Optical fiber integrated sensor for rock mass fracture positioning

Abstract

The invention discloses an optical fiber integrated sensor for rock mass fracture positioning, relates to the field of monitoring equipment, and has a good monitoring effect on fracture signals. The optical fiber integrated sensor comprises a deformable body and an optical fiber, the deformable body deforms when sensing the fracture signal, so that the first optical fiber coil and the second optical fiber coil on the peripheral wall of the deformable body deform; the first optical fiber coil spirally wound on the deformable body can monitor longitudinal and transverse strain perpendicular to the axial direction of the deformable body caused by vibration, and the second optical fiber coil is provided with two or more linear segments which are uniformly distributed around the circumferential direction of the deformable body and are arranged along the axial direction of the deformable body; and the strain in the axial direction of the deformable body caused by vibration can be monitored. Therefore, the optical fiber integrated sensor can simultaneously monitor the components of the fracture signal in three mutually perpendicular directions, and has a good monitoring effect on the fracture signal generated by the rock body.

Description

Technical Field

[0001] The invention belongs to the field of monitoring equipment, and in particular relates to an optical fiber integrated sensor for locating rock body fractures. Background Art

[0002] With the further development of science and technology, my country's engineering projects have entered the deep earth field. Deep underground projects such as deep underground tunnels, underground powerhouses of water conservancy and hydropower facilities, deep underground nuclear waste disposal laboratories, and deep physical underground laboratories are being built rapidly. However, the deeper the engineering project is buried, the more complex the geological environment of the engineering rock body is. The biggest challenge is the initial high ground stress field of the surrounding rock. Excavation in this high ground stress field rock body environment will destroy the initial equilibrium stress field of the rock body, and the strain energy stored in the rock body will be suddenly and violently released. When this part of energy exceeds the strength of the rock body itself, a large amount of rock body will burst, collapse or eject, causing serious damage to the excavation working face, equipment damage or casualties. For example, during the construction of Jinping II Hydropower Station in my country, rock bursts occurred more than 750 times, the water diversion tunnel of Minjiang Taipingyi Hydropower Station occurred more than 400 times, and the Erlangshan Tunnel occurred more than 200 times, causing many casualties and countless property losses. Therefore, how to monitor and prevent rock bursts and effectively curb the occurrence of high-intensity rock burst disasters has become a major problem to be solved in the safe construction of projects such as water conservancy and hydropower, transportation, national defense, deep physics laboratories, and the safe and efficient mining of metal mines in my country.

[0003] Rockburst is caused by the sudden and violent release of elastic deformation potential accumulated in the rock body due to external disturbance. Before the rock body breaks, only the internal deterioration of the rock body occurs, there will be slight vibrations, and sounds that cannot be distinguished by human ears. Rock body ruptures usually occur within 24 hours after the rock body is excavated, and the duration is generally 1 to 2 months, and some extend for more than 1 year. In severe cases, earthquakes of magnitude 4 to 6 can be detected, with an intensity of 7 to 8 degrees. Therefore, how to monitor and predict rock body rupture based on the characteristics of vibration and sound generated before and during rock body rupture, determine the location, magnitude, and possible duration of rock body rupture, and take corresponding preventive measures, can greatly reduce or eliminate the casualties and property losses of construction personnel caused by rock body rupture.

[0004] At present, the on-site measurement prediction of rockburst is mainly carried out during the construction period to predict the location and possibility of rockburst through on-site monitoring methods, such as microseismic (MS) method, acoustic emission (AE) method, drill cuttings method, electromagnetic radiation (EMR) method, distributed optical fiber monitoring method, etc., but the above methods all have shortcomings. For example, the use of microseismic method to monitor rockburst requires the deployment of multiple microseismic sensors, which is expensive, and requires drilling in areas with rockburst risks, which poses a potential threat to the life safety of workers. When it is applied to deep underground rock body engineering, it is difficult to realize the real-time transmission of monitoring data, and the accuracy of earthquake source positioning depends on the determination of formation wave velocity, and the positioning accuracy is often not ideal. The acoustic emission method has problems such as weak effective signal, strong noise interference, and inaccurate monitoring results. The drill cuttings method has problems such as cumbersome operation and inability to monitor in real time. The monitoring of electromagnetic radiation method is easily interfered by the surrounding environment. For example, factors such as electrical equipment and weather changes may affect the monitoring results. Especially in the complex geological environment of deep ground, the propagation and reception of signals are easily hindered, and the use and maintenance costs are relatively high. The distributed optical fiber monitoring method uses optical fibers attached to the cave wall to monitor the vibration and sound and other rupture signals generated before and during the rock body damage. There are problems such as relatively scattered monitoring signals, difficult deployment, and low survival rate in complex geological environments. For example: The Chinese utility model patent with the authorization announcement number CN212003266U discloses a rock burst monitoring system based on distributed optical fiber sensing, which uses multiple monitoring armored optical cables to be installed and fixed along the top and supporting rock or supporting walls on both sides of the tunnel being excavated or completed, or on the working surface being excavated along the mountain or ore body; one end of the multiple monitoring armored optical cables is connected to a multi-channel broadband distributed optical fiber acoustic wave and strain sensing modulation and demodulation system, and the multi-channel broadband distributed optical fiber acoustic wave and strain sensing modulation and demodulation system is connected to a real-time data recording and processing computer. Since deep underground tunnel chambers are generally excavated by blasting, the surrounding rock of the tunnel wall has large fluctuations. Using optical fiber strips for rockburst monitoring will result in poor coupling between the optical fiber and the surrounding rock. Moreover, only the component of the rupture signal along the axial direction of the tunnel can be monitored, which is not ideal for monitoring the rupture signal. In addition, in order to couple the optical fiber with the surrounding rock, it is often necessary to bend the optical fiber to a large extent at the monitoring point, thereby greatly reducing the survival rate of the optical fiber.

[0005] Therefore, there is an urgent need in the art for an optical fiber integrated sensor for locating rock fractures to solve the above technical problems. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an optical fiber integrated sensor for locating rock body fractures, which has a good monitoring effect on rock body fracture signals.

[0007] The technical solution adopted by the present invention to solve the technical problem is: an optical fiber integrated sensor for locating rock body fractures comprises a deformable body and an optical fiber, wherein the optical fiber comprises a first optical fiber segment and a second optical fiber segment connected to each other;

[0008] The first optical fiber segment is arranged on the peripheral wall of the deformation body and is spirally wound around the axial direction of the deformation body for at least one circle to form a first optical fiber coil;

[0009] The second optical fiber segment includes a straight line segment arranged on the peripheral wall of the deformation body along the axial direction. The straight line segments are at least two and are evenly distributed around the circumference of the deformation body. The straight line segments are connected end to end in sequence through an arc-shaped reversing segment to form a second optical fiber coil with a continuous optical path.

[0010] Furthermore, the deformation body is cylindrical.

[0011] Furthermore, the optical fiber integrated sensor also includes a vibration conduction component;

[0012] The vibration transmission component is arranged at the bottom of the deformation body, and is used for transmitting the vibration generated by the fracture of the rock body to the deformation body.

[0013] Further, the vibration conduction component includes a rigid conduction sheet and a rigid vibration ball;

[0014] One side surface of the rigid conductive sheet is attached to the bottom surface of the deformable body;

[0015] The rigid vibration balls are arranged on the other side surface of the rigid conductive sheet. There are at least three rigid vibration balls and they are distributed in a circular array with the extension line of the axis of the deformable body as the array center line.

[0016] Furthermore, the optical fiber integrated sensor further comprises a protective housing, wherein the protective housing cover is arranged outside the deformation body;

[0017] The vibration conducting component is at least partially exposed outside the protective shell.

[0018] Furthermore, the optical fiber integrated sensor further comprises an optical fiber guide tube, wherein the optical fiber guide tube comprises an inner guide tube and an outer guide tube;

[0019] The inner guide tube is inserted into the protective shell along the axial direction of the deformation body;

[0020] The outer guide tube is arranged outside the protective shell, and a partial tube section thereof is opened and connected to a tube opening at one end of the inner guide tube;

[0021] The optical fiber also includes an incoming optical fiber segment and an outgoing optical fiber segment;

[0022] The tail end of the optical fiber segment enters the optical fiber guide tube from one end of the outer guide tube, passes through the side of the inner guide tube, and is connected to the head end of the first optical fiber segment;

[0023] The head end of the lead-out optical fiber segment is connected to the tail end of the second optical fiber segment, and the tail end thereof passes through the optical fiber guide tube from the side of the inner guide tube and passes through the other end of the outer guide tube.

[0024] Furthermore, the inner guide tube and the outer guide tube are perpendicular to each other, and the middle portion of the outer guide tube is open and connected to one end of the inner guide tube to form a "T"-shaped optical fiber guide tube.

[0025] Furthermore, the optical fiber integrated sensor also includes a rock body coupling component;

[0026] The rock body coupling component is arranged at the bottom of the vibration conduction component and is used for coupling connection with the rock body.

[0027] Furthermore, the rock body coupling component is a coupling cone head, and the coupling cone head is connected to the bottom of the vibration conduction component through its bottom surface.

[0028] Furthermore, the coupling cone head and the deformation body remain coaxial.

[0029] The beneficial effects of the present invention are as follows:

[0030] (1) The optical fiber integrated sensor can be installed at the surrounding rock monitoring point of a tunnel or cavern to effectively monitor the fracture signals such as vibration and sound generated before and during the rock body failure. When the deformable body senses the fracture signal, it will deform, thereby causing the first optical fiber coil and the second optical fiber coil on the peripheral wall of the deformable body to deform, thereby realizing the monitoring of the fracture signal. Since the optical fiber can monitor the fracture signal along its axial direction, the first optical fiber coil that is spirally wound around the axial direction of the deformable body for at least one circle can effectively monitor the longitudinal and transverse strains perpendicular to the axial direction of the deformable body caused by vibration, and the second optical fiber coil that has two or more straight segments uniformly distributed around the circumference of the deformable body and arranged along the axial direction of the deformable body can monitor the strain along the axial direction of the deformable body caused by vibration. It can be seen that the optical fiber integrated sensor can simultaneously obtain the components of the fracture signal in the three directions of X, Y, and Z, and has a good monitoring effect on the fracture signals such as vibration and sound generated before and during the rock body failure.

[0031] (2) The vibration transmission component can transmit the rupture signal to the deformable body in a concentrated manner, which is beneficial to improving the sensitivity and accuracy of monitoring.

[0032] (3) The fiber optic integrated sensor is coupled to the rock body through the rock body coupling component to improve the monitoring effect. When the rock body coupling component is a coupling cone head, it is particularly suitable for use in tunnels or caverns with large wall undulations to ensure that the fiber optic integrated sensor can be fully coupled to the rock body to achieve the best monitoring effect.

[0033] The technical effects brought about or directly produced by other technical features of the present invention will be described in detail in the subsequent specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the implementation structure of an implementation mode of the present invention;

[0035] Figure 2 It is an analysis diagram of the monitoring rupture signal when the optical fiber is wound;

[0036] Figure 3 yes Figure 2 A schematic diagram of an unfolded state of an optical fiber in a winding arrangement;

[0037] Figure 4 is based on Figure 2 The relationship diagram between the local coordinate system n-axis and the global coordinate system;

[0038] Figure 5 It is a schematic diagram of the implementation structure of another embodiment of the present invention;

[0039] Marked in the figure are: deformable body 100, entering optical fiber segment 210, first optical fiber coil 220, second optical fiber coil 230, straight segment 231, arc-shaped reversing segment 232, lead-out optical fiber segment 240, vibration conduction component 300, rigid conduction sheet 310, rigid vibration ball 320, protective shell 400, optical fiber guide tube 500, inner guide tube 510, outer guide tube 520, coupling cone head 600. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. The same reference numerals in the accompanying drawings represent components with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate directions or positions, and dimensional relationships based on the directions or position relationships shown in the accompanying drawings, and are only for the convenience of description, and do not indicate or imply that the referred device or component must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0042] When the terms "about", "around", etc. are used to describe a numerical range, they usually refer to an error within ±10%. For example, "around 100 mm" refers to 90 to 110 mm. When the term "plurality" is used to indicate a quantity, it usually refers to a quantity of three or more. For example, "multiple" usually refers to three or more. The expression "mainly composed of..." is interpreted as also containing structural components not mentioned in the sentence. The term "and / or" is merely a description of an associative relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0043] like Figure 1 As shown, the optical fiber integrated sensor for locating rock body fractures comprises a deformable body 100 and an optical fiber, wherein the optical fiber comprises a first optical fiber segment and a second optical fiber segment that are connected to each other;

[0044] The deformable body 100 is a component that will produce elastic deformation under the action of load (such as vibration); the deformable body 100 is usually made of elastic material, preferably made of rubber; the deformable body 100 is usually a regular columnar structure, preferably a cylindrical structure, so as to ensure that it can produce deformation adapted to the vibration size, vibration frequency and vibration direction under the action of vibration, so as to ensure the monitoring effect;

[0045] Optical fiber is the abbreviation of optical fiber, which is a fiber made of glass or plastic; optical fiber can be bare optical fiber or armored optical fiber;

[0046] The first optical fiber segment is arranged on the peripheral wall of the deformable body 100, and is spirally wound around the axial direction of the deformable body 100 for at least one circle to form a first optical fiber coil 220; because the optical fiber can monitor the rupture signal along its axial direction, and each circle of the first optical fiber coil 220 is nearly perpendicular to the axial direction of the deformable body 100, the first optical fiber coil 220 can effectively monitor the longitudinal and transverse strains perpendicular to the axial direction of the deformable body 100 caused by vibration; the more circles of the first optical fiber coil 220 and the smaller the distance between two adjacent circles, the better the monitoring effect; the specific number of circles of the first optical fiber coil 220 and the distance between two adjacent circles can usually be determined based on comprehensive consideration of factors such as actual monitoring effect requirements, production cost, production difficulty, and signal collection amount;

[0047] The second optical fiber segment includes a straight segment 231 arranged on the peripheral wall of the deformable body 100 along the axial direction thereof, and there are at least two straight segments 231 that are evenly distributed around the circumference of the deformable body 100. The straight segments 231 are connected end to end in sequence through the arc-shaped reversing segment 232 to form a second optical fiber coil 230 with a continuous optical path; the arc-shaped reversing segment 232 is usually smoothly connected with the straight segment 231, and the curvature of the arc-shaped reversing segment 232 must be sufficient to basically not affect the signal transmission of the optical fiber; the strain along the axial direction of the deformable body 100 caused by vibration can be effectively monitored through the straight segment 231. The more straight segments 231 there are, the higher the monitoring accuracy is, but it will cause signal acquisition redundancy. Therefore, the specific number of straight segments 231 can usually be determined based on comprehensive consideration of factors such as monitoring effect requirements, the minimum curvature of the arc-shaped reversing segment 232, production cost, production difficulty, and signal acquisition amount.

[0048] It can be seen that the optical fiber integrated sensor can simultaneously obtain the components of the fracture signal in the three directions of X, Y, and Z, and has a good monitoring effect on the fracture signals such as vibration and sound generated before and during the rock mass failure.

[0049] The theoretical basis for the simultaneous monitoring of the components of the rupture signal in three mutually perpendicular directions by optical fiber is as follows:

[0050] Combination Figure 2 , Figure 3 and Figure 4 Analyze the crack signal components that can be monitored when the optical fiber is wound. Figure 2 Point P is any position on the optical fiber, α is the winding angle, corresponding to Figure 1 In the embodiment, the tilt angle of the front view projection of the first optical fiber coil 220 corresponds to Figure 2 The angle between the axial direction of the optical fiber and the tangent line of the deformed body at point A; AA′ is the optical fiber winding section, e x 、e y 、e zare the strains of the X, Y, and Z components caused by vibration at the location of the optical fiber. They are actual quantities and are calculated according to formulas 1 to 5. Because only the axial strain of the optical fiber can be obtained during the monitoring process, e x 、e y 、e z The three component strains can be obtained by calculating the winding angle α and the following other parameters. is the axial strain of the optical fiber at point P, P-lmn is the local coordinate system of point P, n direction is the axial direction of the optical fiber winding section, θ is the rotation angle, θ nx is the angle between the n-axis in the local coordinate system P-lmn coordinate system and the x-axis in the global coordinate system. Similarly: θ ny is the angle between the n-axis in the local coordinate system P-lmn coordinate system and the y-axis in the global coordinate system, θ nz It is the angle between the n-axis in the local coordinate system P-lmn coordinate system and the z-axis in the global coordinate system.

[0051] Depend on Figure 2 , Figure 3 and Figure 4 It can be deduced that the axial strain of the optical fiber at point P is The relationship with the three strain components is:

[0052]

[0053] Three coefficients R that affect the axial strain of optical fiber nx , R ny , R nz They are:

[0054]

[0055] θ nx ,θ ny ,θ nz The relationship with the winding angle α is:

[0056]

[0057] Where: R nx , R ny , R nz They represent the direction cosines between the n-axis and the x-, y-, and z-axes respectively; r is the fiber winding radius. Figure 1 or Figure 5 In the embodiment, r is equal to the radius of the deformable body 100. k is Figure 2 h is the length of the AP segment in the unfolded state of the optical fiber in the winding setting; h is the height of point P in the unfolded state of the optical fiber in the winding setting.

[0058] Formula 2 can be expressed in matrix as:

[0059]

[0060] It can be shortened to:

[0061] E=GE 0 ……(Formula 5);

[0062] Where: E is the axial strain matrix of the fiber in the winding arrangement; G is R nx , R ny , R nz The expansion matrix composed of E 0 The actual three-component strain e of the optical fiber set up for winding x 、e y 、e z The matrix formed.

[0063] Based on formulas 1 to 5, the strain E of the optical fiber monitoring point in the three-component region can be calculated according to the collected optical fiber axial strain E. 0 From formulas 1 to 5, we can see that the three strain components generated by the fiber receiving the rupture signal are related to the winding angle α. When α increases, e z The weight increases, and e x and e y The component strain decreases, and when α decreases, e z The weight decreases, and e x and e y The component increases. Therefore, in order to be able to monitor the three more obvious strain component signals at the same time. Therefore, the present invention adopts two different winding methods to set the optical fiber segment on the deformable body 100, that is, one is a first optical fiber segment, which is arranged on the peripheral wall of the deformable body 100 and is spirally wound around the axial direction of the deformable body 100 for at least one circle to form a first optical fiber coil 220; the other is a second optical fiber segment, which includes a straight line segment 231 arranged on the peripheral wall of the deformable body 100 along the axial direction, and the straight line segments 231 are at least two and are evenly distributed around the circumference of the deformable body 100. The straight line segments 231 are connected end to end in sequence through the arc-shaped reversing segment 232 to form a second optical fiber coil 230 with a continuous optical path; the winding angle α of the straight line segment 231 is 90°, and the e monitored by it is z When the winding angle α of the first optical fiber coil 220 is close to 0°, the monitored e x and e y The component is close to the maximum value.

[0064] like Figure 1 or Figure 5As shown, in some embodiments of the present invention, the first optical fiber coil 220 is located at the lower side of the second optical fiber coil 230, and the first optical fiber coil 220 is wound from bottom to top. Such a configuration is not only compact in structure, but also conducive to ensuring the continuity of the optical path of the optical fiber, so as to ensure the sensitivity and accuracy of monitoring. The winding angle α of the first optical fiber coil 220 should be as small as possible, and the winding length can be determined according to factors such as actual measurement requirements and the size of the deformable body 100, and is usually wound about 1m.

[0065] In some embodiments of the present invention, the optical fiber integrated sensor further includes a vibration transmission component 300; the vibration transmission component 300 is disposed at the bottom of the deformable body 100, and is used to transmit the vibration generated by the rock body fracture to the deformable body 100, so as to improve the monitoring sensitivity and accuracy. The vibration transmission component 300 can be of various types, usually a component made of a rigid material, preferably a component made of solid metal.

[0066] For example Figure 1 or Figure 5 As shown, in some embodiments of the present invention, the vibration conduction component 300 includes a rigid conduction sheet 310 and a rigid vibration ball 320;

[0067] One side surface of the rigid conductive sheet 310 is attached to the bottom surface of the deformable body 100, and is used to uniformly conduct the vibration energy to the deformable body 100; the rigid conductive sheet 310 is usually a sheet-shaped component adapted to the bottom surface of the deformable body 100, and is usually made of a rigid material, preferably a metal material, such as a steel sheet made of steel; the rigid conductive sheet 310 can also prevent the rigid vibration ball 320 from directly contacting the deformable body 100, thereby preventing the vibration energy from being consumed or weakened due to the friction effect;

[0068] The rigid vibration balls 320 are arranged on the other side surface of the rigid conductive sheet 310. There are at least three rigid vibration balls 320 and they are distributed in a circular array with the extension line of the axis of the deformable body 100 as the center line of the array. Since the rigid vibration balls 320 have a regular shape and high dimensional accuracy, they can accurately transmit vibrations. Moreover, the rigid vibration balls 320 have high hardness and rigidity, which can reduce energy loss in the process of transmitting vibrations. In addition, the rigid vibration balls 320 distributed in a plurality of circular arrays can ensure that they can evenly transmit rupture signals. Therefore, when the rigid vibration balls 320 are affected by external vibrations, only a small elastic deformation will occur, and they will quickly recover and generate vibration waves. These vibration waves will propagate along the rigid vibration balls 320, thereby accurately and efficiently transmitting the rupture signals to the rigid conductive sheet 310. The rigid vibration balls 320 are made of rigid material, preferably made of metal material, such as steel balls made of steel.

[0069] In order to simplify the structure and ensure a good vibration conduction effect, in some embodiments of the present invention, the number of the rigid vibration balls 320 is preferably set to three or four.

[0070] In order to effectively reduce the loss of vibration energy at the connection between the rigid vibration ball 320 and the rigid conductive sheet 310 and improve the connection effect, in some embodiments of the present invention, it is preferred to make the rigid vibration ball 320 and the rigid conductive sheet 310 face-to-face contact, that is, an arc-shaped groove is provided on the other side surface of the rigid conductive sheet 310, so that a part of the rigid vibration ball 320 is embedded in the arc-shaped groove to form an arc-shaped surface-fit connection.

[0071] For example Figure 1 or Figure 5 As shown, in some embodiments of the present invention, the optical fiber integrated sensor further comprises a protective housing 400, which is disposed outside the deformable body 100; the vibration transmission component 300 is at least partially exposed outside the protective housing 400. The protective housing 400 is mainly used to protect the sensor components installed inside it and reduce the external interference to the optical fiber integrated sensor; the protective housing 400 is usually made of metal material, which can be of various structures, preferably a cylindrical or inverted frustum-shaped housing.

[0072] In some embodiments of the present invention, the bottom of the protective shell 400 is open, the deformable body 100 is disposed in the protective shell 400 and fixed in a compressed state between the inner top surface of the protective shell 400 and the vibration conduction component 300, and the exposed portion of the vibration conduction component 300 is exposed from the opening at the bottom of the protective shell 400.

[0073] For the vibration conduction component 300 mainly composed of a rigid conduction sheet 310 and a rigid vibration ball 320, when the rupture signal is transmitted to the rigid vibration ball 320, it will cause multiple uniformly distributed rigid vibration balls 320 to vibrate, and then the rigid vibration ball 320 will evenly distribute the rupture signal to the deformable body 100 through the rigid conduction sheet 310, thereby causing the deformable body 100 to produce a uniform deformation corresponding to the rupture signal, and the deformation of the deformable body 100 will cause the first optical fiber coil 220 and the second optical fiber coil 230 to deform, causing the optical signal inside the optical fiber to change, and finally the rupture signal will be restored, thereby realizing the monitoring of the rupture signal.

[0074] For example Figure 1 or Figure 5As shown, in some embodiments of the present invention, the optical fiber integrated sensor further includes an optical fiber guide tube 500, and the optical fiber guide tube 500 includes an inner guide tube 510 and an outer guide tube 520; the inner guide tube 510 is inserted into the protective housing 400 along the axial direction of the deformable body 100; the outer guide tube 520 is arranged outside the protective housing 400, and a partial pipe section thereof is opened and connected to one end of the inner guide tube 510;

[0075] The optical fiber also includes an entry optical fiber segment 210 and an exit optical fiber segment 240; the tail end of the entry optical fiber segment 210 passes through the optical fiber guide tube 500 from one end of the outer guide tube 520, passes through the side of the inner guide tube 510, and is connected to the head end of the first optical fiber segment; the head end of the exit optical fiber segment 240 is connected to the tail end of the second optical fiber segment, and its tail end passes through the optical fiber guide tube 500 from the side of the inner guide tube 510, and passes through the other end of the outer guide tube 520.

[0076] The fiber segment 210 entering and the fiber segment 240 exiting are usually protected by armor; the armor is usually made of corrosion-resistant and anti-aging materials, preferably made of rubber. The fiber guide tube 500, which is mainly composed of an inner guide tube 510 and an outer guide tube 520, is used for guiding the fiber to enter and exit, and conveniently optically connecting with other optical fibers and / or other fiber integrated sensors, and protecting this part of the fiber segment from external factors; the inner guide tube 510 is inserted into the protective shell 400 along the axial direction of the deformable body 100, so that the entire fiber integrated sensor structure is compact and convenient for the installation of the deformable body 100. The tail end of the fiber segment 210 entering is passed out from the side of the inner guide tube 510, so as to be directly connected to the first fiber segment wound on the deformable body 100; the tail end of the fiber segment 240 exiting is passed into the fiber guide tube 500 from the side of the inner guide tube 510, so as to be directly connected to the second fiber segment wound on the deformable body 100; in this way, the fiber segments used for connection can be reduced, which is conducive to improving the accuracy of monitoring. The exposed connection ends of the incoming optical fiber segment 210 and the outgoing optical fiber segment 240 are respectively passed through the two end pipe openings of the outer guide tube 520, so that the optical fiber integrated sensor can be connected with other optical components during use and is convenient for maintenance.

[0077] In order to further facilitate the use and maintenance of the optical fiber integrated sensor, Figure 1 or Figure 5 As shown, in some embodiments of the present invention, the inner guide tube 510 and the outer guide tube 520 are perpendicular to each other, and the middle portion of the outer guide tube 520 is open and connected to one end of the inner guide tube 510 to form a "T"-shaped optical fiber guide tube 500.

[0078] In order to facilitate the coupling connection between the optical fiber integrated sensor and the rock body to improve the monitoring effect, Figure 5As shown, in some embodiments of the present invention, the optical fiber integrated sensor further includes a rock body coupling component; the rock body coupling component is disposed at the bottom of the vibration transmission component 300, and is used for coupling and connecting with the rock body. The rock body coupling component can be of various types, such as screws, bolts, anchor rods, connection seats, etc.; the specific structure of the rock body coupling component can be selected according to the cave wall surfaces of different flatnesses to ensure that the optical fiber integrated sensor can be fully coupled with the rock body, so as to achieve the best monitoring effect.

[0079] For example Figure 5 As shown, in some embodiments of the present invention, the rock coupling component of the optical fiber integrated sensor is a coupling cone head 600, and the coupling cone head 600 is connected to the bottom of the vibration transmission component 300 through its bottom surface. The coupling cone head 600 has a conical structure, and its tip is convenient for inserting into the rock body, and it can be fully coupled with the rock body to effectively transmit the fracture signal; when the fracture signal is transmitted to the coupling cone head 600, it will cause the vibration transmission component 300 to vibrate. The optical fiber integrated sensor is particularly suitable for use in tunnels or caverns with large wall undulations, such as caverns excavated by blasting.

[0080] In order to further improve the monitoring effect, Figure 5 As shown, in some embodiments of the present invention, the coupling cone head 600 and the deformation body 100 remain coaxial.

[0081] The optical fiber integrated sensor for locating rock fractures provided by the present invention has the advantages of simple installation and layout, recyclability, long-distance monitoring, high sensitivity, low cost, all-weather monitoring, and full-space sound wave / vibration perception. Its spatial distance resolution is as low as less than 1m, and the frequency range of rupture signals that can be identified is 1-2000Hz. It overcomes the problems of relatively scattered monitoring signals of a single bare optical fiber, great difficulty in layout, and low survival rate in complex geological environments. It can be used in complex and deeply buried complex environments, and effectively monitors fracture signals such as vibration and sound generated before and during rock body damage. It can prevent and monitor rock body fractures generated during excavation of deep buried high-stress underground cavern projects, and ensure the safe and smooth construction of deep earth projects.

[0082] The optical fiber integrated sensor for locating rock body fracture provided by the present invention can be deployed according to the on-site engineering conditions, such as being deployed as a sensor array, so as to locate the rock body failure source more conveniently and accurately. When multiple optical fiber integrated sensors are used together, two adjacent optical fiber integrated sensors can be optically connected using armored optical fibers.

[0083] In this article, various embodiments of the present invention may be presented in the form of a range. It should be understood that the description in the form of a range is only for convenience and brevity, and should not be interpreted as a hard limit to the scope of the present invention. Therefore, the description of the range should be considered to specifically disclose all possible sub-ranges and individual numerical values ​​within the range. For example, the description of a range such as from 1 to 6 should be considered to specifically disclose sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and each numerical value within the range, such as 1, 2, 3, 4, 5, 6, which has nothing to do with the width of the range.

[0084] It should be understood that certain features of the invention described in the context of separate embodiments for the sake of clarity may also be provided in combination in a single embodiment. Conversely, various features of the invention described in the context of a single embodiment for the sake of brevity may also be provided individually or in any suitable sub-combination, or in any other described embodiment of the invention where appropriate. Certain features described in the context of various embodiments are not considered essential features of those embodiments unless the embodiments would not function without those features.

[0085] All publications, patents, and patent applications mentioned herein are incorporated herein by reference in their entirety, to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated as being incorporated herein by reference. In addition, the citation or identification of any reference herein should not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, the section headings should not be construed as necessarily limiting.

Claims

1. An optical fiber integrated sensor for locating rock fractures, characterized in that: It comprises a deformable body (100) and an optical fiber, wherein the optical fiber comprises a first optical fiber segment and a second optical fiber segment that are connected to each other; The first optical fiber segment is arranged on the peripheral wall of the deformable body (100) and is spirally wound at least once around the axial direction of the deformable body (100) to form a first optical fiber coil (220); The second optical fiber segment comprises a straight segment (231) arranged on the peripheral wall of the deformable body (100) along the axial direction thereof, the straight segment (231) being at least two and evenly distributed around the circumference of the deformable body (100), and the straight segments (231) being connected end to end in sequence via an arc-shaped reversing segment (232) to form a second optical fiber coil (230) with a continuous optical path.

2. The optical fiber integrated sensor for locating rock fracture according to claim 1, characterized in that: The deformation body (100) is cylindrical.

3. The optical fiber integrated sensor for locating rock fractures according to claim 1, characterized in that: Also included is a vibration conduction component (300); The vibration transmission component (300) is arranged at the bottom of the deformable body (100) and is used to transmit the vibration generated by the fracture of the rock body to the deformable body (100).

4. The optical fiber integrated sensor for locating rock fracture according to claim 3, characterized in that: The vibration conduction component (300) comprises a rigid conduction sheet (310) and a rigid vibration ball (320); One side surface of the rigid conductive sheet (310) is attached to the bottom surface of the deformable body (100); The rigid vibration balls (320) are arranged on the other side surface of the rigid conductive sheet (310). There are at least three rigid vibration balls (320) distributed in a ring array with the extension line of the axis of the deformable body (100) as the array center line.

5. The optical fiber integrated sensor for locating rock fractures according to claim 3, characterized in that: It also includes a protective shell (400), wherein the protective shell (400) is disposed outside the deformable body (100); The vibration conduction component (300) is at least partially exposed outside the protective housing (400).

6. The optical fiber integrated sensor for locating rock fracture according to claim 5, characterized in that: Also included is an optical fiber guide tube (500), wherein the optical fiber guide tube (500) includes an inner guide tube (510) and an outer guide tube (520); The inner guide tube (510) is inserted into the protective outer shell (400) along the axial direction of the deformable body (100); The outer guide tube (520) is arranged outside the protective shell (400), and a partial tube section thereof is opened and connected to a tube opening at one end of the inner guide tube (510); The optical fiber also includes an incoming optical fiber segment (210) and an outgoing optical fiber segment (240); The tail end of the optical fiber segment (210) enters the optical fiber guide tube (500) from one end of the outer guide tube (520), passes out from the side of the inner guide tube (510), and is connected to the head end of the first optical fiber segment; The head end of the lead-out optical fiber segment (240) is connected to the tail end of the second optical fiber segment, and the tail end thereof passes through the optical fiber guide tube (500) from the side of the inner guide tube (510) and passes out from the other end of the outer guide tube (520).

7. The optical fiber integrated sensor for locating rock fracture according to claim 6, characterized in that: The inner guide tube (510) and the outer guide tube (520) are perpendicular to each other, and the middle portion of the outer guide tube (520) is open and connected to one end of the inner guide tube (510), forming a "T"-shaped optical fiber guide tube (500).

8. The optical fiber integrated sensor for locating rock fracture according to any one of claims 3 to 7, characterized in that: Also included are rock mass coupling components; The rock body coupling component is arranged at the bottom of the vibration conduction component (300) and is used for coupling connection with the rock body.

9. The optical fiber integrated sensor for locating rock fractures according to claim 8, characterized in that: The rock body coupling component is a coupling cone head (600), and the coupling cone head (600) is connected to the bottom of the vibration conduction component (300) through its bottom surface.

10. The optical fiber integrated sensor for locating rock fracture according to claim 9, characterized in that: The coupling cone head (600) and the deformation body (100) remain coaxial.

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