Application and use method of optical fiber for predicting roof fall in roadway

Abstract

The application provides an application and a use method of optical fiber for predicting roadway roof collapse, and relates to the technical field of optical fiber, and comprises the following steps: fixing optical fiber on a roadway roof along a direction of the roadway; when surrounding rock on the roadway roof is displaced and falls, an optical fiber mutation point is generated at a falling position of the optical fiber; position information of the optical fiber mutation point is acquired by using an optical fiber output device; change information of the roadway roof is obtained by analyzing the position information of the optical fiber mutation point; when any parameter in the change information is not in a preset normal threshold value, the falling position of the roadway is reinforced; and falling position information of the roadway is obtained by analyzing the change information of the roadway roof. The application can timely find problems such as surrounding rock displacement and falling by monitoring stress and strain information of the roadway roof in real time through the optical fiber output device, improves the monitoring effect on the safety of the roadway, and can accurately determine the position where the roadway roof changes by using the position information of the optical fiber mutation point.

Description

TECHNICAL FIELD

[0001] The application relates to the field of optical fiber related technology, in particular to an application and use method of optical fiber for predicting roadway roof collapse. BACKGROUND

[0002] With the rapid development of roadway engineering construction technology and design theory, more and more roads, railways, subways and the like are built. Roadway deformation stability and roadway engineering safety are closely related to each other, and the main performance of roadway engineering accidents is roadway instability, and thus various safety production accidents are often caused, and roadway collapse accidents are the most common roadway safety accidents. Due to the characteristics of roadway engineering, once a collapse accident occurs, serious personnel casualties and economic losses are often caused. This makes it more and more important to monitor roadway deformation.

[0003] At present, in the process of monitoring the roadway roof, mechanical monitoring equipment is usually arranged in the separation layer of the roadway roof, which can monitor the collapse of the roadway roof, but has some shortcomings, mainly including the inability to realize automatic continuous monitoring of the separation layer of the roof and data transmission, and the inability to well warn the collapse of the roof, which constitutes a potential hidden danger to the safety of the roadway. Therefore, it is necessary to provide an application and use method of optical fiber for predicting roadway roof collapse to solve the above technical problems. SUMMARY

[0004] The application provides an application and use method of optical fiber for predicting roadway roof collapse, which solves the problems of the inability to realize automatic continuous monitoring of the separation layer of the roof and data transmission, and the inability to well warn the collapse of the roof.

[0005] To solve the above technical problems, the application provides an application and use method of optical fiber for predicting roadway roof collapse, which comprises the following steps: fixing optical fiber on the roadway roof along the direction of the roadway;

[0006] When the surrounding rock on the roadway roof is displaced and the gangue falls, the optical fiber generates an optical fiber mutation point at the falling position; the position information of the optical fiber mutation point is acquired by using an optical fiber output device; the change information of the roadway roof is obtained by analyzing the position information of the optical fiber mutation point, and when any parameter in the change information is not in a preset normal threshold value, the roadway collapse position is reinforced; the prediction of the roadway collapse position information is obtained by analyzing the change information of the roadway roof.

[0007] As a preferred embodiment of the application, the position information of the optical fiber mutation point is acquired by using an optical fiber output device, and specifically comprises the following steps:

[0008] The stress and strain information of the roadway roof is acquired in real time by the optical fiber, and the stress and strain information of the roadway roof is sent to a roadway monitoring center by the optical fiber output device and stored; the stress and strain information of the roadway roof is received by the roadway monitoring center and analyzed, processed and interpreted, the influence of temperature is eliminated by using the linear relationship between the frequency shift of the Brillouin backscattering light and the strain and temperature, and the position information of the optical fiber mutation point is obtained; wherein the stress and strain information includes the frequency shift of the Brillouin backscattering light, the strain distribution and the temperature distribution in the radial direction of the roadway roof.

[0009] The specific relationship in the above is that the linear relationship between the frequency shift of the Brillouin backscattering light and the strain and temperature is represented as The relationship between the frequency shift of the temperature compensation optical fiber and temperature is The frequency shift and strain relationship after eliminating the influence of temperature is Gx(ε,0)=Gx(ε,T)-Gx(0,T); and finally the position information of the optical fiber mutation point is obtained Wherein Gx(ε,T) represents the frequency shift of the Brillouin backscattering light under the action of strain and temperature, α and β represent the proportional constant corresponding to strain and temperature, δ represents the temperature compensation constant, and ε and T represent the strain distribution and the temperature distribution in the radial direction of the roadway roof, respectively.

[0010] As a preferred embodiment of the present application, the change information of the roadway roof is obtained by analyzing the position information of the optical fiber mutation point, and the specific analysis is as follows:

[0011] The position of the outer edge of the surrounding rock on the roadway roof is taken as the starting point, the frequency shift of the Brillouin backscattering light in the stress and strain information acquired from the optical fiber output device, and the strain distribution ε in the radial direction of the roadway roof are used, and the continuous random variable variance calculation formula is used for operation To obtain the deformation value in the radial direction of the roadway roof; wherein Sj represents the deformation value at j of the outer edge of the surrounding rock of the roadway roof, and dz represents a small length element along the radial direction of the surrounding rock of the roadway roof.

[0012] The deformation values of the roadway roof in a plurality of preset time zones before the current time are acquired, a deformation plane coordinate system of each preset time zone is constructed, the deformation values in the preset time zone are substituted into the deformation plane coordinate system according to the acquisition time, the position of the deformation values in the deformation plane coordinate system is marked as a deformation point, two deformation points spaced by one deformation point are connected to obtain an auxiliary line, a triangle is formed by the two deformation lines and the auxiliary line, and the area of the triangle is calculated; the area of the triangle above the auxiliary line is marked as an ascending triangle value, and the area of the triangle below the auxiliary line is marked as a descending triangle value; the sum of all the ascending triangle values is taken to obtain an ascending average value B1, and the sum of all the descending triangle values is taken to obtain a descending average value B2; the ascending average value and the descending average value are calculated, and a formula B=B1*b1+B2*b2 is used to obtain the change value of the roadway roof in the radial direction; wherein b1 and b2 represent proportional constants corresponding to the ascending average value and the descending average value, respectively; and the deformation value and the change value of the roadway roof in the radial direction are marked as change information.

[0013] The vibration information of the outer edge of the surrounding rock on the roadway roof is acquired, the vibration information includes the vibration frequency of the outer edge of the surrounding rock, Fourier analysis is performed on the vibration information, the vibration information is converted into frequency values by using discrete Fourier transform, a preset threshold value of the frequency values is set and compared, if the frequency values are in the preset threshold value, the roadway roof is normal, and if the frequency values are not in the preset threshold value, there is gangue falling on the roadway roof; when the gangue falls, the falling speed of the gangue is acquired, the falling time of the gangue is marked as an initial falling time, the time difference between the current time and the initial falling time is calculated to obtain a falling time difference, the falling time difference is divided into a plurality of falling time zones according to equal time, the falling acceleration of the falling time zone is calculated, and the acceleration of the gangue is calculated by using the falling accelerations of the plurality of falling time zones.

[0014] As a preferred embodiment of the present application, the roadway monitoring center further comprises a prediction model unit and a model application unit; the prediction model unit uses a MATLAB neural network tool to select the deformation values and the change values of a specified number of preset time zones before the current time, the corresponding acquisition times and the acceleration information of the gangue, and accordingly generates a deformation model and a change model based on ANFIS through an ANFIS function;

[0015] The model application unit inputs the prediction time zone to obtain the deformation prediction value Sn+m of the prediction time zone; and inputs the prediction time zone to obtain a predicted value Bn+m of the change of the predicted time zone; wherein preset time zones are marked as t0, t1, t2, t3...tn, a predicted time length is obtained by using a formula t1-t0=t2-t1=...=tn-tn-1=▽t, t0 represents an initial preset time zone in all preset time zones before the current time, tn represents a preset time zone where the current time is located, m represents a number of preset time zones selected for predicting the deformation value and the change value in the radial direction of the roof of the roadway, and m is a positive number, and m▽t represents the preset time zones accumulated in the number m and marked as the predicted time zone; a normal threshold value of the deformation value and the change value is set as Sz and Bz in combination with a specific engineering object, the specific engineering object includes but is not limited to stress, strain, support structure deformation, rock wall stability and the like in the roadway, the deformation prediction value and the change prediction value are compared with the corresponding normal threshold value, if Sn+m≤Sz and Bn+m≤Bz, no treatment is performed, and if any one of Sn+m>Sz or Bn+m>Bz, position information of the fiber abrupt change point at this moment is marked as predicted roadway collapse position information and the position is subjected to reinforced support treatment.

[0016] As a preferred embodiment of the present application, the roadway monitoring center further comprises a prediction readjustment module; the prediction readjustment module is used to adjust a specified number of preset time zones before the current time selected by the ANFIS function to perform verification analysis, and specifically:

[0017] When any one parameter in the change information is not in the preset normal threshold value, the specified number of preset time zones before the current time selected by the ANFIS function is adjusted, the specified number is adjusted by weighting, the adjusted specified number is obtained by preset number calculation of the specified number, and the above is repeated until the number of the adjusted specified number reaches a preset number threshold value;

[0018] The deformation value and the change value of the adjusted specified number of preset time zones before the current time are used to adjust the deformation model and the change model based on the ANFIS in combination with the corresponding collection time; the prediction time zone is re-input to the adjusted deformation model and the change model based on the ANFIS to generate a re-measured deformation prediction value S i n+m and a re-measured change prediction value B i n+m, i represents the number of times of weighting adjustment of the specified number; all re-measured deformation prediction values S i n+m and re-measured change prediction values B i n+m are compared with the normal threshold values of the deformation value and the change value respectively, and the number of Sin+m≤Sz and B i n+m≤Bz is marked as not in number, and any one of Sin+m>Sz or B iThe number of n+m>Bz is marked as a number to be processed; the product of the non-processed number and the required number and the corresponding weight is summed to obtain a processing value; the processing value is compared with a preset processing threshold value, if it is in the preset processing threshold value, the position information of the fiber mutation point is marked as the predicted roadway collapse position information, if it is not in the preset processing threshold value, no processing is performed.

[0019] The application comprises the following steps:

[0020] Step one: determining the length of the optical fiber required in the roadway according to the length of the roadway roof;

[0021] Step two: fixing the light along the direction of the roadway using a support fixing device on the roadway roof;

[0022] Step three: obtaining the position information of the fiber mutation point using the optical fiber output device;

[0023] Step four: obtaining the change information of the roadway roof by analyzing the position information of the fiber mutation point; when any parameter in the change information is not in the preset normal threshold value, the roadway collapse position is reinforced; the predicted roadway collapse position information is obtained by analyzing the change information of the roadway roof.

[0024] Compared with the related art, the application and the use method of the optical fiber for predicting the collapse of the roadway roof have the following beneficial effects:

[0025] 1. The application can monitor the stress and strain information of the roadway roof in real time through the optical fiber output device, can timely find the problems such as the displacement and falling of the surrounding rock, improves the monitoring effect on the safety of the roadway, and can accurately determine the position where the roadway roof changes by using the position information of the fiber mutation point.

[0026] 2. The application combines the change information of the roadway roof, obtains the prediction result by analyzing and processing the change information, can better evaluate the stability and safety of the roadway, and realizes the intelligent prediction of the collapse position of the roadway by using the prediction model unit and the model application unit, takes the reinforcing support measures in advance, and guarantees the safe operation of the roadway.

[0027] 3. The application can automatically adjust according to the change information through the prediction and adjustment module, judges according to the comparison result of the re-measured deformation prediction value and the re-measured change prediction value, and realizes the improvement of the accuracy and reliability of the prediction result.

[0028] In summary, the application can effectively monitor the safety state of the roadway roof, predicts the collapse position in advance, and provides reliable safety protection for the roadway engineering. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1Structure diagram of embodiment 1 of the application provided by the fiber for predicting the roof collapse of the roadway and the application and use method thereof;

[0030] Figure 2 Arrangement profile view of the fiber along the direction of the roadway of the application provided by the fiber for predicting the roof collapse of the roadway;

[0031] Figure 3 Schematic diagram of the mutation point of the fiber when the roof stone of the roadway falls of the application provided by the fiber for predicting the roof collapse of the roadway;

[0032] Figure 4 Schematic diagram of the mutation point of the fiber when the roof stone of the roadway falls of the application provided by the fiber for predicting the roof collapse of the roadway;

[0033] Figure 5 Schematic diagram of the deformation plane coordinate system of the application provided by the fiber for predicting the roof collapse of the roadway.

[0034] Marked number in the figure: 1, fiber, 2, roof of the roadway, 3, roadway, 4, mutation point of the fiber. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] The terms used in the present disclosure are merely for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The singular forms "a", "an" and "the" used in the present disclosure and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0037] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, these information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the present disclosure, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "when" or "in response to determining" that a certain condition is satisfied

[0038] Please refer to Figures 1-5The application and use method of optical fiber for predicting the roof collapse of a roadway, comprising: fixing an optical fiber 1 on the roof 2 of the roadway 3 along the direction of the roadway 3;

[0039] When the surrounding rock on the roof 2 of the roadway 3 is displaced and falls, the optical fiber 1 generates an optical fiber mutation point 4 at the falling position; the position information of the optical fiber mutation point 4 is obtained by using an optical fiber output device; the change information of the roof 2 of the roadway 3 is obtained by analyzing the position information of the optical fiber mutation point 4, and when any parameter in the change information is not in the preset normal threshold value, the falling position of the roadway 3 is reinforced; the predicted falling position information of the roadway 3 is obtained by analyzing the change information of the roof 2 of the roadway 3.

[0040] In the present application, the position information of the optical fiber mutation point 4 is obtained by using an optical fiber output device, specifically:

[0041] The stress and strain information of the roof 2 of the roadway 3 is obtained by real-time monitoring of the optical fiber 1, and the stress and strain information of the roof 2 of the roadway 3 is sent to a roadway monitoring center and stored by the optical fiber output device; the stress and strain information of the roof 2 of the roadway 3 is received by the roadway monitoring center and is analyzed, processed and interpreted, the influence of temperature is eliminated by using the linear relationship between the frequency shift amount of the Brillouin backscattering light and the strain and temperature, so as to obtain the position information of the optical fiber mutation point 4; wherein the stress and strain information includes the frequency shift amount of the Brillouin backscattering light, the strain distribution and the temperature distribution of the roof 2 of the roadway 3 in the radial direction;

[0042] Wherein, the specific relationship in the above is that the linear relationship between the frequency shift amount of the Brillouin backscattering light and the strain and temperature is represented as The relationship between the frequency shift of the temperature compensation optical fiber and the temperature is The relationship between the frequency shift and the strain after eliminating the influence of temperature is Gx(ε,0)=Gx(ε,T)-Gx(0,T); and finally the position information of the optical fiber mutation point (4) is obtained Wherein, Gx(ε,T) represents the frequency shift amount of the Brillouin backscattering light under the action of strain and temperature, α and β represent the proportional constant corresponding to strain and temperature, δ represents the temperature compensation constant, and ε and T represent the strain distribution and the temperature distribution of the roof 2 of the roadway 3 in the radial direction, respectively.

[0043] In the present application, the change information of the roof 2 of the roadway 3 is obtained by analyzing the position information of the optical fiber mutation point 4, and the specific analysis is as follows:

[0044] The position of the outer edge of the surrounding rock on the roof 2 of the roadway 3 is taken as the starting point, the frequency shift amount of the Brillouin backscattering light in the stress and strain information obtained from the optical fiber output device, and the strain distribution ε of the roof 2 of the roadway 3 in the radial direction are used to perform operation by using the variance calculation formula of continuous random variables The deformation value of the roadway roof 2 in the radial direction is obtained; wherein, Sj represents the deformation value at the jth edge of the surrounding rock of the roadway roof 2, and dz represents a small length element changing along the radial direction of the surrounding rock of the roadway roof 2;

[0045] The deformation value of the roadway roof 2 in the radial direction at several preset time zones before the current time is obtained, a deformation plane coordinate system of each preset time zone is constructed, the deformation value in the preset time zone is substituted into the deformation plane coordinate system according to the collection time, the position of the deformation value in the deformation plane coordinate system is marked as a deformation point, two deformation points spaced by one deformation point are connected to obtain an auxiliary line, a triangle is formed by the two deformation lines and the auxiliary line, and the area of the triangle is calculated; the area of the triangle above the auxiliary line is marked as an ascending triangle value, and the area of the triangle below the auxiliary line is marked as a descending triangle value; the sum of all ascending triangle values is taken to obtain an ascending average value B1, and the sum of all descending triangle values is taken to obtain a descending average value B2; the ascending average value and the descending average value are calculated, and the formula B=B1*b1+B2*b2 is used to obtain the change value of the roadway roof 2 in the radial direction; wherein, b1 and b2 represent proportional constants corresponding to the ascending average value and the descending average value, respectively; the deformation value and the change value of the roadway roof 2 in the radial direction are marked as change information;

[0046] Vibration information of the outer edge of the surrounding rock on the roadway roof 2 is obtained, the vibration information including the vibration frequency of the outer edge of the surrounding rock, Fourier analysis is performed on the vibration information, and the vibration information is converted into frequency values by using discrete Fourier transform, which is represented by the formula X[k]=∑[n=0toN-1](x[n]*e (-h2πk*n / N) ); wherein, X[k] represents a complex value of the kth frequency component in the frequency domain and is marked as a frequency value, (k=0, 1, 2,..., N-1), x[n] represents a signal value of the nth sampling point in the time domain, N represents the length of the signal, h represents an imaginary unit, and 2π represents the angle of a period; a preset threshold value of the frequency value is set and compared, if the frequency value is in the preset threshold value, the roadway roof 2 is normal, and if the frequency value is not in the preset threshold value, there is gangue falling on the roadway roof 2; when the gangue falls, the falling speed of the gangue is obtained, the falling time of the gangue is marked as an initial falling time, the time difference between the current time and the initial falling time is calculated to obtain a falling time difference, the falling time difference is divided into a plurality of falling time zones according to equal time, the falling acceleration of the falling time zone is calculated, and the acceleration of the gangue is obtained by calculating the falling acceleration of the falling time zone.

[0047] The roadway monitoring center in the application further comprises a prediction model unit and a model application unit; the prediction model unit uses a MATLAB neural network tool to select deformation values and change values of a specified number of preset time zones before a current time and corresponding collection time and acceleration of the gangue according to an ANFIS function, and accordingly generates a deformation model and a change model based on ANFIS respectively;

[0048] The model application unit inputs the prediction time zone into the deformation model based on ANFIS to obtain a deformation prediction value Sn+m of the prediction time zone; and inputs the prediction time zone into the change model based on ANFIS to obtain a change prediction value Bn+m of the prediction time zone.

[0049] wherein preset time zones are marked as t0, t1, t2, t3...tn, a prediction time length is obtained by using a formula t1-t0=t2-t1=...=tn-tn-1=▽t, t0 represents an initial preset time zone among all preset time zones before a current time, tn represents a preset time zone at the current time, m represents a number of preset time zones of the deformation value and the change value selected on the radial direction of the predicted roadway roof 2, and m is a positive number, and m▽t represents preset time zones accumulated by m and marked as a prediction time zone;

[0050] The normal threshold values of the deformation value and the change value are set as Sz and Bz in combination with a specific engineering object, the deformation prediction value and the change prediction value are compared with the corresponding normal threshold values, if Sn+m≤Sz and Bn+m≤Bz, no treatment is performed, if any one of Sn+m>Sz or Bn+m>Bz, the position information of the fiber abrupt change point 4 at this moment is marked as predicted roadway 3 collapse position information and the position is subjected to reinforced support treatment.

[0051] wherein the reinforced support treatment includes but is not limited to:

[0052] reinforcing the roof structure by increasing steel bars, thickening concrete, etc.; or enhancing the support structure by installing steel beams, steel frames, etc. on the roadway roof 2; or increasing the strength of the stratum by pumping special materials into the stratum by using a pump, the special materials being cement slurry, polymer or other additives.

[0053] In a specific example, for example, the preset time zone is one hour, the ANFIS function selects deformation values and change values of thirty preset time zones before a current time and corresponding collection time, and accordingly generates a prediction model; if the prediction time zone is five hours, m=5 is input into The current time, i.e. five hours after the current time, is input into the prediction model to obtain the deformation prediction value and the change prediction value after five hours, and if the change prediction value and the change prediction value after five hours are not within the corresponding normal threshold, the position information of the fiber mutation point 4 at this moment is marked as the predicted roadway 3 collapse position information and the position is subjected to reinforced support treatment.

[0054] The application comprises the following steps:

[0055] Step one: determining the length of the optical fiber 1 required in the roadway 3 according to the length of the roadway roof 2;

[0056] Step two: fixing the optical fiber 1 on the roadway roof 2 along the direction of the roadway 3 using a support fixing device;

[0057] Step three: obtaining the position information of the fiber mutation point 4 using the optical fiber output device;

[0058] Step four: obtaining the change information of the roadway roof 2 by analyzing the position information of the fiber mutation point 4; when any parameter in the change information is not within the preset normal threshold, the roadway 3 collapse position is subjected to reinforced support; the predicted roadway 3 collapse position information is obtained by analyzing the change information of the roadway roof 2.

[0059] Embodiment 2

[0060] Please refer to Figure 3 As shown in the application, based on the application of the optical fiber provided in embodiment 1 for predicting the collapse of the roadway roof, the application of the optical fiber provided in embodiment 2 for predicting the collapse of the roadway roof is proposed. Embodiment 2 is only a preferred mode of embodiment 1, and the implementation of embodiment 2 will not affect the implementation of embodiment 1.

[0061] Specifically, the application of the optical fiber provided in embodiment 2 for predicting the collapse of the roadway roof is different in that:

[0062] In the application, the roadway monitoring center further comprises a prediction adjustment module; the prediction adjustment module is used to adjust the specified number of preset time zones before the current time selected by the ANFIS function to perform verification analysis, specifically:

[0063] When any parameter in the change information is not within the preset normal threshold, the specified number of the preset time zones before the current time selected by the ANFIS function is adjusted, the specified number is weighted and adjusted, the specified number is calculated by adding a preset number to obtain the adjusted specified number, and the above process is repeated until the number of the adjusted specified number reaches the preset number threshold.

[0064] The deformation value and the change value of the specified number of preset time zones before the current time are selected, and the deformation model and the change model based on ANFIS are adjusted by using the selected deformation value and change value and the corresponding collection time to generate the re-measured deformation prediction value S of the predicted time zone i n+m and the re-measured change prediction value B i n+m, i represents the number of times of weighted adjustment of the specified number; all re-measured deformation prediction values S i n+m and the re-measured change prediction value B i n+m are compared with the normal threshold values of the deformation value and the change value, respectively, and the number of Sin+m≤Sz and B i n+m≤Bz is marked as the non-treatment number, and the number of any one of Sin+m>Sz or B i n+m>Bz is marked as the treatment number; the product of the non-treatment number and the treatment number and the corresponding weight is summed to obtain a processing value; the processing value is compared with a preset processing threshold value, if it is within the preset processing threshold value, the position information of the optical fiber abrupt change point 4 is marked as the predicted roadway 3 collapse position information, if it is not within the preset processing threshold value, no treatment is performed.

[0065] In a specific example, when any one parameter in the change information is not within the preset normal threshold value, the specified number of preset time zones before the current time is selected by adjusting the ANFIS function, for example, the specified number of preset time zones before the current time is set to twenty-four, that is, the deformation value and the change value of the twenty-four hours before the current time are selected and the corresponding collection time is selected; the specified number is weighted and adjusted, that is, the specified number and the preset number are accumulated, for example, the preset number is three and the preset number threshold value is ten, then the first adjusted specified number is twenty-seven, the second is thirty, and so on, until the tenth adjusted specified number is fifty-four, that is, the re-measured deformation prediction value and the re-measured change prediction value after each adjustment are obtained; the re-measured deformation prediction value and the re-measured change prediction value are compared with the corresponding normal threshold value to obtain the corresponding number of the re-prediction result; the product of the non-treatment number and the treatment number and the corresponding weight is summed to obtain a processing value; the prediction result is re-judged according to the processing value to improve the accuracy of the prediction result.

[0066] By repeatedly adjusting the specified number of preset time zones before the current time, the prediction model can better adapt to the actual situation, so that accidental errors or abnormal situations can be excluded, the credibility of the prediction result can be enhanced, and the prediction accuracy of the roadway 3 collapse position can be further improved.

[0067] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the application be construed as including any patent, any patent applications, and any patent publications to the extent that such patent, patent applications, and patent publications are consistent with the present disclosure. It is intended that the specification and examples be considered exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0068] It is to be understood that the application is not limited to the precise construction herein disclosed and shown in the drawings, and that various modifications and changes can be effected therein by those skilled in the art without departing from the scope of the application. The scope of the application is to be limited only by the appended claims.

Claims

1. An application of optical fiber to predict roof fall in a mine roadway, characterized in that, The utility model relates to a kind of mine roof displacement monitoring system based on optical fiber, including: Fix optical fiber (1) on roadway roof (2) along the direction of roadway (3) trend; When the displacement of surrounding rock on roadway roof (2) occurs and gangue falls, optical fiber (1) generates optical fiber mutation point (4) at the falling position;The position information of optical fiber mutation point (4) is obtained by using optical fiber output device;By analyzing the position information of optical fiber mutation point (4), the change information of roadway roof (2) is obtained, when any parameter in the change information is not in the preset normal threshold, the falling position of roadway (3) is strengthened;The falling position information of roadway (3) is obtained by analyzing the change information of roadway roof (2); The position information of optical fiber mutation point (4) is obtained by using optical fiber output device, specifically: The stress and strain information of roadway roof (2) is monitored by optical fiber (1) in real time, and the stress and strain information of roadway roof (2) is sent to the roadway monitoring center and stored by optical fiber output device;The stress and strain information of roadway roof (2) is received by the roadway monitoring center and analyzed, processed and interpreted, the linear relationship between the frequency shift amount of Brillouin backscattering light and strain and temperature is used to eliminate the influence of temperature, so as to obtain the position information of optical fiber mutation point (4);Wherein, the stress and strain information includes the frequency shift amount of Brillouin backscattering light, the strain distribution and temperature distribution in the radial direction of roadway roof (2); The change information of roadway roof (2) is obtained by analyzing the position information of optical fiber mutation point (4), and the specific analysis is as follows: The position of the outer edge of the surrounding rock on the roadway roof (2) is taken as the starting point, the frequency shift amount of Brillouin backscattering light in the stress and strain information obtained from the optical fiber output device, and the strain distribution in the radial direction of roadway roof (2) are used to calculate the deformation value in the radial direction of roadway roof (2) by using the variance calculation formula of continuous random variable; The deformation value in the radial direction of roadway roof (2) in several preset time zones before the current time is obtained, a deformation plane coordinate system of each preset time zone is constructed, the deformation value in the preset time zone is substituted into the deformation plane coordinate system according to the collection time, the position of the deformation value in the deformation plane coordinate system is marked as a deformation point, two deformation points with an interval are connected to obtain an auxiliary line, a triangle is formed by two deformation lines and the auxiliary line, and the area of the triangle is calculated;The area of the triangle above the auxiliary line is marked as an ascending triangle value, and the area of the triangle below the auxiliary line is marked as a descending triangle value;The sum of all ascending triangle values is taken to obtain an ascending average value, and the sum of all descending triangle values is taken to obtain a descending average value;The ascending average value and the descending average value are calculated to obtain the change value in the radial direction of the preset time zone of roadway roof (2);The deformation value and the change value in the radial direction of roadway roof (2) are marked as change information. The vibration information of the outer edge of the surrounding rock on the roadway roof (2) is acquired, and the vibration information includes the vibration frequency of the outer edge of the surrounding rock. The vibration information is subjected to Fourier analysis, and the vibration information is converted into frequency values by using discrete Fourier transform. A preset threshold of the frequency values is set and compared. If the frequency values are in the preset threshold, the roadway roof (2) is normal. If the frequency values are not in the preset threshold, the roadway roof (2) has gangue falling. When the gangue falls, the falling speed of the gangue is acquired. The falling moment of the gangue is marked as an initial falling moment. The falling time difference is calculated by comparing the current moment with the initial falling moment. The falling time difference is divided into a plurality of falling time zones according to equal time. The falling acceleration of the falling time zone is calculated. The acceleration of the gangue is calculated by calculating the falling accelerations of the plurality of falling time zones.

2. The use of an optical fiber to predict roof collapse in a mine tunnel according to claim 1, wherein, The roadway monitoring center further comprises a prediction model unit and a model application unit. The prediction model unit uses the MATLAB neural network tool to select the deformation values and change values of the specified number of preset time zones before the current moment, the corresponding collection moments and the acceleration of the gangue by using the ANFIS function, and generates the deformation model and the change model based on ANFIS, respectively. The model application unit inputs the predicted time zone into the ANFIS-based deformation model , to obtain a deformation prediction value of the predicted time zone; inputs the predicted time zone into the ANFIS-based change model, to obtain a change prediction value of the predicted time zone; sets normal threshold values of the deformation value and the change value according to the specific engineering object, compares the deformation prediction value and the change prediction value with the corresponding normal threshold values, if both are within the corresponding normal threshold values, no treatment is performed, if any one is not within the corresponding normal threshold value, the position information of the fiber catastrophe point (4) at this moment is marked as the predicted roadway (3) collapse position information, and the position is subjected to reinforced support treatment.

3. The use of an optical fiber to predict roof collapse in a mine entry according to claim 2, wherein, The roadway monitoring center further comprises a prediction re-adjustment module. The prediction re-adjustment module is used to adjust the specified number of preset time zones before the current moment by using the ANFIS function, so as to perform verification analysis. Specifically: When any one parameter in the change information is not in the preset normal threshold, the specified number of preset time zones before the current moment is adjusted by using the ANFIS function. The specified number is adjusted by weighting. The adjusted specified number is calculated by adding a preset number. This is repeated until the number of the adjusted specified number reaches the preset number threshold. The deformation values and change values of the adjusted specified number of preset time zones before the current moment are used to adjust the deformation model and the change model based on ANFIS by using the corresponding collection moments. The prediction time zone is input into the adjusted deformation model and the change model based on ANFIS, so as to generate the re-measured deformation prediction value and the re-measured change prediction value of the prediction time zone. All the re-measured deformation prediction values and the re-measured change prediction values are compared with the normal threshold of the deformation values and the change values, respectively. The number of values that are in the corresponding normal threshold is marked as the non-required number. The number of values that are not in the corresponding normal threshold is marked as the required number. The product of the non-required number and the required number and the corresponding weight is summed to obtain a processing value. The processing value is compared with the preset processing threshold. If the processing value is in the preset processing threshold, the position information of the optical fiber abrupt change point (4) is marked as the prediction roadway (3) collapse position information. If the processing value is not in the preset processing threshold, no processing is performed.

4. A method of using an optical fiber to predict a roof fall in a mine tunnel, comprising: The application of the optical fiber prediction roadway collapse according to any one of claims 1 to 3 comprises the following steps: Step one: The length of the optical fiber (1) required in the roadway (3) is determined according to the length of the roadway roof (2). Step two: the optical fiber (1) is fixed on the roadway roof (2) along the direction of the roadway (3) by using the support fixing device; Step three: the position information of the optical fiber mutation point (4) is obtained by using the optical fiber output device; Step four: the change information of the roadway roof (2) is obtained by analyzing the position information of the optical fiber mutation point (4); when any parameter in the change information is not in the preset normal threshold value, the support of the roadway (3) collapse position is strengthened; the predicted roadway (3) collapse position information is obtained by analyzing the change information of the roadway roof (2).

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