Vibration sensor for rock mass fracture monitoring

Abstract

The utility model discloses a vibration sensor for monitoring rock mass fracture, which relates to the field of monitoring equipment, is convenient to couple with rock mass and has a good monitoring effect on fracture signals. The vibration sensor comprises a deformable body, an optical fiber, a vibration conduction assembly and a rock mass coupling part. Through the rock mass coupling component mainly composed of the coupling base and the coupling connecting piece, the vibration sensor is convenient to install and arrange; the deformable body deforms when sensing a fracture signal, so that the first optical fiber coil and the second optical fiber coil 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 with two or more linear segments arranged in the axial direction of the deformable body can monitor strain in the axial direction of the deformable body caused by vibration. Therefore, the vibration sensor has a good monitoring effect on the fracture signal.

Description

Technical Field

[0001] The utility model belongs to the field of monitoring equipment, and in particular relates to a vibration sensor used for monitoring rock mass fracture. 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 mass is. The biggest challenge is the initial high ground stress field of the surrounding rock. Excavation in this high ground stress field rock mass environment will destroy the initial equilibrium stress field of the rock mass, and the strain energy stored in the rock mass will be suddenly and violently released. When this part of energy exceeds the strength of the rock mass itself, a large amount of rock 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 mass due to external disturbance. Before the rock breaks, only the internal deterioration of the rock mass occurs, there will be slight vibrations, and sounds that cannot be distinguished by human ears. Rock breakage usually occurs within 24 hours after the rock mass 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 breakage based on the characteristics of vibration and sound generated before and during rock breakage, determine the location, magnitude, and possible duration of rock breakage, and take corresponding preventive measures, can greatly reduce or eliminate the casualties and property losses of construction personnel caused by rock breakage.

[0004] At present, the on-site measurement and prediction of rock bursts mainly rely on on-site monitoring methods during construction to predict the occurrence location and possibility of rock bursts, such as the microseismic (MS) method, acoustic emission (AE) method, drill cuttings method, electromagnetic radiation (EMR) method, distributed optical fiber monitoring method, etc. However, all of the above methods have deficiencies. Among them, the distributed optical fiber monitoring method uses optical fibers attached to the tunnel wall to monitor rupture signals such as vibrations and sounds generated before and during the occurrence of rock mass failure. There are problems such as relatively scattered monitoring signals, difficult layout, 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. It uses multiple monitoring armored optical cables to be installed and fixed along the top and both sides of the rock mass or support wall of the tunnel being excavated or already completed, or on the working surface being excavated along the mountain body or ore body; one end of each 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 the tunnel chambers buried deep underground are generally excavated by blasting, the surrounding rock of the tunnel wall has large undulations. Using optical fiber strips for rock burst monitoring will result in poor coupling effect between the optical fiber and the surrounding rock; moreover, it can only monitor the component of the rupture signal along the axial direction of the tunnel, and the monitoring effect on the rupture signal is not ideal; 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, thus greatly reducing the survival rate of the optical fiber.

[0005] Therefore, there is an urgent need in the art for a vibration sensor for rock mass rupture monitoring to solve the above technical problems. Summary of the Utility Model

[0006] The present utility model aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present utility model provides a vibration sensor for rock mass rupture monitoring, which is convenient for coupling connection with the rock mass and has a good monitoring effect on the rupture signal of the rock mass.

[0007] The technical solution adopted by the present utility model to solve its technical problems is: A vibration sensor for rock mass rupture monitoring includes a deformable body, an optical fiber, a vibration conduction component, and a rock mass coupling component;

[0008] The optical fiber includes 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 circumferential wall of the deformable body and is wound around the axial direction of the deformable body in a spiral shape for at least one turn to form a first optical fiber coil; the second optical fiber segment includes straight segments arranged on the circumferential wall of the deformable body along the axial direction of the deformable body, and there are at least two straight segments that are evenly distributed around the circumferential direction of the deformable body. Each straight segment is sequentially connected end to end through an arc-shaped commutation segment to form a second optical fiber coil with continuous optical path.

[0009] The vibration conduction component is arranged at the bottom of the deformable body;

[0010] The rock mass coupling component includes a coupling base and a coupling connecting piece; one side surface of the coupling base is attached to the bottom of the vibration conduction component; the coupling connecting piece is arranged on the coupling base, and at least part of its connecting part penetrates out from the other side surface of the coupling base for coupling connection with the rock mass.

[0011] Furthermore, the deformable body is cylindrical.

[0012] Furthermore, the vibration conduction component includes a rigid conduction sheet and rigid vibration balls;

[0013] One side surface of the rigid conduction sheet is attached to the bottom surface of the deformable body;

[0014] The rigid vibration balls are arranged on the other side surface of the rigid conduction sheet, and there are at least three rigid vibration balls, which are annularly arrayed with the extension line of the axis of the deformable body as the array center line.

[0015] Furthermore, the vibration sensor further includes a protective housing, and the protective housing covers the outside of the deformable body;

[0016] At least part of the vibration conduction component is exposed outside the protective housing.

[0017] Furthermore, the protective housing is in the shape of an inverted frustum.

[0018] Furthermore, the vibration sensor further includes an optical fiber guiding tube, and the optical fiber guiding tube includes an inner guiding tube and an outer guiding tube;

[0019] The inner guiding tube is inserted along the axial direction of the deformable body and arranged inside the protective housing;

[0020] The outer guiding tube is arranged outside the protective housing, and a partial pipe section of it is open and connected to one end pipe orifice of the inner guiding tube;

[0021] The optical fiber further includes an entering optical fiber section and an exiting optical fiber section;

[0022] The tail end of the entering optical fiber section penetrates into the optical fiber guiding tube from one end pipe orifice of the outer guiding tube, passes out from the side part of the inner guiding tube, and is connected to the head end of the first optical fiber line segment;

[0023] The head end of the exiting optical fiber section is connected to the tail end of the second optical fiber line segment, and its tail end penetrates into the optical fiber guiding tube from the side part of the inner guiding tube and passes out from the other end pipe orifice of the outer guiding tube.

[0024] Furthermore, there are at least three coupling connecting pieces, which are annularly arrayed with the extension line of the axis of the deformable body as the array center line.

[0025] Further, the coupling connector is a screw or a bolt.

[0026] The beneficial effects of the present utility model are as follows:

[0027] (1) The vibration sensor provided by the present utility model can be conveniently installed at the surrounding rock monitoring points of tunnels or caverns through the rock mass coupling component, and is used to monitor the rupture signals such as vibrations and sounds generated before and during the occurrence of rock mass failure; when the deformable body senses the rupture signal, it will generate deformation, and further cause the first optical fiber coil and the second optical fiber coil on the peripheral wall of the deformable body to deform, realizing the monitoring of the rupture signal; since the optical fiber can monitor the rupture signal along its axial direction, the first optical fiber coil wound around the axial direction of the deformable body in a spiral shape for at least one turn 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 having two or more straight line segments evenly distributed around the circumferential direction 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 this vibration sensor can simultaneously obtain the components in the X, Y, and Z directions corresponding to the rupture signal, and has a good monitoring effect on the rupture signals such as vibrations and sounds generated before and during the occurrence of rock mass failure.

[0028] (2) The rock mass coupling component mainly composed of a coupling base and a coupling connector can not only make the coupling connection effect between the vibration sensor and the rock mass better, but also has a shallow depth of drilling the surrounding rock and a small installation difficulty.

[0029] (3) The rupture signal can be centrally conducted to the deformable body through the vibration conduction component, which is beneficial to improving the sensitivity and accuracy of monitoring.

[0030] The technical effects brought by or directly generated by other technical features of the present utility model will be described in detail in the subsequent specific implementation part. Description of the Drawings

[0031] Figure 1 is the implementation structure schematic diagram of the present utility model;

[0032] Figure 2 is the analysis diagram of monitoring the rupture signal when the optical fiber is wound;

[0033] Figure 3 is Figure 2 the schematic diagram of the unfolded state of the optical fiber wound in

[0034] Figure 4 is based on Figure 2 the relationship diagram of the local coordinate system n-axis and the global coordinate system;

[0035] The labels in the figure are: deformable body 100, incoming optical fiber section 210, first optical fiber coil 220, second optical fiber coil 230, straight section 231, arc-shaped commutation section 232, outgoing optical fiber section 240, vibration conduction assembly 300, rigid conduction sheet 310, rigid vibration ball 320, protective housing 400, optical fiber guiding tube 500, inner guiding tube 510, outer guiding tube 520, coupling base 610, coupling connector 620. Detailed implementation mode

[0036] The following further describes the present utility model in conjunction with the accompanying drawings and embodiments. The same reference numerals in the drawings represent components with the same or similar functions. Although various aspects of the embodiments are shown in the drawings, unless otherwise specified, the drawings do not have to be drawn to scale.

[0037] In the description of the present utility model, it should be understood that terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or position and dimensional relationship based on the orientation or position relationship shown in the drawings, and are only for the convenience of description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present utility model.

[0038] Terms such as "about", "around", etc. usually refer to an error within ±10% when describing a numerical range. For example, about 100 mm usually refers to 90 - 110 mm. When the term "plurality" represents a quantity, it usually refers to a quantity of three or more. For example, "a plurality" usually refers to three or more. The expression of "mainly composed of... or constituted by..." is interpreted as that it can also contain structural components not mentioned in this sentence. The term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the terms "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0039] As Figure 1 shown, the vibration sensor for rock mass fracture monitoring includes a deformable body 100, an optical fiber, a vibration conduction assembly 300, and a rock mass coupling component;

[0040] The deformable body 100 is a component that will produce elastic deformation under the action of a load (such as vibration); the deformable body 100 is usually made of an elastic material, preferably made of rubber; the deformable body 100 is usually a regular columnar structure, preferably cylindrical, to ensure that it can produce a deformation suitable for the vibration magnitude, vibration frequency, and vibration direction under the action of vibration, ensuring the monitoring effect;

[0041] An optical fiber is short for an optical waveguide fiber and is a fiber made of glass or plastic; the optical fiber can be a bare optical fiber or an armored optical fiber; the optical fiber includes a first optical fiber segment and a second optical fiber segment that are connected to each other;

[0042] The first optical fiber segment is arranged on the peripheral wall of the deformable body 100 and is wound around the axis of the deformable body 100 in a spiral shape for at least one turn to form a first optical fiber coil 220; because the optical fiber can monitor the rupture signal along its axis, and each turn of the first optical fiber coil 220 is close to perpendicular to the axis of the deformable body 100, the first optical fiber coil 220 can effectively monitor the longitudinal and transverse strains perpendicular to the axis of the deformable body 100 caused by vibration; the more turns of the first optical fiber coil 220 and the smaller the distance between adjacent turns, the better the monitoring effect; the specific number of turns of the first optical fiber coil 220 and the distance between adjacent turns can usually be determined by comprehensively considering factors such as actual monitoring effect requirements, manufacturing cost, manufacturing difficulty, and signal acquisition volume;

[0043] The second optical fiber segment includes a straight segment 231 arranged on the peripheral wall of the deformable body 100 along the axis of the deformable body 100. There are at least two straight segments 231 and they are evenly distributed around the circumference of the deformable body 100. Each straight segment 231 is connected end to end in sequence through an arc-shaped commutation segment 232 to form a second optical fiber coil 230 with continuous optical path; the arc-shaped commutation segment 232 is usually smoothly connected to the straight segment 231, and the radian of the arc-shaped commutation segment 232 should meet the requirement of basically not affecting the signal transmission of the optical fiber; through the straight segment 231, the strain along the axis of the deformable body 100 caused by vibration can be effectively monitored. The more the number of straight segments 231, the higher the monitoring accuracy, but it will lead to redundant signal acquisition. Therefore, the specific number of straight segments 231 can usually be determined by comprehensively considering factors such as monitoring effect requirements, the minimum radian of the arc-shaped commutation segment 232, manufacturing cost, manufacturing difficulty, and signal acquisition volume;

[0044] The vibration conduction component 300 is arranged at the bottom of the deformable body 100 and is used to conduct the vibration generated by rock rupture to the deformable body 100 to improve the sensitivity and accuracy of monitoring; the vibration conduction component 300 can be of various types and is usually a component made of a rigid material, preferably a component made of metal;

[0045] The rock mass coupling component includes a coupling base 610 and a coupling connecting piece 620; one side surface of the coupling base 610 is attached to the bottom of the vibration conduction component 300; the coupling connecting piece 620 is arranged on the coupling base 610, and at least part of its connecting part penetrates out from the other side surface of the coupling base 610 for coupling connection with the rock mass; the coupling base 610 is used for installing, supporting and vibrating conduction of the vibration sensor, and the coupling connecting piece 620 is used for connecting with the rock mass to make the coupling base 610 fully contact with the rock mass and enhance the conduction of the fracture signal; the coupling connecting piece 620 can be various components such as screws, bolts, anchor rods, etc.

[0046] It can be seen that the vibration sensor provided by the present utility model can simultaneously obtain the components in the X, Y, and Z directions corresponding to the fracture signal, and has a good monitoring effect on the fracture signals such as vibration and sound generated before and during the occurrence of rock mass failure. Moreover, the rock mass coupling component mainly composed of the coupling base 610 and the coupling connecting piece 620 enables the vibration sensor to not only have a good coupling connection effect with the rock mass, but also have a shallow depth of drilling the surrounding rock and a small installation difficulty, and is particularly suitable for tunnels or chambers with relatively flat walls, such as: chambers excavated by TBM (full-face hard rock tunnel boring machine).

[0047] The theoretical basis for the optical fiber to simultaneously monitor the components of the fracture signal in three mutually perpendicular directions is as follows:

[0048] Combined with Figure 2 、 Figure 3 and Figure 4 analyze the fracture signal components that can be monitored when the optical fiber is wound, Figure 2 In, point P is any position on the optical fiber, α is the winding angle, corresponding to Figure 1 the inclination angle of the front view projection of the first optical fiber coil 220 in the implementation manner, or corresponding to Figure 2 the included angle between the axial direction of the optical fiber at point A and the tangent of the circumference of the deformed body; AA' is the optical fiber winding section, e x 、e y 、e z are the strains of the X, Y, and Z components caused by vibration at the position where the optical fiber is located respectively, which are actual quantities and are calculated according to Formulas 1 to 5. Because only the axial strain of the optical fiber can be actually obtained during the monitoring process, so e x 、e y 、e z are calculated jointly according to the winding angle α and the following other parameters to achieve the acquisition of the strains of the three components. is the axial strain of the optical fiber at point P, P-lmn is the local coordinate system of point P, the n direction is the axial direction of the optical fiber winding section, θ is the rotation angle, θ nx is the included angle between the n axis in the local coordinate system P-lmn and the x axis in the global coordinate system. Similarly: θny is the included angle between the n-axis in the local coordinate system P-lmn and the y-axis in the global coordinate system, θ nz is the included angle between the n-axis in the local coordinate system P-lmn and the z-axis in the global coordinate system.

[0049] From Figure 2 , Figure 3 and Figure 4 it can be deduced that the axial strain e of the optical fiber at point P f z has the following relationship with the three strain components:

[0050]

[0051] The three coefficients R nx , R ny , R nz that affect the axial strain of the optical fiber are respectively:

[0052]

[0053] θ nx , θ ny , θ nz has the following relationship with the winding angle α:

[0054]

[0055] In the formula: R nx , R ny , R nz respectively represent the direction cosines between the n-axis and the x, y, and z axes; r is the winding radius of the optical fiber, and in Figure 1 the embodiment, r is equal to the radius of the deformable body 100. k is Figure 2 the length of the AP segment in the unfolded state of the optical fiber wound in

[0056] Formula two can be represented by a matrix as:

[0057]

[0058] It can be abbreviated as:

[0059] E = GE0……(Formula Five);

[0060] In the formula: E is the axial strain matrix of the wound optical fiber; G is the extended matrix composed of R nx , R ny , R nz ; E0 is the actual three-component strain e x , e y , e z of the wound optical fiber.

[0061] Based on Formulas 1 to 5, the strain E0 of the fiber optic monitoring point in three components can be calculated according to the collected axial strain E of the optical fiber. It can be seen from Formulas 1 to 5 that the three strain components generated by the fiber optic receiving the rupture signal are related to the winding angle α. When α increases, the e z component increases, while the e x and e y component strains decrease. When α decreases, the e z component decreases, while the e x and e y components increase. Therefore, in order to be able to simultaneously monitor the three relatively obvious strain component signals. Therefore, the present utility model uses two different winding methods to arrange optical fiber segments on the deformable body 100, that is, one is the first optical fiber line segment, which is arranged on the peripheral wall of the deformable body 100 and spirally winds around the axis of the deformable body 100 for at least one turn to form the first optical fiber coil 220; the other is the second optical fiber line segment, which includes a straight line segment 231 arranged along the axis of the deformable body 100 on its peripheral wall. There are at least two straight line segments 231 and they are evenly distributed around the circumference of the deformable body 100. Each straight line segment 231 is connected end to end in sequence through an arc-shaped commutation segment 232 to form the second optical fiber coil 230 with continuous optical path; the winding angle α of the straight line segment 231 is 90°, and the e z component monitored by it reaches the maximum value; when the winding angle α of the first optical fiber coil 220 approaches 0°, the e x and e y components approach the maximum value.

[0062] Again, as Figure 1 shown, in some embodiments of the present utility model, the first optical fiber coil 220 is located below the second optical fiber coil 230, and the first optical fiber coil 220 winds from bottom to top. With such a setting, not only is the structure compact, but also it is beneficial to ensure the continuity of the optical path of the optical fiber 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 actual measurement requirements and factors such as the size of the deformable body 100. Usually, it winds about 1 m.

[0063] Again, as Figure 1 shown, in some embodiments of the present utility model, the vibration conduction assembly 300 includes a rigid conduction sheet 310 and a rigid vibration ball 320;

[0064] One side surface of the rigid conduction sheet 310 is attached to the bottom surface of the deformable body 100 for uniformly conducting vibration energy to the deformable body 100; the rigid conduction sheet 310 is usually a sheet-like member adapted to the bottom surface of the deformable body 100, usually made of a rigid material, preferably made of a metal material, such as a steel sheet made of steel; the rigid conduction sheet 310 can also prevent the rigid vibration balls 320 from directly contacting the deformable body 100, preventing the consumption or weakening of vibration energy due to the friction effect;

[0065] The rigid vibration balls 320 are arranged on the other side surface of the rigid conduction sheet 310. There are at least three rigid vibration balls 320, which are annularly arrayed with the extension line of the axis of the deformable body 100 as the array center line; because the rigid vibration balls 320 have regular shapes and high dimensional accuracies, they can accurately conduct vibrations; moreover, the rigid vibration balls 320 have high hardness and rigidity, which can reduce energy loss during the transmission of vibrations; in addition, multiple annularly arrayed rigid vibration balls 320 can ensure that they can uniformly conduct fracture signals; therefore, when the rigid vibration balls 320 are affected by external vibrations, only minor elastic deformations will occur, and then they will quickly recover and generate vibration waves, which will propagate along the rigid vibration balls 320, thereby accurately and efficiently conducting the fracture signals to the rigid conduction sheet 310; the rigid vibration balls 320 are usually made of a rigid material, preferably made of a metal material, such as steel balls made of steel.

[0066] In order to simplify the structure and ensure good vibration conduction effects, in some embodiments of the present invention, it is preferred to set the number of the rigid vibration balls 320 to three or four.

[0067] In order to effectively reduce the loss of vibration energy at the connection part between the rigid vibration balls 320 and the rigid conduction sheet 310 and improve the connection effect, in some embodiments of the present invention, it is preferred to make the rigid vibration balls 320 be in surface contact and fit with the rigid conduction sheet 310, that is, an arc-shaped groove is provided on the other side surface of the rigid conduction sheet 310, and a part of the rigid vibration ball 320 is embedded in the arc-shaped groove to form an arc-shaped surface fit connection.

[0068] Another example is Figure 1 As shown, in some embodiments of the present invention, the vibration sensor further includes a protective housing 400, and the protective housing 400 covers the outside of the deformable body 100; at least part of the vibration conduction assembly 300 is exposed outside the protective housing 400. The protective housing 400 is mainly used to protect the sensor components installed inside it and reduce external interference received by the vibration sensor; the protective housing 400 is usually made of a metal material, and it can have various structures, usually a cylindrical or inverted frustum-shaped housing, and the inverted frustum-shaped housing can effectively protect the components inside it and improve the stability of the vibration sensor.

[0069] In some embodiments of the present utility model, the bottom of the protective housing 400 is open. The deformable body 100 is disposed in the protective housing 400 and is fixed in a compressed state between the inner top surface of the protective housing 400 and the vibration conduction assembly 300. The exposed part of the vibration conduction assembly 300 is exposed through the opening at the bottom of the protective housing 400.

[0070] For the vibration conduction assembly 300 mainly composed of a rigid conduction sheet 310 and rigid vibration balls 320, when a rupture signal is conducted to the rigid vibration balls 320, it will cause the uniformly distributed rigid vibration balls 320 to vibrate. Subsequently, the rigid vibration balls 320 distribute the rupture signal evenly to the deformable body 100 through the rigid conduction sheet 310, thereby causing the deformable body 100 to generate a uniform deformation corresponding to the rupture signal. The deformation of the deformable body 100 causes the first optical fiber coil 220 and the second optical fiber coil 230 to deform, causing a change in the optical signal inside the optical fiber, and finally restoring the rupture signal to achieve the monitoring of the rupture signal.

[0071] Again, Figure 1 As shown, in some embodiments of the present utility model, the vibration sensor further includes an optical fiber guiding tube 500. The optical fiber guiding tube 500 includes an inner guiding tube 510 and an outer guiding tube 520. The inner guiding tube 510 is inserted along the axial direction of the deformable body 100 and disposed inside the protective housing 400. The outer guiding tube 520 is disposed outside the protective housing 400, and a partial pipe section thereof is open and connected to one end pipe orifice of the inner guiding tube 510.

[0072] The optical fiber further includes an incoming optical fiber section 210 and an outgoing optical fiber section 240. The tail end of the incoming optical fiber section 210 penetrates into the optical fiber guiding tube 500 from one end pipe orifice of the outer guiding tube 520, passes out from the side of the inner guiding tube 510, and is connected to the head end of the first optical fiber segment. The head end of the outgoing optical fiber section 240 is connected to the tail end of the second optical fiber segment. Its tail end penetrates into the optical fiber guiding tube 500 from the side of the inner guiding tube 510 and passes out from the other end pipe orifice of the outer guiding tube 520.

[0073] Among them, for the incoming optical fiber section 210 and the outgoing optical fiber section 240, they are usually packaged and protected by an armored shell; the armored shell is usually made of corrosion-resistant and anti-aging materials, preferably made of rubber. The optical fiber guiding tube 500 mainly composed of an inner guiding tube 510 and an outer guiding tube 520 is used for guiding the incoming and outgoing of the optical fiber, facilitating optical connection with other optical fibers and / or other vibration sensors, and protecting this part of the optical fiber section from external factors; inserting the inner guiding tube 510 axially along the deformable body 100 into the protective housing 400 can make the entire vibration sensor structure compact and facilitate the installation of the deformable body 100. The tail end of the incoming optical fiber section 210 passes out from the side of the inner guiding tube 510, facilitating direct connection with the first optical fiber line segment wound around the deformable body 100; the tail end of the outgoing optical fiber section 240 passes into the optical fiber guiding tube 500 from the side of the inner guiding tube 510, facilitating direct connection with the second optical fiber section wound around the deformable body 100; in this way, the optical fiber section for connection can be reduced, which is beneficial to improving the monitoring accuracy. The exposed connection ends of the incoming optical fiber section 210 and the outgoing optical fiber section 240 pass out from the two ends of the outer guiding tube 520 respectively, facilitating connection with other optical components during the use of the vibration sensor and facilitating maintenance and servicing.

[0074] To further facilitate the use and maintenance of the vibration sensor, for another example Figure 1 As shown, in some embodiments of the present invention, the inner guiding tube 510 is perpendicular to the outer guiding tube 520, and the middle pipe section of the outer guiding tube 520 is open and connected to one end of the inner guiding tube 510 to form an optical fiber guiding tube 500 with a "T" - shaped structure.

[0075] For another example Figure 1 As shown, in some embodiments of the present invention, there are at least three vibration sensor coupling connectors 620, and they are distributed in a circular array with the extension line of the axis of the deformable body 100 as the array center line. In this way, on the one hand, it is beneficial to effectively fix the vibration sensor and improve its stability, and on the other hand, it is beneficial to the conduction of the rupture signal, improving the monitoring effect of the vibration sensor.

[0076] The vibration sensor for rock mass fracture monitoring provided by the present utility model has the advantages of simple installation and layout, recyclability, long-distance monitoring, high sensitivity, low cost, all-weather monitoring, and full-space acoustic wave / vibration perception. Its spatial distance resolution is as low as less than 1 m, and the frequency range of fracture signals that can be identified is 1 - 2000 Hz. It overcomes the problems of relatively scattered monitoring signals of a single bare optical fiber, difficult layout, and low survival rate in complex geological environments, and can be used in complex deep-buried environments. It can effectively monitor fracture signals such as vibrations and sounds generated before and during the occurrence of rock mass failure, and can prevent and monitor rock fractures generated during the excavation process of deep-buried high-stress underground cavern projects, ensuring the safe and smooth construction of deep-earth projects.

[0077] The vibration sensor for rock mass fracture monitoring provided by the present utility model can be arranged according to the on-site engineering conditions, such as being arranged as a sensor array to more conveniently and accurately locate the source position of rock mass failure. When multiple vibration sensors are used together, optical connection between two adjacent vibration sensors can be achieved using armored optical fibers.

[0078] In this text, various embodiments of the present utility model can be presented in a range form. It should be understood that the description in range form is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present utility model. Therefore, the description of a range should be considered to specifically disclose all possible sub-ranges and individual values within that 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 individual values within that range, such as 1, 2, 3, 4, 5, 6, regardless of the width of the range.

[0079] It should be understood that for the sake of clarity, certain features of the present utility model described in the context of separate embodiments can also be provided in combination in a single embodiment. Conversely, for the sake of brevity, various features of the present utility model described in the context of a single embodiment can also be provided separately, or in any suitable sub-combination, or in any other described embodiment of the present utility model as appropriate. Unless an embodiment does not work without those features, certain features described in the context of various embodiments are not considered essential features of those embodiments.

[0080] All publications, patents, and patent applications mentioned in this text are hereby incorporated by reference in their entirety as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. In addition, the citation or identification of any reference in this text should not be construed as an admission that such reference can be used as prior art for the present utility model. Regarding the use of section headings, the section headings should not be construed as essential limitations.

Claims

1. A vibration sensor for monitoring rock fracture, characterized in that: It comprises a deformable body (100), an optical fiber, a vibration conduction component (300) and a rock mass coupling component; The optical fiber comprises a first optical fiber segment and a second optical fiber segment which 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 line segment (231) arranged on the peripheral wall of the deformable body (100) along the axial direction thereof, the straight line segments (231) being at least two and evenly distributed around the circumference of the deformable body (100), the straight line segments (231) being connected end to end in sequence through an arc-shaped reversing segment (232) to form a second optical fiber coil (230) with a continuous optical path; The vibration conduction component (300) is arranged at the bottom of the deformable body (100); The rock mass coupling component comprises a coupling base (610) and a coupling connector (620); one side surface of the coupling base (610) is attached to the bottom of the vibration conduction component (300); the coupling connector (620) is arranged on the coupling base (610), and at least part of its connecting portion passes through the other side surface of the coupling base (610) for coupling connection with the rock mass.

2. The vibration sensor for rock fracture monitoring according to claim 1, characterized in that: The deformation body (100) is cylindrical.

3. The vibration sensor for rock fracture monitoring according to claim 1, 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.

4. The vibration sensor for rock fracture monitoring according to claim 1, 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).

5. The vibration sensor for rock mass fracture monitoring according to claim 4, characterized in that: The protective shell (400) is in the shape of an inverted frustum.

6. The vibration sensor for rock fracture monitoring according to claim 4, 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 vibration sensor for rock fracture monitoring according to any one of claims 1 to 6, characterized in that: The coupling connectors (620) are at least three and are distributed in a ring array with the extension line of the axis of the deformable body (100) as the array center line.

8. The vibration sensor for rock mass fracture monitoring according to claim 7, characterized in that: The coupling connection member (620) is a screw or a bolt.

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