Construction method of FRP (Fiber Reinforce Plastic) constrained fly ash geopolymer roadside filling body

Abstract

The invention discloses a construction method of an FRP (Fiber Reinforce Plastic) constrained fly ash geopolymer roadside filling body, which relates to the technical field of coal mining, and comprises the following steps: firstly, preparing a prefabricated FRP pipe, a filling mold bag, a filling material containing fly ash and the like, and a related filling system; after the working face is pushed, preparation work such as top plate supporting is carried out, and then the prefabricated FRP pipe and the filling mold bag are installed to form a to-be-filled pipe column. The fly ash and other materials are stirred by a stirring station to prepare the fly ash-based geopolymer filling material, the filling material is injected into a pipe column filling mold bag, and after filling, an ultra-high molecular weight polyethylene belt is used for winding. And constructing an air leakage prevention wall comprising a metal net, air duct cloth and a reinforcing mesh, and laying a concrete layer to seal the goaf. According to the method, waste such as fly ash is fully utilized, the construction cost is reduced, the thermal damage problem of the high-temperature mine filling body is solved, the bearing capacity of the filling body is improved by means of FRP constraint, the gob-side entry retaining roof supporting effect is guaranteed, the coal resource recovery rate is increased, and coal-pillar-free continuous mining is promoted.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, in particular to a method for constructing an FRP-constrained fly ash geopolymer roadside filling body. Background Art

[0002] The gob-side tunneling method is an important technology to achieve continuous mining without coal pillars, among which high-water-reinforced materials are widely used as the core materials of tunnel side fillings. FRP, or fiber reinforced polymer, is a high-performance material composed of fiber materials and matrix materials, and is widely used in many fields.

[0003] In recent years, people have conducted a lot of research on the FRP material confinement method to improve the strength of concrete materials. Scientific research and field practice show that the strength of the roadside filling body constructed with FRP confinement materials is not only related to the type of filling core material, but also to the material use environment such as temperature. Affected by the mine temperature and the use method of FRP, the strength growth rate of the internal filling material is different, and the overall strength after reaching the peak strength is not ideal. Some core filling materials such as high-water materials will also suffer thermal damage in high temperature environments, resulting in reduced strength and loss of bearing capacity.

[0004] In addition, in order to improve the recovery rate of coal resources, reduce the occupation, consumption and damage of land resources by mining activities, and reduce mining costs, some areas adopt the method of using coal gangue to fill mesh boxes to construct gob-side tunnel protection walls according to local government policies. This method can make full use of coal gangue waste materials, effectively reduce the construction cost of gob-side tunnel protection walls, and in some areas where coal gangue is not required to go up the mine, it can be filled in situ underground, which greatly facilitates the treatment of coal gangue and reduces the treatment cost. However, this method is suitable for gob-side tunnels under high ambient temperature conditions such as high-temperature mines in the eastern region and deep mines in some areas. The coal gangue filling mesh box protection wall is composed of steel wire mesh boxes and coal gangue, and its structural strength is limited. It is necessary to add additional cementitious materials to improve the overall strength. There are often problems such as insufficient support resistance and increased cementitious material costs.

[0005] In summary, the existing technologies related to the construction of roadside filling bodies have their own advantages and limitations in different mining environments. Summary of the invention

[0006] The purpose of the present invention is to provide a method for constructing a FRP-constrained fly ash geopolymer roadside filling body to solve the problems existing in the above-mentioned prior art and improve the safety of the roadside filling body construction process and the strength of the roadside filling body.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] The present invention provides a method for constructing an FRP-constrained fly ash geopolymer roadside filling body, comprising:

[0009] S1. Preparing prefabricated FRP pipes, filling mold bags, filling materials and filling systems, wherein the filling materials include fly ash, slag, alkali activator, coal gangue and crushed stone;

[0010] The filling system is arranged in a mine, and comprises a first mixing station, a first conveying station and a second mixing station. The discharge port of the first mixing station is connected with the feed port of the second mixing station through a slurry pipe. The first conveying station is used to convey materials to the second mixing station. The discharge port of the second mixing station is connected with a filling pipe.

[0011] and transporting the prefabricated FRP pipe, the filling mold bag and the filling material to the filling system;

[0012] S2. After the working face is pushed, high-strength anchor cables are used to timely support the top plate of the area to be filled, and single hydraulic props are used to support the top plate of the area to be filled;

[0013] S3. Clean the top plate and bottom plate of the area to be filled at the construction location to ensure that the top plate and bottom plate of the area to be filled are flat;

[0014] S4, lagging the working surface, installing the prefabricated FRP pipe at a designated position, with the spacing between two adjacent prefabricated FRP pipes being 800 to 1200 mm;

[0015] S5, setting a filling mold bag in each installed prefabricated FRP pipe, so that the prefabricated FRP pipe and the corresponding filling mold bag are combined into a pipe column to be filled;

[0016] S6, putting the fly ash, the slag, the alkali activator and the water into the first mixing station according to the designed proportion, and stirring them for 3 to 5 minutes through the first mixing station to form a fly ash-based slurry, and then conveying the fly ash-based slurry to the second mixing station through the slurry pipe; and conveying the gangue and the crushed stone to the second mixing station through the first conveying station, and adding water to the second mixing station, and then stirring the second mixing station for 5 to 10 minutes, and mixing in the second mixing station to form a fly ash-based polymer filling material;

[0017] S7, filling the fly ash-based polymer filling material in the pipe column to be filled to form an FRP-constrained fly ash-based polymer material column. The filling method of a single pipe column to be filled is as follows:

[0018] (1) connecting the filling pipe to the filling port of the filling mold bag on the pipe column to be filled, and injecting the fly ash-based polymer filling material into the filling mold bag of the pipe column to be filled through the filling pipe;

[0019] (2) continuously injecting the fly ash-based polymer filling material until slurry overflows from the exhaust port of the filling mold bag of the pipe column to be filled;

[0020] (3) using a wet-wrapping method to wrap an ultra-high molecular weight polyethylene tape around the top of the prefabricated FRP pipe of the pipe column to be filled with the fly ash-based polymer filling material;

[0021] S8, constructing a leak-proof wind wall along the side of the FRP-constrained fly ash-based polymer material column close to the goaf, and laying a concrete layer on the side of the leak-proof wind wall close to the tunnel to seal the goaf, and after the concrete layer solidifies for 24 hours, remove the single hydraulic prop;

[0022] S9. Repeat steps S2-S8 until mining is completed, and after filling is completed, clean the filling system.

[0023] Preferably, the filling mold bag is a cylindrical bag body made of polyvinyl chloride waterproof coiled material, the diameter of the filling mold bag is equal to the inner diameter of the prefabricated FRP pipe, the height of the filling mold bag is 5% greater than the height of the lane, and the filling port and the exhaust port are both arranged at the top of the filling mold bag;

[0024] The alkaline activator is prepared by mixing a sodium hydroxide solution with a concentration of 30% and a water glass solution with a concentration of 1.5 mol / L according to a set ratio.

[0025] Preferably, the particle size of the coal gangue and the particle size of the crushed stone are both less than 100 mm.

[0026] Preferably, the ultra-high molecular weight polyethylene tape is cut from ultra-high molecular weight polyethylene fiber cloth sheets, the number of layers of the ultra-high molecular weight polyethylene tape is the same as the number of layers of FRP material in the prefabricated FRP tube, the length of the circumferential overlap area between the ultra-high molecular weight polyethylene tape and the prefabricated FRP tube is not less than 1 / 3 of the circumference of the cross-sectional area of ​​the prefabricated FRP tube, and the length of the axial overlap area between the ultra-high molecular weight polyethylene tape and the prefabricated FRP tube is not less than 100 mm.

[0027] Preferably, the wind leakage prevention wall includes a layer of metal mesh, a layer of air duct cloth and a layer of steel mesh, and the metal mesh is located on the tunnel side of the wind leakage prevention wall, and the steel mesh is located on the goaf side of the steel mesh; the air duct cloth is sandwiched between the metal mesh and the steel mesh.

[0028] Preferably, for non-high-temperature mines, after performing step S7 and before performing step S8, a heating device is used to perform high-temperature heating on the newly formed FRP-constrained fly ash-based polymer material column. The heating time is 12 hours, and the heating temperature is 45°C to 55°C. The heating device uses an electric heating blanket for building concrete maintenance.

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

[0030] The strength and bearing capacity of the filling body constructed by the FRP-constrained fly ash geopolymer roadside filling body construction method of the present invention utilizes the constraints provided by the fiber composite material (FRP) to significantly enhance the ultimate bearing capacity and axial deformation capacity of the fly ash-based polymer material. As a high-performance material, the combination of FRP and the filling material can strengthen the filling body in structure and effectively improve the bearing performance of the filling body when subjected to external forces such as roadway roof pressure.

[0031] Furthermore, the anti-leakage wind wall in the present invention includes a metal mesh, a wind tube cloth and a steel mesh, and each layer has a specific position layout, the metal mesh is located on the tunnel side of the anti-leakage wind wall, the steel mesh is located on the goaf side, and the wind tube cloth is sandwiched between the metal mesh and the steel mesh. This multi-layer structure design enables each layer of material to work together to form a more rigorous protection system, effectively blocking the air circulation between the goaf and the roadway, and achieving a sealing effect on the goaf.

[0032] The metal mesh can play a preliminary blocking and supporting role, preventing the passage of larger particles, and at the same time provide a certain structural strength support for the entire anti-leakage wind wall; the air duct cloth has good flexibility and sealing, and can fill the tiny gaps that may exist between the layers of materials, further enhancing the sealing performance of the anti-leakage wind wall; the steel mesh on the goaf side can enhance the anti-leakage wind wall's impact resistance facing the goaf side, preventing some geological activities or pressure changes that may occur inside the goaf from damaging the anti-leakage wind wall, thereby ensuring the sustainability of its sealing effect. The setting of the anti-leakage wind wall creates a relatively stable environment for the filling body and surrounding related facilities (such as single hydraulic pillars, etc.) beside the lane. Because it can effectively block the air flow and possible material exchange between the goaf and the lane, it avoids the influence of some unstable factors in the goaf (such as air flow impact, dust diffusion, etc.) on the filling body and surrounding facilities, which helps to maintain the structural integrity and performance stability of the filling body and extend the service life of the filling body and related facilities. For example, while waiting for the concrete layer to solidify, the anti-leakage wind wall can prevent external factors from interfering with the normal solidification process of the concrete layer, ensuring that the concrete layer can achieve the expected strength and performance, thereby better playing its role in the entire tunnel side filling construction system.

[0033] Furthermore, when constructing the tunnel side filling body of the present invention, the filling materials selected include fly ash, slag, alkali activator, coal gangue and crushed stone. Most of these materials are wastes or by-products in the industrial production process. For example, fly ash is the product of coal combustion, and coal gangue is the associated waste in the coal mining process. By using these wastes as the main components of the filling body, the resource utilization of wastes is fully realized, the pressure of waste discharge on the environment is reduced, and good environmental benefits are achieved. Since a large amount of these wastes that originally needed to be processed or disposed of are used as filling materials, the construction cost of the tunnel side filling body is greatly reduced. Compared with the traditional use of some specific and relatively expensive filling materials, the material selection method of the present invention has significant advantages in cost control, which can effectively save production costs and improve economic benefits for coal mining companies.

[0034] Furthermore, in the prior art, some core filling materials such as high-water materials will suffer thermal damage in high-temperature environments, which will lead to reduced strength and loss of bearing capacity. This poses a serious threat to the stability and safety of the side filling bodies in high-temperature mines, and affects the effective implementation of the method of retaining tunnels along the goaf. The present invention adopts fly ash-based polymer filling materials. Compared with traditional materials that are easily damaged by heat (such as high-water materials), this material has the characteristics of fast hardening and early strength in high-temperature environments, and can effectively resist the adverse effects of high-temperature environments on the strength of the filling body. It solves the problem of thermal damage to the core materials of the filling body in high-temperature mines, ensures the strength and stability of the filling body under high-temperature conditions, and thus ensures the safety and reliability of the tunnels along the goaf.

[0035] Furthermore, the ultimate bearing capacity and axial deformation capacity of fly ash-based polymer materials are significantly enhanced by the constraints provided by fiber reinforced plastics (FRP). As a high-performance material, FRP combined with filling materials can strengthen the filling body in structure and effectively improve the bearing performance of the filling body when subjected to external forces such as tunnel roof pressure.

[0036] Furthermore, by making FRP tubes by alternating winding at specific angles, the ultimate bearing capacity and axial deformation capacity of the FRP-constrained fly ash-based polymer material column can be further improved. This special manufacturing method optimizes the structural performance of the FRP tube, enabling it to work better with the filling material, providing stronger support and restraint for the filling body, and further improving the overall mechanical properties of the filling body.

[0037] Furthermore, the use of the present invention to construct the side filling body of the goaf-retained lane can ensure the support effect of the roof rock layer along the goaf-retained lane. Through a series of reasonable construction steps, such as using high-strength anchor cables to timely support the roof of the area to be filled, using single hydraulic pillars to support the roof of the area to be filled, etc., combined with the good mechanical properties of the filling body itself, the roof rock layer can be stably and effectively supported, reducing the risk of safety accidents such as roof collapse, and ensuring the normal use and safe production of the lane. Not only does it effectively reduce the construction cost of the side filling body of the goaf-retained lane, it also solves the problem of thermal damage to the core filling material in a high-temperature environment, realizes continuous mining without coal pillars, and effectively improves the recovery rate of coal resources. This series of technical effects combined make the present invention have important application value in the field of coal mining, which not only meets the needs of enterprises to reduce costs and improve production efficiency, but also takes into account the requirements of environmental protection and effective utilization of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 It is a structural schematic diagram of an FRP-constrained fly ash-based polymer material column in the FRP-constrained fly ash geopolymer roadside filling body construction method of the present invention;

[0040] Figure 2 It is a schematic diagram of a part of the structure of the prefabricated FRP pipe in the method for constructing the FRP-constrained fly ash geopolymer roadside filling body of the present invention;

[0041] Figure 3 It is a top view of the construction of the FRP-constrained fly ash geopolymer roadside filling body construction method of the present invention;

[0042] Figure 4 The construction side view of the method for constructing the FRP-constrained fly ash geopolymer roadside filling body of the present invention Figure 1 ;

[0043] Figure 5 The construction side view of the method for constructing the FRP-constrained fly ash geopolymer roadside filling body of the present invention Figure 2 ;

[0044] Figure 6 It is a structural schematic diagram of a heating device in the method for constructing a FRP-constrained fly ash geopolymer roadside filling body of the present invention;

[0045] Figure 7It is a partial structural schematic diagram of the heating equipment in the method for constructing the FRP-constrained fly ash geopolymer roadside filling body of the present invention;

[0046] Figure 8 is a stress curve diagram of a uniaxial compression test of fly ash-based polymer filling material A;

[0047] Fig. 9 is a stress curve diagram of a uniaxial compression test of fly ash-based polymer filling material B;

[0048] In the figure: 1. Prefabricated FRP pipe; 2. Fly ash-based polymer filling material; 3. Filling mold bag; 4. Exhaust port; 5. Filling port; 6. Ultra-high molecular weight polyethylene tape; 7. Pipe wall; 8. FRP constraint wrapped at an angle of 80 degrees; 9. FRP constraint wrapped at an angle of 60 degrees; 10. First mixing station; 11. Slurry pipe; 12. First conveying station; 13. Water pipe; 14. Second mixing station; 15. Filling pipe; 16. High-strength anchor cable; 17. Monomer hydraulic support; 18. Pipe column to be filled; 19. FRP-constrained fly ash-based polymer material column; 20. Anti-leakage wind wall; 21. Goaf; 22. Coal body; 23. Working face; 24. Hydraulic support; 25. Roof of the area to be filled; 26. Heating equipment; 27. Heating part; 28. Controller; 29. ​​Power supply part. DETAILED DESCRIPTION

[0049] 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.

[0050] The purpose of the present invention is to provide a method for constructing a FRP-constrained fly ash geopolymer roadside filling body to solve the problems existing in the above-mentioned prior art and improve the safety of the roadside filling body construction process and the strength of the roadside filling body.

[0051] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] like Figures 1 to 7 As shown, this embodiment provides a method for constructing a FRP-constrained fly ash geopolymer roadside filling body, comprising:

[0053] S1, preparing prefabricated FRP pipe 1, filling mold bag 3, filling materials and filling system, the filling materials include fly ash, slag, alkali activator, coal gangue and crushed stone;

[0054] The filling system is arranged in the mine, and includes a first mixing station 10, a first conveying station 12 and a second mixing station 14. The discharge port of the first mixing station 10 is connected with the feed port of the second mixing station 14 through a slurry pipe 11. The first conveying station 12 is used to convey the material to the second mixing station 14. The discharge port of the second mixing station 14 is connected with a filling pipe 15.

[0055] The prefabricated FRP pipe 1, the filling mold bag 3 and the filling materials are all transported to the filling system;

[0056] S2. After the working face 23 is pushed, the top plate 25 of the area to be filled is supported in time by using high-strength anchor cables 16, and the top plate 25 of the area to be filled is supported by using single hydraulic props 17;

[0057] S3, cleaning the top plate 25 and the bottom plate of the area to be filled at the construction position to ensure that the top plate 25 and the bottom plate of the area to be filled are flat;

[0058] S4. During the mining process, the roof is supported by the hydraulic support 24, the working surface 23 of the coal body 22 is lagged behind, and the prefabricated FRP pipes 1 are installed at the designated position, and the distance between two adjacent prefabricated FRP pipes 1 is 800-1200 mm;

[0059] It is worth noting that the above-mentioned designated position refers to the area between the rear of the working face hydraulic support 24 and the single hydraulic support 17, and the specific setting position needs to be determined by the staff according to the on-site conditions;

[0060] S5, setting a filling mold bag 3 in each installed prefabricated FRP tube 1, so that the prefabricated FRP tube 1 and the corresponding filling mold bag 3 are combined into a pipe column 18 to be filled;

[0061] S6, fly ash, slag, alkali activator and water are placed in the first mixing station 10 according to the designed proportion, and stirred for 3 to 5 minutes by the first mixing station 10 to form fly ash-based slurry, and then the fly ash-based slurry is transported to the second mixing station 14 through the slurry pipe 11; and the gangue and crushed stone are transported to the second mixing station 14 through the first conveying station 12, and water is added to the second mixing station 14 through the water pipe 13, and then the second mixing station 14 is stirred for 5 to 10 minutes, and the fly ash-based polymer filling material 2 is formed in the second mixing station;

[0062] S7, filling the fly ash-based polymer filling material 2 in the pipe column 18 to be filled to form an FRP-constrained fly ash-based polymer material column 19. The filling method of a single pipe column 18 to be filled is as follows:

[0063] (1) Connect the filling pipe 15 to the filling port 5 of the filling mold bag 3 on the pipe column 18 to be filled, and inject the fly ash-based polymer filling material 2 into the filling mold bag 3 of the pipe column 18 to be filled through the filling pipe 15;

[0064] (2) continuously injecting the fly ash-based polymer filling material 2 until slurry overflows from the exhaust port 4 of the filling mold bag 3 of the pipe column 18 to be filled;

[0065] (3) using a wet-wrapping method to wrap an ultra-high molecular weight polyethylene tape 6 around the top of a prefabricated FRP pipe 1 of a pipe column 18 to be filled with a fly ash-based polymer filling material 2;

[0066] S8, constructing a leak-proof wind wall 20 along the side of the FRP-constrained fly ash-based polymer material column 19 close to the goaf 21, and laying a concrete layer on the side of the leak-proof wind wall 20 close to the tunnel to seal the goaf 21, waiting for the concrete layer to solidify for 24 hours, and then removing the single hydraulic support 17;

[0067] S9. Repeat steps S2-S8 until mining is completed, and after filling is completed, clean the filling system.

[0068] In this embodiment, in step S6, the mass ratio of fly ash, slag, alkali activator and water put into the first mixing station 10 is 20:20:7:3 to 22:22:8:2.

[0069] In this embodiment, the prefabricated FRP pipe 1 can be made of carbon fiber materials such as carbon fiber, glass fiber, basalt fiber, polyethylene fiber, ultra-high molecular weight polyethylene fiber, etc., and is prefabricated into a cylindrical shell on the ground of the mine by wet laying. The height of the prefabricated FRP pipe 1 is 5% less than the height of the tunnel. The wall thickness and diameter of the prefabricated FRP pipe 1 are determined by the geomechanical characteristics of the surrounding rock of the gob-side tunnel and the support strength of the gob-side tunnel. The prefabricated FRP pipe 1 is made by alternating winding, and the alternating winding angles are 60° and 80° respectively. If the required support strength is large, the alternating fiber winding angle can be appropriately increased. Figure 2 As shown, the tube wall 7 of the prefabricated FRP tube 1 includes an FRP constraint 8 wound at an angle of 80 degrees and an FRP constraint 9 wound at an angle of 60 degrees.

[0070] In the optional scheme of this embodiment, it is more preferred that the filling mold bag 3 is a cylindrical bag body made of polyvinyl chloride waterproof coiled material, the diameter of the filling mold bag 3 is equal to the inner diameter of the prefabricated FRP pipe 1, the height of the filling mold bag 3 is 5% greater than the height of the lane, and the filling port 5 and the exhaust port 4 are both arranged at the top of the filling mold bag 3;

[0071] The alkaline activator is formed by mixing a sodium hydroxide solution with a concentration of 30% and a water glass solution with a concentration of 1.5 mol / L according to a set ratio. In this embodiment, the mass ratio of the sodium hydroxide solution to the water glass solution is 2:2.3; the alkaline activator can utilize alkaline wastewater or waste alkali liquid generated by chemical, petroleum, pharmaceutical and other industries. The pH value of the waste liquid is required to be not less than 13. If it contains trace amounts of toxic and harmful substances such as heavy metals, it needs to be simply treated to meet the standards before use.

[0072] In this embodiment, the fly ash shall not be lower than the secondary ash standard, and the mass of fly ash particles with a particle size less than 100 μm exceeds 80% of the total mass.

[0073] In the optional scheme of this embodiment, it is more preferred that the particle size of the coal gangue, the particle size of the slag and the particle size of the crushed stone are all less than 100 mm.

[0074] It is worth noting that the fly ash material mass concentration in the fly ash-based slurry is controlled between 74% and 75%, the mass proportion of slag is 40%, the mass concentration of alkali activator material is controlled between 25% and 26%, the concentration of alkali activator itself is controlled at about 30%, and the water-binder ratio is controlled at about 0.5. Coal gangue and gravel need to be fully infiltrated in advance, and the water-binder ratio is less than 0.5.

[0075] In the optional scheme of the present embodiment, it is more preferred that the ultra-high molecular weight polyethylene tape 6 is cut from ultra-high molecular weight polyethylene fiber cloth sheets, the number of layers of the ultra-high molecular weight polyethylene tape 6 is the same as the number of layers of the FRP material in the prefabricated FRP tube 1, the length of the circumferential overlap area between the ultra-high molecular weight polyethylene tape 6 and the prefabricated FRP tube 1 is not less than 1 / 3 of the circumference of the cross-sectional area of ​​the prefabricated FRP tube 1, and the length of the axial overlap area between the ultra-high molecular weight polyethylene tape 6 and the prefabricated FRP tube 1 is not less than 100 mm.

[0076] In the optional scheme of this embodiment, it is more preferred that the anti-leakage wind wall 20 includes a layer of metal mesh, a layer of wind tube cloth and a layer of steel mesh, and the metal mesh is located on the tunnel side of the anti-leakage wind wall 20, and the steel mesh is located on the goaf 21 side of the steel mesh; the wind tube cloth is sandwiched between the metal mesh and the steel mesh.

[0077] In a specific application, for non-high temperature mines, after step S7 and before step S8, the newly formed FRP-constrained fly ash-based polymer material column 19 is heated at high temperature using a heating device 26, the heating time is 12 hours, and the heating temperature is 45° C. to 55° C. The heating device 26 uses a building concrete curing electric heating blanket, which is usually composed of a heating part 27, a controller 28, and a power supply part 29, and wraps the roadside filling body for high temperature heating.

[0078] In addition, the applicant conducted sufficient experiments on fly ash-based polymer filling materials, and prepared fly ash-based polymer filling materials with two material ratios A and B. The specific material ratios (mass ratios) are as follows:

[0079]

[0080] The aggregates in the above table are coal gangue, crushed stone or slag.

[0081] The results of the uniaxial compression test of fly ash-based polymer filling material A are as follows: Figure 8 As shown in Figure 2, the results of the uniaxial compression test of fly ash-based polymer filling material B are as follows: Fig. 9 As shown, the test results show that the compressive strength of the fly ash-based polymer filling material in this embodiment can fully meet the use requirements.

[0082] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for constructing a FRP-constrained fly ash geopolymer roadside filling, characterized in that: include: S1. Preparing prefabricated FRP pipes, filling mold bags, filling materials and filling systems, wherein the filling materials include fly ash, slag, alkali activator, coal gangue and crushed stone; The filling system is arranged in a mine, and comprises a first mixing station, a first conveying station and a second mixing station. The discharge port of the first mixing station is connected with the feed port of the second mixing station through a slurry pipe. The first conveying station is used to convey materials to the second mixing station. The discharge port of the second mixing station is connected with a filling pipe. and transporting the prefabricated FRP pipe, the filling mold bag and the filling material to the filling system; S2. After the working face is pushed, high-strength anchor cables are used to timely support the top plate of the area to be filled, and single hydraulic props are used to support the top plate of the area to be filled; S3. Clean the top plate and bottom plate of the area to be filled at the construction location to ensure that the top plate and bottom plate of the area to be filled are flat; S4, lagging the working surface, installing the prefabricated FRP pipe at a designated position, with the spacing between two adjacent prefabricated FRP pipes being 800 to 1200 mm; S5, setting a filling mold bag in each installed prefabricated FRP pipe, so that the prefabricated FRP pipe and the corresponding filling mold bag are combined into a pipe column to be filled; S6, putting the fly ash, the slag, the alkali activator and the water into the first mixing station according to the designed proportion, and stirring them for 3 to 5 minutes through the first mixing station to form a fly ash-based slurry, and then conveying the fly ash-based slurry to the second mixing station through the slurry pipe; and conveying the gangue and the crushed stone to the second mixing station through the first conveying station, and adding water to the second mixing station, and then stirring the second mixing station for 5 to 10 minutes, and mixing in the second mixing station to form a fly ash-based polymer filling material; S7, filling the fly ash-based polymer filling material in the pipe column to be filled to form an FRP-constrained fly ash-based polymer material column. The filling method of a single pipe column to be filled is as follows: (1) connecting the filling pipe to the filling port of the filling mold bag on the pipe column to be filled, and injecting the fly ash-based polymer filling material into the filling mold bag of the pipe column to be filled through the filling pipe; (2) continuously injecting the fly ash-based polymer filling material until slurry overflows from the exhaust port of the filling mold bag of the pipe column to be filled; (3) using a wet-wrapping method to wrap an ultra-high molecular weight polyethylene tape around the top of the prefabricated FRP pipe of the pipe column to be filled with the fly ash-based polymer filling material; S8, constructing a leak-proof wind wall along the side of the FRP-constrained fly ash-based polymer material column close to the goaf, and laying a concrete layer on the side of the leak-proof wind wall close to the tunnel to seal the goaf, and after the concrete layer solidifies for 24 hours, remove the single hydraulic prop; S9. Repeat steps S2-S8 until mining is completed, and after filling is completed, clean the filling system.

2. The method for constructing a FRP-constrained fly ash geopolymer roadside filling according to claim 1, characterized in that: The filling mold bag is a cylindrical bag body made of polyvinyl chloride waterproof coiled material, the diameter of the filling mold bag is equal to the inner diameter of the prefabricated FRP pipe, the height of the filling mold bag is 5% greater than the height of the lane, and the filling port and the exhaust port are both arranged at the top of the filling mold bag; The alkaline activator is prepared by mixing a sodium hydroxide solution with a concentration of 30% and a water glass solution with a concentration of 1.5 mol / L according to a set ratio.

3. The method for constructing a FRP-constrained fly ash geopolymer roadside filling according to claim 1, characterized in that: The particle size of the coal gangue and the particle size of the crushed stone are both less than 100 mm.

4. The method for constructing a FRP-constrained fly ash geopolymer roadside filling body according to claim 1, characterized in that: The ultra-high molecular weight polyethylene tape is cut from ultra-high molecular weight polyethylene fiber cloth sheets, the number of layers of the ultra-high molecular weight polyethylene tape is the same as the number of layers of FRP material in the prefabricated FRP pipe, the length of the circumferential overlap area between the ultra-high molecular weight polyethylene tape and the prefabricated FRP pipe is not less than 1 / 3 of the circumference of the cross-sectional area of ​​the prefabricated FRP pipe, and the length of the axial overlap area between the ultra-high molecular weight polyethylene tape and the prefabricated FRP pipe is not less than 100 mm.

5. The method for constructing a FRP-constrained fly ash geopolymer roadside filling body according to claim 1, characterized in that: The anti-leakage wind wall includes a layer of metal mesh, a layer of air duct cloth and a layer of steel mesh, and the metal mesh is located on the tunnel side of the anti-leakage wind wall, and the steel mesh is located on the goaf side of the steel mesh; the air duct cloth is sandwiched between the metal mesh and the steel mesh.

6. The method for constructing a FRP-constrained fly ash geopolymer roadside filling according to claim 1, characterized in that: For non-high-temperature mines, after step S7 and before step S8, a heating device is used to heat the newly formed FRP-constrained fly ash-based polymer material column at high temperature. The heating time is 12 hours, and the heating temperature is 45°C to 55°C. The heating device uses an electric heating blanket for building concrete maintenance.

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