CN115839772A - Tunnel stress infrared monitoring method and device for solving wind flow influence - Google Patents
Tunnel stress infrared monitoring method and device for solving wind flow influence Download PDFInfo
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Abstract
The invention is suitable for the fields of mine safety and rock mechanics, and provides a roadway stress infrared monitoring method and a roadway stress infrared monitoring device for solving the influence of wind current, wherein the method comprises the following steps: the method comprises the steps of calculating the heat exchange quantity of roadway surrounding rocks and wind current in a mine shaft, calculating the temperature influence of the wind current on the roadway surrounding rocks through a relational expression of the heat exchange quantity and the temperature, removing the roadway surrounding rocks, only leaving the temperature difference of the roadway surrounding rocks caused by different stress distributions, removing the temperature field of the roadway surrounding rocks influenced by the wind current, combining the coupling thermodynamics of the temperature field change caused by rock deformation, and obtaining the relational expression between the temperature field change and the stress field by utilizing the elastic heat effect in the deformation process of the roadway surrounding rocks. The method is based on the infrared thermal imaging technology, and can predict the occurrence of disasters by measuring the stress of surrounding rocks of the roadway without the influence of wind current and judging the position where the rock burst is likely to occur according to the displayed stress.
Description
Technical Field
The invention belongs to the technical field of mine safety and rock mechanics, and particularly relates to a roadway stress infrared monitoring method and device for solving the influence of wind current.
Background
China is a large mining country, has a plurality of important mining projects, and with the development of the mining industry of China, more and more mine rock burst disasters are frequently found, and the main reason for the problems is that the original stress structure is changed because hard and brittle rock masses are excavated and unloaded in the mining process, so that the original stable and safe stress structure is changed, and dynamic unstable geological disasters of the phenomena of burst loosening, stripping, ejection and even throwing are generated, thereby endangering the benefits and safety of workers and people. Therefore, the effective prediction and identification of the mine catastrophe process becomes the main direction of mine catastrophe early warning and disaster prevention and reduction. It is therefore of great interest to develop a stress detection system.
At present, the research on the prevention technology of the rock burst risk mainly lies in the acoustic field. Specifically, in the acoustic field, three directions are divided: the method comprises a microseismic technology, an acoustic emission technology and an audio frequency detection technology, and the three methods can predict the rock burst risk to a certain extent. However, under the problem of influence of environmental factors in an actual roadway, false alarm often occurs, the current system does not reach the level capable of intelligent judgment, the final results presented by the three technologies are quite non-intuitive, a professional is required to analyze to determine the position where rock burst is likely to occur, and certain artificial subjective factor influence exists.
Because the inoculation of rock burst is the process that the rock mass is stressed to absorb energy in the excavation disturbance environment, the rock mass can release corresponding infrared spectrum in different stages due to the absorbed energy, and the existing research finds that: the infrared radiation temperature of the rock changes along with the stress of the rock, which is mainly because the strain energy of rock deformation at the position of roadway surrounding rock with high stress is converted into radiation energy, and the infrared temperature rise is directly caused. Therefore, a more stable and visual infrared thermal imaging technology is introduced to detect the temperature field of the surrounding rock of the roadway so as to prevent rock burst. An infrared detection system for detecting the position where the rock burst may occur according to the magnitude of the infrared radiation temperature also appears in the market, but the current infrared detection system still has shortcomings, one of which is as follows: the infrared radiation temperature of the surrounding rock of the roadway is easily influenced by wind current in the roadway, and no method for removing the influence of the wind current on the infrared radiation temperature of the surrounding rock of the roadway exists; the second step is as follows: at present, no equipment capable of directly observing the stress of surrounding rock of a roadway exists.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide an infrared monitoring method and device for roadway stress to solve the wind flow effect, and to solve the above technical problems.
The invention adopts the following technical scheme:
on one hand, the roadway stress infrared monitoring method for solving the wind flow influence comprises the following steps:
s1, acquiring thermophysical coefficients of surrounding rock of a roadway and roadway size parameters;
s2, calculating the radius of the heat regulation zone, and calculating to obtain the final heat flux density of the wall surface of the surrounding rock of the roadway by combining the original rock temperature and the temperature measurement value of a temperature measurement point in the surrounding rock of the roadway, so as to obtain the heat of heat exchange between the wind current and the surrounding rock of the roadway;
s3, calculating a temperature change value of the wind current to a roadway surrounding rock temperature field according to the corresponding relation between the heat and the temperature;
s4, measuring the temperature value of each pixel of an infrared temperature field of the wall surface of the surrounding rock of the roadway, which is influenced by the wind flow and the stress, and combining the temperature change value to finally obtain an infrared temperature field image of the wall surface of the surrounding rock of the roadway, which is not influenced by the wind flow and is only influenced by the stress;
and S5, obtaining the average temperature value of the test block without the influence of the wind current on the stress, calculating the difference value between each pixel of the infrared temperature field image on the wall surface of the surrounding rock of the roadway and the average temperature value of the test block, obtaining the stress tensor change of each pixel point through calculation, and finally converting the stress tensor change into the stress value of each pixel point.
On the other hand, the roadway stress infrared monitoring device for solving the wind current influence comprises a thermal infrared imager, a laser ranging device and an ultrasonic wind speed and wind temperature measuring instrument, wherein an industrial control board is further arranged in the roadway stress infrared monitoring device and used for executing the roadway stress infrared monitoring method.
The beneficial effects of the invention are: according to the method, the wind speed and the wind temperature in the tunnel are measured by using the ultrasonic wind speed and wind temperature measuring instrument, then the wind speed is taken as a variable, the difference value of the temperatures of the surrounding rock and the wind flow in the tunnel is combined, and the fitted convective heat transfer coefficient calculation formula is used, so that the problem that the infrared temperature field of the surrounding rock of the tunnel is influenced by the wind flow in the infrared thermal imaging method is solved. The method explores the stress distribution and interaction of the surrounding rock of the roadway by utilizing thermal infrared radiation research, and has good consistency of the evolution trend and the amplitude of the temperature and the stress based on the thermodynamic theory, the heat transfer theory and the observation result in a laboratory, thereby having good application prospect.
Drawings
Fig. 1 is a flowchart of a roadway stress infrared monitoring method for solving wind flow influence according to an embodiment of the present invention;
FIG. 2 is a schematic view of a radius of a thermal control ring provided in an embodiment of the present invention;
fig. 3 is a perspective view of a roadway stress infrared monitoring device for solving the wind flow influence according to an embodiment of the present invention;
fig. 4 is a rear view of a roadway stress infrared monitoring device for solving the wind flow influence according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In order to explain the technical means of the present invention, the following description will be given by way of specific examples.
The first embodiment is as follows:
as shown in fig. 1, the method for monitoring roadway stress by infrared to solve the wind flow influence provided by this embodiment includes the following steps:
s1, acquiring thermophysical coefficients and roadway size parameters of roadway surrounding rock.
Firstly, obtaining thermophysical coefficients of the surrounding rock of the roadway to be mined in a laboratory, wherein the thermophysical coefficients comprise a heat conductivity coefficient lambda, specific heat C, density rho, heat capacity Cp and a temperature conductivity coefficient alpha, the parameters are constants, and the parameters can be directly input after being measured.
And then measuring the size parameters of the roadway, including the hydraulic radius r0 of the roadway, the area S of the measured wall surface and the like, in addition, the perimeter of the roadway, the area of the section of the roadway and the like, by using a laser ranging device, and outputting the size parameters.
And S2, calculating the radius of the heat regulating zone, and calculating to obtain the final heat flux density of the wall surface of the surrounding rock of the roadway by combining the original rock temperature and the temperature measurement value of a temperature measurement point in the surrounding rock of the roadway, thereby obtaining the heat of heat exchange between the wind current and the surrounding rock of the roadway.
The radius of the heat regulation zone is calculated through a heat regulation zone radius calculation formula, and the original rock temperature ty and the temperature Y change at a point depth re in the roadway surrounding rock mass are measured by using the drill holes before the radius of the heat regulation zone is calculated. Specifically, after drilling, a temperature measuring sensor is placed in the tunnel, the temperature measuring sensor is used for measuring the original rock temperature ty at a position 1.5m away from the wall surface of the surrounding rock of the tunnel, and when the temperature Y of the point of the internal depth re of the rock is measured, the depth of the drilled hole cannot exceed the radius rt of a heating coil.
In the embodiment, a drilling mode is adopted, and the temperature of the original rock and the temperature change of the surrounding rock are measured through the temperature measuring sensor, so that the heat flow density value of the wall surface of the surrounding rock of the roadway can be subsequently calculated. The depth of the drilled hole, i.e. the temperature measuring point, should be able to fully reflect the change of the rock temperature. In the embodiment, the air drill is used for drilling, circulating water is used as drilling fluid in the air drill in the drilling process, heat generated by friction of the drilling tool can be cooled, the rock temperature is cooled to a certain extent, and the original rock temperature is measured in the drilling process. The depth of the drilled hole is not too shallow, if the drilled hole is too close to the wall surface, the change of the rock temperature is greatly influenced by wind flow, the interference is too strong, but the drilled hole cannot be too deep to exceed the outer radius of the roadway heat regulation circle, and the change of the temperature cannot be measured if the temperature measurement point exceeds the outer radius of the roadway heat regulation circle. The selection of the temperature measuring instrument has a great influence on the accuracy of the measured temperature, the higher the accuracy is, the closer the measured temperature is to the true value, the smaller the data error is, and the smaller the value error of the estimated heat flow density is. The temperature sensor is used for measuring the temperature of the deep part of the rock, so that the influence of the change of the wind flow state in the tunnel on the temperature measurement precision can be avoided.
The calculation formula of the radius of the heat regulation ring is rt = r 0 +(r 0 2 +12αt) 1/2 Wherein the hydraulic radius of the tunnel is r0, the temperature coefficient is alpha, and the time required by drilling and temperature measurement is t. The initial temperature of the surrounding rock is kept at t0, and t0= ty at the outer boundary of the heat regulating ring. The schematic diagram of the radius of the heat regulating ring is shown in fig. 2. And inputting the original rock temperature ty and the temperature Y of a point of the internal depth re of the rock as parameters after measurement.
The heat flux density of the surrounding rock of the roadway may also be a positive value or a negative value due to the continuous heat exchange with the wind current. When the heat flux density is a negative value, the surrounding rock transfers heat to the wind flow, and the wall surface temperature of the surrounding rock is higher than the temperature of the wind flow; when the value is positive, the surrounding rock absorbs the heat in the wind flow, and the temperature of the wind flow is higher than the temperature of the wall surface of the surrounding rock. And (3) obtaining the heat flow density qe of a temperature measuring point in the surrounding rock body of the roadway according to the temperature measurement value Y of the depth re inside the surrounding rock:
the heat flux density q of the final roadway surrounding rock wall surface is obtained through calculation according to the formula:
and multiplying the calculated heat flow density Q by the measured wall surface area S to obtain the heat quantity Q1 of the heat exchange between the wind flow and the surrounding rock of the roadway.
And S3, calculating a temperature change value of the wind current to the roadway surrounding rock temperature field according to the corresponding relation between the heat and the temperature.
The corresponding relation between the heat and the temperature is Q1= a (t 2-t 1) S, t1 is a temperature value which is only influenced by stress under the condition of no wind, t2 is a temperature value which is influenced by the stress under the condition of wind, a is a convection heat transfer coefficient and is related to wind speed and wind temperature, and S is the measured wall surface area and is measured by a laser ranging device. And (3) obtaining the temperature influence of the wind flow on the wall surface of the surrounding rock according to the corresponding relation between the heat and the temperature, wherein (t 2-t 1) is the temperature change value of the wind flow on the temperature field of the roadway surrounding rock.
The calculation method of the convective heat transfer coefficient a is as follows: and fitting a convection heat transfer coefficient calculation formula by using the wind speed and wind temperature numerical value measured by the ultrasonic wind speed and wind temperature measuring instrument and taking the wind speed of the tunnel as a variable according to the difference value of the wind flow temperature in the surrounding rock and the tunnel, and finally calculating the convection heat transfer coefficient a. Because Q1, a and S are calculated, the temperature variation (t 2-t 1) of the wall surface of the surrounding rock of the roadway without the influence of wind can be calculated according to the corresponding relation between heat and temperature.
And S4, measuring the temperature value of each pixel of the infrared temperature field of the wall surface of the surrounding rock of the roadway, which is influenced by the wind flow and the stress, and combining the temperature change value to finally obtain the infrared temperature field image of the wall surface of the surrounding rock of the roadway, which is not influenced by the wind flow and the stress.
Measuring the temperature values of all pixels of an infrared temperature field of the wall surface of the surrounding rock of the roadway, which is affected by wind current and stress, by using an infrared thermal imager, assuming that n pixels exist, the temperature values are [ T1, T2 and T3.. Tn ], subtracting the temperature change value (T2-T1) from the temperature values of all pixels to obtain an infrared temperature field image of the wall surface of the surrounding rock of the roadway, which is affected only by the stress without wind current, wherein the temperature of each pixel in the image is [ T01, T02 and T03.. T0n ], and finally displaying the infrared temperature field image which is affected only by the stress without wind current.
And S5, obtaining the average temperature value of the test block without the influence of the wind current on the stress, calculating the difference value between each pixel of the infrared temperature field image on the wall surface of the surrounding rock of the roadway and the average temperature value of the test block, obtaining the stress tensor change of each pixel point through calculation, and finally converting the stress tensor change into the stress value of each pixel point.
The temperature field change accompanying the material deformation process, the relation between the material elastic deformation and the temperature field change is an elastic thermal effect, the elastic thermal effect can be used for explaining the change of the roadway surrounding rock, namely the change of the temperature field in the stress change process, the temperature field of the roadway surrounding rock wall surface without wind influence is obtained through the algorithm for influencing the roadway surrounding rock temperature by the wind flow, and this shows that the treated roadway surrounding rock temperature field is only influenced by the stress field, and the state of the roadway surrounding rock stress field at the moment is reversely deduced through the temperature field.
The relation between the change of the rock temperature and the change of the stress tensor is as follows:
T0i-T00＝-T00×a/(ρ*Cρ)×Δδkk
wherein T0i is a pixel temperature value of an infrared temperature field image of a wall surface of a surrounding rock of a roadway, which is only affected by stress without wind current, i.e. each pixel temperature value [ T01, T02, T03.. T0n ] of the infrared temperature field image of the surrounding rock, which is only affected by stress under the windless condition, T00 is an average temperature value of a test block, which is not affected by stress without wind current, a is a convective heat transfer coefficient, ρ is the density of a rock body, cp is the thermal capacity of the rock body, and Δ δ kk is the change of a stress tensor.
Because T0i, a, rho and Crho are known, a small test block is placed at a windless position in a mine hole in advance, the stress of the test block can be ignored compared with the stress of surrounding rocks of the roadway and is considered as 0, so that the average temperature value T00 of the test block which is not influenced by the stress under the windless condition can be measured by an infrared thermal imager, finally, the change delta kk of the stress tensor can be calculated according to a formula, the change delta kk of the measured data stress tensor is converted into a stress value, and the stress value of each part of the surrounding rocks of the roadway can be visually seen on a screen.
In the experiment that the infrared thermal imager is used for carrying out uniaxial loading on the rock test blocks with different shapes, the following results are found: (1) In the process of uniaxial loading, the infrared radiation temperature of the ore changes along with stress, wherein the ore is calm or slightly falls at the initial stage of loading, then slowly rises, and quickly rises before cracking; 2) When the ore enters the damage process from the stress peak stage, the thermal image shows that the low-temperature zone is expanded, and the low-temperature strip is the position of the subsequent main fracture; (3) With the increase of the stress, the infrared radiation spectrum of the rock is obviously increased in radiation intensity under the condition of keeping the shape of the rock basically unchanged, and the infrared radiation intensity of the rock before the fracture reaches the highest value. Therefore, the temperature field of the surrounding rock of the roadway can be detected by using a stable and visual infrared thermal imaging technology, so that the rockburst can be prevented.
However, when a wind current with a lower temperature than that of the surrounding rock flows through the roadway after the roadway is cut in the rock, the wall of the roadway radiates heat to the wind current in a convection heat radiation manner due to the temperature difference, and the surrounding rock mass generates a heat flow to the cooled roadway wall in a heat conduction manner, and at the same time, the surrounding rock mass in the deep part of the periphery is correspondingly cooled to form a cooling zone. The temperature of the wind flow in the tunnel is increased after obtaining heat, and the temperature distribution of the surrounding rock mass and the wind temperature of the tunnel change along with the time, which is an unstable heat transfer process. The process comprises heat conduction inside the surrounding rock body and convection heat exchange between the surrounding rock and wind flow, and is a combined unstable heat transfer process. Therefore, in order to better detect the temperature field of the surrounding rock of the roadway by using the infrared thermal imaging technology, the influence of the wind flow on the temperature field of the surrounding rock of the roadway must be eliminated.
The embodiment provides a method for solving the problem, the heat exchange quantity of the surrounding rocks of the roadway and the wind current in the mine is calculated, the temperature influence of the wind current on the surrounding rocks of the roadway is calculated through a relational expression of the heat exchange quantity and the temperature, only the temperature difference of the surrounding rocks of the roadway caused by different stress distributions is left, then the temperature field of the surrounding rocks of the roadway influenced by the wind current is removed through a temperature algorithm of the surrounding rocks of the roadway influenced by the wind current, and an integral algorithm is formed by combining the coupling thermodynamics of the temperature field change caused by the rock deformation and the relational expression between the temperature field change and the stress field obtained by using the elastic thermal effect in the deformation process of the surrounding rocks of the roadway, so that the stress values of different positions of the surrounding rocks of the roadway are obtained.
Example two:
the stress value is the most intuitive way for observing whether rock burst occurs in the surrounding rock of the roadway, and in the embodiment, on the basis of the method in the first embodiment, a device capable of realizing the method is designed, as shown in fig. 3 and 4, the device comprises a thermal infrared imager 1, a laser distance measuring device 2, an ultrasonic wind speed and temperature measuring instrument 3 and the like, for example, a display screen 4, an industrial control board is arranged in the device, and the industrial control board can execute the method in the first embodiment. The device can measure the wind temperature and the wind speed of the real-time wind current, the temperature of surrounding rocks of the roadway, the size of the roadway and other data on site, judge the position where rock burst is likely to occur according to the displayed stress, and predict the occurrence of disasters.
In the structure of the device, the thermal infrared imager is used for obtaining temperature distribution data of the surface of the surrounding rock of the roadway, and the thermal infrared imager works on the principle that an infrared detector and an optical imaging objective lens are used for receiving an infrared radiation energy distribution pattern of a detected target and reflecting the infrared radiation energy distribution pattern on a photosensitive element of the infrared detector, so that an infrared thermograph is obtained. In the embodiment, the place where the temperature needs to be measured is visually displayed on the display screen, the temperature value of each pixel can be read from the image, and then the measured temperature data is input into a chip of the industrial control board for calculation.
The laser ranging device is used for measuring roadway size parameters such as roadway perimeter, roadway section area, roadway hydraulic radius and measured wall surface area. And after the measurement is finished, receiving the detected size data in real time in the industrial control board and calculating.
The ultrasonic wind speed and wind temperature measuring instrument consists of two sensors, including an ultrasonic wind speed sensor and a temperature sensor. The inside of the measuring instrument is provided with a temperature sensor, so that the wind flow temperature data can be detected in real time. The ultrasonic wind speed and wind temperature measuring instrument can simultaneously output wind speed and wind temperature data, and the industrial control board receives and calculates the detected data in real time.
The device is matched with a drilling temperature measurer for use, the drilling temperature measurer mainly comprises a thermocouple, a platinum resistor and a digital temperature sensor, after the air drill is used for drilling, the temperature of one point in original rock temperature and surrounding rock bodies of a roadway is measured in the drilling process, measured data are displayed on a display screen of the temperature measurer, and the data are input into an industrial control panel for calculation.
The industrial control panel outputs the stress value of the surrounding rock without wind influence after the input data are subjected to wind current influence tunnel surrounding rock temperature calculation and tunnel surrounding rock temperature field calculation stress difference calculation, rock burst risk analysis is carried out, comprehensive analysis is carried out according to the stress distribution condition of surrounding rock masses, whether the rock burst risk reaches a threshold value is calculated, and an evaluation result is given.
A specific practical operation flow of the device is as follows:
(1) Opening the rock roadway stress infrared monitoring device and entering a data acquisition mode;
(2) Inputting rock parameters (heat conductivity coefficient, specific heat capacity, density and heat capacity) known in advance on a display screen;
(3) Clicking an icon of the laser ranging module, aligning the front side of a laser sensor of the device to the size of an object to be measured, and standing the laser sensor for a period of time (about 15 seconds): measuring the perimeter of the tunnel, the area of the section of the tunnel, the hydraulic radius of the tunnel and the dimension parameters of the tunnel of the measured wall surface area, calculating the radius of the heat regulation circle, automatically inputting, and displaying the radius of the heat regulation circle on a display screen;
(4) According to the size of the heat regulation circle, drilling by using a pneumatic drill, installing a temperature measurer in the drill hole, standing for two minutes, measuring the temperature of a point in the original rock and the surrounding rock of the roadway, which is smaller than the radius of the heat regulation circle, displaying the measured data on a display screen of the temperature measurer, and manually inputting the data on the display screen of the device;
(5) Clicking an icon of the ultrasonic wind speed and wind temperature measuring module, holding the ultrasonic wind speed and wind temperature measuring device by hand, standing for 30 seconds along the direction of wind flow, measuring the wind speed and wind temperature of the place, displaying the wind speed and wind temperature on a display screen and automatically inputting the wind speed and wind temperature;
(6) Clicking to enter a calculation mode to automatically calculate a convective heat transfer coefficient and heat flux density in a rock body, then calculating the heat quantity of the required wall surface of the surrounding rock of the roadway and the air current exchange, and calculating the temperature change of the air current to the surrounding rock of the roadway through a heat and temperature conversion formula;
(7) Clicking an icon of the infrared temperature measurement module, opening an infrared thermal imager in the device, aligning the front face of an infrared thermal imaging camera of the device with the wall surface of the surrounding rock of the roadway, standing the device for a period of time (about 30 seconds), displaying the infrared temperature value of the current wall surface of the surrounding rock of the roadway by a display screen of the device, automatically processing the temperature influence of the wind flow on the temperature wall surface, displaying the temperature field image of the wall surface of the surrounding rock of the roadway without wind influence, and automatically inputting the temperature value of each pixel of the temperature field image of the wall surface of the surrounding rock of the roadway;
(8) Clicking the icon of the infrared temperature measurement module again, putting a small test block in a mine hole in advance to a windless position, measuring the temperature value of the test block which is not influenced by stress under the windless condition by using an infrared thermal imager, calculating an average value and inputting the average value of the temperature;
(9) Clicking a stress field calculation icon, subtracting the infrared average temperature value of the test block which is not influenced by the stress from the temperature value of each pixel of the temperature field image of the roadway surrounding rock wall surface which is influenced by the stress, thereby calculating the stress tensor of each pixel, and displaying the stress field image of the roadway surrounding rock wall surface without wind influence in the infrared temperature image mode;
(10) And finally, carrying out rock burst evaluation, obtaining different alarm information according to different stress values, and judging the safety state of the roadway surrounding rock according to the alarm information.
In summary, it is a complicated task to calculate the heat exchange amount between the surrounding rocks of the roadway and the wind flow, because the heat exchange is time-varying and the rock formation is anisotropic. The traditional classical calculation method needs a large amount of numerical calculation and is a mathematical model established under a plurality of simplified and assumed conditions, and the calculation result is not necessarily reliable. The method estimates the change value of the heat flux density of the wall surface of the roadway by measuring the change value of the internal temperature of the surrounding rock of the roadway, can obtain the size of heat transfer quantity according to the heat flux density, and then can obtain the calculation relation between the heat transfer quantity of the surrounding rock of the roadway and wind current and the change value of one point or a plurality of points of the surrounding rock, so as to obtain the influence of the wind current in the roadway on the temperature of the surrounding rock of the roadway, and then remove the influence of the wind current on the temperature of the surrounding rock of the roadway, and only leave the temperature change of the surrounding rock of the roadway caused by the deformation of the surrounding rock of the roadway due to the stress.
In addition, the invention also designs a device capable of directly observing the stress condition of the surrounding rocks of the roadway, the study on the coupling thermodynamic numerical value of the temperature field change caused by the simulation of rock deformation is relatively rare at present, and no equipment for calculating the stress field by the temperature field of the surrounding rocks of the roadway exists at present, even no equipment capable of directly observing the stress field of the surrounding rocks of the roadway exists. According to the tunnel surrounding rock temperature field without the influence of the wind flow, the invention provides a novel, reliable and practical calculation method by combining the coupling thermodynamics of the temperature field change caused by the rock deformation and utilizing the relational expression between the temperature field change and the stress field obtained by the elastic thermal effect in the tunnel surrounding rock deformation process, and integrates a device for detecting the tunnel surrounding rock stress without the influence of the wind flow based on the infrared thermal imaging technology through the design of software and hardware, thereby predicting the occurrence of rock burst.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (7)
1. A roadway stress infrared monitoring method for solving the influence of wind current is characterized by comprising the following steps:
s1, acquiring thermophysical coefficients of surrounding rock of a roadway and roadway size parameters;
s2, calculating the radius of the heat regulation zone, and calculating to obtain the final heat flux density of the wall surface of the surrounding rock of the roadway by combining the original rock temperature and the temperature measurement value of a temperature measurement point in the surrounding rock of the roadway, so as to obtain the heat of heat exchange between the wind current and the surrounding rock of the roadway;
s3, calculating a temperature change value of the wind current to a roadway surrounding rock temperature field according to the corresponding relation between the heat and the temperature;
s4, measuring the temperature value of each pixel of an infrared temperature field of the wall surface of the surrounding rock of the roadway, which is influenced by the wind flow and the stress, and combining the temperature change value to finally obtain an infrared temperature field image of the wall surface of the surrounding rock of the roadway, which is not influenced by the wind flow and is only influenced by the stress;
and S5, obtaining the average temperature value of the test block without the influence of the wind current on the stress, calculating the difference value between each pixel of the infrared temperature field image on the wall surface of the surrounding rock of the roadway and the average temperature value of the test block, obtaining the stress tensor change of each pixel point through calculation, and finally converting the stress tensor change into the stress value of each pixel point.
2. The infrared tunnel stress monitoring method for solving the wind flow influence according to claim 1, wherein in step S1, the thermophysical coefficients include a thermal conductivity coefficient λ, a specific heat C, a density ρ, a thermal capacity cp and a thermal conductivity coefficient α, and the tunnel size parameters include a tunnel hydraulic radius r0 and a measured wall surface area S.
3. The infrared monitoring method for solving the roadway stress influenced by the wind current as recited in claim 2, wherein in the step S2, the radius rt = r of the heat regulation circle 0 +(r 0 2 +12αt) 1/2 Wherein the hydraulic radius of the roadway is r0, the temperature conductivity coefficient is alpha, and the time required by drilling and temperature measurement is t; and the calculated heat flux density of the wall surface of the surrounding rock of the roadway is Q, and the heat flux density Q is multiplied by the measured wall surface area S to obtain the heat quantity Q1 of the heat exchange between the wind current and the surrounding rock of the roadway.
4. The infrared tunnel stress monitoring method for solving the wind flow influence of claim 3, wherein in step S3, the corresponding relationship between heat and temperature is Q1= a (t 2-t 1) S, t1 is a temperature value only affected by stress in the absence of wind, t2 is a temperature value affected by stress in the presence of wind, a is a convective heat transfer coefficient, S is a measured wall surface area, and (t 2-t 1) is a temperature change value of the wind flow to the tunnel surrounding rock temperature field.
5. The infrared tunnel stress monitoring method for solving the wind flow influence according to claim 4, wherein the detailed process of the step S4 is as follows:
and measuring the temperature value of each pixel of the infrared temperature field of the wall surface of the surrounding rock of the roadway, which is influenced by the wind flow and the stress, by the thermal infrared imager, and subtracting the temperature change value (t 2-t 1) from the temperature value of each pixel to obtain the image of the infrared temperature field of the wall surface of the surrounding rock of the roadway, which is not influenced by the wind flow and the stress.
6. The infrared roadway stress monitoring method for solving the wind flow influence as claimed in claim 5, wherein in step S5, the relationship between the rock temperature change and the stress tensor change is as follows:
T0i-T00＝-T00×a/(ρ*Cρ)×Δδkk
wherein T0i is a pixel temperature value of an infrared temperature field image of the wall surface of the surrounding rock of the roadway, which is not influenced by the stress due to the absence of the wind flow, T00 is an average temperature value of a test block, which is not influenced by the stress due to the absence of the wind flow, a is a convective heat transfer coefficient, ρ is the density of the rock mass, Cρ is the thermal capacity of the rock mass, and Δ δ kk is the change of the stress tensor.
7. The roadway stress infrared monitoring device for solving the wind flow influence is characterized by comprising a thermal infrared imager, a laser ranging device and an ultrasonic wind speed and wind temperature measuring instrument, wherein an industrial control board is further arranged in the roadway stress infrared monitoring device and used for executing the roadway stress infrared monitoring method as claimed in any one of claims 1 to 6.
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| CN116740329B (en) * | 2023-06-20 | 2024-03-12 | 武汉工程大学 | Deep roadway rock burst prevention and control method based on infrared monitoring technology |
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