Long-wall coal face collapse column instability evaluation and comprehensive prevention and control method

Abstract

The invention relates to the technical field of coal mining, and provides a long-wall coal face collapse column instability evaluation and comprehensive prevention and control method. According to the method, based on different preset instability models, instability judgment is carried out on collapse columns of different risk types, and instability prevention and control are carried out on the collapse columns of the different risk types according to instability judgment results of the collapse columns. Therefore, by analyzing the structural characteristics of the collapse column, the cementing state of the surrounding rock and the stress distribution rule, a possible disaster-causing mechanism is determined, and effective targeted instability prevention and control measures are adopted, so that a scientific basis and reliable technical support are provided for prevention and control of mine pressure disasters, and safe production of a working face is ensured.

Description

Technical Field

[0001] This application relates to the technical field of coal mining, and particularly relates to a method for instability assessment and comprehensive prevention and control of collapse columns in longwall coal mining faces. Background Art

[0002] In some mining areas, collapse columns develop from the ground surface to the coal seam, with large scales and having a certain traction effect on the surrounding underlying structures. When the longwall face advances through a collapse column, in order to reduce the frequency of face relocation and improve the production efficiency of the face, sometimes it is necessary to directly cut and mine large collapse columns; however, this may cause serious safety problems.

[0003] When the cementation degree of the collapse column is relatively high, the column body may slide as a whole under the action of its own gravity during the cutting process, or undergo overall rotation and inclination under the influence of the clamping force of the overlying rock; when there are developed fissures or large-scale continuous structural planes in the collapse column, the cutting and the resulting mining-induced stress may cause local sliding or cutting of the column body. Whether the column body slides as a whole under the action of its own gravity, or undergoes overall rotation and inclination under the influence of the clamping force of the overlying rock, or the mining-induced stress causes local sliding or cutting of the column body, all may cause mine pressure problems, such as crushing of the face supports and roof caving near the collapse column, seriously threatening the safety of the face.

[0004] Therefore, there is an urgent need to provide a technical solution to address the deficiencies of the above-mentioned existing technologies. Summary of the Invention

[0005] The purpose of this application is to provide a method for instability assessment and comprehensive prevention and control of collapse columns in longwall coal mining faces to solve or alleviate the problems existing in the above-mentioned existing technologies.

[0006] To achieve the above purpose, this application provides the following technical solutions:

[0007] This application provides a method for instability assessment and comprehensive prevention and control of collapse columns in longwall coal mining faces, including: Step S101, based on preset different instability models, determining the instability of collapse columns of different risk types; Step S102, according to the instability determination results of the collapse columns, carrying out instability prevention and control on the collapse columns of different risk types.

[0008] Preferably, in Step S101, according to the instability model:

[0009] ρgV>2cH(L H +L h )+2μH(σ h ·L h +σ H ·L H )

[0010] Determine the overall sliding instability after the activation of a complete sunken column; where ρ is the rock mass density of the sunken column, g is the acceleration due to gravity, V is the volume of the sunken column, c is the cohesion of the contact surface between the sunken column and the rock mass, H is the height of the sunken column above the coal seam level, and L H is the axial length of the sunken column perpendicular to the maximum horizontal principal stress σ H ; and L h is the axial length of the sunken column perpendicular to the minimum horizontal principal stress σ h ; and μ is the friction coefficient of the contact surface between the sunken column and the rock mass.

[0011] Preferably, in step S101, according to the instability model:

[0012] ρgV > ∫ A (2c·dA + 2μσ·dA)

[0013] Determine the instability of the sunken column with a penetrating main weak surface; where ρ is the rock mass density of the sunken column, g is the acceleration due to gravity, V is the volume of the sunken column, c is the cohesion of the contact surface between the sunken column and the rock mass, μ is the friction coefficient of the contact surface between the sunken column and the rock mass, A is the contact area of the contact surface between the sunken column and the rock mass, and σ is the extrusion normal stress received by the sunken column.

[0014] Preferably, in step S101, according to the instability model:

[0015]

[0016] Determine the instability of the risk of rotary pressure frame of the sunken column; where F max is the maximum support force of the hydraulic support corresponding to the sunken column; ρ is the rock mass density of the sunken column, g is the acceleration due to gravity, V is the volume of the sunken column, and L h is the axial length of the sunken column perpendicular to the minimum horizontal principal stress, and L 支 is the distance between the hydraulic support and the coal wall of the working face, θ is the rotary angle of the overlying strata of the working face, E i is the elastic modulus of the i-th overlying stratum, and h i is the thickness of the i-th overlying stratum.

[0017] Preferably, in step S102, in response to the overall sliding or angular rotation of the sunken column, blast in the goaf behind the sunken column to increase the volume of gangue caving and the swelling coefficient, and / or perform belt filling under the sunken column to support the sunken column.

[0018] Preferably, in step S102, the blasting in the goaf behind the subsidence column to increase the caving volume and swelling coefficient of gangue includes: arranging deep-hole drill holes in a grid pattern in the goaf behind the subsidence column, loading explosives in the deep-hole drill holes and detonating them in batches to induce the caving of the roof strata; controlling the blasting parameters so that the swelling coefficient of the caved gangue is controlled above 1.2, so that the caved gangue fills the pores in the goaf.

[0019] Preferably, in step S102, the belt filling under the subsidence column to support the subsidence column includes: arranging strip-shaped cement wall pairs in the goaf under the subsidence column, and filling the area between the cement wall pairs with waste gangue generated during the coal mining process, and the filling process is synchronized with the advancement of the coal mining face to form a strip-shaped continuous support body; wherein, the swelling coefficient of the waste gangue is above 1.2.

[0020] Preferably, in response to the strip width is 10 meters; in response to the strip width is 15 - 20 meters; in response to the strip width is 30 meters; in response to the strip width is 50 meters.

[0021] Beneficial effects:

[0022] In the longwall coal mining face subsidence column instability evaluation and comprehensive prevention and control method provided by the embodiments of the present application, based on preset different instability models, the instability of subsidence columns of different risk types is determined, and according to the instability determination results of the subsidence columns, the instability prevention and control of subsidence columns of different risk types are carried out. Therefore, by analyzing the structural characteristics, surrounding rock cementation state and stress distribution law of the subsidence column, the possible disaster-causing mechanism is clarified, and effective targeted instability prevention and control measures are taken, providing a scientific basis and reliable technical support for preventing and controlling mine pressure disasters, and ensuring the safe production of the working face. Description of the drawings

[0023] The specification drawings forming a part of the present application are used to provide a further understanding of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application.

[0024] Wherein:

[0025] Figure 1 is a schematic flow chart of a longwall coal mining face subsidence column instability evaluation and comprehensive prevention and control method provided by some embodiments of the present application;

[0026] Figure 2 is a schematic diagram of the column body rotation when the working face passes through the subsidence column provided by some embodiments of the present application;

[0027] Figure 3 Displacement schematic diagram of the contact point of the i-th overlying rock layer during the rotation of the karst collapse column provided according to some embodiments of the present application. Detailed implementation manners

[0028] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present application rather than limiting the present application. In fact, those skilled in the art will clearly understand that modifications and variations can be made to the present application without departing from the scope or spirit of the present application. For example, features shown or described as part of one embodiment can be used in another embodiment to yield yet another embodiment. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention shall fall within the scope of protection of the embodiments of the present invention.

[0029] When the longwall face is pushed and mined through the karst collapse column, it is necessary to comprehensively evaluate the risks such as the sliding and local cutting off of the karst collapse column rock mass, and propose a scientific control plan. Based on this, the embodiments of the present application propose a method for instability assessment and comprehensive prevention and control of karst collapse columns in longwall coal mining faces. By analyzing the structural characteristics, surrounding rock cementation state and stress distribution law of the karst collapse column, the possible disaster-causing mechanisms can be clarified, which can provide a scientific basis and reliable technical support for preventing and controlling mine pressure disasters and ensure the safe production of the working face.

[0030] As Figures 1 to 3 shown, the method for instability assessment and comprehensive prevention and control of karst collapse columns in longwall coal mining faces includes:

[0031] Step S101: Based on preset different instability models, perform instability determination on karst collapse columns of different risk types.

[0032] When the karst collapse column in the longwall coal mining face is about to be cut through, except for the support force of the support (hydraulic support), there is almost no support force at the bottom of the karst collapse column. Whether the karst collapse column is unstable depends on the cohesion and friction force on the contact surface between its own weight and the surrounding rock mass. At this time, the karst collapse column often slides. That is to say, when the gravity of the karst collapse column is greater than the resultant force of the cohesion and friction force on the contact surface (composed of the influence of contact surface friction, cohesion and principal stress), the karst collapse column will slide or become unstable.

[0033] Therefore, for a well-cemented karst collapse column (judging the cementation degree of the karst collapse column by taking cores from geological boreholes), after activation (the stable state is destroyed), according to the instability model:

[0034] ρgV>2cH(L H +L h )+2μH(σ h ·L h +σ H ·L H )

[0035] Determine whether the complete collapse column has the risk of overall sliding instability. In the formula, ρ is the rock mass density of the collapse column, which can be determined by laboratory measurement after on-site dispersive sampling; g is the acceleration due to gravity, V is the volume of the collapse column, which can be calculated after determining the geometric shape of the collapse column through on-site geological drilling; c is the cohesion of the contact surface between the collapse column and the rock mass, which can be determined by direct shear test after taking combined samples of the collapse column and adjacent rock layers on-site; H is the height of the collapse column above the coal seam level; L H is the axial length of the collapse column perpendicular to the maximum horizontal principal stress σ H ; L h is the axial length of the collapse column perpendicular to the minimum horizontal principal stress σ h ; μ is the friction coefficient of the contact surface between the collapse column and the rock mass, which can be determined by direct shear test after taking combined samples of the collapse column and adjacent rock layers on-site; the maximum horizontal principal stress σ H , the minimum horizontal principal stress σ h can be determined by in-situ stress testing.

[0036] The collapse column is composed of rock mass and has many tiny cracks inside. When there is a continuous main weak surface in the collapse column (the tiny cracks in the collapse column are connected and penetrate through the entire collapse column), the instability risk of the collapse column is more complex and changeable. Especially when it comes to the geometric dimensions of the inclined cylinder, the occurrence of the weak surface, and the direction of the principal stress, after calculating and correcting the cohesion and friction force of the contact surface between the collapse column and the rock mass, according to the instability model:

[0037] ρgV>∫ A (2c·dA + 2μσ·dA)

[0038] Determine the instability of the collapse column with a continuous main weak surface. In the formula, ρ is the rock mass density of the collapse column, g is the acceleration due to gravity, V is the volume of the collapse column, c is the cohesion of the contact surface between the collapse column and the rock mass, μ is the friction coefficient of the contact surface between the collapse column and the rock mass, A is the contact area of the contact surface between the collapse column and the rock mass, and σ is the extrusion normal stress received by the collapse column.

[0039] In the longwall coal mining face, especially when the working face is close to the collapse column, due to the rotation effect of the overlying strata, it may cause the collapse column to rotate under the clamping action of the overlying strata of the working face. The hydraulic support faces the risk of increased pressure caused by the rotation of the collapse column, and further generates the risk of hydraulic support pressing. In this regard, in this application, based on the pressure of the support (hydraulic support) generated by the rotation of the collapse column and the maximum support capacity of the support (hydraulic support), the risk of hydraulic support pressing caused by the rotation of the collapse column is evaluated.

[0040] Because the tensile strength of rock is very small and the tensile strength of the cemented surface is less than that of the rock, the caving column will generate a rotational motion under the cutting action of the mining face. The rotational angle θ caused by the mining of the working face will cause the cemented surface between the caving column and the overlying rock of the support (hydraulic support) to be subjected to tensile force and open into cracks, so that the front contact surface is no longer stressed. Although the caving column and the overlying rock of the support (hydraulic support) have a small amount of sliding, they still remain in contact, that is, there is a force acting on the contact surface.

[0041] The magnitude of the rotational angle θ of the overlying rock of the working face is related to multiple factors, including the parameters of the coal mining face: the mining height h of the working face, the width of the caving column in the advancing direction of the working face, that is, the axial length L of the caving column perpendicular to the minimum horizontal principal stress h , the height h of the caving zone in the goaf m , the swelling coefficient of the caving rock, etc. Specifically, after the overlying rock of the working face rotates, according to the formula:

[0042]

[0043] Determine the rotational angle θ of the overlying rock of the working face.

[0044] The rotated caving column (rotated by an angle θ) remains in a balanced state under the combined action of the support force F of the support 支 , the support force of the coal body in front of the support (F 煤x , F 煤y ) and gravity until the working face is cut again and causes the caving column to rotate further, and the most dangerous state occurs when the working face is about to cut off all the caving columns. Here, define the force of the i-th overlying rock layer on the caving column as F 空i , the thickness of the i-th overlying rock layer as h i , the elastic modulus of the i-th overlying rock layer as E i , the distance between the hydraulic support and the coal wall of the working face as L 支 , and analyze the caving column. The displacement Δs generated at the contact point between the caving column and the i-th overlying rock layer is i :

[0045]

[0046] Then:

[0047]

[0048] Furthermore, there is:

[0049] F 支 ·L 支 +∑F 空i ·(∑h i -L h sinθ)=ρgV·(L h -L 支 )cosθ

[0050] Construct a buckling model based on the support force F of the support 支 and the maximum support force F of the support max :

[0051]

[0052] Conduct a buckling determination on the risk of the rotary pressure frame of the collapse column. In the formula, F max is the maximum support force of the hydraulic support corresponding to the collapse column; ρ is the rock mass density of the collapse column, g is the acceleration due to gravity, V is the volume of the collapse column, L h is the axial length of the collapse column perpendicular to the minimum horizontal principal stress, L 支 is the distance between the hydraulic support and the coal wall of the working face, θ is the rotation angle of the overlying strata of the working face, E i is the elastic modulus of the i-th overlying rock layer, h i is the thickness of the i-th overlying rock layer.

[0053] When F max / F 支 < 1, that is, when the maximum support force of the hydraulic support corresponding to the collapse column is less than the support force F of the support 支 , a pressure frame accident will occur on the working face; when F max / F 支 > 1, that is, when the maximum support force of the hydraulic support corresponding to the collapse column is greater than the support force F of the support 支 , the hydraulic support can successfully cut and push through the collapse column.

[0054] Step S102: According to the buckling determination result of the collapse column, conduct buckling prevention and control on collapse columns of different risk types.

[0055] After the well-cemented collapse column is activated and buckled, the entire collapse column moves (slides as a whole); for the collapse column with a penetrating weak surface, it is divided into an upper part and a lower part by the penetrating weak surface. After buckling, the upper part or the lower part of the collapse column moves and rotates, which may lead to the risk of pressure frame. Whether it is the overall sliding of the collapse column or the angular rotation, in this application, prevention and control measures are taken to increase the supporting effect of the overlying rock in the goaf on the collapse column, and a new support body is constructed under the collapse column to support the collapse column. That is to say, blasting in the goaf behind the collapse column increases the volume of caving gangue and the swelling coefficient, and / or belt filling is carried out under the collapse column to support the collapse column. Furthermore, by blasting in the goaf behind the collapse column to increase the volume of caving gangue and the swelling coefficient, the supporting effect of the caving gangue on the overlying strata is improved, thereby increasing the supporting effect of the overlying rock on the collapse column; by carrying out belt filling under the collapse column to support the collapse column.

[0056] In a specific application scenario, when deep-hole blasting is carried out in the goaf to induce caving, deep-hole drill holes are arranged in a grid pattern in the goaf behind the collapse column. Explosives are loaded into the deep-hole drill holes and detonated in batches to induce the caving of the roof strata. That is to say, deep-hole drill holes are arranged in the goaf behind the collapse column. The spacing between the deep-hole drill holes is 6 - 8 meters, the hole depth is 5 - 10 meters, and they are distributed in a grid pattern. Then, explosives with low impact and high fragmentation (such as emulsion explosives) are loaded into the deep-hole drill holes and detonated in batches to induce the caving of the roof strata. During blasting, the blasting fragment size is qualitatively controlled by adjusting the blasting parameters, so that the swelling coefficient of the caved gangue is controlled above 1.2 (preferably 1.2 - 1.3), enabling the caved gangue to fully fill the pores in the goaf.

[0057] In another specific application scenario, when belt filling is carried out under the collapse column to support the collapse column, strip-shaped cement walls are arranged in the goaf under the collapse column. The width of the wall pair is 10 meters, the wall thickness is 1 meter, the interval between the wall pairs is 30 meters, and the wall material is ordinary cement mortar (mixed with fly ash or slag to reduce costs and enhance strength). Among them, the construction of the cement wall is completed by drilling and grouting or formwork pouring. Each pair of cement walls needs to be flush with the top of the goaf to form a rigid support.

[0058] The area between the cement wall pairs is filled with waste gangue generated during the coal mining process. During the gangue filling process, layered filling and compaction are adopted. The swelling coefficient of the waste gangue is above 1.2 (preferably 1.2 - 1.3), and the filling process is synchronized with the advancement of the coal mining face to form a strip-shaped continuous support body, effectively avoiding the problem of insufficient support caused by filling lag.

[0059] In the embodiments of the present application, the width of the filling strip (strip-shaped continuous support body) is dynamically adjusted according to the risk of rotation and pressure frame of the collapse column. Specifically, when 0.8 < F max / F 支 < 1.0, the strip width is 10 meters; when 0.5 < F max / F 支 ≤ 0.8, the strip width gradually increases within the range of 15 - 20 meters; when 0.3 < F max / F 支 ≤ 0.5, the strip width is 30 meters; when F max / F 支 ≤ 0.3, the strip width is 50 meters. At the same time, stress sensors and displacement monitoring devices are arranged in the strip filling area to monitor the stress and support state of the collapse column in real time, and according to the monitoring data, the strip filling process and the filling material are dynamically adjusted to effectively ensure the stability of the support system.

[0060] Therefore, by analyzing the structural characteristics of the subsidence column, the cementation state of the surrounding rock, and the stress distribution law, the possible disaster-causing mechanisms are identified. Through deep-hole blasting in the goaf to induce caving, strip-shaped cement wall filling, gangue filling, and the monitoring and feedback of stress sensors and displacement monitoring devices, the instability of the subsidence column is prevented and controlled, providing a scientific basis and reliable technical support for preventing and controlling mine pressure disasters and ensuring the safe production of the working face.

[0061] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0062] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0063] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0065] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0066] The foregoing are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A method for evaluating the instability of collapse columns in longwall coal mining faces and comprehensive prevention and control, characterized in that Including: Step S101: Based on preset different instability models, conduct instability determination on collapse columns of different risk types; Step S102: According to the instability determination results of the collapse columns, conduct instability prevention and control on the collapse columns of different risk types.

2. The method for evaluating the instability of the collapse column in the longwall coal mining face and comprehensive prevention and control according to claim 1, characterized in that In step S101, According to the instability model: ρgV > 2cH(L H + L h ) + 2μH(σ h ·L h + σ H ·L H ) Conduct determination on the overall sliding instability after the activation of a complete collapse column; Wherein, ρ is the rock mass density of the collapse column, g is the acceleration due to gravity, V is the volume of the collapse column, c is the cohesion of the contact surface between the collapse column and the rock mass, H is the height of the collapse column above the coal seam level, L H is the axial length of the collapse column perpendicular to the maximum horizontal principal stress σ H and L h is the axial length of the collapse column perpendicular to the minimum horizontal principal stress σ h and μ is the friction coefficient of the contact surface between the collapse column and the rock mass.

3. The method for evaluating the instability of the collapse column in the longwall coal mining face and comprehensive prevention and control according to claim 1, characterized in that In step S101, According to the instability model: ρgV>∫ A (2c·dA + 2μσ·dA) Conduct instability determination on the collapse column with a penetrated main weak plane; In the formula, ρ is the rock mass density of the collapse column, g is the acceleration of gravity, V is the volume of the collapse column, c is the cohesion of the contact surface between the collapse column and the rock mass, μ is the friction coefficient of the contact surface between the collapse column and the rock mass, A is the contact area of the contact surface between the collapse column and the rock mass, and σ is the extrusion normal stress received by the collapse column.

4. The instability assessment and comprehensive prevention and control method for the collapse column in the longwall coal mining face according to claim 1, characterized in that, In step S101, According to the instability model: Conduct instability determination on the risk of rotary pressure frame of the collapse column; In the formula, F max is the maximum support force of the hydraulic support corresponding to the collapse column; ρ is the rock mass density of the collapse column, g is the acceleration of gravity, V is the volume of the collapse column, L h is the axial length of the collapse column perpendicular to the minimum horizontal principal stress, L 支 is the distance between the hydraulic support and the coal wall of the working face, θ is the rotation angle of the overlying strata of the working face, E i is the elastic modulus of the i-th overlying rock layer, h i is the thickness of the i-th overlying rock layer.

5. The method for evaluating the instability of a collapse column in a longwall coal mining face and comprehensive prevention and control according to claim 1, characterized in that In step S102, In response to the overall sliding or angular rotation of the collapse column, blast in the goaf behind the collapse column to increase the volume of gangue caving and the bulking coefficient, and / or conduct belt filling under the collapse column to support the collapse column.

6. The method for evaluating the instability of collapse columns and comprehensive prevention and control in longwall coal mining faces according to claim 5, characterized in that In step S102, the blast in the goaf behind the collapse column to increase the volume of gangue caving and the bulking coefficient includes: Arrange deep-hole drill holes in a grid pattern in the goaf behind the collapse column, load explosives in the deep-hole drill holes and detonate them in batches to induce the caving of the roof rock stratum; Regulate the blasting parameters to control the bulking coefficient of the caved gangue above 1.2 so that the caved gangue fills the pores of the goaf.

7. The method for evaluating the instability and comprehensively preventing and controlling the collapse column in the longwall coal mining face according to claim 5, wherein In step S102, the conduct of belt filling under the collapse column to support the collapse column includes: Arrange strip-shaped cement wall pairs in the goaf under the collapse column, and fill the area between the cement wall pairs with waste gangue generated during the coal mining process, and the filling process is synchronized with the advancement of the coal mining face to form a strip-shaped continuous support body; wherein, the bulking coefficient of the waste gangue is above 1.

2.

8. The method for evaluating instability and comprehensive prevention and control of collapse columns in longwall coal mining faces according to claim 7, characterized in that In response to The strip width is 10 meters; In response to The strip width is 15 to 20 meters; In response to The strip width is 30 meters; In response to The strip width is 50 meters.

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