A method for detecting a shallow high temperature region

Abstract

The application discloses a method for detecting a shallow high-temperature area, which comprises the following steps: S1, first, surface exploration is carried out, and then a test grid is arranged and divided; S2, a radon measurement area center point is set, a radon measurement area is set with the radon measurement area center point as a center, and three gas sampling points are selected in the radon measurement area; S3, a radon measurement outer tube is inserted into the gas sampling points and fixed, a gas sampling rod is inserted into the radon measurement outer tube for gas sampling, then the three gas sampling rods are transmitted to a radon measurement instrument for radon value measurement, so that the radon value in the radon measurement area around the radon measurement area center point is obtained; S4, after all the radon measurement areas are measured, radon values are arranged in descending order according to average values; S5, a radon value three-dimensional contour map is drawn by using drawing software, a radon concentration distribution range, a radon concentration distribution form and a radon value anomaly center position are obtained, and finally a downhole high-temperature danger area range is demarcated, and the method has the advantages of reducing errors, data contrast and reference, improving radon value measurement precision and radon measurement efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of surface radon measurement, and particularly relates to a method for detecting a shallow high-temperature area. BACKGROUND

[0002] Due to a large number of small coal mines in the early stage of China, the mining is not standardized and the roadway data is incomplete, which leads to a fire in the underground goaf and difficulty in determining the fire location, and the coal spontaneous combustion has a great influence on the distribution of radon in the surrounding rock. The isotope surface radon measurement method can determine the range of the fire area in the shallow coal seam according to the radon distribution law.

[0003] The following problems exist at present: (1) The isotope radon measurement method needs to divide a grid first, and then detect at four intersection points of the grid, which leads to problems of long measurement point period, more measurement point arrangement, limited detection area range, and it is difficult to realize large-scale fire area detection, the unclear fire range leads to great difficulty in underground fire control, and affects the safety production of the mine; (2) Too many detection points will more easily cause large deviation values, which will lead to difficulty in directly determining the fire area boundary through the radon abnormal value boundary, and the development trend of the fire area is difficult to judge; (3) After the radon measurement work is completed, when the high-risk fire area is repeatedly measured and detected in the future, it is necessary to drill and take gas again, which is a large amount of work and time-consuming, and at the same time, due to the change of the gas taking point position, it is impossible to compare and refer to the previous radon data. SUMMARY

[0004] The application aims to provide a method for detecting a shallow high-temperature area, increase the gas taking points in a single radon measurement process, improve the radon measurement efficiency and accuracy, accurately determine the range of the shallow temperature abnormal area, and solve the problems that the isotope radon measurement method is difficult to realize large-scale fire area detection, too many detection points cause large deviation values, and the change of the gas taking point position cannot be compared with the previous radon data.

[0005] To this end, the technical scheme adopted by the application is as follows: a method for detecting a shallow high-temperature area, comprising the following steps:

[0006] Step S1, first, surface exploration is carried out, the suspected fire area range and the topographic features are recorded, and then the arrangement and division of the test grid in the suspected fire area coverage range are carried out;

[0007] Step S2, a radon measurement area midpoint is set every interval of the test grid, the radon measurement area midpoint coordinate position is determined on site by using a GPS and is recorded, a radon measurement area is set up with the radon measurement area midpoint as the center and tangent to the four sides of the corresponding test grid, then three gas taking points are selected in the radon measurement area, and pre-drilling is carried out at the gas taking points;

[0008] Step S3, insert the radon measuring outer tube into the gas sampling point, then insert the gas sampling rod into the radon measuring outer tube to sample gas, and then connect the three gas sampling rods to the drying tube through a four-way joint to dry and remove moisture; finally, the dried gas is transmitted to the radon measuring instrument for radon value measurement, so as to obtain the radon value in the radon measuring area around the measuring point, and after the measurement is completed, only the gas sampling rod is taken out and the radon measuring outer tube is sealed;

[0009] Step S4, according to steps S2-S3, the radon values in all radon measuring areas are measured in turn, and the radon value in each radon measuring area is divided by the number of gas sampling points in the corresponding radon measuring area to obtain the average value of the radon value at the measuring point in each radon measuring area, and finally the average value of the radon value is arranged in descending order to obtain the median value of the radon value, which is regarded as the representative value of the "normal radon value";

[0010] Step S5, a drawing software is used to draw a radon value three-dimensional contour map of the detection range, and the radon concentration distribution range, form and radon value anomaly center position are preliminarily obtained by analyzing the contour map, and the risk degree of different radon value ranges is classified; the radon value anomaly area is comprehensively analyzed, and the surface exploration situation is combined to finally demarcate the high-temperature danger area range underground.

[0011] As a preferred embodiment of the above scheme, in step S1, the surface exploration key detection positions are small cave openings, illegal mining points, open fire points, smoke points, ground subsidence areas, burned rocks, and coal outcrops, and high-density grids are arranged at the surface exploration key detection positions, and detection points are added in areas with high risk to ensure the accuracy of radon measurement and reduce the risk of missed measurement.

[0012] Further preferably, in step S2, the distance between adjacent radon measuring area center points is 20m-200m, and the number of radon measuring area center points is not less than 16, that is, the radius of the radon measuring area is 5m-100m, which is reasonable in size to improve the accuracy of radon anomaly value determination.

[0013] Further preferably, in step S2, after the gas sampling points are selected, the radon measuring area and the surrounding soil type, the on-site surface condition, and the weather condition of the engineering site within 24 hours before the test are recorded in detail, and when the radon measuring area center point deviates due to geological reasons, the new point coordinates are recorded in detail, and the radon measuring area center point arrangement diagram is updated, which is reasonable and accurate in measuring radon value.

[0014] Further preferably, in step S2, a soil drill rod is used to pre-drill a hole at the gas sampling point, and the uniform hole depth is 1m-1.5m, so as to eliminate the radon measurement error caused by the difference in hole depth, and then the soil drill rod is pulled out and inserted into the radon measuring outer tube, which is convenient and fast to operate.

[0015] Further preferably, in the step S3, a sealing fixing base is arranged at the top of the radon measuring outer tube, and a sealing cover capable of being screwed into the sealing fixing base is arranged, and after the gas sampling at the gas sampling point around the center point of the radon measuring area is completed, the sealing cover is screwed into the sealing fixing base to seal the radon measuring outer tube, which is simple and easy to operate, and the radon measurement does not need to be punched again for normal detection.

[0016] Further preferably, in the step S3, the three gas sampling rods, the four-way joint and the drying tube are sequentially connected through the hose, and the connection is convenient, the length of the hose is flexible, the weight is light, and the cost is low.

[0017] Further preferably, in the step S4, the variable value above the radon value median is compared and statistically analyzed with the radon value median to determine the reasonable representative interval of the representative value of the normal radon value, and since the judgment standard of the radon value anomaly only focuses on the abnormally large deviation value, the rationality of the radon value median can be ensured.

[0018] Further preferably, in the step S5, the drawing software adopts Surfer software, and the radon value range corresponding to the coal low-temperature oxidation, rapid oxidation and spontaneous combustion stage under the geological conditions of the test range is determined as the reference range for the risk level division, and the range of the fire area is not clear, and the measurement is supplemented, and the accuracy of the high-temperature danger area range division is further improved.

[0019] The beneficial effects of the present application are as follows:

[0020] (1) Compared with the current isotopic radon measurement method, it is difficult to realize large-scale fire area detection, and too many detection points appear large deviation values, the present scheme improves the detection point arrangement mode, changes the grid intersection single point into a radon measuring area with the center point of the radon measuring area as the center and the four edges of the corresponding test grid tangent, selects three gas sampling points in the radon measuring area, and greatly reduces the error caused by single point measurement through the obtained radon value average.

[0021] (2) Compared with the current isotopic radon measurement method, the position of the gas sampling point cannot be compared and referenced with the previous radon measurement data, the present scheme obtains the radon value in the radon measuring area around the center point of the radon measuring area, after the measurement is completed, only the gas sampling rod is taken out and the radon measuring outer tube is sealed, and the next time the gas sampling rod is inserted into the outer tube by opening the sealing cover, and in the future repeated radon measurement detection of the dangerous fire area, the drilling hole does not need to be repeated, the radon engineering amount is reduced, and since the gas sampling position is the same, the subsequent radon measurement data can be compared and referenced with the original data for analysis, and the design is ingenious.

[0022] (3) By arranging the radon measuring area, the original grid needs four separate measuring points, and now only one radon measuring area center point needs to be arranged, and the number can be reduced to 1 / 4 of the conventional point number, which greatly shortens the radon measurement period and provides technical support for improving the fire area detection area.

[0023] (4) Compared with the case that a large deviation value is easily generated in original single-point measurement, the three gas taking rods simultaneously transmit to the radon measuring instrument for radon value measurement, then the radon value of each radon measuring area is obtained by dividing the measured radon value in the radon measuring area by the number of the gas taking points in the corresponding radon measuring area, obviously, the influence of the large deviation value is neutralized, the measurement accuracy of the radon value is improved, and the radon measuring efficiency is also improved.

[0024] In summary, the present application has the advantages of reducing errors, data comparison and reference, improving the measurement accuracy of the radon value, and improving the radon measuring efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a schematic diagram of the arrangement of the present application.

[0026] Figure 2 It is a schematic diagram of the gas taking of the gas taking point.

[0027] Figure 3 It is a schematic diagram of the structure of the gas taking rod inserted into the radon measuring outer tube.

[0028] Figure 4 It is a schematic diagram of the structure of the sealing fixing seat.

[0029] Figure 5 It is a schematic diagram of the structure of the sealing cover. DETAILED DESCRIPTION

[0030] The present application will be further described below by examples and in conjunction with the drawings:

[0031] In conjunction with the drawings, Figure 1 — Figure 5 shown, a method for detecting a shallow buried high temperature area, comprising the following steps:

[0032] Step S1, first, surface exploration is performed, the suspected fire area range and the topographic features are recorded, then the arrangement and division of the test grid 1 in the suspected fire area coverage range are performed.

[0033] In step S1, the surface exploration key detection positions are small kiln openings, illegal mining points, open fire points, smoke points, ground subsidence areas, burned and altered rocks, and coal outcrops, and a high-density grid is arranged and divided at the surface exploration key detection positions.

[0034] Step S2, a radon measuring area midpoint 2 is set every interval of a test grid 1, and after the radon measuring area midpoint 2 coordinate position is determined on site by GPS, it is recorded, then a radon measuring area which is tangent to the four edges of the corresponding test grid 1 is set up with the radon measuring area midpoint 2 as the center, then three gas taking points 3 are selected in the radon measuring area, and the gas taking points 3 are pre-drilled.

[0035] The three gas taking points 3 are preferably located on the edge of the radon measuring area, and the three gas taking points 3 are uniformly dispersed and arranged.

[0036] In step S2, the distance between the adjacent radon measuring area points 2 is 20-200 m, the radon measuring area is a circular area with a radius of 5-50 m, and the number of radon measuring area points 2 is not less than 16.

[0037] In step S2, after selecting the gas sampling point 3, the radon measuring area and the surrounding soil type, the site surface condition, and the weather condition of the engineering site within 24 hours before the test are recorded in detail. When the radon measuring area point 2 deviates due to geological reasons, the new point coordinates are recorded in detail, and the radon measuring area point 2 layout diagram is updated.

[0038] In step S3, the radon measuring outer tube 4 is inserted into the gas sampling point 3 and fixed, then the gas sampling rod 5 is inserted into the radon measuring outer tube 4 for gas sampling, and then the three gas sampling rods 5 are connected to the drying tube 7 through the four-way joint 6 for drying and dehumidifying. Finally, the dried gas is transmitted to the radon measuring instrument 8 for radon value measurement, so as to obtain the radon value in the radon measuring area around the radon measuring area point 2. After the measurement is completed, only the gas sampling rod 5 is taken out and the radon measuring outer tube 4 is sealed.

[0039] In step S3, a soil drill rod is used to pre-drill a hole at the gas sampling point 3, and the uniform hole depth is 1-1.5 m. Then the soil drill rod is pulled out and the radon measuring outer tube 4 is inserted. The top of the radon measuring outer tube 4 is provided with a sealing and fixing seat 41, and is equipped with a sealing cover 42 which can be screwed into the sealing and fixing seat 41. After the gas sampling at the gas sampling point 3 around the radon measuring area point 2 is completed, the sealing cover 42 is screwed into the sealing and fixing seat 41 to seal the radon measuring outer tube 4.

[0040] In step S3, the three gas sampling rods 5, the four-way joint 6, the drying tube 7, and the radon measuring instrument 8 are connected in sequence through the hose 9.

[0041] In step S4, the radon values in all radon measuring areas in the test grid 1 are measured in sequence according to steps S2-S3. The radon value in each radon measuring area point 2 is obtained by dividing the number of radon measuring area points by the number of radon measuring area points. Finally, the radon value average is arranged in descending order, and the obtained radon value median is regarded as the representative value of the "normal radon value".

[0042] In step S4, the radon value above the radon value median is compared and statistically analyzed with the radon value median to determine the reasonable representative interval of the "normal radon value" representative value.

[0043] In step S5, a drawing software is used to draw a radon value three-dimensional contour map of the detection range. The radon concentration distribution range, form, and radon value anomaly center position are preliminarily obtained by analyzing the contour map, and the different radon value ranges are classified according to the risk degree. The radon value anomaly area is comprehensively analyzed, and the surface exploration situation is combined to finally demarcate the high temperature danger area range underground.

[0044] In step S5, the drawing software adopts Surfer software to determine the radon value range corresponding to the coal low-temperature oxidation, rapid oxidation and spontaneous combustion stage under the geological conditions of the test range, as the reference range for the hazard level division, and to supplement the measurement of the unclear range of the fire area.

[0045] A vertical borehole is arranged on the surface of the high-risk area and a temperature sensor is installed. By comparing the downhole temperature and radon value detection results, the direct relationship between the radon value and the downhole temperature in the area is established.

[0046] Therefore, when the fire area treatment is completed, the installed temperature sensor and the average radon value are used for continuous dynamic monitoring of the fire area, and can be used as a quantitative index for verifying the extinguishment of the fire area.

Claims

1. A method of detecting a shallow high temperature zone, characterized by, It comprises the following steps: Step S1, first carry out surface exploration, record the suspected fire area range and topographic features, then arrange and divide the test grid (1) in the suspected fire area coverage; Step S2, set a radon measurement area midpoint (2) every interval test grid (1), and record the radon measurement area midpoint (2) coordinate position determined by GPS in the field, then set up a radon measurement area which is tangent to the four edges of the corresponding test grid (1) with the radon measurement area midpoint (2) as the center, then select three gas sampling points (3) in the radon measurement area and pre-drill holes at the gas sampling points (3); Step S3, insert the radon measurement outer tube (4) into the gas sampling point (3) and fix it, then insert the gas sampling rod (5) into the radon measurement outer tube (4) to take gas, then connect the three gas sampling rods (5) to the drying tube (7) through the four-way joint (6) for drying and dehumidifying; finally, the dried gas is transmitted to the radon measurement instrument (8) for radon value measurement, so as to obtain the radon value in the radon measurement area around the radon measurement area midpoint (2), after the measurement is completed, only the gas sampling rod (5) is taken out and the radon measurement outer tube (4) is sealed; Step S4, according to steps S2-S3, sequentially measure all radon measurement areas, divide the measured radon value in the radon measurement area by the number of gas sampling points in the corresponding radon measurement area to obtain the average value of the radon value of each radon measurement area midpoint (2), finally arrange the average value of the radon value in descending order, and the obtained median value of the radon value is regarded as the "normal radon value" representative value; Step S5, draw a radon value three-dimensional contour map of the detection range by using drawing software, analyze the contour map to preliminarily obtain the radon concentration distribution range, form and radon value anomaly center position, and classify and divide the different radon value ranges according to the danger degree; comprehensively analyze the radon value anomaly area and combine the surface exploration situation to finally demarcate the high temperature danger area range underground.

2. A method of detecting a shallow high temperature zone as claimed in claim 1, wherein: In step S1, the key detection positions of surface exploration are small kiln openings, illegal mining points, open fire points, smoke points, ground collapse areas, burned and altered rocks, and coal outcrops, and high-density grids are arranged and divided at the key detection positions of surface exploration.

3. The method of claim 1, wherein: In step S2, the distance between adjacent radon measurement area midpoints (2) is 20-200 m, and the radon measurement area midpoints (2) are not less than 16.

4. The method of claim 1, wherein: In step S2, after the gas sampling points (3) are selected, the radon measurement area and the surrounding soil type, the field surface condition, and the weather condition of the engineering site within 24 hours before the test are recorded in detail, when the radon measurement area midpoint (2) deviates due to geological reasons, the new point coordinates are recorded in detail, and the radon measurement area midpoint (2) layout diagram is updated.

5. The method of claim 1, wherein: In step S2, the soil drill rod is used to pre-drill holes at the gas sampling points (3), and the uniform hole depth is 1-1.5 m.

6. The method of claim 1, wherein: In step S3, the radon measurement outer tube (4) is provided with a sealing fixing seat (41) at the top, and is provided with a sealing cover (42) which can be screwed into the sealing fixing seat (41), after the gas sampling at the gas sampling points (3) around the radon measurement area midpoint (2) is completed, the sealing cover (42) is screwed into the sealing fixing seat (41) to seal the radon measurement outer tube (4).

7. The method of claim 1, wherein: In step S3, the three gas sampling rods (5), the four-way joint (6), the drying tube (7), and the radon measurement instrument (8) are connected in sequence through the hose (9).

8. The method of claim 1, wherein: In the step S4, the variable values above the radon value median are compared with the radon value median for statistical analysis to determine a reasonable representative interval of the representative value of the "normal radon value".

9. The method of claim 1, wherein: In the step S5, the Surfer software is used to draw the radon value range corresponding to the coal low-temperature oxidation, rapid oxidation and spontaneous combustion stages under the geological conditions of the test range, as the reference range for the hazard level division, and the unconfirmed range of the fire area is supplemented.

Images