Goaf end interval unequal-strength filling pressure-bearing roadway protection method

Abstract

The invention relates to the technical field of pressure relief control of adjacent goaf coal roadways, in particular to a goaf end interval unequal-strength filling pressure-bearing roadway protection method. The roadway protection method comprises the following steps: firstly, determining a bearing pressure distribution function under the mining condition of a complete caving method, then determining a stress rising area as a filling area, and determining a filling body strength analytical expression; and finally, filling schemes corresponding to different filling degrees are designed according to a strength analysis formula of the filling body, numerical simulation checking calculation is carried out on the different filling schemes one by one, and the economic and reasonable optimal filling scheme is finally obtained under the condition that it is guaranteed that the filling body has enough strength. According to the filling scheme obtained through the roadway protection method, the distribution condition of bearing pressure is followed, the filling body has enough supporting strength, and the minimum filling amount is adopted to obtain the optimal filling scheme; on the basis of ensuring a better control effect on overlying strata, the method also has lower construction cost, and is beneficial to being widely used in the field of coal rock pressure relief of adjacent mined areas.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure relief control of adjacent goaf coal roadway, and particularly relates to a method for pressure bearing and roadway protection of interval unequal strong filling at the end of goaf. BACKGROUND

[0002] At present, longwall working face mining of coal resources is generally arranged in underground coal mines in China, and there are a large number of adjacent goaf roadways. Such roadways not only have to bear the loading effect of lateral support pressure of mining, but also have to bear the disturbance effect of overburden structure fracture. The surrounding rock of the adjacent goaf roadway evolves from the cumulative strain state of static loading to the instantaneous high strain rate state. When the bearing structure of the surrounding rock reaches the limit bearing capacity, the adjacent goaf roadway will have large deformation disasters such as roof falling, rib spalling and floor heaving, which seriously restricts the safe, efficient, green and intelligent production of modern mines.

[0003] In order to make the adjacent goaf roadway avoid the lateral support pressure of the longwall working face and the disturbance effect of overburden fracture, the common pressure relief methods of coal and rock in the adjacent goaf include roof cutting, drilling and filling. Industrial test applications have been carried out in the field, and certain control effects have been achieved.

[0004] However, the roof cutting pressure relief technology weakens the adjacent goaf rock pressure by transforming the near-field bearing structure, which cannot avoid the dynamic pressure effect caused by the movement of the far-field bearing structure. Transforming the far-field bearing structure can eliminate the dynamic pressure disturbance of the adjacent goaf rock, but the fracture and collapse of the far-field bearing structure can easily induce ground subsidence, endanger underground water and ground structures, and have defects that cannot be avoided. The drilling pressure relief changes the structure of the shallow surrounding rock of the adjacent goaf roadway, and the surrounding rock enters the plastic bearing state, and the high stress is transferred to the deep coal rock. This method itself is to destroy the bearing structure of the surrounding rock to obtain stress reduction, and the support body is easily damaged. In comparison, the filling method has obvious advantages. On the one hand, it can control the movement state of the overburden roof in the adjacent goaf, keep its integrity, and transfer the deformation, fracture and rotation subsidence movement of the overburden to the non-filling area, away from the adjacent goaf rock mass, so that the adjacent goaf rock mass is in the original rock pressure state, which is beneficial to the stability control of the adjacent goaf roadway.

[0005] Most of the existing filling methods use complete filling, which consumes a large amount of filling material, and because of the local support pressure concentration, the filling body is easily locally damaged and loses its bearing capacity, reducing its control effect on the overburden.

[0006] Therefore, it is necessary to provide an improved technical solution to the above-mentioned deficiencies of the prior art. SUMMARY

[0007] The purpose of the present application is to provide a method for pressure bearing and roadway protection of interval unequal strong filling at the end of goaf, to solve or alleviate the problems existing in the prior art.

[0008] To achieve the above objectives, this application provides the following technical solution: A method for pressure-bearing roadway protection with unequal-strength filling at the end of a goaf, the method comprising the following steps: Step 1: In the plane perpendicular to the axis of the goaf roadway, take the intersection of the side wall and the floor of the goaf roadway near the goaf as the origin, take the direction from the origin to the goaf as the positive x-axis, and take the vertical upward direction from the origin as the positive y-axis, and establish a plane rectangular coordinate system. Based on the bearing characteristics of the elastic coal body on one side of the goaf, and under the condition of complete caving mining, the distribution function f(x) of the internal bearing pressure along the X-axis of the elastic coal body on one side of the goaf is derived. The range of the stress rise zone on the X-axis is determined by the support pressure distribution function f(x), which serves as the filling area d at the end of the goaf. L ; Step 2, assuming the number of filling bodies is n and the width of a single filling body is d. f The distance between two adjacent filling bodies is d g The ratio of the cumulative filling width to the filling area is the filling degree Λ, thus forming a hypothetical filling scheme; Step 3: Establish the mechanical equilibrium equation of the support pressure determined by the assumed full support function f(x) of the filling scheme, so as to obtain the analytical expression of the strength of the filling body g(x); Step 4: Based on the analytical formula for the strength of the filling body g(x), design parameters for filling schemes corresponding to different filling degrees Λ are designed, and numerical simulation is performed to verify the results, thereby determining the optimal filling scheme that is economical and reasonable under the condition of ensuring the strength of the filling body.

[0009] As described above, in the method of pressure-bearing roadway protection with unequal-strength filling at the end of the goaf, preferably, in step 1, based on the basic assumption that the increase in support pressure on one side of the goaf is equal to ζ times the weight of the overlying strata above the width L of the uncompacted area at the end of the goaf, the support pressure distribution function f(x) within the elastic coal body on one side of the goaf is derived as follows: (1); In the formula, f(x) is the bearing pressure distribution function of the elastic coal body on one side of the goaf, in MPa; ζ is the multiple by which the weight of the overburden in the uncompacted area at the end of the goaf is applied to the coal seam in the adjacent goaf; L is the width of the uncompacted area at the end of the goaf, in meters; γH represents the original plumb bob pressure and the original rock pressure of the coal seam being mined, in MPa; k is the peak stress concentration factor of the elastic coal body on one side of the goaf. x is the distance from the origin of the rectangular coordinate system, in meters (m).

[0010] As described above, in the method of uneven-strength filling and pressure-bearing roadway protection at the end of the goaf, a preferred approach is to establish an inequality where the support pressure distribution function f(x) is greater than the original rock pressure γH, in order to solve for the range of the stress rise zone, which is the filling area d at the end of the goaf. L The expression is as follows: (2).

[0011] In the aforementioned method for pressure-bearing roadway protection with unequal-strength filling at the end of a goaf, preferably, in step 2, the cumulative width of the n filling bodies is nd. f The cumulative width of the filling body interval is (n-1)d g The sum of the cumulative width of the filling body and the cumulative width of the filling body interval is the range of high stress in the elastic coal body on one side of the goaf, d. L .

[0012] In the above-described method for pressure-bearing roadway protection with unequal-strength filling at the end of a goaf, preferably, in step 2, the number of filling bodies n, the filling degree Λ, and the width d of a single filling body are... f and the filling space d g The relationship is as follows: (3).

[0013] In the preferred embodiment of the pressure-bearing roadway protection method for unevenly spaced filling at the end of the goaf, as described above, in step 3, the formula for calculating the x-coordinate of the center of the i-th filling body in a plane rectangular coordinate system is as follows: (4).

[0014] In the above-described method for pressure-bearing roadway protection with unequal strength filling at the end of the goaf, preferably, in step 3, the support pressure of the interval area between adjacent filling bodies is borne by the two adjacent filling bodies, thereby distributing the support pressure of the two adjacent filling bodies according to a nonlinear parabolic relationship.

[0015] In the aforementioned method of pressure-bearing roadway protection with unequal-strength filling at the end of the goaf, preferably, the strength analytical expression g(x) of the filling body can be obtained based on the fact that the sum of the uniaxial compressive strengths of all filling bodies is equal to the integral of the support pressure distribution function f(x) with respect to the x-axis. The expression for g(x) is as follows: (5).

[0016] As described above, in the method of filling pressure protection at the end of the goaf with unequal strength, preferably, in step 4, the filling degree Λ varies from 0 to 1. Based on the actual construction conditions, m filling degrees Λ are determined, and then each filling degree is substituted into formulas (3), (4), and (5) to obtain m specific filling schemes.

[0017] As described above, the preferred method for pressure-bearing roadway protection with unequal-strength filling at the end of the goaf involves inputting m filling schemes into a numerical analysis model under actual construction conditions to calculate the distribution law of the supporting pressure of the surrounding rock in the lateral adjacent roadway of the goaf under different filling schemes. The peak stress concentration coefficient, average stress intensity coefficient, and high stress influence range are used as comprehensive evaluation indicators to obtain the optimal filling scheme.

[0018] Compared with the closest prior art, the technical solution of this application has the following beneficial effects: In this roadway protection method, the bearing pressure distribution function under the complete caving mining condition is first determined based on the bearing characteristics of elastic coal. Then, the stress rise zone is identified as the filling area based on this bearing pressure distribution function. Within the filling area, a mechanical equilibrium equation between the assumed filling scheme and the bearing pressure is established to obtain the analytical formula for the strength of the filling body. Finally, based on the analytical formula for the strength of the filling body, filling schemes corresponding to different filling degrees are designed, and numerical simulations are performed on each of the different filling schemes to verify their validity. Ultimately, the optimal filling scheme that is economical and reasonable under the condition of ensuring sufficient strength of the filling body is obtained.

[0019] In other words, the filling scheme obtained by the roadway protection method of this application not only follows the distribution of the supporting pressure, so that the filling body has sufficient supporting strength, but also obtains the optimal filling scheme with the least amount of filling. On the basis of ensuring that the optimal filling scheme has sufficient bearing capacity and better control effect on the overburden, it also has lower construction cost, which is conducive to its widespread use in the field of coal and rock pressure relief in adjacent goaf areas. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. Wherein: Figure 1 This is a schematic diagram of a method for pressure-bearing roadway protection with unequal-strength filling at the end of a goaf, provided according to some embodiments of this application. Figure 2 This describes the effect of filling degree on the support pressure on one side of the goaf, according to some embodiments of this application. Detailed Implementation

[0021] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present application without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present application encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0022] In the following description, the terms "first / second / third" are used merely to distinguish similar objects and do not represent a specific order of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing embodiments of this disclosure only and is not intended to limit this disclosure.

[0024] In the description of this application, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and do not require that this application be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application. The terms "connected," "linked," and "set up" used in this application should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; direct connections or indirect connections through intermediate components; wired connections, radio connections, or wireless communication signal connections. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0025] The present application will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present application can be combined with each other.

[0026] According to specific embodiments of this application, such as Figures 1-2 As shown, this application provides a method for pressure-bearing roadway protection with unequal-strength filling at the end of a goaf. The roadway protection method includes the following steps: Step 1: In a plane perpendicular to the axis of the goaf roadway, establish a Cartesian coordinate system with the intersection of the sidewall and floor of the goaf roadway near the goaf as the origin, the positive x-axis as the direction from the origin to the goaf, and the positive y-axis as the vertical upward direction from the origin.

[0027] Based on the bearing characteristics of the elastic coal body on one side of the goaf, and under the condition of complete caving mining, the distribution function f(x) of the bearing pressure along the X-axis in the elastic coal body on one side of the goaf is derived.

[0028] The range of the stress rise zone on the X-axis is determined by the support pressure distribution function f(x), which serves as the filling area d at the end of the goaf. L .

[0029] Step 2, assuming the number of filling bodies is n and the width of a single filling body is d. f The distance between two adjacent filling bodies is d g The ratio of the cumulative filling width to the filling area is the filling degree Λ, thus forming a hypothetical filling scheme.

[0030] Step 3: Establish the mechanical equilibrium equation of the support pressure determined by the assumed full support function f(x) of the filling scheme, so as to obtain the analytical expression of the strength of the filling body g(x).

[0031] Step 4: Based on the analytical formula for the strength of the filling body g(x), design parameters for filling schemes corresponding to different filling degrees Λ are designed, and numerical simulation is performed to verify the results, thereby determining the optimal filling scheme that is economical and reasonable under the condition of ensuring the strength of the filling body.

[0032] In this roadway protection method, the bearing pressure distribution function under the complete caving mining condition is first determined based on the bearing characteristics of elastic coal. Then, the stress rise zone is identified as the filling area based on this bearing pressure distribution function. Within the filling area, a mechanical equilibrium equation between the assumed filling scheme and the bearing pressure is established to obtain the analytical formula for the strength of the filling body. Finally, based on the analytical formula for the strength of the filling body, filling schemes corresponding to different filling degrees are designed, and numerical simulations are performed on each of the different filling schemes to verify their validity. Ultimately, the optimal filling scheme that is economical and reasonable under the condition of ensuring sufficient strength of the filling body is obtained.

[0033] In other words, the filling scheme obtained by the roadway protection method of this application not only follows the distribution of the supporting pressure, so that the filling body has sufficient supporting strength, but also obtains the optimal filling scheme with the least amount of filling. On the basis of ensuring that the optimal filling scheme has sufficient bearing capacity and better control effect on the overburden, it also has lower construction cost, which is conducive to its widespread use in the field of coal and rock pressure relief in adjacent goaf areas.

[0034] In step 1, based on the fundamental assumption that the increase in support pressure on one side of the goaf is equal to ζ times the weight of the overlying strata above the width L of the uncompacted area at the end of the goaf, the support pressure distribution function f(x) within the elastic coal body on one side of the goaf is derived as follows: (1); In the formula, f(x) is the bearing pressure distribution function of the elastic coal body on one side of the goaf, in MPa; ζ is the multiple by which the weight of the overburden in the uncompacted area at the end of the goaf is applied to the coal seam in the adjacent goaf; L is the width of the uncompacted area at the end of the goaf, in meters; γH represents the original plumb bob pressure and the original rock pressure of the coal seam being mined, in MPa; k is the peak stress concentration factor of the elastic coal body on one side of the goaf. x is the distance from the origin of the rectangular coordinate system, in meters (m). Where x is greater than zero and less than the filling area d at the end of the goaf. L This indicates that in the distribution function, x is located within the filling area at the end of the goaf.

[0035] In this embodiment, assuming the coal body on one side of the goaf is an ideal elastic medium, the maximum supporting pressure at the coal wall of the goaf is kγH. As the distance from the coal wall of the goaf increases, that is, the distance from the origin of the coordinate system gradually decreases, the supporting pressure gradually decays to the original rock pressure γH. The decay rate shows a gradually decreasing trend, and the supporting pressure follows a parabolic decay law. Based on the assumption that the increase in supporting pressure is equal to a multiple of the weight of the overlying rock layer in the uncompacted area at the end of the goaf, the distribution function f(x) of the supporting pressure along the X-axis in the elastic coal body on one side of the goaf can be derived, thus obtaining a more accurate supporting pressure distribution law, providing a solid foundation for determining the optimal filling scheme.

[0036] An inequality is established where the support pressure distribution function f(x) is greater than the original rock pressure γH, in order to solve for the range of the stress rise zone, which is the filling area d at the end of the goaf. L The expression is as follows: (2).

[0037] In this embodiment, the stress-increased region in the support pressure distribution function that is greater than the original rock pressure is the filling region at the end of the goaf that needs to be supported. By establishing the inequality between the support pressure distribution function and the original rock pressure, the expression for the filling region can be solved.

[0038] In step 2, the cumulative width of the n filling bodies is nd. f The cumulative width of the filling body interval is (n-1)d gThe sum of the cumulative width of the filling body and the cumulative width of the filling body interval is the range of high stress in the elastic coal body on one side of the goaf, d. L .

[0039] In step 2, the number of filling bodies n, the filling degree Λ, and the width of a single filling body d are... f and the filling space d g The relationship is as follows: (3).

[0040] In step 3, the formula for calculating the x-coordinate of the center of the i-th filling body in the Cartesian coordinate system is as follows: (4).

[0041] In step 3, the support pressure of the adjacent filling body interval area is borne by the two adjacent filling bodies, thereby distributing the support pressure of the two adjacent filling bodies according to a nonlinear parabolic relationship.

[0042] Based on the fact that the sum of the uniaxial compressive strengths of all filling materials is equal to the integral of the support pressure distribution function f(x) over the x-axis, the analytical expression for the strength of the filling material, g(x), can be obtained. The expression for g(x) is as follows: (5).

[0043] In this embodiment, based on the above analysis, it can be seen that the analytical expression for the strength of the filling body, g(x), still follows a function model similar to the support pressure distribution function f(x) of the elastic coal body on one side of the goaf.

[0044] In step 4, the range of the filling degree Λ is 0 to 1. Based on the actual construction conditions, m filling degrees Λ are determined. Then, each filling degree is substituted into formulas (3), (4), and (5) to obtain m specific filling schemes.

[0045] In this embodiment, each filling degree distribution is substituted with n and d. g g(x) and x i From the formula, the specific parameters of the filling scheme under this filling degree can be obtained, including the number of filling bodies n, the filling degree Λ, and the width of a single filling body d. f and the filling space d g And the center coordinates of each filling body, and the required strength of each filling body.

[0046] Each of the m filling schemes is substituted into a numerical analysis model under actual construction conditions. The distribution law of the supporting pressure of the surrounding rock in the goaf lateral adjacent roadway under different filling schemes is calculated. The peak stress concentration coefficient, average stress intensity coefficient and high stress influence range are used as comprehensive evaluation indicators to obtain the optimal filling scheme.

[0047] In this embodiment, by incorporating filling schemes with different filling degrees into the actual numerical analysis model, the most economical and reasonable filling scheme that meets the comprehensive evaluation index conditions of peak stress concentration factor, average stress concentration factor, and high stress influence range is found. This makes the filling scheme determined by the tunnel protection method have good safety and economy, and the tunnel protection method also has wide applicability.

[0048] The method for protecting the alleyway will be further described in detail below with reference to a specific embodiment.

[0049] Step 1: The original rock pressure γH under the test conditions is 10MPa, the size L of the uncompacted area at the end of the goaf is taken as an empirical value of 45m, ζ is taken as 0.6, and the peak stress concentration factor k is taken as 3. Substituting the above parameters into the formula (1) of this roadway protection method, the support pressure distribution function of the elastic coal body on one side of the goaf under such conditions can be obtained, as shown in formula (6), and the size d of the filling area at the end of the goaf can be determined. L It is approximately 40m.

[0050] (6) Step 2: Determine the test width d of a single filling body based on the field test conditions. f For a depth of 2m, the design filling degrees Λ are 0%, 25%, 50%, 75%, and 100%, respectively. Using the above parameters and the d determined in the first step... L Substituting into equation (3), we can obtain the required number of filling bodies n as 0, 5, 10, 15 and 20, and the distance d between two adjacent filling bodies. g The values ​​are 40.00, 7.50, 2.22, 0.71 and 0.00m respectively.

[0051] Step 3: Substitute the relevant parameters determined in Step 2 into Equation (4) to calculate the x-coordinates of the center of each filling body under different filling degrees, as shown in Table 1. Substitute the relevant parameters determined in Step 1 and Step 2 into Equation (5) to obtain the strength design function g(x) of the filling body corresponding to different filling degrees, as shown in Equation (7).

[0052] Table 1. x-coordinates (m) of the center of each filling body corresponding to different filling degrees.

[0053] (7) Step 4: Substituting the coordinates of each filling body in Table 1 into equation (7) yields the uniaxial compressive strength of each filling body corresponding to different filling degrees Λ, as shown in Table 2. Substituting the end filling schemes of the goaf with unequal strength intervals shown in Tables 1 and 2 into the numerical analysis model at the engineering scale, the distribution law of lateral coal body support pressure in the goaf under different filling schemes is calculated. The peak stress concentration factor, average stress concentration factor, and high stress influence range are used as evaluation indicators. The variation law of these three indicators under such conditions is as follows: Figure 2 As shown, under these conditions, when the filling degree is 50%, all three indicators are relatively small, and the rate of decrease in the three indicators decreases significantly as the filling degree continues to increase. Considering economic costs and material consumption, the optimal filling and pressure relief roadway protection method with unequal strength at the end of the goaf under these conditions is determined as follows: the filling area width is 40m, the filling degree is 50%, the number of filling bodies is 10, the width of a single filling body is 2m, the distance between two adjacent filling bodies is 2.22m, and the strengths of the filling bodies are 10.03, 10.87, 12.85, 15.97, 20.24, 25.64, 32.18, 39.87, 48.69, and 58.65 MPa, respectively.

[0054] Table 2 Uniaxial compressive strength (MPa) of various filling materials with different filling degrees

[0055] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for unevenly spacing the end of the goaf and filling the pressure- bearing protective roadway with strong filling, characterized in that, The method for protecting the roadway comprises the following steps: Step 1, in a plane perpendicular to the axis of the gob-side entry retaining, a plane rectangular coordinate system is established with the intersection point of the side wall of the gob-side entry retaining close to the goaf and the floor as the origin, the positive direction of the x-axis being the direction pointing to the goaf from the origin, and the positive direction of the y-axis being the vertical upward direction; Based on the bearing characteristics of the elastic coal body on one side of the goaf and under the condition of the full caving method, the distribution function f(x) of the abutment pressure along the X-axis in the elastic coal body on one side of the goaf is derived; The stress rise zone range on the X axis is calibrated by the support pressure distribution function f(x) as the goaf end filling area d L ; Step 2, assuming the number of fillers is n, the width of a single filler is d f , the distance between two adjacent fillers is d g , and the ratio of the cumulative filler width to the filling area is the filling degree Λ, thereby forming a hypothetical filling scheme; Step 3, a mechanical equilibrium equation of the abutment pressure determined by the complete support function f(x) of the assumed filling scheme is established to obtain the analytical expression g(x) of the strength of the filling body; Step 4, the filling scheme design parameters corresponding to different filling degrees Λ are designed according to the analytical expression g(x) of the strength of the filling body, and numerical simulation is carried out to determine the optimal filling scheme under the condition of ensuring the strength of the filling body.

2. The gob end interval unequal strength filling pressurized protection roadway method according to claim 1, characterized in that, In step 1, based on the basic assumption that the increase of the abutment pressure on one side of the goaf is equal to the weight of the overburden strata in the un-compacted area at the end of the goaf multiplied by ζ, the distribution function f(x) of the abutment pressure in the elastic coal body on one side of the goaf is derived as follows: （1）； In the formula, f(x) is the distribution function of the abutment pressure in the elastic coal body on one side of the goaf, MPa; ζ is the multiple of the weight of the overburden strata in the un-compacted area at the end of the goaf loaded to the coal body adjacent to the goaf; L is the width of the un-compacted area at the end of the goaf, m; γH is the original plumb pressure and the original rock pressure of the mined coal seam, MPa; k is the peak stress concentration coefficient of the elastic coal body on one side of the goaf; x is the distance from the origin of the rectangular coordinate system, m.

3. The gob end interval unequal strength filling pressurized protection roadway method according to claim 2, characterized in that, The inequality of the support pressure distribution function f(x) being greater than the original rock pressure γH is established to solve the stress rising zone range, that is, the goaf end filling area d L The expression is as follows: (2)。 4. The gob end interval unequal strength filling pressurized rib protection method according to claim 3, characterized in that, In step 2, the cumulative width of the n fillers is nd f , the cumulative width of the filler intervals is (n-1)d g , and the sum of the cumulative width of the fillers and the cumulative width of the filler intervals is the high stress range of the elastic coal body on one side of the goaf d L .

5. The gob end interval unequal strength packing pressure protection gateway method according to claim 4, characterized in that, In step 2, the relationship among the number of fillers n, the filling degree Λ, and the individual filler width d f and the filler interval d g is as follows: （3）。 6. The gob end interval unequal strength packing pressure rib protection method according to claim 5, characterized in that, In step 3, in the rectangular coordinate system, the x-coordinate calculation formula of the center of the i-th filling body is as follows: （4）。 7. The gob end interval unequal strength packing pressure rib protection method according to claim 6, characterized in that, In step 3, the abutment pressure in the interval area between the adjacent filling bodies is borne by the adjacent two filling bodies, so the abutment pressure of the adjacent two filling bodies is distributed according to the nonlinear parabolic relationship.

8. The gob end interval unequal strength packing pressure rib protection method according to claim 7, characterized in that, According to the sum of the uniaxial compressive strengths of all the filling bodies being equal to the integral of the abutment pressure distribution function f(x) with respect to the x-axis, the strength analytical expression g(x) of the filling body is obtained, and the expression is as follows: （5）。 9. The gob end interval unequal strength packing and pressure-bearing alley-protecting method according to claim 8, characterized in that, In step 4, the range of the filling degree Λ is 0-1, m filling degrees Λ are determined according to the actual construction conditions, and then each filling degree is brought into the formulas (3), (4) and (5), so that m specific filling schemes are obtained.

10. The gob end interval unequal strength packing and pressure-laden entry protecting method according to claim 9, characterized in that, The m filling schemes are respectively brought into the numerical analysis model under the actual construction conditions, the abutment pressure distribution law of the goaf side adjacent entry surrounding rock under different filling schemes is calculated, the peak stress concentration coefficient, the average stress concentration coefficient and the high stress influence range are taken as the comprehensive evaluation indexes, and thus the optimal filling scheme is obtained.

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