Goaf slurry filling automatic monitoring device and method

Abstract

The application discloses a goaf slurry filling automatic monitoring device and method, which comprises a filling substation, a monitoring substation and an underground total control terminal; with the forward movement of a coal mining face, a sensing optical cable is automatically arranged in a goaf; in the slurry filling process, the sensing optical cable temperature and strain parameters are monitored in real time through a demodulation host; the data of each substation are comprehensively processed through the underground total control terminal; the filling effect of each filling casing pipe slurry is evaluated; and whether to stop filling and the working face advancing after condensation are intelligently controlled. The application can judge the filling effect of the slurry and has good monitoring effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of coal mines, and relates to a goaf slurry filling automatic monitoring device and method. BACKGROUND

[0002] The ecological mining method of mining and filling simultaneously solves the problems of ecological environment destruction and mining and filling replacement contradiction caused by high-intensity mining of coal mines, and realizes low-cost and timely filling of a high-efficiency mining working face. The method performs ground horizontal hole directional drilling or underground horizontal hole directional drilling in the immediate roof rock layer above the fully-mechanized mining working face to be mined, forms a horizontal directional long drill hole extending along the strike of the fully-mechanized mining working face in the immediate roof rock layer, lowers a filling casing into the horizontal directional long drill hole to form a filling slurry filling channel, and in the process of mining the working face, the immediate roof rock layer collapses with mining, filling slurry is injected into the goaf through the filling channel, and the entire fully-mechanized mining working face operation is completed. The filling slurry mainly uses solid waste such as gangue and fly ash as main materials, and the solid waste is mixed and prepared into filling slurry after treatment and then injected into the goaf. In the filling process, the filling effect of the goaf slurry needs to be monitored in real time to avoid underfilling or overfilling of the slurry. A video monitoring system is usually arranged behind the hydraulic support, but the video monitoring mainly adopts subjective judgment of personnel on duty, and the efficiency is low. In addition, due to the limitation of the environment of the goaf, the on-site video cannot well judge the filling effect of the slurry under the conditions of darkness and large dust, and the monitoring effect is poor. Therefore, an automatic monitoring device and method for goaf slurry filling are urgently needed. SUMMARY

[0003] In view of the problems in the prior art, the purpose of the present application is to provide an automatic monitoring device and method for goaf slurry filling to solve the problems that the prior art cannot well judge the filling effect of the slurry and has poor monitoring effect.

[0004] In order to solve the above technical problems, the present application adopts the following technical solutions:

[0005] An automatic monitoring device for goaf slurry filling comprises filling sub-stations, a monitoring sub-station and an underground total control end. Each filling sub-station is arranged below the goaf of each filling casing, the monitoring sub-station is arranged at the middle position between the adjacent two filling sub-stations, and the data of the filling sub-stations and the monitoring sub-station are transmitted to the underground total control end for centralized monitoring through wireless transmission.

[0006] The present application also includes the following technical features:

[0007] Specifically, the filling substation and the monitoring substation each include a demodulation host, a cable storage winch and a distributed sensing optical cable, the demodulation host is arranged on a hydraulic support operation platform in the goaf and can monitor the data of the distributed sensing optical cable in the goaf in real time, the cable storage winch can store and pay out the distributed sensing optical cable, one end of the distributed sensing optical cable is connected to the demodulation host, and the other end is fixed at a reserved coal pillar at the rear of the goaf through an anchoring short section; as the coal mining face advances forward, the distributed sensing optical cable is passively paid out through the cable storage winch, is laid in the goaf to be filled, and automatically completes the pre-tensioning strain adjustment of the distributed sensing optical cable, and the data collected by the distributed sensing optical cable is monitored in real time through the demodulation host.

[0008] Specifically, the cable storage winch is provided with an upper pulley and a lower pulley; the distributed sensing optical cable is guided through the upper pulley and the lower pulley; the upper pulley is located above the rear part of the cable storage winch and is hung at the top plate of the hydraulic support; the upper pulley includes a hydraulic motor and an optical cable clamping piece, the optical cable clamping piece cooperates with the cable pay-out control system of the cable storage winch to make the optical cable always keep straight, preventing the cable from being loosened; the lower pulley is located below the rear part of the upper pulley and is installed on the baffle of the hydraulic support in the goaf, so that the optical cable keeps in the horizontal direction, and the optical cable extends into the goaf through the baffle through hole; the cable storage winch includes a cable storage reel, a cable arranging device and a cable pay-out control system; when the hydraulic support drives the cable storage winch to advance forward, the cable storage winch passively pays out the cable at a predetermined tension, and the cable pay-out control system alarms when the cable pay-out tension exceeds a threshold value, and the hydraulic support slows down the advancing speed.

[0009] Specifically, the distributed sensing optical cable adopts armored well logging optical cable, so as to ensure that the optical cable is not pulled off or broken by the slurry and the caving roof during the laying process.

[0010] Specifically, the anchoring short section includes a connecting joint, a lock and an anchor grab; the anchoring short section is locked with the armored steel wire of the distributed sensing optical cable through the connecting joint, before the working face is mined, the anchoring short section is first buried in the reserved coal pillar at a specified height, the lock is released, a compression spring is installed in the lock, the tail end anchor grab is pushed out by the spring, the anchor grab is automatically stretched out and supported on the inner wall of the coal pillar, and one end of the distributed sensing optical cable is locked and fixed in the coal pillar.

[0011] Specifically, the demodulation host includes a light source module, a photoelectric conversion module, a data acquisition module, a data processing module, a display module and a wireless transmission module; the light source module emits a laser light source, the laser light source is sent to the distributed sensing optical cable through a transmission optical cable, the optical signal returned by the distributed sensing optical cable is collected through a distributed echo reflection, and the temperature and strain information of different sections of the optical cable are identified after photoelectric conversion.

[0012] A goaf slurry filling automatic monitoring method is realized through the goaf slurry filling automatic monitoring device, and includes the following steps:

[0013] Step 1, setting each filling substation and monitoring substation: each filling substation is arranged in the goaf below each filling casing, and the monitoring substation is arranged at the middle position between the two adjacent filling substations;

[0014] Step 2, laying the distributed sensing optical cable: one end of the distributed sensing optical cable is fixed to the reserved coal pillar, the distributed sensing optical cable is reeled in and out by the cable storage winch and laid in the goaf in a horizontal straight state;

[0015] Step 3, pre-stretching the distributed sensing optical cable: since the optical cable in the initial state can only monitor the tensile deformation but cannot monitor the convergence deformation, the optical cable is pre-stretched after being laid to have a pre-strain, and the pre-stretching adjustment length of the optical cable is wherein ε0 is the pre-set pre-strain value of the optical cable, is the average strain value obtained for the tensile / compressive strain of each sampling point of each optical cable; the pre-stretching adjustment length Δy of the optical cable is fed back to the cable storage winch for pre-stretching adjustment of the distributed sensing optical cable;

[0016] Step 4, monitoring the strain of the distributed sensing optical cable and compensating the strain for temperature: the demodulation host detects the optical echo through the distributed echo reflection, and identifies the temperature and strain information of different sections of the optical cable through temperature compensation after photoelectric conversion, and the strain caused by temperature change is ε W :

[0017]

[0018] In the above formula, ε L is the tensile / compressive strain of the optical cable, ε is the total strain monitored by the demodulation host, t s is the delay time after the deformation of the optical fiber, t r is the delay time before the deformation of the optical fiber, c is the speed of light, N is the refractive index of the optical fiber, and k1 and k2 are the temperature-strain optical calibration factor and strain optical calibration factor respectively; through the formula, the demodulation host can monitor the temperature and strain parameters at different positions of the distributed sensing optical cable in real time;

[0019] Step 5, monitoring during the filling period: the distributed sensing optical cable under each filling casing is uniformly arranged with 7 sampling points, and the middle sampling point is located directly below the filling casing outlet, and the two monitoring substations distributed in parallel on the left and right sides of the filling casing are also uniformly arranged with 7 sampling points, so that 3×7 sampling points are distributed in a matrix around each filling casing outlet, forming a monitoring network for the slurry filling casing, the demodulation host monitors the strain value of the distributed sensing optical cable in real time, and adopts Gaussian filtering to comprehensively evaluate the 3×7 monitoring strain values around the filling casing, the size of the kernel K is 3×7, and the coefficient a ijWeight allocation, i = 1, ..., 3; j = 1, ..., 7, as shown in the following formula:

[0020]

[0021] Finally, the strain value ε within the corresponding range of the filling sleeve is obtained after Gaussian filtering. x When this value is greater than the filling threshold ε max When the filling is complete, the corresponding orifice slurry pump is automatically controlled to stop the slurry filling.

[0022] Step 6, Expansion period monitoring: After the slurry filling is stopped, the filling enters the expansion period. At this time, the slurry undergoes a hydration reaction, the internal temperature gradually rises, the filling body expands, and the demodulation host monitors the distributed sensing optical cable for tensile strain. The strain value continues to rise, and the demodulation host provides real-time temperature data at different locations of the distributed sensing optical cable. When the temperature exceeds the threshold, the demodulation host alarms and takes water-cooling measures at the corresponding locations to prevent fires in the goaf.

[0023] Step 7, Shrinkage Period Monitoring: When the demodulation host detects that the strain value of the distributed sensing optical cable begins to decrease, the filling enters the shrinkage period. A basic relationship function is established based on the strain values ​​corresponding to different slurry shrinkage periods, and the strain value ε within the corresponding range of the filling sleeve is obtained by Gaussian filtering. x and the strain value ε at the corresponding time s The system adjusts the solidification process in real time and automatically judges the filling effect based on the relationship between the solidification process and the filling effect.

[0024] Specifically, in step 7, when the filling enters the shrinkage period, the strain value ε is determined based on the shrinkage period t corresponding to different slurry types. s Establish the basic relational function as shown in the equation: ε s = ∞ f(t), where ε ∞ The value represents the ultimate strain during the shrinkage period. f(t) is a fundamental relationship function determined based on the different types of slurry. When t = 0, ε p It is the strain value corresponding to the end of the expansion period. When t→∞, f(t)=1.

[0025] Specifically, the characteristic feature is that, in step 7, determining the filling effect includes:

[0026] when When the slurry filling strength is higher than the standard value, the filling effect is good, and the setting time can be shortened. This is based on the monitored strain value ε. x Determine when to move the hydraulic support;

[0027] when At that time, the slurry filling effect met expectations and satisfied the requirements;

[0028] When the slurry coagulates slowly, the coagulation strength is low, the filling effect is poor, and the slurry ratio and filling process need to be re-determined according to the site working conditions.

[0029] Compared with the prior art, the present application has the following technical effects:

[0030] 1. The present application monitors the whole process of slurry filling period, expansion period and shrinkage period, automatically evaluates the filling effect of each filling casing slurry, and intelligently controls whether to stop filling and the working face after coagulation. The problem of automatic and effective monitoring of the camera due to the limitation of the environment of the goaf is solved.

[0031] 2. The present application automatically arranges the sensing optical cable in the goaf as the coal mining face moves forward. The anchor short section and the automatic cable laying winch can fix the distributed sensing optical cable at the specified position in the goaf, and automatically complete the pre-tensioning strain adjustment of the optical cable, solving the problem of ineffective arrangement of sensors in the goaf.

[0032] 3. The present application uses a distributed optical cable demodulation host to monitor the reflected spectrum signals of different sections of long distances in real time, which can reflect the strain and temperature dual parameters at different positions of the optical cable.

[0033] 4. The present application centrally monitors the demodulation data of the filling substation and the monitoring substation at the underground total control end, calculates the comprehensive strain value around the filling casing by the Gaussian filtering method, automatically judges the filling stage, comprehensively reflects the filling effect of the whole goaf, and guides the filling process. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a schematic diagram of the filling channel of the present application;

[0035] Figure 2 It is a schematic diagram of the slurry filling automatic monitoring device of the present application;

[0036] Figure 3 It is a distribution diagram of the sampling points of the filling substation and the sampling points of the monitoring substation of the present application.

[0037] The meanings of the various reference numerals in the drawings are as follows:

[0038] 1. Coal seam of coal mining face, 2. Direct roof rock layer, 3. Filling casing, 4. Monitoring substation, 5. Filling substation, 6. Underground total control end, 7. Hydraulic support, 71. Hydraulic support operation platform, 72. Hydraulic support baffle, 8. Cable storage winch, 9. Distributed sensing optical cable, 10. Upper pulley, 11. Lower pulley, 12. Anchor short section, 13. Reserved coal pillar, 14. Demodulation host, 15. Filling substation sampling point, 16. Monitoring substation sampling point. DETAILED DESCRIPTION

[0039] The goaf slurry filling process is as follows: ground horizontal hole directional drilling or underground horizontal hole directional drilling is carried out in the immediate roof rock layer above the coal seam of the fully mechanized mining face to be mined, the horizontal directional long drill hole extending along the strike of the fully mechanized mining face is formed in the immediate roof rock layer, the filling casing pipe is lowered into the horizontal directional long drill hole to form the filling slurry filling channel, during the mining process of the working face, the immediate roof rock layer collapses with mining, the filling slurry is injected into the goaf through the filling channel until the entire fully mechanized mining face operation is completed.

[0040] The present application provides a kind of goaf slurry filling automatic monitoring device and method, with coal mining face moves forward, slurry monitoring sensing optical cable will be arranged in goaf, in the process of slurry filling, by demodulation host real-time monitoring sensing optical cable temperature and strain parameters, by underground total control end to the data of each substation Comprehensive processing, assess each filling casing pipe slurry filling effect, and intelligent control whether to stop filling and the working face after coagulation advances.

[0041] The following gives the specific embodiments of the present application, it should be noted that the present application is not limited to the following specific embodiments, any equivalent transformation based on the technical solutions of the present application falls within the scope of the present application.

[0042] Example 1:

[0043] The present application provides a kind of goaf slurry filling automatic monitoring device, the device includes filling substation, monitoring substation and underground total control end;Wherein, each filling substation is arranged in the goaf below each filling casing pipe, monitoring substation is arranged at the intermediate position between adjacent two filling substations;The data of filling substation and monitoring substation are all transmitted to underground total control end for centralized monitoring by wireless transmission. For example Figure 1 It is a filling channel schematic diagram, horizontal directional long drill hole is drilled in the immediate roof rock layer 2 above the coal seam 1 of coal mining face, filling casing pipe 3 is located in the horizontal directional long drill hole, monitoring substation 4 and filling substation 5 are arranged in goaf, underground total control end 6 receives monitoring data by wifi.

[0044] Filling substation and monitoring substation both include demodulation host, cable storage winch and distributed sensing optical cable, demodulation host is arranged on the hydraulic support operation platform of goaf and can real-time monitoring goaf distributed sensing optical cable data, cable storage winch can store and release distributed sensing optical cable, one end of distributed sensing optical cable is connected with demodulation host, the other end is fixed in the reserved coal pillar behind goaf through anchor short section;With the forward advance of coal mining face, distributed sensing optical cable is passively released by cable storage winch, is arranged in the goaf to be filled, and automatically completes optical cable pre-tensioning strain adjustment, and the data collected by distributed sensing optical cable is monitored in real time by demodulation host.

[0045] The storage cable winch is provided with an upper pulley and a lower pulley; the distributed sensing optical cable is guided through the upper pulley and the lower pulley; the upper pulley is located above the rear part of the storage cable winch and is hoisted at the top plate of the hydraulic support; the upper pulley comprises a hydraulic motor and an optical cable clamping piece; the optical cable clamping piece cooperates with the cable-out control system to enable the optical cable to always maintain a straightened state and prevent the cable from loosening. The lower pulley is located below the rear part of the upper pulley and is installed on the baffle of the goaf hydraulic support, so that the optical cable maintains a horizontal direction, and the optical cable extends into the goaf through the baffle through hole. The storage cable winch comprises a cable storage reel, a cable distributor and a cable-out control system; when the hydraulic support advances forward, the storage cable winch is passively released at a predetermined tension; when the cable-out control system detects that the release tension exceeds a threshold value, an alarm is given, and the advancing speed of the hydraulic support is slowed down. As shown in FIG. Figure 2 As shown in FIG. 1, a slurry filling automatic monitoring device is shown in the figure, the hydraulic support 7 is located in the goaf, the filling substation 5 and the monitoring substation 4 each comprise a demodulation host 14, a storage cable winch 8 and a distributed sensing optical cable 9, the storage cable winch 8 is provided with an upper pulley 10 and a lower pulley 11, the demodulation host 14 is arranged on the goaf hydraulic support operation platform 71, the lower pulley 11 is installed on the goaf hydraulic support baffle 72, and the anchor short section 12 is fixed at the reserved coal pillar 13 at the rear of the goaf.

[0046] The distributed sensing optical cable adopts armored logging optical cable, which ensures that the optical cable will not be pulled off or crushed by the slurry and the collapsed roof during the laying process. The anchor short section comprises a connecting joint, a lock and an anchor grab; the anchor short section is locked with the armored steel wire of the optical cable through the connecting joint; before the working face is mined, the anchor short section is first buried in the reserved coal pillar at a specified height, the lock is released, the lock is internally provided with a compression spring, the spring pushes the tail end anchor grab out of the short section, the anchor grab is automatically stretched and supported on the inner wall of the coal pillar, and one end of the optical cable is locked and fixed to the coal pillar.

[0047] The demodulation host comprises a light source module, an optoelectronic conversion module, a data acquisition module, a data processing module, a display module and a wireless transmission module. The light source module emits a laser light source, which is sent to the distributed sensing optical cable through a transmission optical cable; the light signal returned by the distributed sensing optical cable is collected through a distributed echo reflection technology; the temperature and strain information of different sections (sampling resolution 0.5 meters) of the optical cable are identified after photoelectric conversion.

[0048] Embodiment 2

[0049] The embodiment provides a goaf slurry filling automatic monitoring method, which comprises the following steps:

[0050] Step 1, setting each filling substation and monitoring substation: each filling substation is arranged in the goaf below each filling casing pipe, and the monitoring substation is arranged at the middle position between two adjacent filling substations; the data of the filling substation and the monitoring substation are transmitted wirelessly to the underground total control end for centralized monitoring;

[0051] Step 2, Deploy distributed sensing optical cable: Bury the anchoring short section connected to one end of the distributed sensing optical cable at a specified height in the reserved coal pillar so that one end of the distributed sensing optical cable is locked and fixed to the reserved coal pillar. The distributed sensing optical cable is then retrieved and deployed in the goaf by the cable storage winch and kept in a horizontal and straight state.

[0052] Step 3, Pre-stretch the distributed sensing optical cable: Since the initial state of the optical cable can only monitor tensile deformation but not convergence deformation, it is pre-stretched after deployment to give it pre-strain. The pre-stretch adjustment length of the optical cable is... Where ε0 is the pre-set pre-strain value of the optical cable. The average strain value is obtained for the tensile / compressive strain at each sampling point on each optical cable;

[0053] Specifically, in actual monitoring projects, optical cables / fibers can only monitor tensile deformation, not convergent deformation. Therefore, after laying the optical cable, it is necessary to pre-stretch the fiber to ensure that the optical cable has a certain pre-strain. In the automatic monitoring project for slurry filling in goaf areas, during the laying process of the pre-stretched optical cable, one end of the cable is fixed, while the other end cannot reach the preset pre-strain value after laying due to factors such as the difference between the cable release speed of the cable storage winch and the forward speed of the coal mining machine. This prevents normal monitoring of the slurry filling effect. Therefore, fiber pre-stretching is necessary during the cable release process. Based on the previous laboratory slurry filling simulation test, the pre-stretch strain ε0 of the optical cable was set. The coal mining machine drove the hydraulic support forward 3 meters each time. After reaching the fixed position, the sensing optical cable was automatically tightened and laid in the goaf area to be filled. At this time, the average strain value of the optical cable in this section was monitored. The length y of the stretched optical cable can be expressed as: Therefore, for the optical cable to be stretched to a pre-strain of ε0, the cable needs to be lengthened by rotating the hydraulic motor in both the forward and reverse directions through the cable delivery control system. During the fiber optic cable conditioning process, the demodulation host monitors the average strain value of the fiber optic cable in that section in real time. The adjustment length Δy is calculated in real time by equation (2), and the adjustment length Δy is fed back to the cable length metering module of the winch cable output control system. The optical cable pretension strain is adjusted by the forward or reverse rotation of the hydraulic motor.

[0054] Step 4: Monitoring the strain of the distributed sensing optical cable and temperature compensation for strain monitoring: The demodulation host detects the optical echo through distributed echo reflection. After photoelectric conversion, temperature compensation is used to identify the temperature and strain information of different sections of the optical cable. Temperature changes cause the reflection spectrum of the distributed sensing optical cable to drift. The strain caused by temperature changes is ε. W , ε W It can be measured through temperature-compensated optical fiber:

[0055]

[0056] In the above formula, ε L is the cable tensile / compression strain, ε is the total strain monitored by the demodulation host, t s is the delay time after deformation of the optical fiber, t r is the delay time before deformation of the optical fiber, c is the speed of light, N is the refractive index of the optical fiber, k1 and k2 are the temperature-strain optical correction factor and strain optical correction factor, respectively, which need to be calibrated in laboratory simulation tests, and through the formula, the demodulation host can calculate the temperature and strain parameters at different positions of the cable in real time.

[0057] During the entire monitoring process, the different stages of filling can be intelligently judged through the monitoring data of the demodulation host, the filling effect can be evaluated, and the filling process can be guided. Through a large number of laboratory slurry filling simulation tests in the early stage, the strain evolution characteristics are analyzed, and the filling process can be divided into three stages, namely the filling period, the expansion period and the shrinkage period.

[0058] Step 5, filling period monitoring: the slurry particles continuously produce physical sedimentation due to gravity, causing the optical fiber to bend downward and appear tensile strain. The strain value in this stage shows unstable characteristics in size and area. At this time, the slurry is continuously fed through the orifice for filling. As the filling height of the slurry increases, the slurry gradually covers the monitoring optical cable, and the monitoring strain value of the optical cable tends to be stable. The demodulation host of each substation transmits the monitoring data to the underground total control end through the underground wifi wireless transmission through the wireless transmission module. The underground total control end comprehensively processes the data of each substation and judges whether the filling slurry process in different channels is completed in real time. This judgment is based on the Gaussian filtering principle. First, the goaf filling process is abstracted as a mathematical model. The working face advances 3 meters each time. The optical cable of the filling substation under each filling casing is uniformly arranged with 7 sampling points (the distributed optical cable sampling interval is set to 0.5 meters). The middle sampling point is located directly below the filling casing outlet, and two monitoring substations are distributed in parallel on the left and right sides of the filling casing. The optical cable of the monitoring substation is also uniformly arranged with 7 sampling points. Thus, 3x7 sampling points are distributed in a matrix around the filling casing outlet, forming a monitoring network for the filling casing, as shown in Figure 3 Fig. 2, 7 filling substation sampling points 15 and each of the 7 monitoring substation sampling points 16 on both sides thereof.

[0059] Since the slurry is a mixture, it has a certain fluidity and also has strong viscosity. Therefore, under the action of natural gravity, the slurry will show a shape of high in the middle and low on the four sides and continuously overflow to the surrounding to form an accumulation shape. Therefore, it is necessary to use Gaussian filtering to comprehensively evaluate the 3x7 monitoring strain values around the filling casing. The size of the kernel K is 3x7, and the coefficient a ij is distributed by laboratory simulation tests, as follows:

[0060]

[0061] Finally, the strain value ε within the corresponding range of the filling sleeve is obtained after Gaussian filtering. x When this value is greater than the filling threshold ε max When the filling is complete, the corresponding orifice slurry pump is automatically controlled to stop the slurry filling.

[0062] Step 6, Expansion period monitoring: After the slurry filling is stopped, the filling enters the expansion period. At this time, the slurry undergoes a hydration reaction, the internal temperature gradually rises, the filling body expands, and the demodulation host monitors the tensile strain of the optical cable. The strain value continues to rise, and the demodulation host provides real-time temperature data at different locations of the optical cable. When the temperature exceeds the threshold, the demodulation host alarms and takes water-cooling measures at the corresponding location to prevent fire in the goaf.

[0063] Step 7, Shrinkage Period Monitoring: When the demodulation host detects that the strain value of the distributed sensing optical cable begins to decrease, the filling enters the shrinkage period. A basic relationship function is established based on the strain values ​​corresponding to different slurry shrinkage periods, and the strain value ε within the corresponding range of the filling sleeve is obtained by Gaussian filtering. x and the strain value ε at the corresponding time s The system adjusts the solidification process in real time and automatically judges the filling effect based on the relationship between the solidification process and the filling effect.

[0064] Specifically, as the filling enters the shrinkage phase, the chemical reactions within the filling material cause the strain value to continuously decrease, while the strength of the filling material continuously increases. Based on previous laboratory studies of the slurry material under 90 days of standard curing, the strain coefficient was measured to study the strain evolution law of slurry shrinkage and coagulation. The strain value ε corresponding to the shrinkage period t for different slurry types was then determined. s Establish the basic relational function as shown in the equation: ε s = ∞ f(t), where ε ∞ The value represents the ultimate strain during the shrinkage period. f(t) is a fundamental relationship function determined based on the different types of slurry. When t = 0, ε p It is the strain value corresponding to the end of the expansion period. When t→∞, f(t)=1;

[0065] During the contraction phase, strain values ​​at different locations on the fiber optic cables of each filling substation and monitoring substation are monitored through the downhole central control terminal. Based on the aforementioned Gaussian filtering principle, the strain value ε within the corresponding range of each filling casing is obtained. x And compare ε x and the strain value ε at the corresponding time s The relationship between the filling effect and the filling quality is used to determine the filling effect.

[0066] when When the value of the monitored strain ε is greater than the value of the monitored strain ε x Judging the timing of the movement of the hydraulic support;

[0067] When the value of the monitored strain ε is greater than the value of the monitored strain ε When the value of the monitored strain ε is greater than the value of the monitored strain ε

[0068] When the value of the monitored strain ε is greater than the value of the monitored strain ε When the value of the monitored strain ε is greater than the value of the monitored strain ε

Claims

1. A method for automatically monitoring goaf slurry filling, characterized in that, The automatic monitoring device for goaf slurry filling is realized, and the device comprises filling sub-stations, monitoring sub-stations and an underground total control terminal; each filling sub-station is arranged in a goaf below each filling casing pipe, and the monitoring sub-station is arranged at an intermediate position between two adjacent filling sub-stations; data of the filling sub-stations and the monitoring sub-stations are transmitted to the underground total control terminal through wireless transmission for centralized monitoring; The filling sub-stations and the monitoring sub-stations each comprise a demodulation host, a cable storage winch and a distributed sensing optical cable; the demodulation host is arranged on a goaf hydraulic support operation platform and can monitor distributed sensing optical cable data of the goaf in real time; the cable storage winch can store and release the distributed sensing optical cable; one end of the distributed sensing optical cable is connected with the demodulation host, and the other end is fixed at a reserved coal pillar behind the goaf through an anchoring short section; as a coal mining face advances forward, the distributed sensing optical cable is passively released through the cable storage winch, is arranged in a goaf to be filled, and automatically completes a pre-tension strain adjustment of the distributed sensing optical cable; data collected by the distributed sensing optical cable are monitored in real time through the demodulation host. The method comprises the following steps: Step 1: setting each filling sub-station and monitoring sub-station: each filling sub-station is arranged in a goaf below each filling casing pipe, and the monitoring sub-station is arranged at an intermediate position between two adjacent filling sub-stations; Step 2: arranging the distributed sensing optical cable: one end of the distributed sensing optical cable is fixed at a reserved coal pillar, the distributed sensing optical cable is released and released through the cable storage winch and is arranged in the goaf in a horizontal and straight state; Step 3, pre-stretching the distributed sensing optical cable: since the initial state of the optical cable can only monitor the tensile deformation but cannot monitor the convergence deformation, the optical cable is pre-stretched after being laid to have a pre-strain, and the pre-stretching adjustment length of the optical cable is wherein, is a pre-set pre-strain value of the optical cable, is an average strain value obtained by each sampling point on each optical cable; the pre-stretching adjustment length of the optical cable is fed back to the cable storage winch to adjust the pre-stretching strain of the distributed sensing optical cable; Step 4, compensation of strain and temperature of distributed sensing optical cable: the demodulation host detects optical echo through distributed echo reflection, and identifies temperature and strain information of different sections of the optical cable through temperature compensation after photoelectric conversion. The strain caused by temperature change is : = In the above formula, is the tensile / compressive strain of the optical cable, is the total strain monitored by the demodulation host, is the delay time after the deformation of the optical fiber, is the delay time before the deformation of the optical fiber, c is the speed of light, and N is the refractive index of the optical fiber, and are the temperature-strain optical correction factors and the strain optical correction factor, respectively. Through the above formula, the demodulation host can calculate the temperature and strain parameters at different positions of the distributed sensing optical cable in real time. Step 5, filling period monitoring: 7 sampling points are uniformly arranged in the distributed sensing optical cable of each filling substation under the filling casing, the middle sampling point is located directly below the filling casing outlet, and two monitoring substations are also uniformly arranged with 7 sampling points on both sides of the filling casing, so that 3x7 sampling points are distributed around the filling casing outlet, forming a monitoring network for the filling casing, the strain value of the distributed sensing optical cable is monitored in real time by the demodulation host, and the 3x7 monitoring strain values around the filling casing are comprehensively evaluated by using Gaussian filtering, and the size of the kernel is 3x7, the coefficient weight distribution is determined through laboratory simulation test, as follows: Finally, the strain value in the range of the filling casing is obtained through Gaussian filtering When the value is greater than the filling threshold , it is considered that the filling is completed, at which time the automatic control of the slurry pump of the corresponding orifice is stopped. Step 6: monitoring in the expansion period: after stopping the slurry filling, the filling enters an expansion period; at this time, the slurry produces a hydration reaction, the internal temperature gradually rises, the filling body expands, the demodulation host monitors that the distributed sensing optical cable produces a tensile strain, the strain value continuously rises, the demodulation host real-time prompts temperature data at different positions of the distributed sensing optical cable, and when the temperature exceeds a threshold value, the demodulation host alarms, and a dewatering and cooling measure is taken at a corresponding position to prevent a goaf fire; Step 7, monitoring in the shrinkage period: when the demodulation host monitors that the strain value of the distributed sensing optical cable starts to drop, filling enters the shrinkage period, a basic relationship function is established according to the strain value corresponding to the shrinkage period of different slurries, and the strain value in the corresponding range of the filling casing pipe solved by the Gaussian filter is compared and the strain value at the corresponding moment , the coagulation process is adjusted in real time, and the filling effect is automatically judged.

2. The goaf paste filling automatic monitoring method according to claim 1, characterized in that, In step 7, when filling into the shrinkage period, the strain value corresponding to the shrinkage period t of different slurry types , the basic relationship function is established as follows: , wherein, is the limit strain value of the shrinkage period, is the basic relationship function determined according to different types of slurry, when t=0, , is the strain value corresponding to the end of the expansion period, when , .

3. The goaf paste filling automatic monitoring method according to claim 2, characterized in that, In the step 7, the judgment of the filling effect comprises: When the slurry filling strength is higher than the standard value, the filling effect is good, the coagulation waiting time can be shortened, and the monitoring strain value judges the timing of the hydraulic support movement; When the slurry filling effect meets the requirements. When The slurry coagulates slowly, has low coagulation strength and poor filling effect, and the slurry proportioning and filling process need to be re-determined according to the site working conditions.

4. The goaf paste filling automatic monitoring method according to claim 1, characterized in that, The cable storage winch is provided with an upper pulley and a lower pulley; the distributed sensing optical cable is guided through the upper pulley and the lower pulley; the upper pulley is located above a rear portion of the cable storage winch and is hung at a hydraulic support top plate; the upper pulley comprises a hydraulic motor and an optical cable clamping piece; the optical cable clamping piece cooperates with an out-cable control system of the cable storage winch to enable the optical cable to always keep a straight state and prevent the optical cable from being loosened; the lower pulley is located below a rear portion of the upper pulley and is installed on a hydraulic support baffle in the goaf to enable the optical cable to keep a horizontal direction; the optical cable extends into the goaf through a baffle through hole; the cable storage winch comprises a cable storage reel, a cable discharging device and an out-cable control system; when the hydraulic support drives the cable storage winch to advance forward, the cable storage winch passively releases the cable at a predetermined tension; when the out-cable control system monitors that the releasing tension exceeds a threshold value, an alarm is given, and the hydraulic support slows down the advancing speed.

5. The goaf paste filling automatic monitoring method according to claim 1, wherein, The distributed sensing optical cable adopts an armored logging optical cable to ensure that the optical cable cannot be pulled off or broken by the slurry and the collapsed roof during the optical cable arrangement.

6. The goaf paste filling automatic monitoring method according to claim 5, characterized in that, The anchor short section comprises a connecting joint, a lock, and an anchor grab; the anchor short section is locked with the armored steel wire of the distributed sensing optical cable through the connecting joint; before mining of the working face, the anchor short section is first buried at a specified height of the reserved coal pillar; the lock is released by releasing the lock; the lock is internally provided with a compression spring; the spring pushes out the tail end anchor grab; the anchor grab is automatically stretched out and supported on the inner wall of the coal pillar; and one end of the distributed sensing optical cable is locked and fixed to the coal pillar.

7. The goaf paste filling automatic monitoring method according to claim 1, wherein, The demodulation host comprises a light source module, an optoelectronic conversion module, a data acquisition module, a data processing module, a display module, and a wireless transmission module; the light source module emits a laser light source and sends the laser light source to the distributed sensing optical cable through a transmission optical cable; the light signal returned by the distributed sensing optical cable is collected through distributed echo reflection to collect light echoes; and after optoelectronic conversion, temperature and strain information of different sections of the optical cable are identified.

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