Optimal design method of blasting delay parameters based on thermal imaging and high-speed photography technology

Abstract

The present invention discloses a method for optimizing and designing blasting delay parameters based on thermal imaging and high-speed photography technology, including the steps of determining monitoring points, setting up instruments, capturing images, processing image data, extracting image data, processing data, and verifying the rationality of the delay time. The present invention has the beneficial effect of introducing high-speed photography and infrared thermal imaging technology into the field of engineering blasting. The infrared thermal imager is used to monitor on-site the crack propagation process of the surrounding rock mass during the explosion of explosives in the blasting area, as well as the dissipation form of high-temperature gas products generated by the detonation. The visible image data captured by the high-speed camera is then used to compare, analyze, evaluate, and optimize the blasting delay time parameters, thereby providing on-site technicians with a fast and reliable method for optimizing blasting parameters.

Description

Technical Field

[0001] The invention belongs to a parameter design technology applied to engineering blasting, in particular to a blasting delay parameter optimization design method based on thermal imaging and high-speed photography technology. Background Art

[0002] In recent years, with the rapid development of electronic technology, optical physics, image storage and infrared remote sensing technology, infrared thermal imaging technology based on converting the invisible light of temperature radiation into visible thermal images has also been widely used. Its main principle is to use an infrared thermal imager to detect the infrared radiation of the target object, and through signal processing, photoelectric conversion and other means, convert the temperature distribution image of the target object into a visible image. The operator uses the image color and hot spot tracking display function displayed on the screen to preliminarily judge the heating situation and fault location, and then confirm the problem with the help of rigorous analysis, which can improve the accuracy and efficiency of finding problems.

[0003] In engineering blasting projects such as open-pit bench blasting, tunnel blasting, and road cutting blasting, the blasting network delay time parameter has always been a key concern for engineers. It not only affects the intensity and propagation distance of blasting vibration, but also determines the duration of rock collision in the blasting area and the size of the blasted fragments. It is a key factor in generating blasting hazards and affecting blasting quality. Given the complex environment and limited space surrounding the blasting area, these two indicators must be strictly controlled. Industry technicians and researchers have conducted extensive statistical analysis of basic data such as blasting vibration, fragmentation, blast pile uplift, over-excavation, and under-excavation at different delay times, using trial and error to determine the optimal network delay time for the blasting area. While this method ultimately achieves significant optimization results, it requires a long test cycle and relies heavily on blasting results as a reference. It also ignores process factors such as the energy propagation mode, rock cracking and fragmentation behavior, and the escape form of explosive gases during the explosive explosion. To this end, it is necessary to use existing high-speed photography, infrared photography and electronic technology to collect, analyze and verify the delay time and blasting effect during the actual blasting process, so as to clarify the process factors affecting the blasting effect and shorten the verification cycle. Summary of the Invention

[0004] The purpose of the present invention is to address the problems in the existing blasting engineering field, where the network delay time is determined based on the final blasting effect and empirical data, resulting in a long data acquisition cycle and unclear process factors. The present invention provides a blasting delay parameter optimization design method based on thermal imaging and high-speed photography technology. The method introduces high-speed photography and infrared thermal imaging technology into the field of engineering blasting. By using infrared thermal imagers, the crack propagation process of the surrounding rock mass during the explosion of explosives in the blasting area and the escape form of high-temperature gas products generated by the detonation are monitored on-site. The visible image data captured by the high-speed camera are then used for comparison, analysis, evaluation and optimization of the blasting delay time parameters. This provides on-site technicians with a fast and reliable means of blasting parameter optimization.

[0005] To achieve the aforementioned objectives, the present invention adopts the following technical solutions.

[0006] A method for optimizing blasting delay time parameters based on thermal imaging and high-speed photography technology includes the following steps:

[0007] S1. Determination of monitoring points: Based on the blasting design parameters and surrounding environmental data of the blasting area, determine the photography boundary according to the size of the blasting area and set monitoring points on the open surface of the blasting area, and measure the position coordinates of the photography boundary and monitoring points;

[0008] S2. Instrument setup: Calculate the instrument setup location based on the parameter characteristics of the high-speed camera and infrared thermal imager, the photography boundary, and the coordinates of the monitoring point. Set up the high-speed camera and infrared thermal imager according to the calculation results, and complete the shooting parameter setting.

[0009] S3. Image capture: Synchronously start the high-speed camera and infrared thermal imager to capture visible images and infrared thermal image data of the rock mass in the blasting area and the surrounding surface rock mass being broken and moved by the explosives during the blasting process in the target blasting area;

[0010] S4. Image data processing: The video streams of the obtained image data are respectively imported into analysis software that matches the corresponding video stream format for decomposition to obtain single-frame visible light images and single-frame infrared thermal images;

[0011] S5. Image data extraction: including extracting the rock mass displacement y and the corresponding time t at the measuring point from the single-frame visible light image; and extracting the detonation gas product color block area A and the corresponding time t at the measuring point where the detonation gas product is different from the ambient infrared thermal image from the single-frame infrared thermal image.

[0012] S 6. Data processing: Through nonlinear function fitting, the relationship function y(t) between rock displacement y and time t and the relationship function A(t) between infrared thermal imaging area A and time t are obtained respectively;

[0013] S7. Verification of rationality of delay time: Based on the relationship function y(t) and the relationship function A(t), inversion is performed to obtain the optimal time for rock crushing, and compared with the blasting design delay time TN to verify the rationality of the blasting design delay time.

[0014] The present invention adopts the above-mentioned technical solution, by introducing high-speed photography and infrared thermal imaging technology into the field of engineering blasting, using infrared thermal imagers to monitor on-site the crack expansion process of the surrounding rock mass during the explosion of explosives in the blasting area and the form of the escape of high-temperature gas products generated by the explosion, and combining the visible image data taken by the high-speed camera to compare, analyze, evaluate and optimize the blasting delay time parameters, thereby providing on-site technicians with a fast and reliable means of blasting parameter optimization. It is specifically manifested in the following aspects: (1) With the advantage of high-speed photography and infrared thermal imagers, the overall situation of the blasting area at the moment of explosive detonation can be monitored remotely and non-contactly, and the image digitization software is used to extract and quantitatively analyze the blasting characteristic parameters of the acquired image data, making the analysis results more reliable and more accurate, and greatly reducing the labor intensity of manually collecting and analyzing blasting parameters on-site. (2) It overcomes the defect that traditional instruments and equipment cannot capture the gas dissipation and energy growth and attenuation process of the explosion at the moment of blasting. The infrared thermal imager can present the energy development process of the blasting zone and the concentration of the high-temperature gas ejected in a full-scale and intuitive color image on the display screen. It is convenient for technicians to calculate the relative energy utilization rate based on the color range, thereby discovering the defects in the blasting parameter design and optimizing the blasting in a targeted manner. The optimization methods and means are more scientific and reasonable. (3) The infrared thermal imager can also be used in dark nights, rain, snow, fog and other harsh environments. It can complement the high-speed photography that cannot effectively monitor the overall situation of the blasting zone under harsh conditions.

[0015] The high-speed camera and infrared thermal imager are both mounted on a tripod. The blasting design parameters of the blasting area mainly include the step height H, the minimum resistance line W, and the network delay time T. D , the maximum charge per hole Q, the number of blastholes N, etc.; surrounding environmental data including ambient temperature. When demarcating the photography boundary, setting control points, and monitoring points, the photography boundary should be based on the geographical location and size of the blasting area. The photography boundary should be larger than the blasting area boundary. Three monitoring points are selected as feature parameter extraction targets on the open surface of the blasting area corresponding to the minimum resistance line of the first row of blastholes. The monitoring points are marked with brightly colored paint. Before shooting, the infrared thermal imager must also input the ambient temperature, the infrared absorption band of the rock, and the infrared emissivity of the explosive detonation mixture. At the same time, care should be taken to avoid atmospheric windows, otherwise the gas thermal image cloud cannot be effectively captured.

[0016] Preferably, in step S2, the instrument installation point is set in front of the open surface of the blasting area, and the instrument installation distance L is calibrated according to the following formula;

[0017] L=max(R f , R v , R d );

[0018] Where R f The horizontal flying distance of the blasting rocks, usually press R f =max(20n 2 W, 100K1K2r 3 / W) value; where n is the blasting funnel effect index, W is the minimum resistance line of the first row of blastholes, K1 is the deep hole density coefficient, K2 is the correlation coefficient between the explosive blast energy and the resistance line, selected from the table below, and the values ​​between the values ​​listed in the table are obtained by linear interpolation method, and r is the blasthole radius;

[0019] Table of correlation coefficient K2 between explosive blast energy and resistance line:

[0020]

[0021] R v R is the horizontal distance from the earthquake source when the maximum blasting vibration velocity is 1 cm / s and the vibration frequency is less than 15 Hz; d The optimal imaging horizontal distance of the instrument pixel points;

[0022] The elevation of the installation point of the high-speed camera and infrared thermal imager is H L Between H bottom and H top Among them, H bottom is the elevation of the step bottom plate; H top is the elevation of the top surface of the step; H top =H bottom +H, H is the step height;

[0023] The separation distance (S) between the high-speed camera and the infrared thermal imager is determined by the following formula:

[0024] S≤kL, where

[0025] This ensures clear video data is obtained under instrument safety conditions, laying a solid foundation for further analysis and verification. If the two instruments are too far apart, the angles at which they capture images will vary significantly, resulting in poor data accuracy at the same measurement point and affecting interpretation. Furthermore, manual instrument setup and storage is time-consuming and inconvenient.

[0026] Preferably, in the parameter setting of step S2 and the image shooting of step S3, the high-speed camera and the infrared thermal imager are both shot for the same total shooting time T. t and the same starting time Ts The starting time difference ΔT between the two is determined by the following formula:

[0027] ΔT=|T s红 -T s高 |≤1s;

[0028] Where, T s红 is the starting time of the infrared thermal imager; T s高 is the shooting start time of the high-speed camera.

[0029] This ensures that two images taken at the same moment are selected for comparative analysis during video data processing, striving to make the analysis results more accurate.

[0030] Furthermore, preferably, in step S3, the high-speed camera and the infrared thermal imager both start shooting synchronously via satellite timing. By using the satellite timing method, the difference in the start time of the two instruments set up at almost the same shooting position is eliminated, and the purpose of simultaneous shooting is achieved.

[0031] Preferably, in the data processing of step S6, the characteristic parameters extracted from the single-frame images of the high-speed camera and the infrared thermal imager are respectively converted into the form of y=k0+k1*t+k2*e by the nonlinear function fitting. -1 / t and A=b0+b1*t+b2*e -1 / t Perform fitting, obtain the correlation coefficient, and obtain the time t when the rock starts to move 0高 and the infrared cloud image generation start time t 0红 Then, the above formulas are derived to obtain the rock mass movement acceleration time t 1高 and gas expansion acceleration time t 1红 , and max(t 0高 +t 1高 , t 0红 +t 1红 ) as the optimal micro-difference delay time. The process simulation and analysis are performed with the help of existing mathematical analysis methods to ensure the accuracy of the optimal micro-difference delay time.

[0032] Further preferably, in the delay time rationality verification of step S7, the optimal micro-difference delay time is compared with the blasting design delay parameter T D Calculate the range and compare it with the predetermined verification standard. D -max(t 0高 +t 1高 , t 0红 +t 1红 )| is less than or equal to the pre-set verification standard time, the micro-difference time is considered reasonable and there is no need to optimize the delay time of the blasting design; when |T D -max(t 0高 +t1高 , t 0红 +t 1红 If the delay time is greater than the pre-set verification standard time, the micro-difference time is considered unreasonable and the delay time should be optimized. Comparison and judgment determine the need for improvement. The pre-set verification standard time is 1ms. This is determined based on the blasting type and delay characteristics, using empirical data, to ensure blasting effectiveness.

[0033] The beneficial effect of the present invention is that it introduces high-speed photography and infrared thermal imaging technology into the field of engineering blasting. By using the infrared thermal imager, the crack expansion process of the surrounding rock mass during the explosion of explosives in the blasting area and the escape form of high-temperature gas products generated by the detonation are monitored on-site. The visible image data taken by the high-speed camera are combined to compare, analyze, evaluate and optimize the blasting delay time parameters, thereby providing on-site technicians with a fast and reliable means of blasting parameter optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a flow chart of the present invention.

[0035] Figure 2 It is a planar layout diagram of control points and camera positions in the present invention.

[0036] Figure 3 It is a schematic diagram of the parameters of the free surface of the step in the present invention.

[0037] In the attached figure: 1-infrared thermal imager; 2-high-speed camera; 3-tripod; 4-photography boundary control point; 5-monitoring point; 6-photography boundary; 7-blast hole; 8-air surface. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited to the scope of the embodiments described.

[0039] See also Figure 1 、 Figure 2 and Figure 3 A method for optimizing blasting delay time parameters based on thermal imaging and high-speed photography technology comprises the following steps:

[0040] S1. Determination of monitoring points: Based on the blasting design parameters and surrounding environmental data of the blasting area, determine the photography boundary according to the size of the blasting area and set monitoring points on the open surface of the blasting area, and measure the position coordinates of the photography boundary and monitoring points;

[0041] S2. Instrument setup: Calculate the instrument setup location based on the parameter characteristics of the high-speed camera 2 and the infrared thermal imager 1, the photographic boundary, and the coordinates of the monitoring point 5, and set up the high-speed camera and infrared thermal imager according to the calculated results, and complete the shooting parameter setting.

[0042] S3. Image capture: Synchronously start the high-speed camera and infrared thermal imager to capture visible images and infrared thermal image data of the rock mass in the blasting area and the surrounding surface rock mass being broken and moved by the explosives during the blasting process in the target blasting area;

[0043] S4. Image data processing: The video streams of the obtained image data are respectively imported into analysis software that matches the corresponding video stream format for decomposition to obtain single-frame visible light images and single-frame infrared thermal images;

[0044] S5. Image data extraction: including extracting the rock mass displacement y and the corresponding time t at the measuring point from the single-frame visible light image; and extracting the detonation gas product color block area A and the corresponding time t at the measuring point where the detonation gas product is different from the ambient infrared thermal image from the single-frame infrared thermal image.

[0045] S6. Data processing: Through nonlinear function fitting, the relationship function y(t) between rock displacement y and time t and the relationship function A(t) between infrared thermal imaging area A and time t are obtained respectively;

[0046] S7. Verification of rationality of delay time: Based on the relationship function y(t) and the relationship function A(t), the optimal time for rock crushing is obtained and compared with the blasting design delay time T. N Compare the results to verify the rationality of the blasting design delay time.

[0047] Among them, high-speed cameras and infrared thermal imagers are both set up with the help of tripods.

[0048] In step S2, the instrument installation point is set in front of the open surface of the blasting area, and the instrument installation distance L is calibrated according to the following formula;

[0049] L=max(R f , R v , R d );

[0050] Where R f The horizontal distance of flying rocks from blasting, usually press R f =max(20n 2 W, 100K1K2r 3 / W) value; where n is the blasting funnel effect index, W is the minimum resistance line of the first row of blastholes, K1 is the deep hole density coefficient, K2 is the correlation coefficient between the explosive blast energy and the resistance line, selected from the table below, and the values ​​between the values ​​listed in the table are obtained by linear interpolation method, and r is the blasthole radius;

[0051] Table of correlation coefficient K2 between explosive blast energy and resistance line:

[0052]

[0053] R v R is the horizontal distance from the earthquake source when the maximum blasting vibration velocity is 1 cm / s and the vibration frequency is less than 15 Hz; d The optimal imaging horizontal distance of the instrument pixel points;

[0054] The elevation of the installation point of the high-speed camera and infrared thermal imager is H L Between H bottom and H top Among them, H bottom is the elevation of the step bottom plate; H top is the elevation of the top surface of the step; H top =H bottom +H, H is the step height;

[0055] The separation distance S between the high-speed camera and the infrared thermal imager is determined by the following formula:

[0056] S≤kL, where

[0057] In the parameter setting of step S2 and the image shooting of step S3, the high-speed camera and the infrared thermal imager are both shot for the same total shooting time T. t and the same starting time T s The starting time difference ΔT between the two is determined by the following formula:

[0058] ΔT=|T s红 -T s高 |≤1s;

[0059] Where, T s红 is the starting time of the infrared thermal imager; T s高 is the shooting start time of the high-speed camera.

[0060] In the image shooting of step S3, the high-speed camera and the infrared thermal imager both start shooting synchronously through satellite timing.

[0061] In the data processing of step s6, the characteristic parameters extracted from the single-frame images of the high-speed camera and the infrared thermal imager are respectively converted into y=k0+k1*t+k2*e by the nonlinear function fitting. -1 / t and A=b0+b1*t+b2*e -1 / t Perform fitting, obtain the correlation coefficient, and obtain the time t when the rock starts to move 0高 and the infrared cloud image generation start time t 0红 Then, the above formulas are derived to obtain the rock mass movement acceleration time t 1高 and gas expansion acceleration time t 1红, and max(t 0高 +t 1高 , t 0红 +t 1红 ) as the optimal micro-difference delay time. In the delay time rationality verification of step S7, the optimal micro-difference delay time is compared with the blasting design delay parameter T D Calculate the range and compare it with the predetermined verification standard. D -max(t 0高 +t 1高 , t 0红 +t 1红 )| is less than or equal to the pre-set verification standard time, the micro-difference time is considered reasonable and there is no need to optimize the delay time of the blasting design; when |T D -max(t 0高 +t 1高 , t 0红 +t 1红 )|When it is greater than the pre-set verification standard time, the micro-difference time is considered unreasonable and the extension time should be optimized; wherein the pre-set verification standard time is 1ms.

[0062] The following uses the open-pit deep-hole bench blasting excavation in an open-pit mine as an example to further illustrate the application of the aforementioned blasting delay parameter optimization design method based on thermal imaging and high-speed photography technology.

[0063] The mine's rock type is limestone, and the on-site ambient temperature is 28°C, with no interference from rain, fog, or clouds. The high-speed camera used has a shooting speed of 300 to 500 fps. The handheld infrared thermal imager used has a resolution of 384 x 288 pixels, a field of view of 25° x 19°, a temperature measurement range of -20°C to 650°C, and a focal length of f15.

[0064] The optimization design method of blasting delay time parameters based on thermal imaging and high-speed photography technology has the following specific implementation steps:

[0065] The first step is to determine the monitoring points: Based on the blasting design parameters and surrounding environmental data of the blasting area, the photographic boundary 6 is determined according to the size of the blasting area delineated by the blasting area boundary 4, and monitoring points 5 are set on the open surface 8 of the blasting area. The position coordinates of the photographic boundary 6 and the monitoring points 5 are measured;

[0066] The blasting design data of the blasting area include: the elevation of the bottom plate of the step is 768m, the elevation of the top plate is 780m, the height of the step is 12m, the minimum resistance line is 3m, the diameter of the blast hole 7 is 160mm, the total number of holes is 43, the blast hole spacing is 6m, the row spacing is 4m, the hole depth is 14~14.5m, and mixed ammonium nitrate explosives are used. The charge of the front row single hole is 135kg, the blocking length is 5m, the reverse detonation is carried out hole by hole, the delay between holes is 17ms, and the delay between rows is 42ms. The overall environment of the blasting area is good and there is no slag pressure.

[0067] According to the hole row spacing, it can be calculated that the blasting area is 86m long, 57m wide and 12m high. The photography area is divided and positioned according to this boundary, and one point is selected as the control point at the left and right boundaries and the upper and lower boundaries of the step blasting area facing the air surface; the monitoring point is set at the minimum resistance line corresponding to the front row of blast holes, that is, 2.5m above the bottom plate elevation. In order to ensure the authenticity and reliability of the acquired data and eliminate the error of a single monitoring point, three blast holes are selected as observation objects. The above control points and monitoring points are marked with red paint.

[0068] The second step is instrument setup: the instrument setup point locations are calculated based on the parameter characteristics of the high-speed camera 2 and the infrared thermal imager 1, the photographic boundary, and the coordinates of the monitoring point. The high-speed camera 2 and the infrared thermal imager 1 are respectively set up using a tripod 3 according to the calculated results, and the shooting parameters are set.

[0069] The flying rock distance Rf is 29.4m, the horizontal distance Rv at a maximum blasting vibration velocity of 1cm / s is 144.82m, and the distance Rd required for the infrared thermal imager and high-speed camera to clearly capture the imaging boundary within the lens is 183m. Therefore, the safe distance L from the horizontal instrument installation point is at least 183m. The instrument installation height is the sum of the elevation of the step bottom plate and the tripod, which is EL.769.5m. The separation distance S between the infrared thermal imager and the high-speed camera is 2m, and the line connecting the two instruments is parallel to the top line of the slope.

[0070] The shooting parameters were set, including the high-speed camera with a shooting frame rate of 500 fps / s, a 2X shutter, a resolution of 1280×1024, a focal length of 28 mm, and a sampling time of 15 s; the infrared thermal imager with a shooting frame rate of 250 fps / s, a resolution of 768×576, an input environment of 28°C, an infrared rock infrared emissivity of 0.9, and a sampling time of 15 s.

[0071] Step 3: Image capture: Synchronously start the high-speed camera and infrared thermal imager to capture visible and infrared thermal image data of the rock mass in the blasting area and the surrounding surface rock mass breaking and moving under the action of the explosives during the detonation process in the target blasting area.

[0072] Step 4: Image data processing: The video streams of the obtained image data are imported into the analysis software that matches the corresponding video stream format for decomposition to obtain single-frame visible light images and single-frame infrared thermal images;

[0073] The fifth step is image data extraction, which includes extracting the rock mass displacement y and the corresponding time t at the measuring point from the single-frame visible light image; and extracting the detonation gas product color block area A and the corresponding time t at the measuring point where the measuring point and the ambient infrared thermal image show differences from the single-frame infrared thermal image.

[0074] Step 6. Data processing: Through nonlinear function fitting, the relationship function y(t) between rock displacement y and time t and the relationship function A(t) between infrared thermal imaging area A and time t are obtained respectively.

[0075] The relationship between rock displacement and time at the measuring point was extracted, and parameter fitting was performed to obtain y = -15.66 + 0.0084t + 15.6929e-1 / t. The full-frame video stream obtained by the infrared thermal imager was imported into professional thermal imaging analysis software. The relationship between the area of ​​the thermal imaging color block at the measuring point and time was also extracted, and parameter fitting was performed to obtain A = -17.33 + 0.0074t + 13.8834e-1 / t.

[0076] Step 7. Verify the rationality of the delay time: Based on the relationship function y(t) and the relationship function A(t), perform inversion to obtain the optimal time for rock crushing and compare it with the blasting design delay time T. N Compare the results to verify the rationality of the blasting design delay time.

[0077] During inversion, let y and A be equal to 0, and calculate the critical time t from the detonation of explosives to the rock mass not moving or about to move. 0高 =2.1ms and t 0红 = 2.23ms, and the duration of rock throwing and gas expansion acceleration is t 1高 =6ms and t 1红 =6.3ms, then the optimal delay time is max(t 0高 +t 1高 , t0 red + t 1红 ) = 8.53ms. Compared with the designed blasting delay time of 17ms, the difference is 8.47ms>1ms, indicating that the delay time is extremely unreasonable and the network delay time needs to be improved.

[0078] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A method for optimizing the blasting delay time parameters based on thermal imaging and high-speed photography technology, characterized in that: The following steps are involved: S1. Determination of monitoring points: Based on the blasting design parameters and surrounding environmental data of the blasting area, determine the photography boundary according to the size of the blasting area and set monitoring points on the open surface of the blasting area, and measure the position coordinates of the photography boundary and monitoring points; S2. Instrument setup: Calculate the instrument setup location based on the parameter characteristics of the high-speed camera and infrared thermal imager, the photography boundary, and the coordinates of the monitoring point. Set up the high-speed camera and infrared thermal imager according to the calculation results, and complete the shooting parameter setting. The instrument installation point is set in front of the open surface of the blasting area, and the instrument installation distance (L) is calibrated according to the following formula; L=max(R f ,R v ,R d ); Where R f is the horizontal scattering distance of blasting flying rocks; R v R is the horizontal distance of the earthquake source when the maximum blasting vibration velocity is 1 cm / s and the vibration frequency is less than 15 Hz; d The optimal imaging horizontal distance of the instrument pixel points; S3. Image capture: Synchronously start the high-speed camera and infrared thermal imager to capture visible images and infrared thermal image data of the rock mass in the blasting area and the surrounding surface rock mass being broken and moved by the explosives during the blasting process in the target blasting area; S4. Image data processing: The video streams of the obtained image data are respectively imported into analysis software that matches the corresponding video stream format for decomposition to obtain single-frame visible light images and single-frame infrared thermal images; S5. Image data extraction: including extracting the rock mass displacement y and the corresponding time t at the measuring point from the single-frame visible light image; and extracting the detonation gas product color block area A and the corresponding time t at the measuring point where the detonation gas product is different from the ambient infrared thermal image from the single-frame infrared thermal image. S6. Data processing: Through nonlinear function fitting, the relationship function y(t) between rock displacement y and time t and the relationship function A(t) between infrared thermal imaging area A and time t are obtained respectively; S7. Verification of rationality of delay time: Based on the relationship function y(t) and the relationship function A(t), the optimal time for rock crushing is obtained and compared with the blasting design delay time T. N Compare the results to verify the rationality of the blasting design delay time.

2. The method according to claim 1, characterized in that In step S2, the R f Press R f =max(20n 2 W, 100K1K2r 3 / W) value; where n is the blasting funnel effect index, W is the minimum resistance line of the first row of blastholes, K1 is the deep hole density coefficient, K2 is the correlation coefficient between the explosive blasting energy and the resistance line, and is selected from the table below. The values ​​between the values ​​listed in the table are obtained by linear interpolation method, and r is the blasthole radius; Table of correlation coefficient K2 between explosive blast energy and resistance line: The elevation of the installation point of the high-speed camera and infrared thermal imager is H L Between H bottom and H top Among them, H bottom is the elevation of the step bottom plate; H top is the elevation of the top surface of the step; H top =H bottom +H, H is the step height; The separation distance (S) between the high-speed camera and the infrared thermal imager is determined by the following formula: S≤kL, where .

3. The method according to claim 1, characterized in that In the parameter setting of step S2 and the image shooting of step S3, the high-speed camera and the infrared thermal imager are both shot for the same total shooting time T. t and the same starting time T s The starting time difference (ΔT) between the two is determined by the following formula: ΔT=|T s红 -T s高 |≤1s; Where, T s红 is the starting time of the infrared thermal imager; T s高 is the shooting start time of the high-speed camera.

4. The method according to claim 3, characterized in that During the image capture in step S3, the high-speed camera and the infrared thermal imager both start shooting synchronously through satellite timing.

5. The method according to any one of claims 1 to 4, characterized in that In the data processing of step S6, the characteristic parameters extracted from the single-frame images of the high-speed camera and the infrared thermal imager are respectively converted into y=k0+k1*t+k2*e by the nonlinear function fitting. -1 / t and A=b0+b1*t+b2*e -1 / t Perform fitting, obtain the correlation coefficient, and obtain the time t when the rock starts to move 0高 and the infrared cloud image generation start time t 0红 Then, the above formulas are derived to obtain the rock mass movement acceleration time t 1高 and gas expansion acceleration time t 1红 , and max(t 0高 +t 1高 , t 0红 +t 1红 ) as the optimal micro-difference extension time.

6. The method according to claim 5, characterized in that In the delay time rationality verification of step S7, the optimal delay time is compared with the blasting design delay parameter T D Calculate the range and compare it with the predetermined verification standard. D -max(t 0高 +t 1高 , t 0红 +t 1红 )| is less than or equal to the pre-set verification standard time, the micro-difference time is considered reasonable and there is no need to optimize the delay time of the blasting design; when |T D -max(t 0高 +t 1高 , t 0红 +t 1红 )|When it is greater than the pre-set verification standard time, the micro-difference time is considered unreasonable and the extension time should be optimized.

7. The method according to claim 6, characterized in that The preset verification standard time is 1 ms.

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