A gypsum mine subsidence monitoring system and assembly method

Abstract

The invention discloses a gypsum mine collapse monitoring system and a method for assembling the system, comprising a borehole, a monitoring sensor, a demodulation device, a monitoring platform, and a buzzer; a plurality of boreholes are independently arranged at various monitoring positions in a goaf area; a monitoring sensor is arranged in a borehole; a demodulation device is arranged in a safe area; the demodulation device is connected to the monitoring sensor and uploads monitoring data to monitoring software of a monitoring platform so as to issue a prejudgment alarm; a buzzer is installed at a surface position of a monitoring point and is connected to the demodulation device; the monitoring sensor comprises a fiber grating displacement meter, a fiber grating piezometer, a geological disaster alarm, and a seismic detector; the buzzer issues an on-site alarm according to a signal of the geological disaster alarm; the monitoring sensor monitors multiple parameters of the geology of the goaf area, collects comprehensive data, realizes all-round monitoring, and simultaneously provides prejudgment alarms and on-site alarms, so as to help operators quickly make timely response measures to dangerous geological conditions.

Description

Technical Field

[0001] The invention relates to the technical field of gypsum mine subsidence monitoring, and in particular to a gypsum mine subsidence monitoring system and a construction method thereof. Background Art

[0002] Gypsum is a widely used industrial and construction raw material, mostly found underground. China's gypsum resources are very rich and widely distributed, with a total reserve of more than 57.6 billion tons, ranking first in the world. With the advancement of urbanization in my country, the construction and decoration industries have developed rapidly, providing a broad space for the development of the gypsum industry, and the market capacity has continued to expand. While the large-scale mining of gypsum mines has brought economic benefits, it has also left serious risks of ground collapse in the goaf. Therefore, it is of great practical significance to carry out monitoring work in the goaf of gypsum mines.

[0003] Traditionally, soil deformation monitoring in goaf areas uses methods such as theodolite, level, steel ruler, span ruler, total station or GPS. These methods have poor real-time performance and are all based on monitoring the existing phenomenon of surface collapse. They are difficult to meet the requirements of advance prediction, long-term and real-time online monitoring of goaf areas. Therefore, it is impossible to evaluate and predict the change law of goaf stability and its development trend based on the deformation and movement of the goaf collapse area, so as to achieve the purpose of preventing and controlling disasters in goaf collapse areas. Summary of the invention

[0004] The main technical problem to be solved by the present invention is to provide a gypsum mine subsidence monitoring system and a construction method, which can perform long-term stability monitoring and issue prejudgment alarms and on-site alarms.

[0005] In order to solve the above-mentioned main technical problems, the following technical solutions are adopted:

[0006] A gypsum mine collapse monitoring system comprises a borehole, a monitoring sensor, a demodulation device, a monitoring platform and a buzzer; a plurality of the boreholes are independently arranged at various monitoring positions in a goaf; the monitoring sensor is arranged in a borehole; the demodulation device is arranged in a safe area and corresponds to the boreholes one by one; a plurality of the demodulation devices are correspondingly connected to the monitoring sensors through jumpers and the monitoring data of each monitoring point is uploaded to the monitoring software of the monitoring platform for comparison and analysis, and an independent prejudgment alarm is issued for each monitoring point; the buzzer is installed at the surface position of the monitoring point and is correspondingly connected to the demodulation device one by one; wherein the monitoring sensor comprises a fiber grating displacement meter, a fiber grating osmometer, a geological disaster alarm and a seismic detector; a plurality of the fiber grating displacement meters are connected in series along the axial direction of the borehole to form a U-shaped loop structure; a plurality of the seismic detectors are connected in parallel and are distributed in the borehole in a staggered manner; the buzzer can issue an on-site alarm according to the signal transmitted from the geological disaster alarm to the demodulation device.

[0007] Preferably, a counterweight is sunk at the bottom of the borehole; the counterweight is fixedly connected to the bottom optical fiber cable of the fiber grating displacement meter, the fiber grating osmometer, the geological disaster alarm, and the seismic detector.

[0008] Preferably, the demodulation device is powered by a solar power supply system.

[0009] Preferably, the U-shaped loop structure comprises two in parallel.

[0010] Preferably, the monitoring sensor further comprises a fiber Bragg grating thermometer for temperature compensation of the fiber Bragg grating piezometer; the fiber Bragg grating thermometer is at the same depth as the borehole where the fiber Bragg grating piezometer is located.

[0011] Preferably, a wireless transmission module is provided in the demodulation device.

[0012] Preferably, the prejudgment alarm includes a vertical settlement alarm, a groundwater level alarm, and a ground collapse vibration alarm.

[0013] A method for building a gypsum mine subsidence monitoring system comprises the following steps:

[0014] S1: Drill a hole at each pre-determined monitoring position around the goaf of the gypsum mine, with the depth of the hole being 1m above the bedrock; deploy a demodulation device corresponding to the hole in a safe area near the hole, and deploy a buzzer corresponding to the hole near the goaf where the hole is located;

[0015] S2: Select a counterweight block with appropriate weight and material, and ensure that the counterweight block is compatible with the inner diameter of the borehole; connect several fiber Bragg grating displacement meters in series to form a U-shaped loop structure, and fix the lowest position of the U-shaped loop structure on the top surface of the counterweight block; wrap the fiber Bragg grating piezometer with gauze and fix it to the counterweight block; fix the seismic detector and geological disaster alarm to the counterweight block;

[0016] S3: Lower the counterweight block equipped with the monitoring sensor to the end surface at the bottom of the borehole and ensure the horizontal stability of the counterweight block itself;

[0017] S4: Keep the optical fiber cables where the fiber Bragg grating displacement meter, fiber Bragg osmometer, geological disaster alarm, and seismic detector are located vertically and in a tight state, backfill the fine sand around the gypsum mine into the borehole, and ensure that the borehole is backfilled tightly;

[0018] S5: Connect the optical grating extending out of the borehole at the top of the monitoring sensor to the demodulation device through a jumper, and bury the optical grating extending out of the borehole on the surface;

[0019] S6: electrically connect the demodulation device to the solar power supply system; connect the demodulation device to the buzzer through a jumper, and bury the jumper on the surface;

[0020] S7: Start monitoring and use the effective initial monitoring value as the monitoring benchmark; in subsequent continuous monitoring, use the initial monitoring value as a reference for analysis; the monitoring platform will display the analyzed monitoring attempts and data, and issue a predictive alarm in a timely manner.

[0021] Preferably, in step S3, the monitoring sensor includes a fiber grating thermometer; the depth of the borehole where the fiber grating thermometer is located is consistent with the depth of the borehole where the fiber grating piezometer is located; the bottom of the fiber grating where the fiber grating thermometer is located is connected to the counterweight block, and the light grating extending out of the borehole at the top is fused with the demodulation device.

[0022] Compared with the prior art, the present invention has the following advantages when applied to monitoring of gypsum mine subsidence:

[0023] Monitoring based on fiber optic sensing technology has the advantages of low cost, high accuracy, anti-interference and corrosion resistance; at the same time, with the help of fiber optic Bragg grating displacement meters, fiber optic Bragg osmometers, and seismic detectors, it can monitor multiple parameters such as geological deformation, water level, pore water pressure, temperature and vibration in the goaf area, collect data comprehensively, and realize all-round monitoring, ensuring that the entire monitoring and early warning data can assist each other, and at the same time implement automated remote online monitoring and pre-judgment alarms, which can help operators quickly respond to dangerous geological conditions in a timely manner; the geological disaster alarm controls the buzzer on site to sound an alarm, which can realize a warning effect on the surrounding area, thereby achieving a high degree of integration between on-site alarms and pre-judgment alarms. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic diagram of the overall structure provided by an embodiment of the present invention.

[0026] In the figure: 1 is a borehole, 2 is a demodulation device, 3 is a monitoring platform, 4 is a fiber Bragg grating displacement meter, 5 is a fiber Bragg grating piezometer, 6 is a geological disaster alarm, 7 is a seismic detector, 8 is a fiber Bragg grating thermometer, 9 is a solar power supply system, 10 is a buzzer, 11 is a jumper, and 12 is a counterweight. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, all the connection relationships mentioned in the text do not refer to the direct connection of components, but refer to the fact that a better connection structure can be formed by adding or reducing connection accessories according to the specific implementation situation.

[0028] See also Figure 1 As shown, a gypsum mine collapse monitoring system includes a borehole 1, a monitoring sensor, a demodulation device 2, a monitoring platform 3, and a buzzer 10.

[0029] The plurality of boreholes 1 are independently arranged at various monitoring positions in the goaf, and the selection of the monitoring positions is based on the ability to reduce losses; the interval between adjacent boreholes 1 is between 500m and 1000m; the monitoring sensor is arranged in a borehole 1, and the monitoring sensor is mainly used to monitor the conditions at various depths underground in the goaf;

[0030] The demodulation device 2 is arranged in a safe area and corresponds to the borehole 1 one by one. The demodulation device 2 itself has a wireless transmission module and a GPS positioning module, which can transmit the demodulated signal to the monitoring platform 3. In order to make the demodulation device 2 more energy-saving and ensure sufficient power, the demodulation device 2 is connected to the solar power supply system 9; a plurality of the demodulation devices 2 are connected to the monitoring sensor through a jumper 11 and a junction box, that is, a monitoring sensor is installed in a borehole 1 and connected to a demodulation device 2; the demodulation device 2 has a built-in fast tunable laser light source module, which monitors the monitoring sensor by changing the output wavelength of the tunable light source. The central wavelength of the sensor is obtained, and then the physical value of each fiber grating sensor is obtained, and then it is uploaded to the monitoring software of the monitoring platform 3 through remote networking transmission; the monitoring software of the monitoring platform 3 can compare and analyze the data, view data trends, and measure wavelengths; the monitoring software can also make predictions and alarms based on the data trend analysis of each monitoring point, and according to the real-time online data of each monitoring point, it can determine the center point of the impending collapse and the scope of the collapse; the types of prediction alarms include vertical settlement alarms, groundwater level alarms, and ground collapse vibration alarms, and the types of prediction alarms are mainly determined by the type of monitoring sensor signals.

[0031] The monitoring sensor is a Bragg fiber grating (FBG) sensor, which is formed by changing the refractive index of the fiber core to produce a small periodic modulation; when the temperature or stress changes, the fiber produces axial strain, which makes the grating period larger, while the radius of the fiber core and cladding decreases, and the refractive index of the fiber is changed through the photoelastic effect, thereby causing the grating wavelength to shift; the linear relationship between strain and grating wavelength shift is used to calculate the strain of the measured structure; the wavelength demodulation accuracy of FBG reaches 1pm, corresponding to its strain test accuracy of about 1 microstrain, and the temperature demodulation accuracy is 0.1℃; the monitoring sensors include fiber grating displacement meter 4, fiber grating permeability Pressure gauge 5, geological disaster alarm 6, seismic detector 7; several fiber Bragg grating displacement meters 4 are connected in series along the axial direction of the borehole 1 to form a U-shaped loop structure. In order to avoid the entire U-shaped loop structure being unable to monitor data when one fiber Bragg grating displacement meter 4 is damaged, the U-shaped loop structure includes two parallel ones (not shown in the figure); when the two U-shaped loop structures are in normal working state, the two correct each other to ensure the accuracy of the data. After any of the U-shaped loop structures fails, they are used as a backup to ensure the normal data; the fiber Bragg grating displacement meter 4 plus the screw guide method is used to realize long-scale online real-time monitoring of the displacement change of the rock and soil body within a specified length range.

[0032] The fiber Bragg grating piezometer 5 is mainly used to monitor the groundwater level. In order to avoid excessive parameter changes of the fiber Bragg grating piezometer 5 due to temperature differences, the monitoring sensor also includes a fiber Bragg grating thermometer 8 for temperature compensation of the fiber Bragg grating piezometer 5; the fiber Bragg grating thermometer 8 is consistent with the depth of the borehole 1 where the fiber Bragg grating piezometer 5 is located.

[0033] The geological disaster alarm 6 is only affected by the stretching of the strata, and is not affected by external conditions such as temperature and water. The geological disaster alarm 6 transmits the signal to the demodulation device 2, and the demodulation device 2 transmits the signal to the buzzer 10, causing the buzzer 10 to emit a sharp alarm sound, thereby making an on-site alarm; at the same time, in order to distinguish the severity of geological disasters, the geological disaster alarm 6 can be divided into multiple alarm levels, and the buzzer 10 can emit on-site alarms of different sounds or different intensities; usually, there are three alarm levels, which can be customized according to specific geological conditions.

[0034] For the convenience of installation, a counterweight 12 is sunk at the bottom of the borehole 1. The counterweight 12 is usually an iron cylinder, and the outer diameter of the counterweight 12 is adapted to the inner diameter of the borehole 1, that is, the counterweight 12 can sink to the bottom of the borehole 1 without horizontal shaking. The counterweight 12 is fixedly connected to the bottom optical fiber cables of the fiber grating displacement meter 4, the fiber grating osmometer 5, the geological disaster alarm 6, and the seismic detector 7, thereby ensuring that the fiber grating displacement meter 4, the fiber grating osmometer 5, the geological disaster alarm 6, and the seismic detector 7 always remain in a vertical state during the backfilling process of the borehole 1.

[0035] The assembly process of the present invention is as follows: the first step: according to the various monitoring positions pre-determined around the goaf of the gypsum mine, a borehole 1 is drilled at each monitoring position, the depth of the borehole 1 is 1m above the bedrock, and the depth of the borehole 1 is usually 30m; a demodulation device 2 corresponding to the borehole 1 is arranged in a safe area (non-goaf area) near the borehole 1, and a buzzer 10 corresponding to the borehole 1 is arranged near the goaf where the borehole 1 is located (the position where a warning is required);

[0036] Step 2: Select a counterweight block 12 with suitable counterweight and material, and ensure that the counterweight block 12 is compatible with the inner diameter of the borehole 1; connect several fiber Bragg grating displacement meters 4 in series into a U-shaped loop structure, and fix the lowest position of the U-shaped loop structure on the top surface of the counterweight block 12. In order to ensure the monitoring accuracy, two U-shaped loop structures are provided; wrap the fiber Bragg grating osmometer 5 with gauze and fix it to the counterweight block 12, and determine that the sinking position of the fiber Bragg grating osmometer 5 is accurate; fix the seismic detector 7 and the geological disaster alarm 6 to the counterweight block 12, and connect them to the collector; fix the bottom of the fiber Bragg grating where the fiber Bragg grating thermometer 8 is located to the counterweight block 12, and the sinking depth of the fiber Bragg grating thermometer 8 is consistent with the sinking depth of the fiber Bragg grating osmometer 5;

[0037] Step 3: lower the counterweight block 12 equipped with the monitoring sensor to the end surface at the bottom of the borehole 1 and ensure that the counterweight block 12 itself is horizontally stable;

[0038] Step 4: Keep the optical fiber cables where the fiber Bragg grating displacement meter 4, the fiber Bragg grating piezometer 5, the geological disaster alarm 6, the seismic detector 7, and the fiber Bragg grating thermometer 8 are located vertically in a tight state, backfill the fine sand around the gypsum mine into the borehole 1, and ensure that the borehole 1 is backfilled tightly;

[0039] Step 5: Connect the optical grating extending from the top of the monitoring sensor through the borehole 1 to the demodulation device 2 through a jumper 11, and bury the optical grating extending from the borehole 1 on the surface;

[0040] Step 6: electrically connect the demodulation device 2 to the solar power supply system 9; connect the demodulation device 2 to the buzzer 10 via a jumper 11, and bury the jumper 11 on the ground;

[0041] Step 7: Start monitoring and use the effective initial monitoring value as the monitoring benchmark; in subsequent continuous monitoring, use the initial monitoring value as a reference for analysis; the monitoring platform 3 displays the analyzed monitoring attempts, data, etc., and issues a predictive alarm in a timely manner.

[0042] It should be noted that the "up, down, left, right, inside, and outside" in the present invention are defined based on the relative positions of the components in the figure. This is only for the clarity and convenience of describing the technical solution. It should be understood that the use of these directional words does not constitute a limitation on the scope of protection of this application.

[0043] The implementation modes described above are only preferred implementation modes and are not used to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions recorded in the aforementioned implementation modes or to replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A gypsum mine subsidence monitoring system, characterized in that: It includes a borehole, a monitoring sensor, a demodulation device, a monitoring platform, and a buzzer; a plurality of the boreholes are independently arranged at various monitoring positions in the goaf; the monitoring sensor is arranged in a borehole; the demodulation device is arranged in a safe area and corresponds to the boreholes one by one; a plurality of the demodulation devices are connected to the monitoring sensors through jumpers and the monitoring data of each monitoring point is uploaded to the monitoring software of the monitoring platform for comparison and analysis, and an independent prejudgment alarm is issued for each monitoring point; the buzzer is installed at the surface of the monitoring point and is connected to the demodulation device one by one; wherein, The monitoring sensors include fiber Bragg grating displacement meters, fiber Bragg osmometers, geological disaster alarms, and seismic detectors; a number of the fiber Bragg grating displacement meters are connected in series along the borehole axis to form a U-shaped loop structure; a number of the seismic detectors are connected in parallel and are distributed in high and low places in the borehole; the buzzer can issue an on-site alarm based on the signal transmitted from the geological disaster alarm to the demodulation device; A counterweight is sunk at the bottom of the borehole; the counterweight is fixedly connected to the bottom optical fiber cable of the fiber Bragg grating displacement meter, the fiber Bragg grating osmometer, the geological disaster alarm, and the seismic detector; The specific monitoring method of the gypsum mine subsidence monitoring system is as follows: S1: Drill a hole at each pre-determined monitoring position around the goaf of the gypsum mine, with the depth of the hole being 1m above the bedrock; deploy a demodulation device corresponding to the hole in a safe area near the hole, and deploy a buzzer corresponding to the hole near the goaf where the hole is located; S2: Select a counterweight block with appropriate weight and material, and ensure that the counterweight block is compatible with the inner diameter of the borehole; connect several fiber Bragg grating displacement meters in series to form a U-shaped loop structure, and fix the lowest position of the U-shaped loop structure on the top surface of the counterweight block; wrap the fiber Bragg grating piezometer with gauze and fix it to the counterweight block; fix the seismic detector and geological disaster alarm to the counterweight block; S3: Lower the counterweight block equipped with the monitoring sensor to the end surface at the bottom of the borehole and ensure the horizontal stability of the counterweight block itself; S4: Keep the optical fiber cables where the fiber Bragg grating displacement meter, fiber Bragg osmometer, geological disaster alarm, and seismic detector are located vertically and in a tight state, backfill the fine sand around the gypsum mine into the borehole, and ensure that the borehole is backfilled tightly; S5: Connect the optical grating extending out of the borehole at the top of the monitoring sensor to the demodulation device through a jumper, and bury the optical grating extending out of the borehole on the surface; S6: electrically connect the demodulation device to the solar power supply system; connect the demodulation device to the buzzer through a jumper, and bury the jumper on the surface; S7: Start monitoring and use the effective initial monitoring value as the monitoring benchmark; in subsequent continuous monitoring, use the initial monitoring value as a reference for analysis; the monitoring platform will display the analyzed monitoring attempts and data, and issue a predictive alarm in a timely manner.

2. A gypsum mine subsidence monitoring system according to claim 1, characterized in that: The demodulation device is powered by a solar power supply system.

3. A gypsum mine subsidence monitoring system according to claim 1, characterized in that: The U-shaped loop structure includes two parallel connections.

4. A gypsum mine subsidence monitoring system according to claim 1, characterized in that: The monitoring sensor also includes a fiber Bragg grating thermometer for temperature compensation of the fiber Bragg grating piezometer; the fiber Bragg grating thermometer is at the same depth as the borehole where the fiber Bragg grating piezometer is located.

5. A gypsum mine subsidence monitoring system according to claim 1, characterized in that: The demodulation device is provided with a wireless transmission module.

6. A gypsum mine subsidence monitoring system according to claim 1, characterized in that: The prejudgment alarm includes vertical settlement alarm, groundwater level alarm, and ground collapse vibration alarm.

7. A gypsum mine subsidence monitoring system according to claim 1, characterized in that: In step S3, the monitoring sensor includes a fiber grating thermometer; the depth of the borehole where the fiber grating thermometer is located is consistent with the depth of the borehole where the fiber grating piezometer is located; the bottom of the fiber grating where the fiber grating thermometer is located is connected to the counterweight block, and the light grating extending out of the borehole at the top is fused with the demodulation device.

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