A remote real-time monitoring and early warning device and early warning method for gully-type debris flow

Abstract

The present invention relates to a long-distance real-time monitoring and early warning device and an early warning method for gully-type debris flow. It solves the problems of poor stability of debris flow detection devices and insufficient accuracy of monitoring and early warning methods in the prior art. It includes a number of L-shaped mounting rod frames distributed in the gully, a protective base is provided at the bottom of the L-shaped mounting rod frame, the L-shaped mounting rod frame is positioned circumferentially by a plug-in fixing mechanism, and a UWFBG strain sensing mechanism is connected to the lower side of one end of the L-shaped mounting rod frame that is arranged horizontally through a sliding adjustment component, the UWFBG strain sensing mechanism is connected to a controller arranged in the protective base through a UWFBG strain optical fiber that passes through the inner cavity of the L-shaped mounting rod frame, and the controller is connected to a UWFBG demodulator on the early warning platform. The advantages of the present invention are: the device has good stability and the detection method is more accurate.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber early warning, and in particular to a long-distance real-time monitoring and early warning device for gully-type debris flow. Background Art

[0002] Debris flow is a common geological disaster in mountainous areas, with serious hazards, strong suddenness, and rapid disaster speed. It can easily cause serious losses to people's lives, property and infrastructure. It is widely distributed and active. my country's mountainous areas cover a large area, various geological activities are active, and the terrain in mountainous areas is steep. Debris flow is prone to occur under certain rainfall conditions. The existing methods and equipment for monitoring and early warning of debris flow have low scientific and technological content and poor monitoring accuracy. In addition, the debris flow monitoring equipment has the problems of unreliable data transmission, high cost and difficulty in installation, and is easily affected by bad weather on site, and has poor stability. At the same time, the accuracy of the debris flow monitoring method is insufficient, and it is difficult to remotely judge the specific situation of the debris flow.

[0003] In order to solve the shortcomings of the existing technology, people have conducted long-term exploration and proposed various solutions. For example, a Chinese patent document discloses a debris flow early warning sensor device, system and method based on wireless ad hoc network group detection [CN201310685102.7], which includes an RTU and multiple debris flow monitoring and early warning sensor devices, each of which is a MESH network node, and a concentrator for data collection is integrated in the RTU. The RTU is wirelessly connected to all debris flow monitoring and early warning sensor devices through the concentrator.

[0004] The above scheme has solved the problem of poor detection accuracy of debris flow detection and early warning devices in the prior art to a certain extent, but the scheme still has many shortcomings, such as: unreliable data transmission and poor installation stability, and is easily affected by bad weather on site. At the same time, the debris flow monitoring and early warning method is not accurate enough, and it is difficult to remotely judge the specific situation of the debris flow. Summary of the invention

[0005] In view of the above problems, the present invention aims to provide a long-distance real-time monitoring and early warning device for gully-type debris flow with reliable data transmission and good installation stability.

[0006] The purpose of the present invention is to provide a long-distance real-time monitoring and early warning method for gully-type debris flow with good monitoring and early warning method in view of the above problems.

[0007] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a long-distance real-time monitoring and early warning device for valley-type debris flow, comprising a plurality of L-shaped mounting rod frames distributed in the valley, a protective base being provided at the bottom of the L-shaped mounting rod frame, the L-shaped mounting rod frame being positioned circumferentially by a plug-in fixing mechanism, and a UWFBG strain sensing mechanism being connected to the lower side of one end of the L-shaped mounting rod frame being arranged horizontally through a sliding adjustment component, the UWFBG strain sensing mechanism being connected to a controller arranged in the protective base through a UWFBG strain optical fiber passing through the inner cavity of the L-shaped mounting rod frame, and the controller being connected to a UWFBG demodulator on the early warning platform.

[0008] Positioning the L-shaped mounting rod in the plug-in fixing mechanism can effectively ensure the stability of the device and avoid damage caused by bad weather. Secondly, the debris flow detection is carried out through the UWFBG strain sensing mechanism in conjunction with the UWFBG strain optical fiber. It is not only highly sensitive, but also has reliable and fast data transmission. By using the distributed detection method, the detection range is wider, and the flow velocity of the debris flow can be calculated. The data transmission of the UWFBG strain optical fiber is highly reliable, low in cost, and easy to promote.

[0009] In the above-mentioned long-distance real-time monitoring and early warning device for valley-type debris flow, the UWFBG strain sensing mechanism includes a protective outer shell, a strain gauge is loaded in the protective outer shell, and an ultra-weak fiber Bragg grating is pasted on the strain gauge, the ultra-weak fiber Bragg grating is connected to the UWFBG strain optical fiber signal, and the bottom of the protective outer shell has a recessed protective portion, and one end of the strain gauge is pasted with the ultra-weak fiber Bragg grating and exposed to the positioning through hole of the axis of the recessed protective portion.

[0010] The setting of the protective outer shell can effectively protect the strain gauge, and the use of ultra-weak fiber grating can effectively improve the detection sensitivity, the data transmission effect is good, and it is conducive to improving the data transmission speed.

[0011] In the above-mentioned long-distance real-time monitoring and early warning device for valley-type debris flow, the L-shaped mounting rod frame is composed of a transversely arranged mounting cross bar and a longitudinally arranged fixed connecting rod, and the protective outer shell is vertically arranged at one end of the mounting cross bar, the mounting cross bar and the fixed connecting rod are vertically arranged, and a plug-in fixing part is provided at the bottom of the fixed connecting rod, which is plugged into the ground.

[0012] In the above-mentioned long-distance real-time monitoring and early warning device for valley-type debris flows, the sliding adjustment component includes a connecting slide groove arranged at the bottom of the mounting cross bar, and a sliding positioning disc body inserted in the connecting slide groove is provided at one end of the protective outer shell body, the sliding positioning disc body is connected to the protective outer shell body through a connecting rod, auxiliary guide slide grooves parallel to each other are provided on both sides of the connecting slide groove, and sliding connecting blocks corresponding to the auxiliary guide slide grooves are provided on both sides of the sliding positioning disc body, the sliding connecting blocks are slidably inserted in the corresponding auxiliary guide slide grooves, and the length of the auxiliary guide slide groove is the same as the length of the connecting slide groove.

[0013] The setting of the sliding adjustment component can tightly connect the protective outer shell, and can slide and adjust the position as needed, thereby changing the detection position of the strain gauge, and has good flexibility in use.

[0014] In the above-mentioned long-distance real-time monitoring and early warning device for valley-type debris flow, the plug-in fixing mechanism includes a plug-in positioning sleeve arranged on an L-shaped mounting rod frame, a circumferential positioning structure is provided between the circumferential inner wall of the plug-in positioning sleeve and the L-shaped mounting rod frame, and a plurality of fixed connecting parts are plugged into the circumferential outer wall of the plug-in positioning sleeve, the fixed connecting parts are connected to a fixing plate arranged on the ground through an inclined steel wire rope, and the fixing plate is connected to a fixing seat pre-buried in the ground through a fixing screw.

[0015] The arrangement of the plug-in fixing mechanism can not only ensure the installation stability of the L-shaped mounting rod bracket, but also the plug-in installation method is more convenient.

[0016] In the above-mentioned long-distance real-time monitoring and early warning device for valley-type debris flow, a connecting buckle for connecting a steel wire rope is provided on the outer wall of the fixed connecting piece, and a plug-in kit is provided at the upper and lower ends of the fixed connecting piece, a top pressure spring is provided in the middle of the inner cavity of the plug-in kit, and plug-in extensions are provided at both ends of the top pressure spring, and a lifting groove for inserting the plug-in kit is provided at either upper or lower end of the fixed connecting piece, an extrusion spring for extruding the plug-in kit is provided in the lifting groove, a positioning groove for inserting the plug-in kit is provided on the circumferential outer wall of the plug-in positioning sleeve, and fixing grooves for inserting the plug-in kit are provided at the upper and lower ends of the positioning groove, and locking slots for inserting the plug-in extensions are provided on both sides of the fixing groove.

[0017] The plug-in kit and the plug-in extension are respectively plugged into the positioning groove and the locking groove, so that the fixed connection piece can be tightly connected to the plug-in positioning sleeve, thereby improving the connection tightness.

[0018] In the above-mentioned long-distance real-time monitoring and early warning device for valley-type debris flow, the circumferential positioning structure includes a plurality of accommodating grooves arranged around the L-shaped mounting rod frame, an elastic locking member is arranged in the accommodating groove, and the two ends of the elastic locking member are arranged in an arc shape, and the circumferential inner wall of the plug-in positioning sleeve is provided with a plurality of strip-shaped locking slots arranged corresponding to the elastic locking member, and the plug-in positioning sleeve is locked on the L-shaped mounting rod frame by mutual plugging of the elastic locking member and the strip-shaped locking slots, and an annular positioning groove is arranged on the L-shaped mounting rod frame and at both ends of the accommodating groove, and an annular locking rubber ring is arranged corresponding to the annular positioning groove on the circumferential inner wall of the plug-in positioning sleeve and at both ends of the strip-shaped locking slot. Such a connection method can form circumferential positioning between the plug-in positioning sleeve and the L-shaped mounting rod frame, and the upper and lower positions are fixed.

[0019] According to the above-mentioned long-distance real-time monitoring and early warning device for gully-type debris flow, a long-distance real-time monitoring and early warning method for gully-type debris flow is provided, and the method comprises the following steps:

[0020] S1. Plan the installation location based on local hydrological data and field investigation;

[0021] S2. Install the L-shaped mounting rod bracket at the pre-planned mounting point and position it using a plug-in fixing mechanism;

[0022] S3, select UWFBG strain fiber and calibrate the ultra-weak fiber grating points;

[0023] S4, connecting the calibrated ultra-weak optical fiber to the strain gauge to form a UWFBG strain sensing mechanism;

[0024] S5, connect all arranged UWFBG strain sensing mechanisms in series and to the UWFBG demodulator for real-time monitoring;

[0025] S6. The velocity and flow rate of the debris flow are calculated by the interval distance and time difference between the UWFBG strain sensing mechanisms, and the change is calculated by the drift and curvature of the Bragg grating center wavelength of the UWFBG strain optical fiber.

[0026] In the above-mentioned long-distance real-time monitoring and early warning method for gully-type debris flow, the UWFBG strain sensing mechanism senses the debris flow through the strain size of the UWFBG strain optical fiber, and locates the location of the debris flow through the UWFBG strain optical fiber. At the same time, the velocity and flow of the debris flow are calculated through the pre-set interval distance and time difference between each UWFBG strain sensing mechanism;

[0027] The calculation formula of debris flow velocity is: Wherein, S represents the distance between two adjacent UWFBG strain sensing mechanisms, and t represents the sensing time difference between two adjacent UWFBG strain sensing mechanisms 4 .

[0028] In the above-mentioned long-distance real-time monitoring and early warning method for gully-type debris flow, the method of using the UWFBG strain sensor mechanism to detect the occurrence of debris flow is: using the relationship between the drift and curvature of the Bragg grating center wavelength of the UWFBG strain fiber to reconstruct the linear deformation:

[0029] The calculation formula for the central wavelength of the grating reflection spectrum is: B =2n eff Λ, where λ B represents the central wavelength of the grating reflection spectrum, n eff represents the effective refractive index at the core, ∧ represents the grating period;

[0030] The principle is that the central wavelength of the Bragg grating of the UWFBG strained fiber is related to the grating period and the effective refractive index of the fiber core. When the changes in external physical quantities cause the changes in the grating period and the effective refractive index of the fiber core, the central wavelength of the Bragg grating of the UWFBG strained fiber will drift.

[0031] The calculation formula for the change in the Bragg grating center wavelength 7 of the UWFBG strained fiber is: △λ B =2△n eff Λ+2n eff △Λ, where Δλ B Indicates the change in the Bragg center wavelength of the UWFBG strained fiber, Δn eff It represents the change of effective refractive index of the grating core caused by elastic-optic effect or thermo-optic effect, and Δ∧ represents the change of grating period caused by thermal expansion effect or axial stress strain;

[0032] When the axial stress strain and temperature change, the calculation formula for the change in the Bragg grating center wavelength of the UWFBG strained fiber is: When the temperature is constant and the axial stress and strain change, the calculation formula for the change in the Bragg grating center wavelength of the UWFBG strained fiber is:

[0033] By calibrating the ultra-weak fiber Bragg grating and the strain gauge to form a UWFBG strain sensing mechanism, the debris flow is monitored in real time, and the different strains of the strain gauge are used to judge the debris flow. The ultra-low reflectivity of the UWFBG strain fiber is used to increase the capacity, connect a large number of UWFBG strain sensing mechanisms, and improve the accuracy of early warning. At the same time, the positioning capability of the UWFBG strain fiber can accurately determine the location of the debris flow, and the interval distance and time difference between the UWFBG strain sensing mechanisms can be used to calculate the velocity and flow of the debris flow. The detection accuracy is good, and the calculation results are more accurate, which can realize remote judgment of the specific situation of the debris flow.

[0034] Compared with the existing technology, the advantages of the present invention are: a large number of UWFBG strain sensing mechanisms arranged in the valley are connected by the large capacity of UWFBG strain optical fiber, so as to improve the detection accuracy, and the position of the debris flow is located by using the UWFBG strain optical fiber positioning, and the flow velocity and flow rate of the debris flow are calculated by the interval distance and time difference between the UWFBG strain sensing mechanisms, so as to facilitate timely understanding of the specific situation of the debris flow; at the same time, the L-shaped mounting rod frame installed with the UWFBG strain sensing mechanism is fixed by using a plug-in fixing mechanism to ensure the stability of the UWFBG strain sensing mechanism and avoid collapse and damage caused by bad weather. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the structure after the L-shaped mounting rod bracket of the present invention is installed;

[0036] Figure 2 It is a schematic diagram of the plug-in positioning sleeve structure in the invention;

[0037] Figure 3 It is a partial schematic diagram of the circumferential positioning structure in the present invention;

[0038] Figure 4 It is a schematic diagram of the structure of the fixed connection member in the present invention;

[0039] Figure 5 It is a schematic diagram of the protective outer shell structure in the present invention;

[0040] Figure 6 It is a schematic diagram of the local structure of the installation cross bar in the present invention;

[0041] Figure 7 It is a local structure connection block diagram in the present invention;

[0042] Figure 8 It is a schematic diagram of the present invention;

[0043] In the figure: L-shaped mounting rod frame 1, protective base 11, mounting cross bar 12, fixing connecting rod 13, plug-in fixing part 14, plug-in fixing mechanism 2, plug-in positioning sleeve 21, positioning groove 211, fixing groove 212, locking card groove 213, fixing connecting piece 22, connecting buckle 221, plug-in kit 222, top pressure spring 223, plug-in extension part 224, lifting slide 225, extrusion spring 226, wire rope 23, fixing plate 24, fixing seat 25, sliding adjustment component 3, connecting slide 31, sliding positioning disc 32, connecting Rod 33, auxiliary guide slot 34, sliding connection block 35, UWFBG strain sensing mechanism 4, UWFBG strain optical fiber 41, controller 42, protective outer shell 43, recessed protection part 431, positioning through hole 432, strain gauge 44, ultra-weak fiber grating 45, early warning platform 5, UWFBG demodulator 51, circumferential positioning structure 6, accommodating groove 61, elastic locking member 62, strip locking slot 63, annular positioning groove 64, annular locking rubber ring 65, Bragg grating central wavelength 7, fiber core 71, grating 72. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] like Figure 1 , Figure 8As shown, a long-distance real-time monitoring and early warning device for gully-type debris flow comprises a plurality of L-shaped mounting rod frames 1 distributed in the gully, a protective base 11 being provided at the bottom of the L-shaped mounting rod frame 1, the L-shaped mounting rod frame 1 being positioned circumferentially by a plug-in fixing mechanism 2, and a UWFBG strain sensing mechanism 4 being connected to the lower side of one end of the L-shaped mounting rod frame 1 being arranged horizontally through a sliding adjustment component 3, the UWFBG strain sensing mechanism 4 being connected to a controller 42 arranged in the protective base 11 through a UWFBG strain optical fiber 41 penetrating through the inner cavity of the L-shaped mounting rod frame 1, and the controller 42 being connected to a UWFBG demodulator 51 on the early warning platform 5.

[0046] The plug-in fixing mechanism 2 is used to ensure the stability of the L-shaped mounting rod frame 1 to avoid collapse caused by bad weather. The sliding adjustment component 3 is used to slide and adjust the detection position of the UWFBG strain sensing mechanism 4, and the UWFBG strain optical fiber 41 is used for positioning and data transmission. The controller compares the preset variables with the actually detected variables, and when the detected strain data variables exceed the preset variables, an alarm is issued to the early warning platform 5. The UWFBG demodulator 51 is used for wavelength and grating measurement.

[0047] The UWFBG strain sensing mechanism 4 includes a protective outer shell 43, a strain gauge 44 is loaded in the protective outer shell 43, and an ultra-weak fiber Bragg grating 45 is pasted on the strain gauge 44, the ultra-weak fiber Bragg grating 45 is connected to the UWFBG strain optical fiber 41 by signal, and the bottom of the protective outer shell 43 has a recessed protective portion 431, and one end of the strain gauge 44 is pasted with the ultra-weak fiber Bragg grating 45 and exposed to the positioning through hole 432 of the axis of the recessed protective portion 431. The UWFBG strain sensing mechanism 4 uses the strain gauge 44 and the calibrated ultra-weak fiber Bragg grating 45 to detect the strain of the debris flow, and the recessed protective portion 431 is used to protect the ultra-weak fiber Bragg grating 45 and the end of the strain gauge to avoid being invaded by rainwater.

[0048] In detail, the L-shaped mounting rod frame 1 is composed of a transversely arranged mounting cross bar 12 and a longitudinally arranged fixed connecting rod 13, and the protective outer shell 43 is vertically arranged at one end of the mounting cross bar 12, the mounting cross bar 12 and the fixed connecting rod 13 are vertically arranged, and a plug-in fixing part 14 is provided at the bottom of the fixed connecting rod 13, and the plug-in fixing part 14 is plugged into the ground.

[0049] like Figure 5-6As shown, the sliding adjustment assembly 3 includes a connecting groove 31 arranged at the bottom of the mounting cross bar 12, and a sliding positioning disc 32 inserted into the connecting groove 31 is provided at one end of the protective outer shell 43, and the sliding positioning disc 32 is connected to the protective outer shell 43 through a connecting rod 33, and auxiliary guide grooves 34 parallel to each other are provided on both sides of the connecting groove 31, and sliding connecting blocks 35 corresponding to the auxiliary guide grooves 34 are provided on both sides of the sliding positioning disc 32, and the sliding connecting blocks 35 are slidably inserted in the corresponding auxiliary guide grooves 34, and the length of the auxiliary guide grooves 34 is the same as the length of the connecting groove 31.

[0050] The auxiliary guide slot 34 has a sliding guide function, and the sliding connection with the sliding connection block 35 is used to ensure the connection stability between the protective outer shell 43 and the mounting cross bar 12, and the sliding positioning disc 32 and the connecting rod 33 have a cavity for the UWFBG strain fiber 41 to pass through.

[0051] like Figure 1-3 As shown, the plug-in fixing mechanism 2 includes a plug-in positioning sleeve 21 arranged on the L-shaped mounting rod frame 1, a circumferential positioning structure 6 is arranged between the circumferential inner wall of the plug-in positioning sleeve 21 and the L-shaped mounting rod frame 1, and a plurality of fixed connectors 22 are plugged into the circumferential outer wall of the plug-in positioning sleeve 21, and the fixed connectors 22 are connected to a fixed plate 24 arranged on the ground through an inclined steel wire rope 23, and the fixed plate 24 is connected to a fixed seat 25 pre-buried in the ground through a fixed screw. The pre-buried depth of the fixed seat 25 is the same as the plug-in depth of the plug-in fixing part 14 to avoid tilting.

[0052] Among them, the outer wall of the fixed connecting piece 22 is provided with a connecting buckle 221 for connecting the wire rope 23, and the upper and lower ends of the fixed connecting piece 22 are provided with a plug-in kit 222, a top pressure spring 223 is provided in the middle of the inner cavity of the plug-in kit 222, and plug-in extensions 224 are provided at both ends of the top pressure spring 223, and a lifting slide groove 225 for inserting the plug-in kit 222 is provided at any upper or lower end of the fixed connecting piece 22, and an extrusion spring 226 for extruding the plug-in kit 222 is provided in the lifting slide groove 225, and a positioning groove 211 for inserting the plug-in kit 222 is provided on the circumferential outer wall of the plug-in positioning sleeve 21, and the upper and lower ends of the positioning groove 211 are provided with fixing grooves 212 for inserting the plug-in kit 222, and locking card grooves 213 are provided on both sides of the fixing groove 212 for inserting the plug-in extension 224.

[0053] During installation, the fixed connector 22 is inserted into the positioning groove 211, and the plug-in kit 222 is inserted into the fixed groove 212 by the action of the extrusion spring 226, and the plug-in extension part 224 is inserted into the locking groove 213 by the action of the pressing spring 223, thereby achieving locking.

[0054] In detail, the circumferential positioning structure 6 includes a plurality of accommodating grooves 61 arranged around the L-shaped mounting rod frame 1, an elastic locking member 62 is arranged in the accommodating groove 61, and the two ends of the elastic locking member 62 are arranged in an arc shape, and the circumferential inner wall of the plug-in positioning sleeve 21 is provided with a plurality of strip locking slots 63 arranged corresponding to the elastic locking member 62, and the plug-in positioning sleeve 21 is locked on the L-shaped mounting rod frame 1 by the mutual plug-in connection between the elastic locking member 62 and the strip locking slots 63, and annular positioning grooves 64 are provided on the L-shaped mounting rod frame 1 and at the upper and lower ends of the accommodating grooves 61, and annular locking rubber rings 65 arranged corresponding to the annular positioning grooves 64 are provided on the circumferential inner wall of the plug-in positioning sleeve 21 and at the upper and lower ends of the strip locking slots 63.

[0055] The circumferential positioning structure 6 is used to circumferentially lock the plug-in positioning sleeve 21 and to position the longitudinal position.

[0056] A method for long-distance real-time monitoring and early warning of gully-type debris flow, the method comprising the following steps:

[0057] S1. Plan the installation location based on local hydrological data and field investigation;

[0058] S2, installing the L-shaped mounting rod frame 1 at the pre-planned mounting point and positioning it using the plug-in fixing mechanism 2;

[0059] S3, select the UWFBG strain fiber 41 and calibrate the ultra-weak fiber grating point;

[0060] S4, connecting the calibrated ultra-weak optical fiber to the strain gauge 44 to form a UWFBG strain sensing mechanism 4;

[0061] S5, connecting all arranged UWFBG strain sensing mechanisms 4 in series and to the UWFBG demodulator 51 for real-time monitoring;

[0062] S6. Calculate the velocity and flow rate of the debris flow through the interval distance and time difference between the UWFBG strain sensing mechanisms 4, and calculate the variation through the drift and curvature of the Bragg grating center wavelength 7 of the UWFBG strain optical fiber 41.

[0063] like Figure 8 As shown, the UWFBG strain sensing mechanism 4 senses the debris flow through the strain size of the UWFBG strain optical fiber 41, and locates the location of the debris flow through the UWFBG strain optical fiber 41. At the same time, the velocity and flow rate of the debris flow are calculated through the pre-set interval distance and time difference between each UWFBG strain sensing mechanism 4;

[0064] The calculation formula of debris flow velocity is: Wherein, S represents the distance between two adjacent UWFBG strain sensing mechanisms 4 , and t represents the sensing time difference between two adjacent UWFBG strain sensing mechanisms 4 .

[0065] Preferably, the method of using the UWFBG strain sensing mechanism 4 to detect the occurrence of debris flow is to reconstruct the linear deformation using the relationship between the drift and curvature of the Bragg grating center wavelength 7 of the UWFBG strain optical fiber 41:

[0066] The calculation formula for the central wavelength of the grating reflection spectrum is: B =2n eff Λ, where λ B represents the central wavelength of the grating reflection spectrum, n eff represents the effective refractive index at the core 71, ∧ represents the grating period;

[0067] The principle is that the Bragg grating center wavelength 7 of the UWFBG strained fiber 41 is related to the period of the grating 72 and the effective refractive index of the core 71. When the change of external physical quantity causes the period of the grating 72 and the effective refractive index of the core 71 to change, the Bragg grating center wavelength 7 of the UWFBG strained fiber 41 will drift.

[0068] The calculation formula for the change in the Bragg grating center wavelength 7 of the UWFBG strained fiber 41 is: △λ B =2△n eff Λ+2n eff △Λ, where Δλ B represents the change in the Bragg center wavelength of the UWFBG strain fiber 41, Δn eff represents the change of the effective refractive index of the grating core 71 caused by the elastic-optic effect or the thermo-optic effect, and Δ∧ represents the change of the grating period caused by the thermal expansion effect or the axial stress strain;

[0069] When the axial stress strain and temperature change, the calculation formula for the change of the Bragg grating center wavelength 7 of the UWFBG strain fiber 41 is: When the temperature is constant and the axial stress and strain change, the calculation formula for the change in the Bragg grating center wavelength 7 of the UWFBG strained optical fiber 41 is:

[0070] Among them, ① is the detection principle diagram, ② is the wavelength trend diagram of the incident light, ③ is the wavelength trend diagram of the reflected light, and ④ is the wavelength trend diagram of the transmitted light passing through the grid area core 71. The wavelength change of the transmitted light is caused by temperature and strain.

[0071] In summary, the principle of this embodiment is: by arranging a large number of L-shaped mounting rods 1 equipped with WFBG strain sensing mechanisms 4 in the valley, using calibrated ultra-weak fiber gratings 45 and strain gauges 44 to detect strain and temperature of the environment, and using UWFBG strain optical fiber 41 to transmit data and locate the position, the data transmitted to the early warning platform 5 is mediated by the UWFBG demodulator 51, and the central wavelength of the grating reflection spectrum and the change amount of the Bragg grating central wavelength 7 of the UWFBG strain optical fiber 41 are calculated according to the mediated wavelength, so as to accurately judge the debris flow, and locate the debris flow position through the positioning characteristics of the UWFBG strain optical fiber 41, and the flow velocity and flow rate of the debris flow are calculated through the interval distance and time difference between each UWFBG strain sensing mechanism 4, so as to timely understand the specific situation of the debris flow; wherein, the L-shaped mounting rod 1 is circumferentially positioned by the plug-in fixing mechanism 2 to ensure the stability of the UWFBG strain sensing mechanism 4.

[0072] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0073] Although this article uses more L-shaped mounting rod frame 1, protective base 11, mounting cross bar 12, fixed connecting rod 13, plug-in fixing part 14, plug-in fixing mechanism 2, plug-in positioning sleeve 21, positioning groove 211, fixing groove 212, locking card slot 213, fixed connector 22, connecting buckle 221, plug-in kit 222, top pressure spring 223, plug-in extension part 224, lifting slide 225, extrusion spring 226, wire rope 23, fixing plate 24, fixing seat 25, sliding adjustment component 3, connecting slide 31, sliding positioning disc 32, connecting rod 33, auxiliary The terms such as guide slot 34, sliding connection block 35, UWFBG strain sensing mechanism 4, UWFBG strain optical fiber 41, controller 42, protective outer shell 43, recessed protection part 431, positioning through hole 432, strain gauge 44, ultra-weak fiber grating 45, early warning platform 5, UWFBG demodulator 51, circumferential positioning structure 6, accommodating groove 61, elastic locking member 62, strip locking slot 63, annular positioning groove 64, annular locking rubber ring 65, Bragg grating central wavelength 7, fiber core 71, grating 72, etc., but the possibility of using other terms is not excluded. The use of these terms is only for more convenient description and explanation of the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A long-distance real-time monitoring and early warning device for gully-type debris flow, comprising a plurality of L-shaped mounting rods (1) distributed in the gully, wherein a protective base (11) is provided at the bottom of the L-shaped mounting rods (1), characterized in that: The L-shaped mounting rod frame (1) is positioned in the circumferential direction by a plug-in fixing mechanism (2), and a UWFBG strain sensing mechanism (4) is connected to the lower side of one end of the L-shaped mounting rod frame (1) which is arranged in a transverse direction through a sliding adjustment component (3). The UWFBG strain sensing mechanism (4) is connected to a controller (42) arranged in the protective base (11) through a UWFBG strain optical fiber (41) passing through the inner cavity of the L-shaped mounting rod frame (1), and the controller (42) is connected to the UWFBG strain sensing mechanism (42) on the early warning platform (5). The plug-in fixing mechanism (2) comprises a plug-in positioning sleeve (21) arranged on the L-shaped mounting rod frame (1), a circumferential positioning structure (6) is arranged between the circumferential inner wall of the plug-in positioning sleeve (21) and the L-shaped mounting rod frame (1), and a plurality of fixed connecting members (22) are plugged into the circumferential outer wall of the plug-in positioning sleeve (21), and the fixed connecting members (22) are connected to a fixing plate (24) arranged on the ground through an inclined steel wire rope (23), and the fixing plate (24) ) is connected to a fixing seat (25) pre-buried in the ground through a fixing screw; the outer wall of the fixing connecting piece (22) is provided with a connecting buckle (221) for connecting the steel wire rope (23), and the upper and lower ends of the fixing connecting piece (22) are provided with a plug-in kit (222), a top pressure spring (223) is provided in the middle of the inner cavity of the plug-in kit (222), and both ends of the top pressure spring (223) are provided with plug-in extension parts (224), and any upper and lower ends of the fixing connecting piece (22) are provided with a plug-in kit (222) for plugging The lifting and lowering slide groove (225) is provided with an extrusion spring (226) that can extrude the plug-in kit (222); the plug-in positioning sleeve (21) is provided with a positioning groove (211) on the circumferential outer wall for the plug-in kit (222) to be inserted, and the upper and lower ends of the positioning groove (211) are provided with fixing grooves (212) for the plug-in kit (222) to be inserted, and the fixing groove (212) has locking grooves (213) on both sides for the plug-in extension part (224) to be inserted.

2. A long-distance real-time monitoring and early warning device for gully-type debris flow according to claim 1, characterized in that: The UWFBG strain sensing mechanism (4) comprises a protective outer shell (43), a strain gauge (44) is loaded inside the protective outer shell (43), and an ultra-weak fiber grating (45) is pasted on the strain gauge (44), the ultra-weak fiber grating (45) is signal-connected to the UWFBG strain optical fiber (41), and the bottom of the protective outer shell (43) has a recessed protective portion (431), and one end of the strain gauge (44) is pasted with the ultra-weak fiber grating (45) and exposed to the positioning through hole (432) at the axis of the recessed protective portion (431).

3. A long-distance real-time monitoring and early warning device for gully-type debris flow according to claim 2, characterized in that: The L-shaped mounting rod frame (1) is composed of a transversely arranged mounting cross bar (12) and a longitudinally arranged fixed connecting rod (13), and the protective outer shell (43) is vertically arranged at one end of the mounting cross bar (12), the mounting cross bar (12) and the fixed connecting rod (13) are vertically arranged, and a plug-in fixing portion (14) is provided at the bottom of the fixed connecting rod (13), and the plug-in fixing portion (14) is plugged into the ground.

4. A long-distance real-time monitoring and early warning device for gully-type debris flow according to claim 3, characterized in that: The sliding adjustment component (3) includes a connecting groove (31) arranged at the bottom of the mounting cross bar (12), and a sliding positioning disc (32) inserted into the connecting groove (31) is provided at one end of the protective outer shell (43), and the sliding positioning disc (32) is connected to the protective outer shell (43) through a connecting rod (33), and auxiliary guide grooves (34) parallel to each other are provided on both sides of the connecting groove (31), and sliding connection blocks (35) corresponding to the auxiliary guide grooves (34) are provided on both sides of the sliding positioning disc (32), and the sliding connection blocks (35) are slidably inserted in the corresponding auxiliary guide grooves (34), and the length of the auxiliary guide grooves (34) is the same as the length of the connecting groove (31).

5. The long-distance real-time monitoring and early warning device for gully-type debris flow according to claim 1 is characterized in that: The circumferential positioning structure (6) comprises a plurality of accommodating grooves (61) arranged in the circumference of the L-shaped mounting rod frame (1), an elastic locking member (62) is arranged in the accommodating groove (61), and the two ends of the elastic locking member (62) are arranged in an arc shape, the circumferential inner wall of the plug-in positioning sleeve (21) is provided with a plurality of strip-shaped locking slots (63) arranged corresponding to the elastic locking member (62), the plug-in positioning sleeve (21) is locked on the L-shaped mounting rod frame (1) by mutual plugging and locking of the elastic locking member (62) and the strip-shaped locking slots (63), annular positioning grooves (64) are arranged on the L-shaped mounting rod frame (1) and at the upper and lower ends of the accommodating grooves (61), and annular locking rubber rings (65) are arranged corresponding to the annular positioning grooves (64) on the circumferential inner wall of the plug-in positioning sleeve (21) and at the upper and lower ends of the strip-shaped locking slots (63).

6. A method for long-distance real-time monitoring and early warning of gully-type debris flow according to a long-distance real-time monitoring and early warning device for gully-type debris flow according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: S1. Plan the installation location based on local hydrological data and field investigation; S2, installing the L-shaped mounting rod frame (1) at the pre-planned mounting point and positioning it using a plug-in fixing mechanism (2); S3, selecting the UWFBG strain fiber (41) and calibrating the ultra-weak fiber grating points; S4, connecting the calibrated ultra-weak optical fiber to the strain gauge (44) to form a UWFBG strain sensing mechanism (4); S5, connecting all arranged UWFBG strain sensing mechanisms (4) in series and to a UWFBG demodulator (51) for real-time monitoring; S6. Calculate the velocity and flow rate of the debris flow through the interval distance and time difference between the UWFBG strain sensing mechanisms (4), and calculate the change through the drift and curvature of the Bragg grating center wavelength (7) of the UWFBG strain optical fiber (41).

7. A method for long-distance real-time monitoring and early warning of gully-type debris flow according to claim 6, characterized in that: The UWFBG strain sensing mechanism (4) senses the debris flow through the strain of the UWFBG strain optical fiber (41), and locates the location where the debris flow occurs through the UWFBG strain optical fiber (41), and at the same time, calculates the velocity and flow of the debris flow through the pre-set interval distance and time difference between each UWFBG strain sensing mechanism (4); The calculation formula of debris flow velocity is: Wherein, S represents the spacing distance between two adjacent UWFBG strain sensing mechanisms (4), and t represents the sensing time difference between two adjacent UWFBG strain sensing mechanisms (4).

8. A method for long-distance real-time monitoring and early warning of gully-type debris flow according to claim 7, characterized in that: The UWFBG strain sensing mechanism (4) detects the occurrence of debris flow by reconstructing the linear deformation using the relationship between the drift and curvature of the Bragg grating center wavelength (7) of the UWFBG strain optical fiber (41): The calculation formula for the central wavelength of the grating reflection spectrum is: B =2n eff Λ, where λ B represents the central wavelength of the grating reflection spectrum, n eff represents the effective refractive index at the core (71), ∧ represents the grating period; The principle is that the central wavelength (7) of the Bragg grating of the UWFBG strained optical fiber (41) is related to the period of the grating (72) and the effective refractive index of the core (71). When the change of external physical quantities causes the period of the grating (72) and the effective refractive index of the core (71) to change, the central wavelength (7) of the Bragg grating of the UWFBG strained optical fiber (41) will drift. The calculation formula for the change in the Bragg grating center wavelength (7) of the UWFBG strained optical fiber (41) is: △λ B =2△n eff Λ+2n eff △Λ, where Δλ B represents the change in the Bragg center wavelength of the UWFBG strained fiber (41), Δn eff represents the change of the effective refractive index of the grating region core (71) caused by the elastic-optic effect or the thermo-optic effect, and Δ∧ represents the change of the grating period caused by the thermal expansion effect or the axial stress strain; When the axial stress strain and temperature change, the calculation formula for the change of the Bragg grating center wavelength (7) of the UWFBG strained optical fiber (41) is: When the temperature is constant and the axial stress and strain change, the calculation formula for the change in the Bragg grating center wavelength (7) of the UWFBG strained optical fiber (41) is:

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