is impact-resistant, adopts the optical fiber Bragg grating sensing principle, and both monitoring and transmission are optical signals. It does not require power supply and is inherently safe, eliminating safety hazards when used in flammable and explosive environments. It is very suitable for roof safety monitoring in complex and harsh environments in coal mines.

[0047] 2. The combined range-adjustable optical fiber multi-point delamination instrument of the present invention does not require a measuring circuit, has a simpler structure, is easy to install, saves costs, has high reliability, does not consume electricity, and can perform continuous measurements.

[0048] 3. The combined range-adjustable optical fiber multi-point delamination instrument exemplified in the present invention can achieve different measuring points by only increasing or decreasing the number of cantilever beams, under the premise that the delamination instrument sensor parameters remain unchanged. The sensor range can be changed by adjusting the length, wire diameter and number of turns of the spring casing and the spring. It has the ability to monitor delamination at more than three points, is suitable for monitoring the internal delamination conditions of complex roofs, and provides detailed data for roof management.

[0049] 4. For the combined range-adjustable optical fiber multi-point delamination meter of the present invention, when different application requirements arise, the sensor part of the delamination meter does not need to be changed, and only the external adjustment part needs to be changed, which facilitates the mass production of the delamination meter sensor and reduces inventory pressure.

[0050] 5. The combined range-adjustable optical fiber multi-point delamination meter of the present invention is provided with a protective housing, mounting parts, spring sleeves, etc., which provide comprehensive and effective protection for the core components and ensure the reliability and service life of the use; the movement of the internal wire rope of the delamination meter sensor part is less than 1 mm, and a sealing and waterproof structure is provided in the wire rope perforation of the substrate, which is superior to the structural design of other optical fiber delamination sensors in the prior art and prevents the corrosion of the sensor by the top plate water.

[0051] 6. The combined range-adjustable optical fiber multi-point delamination instrument of the present invention has a combined structure between the delamination instrument sensor and the mounting parts and the adjusting parts, and the sensing part has good sealing performance and can be reused. When it needs to be reused, it is only necessary to separate the sensing part from the mounting part and cut the wire rope, thereby reducing the user's investment cost.

[0052] 7. The measurement method of the example of the present invention utilizes the linear and one-to-one correspondence between the wavelength change of the fiber grating and the flexural strain. When the cantilever beam parameters and the spring parameters are fixed values, the wavelength change of the fiber grating and the spring elongation are linear and one-to-one corresponding. The deformation of the measured structure is obtained through calculation. The data has a scientific basis and high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0054] Figure 1 It is a schematic diagram of the overall structure of a combined range-adjustable optical fiber multi-point delamination instrument according to an embodiment of the present invention;

[0055] Figure 2 It is a structural schematic diagram of a base plate in a combined range-adjustable optical fiber multi-point delamination instrument according to an embodiment of the present invention;

[0056] Figure 3 It is a schematic diagram of the structure of the inner core in the combined range-adjustable optical fiber multi-point delamination instrument according to an embodiment of the present invention;

[0057] Figure 4 It is a schematic diagram of the structure of the guide rod in the combined range-adjustable optical fiber multi-point delamination instrument according to an embodiment of the present invention;

[0058] Figure 5 It is a schematic diagram of the installation of a combined range-adjustable optical fiber multi-point delamination instrument in the measurement method of an embodiment of the present invention.

[0059] In the figure: 1 base plate, 2 cylinder, 3 inner core, 4 guide rod, 5 rear cylinder, 6 rear cover, 7 cantilever beam, 8 mounting part, 9 wire rope, 91 first wire rope, 92 second wire rope, 93 third wire rope, 10 spring sleeve, 11 stretching piston, 12 spring fixing hook, 13 spring, 14 anchor claw, 141 first anchor claw, 142 second anchor claw, 143 third anchor claw, 15 sleeve, 16 delamination meter sensor, 17 tail cable, 18 mounting hole, 19 old top, 20 direct top. DETAILED DESCRIPTION

[0060] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0061] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0062] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0063] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0064] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0065] 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. It should also be noted that, for ease of description, only the parts related to the invention are shown in the drawings.

[0066] like Figure 1 As shown, one embodiment of the present invention provides a combined range-adjustable optical fiber multi-point delamination instrument, comprising:

[0067] The delamination sensor comprises a substrate 1, the structure of which is as follows: Figure 2 As shown, at least three cantilever beam fixing positions are arranged on the substrate 1, and the cantilever beam fixing positions are distributed on the same circumference around the center of the substrate 1, and a plurality of wire rope through holes are arranged at the center of the substrate 1; a cantilever beam 7 is fixedly installed at the cantilever beam fixing position, a first optical fiber Bragg grating is arranged on the upper side of the cantilever beam 7, and a second optical fiber Bragg grating is arranged on the lower side of the cantilever beam 7; an inner core 3 is also fixedly installed on the substrate 1, and the structure of the inner core 3 is as shown in FIG. Figure 3 As shown, the inner core 3 is provided with a plurality of through holes, and the through holes are concentric with the end surface of the cantilever beam 7; a guide rod 4 is movably provided in the through hole, and the structure of the guide rod 4 is as shown in Figure 4 As shown, one end of the guide rod 4 passes through the through hole and presses against the force point of the cantilever beam 7, and the other end of the guide rod 4 is provided with one or more threaded holes; specifically, two threaded holes are provided on the guide rod 4 of this embodiment, and a steel wire rope 9 is fixed in the threaded holes, and the steel wire rope 9 passes through the cantilever beam 7 and the base plate 1 and extends to the other side of the base plate 1;

[0068] A mounting member 8, one end of which is mounted on the base plate 1, and the other end of which is provided with a sleeve 15, an outer wall of which is provided with a claw hook, and the steel wire rope 9 passes through the sleeve 15 and extends out from the end of the sleeve 15;

[0069] The adjusting member includes a spring 13, one end of the spring 13 is connected to the spring fixing hook 12, and the other end of the spring 13 is connected to the stretching piston 11; the other side of the stretching piston 11 is connected to the wire rope 9, and the other side of the spring fixing hook 12 is connected to the anchor claw 14.

[0070] The claw hook and the anchor claw 14 are both curved claw-like structures.

[0071] In order to protect important components, a protective shell is provided on the substrate 1 of the delamination meter sensor, and the protective shell includes a cylinder 2 and a rear cylinder 5. One end of the cylinder 2 is connected to the substrate 1, and the other end of the cylinder 2 is provided with a rear cover 6. The rear cylinder 5 is installed on the rear cover 6 and is connected to the cylinder 2. The diameter of the rear cylinder 5 is smaller than that of the cylinder 2; the protective shell covers the cantilever beam 7, the inner core 3 and the guide rod 4.

[0072] The spring 13 and the stretching piston 11 are both located in the spring sleeve 10 . The stretching piston 11 can move along the spring sleeve 10 . The spring fixing hook 12 is fixedly mounted on one end of the spring sleeve 10 .

[0073] In order to prevent the sensor from being corroded by water on the top plate, a sealing waterproof structure is provided at the hole of the wire rope. Specifically, the sealing waterproof structure can be made of sealing grease or a rubber ring.

[0074] A sealing ring installation groove and an optical cable waterproof connector for fixing the optical cable are provided on the rear cover 6. A sealing ring, specifically an O-ring, is installed in the sealing ring installation groove to achieve waterproof sealing of the sensing part.

[0075] The rear tube 5 and the rear cover 6 are connected at their joints by threads, and a sealing ring is provided at the joint, and the sealing ring is an O-ring.

[0076] The components of the delamination instrument sensor, the mounting member 8 and the adjusting member (spring 13, etc.) are all waterproof and sealed. The waterproof and sealing process is a prior art that is well known to those skilled in the art, and the specific sealing process will not be described in detail here.

[0077] The parameters of the sensing part of the combined adjustable range optical fiber multi-point delamination instrument remain unchanged, and only the number of cantilever beams 7 is increased or decreased according to the number of measuring points; the installation adjustment part can achieve the change of the sensor range by adjusting the length, wire diameter and number of turns of the spring sleeve 10 and the spring 13.

[0078] On the other hand, this embodiment also provides a measurement method of the above-mentioned combined range-adjustable optical fiber multi-point delamination instrument, including:

[0079] Install the combined range-adjustable optical fiber multi-point delamination instrument on the structure to be measured;

[0080] After the measured structure is deformed, the anchor claw is pulled, causing the tension piston to extend the traction spring. The extension of the spring is the displacement that the delamination instrument sensor needs to measure.

[0081] The elastic force generated by the extension of the spring is transmitted to the cantilever beam through the wire rope and the guide rod;

[0082] The flexural strain of the cantilever beam is characterized by the wavelength change of the first grating fiber and the second grating fiber;

[0083] Obtain the deformation of the measured structure according to the flexural strain of the cantilever beam;

[0084] The calibration formula of the displacement x, the flexural strain, and the fiber grating wavelength change is:

[0085]

[0086]

[0087] In the above formula:

[0088] ε M is the flexural strain,

[0089] λ B is the central wavelength of the fiber Bragg grating,

[0090] k is the elastic modulus,

[0091] E is the elastic modulus of the cantilever beam,

[0092] h is the thickness of the cantilever beam,

[0093] l is the length of the cantilever beam,

[0094] B is the width of the cantilever beam,

[0095] Δλ B1 is the change in the central wavelength of the first fiber Bragg grating,

[0096] Δλ B2 is the change in the central wavelength of the second fiber Bragg grating.

[0097] like Figure 5 As shown, the combined range-adjustable optical fiber multi-point delamination instrument is installed on the structure to be measured, including:

[0098] S1: drilling a mounting hole 18 on the coal mine roof that is compatible with the mounting parts and adjusting parts of the combined range-adjustable optical fiber multi-point delamination instrument.

[0099] S2: Insert the spring sleeve 10 of the steel wire rope and the adjusting member into the hollow mounting rod, expose the anchor claw 14 at the top of the mounting rod, insert the mounting rod into the mounting hole 18, and push the anchor claw 14 into the old top 19 position of the coal mine roof.

[0100] Specifically, the old roof 19 and the direct roof 20 are terms used in coal mines. The old roof 19 is the basic roof, which is located above the direct roof 20 or the pseudo roof. It is a thick and hard rock layer that is not easy to fall. After the mining is completed, after the direct roof collapses for a period of time, a whole piece of roof rock will collapse, which is the basic roof, commonly known as the "old roof". The first collapse forms the initial pressure of the working face. After that, it collapses every certain distance, forming a periodic pressure. The direct roof 20 is located above the pseudo roof or coal seam (when there is no pseudo roof). It is generally composed of one or several layers of mudstone, shale, siltstone and other rock layers that are relatively easy to collapse, and it collapses after the column is returned.

[0101] In S2, the size of the anchor claw 14 is larger than the inner diameter of the mounting rod. The spring tube and the first steel wire rope 91 where the first anchor claw 141 is located are inserted into the hollow mounting rod. The first anchor claw 141 is exposed at the top of the mounting rod. The mounting rod is inserted into the mounting hole 18, and the first anchor claw 141 is pushed into the top plate at the old top 19 position with force. The depth of this position can be determined according to the insertion length of the mounting rod.

[0102] S3: Pull out the installation rod, and gently pull the first steel wire rope 91 to ensure that the first anchor claw 141 is stuck in the installation hole 18.

[0103] S4: Repeat S2 and S3 to place N sets of adjustment components and steel wire rope assemblies into the mounting hole, where N is a natural number greater than 1. Specifically, the second anchor claw 142-spring sleeve 10-second steel wire rope 92 assembly, the third anchor claw 143-spring sleeve 10-third steel wire rope 93 assembly, and the anchor claw N-spring sleeve N-steel wire rope N assembly are sequentially placed into the predetermined position of the mounting hole 18.

[0104] S5: insert the plurality of steel wire ropes 9 in the previous steps into the sleeve 15 of the mounting member 8, and insert the mounting member 8 into the mounting hole 18 to fix it.

[0105] S6: Unscrew the rear tube 5 of the sensor, and pass the steel wire rope 9 through the steel wire rope through hole on the base plate 1 and the threaded hole on the guide rod 4 in sequence.

[0106] S7: Fasten the base plate 1 and the mounting member 8 with screws.

[0107] S8: Stretch the steel wire ropes and the springs of the adjusting parts in sequence according to the installation order, so that all the steel wire ropes are fixedly connected to the corresponding guide rods. Specifically, stretch the first steel wire rope 91-spring structure so that the first steel wire rope 91 generates prestress, and fix the first steel wire rope 91 to the guide rod 4 through two threaded holes in the guide rod 4; then stretch the second steel wire rope 92-spring structure, the third steel wire rope 93-spring structure, and the steel wire rope N-spring structure in sequence, so that all the steel wire ropes 9 are fixed to the corresponding guide rods 4, and the steel wire ropes 9 are fixed in the threaded holes of the guide rod 4 by screws.

[0108] S9: Cut off the excess part of the wire rope, tighten the rear cylinder 5, and install the protective shell of the delamination instrument sensor 16, completing the installation of the combined range-adjustable optical fiber multi-point delamination instrument.

[0109] The rear cover 6 is provided with an optical cable waterproof connector for connecting the tail cable 17 .

[0110] To ensure the accuracy of the sensor measurement data, the sensor can be calibrated after packaging. The calibration equipment is an electronic displacement calibration platform. The electronic displacement calibration platform is a product in the existing technology, such as the HLC series precision linear displacement sensor.

[0111] The specific calibration process is:

[0112] By fixing the delamination instrument sensor 16 and the steel wire rope 9, setting the calibration interval to 10mm (or other interval length), calibrating from the positive stroke 0mm to the maximum range value, and then calibrating the negative stroke, calibrating from the maximum range to 0mm, and repeating 3 times. During the calibration process, the wavelengths of the first fiber grating and the second fiber grating and the actual displacement of the calibration platform are recorded, and then the values ​​of each parameter are calculated.

[0113] In this embodiment, the flexural strain of the cantilever beam 7 is characterized by the wavelength change of the first grating optical fiber and the second grating optical fiber, and the deformation of the measured structure is obtained according to the flexural strain of the cantilever beam 7. The specific principle and calculation method are as follows:

[0114] Strain ε of a cantilever beam of uniform strength M The relationship with load F is:

[0115]

[0116] Where: E is the elastic modulus of the cantilever beam; h is the thickness of the cantilever beam; l is the length of the cantilever beam; B is the width of the cantilever beam;

[0117] The load F is generated by the extension of the spring according to Hooke's law:

[0118] F=-kx (2)

[0119] Where: k is the elastic coefficient of the spring; x is the deformation of the spring;

[0120] From formula (1) and formula (2), we can know that:

[0121]

[0122] According to existing technology and data, the wavelength change Δλ caused by temperature and strain is known B =0.74λ B ε B , where λ B is the FBG center wavelength (known quantity), ε B is the strain. That is:

[0123]

[0124] After the deformation occurs, the strain of the two gratings is:

[0125] ε B1 =ε T +ε M (5)

[0126] ε B2 =ε T -ε M (6)

[0127] where ε T is the strain caused by temperature, ε M is the strain caused by deflection.

[0128] From equation (5) and equation (6), we can get:

[0129]

[0130] From formula (4), we know

[0131]

[0132] Fiber Bragg Grating (FBG) wavelength variation and flexural strain ε M Linear and one-to-one relationship.

[0133] At the same time, the strain caused by temperature on the grating in the same environment is the same, which is ε T , by combining equation (1), equation (2) and equation (3), ε is eliminated T , thus eliminating the effect of temperature on the desired measurement result ε M impact.

[0134] From formula (3) and formula (8), we can get:

[0135]

[0136]

[0137] When the cantilever beam parameters and spring parameters are fixed, the fiber Bragg grating (FBG) wavelength changes It is linear and one-to-one with the spring extension.

[0138] When the sensor range needs to be changed, just change the spring parameter k.

[0139] When the cross-section of the cantilever beam is circular, the thickness and width of the cantilever beam are its diameter.

[0140] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

[0141] Except for the technical features described in the specification, the remaining technical features are known technologies to those skilled in the art. In order to highlight the innovative features of the present invention, the remaining technical features will not be described here in detail.

Claims

1. A combined range-adjustable optical fiber multi-point delamination instrument, It is characterized in that include: A delamination instrument sensor, the delamination instrument sensor comprises a substrate, at least three cantilever beam fixing positions are arranged on the substrate, the cantilever beam fixing positions are distributed on the same circumference around the center of the substrate, and a plurality of wire rope through holes are arranged at the center of the substrate; a cantilever beam is fixedly installed at the cantilever beam fixing position, a first optical fiber grating is arranged on the upper side of the cantilever beam, and a second optical fiber grating is arranged on the lower side of the cantilever beam; an inner core is also fixedly installed on the substrate, a plurality of through holes are arranged on the inner core, and the through holes are concentric with the end face of the cantilever beam; a guide rod is movably arranged in the through hole, one end of the guide rod passes through the through hole and presses against the force point of the cantilever beam, and one or more threaded holes are arranged at the other end of the guide rod; a wire rope is fixed in the threaded hole, and the wire rope passes through the cantilever beam and the substrate and extends to the other side of the substrate; A mounting member, one end of which is mounted on the base plate, and the other end of which is provided with a sleeve, an outer wall of which is provided with a claw hook, and the steel wire rope passes through the sleeve and extends out from the end of the sleeve; An adjusting member, wherein the adjusting member comprises a spring, one end of the spring is connected to a spring fixing hook, and the other end of the spring is connected to a stretching piston; the other side of the stretching piston is connected to the steel wire rope, and the other side of the spring fixing hook is connected to an anchor claw; A protective shell is arranged on the substrate of the delamination instrument sensor, and the protective shell includes a cylinder and a rear cylinder. One end of the cylinder is connected to the substrate, and the other end of the cylinder is provided with a rear cover. The rear cylinder is mounted on the rear cover and communicated with the cylinder, and the diameter of the rear cylinder is smaller than that of the cylinder. The protective shell covers the cantilever beam, the inner core and the guide rod. The spring and the stretching piston are both located in the spring sleeve, the stretching piston can move along the spring sleeve, and the spring fixing hook is fixedly installed at one end of the spring sleeve.

2. The combined range-adjustable optical fiber multi-point delamination instrument according to claim 1, It is characterized in that A sealing and waterproof structure is arranged at the penetration hole of the steel wire rope.

3. The combined range-adjustable optical fiber multi-point delamination instrument according to claim 1, It is characterized in that The rear cover is provided with a sealing ring installation groove and an optical cable waterproof connector for fixing the optical cable.

4. The combined range-adjustable optical fiber multi-point delamination instrument according to claim 1 or 3, It is characterized in that The matching part of the rear tube and the rear cover is connected by threads, and a sealing ring is arranged at the connection part.

5. The combined range-adjustable optical fiber multi-point delamination instrument according to claim 1, It is characterized in that The components of the delamination instrument sensor, the mounting part and the adjusting part are all treated with waterproof sealing.

6. A measurement method for a combined range-adjustable optical fiber multi-point delamination instrument as claimed in any one of claims 1 to 3, It is characterized in that include: Install the combined range-adjustable optical fiber multi-point delamination instrument on the structure to be measured; After the measured structure is deformed, the anchor claw is pulled, causing the tension piston to extend the traction spring. The extension of the spring is the displacement that the delamination instrument sensor needs to measure. The elastic force generated by the extension of the spring is transmitted to the cantilever beam through the wire rope and the guide rod; The flexural strain of the cantilever beam is characterized by the wavelength change of the first grating fiber and the second grating fiber; Obtain the deformation of the measured structure according to the flexural strain of the cantilever beam; The calibration formula of the displacement x, the flexural strain, and the fiber grating wavelength change is: In the above formula: ε M is the flexural strain, λ B is the central wavelength of the fiber Bragg grating, k is the elastic modulus, E is the elastic modulus of the cantilever beam, h is the thickness of the cantilever beam, l is the length of the cantilever beam, B is the width of the cantilever beam, Δλ B1 is the change in the central wavelength of the first fiber Bragg grating, Δλ B2 is the change in the central wavelength of the second fiber Bragg grating.

7. The measuring method according to claim 6, It is characterized in that The combined range-adjustable optical fiber multi-point delamination instrument is installed on the structure to be measured, comprising: S1: drilling mounting holes on the roof of the coal mine that are compatible with mounting parts and adjusting parts of the combined range-adjustable optical fiber multi-point separation instrument; S2: Insert the wire rope and the spring sleeve of the adjusting piece into the hollow mounting rod, expose the anchor claw at the top of the mounting rod, insert the mounting rod into the mounting hole, and push the anchor claw into the old top position of the coal mine roof; S3: Pull out the mounting rod and gently pull the wire rope to ensure that the anchor claw is stuck in the mounting hole; S4: Repeat S2 and S3 to place N sets of adjustment parts and steel wire rope assemblies into the installation holes, where N is a natural number greater than 1; S5: inserting a plurality of steel wire ropes into the sleeve of the mounting member, and inserting the mounting member into the mounting hole to fix it; S6: Pass the steel wire rope through the steel wire rope through-hole on the base plate and the threaded hole on the guide rod in sequence; S7: Fixing the base plate and the mounting member together; S8: Stretch the steel wire ropes and the springs of the adjusting parts in sequence according to the installation order, so that all the steel wire ropes are fixedly connected to the corresponding guide rods; S9: Cut off the excess part of the wire rope, install the protective shell of the delamination meter sensor, and complete the installation of the combined range-adjustable optical fiber multi-point delamination meter.

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