Coal seam gas interception and drainage outburst prevention method based on grouting solidification

Abstract

The invention discloses a coal seam gas interception and drainage outburst prevention method based on grouting solidification. The method comprises the steps that lug drill sites are dug on the two sides of a roadway, construction drilling is conducted according to drilling arrangement parameters, seamless steel pipes are inserted after rock debris is removed, and grouting pipes are arranged according to preset intervals; a grouting material is prepared to calculate the grouting amount, and grouting is sequentially completed from top to bottom according to a progressive pressure increasing scheme; full-section grouting holes are formed in the front of the roadway head-on, and grouting is conducted in a zoning and layering mode to form an inner-layer curing area and an outer-layer curing area; gas drainage holes are formed in the inner side and the outer side of the grouting area, and crossing or bedding gas extraction drill holes are formed through an auxiliary transportation roadway and a connection roadway; and the gas drainage holes in the inner side and the outer side of the curing area are connected with an extraction pipeline, and continuous extraction is conducted within the preset pressure range. According to the scheme, the gas of the deep well roadway passing through the fault zone or the coal seam group can be safely extracted.

Description

Technical Field

[0001] The present application relates to the field of gas extraction, and in particular to a coal seam gas interception and extraction and outburst prevention method based on grouting solidification. Background Art

[0002] The extraction technology of coal seam gas interception and outburst prevention refers to a comprehensive engineering and technical measure to pre-extract and control the gas in the coal seam by laying a specific extraction system in the coal seam during the coal mining process. This technology aims to reduce the gas content in the coal seam, prevent coal and gas outburst disasters, and ensure safe production in coal mines. Its core is to establish an effective gas extraction system through scientific engineering design and construction before coal seam mining to achieve efficient control of coal seam gas. It is mainly used in the prevention and control of coal and gas outburst mines, especially in mining areas with the following characteristics: coal mines with high gas content, complex geological structure, poor coal seam occurrence conditions, and high outburst risks. Through the implementation of this technology, the gas content in coal seams can be significantly reduced, the physical and mechanical properties of coal seams can be improved, and the occurrence of coal and gas outburst accidents can be effectively prevented. At the same time, the comprehensive utilization of gas resources can be achieved, which has significant economic and social benefits.

[0003] Traditional gas control methods mainly include hydraulic fracturing and permeability enhancement technology, which is another commonly used gas control method. A fracture network is formed in the coal seam through high-pressure water jets to improve the permeability of the coal seam. However, this technology is greatly restricted by coal seam conditions and has problems such as large equipment investment and high engineering costs. Fracturing technology injects fracturing fluid into the coal seam to form artificial fractures in the coal seam to improve the permeability of the coal seam. Although this technology has obvious effects, it has environmental pollution risks and may affect the stability of the coal seam. Existing gas control technologies generally have the problems of low extraction efficiency and small impact range. Limited by the permeability of coal seams, it is often necessary to lay a large number of boreholes to achieve effective extraction, which not only increases engineering investment, but also prolongs the control cycle. It has poor adaptability under complex geological conditions. In areas with developed faults and folds, conventional extraction methods are difficult to accurately locate high-gas enrichment areas, resulting in unsatisfactory extraction effects and inability to effectively prevent the occurrence of outburst accidents.

[0004] Therefore, there is an urgent need for a technical solution that can safely extract gas from deep mine tunnels passing through fault zones or coal seam groups. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the embodiment of the present application discloses a coal seam gas interception and extraction and outburst prevention method based on grouting solidification. The present application solves the technical problems of the prior art such as high construction difficulty and high risk.

[0006] The embodiment of the present application discloses a coal seam gas interception and extraction and outburst prevention method based on grouting solidification, comprising: drilling ear drill sites on both sides of the tunnel, drilling according to drilling arrangement parameters, inserting seamless steel pipes after cleaning rock cuttings, and arranging grouting pipes at preset intervals; preparing grouting materials to calculate the grouting volume, and completing grouting in sequence from top to bottom according to a progressive pressure-increasing scheme; arranging full-section grouting holes in front of the tunnel head, and grouting in a zoned and layered manner to form inner and outer solidification zones; including: arranging full-section grouting holes within a specified range in front of the tunnel head; arranging the preset intervals along the tunnel cross-section contour. The grouting holes are arranged at a certain distance and polyethylene pipes are installed; the grouting is carried out in a zoned and layered manner, and the section is divided into three areas: upper, middle and lower; the area of ​​the solidification area is calculated according to the distance from the tunnel contour line to the boundary of the solidification area, so as to divide each area into two layers of inner and outer solidification areas for grouting; gas drainage holes are arranged inside and outside the grouting area, and through-layer or along-layer gas drainage holes are arranged through auxiliary transport lanes and connecting lanes; the gas drainage holes inside and outside the solidification area are respectively connected to the drainage pipelines, and continuous drainage is carried out within a preset pressure range; including: the drainage is controlled based on the nonlinear equation of gas flow; the nonlinear equation includes: ,in, represents the extraction flow at time t, represents the coal seam permeability, represents the original coal seam pressure, Indicates the negative pressure of extraction. represents the pressure attenuation coefficient, Indicates the dynamic viscosity of gas, is the gas constant, Indicates absolute temperature.

[0007] In a possible implementation method, ear drilling sites are excavated on both sides of the tunnel, drilling is carried out according to drilling arrangement parameters, seamless steel pipes are inserted after cleaning the rock cuttings, and grouting pipes are arranged at preset intervals, including: excavating ear drilling sites on one side or both sides of the tunnel, the clear section of the ear drilling sites is not less than a specified size; determining the number of single-row holes and the number of rows of holes according to the width and height of the tunnel section; using a hydraulic crawler drilling rig to construct holes in sequence according to preset intervals and inclinations; using compressed air to clean the rock cuttings in the boreholes, and inserting seamless steel pipes into the boreholes; arranging grouting pipes at preset intervals outside the tunnel contour line, and completing the layout in a top-to-bottom order.

[0008] In a possible implementation, grouting materials are prepared to calculate the grouting volume, and the grouting is completed in sequence from top to bottom according to a progressive pressure-increasing scheme, including: selecting ordinary Portland cement as the base material, and preparing the grouting materials according to a preset mass ratio; calculating the theoretical grouting volume of a single borehole according to the borehole diameter and length; calculating the required amount of grouting material according to the overflow coefficient; using a grouting pump to transport the grouting material through a high-pressure hose; using a progressive pressure-increasing scheme for grouting, and completing the grouting in sequence from top to bottom.

[0009] In one possible implementation, gas extraction holes are arranged inside and outside the grouting area, and through-layer or along-layer gas extraction boreholes are arranged through auxiliary transport tunnels and connecting tunnels, including: arranging a gas extraction system in the same direction as the grouting holes; arranging gas extraction holes inside and outside the grouting area respectively; within a specified range outside the solidification area, through-layer or along-layer gas extraction boreholes are arranged through adjacent auxiliary transport tunnels and connecting tunnels.

[0010] In one possible implementation, the gas extraction holes inside and outside the solidification zone are respectively connected to the extraction pipeline, and continuous extraction is carried out within a preset pressure range, including: connecting the gas extraction holes inside the solidification zone to the extraction pipeline; continuously extracting the gas inside the solidification zone; connecting the gas extraction holes outside the solidification zone to the extraction pipeline; continuously extracting the gas outside the solidification zone; maintaining the extraction pressure within a preset range.

[0011] In a possible implementation, the number of single-row drill holes and the number of rows of drill holes are determined according to the width and height of the tunnel section, including: , ,in, Indicates the number of holes drilled in a single row. Indicates the width of the tunnel section. Indicates the tunnel section height, Indicates the number of rows of holes drilled, Indicates a round-up operation.

[0012] In a possible implementation, the area of ​​the solidification zone is calculated according to the distance from the tunnel contour line to the boundary of the solidification zone, so as to divide each area into two inner and outer solidification zones for grouting, including: , ,in, Represents the theoretical area of ​​the inner solidification zone, Indicates the reference distance from the tunnel contour to the boundary of the solidification zone. Represents the theoretical area of ​​the outer solidification zone.

[0013] In a coal seam gas interception and extraction method for preventing coal outbursts based on grouting and solidification as disclosed above, the embodiment of the present application uses the pipe-roof grouting support technology to advance the surrounding rock of the front tunnel to prevent roof fall-induced outbursts. Furthermore, in some embodiments, the full-section coal rock mass of the front tunnel is reinforced by grouting and solidification technology to improve the structure of the coal rock mass and reduce the outburst index K1 value. Furthermore, in some embodiments, the gas isolated after grouting and solidification is extracted from the fault group section coal seam group area through the interception and extraction holes, forming a grouting, solidification, interception and extraction comprehensive coal outburst prevention and uncovering technology system, which can safely and quickly extract gas from deep well tunnels through fault zones or coal seam groups. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 A schematic diagram of a process for coal seam gas interception and extraction and outburst prevention method based on grouting solidification disclosed in an embodiment of the present application; Figure 2A A schematic diagram of the first section structure of a shed pipe disclosed in an embodiment of the present application; Figure 2B A schematic diagram of other sections of a shed pipe structure disclosed in an embodiment of the present application; Figure 3 A schematic diagram of the design of a pipe shed grouting and curing hole outside the tunnel outline disclosed in an embodiment of the present application; Figure 4 A schematic diagram of a gas extraction drilling arrangement disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0016] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure unless otherwise specifically stated.

[0017] Those skilled in the art can understand that the terms "first", "second" and the like in the embodiments of the present disclosure are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor represent the necessary logical order between them. It should also be understood that in the embodiments of the present disclosure, "multiple" can refer to two or more, and "at least one" can refer to one, two or more. It should also be understood that for any component, data or structure mentioned in the embodiments of the present disclosure, in the absence of explicit limitation or contrary revelation given in the context, it can generally be understood as one or more. In addition, the term "and / or" in the present disclosure is only a description of the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present disclosure generally indicates that the associated objects before and after are an "or" relationship. It should also be understood that the description of each embodiment in the present disclosure emphasizes the differences between the embodiments, and the same or similar parts can refer to each other. For the sake of brevity, they will not be repeated one by one.

[0018] At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. The techniques, methods and devices known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered part of the specification. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0020] Figure 1 A schematic flow chart of a coal seam gas interception and extraction and outburst prevention method based on grouting solidification disclosed in an embodiment of the present application.

[0021] like Figure 1As shown, in step S101, ear drilling sites are excavated on both sides of the tunnel, drilling is carried out according to the drilling arrangement parameters, and seamless steel pipes are inserted after cleaning the rock cuttings, and grouting pipes are arranged at a preset spacing. This includes: excavating ear drilling sites on one side or both sides of the tunnel, and the clear section of the ear drilling sites is not less than the specified size; determining the number of single-row drilling holes and the number of drilling rows according to the width and height of the tunnel section; using a hydraulic crawler drilling rig to construct drilling holes in sequence according to the preset spacing and inclination; using compressed air to clean the rock cuttings in the boreholes, and inserting the seamless steel pipes into the boreholes; arranging grouting pipes at the preset spacing outside the tunnel contour line, and completing the layout in a top-to-bottom order.

[0022] Among them, the number of single-row drilling holes and the number of rows of drilling holes are determined according to the width and height of the tunnel section, including: , ,in, Indicates the number of holes drilled in a single row. Indicates the width of the tunnel section. Indicates the tunnel section height, Indicates the number of rows of holes drilled, Indicates a round-up operation.

[0023] Specifically, for the coal burst prevention process under deep mine conditions, it is necessary to dig an ear drill site at a distance of 1.8-2.2m from the tunnel wall on one or both sides of the tunnel. The layout of the ear drill site needs to consider the operating space of the drilling equipment and the pipeline layout requirements. Preferably, the clear section of the ear drill site is not less than 2.5m×2.0m.

[0024] According to the size of the tunnel section, the drilling arrangement parameters can be calculated as follows: Assuming the tunnel section width is W (m) and the height is H (m), the number of single-row drill holes N≈W / 0.5+1 (round up), and the number of drill hole rows M≈H / 0.5+1 (round up). For example, for a typical tunnel section with a width of 4.8m and a height of 3.9m, the number of single-row drill holes is about 11, the number of drill hole rows is about 9, and the total number of drill holes is about 99. In actual construction, the drilling spacing can be appropriately adjusted according to specific geological conditions and support requirements.

[0025] In one embodiment, a ZDY-4000L fully hydraulic crawler drill rig can be used, equipped with a drill bit with a diameter of 92-96 mm and a drill rod with an outer diameter of 48-52 mm and a length of 700-780 mm. When arranging the drilling holes, a borehole is drilled every 0.48-0.52 m from the ear drilling site to the excavation direction, and the borehole is tilted downward at an angle of -5° to -7°. The specific inclination can be appropriately adjusted according to the geological conditions. In practical applications, the drilling depth is usually 5-60 m, and the specific depth should be determined in combination with the geological structure characteristics.

[0026] After the drilling construction is completed, the rock cuttings in the borehole must be cleaned immediately with compressed air. After the hole is cleaned, a seamless steel pipe with a specification of (38-42mm) × (5.8-6.2mm) × (2900-3100mm) is inserted into the borehole. Outside the tunnel contour line, a row of grouting pipes is preferably arranged every 480-520mm, and the angle between two adjacent rows of grouting pipes should be maintained within the range of 1.8°-4.2°. In one embodiment, the drilling and pipeline layout work of the upper area, the middle area and the lower area can be completed in sequence from top to bottom.

[0027] At step S102, grouting materials are prepared to calculate the grouting volume, and grouting is completed in sequence from top to bottom according to the progressive pressure increase scheme. This includes: using ordinary silicate cement as the base material, and preparing the grouting materials according to the preset mass ratio; calculating the theoretical grouting volume of a single borehole according to the borehole diameter and length; calculating the required grouting material dosage according to the overflow coefficient; using a grouting pump to transport the grouting material through a high-pressure hose; using a progressive pressure increase scheme for grouting, and completing the grouting in sequence from top to bottom.

[0028] Specifically, on the basis of ensuring the quality of drilling construction, grouting materials need to be prepared. In a preferred embodiment, P.042.5R ordinary Portland cement is selected as the base material, and is matched with special admixtures and water glass. The specific ratio adopts the mass ratio of cement: admixture water glass = 1: (0.78-0.82): (0.048-0.052). The grouting equipment can use the KPB-90EX grouting pump, whose rated grouting volume is 185-190L / min. The grouting system uses two-way high-pressure hose delivery to ensure the uniformity and stability of the grouting pressure and flow.

[0029] The calculation method of grouting volume is as follows: For a single borehole, its theoretical volume V (m 3 )=π×(D / 2) 2 ×L, where D is the borehole diameter (m) and L is the borehole length (m). Taking the borehole depth of 52m and the borehole diameter of 94mm as an example, the calculated single hole volume is approximately 0.361m 3 Taking into account the loss and overflow in the actual grouting process, it is recommended that the material preparation amount should be 1.2-1.3 times the theoretical calculated amount. Based on this, the required cement dosage is about 351kg, the admixture dosage is about 281kg, and the water glass dosage is about 18kg.

[0030] During the grouting process, a progressive pressure increase scheme should be adopted, that is, starting from 0MPa and gradually increasing to 5.8-6.2MPa. In actual operation, it is advisable to use 0.5MPa as the step unit, maintain each pressure level for 3-5 minutes, and observe the grouting effect. When the grouting material is observed to overflow from the adjacent hole, the stop valve of the grouting hole should be closed immediately. For all grouting holes in the ear drilling site, grouting needs to be completed in order from top to bottom.

[0031] In step S103, full-section grouting holes are arranged in front of the tunnel head, and grouting is performed in a zoned and layered manner to form two layers of solidified areas, including: arranging full-section grouting holes in a specified range in front of the tunnel head; arranging grouting holes at preset intervals along the tunnel section contour and installing polyethylene pipes; grouting is performed in a zoned and layered manner to divide the section into three areas, upper, middle and lower; the area of ​​the solidified area is calculated based on the distance from the tunnel contour line to the boundary of the solidified area, so as to divide each area into two layers of solidified areas, inner and outer, for grouting.

[0032] Among them, the area of ​​the solidification zone is calculated according to the distance from the tunnel contour line to the boundary of the solidification zone, so as to divide each area into two layers of inner and outer solidification zones for grouting, including: , ,in, Represents the theoretical area of ​​the inner solidification zone, Indicates the reference distance from the tunnel contour to the boundary of the solidification zone. Represents the theoretical area of ​​the outer solidification zone.

[0033] Preferably, full-section grouting holes need to be arranged within 45-55m in front of the tunnel. Using the same drilling equipment as above, a row of grouting holes is arranged every 0.95-1.05m along the tunnel section profile. In practical applications, PE pipes with specifications of (48-52mm) × (5.8-6.2mm) × (4900-5100mm) can be selected and installed in place. The preparation method of grouting materials and the grouting pressure control parameters are the same as above.

[0034] During construction, the grouting should be carried out after the grouting overflows from the adjacent holes before the next hole section is constructed. Preferably, the grouting can be carried out in a zoned and layered manner, that is, the section is divided into three areas: upper, middle and lower, and each area is further divided into two inner and outer solidification areas. This method helps to form a uniform and continuous isolation zone with a thickness of 1.8-2.2m.

[0035] The following method can be used to determine the scope of the solidification zone: set the reference distance from the tunnel contour to the boundary of the solidification zone as R (m), then the theoretical area of ​​the inner solidification zone is π×[(R+2) 2 -R 2 ], the theoretical area of ​​the outer solidification zone is π×[(R+4) 2-(R+2) 2 ]. In actual construction, the scope of the solidification zone can be appropriately adjusted according to geological conditions and support requirements, but a continuous and stable solidification zone should be formed.

[0036] In step S104, gas extraction holes are arranged inside and outside the grouting area, and through-layer or along-layer gas extraction boreholes are arranged through auxiliary transport tunnels and connecting tunnels. This includes: arranging a gas extraction system in the same direction as the grouting holes; arranging gas extraction holes inside and outside the grouting area respectively; and arranging through-layer or along-layer gas extraction boreholes through adjacent auxiliary transport tunnels and connecting tunnels within the specified range outside the solidification area.

[0037] After the grouting and curing process is completed, a gas extraction system needs to be arranged in the same direction as the grouting hole. Specifically, gas extraction holes are arranged inside and outside the grouting area, and their number corresponds to the grouting holes. In one embodiment, the drilling depth can be set to 5-60m, and the specific depth should be determined according to geological conditions and gas storage characteristics.

[0038] Within the range of 15-18m outside the grouting solidification area, through the adjacent auxiliary transport tunnels and connecting tunnels, through-layer or along-layer gas extraction boreholes are arranged. The design of the extraction system should consider the rationality of the pipeline layout and the requirements of extraction efficiency. In a preferred embodiment, the extraction pipeline is connected to the mine gas extraction system to maintain the extraction pressure within the range of 14.5-15.5kPa.

[0039] At step S105, the gas drainage holes inside and outside the solidification zone are respectively connected to the drainage pipeline, and continuous drainage is performed within a preset pressure range. This includes: connecting the gas drainage holes inside the solidification zone to the drainage pipeline; continuously draining the gas inside the solidification zone; connecting the gas drainage holes outside the solidification zone to the drainage pipeline; continuously draining the gas outside the solidification zone; and maintaining the drainage pressure within a preset range.

[0040] Preferably, the gas extraction holes on the inner side of the solidification zone are connected to the extraction pipeline for continuous extraction. The gas extraction holes on the outer side of the solidification zone are also connected to the extraction pipeline for continuous extraction. When connecting the extraction pipeline, a nonlinear control equation for the gas extraction flow is established based on the characteristics of the grouting solidification area formed by the steps described above. First, the gas extraction holes on the inner and outer sides of the solidification zone are connected to the gas collecting main pipe using seamless steel pipes with a diameter of 38-42mm respectively. The gas collecting main pipe adopts a seamless steel pipe with a diameter of 108-112mm and is laid along the direction of travel of the tunnel. For each extraction hole, a DN40 ball valve and a check device are installed at the connection with the gas collecting main pipe.

[0041] Considering the influence of the grouting material ratio (cement: admixture: water glass = 1: (0.78-0.82): (0.048-0.052)) on the permeability of the coal seam in step S102, and the characteristics of the 1.8-2.2 m thick isolation zone formed in step S103, the nonlinear control equation of the gas extraction flow is established: , where: is the extraction flow rate at time t (m³ / min); is the coal seam permeability (m²), which is inversely proportional to the grouting solidification degree. For the fully solidified area, the value range is (0.85-1.15)×10 -15 m 2 ; is the original coal seam pressure (kPa), measured based on the gas extraction system arranged in the fourth step; is the extraction negative pressure (kPa); is the pressure attenuation coefficient, and its value is related to the diffusion radius of the grouting material, ranging from 0.0028-0.0032min -1 ; is the gas dynamic viscosity, which is (1.08-1.12)×10 -5 Pa·s; is the gas constant, 8.314 J / (mol·K); is the absolute temperature (K). This equation is the dynamic process of coal seam gas desorption-diffusion-seepage after grouting solidification. Among them, The term characterizes the pressure decay law, The term reflects the cumulative effect of gas extraction over time. Controlled within the range of 14.5-15.5kPa. Based on this equation, when t=360min, if If it is less than 0.1m³ / min, it means that the gas outburst under the current extraction negative pressure has reached its limit, and the extraction negative pressure needs to be appropriately increased by 0.8-1.2kPa.

[0042] The initial negative pressure of the drainage hole outside the solidification zone is set to 12.8-13.2 kPa. According to the equation calculation, when the pressure difference between the inside and outside is 1.6-2.4 kPa, a stable pressure gradient can be formed in the grouting solidification zone. According to the calculation results of the nonlinear control equation, the DN40 ball valve opening of each drainage hole It can be determined by the following relationship: , where It is the maximum flow rate when the ball valve is fully opened. In the actual extraction process, the calculated ball valve opening value is rounded to a multiple of 5%. When the gas concentration of a single drainage hole drops below 5% and continues for 72 hours All less than 0.05m3 / min, the ball valve of the hole can be closed. For the inner side of the solidification zone, when the coal seam gas pressure drops below 0.74MPa, P2 is adjusted to the range of 11.5-12.5kPa. The extraction work outside the solidification zone continues, keeping the original parameters unchanged.

[0043] When arranging the pipeline system, a connection point between the gas collecting branch pipe and the main pipe is set every 48-52m. A water-sealed gas collecting device is installed at the connection point, and the water seal height is maintained at 180-220mm. When laying the pipeline, a slope of 2.0-2.4° is maintained. The pipe section connection adopts flange connection, and the connection is sealed with a nitrile rubber gasket with a thickness of 2.8-3.2mm. When the water accumulation position in the pipeline exceeds 1 / 4 of the pipe diameter, open the drain valve to drain the water.

[0044] Figure 2A and Figure 2B They are schematic diagrams of the first section structure of a roof pipe and other sections of the roof pipe disclosed in the embodiments of the present application. It should be understood that the system shown in the figure is exemplary and not restrictive. This means that the structure involved is not limited to a specific form or design, but is presented as an example. In other words, the structure shown in the figure can be regarded as a way of expression to clearly describe related concepts and relationships, and does not exclude other forms of structures. Therefore, when interpreting the structure in the picture, it should be understood that the structure has flexibility and diversity, and its purpose is to disclose an exemplary description rather than a restrictive provision on a specific form. Figure 2A and Figure 2B The two components of the grouting pipe and the pipe rack fixing hole are shown separately. The pipe rack is made of seamless steel pipes with a specification of 40mm×6mm×3000mm. The circumferential spacing of the pipe rack is 500mm, and an upward inclination angle of 2° to 4° is used during installation. A drill hole is opened at the end of the steel pipe, and a grouting hole is set at one end for injecting slurry.

[0045] Figure 3 This is a schematic diagram of the design of a pipe shed grouting and curing hole outside the tunnel contour line disclosed in an embodiment of the present application. Specifically, in the cross-sectional layout of an implementation scenario, two rows of pipe sheds are set along the outside of the tunnel contour line (except the bottom), with a total of 49 steel pipes. The outer circle radius is 2.6m, the inner circle radius is 2.4m, and the horizontal distance between adjacent pipe sheds is 0.5m. The grouting pipes on both sides of the top of the arc in the figure are tilted inward at an angle of 45°, the grouting pipes in the middle remain vertically arranged, and the grouting pipes on both sides of the lower part are arranged in an arc shape along the tunnel contour line. The overall pipe shed arrangement forms an arch structure, and the double rows of pipe sheds are symmetrically distributed to form a continuous support system. Grouting holes are opened on the surface of the steel pipe at a specific interval for uniform injection of slurry during the grouting process.

[0046] Figure 4A schematic diagram of a gas extraction drilling arrangement disclosed in an embodiment of the present application. In terms of spatial position, the system forms a three-dimensional extraction network through the 1806 auxiliary transport lane, the front of the main transport lane, and the right connecting lane. The 1806 auxiliary transport lane is located at the top of the system and is adjacent to the front of the main transport lane. In the entire area, the fault group area and the coal seam group area are located in the upper and lower parts of the pre-extraction area, respectively, constituting the main target area for gas extraction.

[0047] The drilling arrangement adopts a multi-level and multi-directional design. Top intercepting holes for pre-extraction into the tunnel are set up in the top area, and the arrangement of these drilling holes extends more than 15 meters outside the grouting solidification area. The intercepting holes are divided into two categories: one is to use part of the original gas extraction holes, and the other is the newly added gas extraction holes. The arrangement of these drilling holes includes both through-layer drilling and along-layer drilling, forming a complete three-dimensional extraction network.

[0048] A series of interception and extraction holes are arranged between the fault group section area and the coal seam group area. The purpose of these holes is to prevent the accumulation of isolated gas in the grouting solidification area. The directional design of the holes ensures effective coverage of the entire target area. At the same time, through the reasonable hole spacing and angle arrangement, a systematic pre-interception and extraction protection zone is formed. The pre-extraction direction is consistent with the tunnel excavation direction, ensuring the advanced pre-extraction effect.

[0049] In summary, the embodiment of the present application discloses a comprehensive coal-explosion prevention technology of "grouting-solidification-interception and extraction" for deep mine tunnels with complex geological conditions where large fault groups and coal seam groups coexist. On the basis of the advance support of pipe-roof grouting reinforcement and the full-section grouting reinforcement for the tunnel head, the gas isolated after grouting and solidification is quickly extracted from this area by using the inter-layer and inter-layer interception and extraction holes, thereby improving the safe and rapid tunneling process. At the same time, a technical system for coal-explosion prevention in tunnels in the broken areas of fault groups and coal seam groups is formed, which solves the problems of slow construction speed, serious roof collapse and spalling, high tunnel repair rate, high gas pressure and content in mine tunnels where fault groups and coal seam groups coexist, shortens the excavation construction time, reduces construction costs, creates economic benefits, and improves labor efficiency, ensuring the safe and rapid construction of tunnels through fault groups and coal seam groups.

[0050] In addition, in one embodiment, before adopting this technology: the maximum residual gas content is 5.0754m 3 / t, original coal seam gas pressure: 1~2Mpa. Measured data after 30 days of using this technology: Maximum residual gas content: 2.5780m 3 / t, the average coal seam gas pressure is 0.15MPa, the maximum is 0.26Mpa, the average K1 value of the drilling cuttings gas desorption index is 0.1906mL / (g·min½), the average drilling amount S value is 1.7063kg / m, and the maximum is 2.2kg / m. These parameters are obviously less than the critical value and meet the requirements of burst prevention.

[0051] Furthermore, an embodiment of the present application also discloses a coal seam gas interception and extraction and outburst prevention control device based on grouting solidification, comprising: a processor, a memory, and a system bus; the processor and the memory are connected via the system bus; the memory is used to store one or more programs, and the one or more programs include instructions, which, when executed by the processor, enable the processor to execute any of the above methods.

[0052] Furthermore, an embodiment of the present application also discloses a computer program product, which, when executed on a terminal device, enables the terminal device to execute any of the above methods.

[0053] It can be known from the description of the above implementation mode that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a storage medium such as ROM / RAM, a disk, an optical disk, etc., including several instructions for enabling a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0054] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0055] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0056] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A coal seam gas interception and extraction method based on grouting solidification, characterized in that: include: Drilling sites are dug on both sides of the tunnel, construction drilling is carried out according to the drilling arrangement parameters, seamless steel pipes are inserted after the rock cuttings are cleaned, and grouting pipes are arranged at preset intervals; Prepare grouting materials to calculate the grouting volume and complete the grouting from top to bottom in accordance with the progressive pressure increase scheme; Full-section grouting holes are arranged in front of the tunnel head, and grouting is carried out in a zoned and layered manner to form two layers of solidification zones; These include: arranging full-section grouting holes within the specified range in front of the tunnel; arranging grouting holes at preset intervals along the tunnel section contour and installing polyethylene pipes; grouting in a zoned and layered manner, dividing the section into three areas: upper, middle and lower; calculating the area of ​​the solidification zone based on the distance from the tunnel contour line to the boundary of the solidification zone, so as to divide each area into two layers of inner and outer solidification zones for grouting; Gas extraction holes are arranged inside and outside the grouting area, and through-layer or along-layer gas extraction holes are arranged through auxiliary transport tunnels and connecting tunnels; The gas drainage holes inside and outside the solidification zone are respectively connected to the drainage pipeline, and continuous drainage is performed within a preset pressure range; including: the drainage is controlled based on a nonlinear equation of gas flow; the nonlinear equation includes: ,in, represents the extraction flow at time t, represents the coal seam permeability, represents the original coal seam pressure, Indicates the negative pressure of extraction. represents the pressure attenuation coefficient, Indicates the dynamic viscosity of gas, is the gas constant, Indicates absolute temperature.

2. The method for intercepting and extracting coal seam gas and preventing outbursts according to claim 1 is characterized in that: in, Drilling sites are dug on both sides of the tunnel, construction drilling is carried out according to the drilling arrangement parameters, seamless steel pipes are inserted after cleaning the rock cuttings, and grouting pipes are arranged at preset intervals, including: An ear drill field is excavated on one or both sides of the tunnel, and the clear cross-section of the ear drill field is not less than the specified size; Determine the number of single-row drill holes and the number of rows of drill holes according to the width and height of the tunnel section; Use a hydraulic crawler drill to drill holes in sequence according to preset spacing and inclination; Use compressed air to clean the rock cuttings in the borehole and insert the seamless steel pipe into the borehole; Grouting pipes are arranged at preset intervals outside the tunnel contour line and are laid out from top to bottom.

3. The method for intercepting and extracting coal seam gas and preventing outbursts according to claim 1 is characterized in that: in, Prepare grouting materials to calculate the grouting volume and complete the grouting from top to bottom according to the progressive pressure increase scheme, including: Ordinary Portland cement is selected as the base material, and the grouting material is prepared according to the preset mass ratio; Calculate the theoretical grouting volume of a single borehole based on the borehole diameter and length; Calculate the required amount of grouting material according to the overflow coefficient; Use a grouting pump to deliver grouting materials through a high-pressure hose; A progressive pressure-increasing scheme is used for grouting, and grouting is completed from top to bottom.

4. The method for intercepting and extracting coal seam gas and preventing outbursts according to claim 1 is characterized in that: in, Gas drainage holes are arranged inside and outside the grouting area, and through-layer or along-layer gas drainage holes are arranged through auxiliary transport tunnels and connecting tunnels, including: Arrange the gas extraction system in the same direction as the grouting holes; Gas drainage holes are arranged inside and outside the grouting area; Within the specified range outside the solidification area, through-layer or along-layer gas extraction boreholes are arranged through adjacent auxiliary transport tunnels and connecting tunnels.

5. The method for intercepting and extracting coal seam gas and preventing outbursts according to claim 1 is characterized in that: in, Connect the gas drainage holes inside and outside the solidification area to the drainage pipelines respectively, and carry out continuous drainage within the preset pressure range, including: Connect the gas drainage hole inside the solidification area to the drainage pipeline; Continuously extract gas from the inner side of the solidification zone; Connect the gas drainage hole outside the solidification area to the drainage pipeline; Continuous extraction of gas outside the solidification zone; Maintain the extraction pressure within the preset range.

6. The method for intercepting and extracting coal seam gas and preventing outbursts according to claim 2 is characterized in that: in, Determine the number of single-row drill holes and rows of drill holes based on the tunnel section width and height, including: , ， in, Indicates the number of holes drilled in a single row. Indicates the width of the tunnel section. Indicates the tunnel section height, Indicates the number of rows of holes drilled, Indicates a round-up operation.

7. The method for intercepting and draining coal seam gas and preventing outbursts according to claim 1 is characterized in that: in, The area of ​​the solidification zone is calculated based on the distance from the tunnel contour to the boundary of the solidification zone, so that each area can be divided into two layers of inner and outer solidification zones for grouting, including: , , in, Represents the theoretical area of ​​the inner solidification zone, Indicates the reference distance from the roadway contour to the boundary of the solidification zone. Represents the theoretical area of ​​the outer solidification zone.

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