A method for determining the sizes of panel areas and ore pillars in a backfill mining method for thick and large ore bodies

Abstract

The present invention belongs to the technical field of mining, and specifically relates to a method for determining the sizes of a panel and a pillar in a backfill mining method for a thick and large ore body. The steps are as follows: determining the ultimate length of a single backfill stope in the mine based on the Matthews stability diagram method; establishing a mechanical model of a single stope crown pillar, and substituting the ultimate length of the stope into the mechanical model of the single stope crown pillar to obtain the thickness of the crown pillar; establishing the limit equilibrium condition to obtain the maximum deflection model of the panel crown pillar; comparing the subsidence amount with the allowable deflection range in the construction engineering manual, making a value selection to determine the ultimate length of the panel, and then determining the panel length based on the principle of taking the maximum integer number of stopes within the limit panel length; taking the ratio of the panel pillar strength to the load borne by the panel pillar as the safety factor of the pillar, and selecting a reasonable safety factor considering the influence of the actual lateral confinement condition of the pillar on the pillar support capacity to determine the width of the panel pillar. The present invention solves the technical problem that the traditional panel and pillar sizes lack a basis for determination.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground filling mining, and specifically relates to a method for determining the sizes of panels and pillars in a filling mining method for thick and large ore bodies. Background Art

[0002] With the advocacy and popularization of policies such as green mining and environmental protection, more and more underground mines adopt the filling method for mining, especially mines with protection requirements such as rivers, farmlands, and buildings on the surface. The space formed after mining by the filling method is filled with filling materials. However, due to problems such as the quality of filling to the top, the strength of the filling body, and the shrinkage of the filling body, some mines using the filling method for mining, especially mines with large-scale continuous mining, still have problems such as surface movement, subsidence, and cracking of buildings. Therefore, in the design of underground filling mining, panels are usually divided at a certain distance along the length or width direction of the stope, and pillars with a certain width, namely panel pillars, are left between the panels. The division of panels and the leaving of panel pillars are of great significance for controlling the caving of overlying rock and surface subsidence of thick and large ore bodies. Currently, the sizes of panels and panel pillars are usually determined by the method of engineering analogy, lacking corresponding scientific basis. Summary of the Invention

[0003] Technical Problem:

[0004] In view of the above-mentioned disadvantages and deficiencies of the prior art, the present invention provides a method for determining the sizes of filling mining panels and pillars, which solves the problems of surface movement, subsidence, and cracking of buildings caused by the lack of a basis for determining the traditional panel and pillar sizes.

[0005] Technical Solution:

[0006] The present invention proposes a method for determining the sizes of panels and pillars in a filling mining method for thick and large ore bodies, and the steps are as follows:

[0007] S1. Determine the limit length L0 of the ore room of a single filling ore room in the mine based on the Matthews stability diagram method;

[0008] S2. Consider the top pillar of a single ore room as a simply supported beam, and consider the gravity of the filling body in the upper stage as the load acting on the simply supported beam. To meet the strength requirements of the simply supported beam, establish a mechanical model of the top pillar of a single ore room, and substitute the limit length L0 of the ore room into the mechanical model of the top pillar of a single ore room to calculate the thickness δ of the top pillar;

[0009] S3. Consider the top pillar of the entire panel as a floor beam, and consider the gravity of the filling body in the upper-stage panel as the load acting on the floor beam. Establish the limit equilibrium condition to meet the stiffness requirement of the panel top pillar, and obtain the maximum deflection model of the panel top pillar. Compare the settlement amount with the allowable deflection range in the construction engineering manual, make a value selection, determine the limit length of the panel, and then determine the panel length L based on the principle of taking the largest integer number of ore rooms within the limit panel length range.

[0010] S4: Take the ratio of the strength of the panel pillar to the load borne by the panel pillar as the safety factor F of the pillar k , select a reasonable safety factor F considering the influence of the actual side confinement condition of the pillar on the pillar support capacity k , and determine the width W of the panel pillar P .

[0011] Furthermore, the steps of the Matthews stability diagram method in step 1 are as follows:

[0012] S11. Determine the stability number N of the ore room sidewall and roof based on the occurrence boundary conditions of the ore room and the mechanical properties of the ore and rock:

[0013] ;

[0014] In the formula, A is the rock stress coefficient; B is the joint attitude adjustment coefficient; C is the gravity adjustment coefficient; the Q' value takes the approximate value Q, and Q is the rock mass quality index;

[0015] S12. Determine the corresponding hydraulic radius R based on the ore room size:

[0016] ;

[0017] In the formula, S is the projected area of the ore room, S = D × L0, m 2 ; W is the perimeter of the projected area of the ore room, m; W = 2 × (D + L0), D is the width of the ore room, m;

[0018] S13. Substitute the stability number N and the hydraulic radius R into the function expression of the stability - failure line in the Matthews stability diagram to determine the limit length L0 of the ore room;

[0019] The function expression of the stability - failure line in the Matthews stability diagram is:

[0020] ;

[0021] In the formula, N is the stability number and R is the hydraulic radius, m.

[0022] Furthermore, in step S11,

[0023] The rock mass quality index Q is obtained from RMR = 9lnQ + 44, where RMR is the rock mass quality score;

[0024] The rock stress coefficient A has a linear relationship with σ c / σ1, and its value range is: when σ c / σ1 < 2, A = 0.1; when 2 < σ c / σ1 < 10, A = 0.1125(σ c / σ1) - 0.125; when σ c / σ1 > 10, A = 1; where σ c is the uniaxial compressive strength of ore and rock, Mpa; σ1 is the induced stress of the excavation surface, Mpa;

[0025] The joint occurrence adjustment coefficient B is calculated according to the relationship between the joint occurrence and the dip angle of the mining face;

[0026] The gravity adjustment coefficient C is solved by C = 8 - 6cosα, where α is the dip angle of the mining face or goaf surface, °.

[0027] Furthermore, the mechanical model of a single ore room roof pillar in step S2 is:

[0028] ;

[0029] In the formula, δ is the thickness of the roof pillar, m; K is the safety factor with a range of 1.5 - 3; γ is the unit weight of the roof pillar ore and rock, kN / m³; L0 is the ultimate length of the ore room, m; σ t is the tensile strength of ore and rock, MPa.

[0030] Furthermore, the specific steps of step S3 are:

[0031] S31 According to the floor beam mechanical model of the panel roof pillar, the maximum deflection model of the panel roof pillar is derived as:

[0032] ;

[0033] In the formula, E is the elastic modulus of the panel roof pillar, Pa; L is the panel length, m; I is the cross-sectional moment of inertia of the panel roof pillar, m 4 ; q is the overlying load of the panel roof pillar, N / m.

[0034] S32 According to the regulations of the Building Engineering Design Manual, the allowable deflection [ω] of the floor beam ranges from , and taking the range value of this allowable deflection as the maximum deflection, the value range of the panel length L is derived;

[0035] S33 Deform the corrected panel length L based on the settlement amount of the filling body. After filling, the filling body will settle. Determine the corresponding settlement amount Δ according to the filling body ratio and the structural parameters of a single ore chamber. If is satisfied, take . If is satisfied, then take . Substitute it into the maximum deflection model to determine the ultimate panel length, and determine the panel length L based on the maximum number of ore chambers within this value range.

[0036] Furthermore, the load on the panel pillar in step S4 is calculated by the formula:

[0037] ;

[0038] In the formula, is the load on the panel pillar, MPa; γ 均 is the average unit weight of the overlying rock stratum, kN / m³; H is the distance from the top of the ore chamber to the ground surface, m; W p is the width of the pillar, m; h0 is the height of the pillar, m; n is the number of mine levels; δ is the thickness of the roof, m.

[0039] Furthermore, the strength of the panel pillar in step S4 is calculated by the formula:

[0040] ;

[0041] In the formula, is the triaxial compressive strength of the panel ore rock, MPa; ε is a constant. When W P / h0 > 5, ε = 1.4. When W P / h0 < 5, ε = 1.0.

[0042] Furthermore, the safety factor F k in step S4 is greater than 1.

[0043] Beneficial effects:

[0044] A method for determining the sizes of a backfill mining panel and pillars in a thick and large ore body provided by the present invention determines the ultimate length of a single backfill ore chamber through the Matthews stability diagram method to ensure the stability of the roof and side walls during the mining process of a single ore chamber; regards the crown pillar of the ore chamber as a simply supported beam and determines the ultimate thickness of the crown pillar under the condition of meeting the strength requirements; regards the entire panel pillar as a floor beam and determines the panel length range according to the allowable deflection specified in the building engineering design manual, ensuring the stability of the roof and side walls of a single ore chamber while making the crown pillar meet the strength requirements and the entire panel meet the requirements of the maximum deflection deformation; calculates the width of the panel pillar through the pillar support theory and strength calculation formula, considering the lateral confinement condition of the ore body in the backfill loose body, and thus determines the sizes of the panel ore chamber, panel length, and panel pillar, filling the theoretical defect existing in the panel size design. On the premise of ensuring the stability of panel and ore chamber mining, the panel size is increased as much as possible to achieve safe and efficient backfill stoping.

[0045] A method for determining the sizes of a backfill mining panel and pillars in a thick and large ore body provided by the present invention solves the technical problem that the traditional panel and pillar sizes lack a basis for determination, can not only ensure the production capacity of the panel, but also control the pillar ore quantity and ground surface settlement as much as possible, and is suitable for popularization. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is the front view of a panel structure of a thick and large ore body of the present invention;

[0047] Figure 2 is the top view of a panel structure of a thick and large ore body of the present invention;

[0048] Figure 3 is the Matthews stability diagram, where a is the upper limit value of the stability - failure line and b is the lower limit value of the stability - failure line in the figure;

[0049] Figure 4 is the reference diagram for the parameter values in the Matthews stability diagram;

[0050] Figure 5 is the mechanical model of a simply supported beam of a single ore chamber;

[0051] Figure 6 is the mechanical model of a floor beam of the panel;

[0052] Figure 7 is the cross - sectional view of the panel;

[0053] Reference numerals: 1, panel pillar; 2, panel; 3, ore chamber; 4, crown pillar. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] The following further describes in detail the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed descriptions and drawings of the following examples are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms, not limited to the specific embodiments disclosed herein, but including all technical solutions falling within the scope of the claims.

[0055] As Figure 1 and Figure 2 shown, in the design of underground filling mining, panels are usually divided at a certain distance along the length or width direction of the stope, and a pillar with a certain width, namely the panel pillar 1, is left between the panels. The area between two adjacent panel pillars 1 is a panel 2, and a panel 2 is divided into multiple ore rooms 3. A crown pillar 4 is set between adjacent ore rooms 3 in the vertical direction of the ore body (such as the up and down direction shown in Figure 1 ).

[0056] The present invention proposes a method for determining the sizes of panels and pillars in a filling mining method for thick and large ore bodies. The steps are as follows:

[0057] S1. Determine the limit length L0 of a single filling ore room in the mine based on the Matthews stability chart method to ensure the stability of the roof and side walls during the mining of a single ore room 3.

[0058] Specifically: S11. Determine the stability number N of the side walls and roof of the ore room 3 based on the occurrence boundary conditions of the ore room and the mechanical properties of the ore and rock:

[0059] (1)

[0060] In the formula, A is the rock stress coefficient; B is the joint occurrence adjustment coefficient; C is the gravity adjustment coefficient; the Q′ value takes the approximate value Q, which is obtained by transforming through the empirical formula RMR = 9lnQ + 44 between Q and RMR. Q is the rock mass quality index, and RMR is the rock mass quality score; as Figure 4 shown, the rock stress coefficient A has a linear relationship with σ c / σ1, and its value range is: when σ c / σ1 < 2, A = 0.1; when 2 < σ c / σ1 < 10, A = 0.1125(σ c / σ1) - 0.125; when σ c / σ1 > 10, A = 1; σ c is the uniaxial compressive strength of the ore and rock, Mpa; the induced stress of the excavation surface, Mpa; the joint occurrence adjustment coefficient B is calculated according to the relationship between the joint occurrence and the dip angle α of the stope or goaf surface, as Figure 4 shown; the gravity adjustment coefficient C can be solved using the formula C = 8 - 6cosα, where α is the dip angle of the stope or goaf surface, °; as Figure 2As shown in the figure, for the combined plan view of the stope width D and dip angle, the length, area, and dip angle of the goaf are obtained from the plan view and section view of the corresponding stope.

[0061] S12. Determine the corresponding hydraulic radius R based on the dimensions of stope 3:

[0062] (2)

[0063] In the formula, S is the projected area of the stope, S = D×L0, m 2 ; W is the perimeter of the projected area of the stope, W = 2×(D + L0), m; D is the stope width, m;

[0064] S13. Substitute the stability number N and the hydraulic radius R into the function expression of the stability - failure line in the Matthews stability diagram to determine the ultimate length L0 of the stope;

[0065] The function expression of the stability - failure line in the Matthews stability diagram is:

[0066] (3)

[0067] Substitute the stability number N of stope 3 calculated in step S11 and the minimum hydraulic radius R required from stability to failure obtained in step S12 into formula (3) respectively, and then through formula (2), as Figure 3 shown, determine the ultimate length L0 of the stope, and determine the length of stope 3 according to production requirements, so as to maximize the production capacity of panel 2.

[0068] Step S2: Consider the crown pillar 4 of a single stope 3 as a simply - supported beam, and regard the gravity of the filling body in the upper stage as the load q acting on the simply - supported beam. To meet the strength requirements of the simply - supported beam, as Figure 5 shown, establish a mechanical model of the crown pillar of a single stope with the ultimate length L0 of the stope as a parameter to determine the thickness δ of the crown pillar.

[0069] The mechanical model of the crown pillar of a single stope is:

[0070] (4)

[0071] In the formula, δ is the thickness of the crown pillar, m; K is the safety factor with a range of 1.5 - 3; γ is the unit weight of the crown pillar ore and rock, kN / m³; L0 is the ultimate length of the stope, m; σ t is the tensile strength of the ore and rock, MPa.

[0072] Substitute the parameters such as the stope length determined in S1 into formula (4) to obtain the thickness δ of the crown pillar corresponding to the ultimate length L0 of the stope, and then determine the thickness δ of the crown pillar according to production requirements.

[0073] Step S3: Consider the top pillar 4 of the entire panel 2 as a floor beam, and consider the gravity of the filling body in the upper-stage panel 2 as the load q acting on the floor beam. To meet the stiffness requirements of the top pillar 4 of panel 2, establish the limit equilibrium condition to obtain the maximum deflection model of the top pillar 4 of panel 2. Compare the settlement amount with the allowable deflection in the construction engineering manual, make a value selection to determine the limit length of the panel, and then determine the panel length L based on the principle of taking the largest integer number of ore rooms 3 within the limit panel length range.

[0074] S31. Based on the obtained limit length L0 of the ore room and the thickness δ of the top pillar, as Figure 6 shown, according to the floor beam mechanical model of the top pillar 4 of the panel, derive the maximum deflection model of the top pillar 4 of the panel as:

[0075] The maximum deflection model is:

[0076] (5)

[0077] In the formula, E is the elastic modulus of the top pillar of the panel in Pa, L is the panel length in m; I is the sectional moment of inertia of the top pillar of the panel in m 4 , , determine the relationship between the maximum deflection and the panel length L according to the ore-rock mechanical parameters and the size of panel 2, and q is the overlying load on the top pillar of the panel in N / m.

[0078] S32. According to the regulations of the construction engineering design manual, the allowable deflection [ω] range of the floor beam is . Take the range value of this allowable deflection as the maximum deflection , and derive the value range of the panel length L.

[0079] S33. Based on the deformation correction of the settlement of the filling body. After filling, the filling body undergoes settlement. Determine the corresponding settlement amount Δ according to the mixing ratio of the filling body and the structural parameters of a single ore room 3. If , take , if , then take , substitute it into formula (5) to determine the limit length of the panel, and determine the panel length L based on the maximum number of ore rooms 3 within this value range.

[0080] Step S4: Take the ratio of the panel pillar strength to the load borne by the panel pillar as the safety factor F of the pillar k , select a reasonable safety factor F considering the influence of the actual lateral confinement condition of the pillar on the pillar support capacity k , and determine the width W of the panel pillar P .

[0081] Specifically, based on the pillar support theory and strength calculation formula, a reasonable safety factor is selected considering the influence of the actual lateral confinement condition of the panel pillar 1 on its support capacity, and the width W of the panel pillar is determined. P . The steps are as follows:

[0082] S41. According to the pillar support theory, determine the load on the panel pillar:

[0083] (6)

[0084] In the formula, is the load on the panel pillar, MPa; γ 均 is the average unit weight of the overlying rock strata, kN / m³; H is the distance from the top of the stope to the surface, m; W p is the width of the pillar, m; h0 is the height of the pillar, m; n is the number of mine levels; δ is the thickness of the roof, m.

[0085] S42. According to the Bieniaw - ski formula, calculate the strength of the panel pillar:

[0086] (7)

[0087] In the formula, is the triaxial compressive strength of the panel ore - rock, MPa; ε is a constant. When W P / h0 > 5, ε = 1.4. When W P / h0 < 5, ε = 1.0.

[0088] S43. Use the ratio of the strength [σ] of the panel pillar and the load σ p of the panel pillar as the safety factor F k of the pillar to determine the limit value of the width of the panel pillar.

[0089] F k The calculation formula is as follows:

[0090] (8)

[0091] To ensure the safety of the pillar, the safety factor is usually taken as a value greater than 1. Considering that both sides of the panel pillar 1 are backfill bodies, that is, the pillar is under triaxial stress conditions, which is beneficial to the support of the pillar. Therefore, a relatively small value is taken for its safety factor to determine the limit value of the width of the panel pillar 1 and select a reasonable width W of the panel pillar. p .

[0092] Example 1

[0093] This embodiment discloses a method for determining the size of ore pillars in a cut-and-fill mining panel for thick and large ore bodies. An underground iron ore body is selected, which is a steeply inclined ore body with an inclination angle of 65°. The occurrence depth of the ore body is H = 160 m, the vertical extension is 360 m, the ore is moderately stable, the joints are moderately developed, the occurrence is approximately the ore-rock boundary, and the unit weight of the ore is γ = 32 kN·m -3 , the triaxial compressive strength σ c = 135.2 MPa, the tensile strength σ t = 15 MPa, the elastic modulus E = 9.25 GPa, and the RMR score of the ore body is about 72.5. Sublevel caving with subsequent filling is adopted for mining, the stage height is 60 m, the planned width of the stope is D = 15 m, and the unit weight of the filling body is γ c = 20 kN·m -3 .

[0094] S1. Based on the Mathews stability chart method, determine the ultimate length L0 of a single filling stope in the mine, and select a reasonable stope length value according to the production conditions.

[0095] S11. Based on the ore body quality score, calculate the ore body quality index according to the formula RMR = 9lnQ + 44 ; the maximum induced stress σ1 on the excavation surface is 22.41 MPa, σ c / σ1 = 3.5. Therefore, the rock stress coefficient A = 0.1125(σ c / σ1) - 0.125 = 0.269; after the excavation of a single stope, the angle between the joints and the roof and side walls is 65°. Therefore, the value of B is 0.85; through a large number of studies, scholars have found that in the exposed surface of the rock mass, the stability of the vertical side wall is 5 times higher than that of the roof. For an approximately horizontal exposed surface, the coefficient C = 1 is selected. Therefore, the value of the gravity adjustment coefficient C for a single stope is taken as 1; calculate the stability number N of the roof as 5.437 according to formula (1).

[0096] S12. The projected area S of the stope is 15L0, the perimeter W of the projected surface of the stope is 30 + 2L0, and the hydraulic radius R of a single stope is 15L0 / (30 + 2L0);

[0097] S13. Substitute the stability number N calculated in S11 into the function expression (3) of the stability - failure line in the Mathews stability chart, calculate the ultimate hydraulic radius R of the stope when it is stable as 6.137 m, calculate the corresponding ultimate length of the stope as 67.52 m, and take 60 m.

[0098] S2. Regard the crown pillar of a single stope as a simply supported beam, regard the gravity of the filling body in the upper stage as the load acting on the beam, and establish a mechanical model of the crown pillar of a single stope to meet the strength requirements of the simply supported beam:

[0099] (4)

[0100] The unit weight γ of the top pillar ore and rock is 32 kN / m 3 , and the σ t of the top pillar ore and rock is 15 MPa. The safety factor range K of the top pillar is taken as 1.5, and the length L0 of the ore room is 60 m. Substituting these parameters into formula (4), the ultimate thickness of the top pillar is obtained:

[0101] ;

[0102] Therefore, the thickness δ of the panel top pillar can be taken as 6 m.

[0103] S3. Regarding the entire panel top pillar as a floor beam, regarding the gravity of the filling body in the upper stage as the load acting on the floor beam, making the panel top pillar beam meet the stiffness requirements, establishing the limit equilibrium condition, and determining the limit length of the panel; and according to the filling body ratio and the determined settlement amount of the single ore room, verifying and comparing the settlement amount with the allowable deflection in the construction engineering manual, and comprehensively determining the limit length of the panel.

[0104] S31. According to the cross-sectional dimensions of the panel top pillar, as Figure 7 shown, the moment of inertia of the panel cross-section is calculated. According to the mechanical model of the floor beam of the panel top pillar, the relationship between the maximum deflection of the panel top pillar and the panel length is deduced as:

[0105] ;

[0106] S32. The construction engineering design manual stipulates that the allowable deflection [ω] of the floor beam is taken as . To ensure safety, this allowable deflection is taken as the maximum deflection of the panel top pillar, that is

[0107] ;

[0108] The maximum value of the panel length L can be calculated as 128.7 - 162.1 m;

[0109] S33. The shrinkage rate index value of the filling slurry required for filling mining should be less than 3%. According to the filling body height h0 in the ore room being 54 m, the settlement amount Δ of the filling body in the ore room after filling is 54×3% = 1.62 m, which is much larger than the maximum deflection range of 0.81 m of panel 2. Therefore, , calculating L = 162 m, and the maximum number of ore rooms within this range is 10, that is, the panel length L is 150 m.

[0110] S4. Regarding the ratio of the panel pillar strength to the load borne by the panel pillar as the safety factor , select a reasonable safety factor considering the influence of the actual lateral confinement condition of the ore pillar on its support capacity , determine the width W of the panel ore pillar P .

[0111] S41. According to the area bearing theory, determine the load model of the panel ore pillar:

[0112] (6)

[0113] The average unit weight γ of the overlying strata and filling body 均 is taken as 22 kN / m³, the distance H from the top of the stope to the surface is taken as 160 m, the height h0 of the ore pillar is 54 m, the number n of mine levels is 6; the thickness δ of the roof is 6 m. Substitute the above parameters into equation (6) to get:

[0114] ;

[0115] S42. According to the Bieniaw - ski formula, calculate the strength model of the panel ore pillar:

[0116] (7)

[0117] In the formula, σ c is the triaxial compressive strength of the panel ore pillar, taken as 135.2 MPa. The width - height ratio of the ore pillar is generally less than 1, that is W P / A < 1, so ε is taken as 1. Substitute the above parameters into equation (7) to get:

[0118] ;

[0119] S43. Use the ratio of the strength of the ore pillar [σ] and the load σ p of the ore pillar as the safety factor of the ore pillar, and its calculation formula is as follows:

[0120] (9)

[0121] To ensure the safety of the ore pillar, the safety factor is usually taken as a value greater than 1. Considering that both sides of the panel ore pillar are filling bodies, which is beneficial to the support of the ore pillar. Therefore, a relatively small value of the safety factor can meet the strength requirements. Here, the safety factor is taken as 1.05 and substituted into equation (9) to get:

[0122] ;

[0123] Calculate to get W P = 19.67 m, take 20 m.

[0124] As listed above, a method for determining the sizes of a thick and large orebody filling mining panel and ore pillars provided by the present disclosure ensures the stability of the roof and side walls during the mining of a single ore room by determining the ultimate length of a single filled ore room. Regarding the ore pillars of the entire panel as floor beams, the panel length range is determined according to the allowable deflection specified in the building engineering design manual, and the allowable deflection value is selected scientifically based on the shrinkage amount of the filling body to determine the ultimate panel length. The maximum number of ore rooms is determined within the ultimate panel length range, and the final panel length is calculated to make the panel meet the strength and deformation conditions, ensuring mining safety while increasing the panel size as much as possible, reducing the ore quantity of the panel ore pillars, and increasing the mining efficiency. Considering the lateral confinement condition of the orebody in the filling bulk, the width of the panel ore pillars is calculated using the triaxial compressive strength index of the ore and rock, thereby reducing the panel ore pillar size as much as possible. The present invention fills the theoretical defect existing in the panel size design and, on the premise of ensuring the stability of the panel and ore room mining, increases the panel size as much as possible to achieve safe and efficient filling mining.

[0125] So far, the embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details well known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0126] Although some specific embodiments of the present disclosure have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be equivalently replaced without departing from the scope and spirit of the present disclosure. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way.

Claims

1. A method for determining the size of panels and pillars in a thick ore body backfill mining method, characterized in that: The steps are: S1. Determine the limit length L0 of a single filling chamber in a mine based on the Matthews stability diagram method; S2. The top pillar of a single mine room is regarded as a simply supported beam, and the gravity of the filling body in the upper stage is regarded as the load acting on the simply supported beam to meet the strength requirements of the simply supported beam. A mechanical model of the top pillar of a single mine room is established, and the limit length L0 of the mine room is brought into the mechanical model of the top pillar of a single mine room to obtain the thickness δ of the top pillar; S3. The top column of the entire panel area is regarded as the floor beam, and the gravity of the filling body in the upper stage panel area is regarded as the load acting on the floor beam. The top column of the panel area meets the stiffness requirements, and the limit equilibrium condition is established to obtain the maximum deflection model of the top column of the panel area; the settlement amount is compared with the deflection range allowed by the construction engineering manual, and the value is taken to determine the limit length of the panel area. Then, the panel length L is determined based on the principle of taking the maximum integer number of mine rooms within the limit panel length range; S4: Increase the strength of the panel pillars Loads on the panel pillars The ratio of is taken as the safety factor F of the pillar k , consider the influence of the actual side limit conditions of the pillar on the supporting capacity of the pillar and select a reasonable safety factor F k , determine the width W of the panel pillar P .

2. The method for determining the size of the panel and the pillar in the thick ore body backfill mining method according to claim 1, characterized in that: The steps of the Matthews Stability Diagram Method in step 1 are: S11 determines the stability number N of the side walls and roof of the mine room based on the boundary conditions of the mine room and the mechanical properties of the ore rock: ； Where A is the rock stress coefficient; B is the joint attitude adjustment coefficient; C is the gravity adjustment coefficient; Q' value takes the approximate value Q, and Q is the rock mass quality index; S12 determines the corresponding hydraulic radius R based on the size of the mine room: ； Where S is the projected area of ​​the mine room, S=D×L0,m 2 ; W is the perimeter of the mine room projection surface, m; W=2×(D+L0), D is the width of the mine room, m; S13 Substitute the stability number N and the hydraulic radius R into the function expression of the stability-destruction line based on the Matthews stability diagram to determine the ultimate length L0 of the mine room; The functional expression of the stability-destruction line based on the Matthews stability diagram is: ； Where N is the stability number and R is the hydraulic radius, m.

3. The method for determining the size of the panel and the pillar in the thick ore body backfill mining method according to claim 2, characterized in that: In step S11, The rock mass quality index Q is obtained according to RMR=9lnQ+44, where RMR is the rock mass quality score; Rock stress coefficient A and σ c / σ1 is linearly related, and its value range is: when σ c / σ1<2, A=0.1; when 2<σ c / σ1<10, A=0.1125(σ c / σ1)-0.125; when σ c / σ1>10, A=1; where σ c is the uniaxial compressive strength of the ore rock, MPa; σ1 is the induced stress of the excavation surface, MPa; The joint occurrence adjustment coefficient B is calculated based on the relationship between the joint occurrence and the surface inclination angle α of the stope or gob; The gravity adjustment coefficient C is solved by C=8-6cosα, where α is the surface inclination of the stope or gob, degrees.

4. The method for determining the size of the panel and the pillar in the thick ore body backfill mining method according to claim 1, characterized in that: The mechanical model of a single mine roof column in step S2 is: ； Where, δ is the thickness of the top pillar, m; K is the safety factor ranging from 1.5 to 3; γ is the density of the top pillar ore, kN / m³; L0 is the maximum length of the mine room, m; σ t is the tensile strength of rock, MPa.

5. The method for determining the size of the panel and the pillar in the thick ore body backfill mining method according to claim 1, characterized in that: The specific steps of step S3 are: S31 Based on the floor beam mechanical model of the top column of the panel area, the maximum deflection model of the top column of the panel area is derived as follows: ； Where, E is the elastic modulus of the top column of the panel area, Pa; L is the length of the panel area, m; I is the section moment of inertia of the top column of the panel area, m 4 ; q is the overlying load on the top column of the panel area, N / m; S32 According to the Construction Engineering Design Manual, the allowable deflection [ω] of the floor beam is , taking the range of the allowable deflection as the maximum deflection, the range of the length L of the panel area is derived; S33 Deformation correction disc area length L based on the filling body settlement amount. After filling, the filling body will settle. The corresponding settlement amount Δ is determined according to the proportion of the filling body and the structural parameters of a single mine room. If ,Pick ,if , then take , bring the maximum deflection model into play to determine the limit length of the panel area, and determine the panel area length L with the maximum number of chambers within this value range.

6. The method for determining the size of the panel and the pillar in the thick ore body backfill mining method according to claim 1, characterized in that: The load on the panel pillar in step S4 The calculation formula is: ； In the formula, is the column load in the panel area, MPa; γ 均 is the average bulk density of the overlying rock, kN / m³; H is the distance from the top of the mine room to the ground surface, m; W p is the width of the pillar, m; h0 is the height of the pillar, m; n is the number of middle sections in the mine; δ is the thickness of the roof, m.

7. The method for determining the size of the panel and the pillar in the thick ore body backfill mining method according to claim 1, characterized in that: Strength of the panel pillars in step S4 The calculation formula is: ； In the formula, is the triaxial compression strength of the ore rock in the panel area, MPa; h0 is the height of the ore pillar, m; ε is a constant, when W P / When h0>5, ε =1.4, when W P / When h0<5, ε =1.

0.

8. The method for determining the size of the panel and the pillar in the thick ore body backfill mining method according to claim 1, characterized in that: Safety factor F in step S4 k Greater than 1.

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