Dynamic delineation of spontaneous combustion zones in goaf-side goaf-retaining lanes and coordinated prevention and control technology

Abstract

The present invention discloses a technology for dynamically defining and coordinating the spontaneous combustion areas of coal in goafs along goafs with tunnels, including technology for dynamically defining and coordinating the spontaneous combustion areas of coal in goafs along goafs with tunnels and technology for coordinating the spontaneous combustion of coal in goafs along goafs with tunnels. Combining a two-dimensional monitoring system for spontaneous combustion of coal in goafs and a visualized three-dimensional real-time dynamic deduction, a method for grading the hazard index of spontaneous combustion areas of coal based on the intersection and union of composite characteristic indicators and extreme values ​​is proposed to predict the three-dimensional evolution trend of catastrophic spontaneous combustion areas and implement differentiated governance measures. Multiple air leakage prevention processes on the walls of goafs with tunnels and blocking-idling-isolating-cold-wrapping fire prevention and extinguishing technologies are used to coordinately prevent and control spontaneous combustion of coal in goafs along goafs with tunnels. The multifunctional pulping and spraying vehicle for mining consists of a reverse hedging and anti-sedimentation mud mixing box, an intermittent spiral wall scraping mud conveying box, a mechanical arm spraying device and a telescopic camera device. It can prepare and spray modified fly ash slurry to efficiently block cracks on the walls of goafs with tunnels.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine safety, and in particular to a technology for preventing and controlling coal spontaneous combustion in goaf areas along goaf-retained lanes in underground coal mines. Background Art

[0002] Green mining technologies represented by gob-side tunneling technology have become the main development trend of the coal industry. However, due to air leakage in the gob-side tunneling structure, more fresh air flows into the goaf, which increases the risk of spontaneous combustion of coal in the goaf. At present, most of the tests on gob-side spontaneous combustion disaster-causing parameters are based on stable state simulation and field measurements. There is a lack of prediction of the evolution trend of coal spontaneous combustion areas during the dynamic advancement of the goaf, and there is also a lack of on-site test device layout methods targeting gob-side tunneling. The division of coal spontaneous combustion areas in goafs generally uses indicators such as leakage wind speed, oxygen concentration, and temperature rise, but lacks coupled research and judgment on the disaster-causing range of different indicators.

[0003] The present invention is based on the goaf of goafs along the goaf, and combines the on-site two-dimensional measurement of temperature / gas / air leakage and other coal spontaneous combustion characteristic indicators with the three-dimensional real-time dynamic deduction of the coal spontaneous combustion area visualization, to achieve a three-dimensional perspective of the disaster area of ​​the goafs along the goafs. Referring to the temporal and spatial evolution trend of temperature / gas / air leakage in the goafs along the goafs, a method for grading the hazard index of the coal spontaneous combustion area is constructed, and then differentiated management is carried out for different levels of dangerous areas. At the same time, a multi-air leakage prevention process for the wall of goafs along the goafs is proposed to reduce the air leakage of goafs along the goafs, and the blocking-inert-isolation-cooling-wrapping fire prevention and extinguishing technology is used to deal with the prevention and control of spontaneous combustion of goafs of different dangerous levels. Summary of the invention

[0004] The purpose of the present invention is to provide a step-by-step dynamic delineation technology for the coal spontaneous combustion area in the goaf along the goaf and a coordinated prevention and control technology for the coal spontaneous combustion in the goaf along the goaf, so as to overcome the problem of difficulty in preventing and controlling the coal spontaneous combustion in the goaf along the goaf.

[0005] To achieve the above-mentioned purpose, the present invention provides a technology for dynamic delineation of spontaneous combustion areas of coal in goafs along goafs with lanes and coordinated prevention and control, including technology for dynamic delineation of spontaneous combustion areas of coal in goafs along goafs with lanes and coordinated prevention and control of spontaneous combustion of coal in goafs along goafs with lanes. The technology for dynamic delineation of spontaneous combustion areas of coal in goafs along goafs with lanes includes a visualized three-dimensional real-time dynamic simulation of spontaneous combustion areas of coal, a two-dimensional monitoring system design for spontaneous combustion of coal in goafs, and a tiered classification of the hazard index of spontaneous combustion areas of coal. The coordinated prevention and control technology for spontaneous combustion of coal in goafs along goafs with lanes includes a multiple air leakage prevention process on the wall of goafs with lanes and a blocking-inert-isolation-cooling-wrapping fire prevention and extinguishing technology.

[0006] Furthermore, the three-dimensional real-time dynamic simulation of the coal spontaneous combustion area is visualized, that is, based on the full-scale physical model of the goaf area along the goaf, the pore distribution function is built through code programming, and the dynamic mining process is presented using dynamic grid technology to study the changes in the evaluation indicators of coal spontaneous combustion in the goaf area along the goaf. The specific steps are to build a full-scale physical model through the physical parameters of the working face, tunnel, and goaf of the underground mine; determine the porosity distribution function of the goaf and complete the porosity model construction based on the programming software; determine the oxygen consumption rate / characteristic gas release rate / heat release intensity of the coal sample through a programmed temperature rise experiment; use fluid dynamics visualization simulation software as a platform and dynamic grid technology as a carrier to conduct multi-field coupling numerical simulation of the goaf area along the goaf under dynamic mining conditions, and obtain the correlation between the coal spontaneous combustion evaluation indicators such as temperature rise gradient / air leakage speed / characteristic gas concentration and the working face advancement speed and tunnel ventilation volume, obtain the optimal advancement speed of the working face, and reduce the risk of spontaneous combustion in the goaf area along the goaf. The simulation three-dimensional deduction results are mutually verified with the two-dimensional on-site measurements, and the three-dimensional spatial migration trend of the spontaneous combustion area of ​​the coal in the goaf is predicted in advance, realizing a three-dimensional perspective of the disaster area in the goaf along the goaf.

[0007] Furthermore, the two-dimensional monitoring system for spontaneous combustion of coal in goaf is designed to arrange temperature / gas / leakage measurement equipment according to the characteristics of air leakage in goaf along goaf-retained lanes, and to design an elastic optical fiber protection device to prevent the measurement equipment from being damaged by falling rocks in goaf. The temperature test adopts distributed optical fiber temperature measurement, and the optical fiber is arranged in a U shape as a whole. The one entering from air intake lane I is a positive U shape, and the one entering from air intake lane II is a reverse U shape. Two groups of U-shaped temperature measurement optical fibers are arranged in an interlaced manner to achieve full-range monitoring of goaf temperature, and each group contains two temperature measurement optical fibers. Focus on the spontaneous combustion area of ​​coal along the goaf-retained lane side, and add an L-shaped temperature measurement optical fiber with the range of the spontaneous combustion area predicted by the three-dimensional real-time dynamic deduction of the coal spontaneous combustion area as the center. The gas test adopts beam tube gas measurement, which is arranged on both sides of the goaf along the goaf-retained lane, and has both infrared real-time analysis and chromatographic comprehensive analysis. The air leakage rate test is centered on tracer gas. A certain amount of tracer gas is released once from the junction of air intake tunnel I and the edge of the goaf. The side bundle pipes along the goaf-retaining tunnel receive the tracer gas to determine whether there is air leakage in the goaf along the goaf-retaining tunnel and the direction and speed of the leakage.

[0008] Furthermore, the elastic optical fiber protection device includes a transparent retractable outer shell, a transparent retractable inner wall, a screw-on base, an elastic ball, a plastic spring, and a retractable sleeve; the transparent retractable outer shell and the transparent retractable inner wall are made of retractable materials, which can be compressed and rebounded with stress changes and have plasticity; the screw-on base is embedded between the transparent retractable outer shell and the transparent retractable inner wall, and when subjected to stress, the screw-on base is successively pushed and rotated along the hollow circle around the center of the circle to disperse the stress concentration point; the screw-on base is connected to the elastic ball through a spinning caliper, and the elastic ball can spin in the horizontal direction, and the force acting on the ball is dispersed 360° circumferentially; at the same time, the elastic ball is connected to the plastic spring, and the plastic spring is wrapped with a retractable sleeve, so that the spring can be retracted up and down in the retractable sleeve along the centripetal direction, and there are a total of six groups distributed in a circular array in sequence, and the six groups interact with each other to maximize the buffering effect and prevent the optical fiber from being damaged by coal.

[0009] Furthermore, the coal spontaneous combustion area hazard index ladder is divided into coal spontaneous combustion areas centered on O2 concentration, air leakage speed, temperature rise gradient, and CO concentration. The union of O2 concentration (C1-C2), air leakage speed (C3-C4), temperature rise gradient (>C5), and CO concentration (>C6) in the coal spontaneous combustion hazard interval is used as the potential coal spontaneous combustion area, and then the potential coal spontaneous combustion area is accurately classified. When the four characteristic indicators are in the danger interval at the same time, the potential coal spontaneous combustion area is an extremely high-risk coal spontaneous combustion area. In addition, the division of the danger interval of the temperature rise gradient and CO concentration is unidirectional, and there are maximum over-limit values ​​within the measurement conditions. The maximum over-limit value indicates that the probability of coal spontaneous combustion is high. Therefore, with the maximum over-limit temperature rise gradient and CO concentration position as the core, radiating a certain distance around, this interval is also defined as an extremely high-risk coal spontaneous combustion area. When three of the characteristic indicators are in the danger interval at the same time, the potential coal spontaneous combustion area is a high-risk coal spontaneous combustion area. When two of the characteristic indicators are in the danger zone, the potential coal spontaneous combustion area is a medium-risk coal spontaneous combustion area. When one of the characteristic indicators is in the danger zone, the potential coal spontaneous combustion area is a low-risk coal spontaneous combustion area. The experiment determines the critical temperature of coal spontaneous combustion and the corresponding CO concentration of the mine coal, and determines the core spontaneous combustion disaster area where the coal sample begins to spontaneously heat up.

[0010] Furthermore, the multiple air leakage prevention processes for the wall of the gob-retained tunnel are divided into plugging before and after support. Before support, a multifunctional mining slurry spraying vehicle is used to spray inorganic polymer fly ash colloidal mud on the coal in the gob area of ​​the gob-retained tunnel side, so as to inhibit the continued oxidation of the coal from two angles: encapsulating the initially oxidized coal and lowering the coal temperature. When the support structure of the gob-retained tunnel is formed, the inorganic polymer fly ash colloidal mud is plugged by pushing and spraying to quickly reduce the air leakage. Then, a thickened fireproof wind duct curtain is hung, and high-viscosity and quick-setting fly ash mud is sprayed at the connection between the wind duct curtain and the top / bottom of the tunnel.

[0011] Furthermore, the multifunctional pulping and spraying vehicle for mining includes two functions: preparation and spraying of modified fly ash slurry. Modified slurry is divided into inorganic polymer fly ash colloidal slurry and high-viscosity quick-setting fly ash slurry. The multifunctional pulping and spraying vehicle for mining includes a vehicle body, a reverse hedging anti-sedimentation slurry mixing box, an intermittent spiral scraping slurry conveying box, a mechanical arm spraying device and a telescopic camera device. The mixing box is located at the upper part of the conveying box, and there are two one-way solenoid valve feeding ports at the bottom of the mixing box, which can transport the fly ash slurry from the mixing box to the conveying box; an auxiliary agent addition port is provided on the conveying box, which is connected to the flow valve, and a suspending agent, a thickener, etc. can be added to the fly ash slurry. The telescopic camera device consists of a base, a telescopic rod, an explosion-proof camera, a rotating motor, and a cleaning brush; the base can rotate to observe the tunnels in different parts according to the actual situation to determine whether there are coal seam cracks. The robotic arm spraying device consists of a base, a rotating shaft, a robotic arm, a hydraulic device, and a spray gun; the spraying device can rotate with the rotating shaft, and the large arm can be extended and retracted, and can also be pitched and lowered. The two cooperate with each other to meet the needs of multi-angle spraying, solving the inflexibility of traditional tunnel spraying.

[0012] Furthermore, the interior of the reverse-hedging anti-sedimentation mud mixing box is a combination structure of a cuboid and a chamfered platform. The top feed port is installed on the upper part of the mixing box, including a V-shaped feed funnel, a gravity opening, a dustproof shell, an arched distribution rack and a pad. Fly ash is poured from the top of the V-shaped feed funnel and falls into the mixing box from the evenly distributed openings of the arched distribution rack, and most of the dust is confined to the dustproof shell. The internal mixing structure includes an annular high-pressure water supply hole, an outward-expanding folding-blade multi-layer agitator, a porous internally-thrown speed reducer, a central inclined guide plate, etc. The two sides rotate in opposite directions to the central folding-blade multi-layer agitator to improve the uniformity of mud mixing; a porous internally-thrown speed reducer is set on the upper end of the chamfered platform to slow down the mud sinking speed and provide sufficient mixing time; an annular high-pressure water supply hole is set in the upper part of the mixing box, and is arranged at equal distances and equal flow rates.

[0013] Furthermore, the intermittent spiral scraping mud conveying box includes an outer square inner circle conveying box body, a fly ash mud inlet, an additive inlet, an intermittent spiral, a mixing and stirring rod, a main rotating shaft, a metal frame, a flexible rubber scraper, an explosion-proof motor and a mud outlet. The inside of the conveying box, the intermittent spiral, the mixing and stirring rod, the main rotating shaft and the metal frame surface are all coated with a nano coating. The intermittent spiral, the mixing and stirring rod, the metal frame and the flexible rubber scraper rotate with the rotation direction of the main rotating shaft. There are two intermittent openings inside the intermittent spiral, and the slurry part pushed forward flows out from the intermittent openings and mixes with the slurry behind to generate a certain shear force, thereby improving the mixing between different materials. The mixing and stirring rod and the intermittent spiral are arranged in an alternating manner to improve the mud mixing efficiency. The flexible rubber scraper is connected to the outside of the metal frame and is tangent to the inner surface of the conveying box. In the process of conveying the modified fly ash slurry, the surface material on the inner wall of the conveying box is scraped off to prevent the additive with a small content from adhering to the inner wall of the conveying box, which cannot fully improve the performance of the fly ash slurry.

[0014] Furthermore, the blocking-inertization-isolation-cooling-wrapping fire prevention and extinguishing technology includes physical shielding to reduce air leakage, nitrogen inertization asphyxiation, injection of inorganic polymer fly ash colloidal slurry around the fire area to isolate the spread, and injection of high-water material into the fire area to quickly cool down and wrap the coal body. The specific steps are to use different isolation and wind blocking devices for the working face, wall surface, and the junction of the air intake tunnel and the goaf to reduce the air leakage rate into the goaf; according to the different danger levels of coal spontaneous combustion areas, use buried pipes, drilling and other methods to intelligently inject nitrogen into the goaf, and the danger level of the coal spontaneous combustion area will be increased, and the scale of nitrogen injection will be increased; when the danger level of the coal spontaneous combustion area reaches extremely high danger, in addition to expanding the scale of nitrogen injection, additional inorganic polymer fly ash colloidal mud will be injected in and around the extremely high-risk areas; identify the core spontaneous combustion disaster area with critical temperature of coal spontaneous combustion and corresponding CO concentration in the goaf along the goaf, inject inorganic polymer fly ash colloidal mud around the disaster area to isolate the spread, and inject high-water material into the core spontaneous combustion disaster area to quickly cool down and wrap the coal body. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a technical framework diagram of the step-by-step dynamic delineation and coordinated prevention of spontaneous combustion areas of coal in goafs along goaf-retained lanes of the present invention;

[0016] Figure 2 This is a layout diagram of the two-dimensional monitoring system for spontaneous combustion of coal in goaf areas of the present invention;

[0017] Figure 3 This is a structural diagram of the elastic optical fiber protection device of the present invention;

[0018] Figure 4 This is a flow chart of the tiered classification of the coal spontaneous combustion area hazard index of the present invention;

[0019] Figure 5 This is a process diagram for preventing multiple air leakage on the wall surface of the gob-side tunnel retaining system of the present invention;

[0020] Figure 6 This is a structural diagram of the multifunctional pulping and spraying vehicle for mining of the present invention;

[0021] Figure 7 This is a structural diagram of the reverse hedging and anti-sedimentation slurry mixing box of the present invention;

[0022] Figure 8 This is a structural diagram of the annular water delivery device of the present invention;

[0023] Fig. 9 This is a structural diagram of the intermittent spiral wall scraping mud conveying box of the present invention.

[0024] Specific implementation process

[0025] Figure 1The framework diagram of the technology for dynamic delineation of spontaneous combustion areas of coal in goafs along goafs and tunnels and coordinated prevention and control of the present invention mainly includes the technology for dynamic delineation of spontaneous combustion areas of coal in goafs along goafs and tunnels and the technology for coordinated prevention and control of spontaneous combustion of coal in goafs along goafs and tunnels.

[0026] The technology of dynamic delineation of the spontaneous combustion area of ​​coal in goafs along the goaf includes the three-dimensional dynamic deduction of the spontaneous combustion area, the design of the two-dimensional monitoring system of spontaneous combustion in goafs, and the gradation of the hazard index of spontaneous combustion areas. The three-dimensional dynamic deduction of the spontaneous combustion area of ​​coal is based on the full-scale physical model of the goafs along the goafs, the pore distribution function is built through code programming, the dynamic mining process is presented by the dynamic grid technology, and the changes of the evaluation indicators of spontaneous combustion in goafs along the goafs are studied. The specific steps are to build a full-scale physical model through the physical parameters of the working face, tunnel and goaf of the underground mine; determine the porosity distribution function of the goaf and complete the porosity model construction based on the programming software; determine the oxygen consumption rate / characteristic gas release rate / heat release intensity of the coal sample through the programmed temperature rise experiment; use the fluid dynamics visualization simulation software as the platform and the dynamic grid technology as the carrier to carry out the multi-field coupling numerical simulation of the goaf along the goaf under dynamic mining conditions, and obtain the correlation between the coal spontaneous combustion evaluation indicators such as temperature rise gradient / leakage speed / characteristic gas concentration and the working face advancement speed and tunnel ventilation volume, so as to obtain the optimal advancement speed of the working face and reduce the risk of spontaneous combustion in the goaf along the goaf. The two-dimensional monitoring system for coal spontaneous combustion in the goaf is designed to arrange temperature / gas / leakage measurement equipment according to the leakage characteristics of the goaf along the goaf, and design an elastic optical fiber protection device to prevent the measurement equipment from being damaged by falling rocks in the goaf. The hierarchical division of the coal spontaneous combustion area hazard index is proposed, and the coal spontaneous combustion areas of different hazard levels are divided by the intersection and union of composite characteristic indicators, the maximum CO concentration and the temperature rise gradient. The visualized three-dimensional real-time dynamic simulation of the coal spontaneous combustion area is verified with the on-site two-dimensional measurement, which can predict the three-dimensional spatial migration trend of the coal spontaneous combustion area in the goaf in advance, realize the three-dimensional perspective of the disaster area in the goaf along the goaf, provide a reference for the design of the mining operation process, and reduce the problems of long actual measurement time and heavy workload.

[0027] The coordinated prevention and control technology of coal spontaneous combustion in goafs along goafs includes multiple air leakage prevention processes on goaf-retained goaf walls and blocking-inert-isolation-cooling-wrapping fire prevention and extinguishing technologies. The multiple air leakage prevention processes on goaf-retained goaf walls are to spray fire-proof and wind-blocking modified fly ash slurry and wind tube curtains in sequence inside and outside the filling support structure. The blocking-inert-isolation-cooling-wrapping fire prevention and extinguishing technologies include physical shielding to reduce air leakage, nitrogen inert asphyxiation, injection of inorganic polymer fly ash colloidal slurry around the fire area to isolate the spread, and injection of high-water materials in the fire area to quickly cool and wrap the coal body. The specific steps are to use different isolation and wind-blocking devices for the working face, wall surface, and the junction of the air intake tunnel and the edge of the goaf to reduce the air leakage rate into the goaf; set up a gangue bag wall at the junction of the air intake tunnel and the edge of the goaf, spray the wall surface with anti-leakage materials, and hang two wind curtains at the upper and lower ends of the working face, or use the hanging mesh spraying method to further reduce the wind flow into the goaf; taking measures to reduce air leakage in the goaf along the goaf in advance will help to form the effect of nitrogen accumulation to inertate the coal left in the high-level goaf, and improve the ability to prevent and control coal spontaneous combustion in the goaf along the goaf. According to the different dangerous levels of coal spontaneous combustion areas, the goaf is intelligently injected with nitrogen by burying pipes, drilling holes, etc. to achieve the effect of inert suffocation. The dangerous level of the coal spontaneous combustion area is increased, and the scale of nitrogen injection is increased. When the risk level of coal spontaneous combustion area reaches extremely high risk, in addition to expanding the scale of nitrogen injection, additional inorganic polymer fly ash colloidal mud is injected in extremely high risk areas and surrounding areas; the amount of nitrogen injection / grouting is intelligently controlled with the dynamic changes of the level of coal spontaneous combustion area. If the core spontaneous combustion disaster area with critical temperature of coal spontaneous combustion and corresponding CO concentration is identified in the goaf of goaf-retaining lanes, inorganic polymer fly ash colloidal mud is injected around the spontaneous combustion disaster area to isolate the spread, and high water material is injected into the quasi-spontaneous combustion disaster area to quickly cool down and wrap the coal body. By proposing the anti-leakage measures of goaf-retaining lanes combined with modified fly ash mud and wind tube curtain, and applying the blocking / inert fire prevention and isolation / cooling / wrapping fire extinguishing goaf area management technology, the risk of coal spontaneous combustion in goaf-retaining lanes and goafs has been effectively prevented to a certain extent; the amount of nitrogen / fly ash slurry injection is intelligently controlled according to the different risk levels of coal spontaneous combustion areas to reduce the loss of nitrogen / fly ash slurry.

[0028] Figure 2This is the layout diagram of the two-dimensional monitoring system for spontaneous combustion of coal in goafs of the present invention. The two-dimensional monitoring system for spontaneous combustion of coal mainly includes temperature testing, gas testing and air leakage velocity testing. The temperature test adopts distributed optical fiber temperature measurement. The optical fiber has the characteristics of small size, long measurement distance, easy bending, etc. It is convenient to arrange in the goaf and the measurement result is highly accurate. The distributed optical fiber temperature measurement adopts a U-shaped layout as a whole. The one entering from the air intake tunnel I is a positive U-shape, and the one entering from the air intake tunnel II is a reverse U-shape. The two groups of U-shaped temperature measurement optical fibers are staggered to achieve full-range monitoring of the temperature of the goaf. At the same time, each group contains two temperature measurement optical fibers, which are designed as one for use and one for backup to prevent the loss of monitoring data due to a single failure. The design of the goaf-side lane increases the air leakage on one side of the goaf, changes the distribution structure of the coal spontaneous combustion area, and expands the risk of coal spontaneous combustion in the goaf. Therefore, it is necessary to focus on the coal spontaneous combustion area on the side of the goaf-side lane. With the range of the coal spontaneous combustion area predicted by the three-dimensional real-time dynamic simulation of the coal spontaneous combustion area as the center, an L-shaped temperature measurement optical fiber is added to focus on the coal spontaneous combustion area on the side of the gob retention. The gas test uses a beam tube gas measurement, which is arranged on both sides of the gob retention area along the gob retention area, and has two detection methods: infrared real-time analysis and chromatographic comprehensive analysis. Infrared analysis is used to monitor the concentration of key gases such as O2, CO, and CO2 in the low-temperature oxidation stage of coal spontaneous combustion in real time, and chromatographic analysis focuses on measuring the concentration of gases such as C2H4, C2H6, and C2H2 in the high-temperature stage of coal spontaneous combustion. The air leakage velocity test is centered on the tracer gas, and a certain amount of tracer gas is released once from the junction of the air inlet tunnel I and the edge of the gob retention area. The tracer gas is received by the beam tube on the side of the gob retention area, and the time when the tracer gas reaches the peak at each point is determined. The minimum velocity of the air leakage channel at each collection point is calculated, and then the presence of air leakage in the gob retention area, as well as the direction and velocity of air leakage are determined.

[0029] Figure 3 The elastic optical fiber protection device of the present invention is a structural diagram. The elastic optical fiber protection device includes a transparent retractable outer shell, a transparent retractable inner wall, a screw base, an elastic ball, a plastic spring, and a retractable sleeve; the transparent retractable outer shell and the transparent retractable inner wall are made of retractable material. When the optical fiber is hit by coal, it is subjected to an external force F R The outer shell and inner wall of the transparent retractable shell can be compressed and rebounded with stress changes, and have plasticity; the screw-on base is embedded between the transparent retractable outer shell and the transparent retractable inner wall. R When in action, the rotating base can be pushed and rotated in a circular shape along the hollow center, continuously shifting the pressure application point and releasing the pressure F in the tangential direction to a certain extent. t ; The elastic ball is connected to the rotating base through the spinning caliper, and the stress F released in the tangential direction t Make the elastic balls collide with each other and spin horizontally. The tangential force F acting on the balls t Excite the elastic ball to disperse stress F in all directions 360° c, when colliding, the self-rotation and revolution can interact with each other, minimizing stress concentration; the elastic ball is connected to the plastic spring, and the plastic spring is wrapped with a retractable sleeve. The spring is retracted up and down in the retractable sleeve along the centripetal direction, which can avoid the movement of the plastic spring in other directions and ensure the buffering effect of the centripetal direction on the optical fiber; the six groups of elastic balls and plastic springs are distributed in a circular array in sequence, and the six groups interact with each other, and the external force F R The axial pressure F n Excite spring reverse force F r The upward recoil improves the buffering effect to a certain extent and prevents the optical fiber from being damaged by the coal.

[0030] Figure 4 This is a flow chart for the hierarchical division of the coal spontaneous combustion area hazard index of the present invention. The characteristic indicators of O2 concentration, air leakage rate, temperature rise gradient, and CO concentration are preferably used as the core indicators for the division of coal spontaneous combustion areas. Among them, the O2 concentration in the coal spontaneous combustion hazard zone is C1-C2, the air leakage rate is C3-C4, the temperature rise gradient is>C5, and the CO concentration is>C6. The numerical values ​​of C1, C2, C3, C4, C5, and C6 are selected with reference to existing research and adjusted according to the coal properties / geological conditions. Write the historical cycle series of O2 concentration / air leakage rate / temperature rise gradient / CO concentration under different mining conditions to prevent false alarms due to sudden changes in mining conditions. Obtain the range of O2 concentration, air leakage rate, temperature rise gradient, and CO concentration in the goaf along the goaf that is in the coal spontaneous combustion hazard zone, and take the union of the coal spontaneous combustion hazard zone ranges as the potential coal spontaneous combustion area A, A=A O2 ∪A 漏风 ∪A 温升 ∪A CO , and then accurately classify the potential coal spontaneous combustion areas. When the four characteristic indicators of O2 concentration / leakage velocity / temperature rise gradient / CO concentration are simultaneously in the coal spontaneous combustion danger zone, the potential coal spontaneous combustion area is an extremely high-risk coal spontaneous combustion area, that is, A 极高危 =A O2 ∩A 漏风 ∩A 温升 ∩A CO . And the division of the dangerous interval for temperature rise gradient and CO concentration is one-way. There is a maximum over-limit value within the measurement conditions. The maximum over-limit value indicates that the probability of coal spontaneous combustion is relatively high. Therefore, with the maximum over-limit temperature rise gradient and CO concentration position as the core, radiating a certain distance around, this interval is also defined as the extremely high-risk coal spontaneous combustion area. When three of the characteristic indicators of O2 concentration / leakage speed / temperature rise gradient / CO concentration are in the coal spontaneous combustion danger zone at the same time, the potential coal spontaneous combustion area is a high-risk coal spontaneous combustion area, that is, A 高危 =A O2 ∩A 漏风 ∩A 温升 / A 漏风 ∩A 温升 ∩ACO / A O2 ∩A 温升 ∩A CO When two of the characteristic indicators of O2 concentration / leakage velocity / temperature rise gradient / CO concentration are in the coal spontaneous combustion danger zone, the potential coal spontaneous combustion area is the medium-risk coal spontaneous combustion area, that is, A 中危 =A O2 ∩A 漏风 / A O2 ∩A 温升 / A O2 ∩A CO / A 漏风 ∩A 温升 / A 漏风 ∩A CO / A 温升 ∩A CO When one of the characteristic indicators of O2 concentration / leakage velocity / temperature rise gradient / CO concentration is in the coal spontaneous combustion danger zone, the potential coal spontaneous combustion area is a low-risk coal spontaneous combustion area, that is, A 低危 =A O2 / A 漏风 / A 温升 / A CO The experiment determines the critical temperature of spontaneous combustion of coal in the mine and the corresponding CO concentration, and determines the core spontaneous combustion disaster area where the coal sample begins to spontaneously heat up.

[0031] Figure 5 This is a process diagram for preventing multiple air leakage on the wall of gob-side tunnels of the present invention. The process for preventing multiple air leakage on the wall of gob-side tunnels is divided into plugging before and after support; before support, inorganic polymer fly ash colloidal mud is used to plug the coal in the gob area on the side of the gob-side tunnel; after support, inorganic polymer fly ash colloidal mud is sprayed on the outer surface of the support structure in sequence, thickened fireproof air duct curtains are hung, and high-viscosity and quick-setting fly ash mud is sprayed at the connection between the air duct curtains and the top / bottom of the tunnel. The specific implementation steps are:

[0032] (1) Before the formation of the support structure for the gob retaining tunnel, the residual coal in the gob showed initial signs of oxidation when in contact with air. Inorganic polymer fly ash colloidal mud was used to seal the residual coal in the gob retaining tunnel side, which inhibited the further oxidation of the coal from two perspectives: encapsulating the initially oxidized coal and lowering the coal temperature.

[0033] (2) When the supporting structure of the gob-retained tunnel is formed, inorganic polymer fly ash colloidal mud is used for plugging by pushing and spraying to quickly reduce air leakage. At the same time, the key areas of the support structure (gaps at the joints of the filling materials, gaps at the joints between the filling materials and the top / bottom plates of the tunnel, etc.) are plugged at fixed points for secondary plugging to flexibly fill and plug dead corners.

[0034] (3) The gob-side tunnel is advanced forward by M m. In the 0-M m stage, the first layer of inorganic polymer fly ash colloidal mud is completely solidified. The stress change in the tunnel may cause cracks in the first layer of mud. To prevent air leakage from the cracks, the cracks are quickly sealed with mud and thickened fireproof air duct curtains are hung. The air duct curtain is fixed with expansion bolts. The top is connected to the top of the tunnel and sealed with U-shaped steel. The bottom is connected to the bottom of the tunnel and covered with coal gangue. The upper and lower edges of the air duct curtain extend 0.5m beyond the support structure. After the air duct curtain is sealed, high-viscosity and fast-setting fly ash mud is sprayed on the upper and lower connections and the middle fixed positions to prevent cracks and air leakage at the contact position due to long time.

[0035] (4) Repeat the above steps every time the tunnel advances M m. Through the multiple air leakage prevention technology on the wall of the goaf-retained roadway, the air leakage in the goaf area can be effectively reduced, and the probability of spontaneous combustion of coal in the goaf area of ​​the goaf-retained roadway can be reduced.

[0036] The inorganic polymer fly ash colloidal mud is composed of fly ash slurry, suspending agent, expansion agent and inorganic polymer colloid. The water-cement ratio of fly ash slurry is between 2:1-3:1, the suspending agent is added at 0.05%-0.10%, and the inorganic polymer colloid is added at 0.05%-0.10%. The fly ash slurry plugging can cover the surface of the coal body, isolate the coal from oxygen, and play a good plugging effect. At the same time, the use of fly ash slurry can realize the reuse of industrial waste slag, which has good environmental and economic value; the expansion agent can compensate for the shrinkage and improve the heat cracking resistance of coal under spontaneous combustion baking. The addition of inorganic polymer colloid can effectively improve the water retention of the mud, keep it in a moist state for a long time, and reduce the possibility of cracking; at the same time, after the temperature of the goaf rises, the colloidal water evaporates, taking away a lot of heat, playing a cooling role, and then inhibiting the development of coal spontaneous combustion process. High-viscosity and quick-setting fly ash slurry is a mixture of fly ash slurry and a small amount of thickener and quick-setting agent. It can solidify and adhere quickly and has good sealing performance.

[0037] Figure 6The structure diagram of the multifunctional pulping and spraying vehicle for mining of the present invention. The multifunctional pulping and spraying vehicle for mining includes two functions: preparation and spraying of modified fly ash slurry. The modified slurry is divided into inorganic polymer fly ash colloidal slurry and high-viscosity quick-setting fly ash slurry. The multifunctional pulping and spraying vehicle for mining includes a vehicle body, a reverse hedging anti-sedimentation slurry mixing box, an intermittent spiral scraping mud conveying box, a mechanical arm spraying device and a telescopic camera device. The mixing box is located at the upper part of the conveying box, and there are two one-way solenoid valve feed ports at the bottom of the mixing box, which can transport the fly ash slurry from the mixing box to the conveying box; an auxiliary agent addition port is provided on the conveying box, which is connected to the flow valve, and a suspending agent, a thickener, etc. can be added to the fly ash slurry. The telescopic camera device is composed of a base, a telescopic rod, an explosion-proof camera, a rotating motor, and a cleaning brush; the base can rotate to observe the tunnels in different parts according to the actual situation to determine whether there are cracks in the blocked area. The mechanical arm spraying device consists of a base, a rotating shaft, a mechanical arm, a hydraulic device, and a spray gun; the spraying device can rotate with the rotating shaft, the arm can be extended and retracted, and can be pitched at the same time. The two cooperate with each other to spray at multiple angles, solving the inflexibility problem of traditional spraying. The specific implementation steps of the multi-functional pulping spraying vehicle for mining are:

[0038] (1) Fly ash is added through the opening above the reverse hedging anti-sedimentation slurry mixing box. The water pipe injects an appropriate amount of water into the mixing box, and the explosion-proof motor is started to stir and mix to form fly ash slurry. When no other auxiliary agents are needed, the fly ash slurry can be directly discharged from the side discharge port of the mixing box.

[0039] (2) After a uniform fly ash slurry is formed in the mixing box, the solenoid valve at the bottom of the mixing box is opened to transport the uniformly mixed fly ash slurry to two conveying boxes for conveying and further stirring.

[0040] (3) Add suspending agent, expanding agent and inorganic polymer colloid into one of the conveying boxes through the auxiliary agent addition port to prepare inorganic polymer fly ash colloidal mud; add a small amount of thickener and accelerating agent into the other conveying box to prepare high-viscosity and fast-setting fly ash mud; after the auxiliary agent and fly ash mud are evenly mixed, they are discharged through the side discharge port.

[0041] (4) Under the action of high-pressure wind, the mud has a certain speed; the slurry enters the mechanical arm spraying device to achieve all-round and multi-angle tunnel spraying.

[0042] The multifunctional slurry spraying vehicle for mining can prepare at least two slurries to meet the processing requirements of different working conditions; the superposition of the mixing box and the conveying box can realize multiple stirring, and the slurry composition is more uniform; after the slurry is prepared, the robotic arm spraying device is directly used for spraying, which eliminates the step of transporting the slurry to the sprayer, and can quickly carry out tunnel spraying, reducing operating costs and improving operating quality.

[0043] Figure 7 This is a structural diagram of the reverse-hedging anti-sedimentation slurry mixing box of the present invention. The mixing box includes a top feed port and an internal material mixing and stirring device. The top feed port is installed on the upper part of the mixing box, and includes a V-shaped feed funnel, a gravity opening, a dustproof shell, an arched material distribution frame and a pad. Fly ash is poured from the top of the V-shaped feed funnel. When a certain gravity is reached, the gravity opening opens, and the fly ash enters the dustproof shell. Under the action of its own weight, it disperses to both sides along the arched material distribution frame and falls into the mixing box from the evenly distributed openings of the arched material distribution frame. Most of the floating fly ash during the feeding process is confined to the dustproof shell. Pads are arranged on the edges of the last opening position on both sides of the arched material distribution frame to prevent the fly ash from accumulating in a dead corner on the distribution frame. The opening size of the arched material distribution frame is much larger than the size of the fly ash and will not be blocked; when the feeding stops, the gravity opening closes automatically.

[0044] The internal material mixing and stirring device includes a folding blade multilayer agitator, a porous inner throw speed brake, a central inclined guide plate, and a chamfered platform base. The folding blade multilayer agitator is divided into three parts: left, middle, and right. The folds gradually expand outward from the central rotating axis to both sides. The folding blade multilayer agitators on the left and right sides are exactly the same, and the bottom ends at the upper part of the porous inner throw speed brake. The middle folding blade multilayer agitator runs through the vertical direction of the mixing box. The center of the upper area of ​​the porous inner throw speed brake and the folds of the folding blade multilayer agitators on the left and right sides are arranged alternately. The folds in the lower area of ​​the porous inner throw speed brake gradually shorten with the change of the trapezoidal base. The folding blade multilayer agitators on the left and right sides rotate clockwise, and the middle folding blade multilayer agitator rotates counterclockwise. The fly ash slurry is evenly mixed under the rotating driving force in different directions. In order to prevent the fly ash and water from sliding down rapidly due to their own weight, resulting in uneven mixing, a porous inner throw speed brake is proposed, and a plate-shaped obstacle is set at the upper end of the bottom chamfered platform. The obstacle has parabolic holes inside, which can effectively slow down the sinking speed of the slurry and provide sufficient mixing time. The chamfered platform base is used to fully transport the slurry from the mixing box to the conveying box to prevent the slurry from remaining at the bottom of the mixing box. The central inclined guide plate is used to reduce the slurry sinking speed on the one hand, and to guide the slurry to the center of the rotating device on the other hand to improve the uniform mixing performance.

[0045] Figure 8 This is a structural diagram of the annular water delivery device of the present invention. The annular water delivery device is installed in the upper part of the mixing box, and water is fed in from one side. The water inlet pipe is provided with a flow valve, which can be opened and closed at any time. Water delivery holes are evenly and equidistantly distributed on the annular pipe. The water inside the pipe is under a certain pressure. The water comes out of the water delivery holes in a jet state, which can mix the water into the fly ash more evenly. The area of ​​the water delivery holes gradually expands along the water inlet direction to ensure that the spray flow rate of each hole is equal. The two adjacent water delivery holes along the water inlet direction are defined as water delivery hole 1 and water delivery hole 2, respectively. The average flow velocities of the two water delivery ports are v1 and v2, respectively, and the cross-sectional areas are A1 and A2, respectively.

[0046] According to the energy conservation equation:

[0047] Among them, λ is the resistance coefficient along the way, l is the length between the two outlets, d is the diameter of the water pipe, and ξ is the local resistance coefficient.

[0048] Since the water delivery distance is short and the water delivery pressure is large, it is assumed that the cross-sectional pressures of the two water delivery holes are equal, that is, p1=p2.

[0049] To ensure that the flow rate of each water delivery hole is equal, that is, A1v1=A2v2.

[0050] Bring in

[0051] Adjacent water delivery hole area ratio

[0052] Fig. 9 This is a structural diagram of the intermittent spiral scraping mud conveying box of the present invention. The conveying box structure includes an outer square and inner circle conveying box body, a fly ash slurry inlet, an additive inlet, an intermittent spiral, a mixing and stirring rod, a main rotating shaft, a metal square frame, a flexible rubber scraper, an explosion-proof motor and a mud outlet. The inside of the conveying box, the intermittent spiral, the mixing and stirring rod, the main rotating shaft and the surface of the metal square frame are all coated with a nano coating. The intermittent spiral, the mixing and stirring rod, the metal square frame and the flexible rubber scraper rotate in the direction of rotation of the main rotating shaft to output the modified fly ash slurry from the mud outlet. There are two intermittent openings inside the intermittent spiral. The slurry part pushed to the right flows out from the fracture and mixes with the slurry at the rear to generate a certain shear force, thereby improving the miscibility between different materials. The mixing and stirring rod and the intermittent spiral are arranged alternately to improve the mud mixing efficiency. The flexible rubber scraper is connected to the outside of the metal frame and is tangent to the inner surface of the conveying box. During the transportation of the modified fly ash slurry, it scrapes off the material on the inner wall of the conveying box to prevent the small amount of additives from sticking to the inner wall of the conveying box and failing to fully improve the performance of the fly ash slurry.

Claims

1. Dynamic delineation and coordinated prevention technology of spontaneous combustion areas of coal in goafs along goaf-retaining lanes, characterized in that: It consists of the technology of hierarchical dynamic delineation of coal spontaneous combustion areas in goafs along goaf-retained lanes and the technology of coordinated prevention and control of coal spontaneous combustion in goafs along goaf-retained lanes; the technology of hierarchical dynamic delineation of coal spontaneous combustion areas in goafs along goaf-retained lanes includes the three-dimensional real-time dynamic simulation of coal spontaneous combustion areas, the design of the two-dimensional monitoring system for coal spontaneous combustion in goafs and the hierarchical division of the risk index of coal spontaneous combustion areas; the technology of coordinated prevention and control of coal spontaneous combustion in goafs along goaf-retained lanes includes the multiple air leakage prevention technology on the wall of goaf-retained lanes and the fire prevention and extinguishing technology of blocking-inert-isolation-cooling-wrapping; The three-dimensional real-time dynamic simulation of the coal spontaneous combustion area is based on a full-scale physical model, porosity distribution function code programming, experimental determination of coal sample oxygen consumption rate, characteristic gas release rate, and heat release intensity. It visualizes the dynamic simulation behavior of the working face, analyzes the correlation between the coal spontaneous combustion evaluation index and the working face advancement speed and tunnel ventilation volume, and combines the on-site two-dimensional measurement results to predict the three-dimensional evolution trend of the catastrophic spontaneous combustion area. The two-dimensional monitoring system for spontaneous combustion of coal in goaf is designed to arrange temperature measuring optical fibers in a U-shaped staggered manner in the goaf along the goaf, and to add an L-shaped temperature measuring optical fiber in the predicted spontaneous combustion area of ​​coal along the goaf side. The optical fiber is placed in an elastic optical fiber protection device; bundle tube gas measuring points are arranged on both sides of the goaf, and the gas measuring points on the goaf side receive tracer gas; The elastic optical fiber protection device comprises a transparent retractable outer shell, a transparent retractable inner wall, a rotatable base, an elastic ball, a plastic spring, and a retractable sleeve; the rotatable base is embedded between the transparent retractable outer shell and the inner wall, and can rotate in a circular shape around the center of a circle along the hollow; six groups of elastic balls are connected to the rotatable base through a spinning caliper, and can spin in a horizontal direction; the elastic balls are connected to the plastic spring, and the plastic spring is wrapped with a retractable sleeve; The coal spontaneous combustion area hazard index tiered division is based on O2 concentration, air leakage rate, temperature rise gradient, and CO concentration as division indicators. The union of the four characteristic indicators is used as the potential coal spontaneous combustion area, and the intersection of 4 / 3 / 2 / 1 characteristic indicators is used as the extremely high risk / high risk / medium risk / low risk coal spontaneous combustion areas respectively. The extremely high risk coal spontaneous combustion area includes the area around the maximum temperature rise gradient or CO concentration. The critical temperature of spontaneous combustion and the corresponding CO concentration are used to determine the core spontaneous combustion disaster area where the coal sample begins to spontaneously heat up.

2. According to the technology for dynamic delineation and coordinated prevention of spontaneous combustion zones of coal in goafs along goaf-retaining lanes according to claim 1, it is characterized in that: The multiple air leakage prevention process for the wall of the goaf-retained tunnel comprises the following steps: before support, a multifunctional mining slurry spraying vehicle is used to spray inorganic polymer fly ash colloidal mud on the coal residue in the goaf area on the side of the goaf-retained tunnel; after support, inorganic polymer fly ash colloidal mud is sprayed on the outer surface of the support structure in sequence, thickened fireproof air duct curtains are hung, and high-viscosity and quick-setting fly ash mud is sprayed at the connection between the air duct curtains and the top and bottom of the tunnel.

3. According to claim 2, the technology for dynamic delineation and coordinated prevention of spontaneous combustion areas of coal in goafs along goaf-retaining lanes is characterized in that: The multifunctional pulping and spraying vehicle for mining comprises a vehicle body, a reverse hedging and anti-sedimentation mud mixing box, an intermittent spiral wall scraping mud conveying box, a mechanical arm spraying device and a telescopic camera device; the mixing box and the conveying box are connected by a one-way solenoid valve, and the mechanical arm spraying device is provided with a rotating base and a telescopic mechanical arm.

4. According to claim 3, the technology for dynamic delineation and coordinated prevention of spontaneous combustion areas of coal in goafs along goaf-retaining lanes is characterized in that: The interior of the reverse-hedging and anti-sedimentation mud mixing box is a combination structure of a rectangular parallelepiped and a chamfered platform, and the top feed port is provided with a dustproof shell and a porous equidistant arched material distribution rack; the internal mixing structure includes an annular high-pressure water supply hole, an outward-expanding folding-blade multi-layer agitator, a porous internally-thrown speed reducer, and a central inclined guide plate; the agitators on both sides rotate in opposite directions to the center, and the annular high-pressure water supply holes are arranged in the upper part of the mixing box, with equal distances and equal flow rates.

5. According to claim 3, the technology for dynamic delineation and coordinated prevention of spontaneous combustion areas of coal in goafs along goaf-retaining lanes is characterized in that: The intermittent spiral scraping mud conveying box consists of an intermittent spiral, a mixing stirring rod, a metal frame and a flexible rubber scraper. The surface of the stirring and conveying device is coated with a nano coating and rotates with the main shaft; there are two arc-shaped fractures inside the intermittent spiral; the flexible rubber scraper is connected to the outside of the metal frame and is tangent to the cylindrical inner surface of the conveying box.

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