Comprehensive management method of regional green precision grouting in re-mining coal seams

Abstract

The present invention discloses a comprehensive management method for regional green precision grouting of re-mined coal seams, and relates to the field of mining and safety technology. The method comprises the following steps: S1, accurately identifying and classifying the regional injection receiving space and disaster source status of the re-mined coal seams; S2, designing and arranging the multifunctional grouting pipeline structure according to the accurate identification and classification results of S1; S3, preparing green grouting slurry for re-mined coal seams; S4, using the grouting slurry prepared in S3 to grout the re-mined coal seams, and using a grouting monitoring system to monitor and feedback the grouting effect during the grouting process for dynamic control and adjustment. The present invention not only solves the technical bottleneck in the management of re-mined coal seams, but also realizes safe, efficient and green recovery of coal resources, which is of great significance for improving the economic benefits of coal enterprises, extending the service life of mines and ensuring national energy security. The promotion and application of this method will effectively promote the progress and development of my country's coal mine re-mining technology.

Description

Technical Field

[0001] The present invention belongs to the field of mining and safety technology, and in particular relates to a regional green precision grouting comprehensive management method for re-mining coal seams. Background Art

[0002] In the early days of coal mining in my country, due to the backward mining technology and mining design, many backward mining methods such as knife-pillar type, room-pillar type, high-drop type, and digging instead of mining (lane mining) appeared, resulting in a coal resource recovery rate of less than 30%, leaving behind a large amount of high-quality coal resources. Re-mining the remaining high-quality coal resources in the old mining area (hereinafter referred to as "re-mining") can not only increase the service life of coal enterprises and increase the economic benefits of enterprises, but also has important strategic significance for ensuring the long-term stable supply of national coal resources and energy security.

[0003] However, unlike the conventional complete coal seam mining method, there are a large number of empty tunnels, abandoned tunnels, and damaged areas such as collapse, spalling and roof fall ("old empty damaged areas") in the re-mined coal seams. At the same time, there are complex water accumulation in the old empty areas, harmful gases and other unknown disaster sources, which bring great safety hazards and challenges to the layout of the comprehensive mining working face and safe mining of the re-mined coal seams. In response to this problem, the current underground grouting technology is generally used in coal mine re-mining to treat the old empty areas exposed during the re-mining process (such as Chinese patents 201910359585.9, 202010532750.9, etc.), and the filling materials after grouting and the surrounding rock mass jointly bear the stress of the overlying rock strata, and repair and reinforce the surrounding rock of the old empty damaged area. However, existing engineering practices have shown that due to the constraints of underground space, it is difficult for underground grouting treatment methods to carry out large-scale grouting treatment of the entire working face or mining area as a whole. Generally, the "grouting as mining progresses" method is adopted, that is, grouting treatment is carried out after old empty areas are found during the advancement of the working face. This results in low treatment efficiency and high risk, which seriously affects the normal safe production of the re-mining working face.

[0004] Therefore, it would be an effective way to use ground grouting to treat the damaged areas of re-mined coal seams, such as Chinese patent 202111543371.0. However, key issues such as identification of the injected space of re-mined coal seams, drilling arrangement and construction, slurry preparation, grouting process control, and grouting effect detection have not been effectively solved in the existing ground grouting treatment methods. For this reason, it is urgent to invent a ground efficient, precise, and green grouting method that can be used for the treatment of multi-hazard old empty damaged areas in re-mined coal seams. Summary of the invention

[0005] The purpose of the present invention is to provide a regional green precision grouting comprehensive management method for re-mined coal seams, to provide a scientific method for solving the problems of old empty damaged areas and multiple disaster sources in re-mined coal seams from the source, and to ensure safe and efficient mining of re-mined coal seams.

[0006] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0007] The present invention is a regional green precision grouting comprehensive treatment method for re-mining coal seams, comprising the following steps:

[0008] S1, accurately identify and classify the regional injection space and disaster source status of the re-mined coal seam. This step includes:

[0009] S1.1, use geophysical methods to preliminarily identify the large space receiving injection and collect basic information;

[0010] S1.2, determine the drilling arrangement plan based on the geophysical information and drill the holes, obtain the structural characteristics of the large-space overburden strata through ground drilling and coring, and conduct macro-microscopic testing and analysis of the cores obtained in the laboratory;

[0011] S1.3, use a borehole peep probe to peer at the borehole location to determine the vertical distribution characteristics of the small space structure receiving injection;

[0012] S1.4, use cross-hole acoustic CT tomography to determine the lateral distribution characteristics of small injected space structures and the volume of large injected space within the geophysical exploration area;

[0013] S2, based on the accurate identification and classification results of S1, conduct the design and layout of the multifunctional grouting pipeline structure;

[0014] S3, preparing green grouting slurry for re-mining coal seams;

[0015] S4, use the grouting slurry prepared in S3 to grout the re-mined coal seam, and use the grouting monitoring system to monitor and feedback the grouting effect during the grouting process, so as to make timely adjustments to the grouting plan and the design and layout of the multi-functional grouting pipeline structure.

[0016] As a preferred technical solution of the present invention, in the geophysical preliminary identification step, the geophysical methods used include three-dimensional seismic and high-density electrical methods, and the basic information collected by the geophysical methods includes the distribution position of the injected space, the geometric size range, and the water accumulation state inside the injected space.

[0017] As a preferred technical solution of the present invention, S1.2 determines the drilling arrangement based on geophysical information, obtains the structural characteristics of the injected large-space overburden strata through ground drilling and coring, and simultaneously conducts macro- and micro-testing and analysis of the cores obtained by drilling in the laboratory.

[0018] As a preferred technical solution of the present invention, in S1.2, when determining the drilling arrangement plan based on geophysical information, the drilling arrangement I plan or W plan is selected according to the geometric characteristics of the large injected space projected on the coal seam plane and the maximum diffusion range of the grouting slurry.

[0019] As a preferred technical solution of the present invention, in the specific implementation of S1.4, a high-power CT discharge probe and a high-power CT receiving probe device are installed in the geophysical tube, and the specific installation method of the high-power CT discharge probe and the high-power CT receiving probe device is determined according to the drilling layout plan.

[0020] As a preferred technical solution of the present invention, S2 includes the design of the ground grouting vertical pipe structure, the installation of the grouting vertical pipe and the installation of the drainage pipe of the underground receiving space;

[0021] The slurry riser structure design includes:

[0022] The grouting inner tube is used for grouting into the large space to be grouted, and comprises an upper steel tube and a lower cuttable bamboo tube;

[0023] Grouting outer tube, which is used for grouting small spaces;

[0024] A geophysical exploration tube, which is used to place a cross-hole acoustic wave CT tomography detection device;

[0025] As a preferred technical solution of the present invention, in S3, when grouting the large space to be injected, a green high-toughness slurry is used, and the formula of the slurry is: ordinary Portland cement is used as a cementitious material, coal gangue and fly ash are used as the main materials for grouting, polycarboxylic acid high-efficiency water-reducing agent and bamboo fiber are used as auxiliary materials for grouting, and mine water is used to make slurry. The slurry ratio is: coal gangue: fly ash: ordinary Portland cement: mine water = 10:1:2:3; the coal gangue needs to be calcined and crushed, and the particle size does not exceed 0.5mm; the amount of polycarboxylic acid high-efficiency water-reducing agent is 0.5% of the mass of ordinary Portland cement; the bamboo fiber has a length of 10 to 40mm and a diameter of less than 0.2mm, and the amount does not exceed 3.0kg / m3.

[0026] As a preferred technical solution of the present invention, in S3, a green high-strength and high-fluidity slurry is used for grouting the large space to be injected. The formula of the slurry is: fly ash and ordinary Portland cement PO42.5 are selected as the main materials, polycarboxylic acid high-efficiency water reducer is used as the grouting auxiliary material, and mine water is used to make slurry. The slurry ratio is: fly ash: ordinary Portland cement PO42.5: mine water = 1:1.2:1.8, and the amount of polycarboxylic acid high-efficiency water reducer is 0.5% of the mass of ordinary Portland cement PO42.5.

[0027] As a preferred technical solution of the present invention, the grouting monitoring system in S4 includes: a grouting pressure sensor, a grouting flow sensor, a grouting data acquisition and uploading device, and a grouting information analysis device. The data monitored by the grouting monitoring system is grouting pressure (P)-flow (Q)-time (t), and a PQt curve is drawn in real time;

[0028] When grouting a large space, stop grouting when the grouting flow rate Q is lower than 10L / min, and wait for 6 hours for the slurry to fully expand and solidify. After grouting of 5 grouting pipes and the slurry fully expands and solidifies, perform cross-hole acoustic CT tomography detection, and obtain the grouting filling status of the large space based on the geophysical information, and adjust the next grouting process in time based on the geophysical results;

[0029] When grouting is carried out in a small space, the grouting is terminated when the grouting flow rate Q is lower than 5L / min. After grouting of every five grouting pipes, cross-hole acoustic CT tomography detection is carried out to obtain the filling situation of the fracture structure of the small space according to the geophysical information, and the next grouting process is adjusted in time according to the geophysical results.

[0030] As a preferred technical solution of the present invention, the grouting monitoring system, when adjusting the next grouting process according to the geophysical prospecting results, has the following specific solutions:

[0031] For large spaces:

[0032] If the volume of the large space to be grouted is filled by more than 90%, the current grouting parameters are maintained;

[0033] If the volume of the large space to be grouted is filled 50-90%, the grouting end condition is adjusted to a flow rate Q lower than 5L / min;

[0034] If the volume of the large space to be grouted is less than 50% filled, additional holes shall be drilled above the unfilled position for grouting;

[0035] If after grouting 10 grouting pipes, more than 30% of the large space volume in the area is still less than 50% filled, then when designing drilling holes in the area where drilling holes are not performed, adjust the theoretical grouting diffusion radius to 0.7 times the original radius, and adjust the relevant grouting parameters;

[0036] For small spaces:

[0037] If the small space crack structure is filled by more than 85%, keep the current grouting parameters;

[0038] If the small space crack structure is filled by 40-85%, the grouting end condition is adjusted to flow rate Q less than 3L / min;

[0039] If the filling of the small space crack structure is less than 40%, the grouting end condition is adjusted to a flow rate Q lower than 1L / min.

[0040] The present invention has the following beneficial effects:

[0041] The regional efficient, precise and green grouting method of the present invention targets the complex old empty damaged areas and disaster sources in the re-mined coal seams, and effectively solves the limitations of traditional underground grouting management methods through precise identification and classification, multi-functional grouting pipeline design, green grouting slurry preparation and real-time monitoring and adjustment, and realizes systematic and large-scale grouting management of the entire re-mining area, improves management efficiency and safety, ensures the safe and efficient recovery of coal resources, and is of great significance to improving the utilization rate of coal resources and ensuring national energy security.

[0042] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0044] Figure 1 It is the overall flow chart of the present invention.

[0045] Figure 2 This is a flow chart of S1 in the present invention.

[0046] Figure 3 It is a schematic diagram of the drilling arrangement I scheme mentioned in the present invention.

[0047] Figure 4 It is a schematic diagram of the drilling arrangement W scheme mentioned in the present invention. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] See also Figure 1-Figure 4 As shown, the present invention is a comprehensive management method for regional green precise grouting of re-mined coal seams, comprising the following steps: S1, accurately identifying and classifying the regional grouting receiving space and disaster source status of the re-mined coal seams; S2, designing and arranging the multifunctional grouting pipeline structure according to the accurate identification and classification results of S1; S3, preparing green grouting slurry for the re-mined coal seams; S4, using the grouting slurry prepared in S3 to grout the re-mined coal seams, and using a grouting monitoring system to monitor and feedback the grouting effect during the grouting process for dynamic control and adjustment.

[0050] A specific application of this embodiment is as follows: Step 1, accurately identify and classify the regional water injection space and disaster source status of the secondary mining coal seam.

[0051] The water injection space is the area to be grouted in the damaged area of the secondary mining coal seam. According to the space size, it is further divided into large water injection space and small water injection space. The large water injection space includes spaces such as the goaf of the coal seam, the cavity area of the old roadway, and the roof caving area; the small water injection space includes the coal seam fracture area, the roof fracture area, and the unfilled area after grouting in the large water injection space. Disaster sources include water accumulation, gas accumulation, etc.

[0052] Step 1.1 Geophysical prospecting for preliminary identification: According to the original mining geological and technical data of the damaged area of the secondary mining coal seam, use geophysical prospecting methods such as three-dimensional seismic and high-density electrical method to preliminarily identify basic information such as the distribution location, geometric dimension range, and internal water accumulation status of the large water injection space.

[0053] Step 1.2 Drilling and core sampling test: Based on the geophysical prospecting information of the large water injection space and combined with the later grouting requirements, determine the drilling layout plan. The drilling layout meets two requirements: on the one hand, it can obtain the overlying strata structure characteristics of the large water injection space through surface drilling and core sampling, and at the same time conduct macro and micro test analysis on the drilled cores in the laboratory to obtain physical property compositions, strength mechanical property parameters, etc. of rock masses in different horizons; on the other hand, the drilled holes can be used for later grouting, realizing multiple uses of one hole, saving construction costs and improving construction efficiency.

[0054] According to the geometric characteristics and parameters of the large water injection space in the plane projection of the coal seam, select different drilling layout plans. Let the minimum dimension of the large water injection space in the plane projection of the coal seam be L1, the maximum dimension be L2, and the maximum diffusion range of the grouting slurry be R:

[0055] (1) When L1 < R << L2, the large water injection space in the plane projection of the coal seam is in a "narrow and long strip shape". At this time, use the "I-shaped" plan to arrange the drilled holes, and the distance between adjacent drilled holes is less than R;

[0056] (2) When R << L1, the large water injection space in the plane projection of the coal seam is not in a narrow and long strip shape. At this time, use the "W-shaped" plan to arrange the drilled holes, and the distance between adjacent drilled holes is less than R.

[0057] Step 1.3 Borehole peeping test: Borehole peeping is carried out at the geophysical drilling location, and the borehole peeping probe is installed with a probe waterproof protective shell; the probe waterproof shell is made of a transparent plastic tube to prevent water from entering the borehole peeping probe. Detection is carried out step by step from the ground downward, and the detection ends when the borehole peeping probe reaches the bottom plate of the large injected space. Based on the detected borehole image, the digital image processing method is used to measure the change law of the aperture of the borehole wall cracks, and the vertical distribution law of the crack structure above the large injected space is determined based on this (that is, the vertical distribution characteristics of the small injected space structure); if there is water accumulation in the large injected space, the color of the borehole image will change, and the height of the water accumulation in the large injected space can be determined based on the image color change information.

[0058] Step 1.4 Inter-hole acoustic CT test: Use the cross-hole acoustic CT tomography method to determine the horizontal distribution characteristics of the fracture structure above the large space receiving injection (i.e. the lateral distribution characteristics of the small space receiving injection) and the volume of the large space receiving injection within the geophysical exploration area. Install the high-power CT discharge probe and the high-power CT receiving probe equipment in the geophysical exploration tube to achieve the reuse of the geophysical exploration process before and after grouting, and the comparison of the detection information before and after grouting.

[0059] like Figure 3 As shown in the figure: When the drilling holes are arranged in the "Type I" scheme, the high-power acoustic wave CT discharge probe (hereinafter referred to as the signal transmitting end) and the high-power acoustic wave CT receiving probe (hereinafter referred to as the signal receiving end) are sequentially placed in adjacent boreholes for installation, that is, A-1 is installed with the signal receiving end, A-2 is installed with the signal transmitting end; A-3 is installed with the signal receiving end, A-4 is installed with the signal transmitting end; and so on.

[0060] like Figure 4 As shown in the figure: When arranging the drilling holes in the "W-type" scheme, select the middle position to drill a hole to install the signal transmitter, and drill holes around to install the signal receiving end: drill holes B-1, A-1, A-2, and B-3 to install the signal receiving end, and drill hole B-2 to install the signal transmitter; drill holes B-4 and A-4 to install the signal transmitter, and drill hole A-3 to install the signal transmitter, and so on.

[0061] Step 2. Based on the accurate identification and classification results of step 1, the multifunctional grouting pipeline structure design and layout are carried out, including:

[0062] Ground grouting vertical pipe structure design: The grouting vertical pipe includes an inner grouting pipe, an outer grouting pipe, and a geophysical exploration pipe. The inner grouting pipe is mainly used for grouting into a large space to be grouted. It is connected by an upper steel pipe and a lower cuttable bamboo pipe. The connection point is located about 500mm above the large space to be grouted. The bamboo pipe enters the large space to a depth of about 200mm and has a diameter of 130mm. The bamboo pipe can be cut by a tunneling machine or a coal mining machine. The outer grouting pipe is used for grouting into a small space to be grouted. It is made of a steel pipe with a diameter of 150mm. The bottom of the steel pipe is located in the small space area to be grouted, and a slurry outlet hole is drilled on the wall of the steel pipe in this area. The geophysical exploration pipe is used to place a cross-hole acoustic CT tomography detection device, and the bottom is closed to prevent the grouting slurry from entering.

[0063] Installation of grouting vertical pipe: Grouting pipes are installed in the 1.2 drilling holes in turn to achieve multiple uses of one hole. Use a grout stopper to pressurize and seal the hole 60cm above the small space crack area.

[0064] Installation of underground receiving space drainage pipe. In order to facilitate the discharge of water and gas in the old empty area during grouting, underground receiving space drainage pipe and ground exhaust pipe are set up respectively. The starting point of underground receiving space drainage pipe is located at the lowest point of the receiving space, and the end point is located at the underground water pump room, which is connected by arranging drainage pipes and drainage ditches.

[0065] Step 3, preparing green grouting slurry for re-mining coal seams, which is specifically divided into:

[0066] Preparation of green high-toughness slurry for large space: Ordinary Portland cement is selected as the cementitious material, and coal-based solid waste materials such as coal gangue and fly ash are used as the main grouting materials, supplemented with polycarboxylic acid high-efficiency water reducer, bamboo fiber and other grouting auxiliary materials, to achieve the purpose of green high-toughness grouting in old empty areas and ensure that the strength of the grouting consolidation body meets the requirements of re-mining. Mine water is used for slurry preparation, and the slurry ratio for large-space grouting is: coal gangue: fly ash: cement: mine water = 10:1:2.0:3.0; coal gangue needs to be calcined and crushed, and the particle size does not exceed 0.5mm; the dosage of polycarboxylic acid high-efficiency water reducer is 0.5% of the cement mass; the bamboo fiber has a length of 10-40mm and a diameter of less than 0.2mm, and the dosage does not exceed 3.0kg / m3. It is mainly used to solve the brittle characteristics of the conventional coal-based solid waste slurry consolidation body, which is easy to cause spalling problems in the working face (old empty damaged area) during the recovery of the re-mining coal seam. By adding bamboo fiber when preparing the slurry, the ductility and tensile strength of the stone body can be effectively improved, and it is easy to be cut by the coal mining machine.

[0067] Preparation of green high-strength and high-fluidity slurry for small injected space: In order to achieve effective penetration, diffusion, repair and reinforcement of cracks in the damaged area of ​​the roof, fly ash-cement composite slurry is selected. The cement is ordinary Portland cement PO42.5, fly ash: cement: water = 1:1.2:1.8, supplemented with polycarboxylic acid high-efficiency water reducer, and the amount does not exceed 0.5% of the cement mass.

[0068] Step 4: Use the grouting slurry prepared in step 3 to grout the re-mined coal seam, and use a grouting monitoring system to monitor and feedback the grouting effect during the grouting process:

[0069] Ground grouting integrated control system: including ground cement silo, mobile grouting vehicle and grouting monitoring system.

[0070] The ground cement silo is used to store the prepared grouting materials. The mobile grouting vehicle is equipped with a grouting bucket, a mixing pump, and a grouting pump. The mobile grouting vehicle can quickly move to the location where pre-grouting is required, reduce the laying of grouting pipelines, and improve the grouting efficiency. The grouting bucket is used to store grouting slurry, and the mixing pump is used to fully mix the grouting aggregate. The grouting monitoring system includes a grouting pressure sensor, a grouting flow sensor, a grouting data acquisition and upload device, and a grouting information analysis device. The grouting pressure sensor, the grouting flow sensor, and the grouting data acquisition and upload device are installed in the mobile grouting vehicle, which can upload the grouting pressure, slurry flow and other information on the construction site to the information analysis device in real time, realizing real-time digital monitoring of grouting information.

[0071] Grouting sequence design:

[0072] (1) When using the "I-type" scheme to arrange the boreholes, grouting is performed in sequence along the "I-type". The grouting sequence is: A-1→A-2→A-3→A-4.

[0073] (2) When the "W-shaped" scheme is used to arrange the boreholes, grouting is performed in sequence along the "W-shaped". The grouting sequence is: B-1→A-1→B-2→A-2→B-3→A-3.

[0074] Grouting process and grouting effect detection feedback:

[0075] Use a mobile grouting vehicle to inject grout into the large space, use the grouting monitoring system to monitor the grouting pressure (P)-flow (Q)-time (t) in real time, draw the PQt curve in real time, and end the grouting when the grouting flow Q is lower than 10L / min. Wait for 6 hours for the grout to fully expand and solidify.

[0076] After grouting of each of the five grouting pipes is completed and the slurry is fully expanded and solidified, the cross-hole acoustic CT tomography method is used for detection. The grouting filling status of the large space is obtained based on the geophysical information. The next grouting process is adjusted in time according to the geophysical results:

[0077] (1) If the volume of the large space in the grouting completion area is filled by more than 90%, the grouting flow rate Q and grouting pressure P at the end of grouting remain unchanged.

[0078] (2) If the volume of the large space in the grouting completion area is filled by 50-90%, the next grouting process is adjusted to end the grouting when the grouting flow rate Q is less than 5 L / min.

[0079] (3) If the volume of the large space in the grouting completion area is less than 50% filled, additional holes should be drilled above the unfilled position of the large space for grouting.

[0080] (4) If, after grouting of 10 grouting pipes, more than 30% of the large spaces are filled with less than 50% of the volume after the initial grouting, the theoretical grouting diffusion radius shall be adjusted to 0.7 times the original diffusion radius when drilling holes are designed in the area where no drilling is performed, and the relevant grouting parameters shall be adjusted at the same time.

[0081] 4.3.2 Use a mobile grouting vehicle to inject slurry into the small space to be injected. Use the grouting monitoring system to monitor the grouting pressure (P)-flow (Q)-time (t) in real time, draw the PQt curve in real time, and stop grouting when the grouting flow Q is lower than 5L / min.

[0082] After grouting of every five grouting pipes, the small space to be injected is tested by cross-hole acoustic CT tomography. The filling situation of the fracture structure of the small space to be injected is obtained based on the geophysical information. The next grouting process is adjusted in time according to the geophysical results:

[0083] (1) If the small space crack structure in the grouting completion area is filled by more than 85%, the grouting flow rate Q and grouting pressure P at the end of grouting are kept unchanged.

[0084] (2) If the small space crack structure in the grouting completion area is filled by 40-85%, the next grouting process is adjusted to end the grouting when the grouting flow rate Q is lower than 3L / min.

[0085] (3) If the volume of the large space in the grouting completion area is less than 40%, the next grouting process is adjusted to end when the grouting flow rate Q is less than 1L / min.

[0086] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0087] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A comprehensive management method for regional green precision grouting in re-mining coal seams, characterized in that: The following steps are involved: S1, accurately identify and classify the regional injection space and disaster source status of the re-mined coal seam. This step includes: S1.1, use geophysical methods to preliminarily identify the large space receiving injection and collect basic information; S1.2, determine the drilling arrangement plan based on the geophysical information and drill the holes, obtain the structural characteristics of the large-space overburden strata through ground drilling and coring, and conduct macro-microscopic testing and analysis of the cores obtained in the laboratory; S1.3, use a borehole peep probe to peer at the borehole location to determine the vertical distribution characteristics of the small space structure receiving injection; S1.4, use cross-hole acoustic CT tomography to determine the lateral distribution characteristics of small injected space structures and the volume of large injected space within the geophysical exploration area; S2, based on the accurate identification and classification results of S1, conduct the design and layout of the multifunctional grouting pipeline structure; S3, preparing green grouting slurry for re-mining coal seams; S4, use the grouting slurry prepared in S3 to grout the re-mined coal seam, and use the grouting monitoring system to monitor and feedback the grouting effect during the grouting process, so as to make timely adjustments to the grouting plan and the design and layout of the multi-functional grouting pipeline structure.

2. The regional green precision grouting comprehensive treatment method for re-mining coal seams according to claim 1 is characterized in that: In the step S1.1, the geophysical exploration methods used include three-dimensional seismic and high-density electrical methods, and the basic information collected by the geophysical exploration methods includes the distribution position of the injected space, the geometric size range, and the water accumulation state inside the injected space.

3. The regional green precision grouting comprehensive treatment method for re-mining coal seams according to claim 2 is characterized in that: In S1.2, when determining the drilling arrangement scheme based on geophysical information, the drilling arrangement I scheme or W scheme is selected according to the geometric characteristics of the large space projected on the coal seam plane and the maximum diffusion range of the grouting slurry; wherein: When the large space receiving slurry is projected as a narrow strip on the coal seam plane, the I scheme is adopted, and the adjacent boreholes are arranged in an I-type, and the distance between adjacent boreholes is smaller than the maximum diffusion range of the slurry; When the large receiving space is projected as a non-narrow strip on the coal seam plane, the W scheme is adopted, and adjacent boreholes are arranged in a W shape, and the distance between adjacent boreholes is smaller than the maximum diffusion range of the slurry.

4. The regional green precision grouting comprehensive treatment method for re-mining coal seams according to claim 3 is characterized in that: In the specific implementation of S1.4, a high-power CT discharge probe and a high-power CT receiving probe device are installed in the geophysical exploration tube. The specific installation method of the high-power CT discharge probe and the high-power CT receiving probe device is determined according to the drilling layout plan.

5. The regional green precision grouting comprehensive treatment method for re-mining coal seams according to claim 4 is characterized in that: S2 includes the design of the ground grouting vertical pipe structure, the installation of the grouting vertical pipe and the installation of the drainage pipe in the underground receiving space; The grouting vertical pipe structure design includes: The grouting inner tube is used for grouting into the large space to be grouted, and comprises an upper steel tube and a lower cuttable bamboo tube; Grouting outer tube, which is used for grouting small spaces; Geophysical exploration tube: The geophysical exploration tube is used to place the cross-hole acoustic wave CT tomography detection device.

6. The regional green precision grouting comprehensive treatment method for re-mining coal seams according to claim 1 is characterized in that: In S3, when grouting the large space to be injected, the slurry formula used is: ordinary Portland cement is used as the cementitious material, coal gangue and fly ash are used as the main materials for grouting, polycarboxylic acid high-efficiency water-reducing agent and bamboo fiber are used as auxiliary materials for grouting, and mine water is used to make slurry. The slurry ratio is: coal gangue: fly ash: ordinary Portland cement: mine water = 10:1:2:3; the coal gangue needs to be calcined and crushed, and the particle size does not exceed 0.5mm; the amount of polycarboxylic acid high-efficiency water-reducing agent is 0.5% of the mass of ordinary Portland cement; the length of bamboo fiber is 10-40mm, the diameter is less than 0.2mm, and the amount does not exceed 3.0kg / m3.

7. The regional green precision grouting comprehensive treatment method for re-mining coal seams according to claim 6 is characterized in that: In S3, the slurry formula used for grouting the small space is: fly ash and ordinary Portland cement PO42.5 are selected as the main materials, polycarboxylic acid high-efficiency water reducer is used as the grouting auxiliary material, and mine water is used to make slurry. The slurry ratio is: fly ash: ordinary Portland cement PO42.5: mine water = 1:1.2:1.8, and the amount of polycarboxylic acid high-efficiency water reducer is 0.5% of the mass of ordinary Portland cement PO42.

5.

8. The regional green precision grouting comprehensive treatment method for re-mining coal seams according to claim 1 is characterized in that: The grouting monitoring system in S4 includes: a grouting pressure sensor, a grouting flow sensor, a grouting data acquisition and uploading device, and a grouting information analysis device. The data monitored by the grouting monitoring system are grouting pressure (P)-flow (Q)-time (t), and a PQt curve is drawn in real time; When grouting a large space, stop grouting when the grouting flow rate Q is lower than 10L / min, and wait for 6 hours for the slurry to fully expand and solidify. After grouting of 5 grouting pipes and the slurry fully expands and solidifies, perform cross-hole acoustic CT tomography detection, and obtain the grouting filling status of the large space based on the geophysical information, and adjust the next grouting process in time based on the geophysical results; When grouting is carried out in a small space, the grouting is terminated when the grouting flow rate Q is lower than 5L / min. After grouting of every five grouting pipes, cross-hole acoustic CT tomography detection is carried out to obtain the filling situation of the fracture structure of the small space according to the geophysical information, and the next grouting process is adjusted in time according to the geophysical results.

9. The regional green precision grouting comprehensive treatment method for re-mining coal seams according to claim 8 is characterized in that: The grouting monitoring system, when adjusting the next grouting process according to the geophysical exploration results, has the following specific scheme: For large spaces: If the filling of the large space is greater than 90%, keep the current grouting parameters; If the volume of the large space to be grouted is filled 50-90%, the grouting end condition is adjusted to a flow rate Q lower than 5L / min; If the volume of the large space to be grouted is less than 50%, additional holes should be drilled above the unfilled position for grouting; If after grouting 10 grouting pipes, more than 30% of the large space in the area is still filled less than 50% of the volume, then when designing drilling holes in the area where drilling holes have not been performed, adjust the theoretical grouting diffusion radius to 0.7 times the original radius, and adjust the relevant grouting parameters; For small spaces: If the filling of the small space crack structure is greater than 85%, keep the current grouting parameters; If the small space crack structure is filled by 40-85%, the grouting end condition is adjusted to flow rate Q less than 3L / min; If the filling of the small space crack structure is less than 40%, the grouting end condition is adjusted to a flow rate Q lower than 1L / min.

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