A method for determining the lag distance of adjacent grouting filling

Abstract

The present invention discloses a method for determining the lag distance of adjacent grouting filling, which is specifically carried out according to the following steps: Step 1, obtain parameters: the maximum diffusion radius of the grout in the goaf, the distance from the advancing position of the goaf to the compacted area, the borehole length, the grouting speed, and the grouting volume when the grout diffusion distance reaches the maximum diffusion radius; Step 2, calculate the lag distance of adjacent grouting filling according to the obtained parameters; obtain the caving height of the goaf according to the empirical formula; obtain the self-flow slope of the grout through the laboratory grouting filling goaf flow diffusion test; calculate the minimum lag distance for the grout not to flow back to the working face and the maximum lag distance for the grouting position not to be in the re-compacted area. The present invention gives a method for determining the lag distance of grout filling through theoretical derivation and laboratory experiments; the calculation method is reasonably designed and the calculation results are relatively accurate, which is of great significance to improving the adjacent filling technology of grout to a certain extent.

Description

Technical Field

[0001] The present invention belongs to the technical field of green treatment of mine solid waste disposal, and specifically relates to a method for determining the lag distance of adjacent grouting filling. Background Technique

[0002] As the main energy source and important raw material in China, coal plays a fundamental and principal role as a "ballast stone" in ensuring China's energy security. With the large-scale development and production of coal resources, the environmental problems caused by solid waste materials such as coal gangue are becoming increasingly serious. With the strict control of environmental protection issues by the state, the treatment of mine solid waste has become an urgent problem to be solved. As a large-scale means of gangue treatment, the gangue slurry filling technology has the advantages of large treatment capacity and no interference with production, and has gradually been applied in some large mines.

[0003] As a layout method of the slurry filling mining technology, the adjacent filling of the slurry grouts into the goaf through the adjacent roadway. When the lag distance of the borehole is too small, it will cause the slurry to flow back to the working face and affect production; when the lag distance is too large, the grouting position will be in the re-compaction area of the goaf, and the grouting effect will be poor. Therefore, the determination of the lag distance of the grouting borehole is an important basis for the safe and efficient treatment of coal gangue by the adjacent slurry filling technology. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for determining the lag distance of adjacent grouting filling, which solves the problems of slurry flowing back to the working face and affecting production and poor grouting effect in the current adjacent slurry filling operation in coal mines.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for determining the lag distance of adjacent grouting filling is specifically carried out according to the following steps:

[0007] Step 1, obtain parameters, including the maximum diffusion radius r of the slurry in the goaf, the distance L1 from the advancing position of the goaf to the compaction area, the borehole length L2, the grouting speed v2, and the grouting volume Q2 when the slurry diffusion distance reaches the maximum diffusion radius r;

[0008] Step 2, calculate the lag distance L of adjacent grouting filling according to the obtained parameters. The calculation formula for the lag distance of adjacent grouting filling is as follows:

[0009]

[0010] In the formula, a is the minimum lag distance for the slurry not to flow back to the working face after filling, and b is the maximum lag distance for the grouting position not to be in the re-compaction area after filling;

[0011] Step 21: Obtain the caving height h1 of the goaf according to the empirical formula, and calculate the final grouting hole height H = h1 - h; h is the safe distance from the borehole to the fissure zone, and the value range is 1.5 - 3m.

[0012] Step 22: Obtain the self-flow slope α of the grout through the laboratory grouting filling goaf flow diffusion test, and the value range is 5 - 15°.

[0013] Step 23: The calculation formula for the grout diffusion radius r in the goaf is as follows:

[0014] r = H × cosα / sin(α + γ);

[0015] In the formula, γ is the coal seam dip angle, which is positive when the working face is mined uphill and negative when mined downhill.

[0016] Step 24: The calculation formulas for the minimum lag distance a where the grout does not flow back to the working face and the maximum lag distance b where the grouting position is not in the recompaction area are as follows:

[0017] a = r - (L2 / v1 + Q2 / v2) × v = H × cosα / sin(α + γ) - (L2 / v1 + Q2 / v2) × v;

[0018] b = L1 - (Q1 / v2 + L2 / v1) × v;

[0019] In the formula, v1 is the borehole speed, v is the working face advancing speed, and Q1 is the designed single-hole grouting volume.

[0020] Step 25: Substitute a and b into the calculation formula for the adjacent position grouting filling lag distance, and we can get:

[0021]

[0022] The features of the present invention also lie in that;

[0023] In Step 1, the distance L1 from the advancing position of the goaf to the compaction area is determined according to the on-site monitoring results.

[0024] In Step 1, the calculation formula for the borehole length L2 is as follows:

[0025] L2 = (M + L3) / COSβ;

[0026] In the formula, M is the coal pillar width, L3 is the length of the arc triangular block, and β is the angle between the borehole and the horizontal plane. In Step 1, the calculation formula for the grouting speed v2 is as follows:

[0027] v2 = v j × S × ρ;

[0028] In the formula, v jv is the slurry flow rate, S is the cross-sectional area of the grouting pipeline, and ρ is the slurry density.

[0029] The slurry flow rate v j Determined according to the slurry loop pipeline transportation test, the value range of the slurry flow rate v j is controlled to be 1.4 - 2.3 m / s.

[0030] In step 1, the acquisition of the grouting volume Q2 when the slurry diffusion distance reaches the maximum diffusion radius r specifically includes the following steps:

[0031] Step 11, design a laboratory grouting and filling goaf flow diffusion test, design the grouting volume as q1, and monitor the grouting volume q2 when the diffusion distance reaches the maximum diffusion radius r during the test;

[0032] Step 12, calculate the grouting volume Q2 when the slurry diffusion distance reaches the maximum diffusion radius r according to the obtained parameters, and the calculation formula is as follows:

[0033] Q2 = Q1 × q2 / q1;

[0034] When monitoring the maximum diffusion radius of the slurry, start calculating when the slurry accumulation height exceeds 1 cm.

[0035] In step 2, when the calculation result is a > b, adjust the final grouting hole height H to make a = L = b.

[0036] The beneficial effects of the present invention are as follows: The present invention provides a method for determining the lag distance of adjacent slurry filling in underground gangue. Through methods such as laboratory tests and theoretical derivation calculations, technical parameters such as the maximum diffusion radius of the slurry in the goaf and the distance from the advancing position of the goaf to the compacted area are obtained. Considering the two factors that the grouting hole position cannot be in the re-compacted area of the goaf, which affects the filling effect, and the slurry cannot flow back to the working face, which affects production, a method for determining the lag distance of slurry filling is given. The calculation method of the present invention is relatively reasonable, the calculation result is relatively accurate, and it has certain practical significance for improving the adjacent slurry filling technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the adjacent borehole grouting and filling profile in a method for determining the lag distance of adjacent grouting and filling of the present invention;

[0038] Figure 2 is the schematic diagram of slurry diffusion in an inclined coal seam in a method for determining the lag distance of adjacent grouting and filling of the present invention;

[0039] Figure 3 is the schematic diagram of the arrangement of grouting boreholes in a method for determining the lag distance of adjacent grouting and filling of the present invention;

[0040] Figure 4It is a schematic diagram of the distribution of the grout in the goaf with the maximum diffusion radius in a method for determining the lag distance of adjacent grouting filling in the present invention;

[0041] Figure 5 It is a schematic diagram of the distribution of the grout in the goaf at the end of grouting in a method for determining the lag distance of adjacent grouting filling in the present invention. Specific embodiments

[0042] The following further details a method for determining the lag distance of adjacent grouting filling in the present invention in conjunction with the accompanying drawings and specific embodiments.

[0043] A method for determining the lag distance of adjacent grouting filling includes the following steps:

[0044] Step 1, obtaining parameters, where the parameters include the diffusion radius r of the grout in the goaf, the distance L1 from the advancing position of the goaf to the compacted area, the drilling length L2, the grouting speed v2, and the grouting volume Q2 when the diffusion distance of the grout reaches the maximum diffusion radius r;

[0045] As Figures 3 - 5 shown, Step 2, calculating the lag distance L of adjacent grouting filling according to the obtained parameters. The calculation formula for the lag distance of adjacent grouting filling is as follows:

[0046]

[0047] a = r - (L2 / v1 + Q2 / v2) × v = H×cosα / sin(α + γ) - (L2 / v1 + Q2 / v2) × v;

[0048] b = L1 - (Q1 / v2 + L2 / v1) × v;

[0049] In the formula, a is the minimum lag distance for the grout not to flow back to the working face after filling, b is the maximum lag distance for the grouting position not to be in the re-compacted area after filling, v1 is the drilling speed, v is the advancing speed of the working face, and Q1 is the designed single-hole grouting volume.

[0050] a = r - (L2 / v1 + Q2 / v2) × v = H×cosα / sin(α + γ) - (L2 / v1 + Q2 / v2) × v;

[0051] b = L1 - (Q1 / v2 + L2 / v1) × v;

[0052] As Figure 1 and Figure 2 shown, obtaining the height H of the final grouting hole: obtaining the caving height h1 of the goaf according to the empirical formula, and calculating the height H of the final grouting hole as H = h1 - h, where h is the safe distance from the drilling hole to the fracture zone, and the value range is 1.5 - 3m;

[0053] The self-flow slope α of the slurry is obtained by measuring the flow diffusion test of grouting and filling the goaf in design, and the value range is 5-15°;

[0054] Calculate the diffusion radius r of the slurry in the goaf, r = H×cosα / sin(α + γ), where γ is the dip angle of the coal seam, γ is positive when the working face is mined uphill and γ is negative when mined downhill;

[0055] The distance L1 between the advancing position of the goaf and the compacted area is mainly obtained by on-site monitoring of mine pressure data and theoretical derivation to obtain the periodic weighting step distance l of the working face, and then calculate the distance L1 between the advancing position of the goaf and the compacted area, L1 = 8l.

[0056] The length L2 of the adjacent grouting borehole is calculated according to the following formula: L2 = (M + L3) / COSβ, where M is the width of the coal pillar, L3 is the length of the arc triangular block, and β is the angle between the borehole and the horizontal plane;

[0057] The grouting speed v2 of the adjacent grouting is calculated according to the following formula: v2 = v j ×S×ρ, where v j is the slurry flow velocity, S is the cross-sectional area of the grouting pipeline, and ρ is the slurry density.

[0058] The method for obtaining the grouting volume Q2 when the slurry diffusion distance reaches the maximum diffusion radius r includes the following steps:

[0059] Step 11, design a laboratory grouting and filling goaf flow diffusion test, design the grouting volume as q1, and monitor the grouting volume q2 when the diffusion distance in the test reaches the maximum diffusion radius r;

[0060] Step 12, calculate the grouting volume Q2 when the slurry diffusion distance reaches the maximum diffusion radius r according to the obtained parameters, and the calculation formula is as follows:

[0061] Q2 = Q1×q2 / q1;

[0062] Further illustrate that when the calculation result is a > b, adjust the final grouting hole height H to make a = L = b.

[0063] A further improvement of the present invention is that the flow velocity of the adjacent filling slurry is determined according to the slurry loop pipeline transportation test, and the value range is 1.4-2.3 m / s.

[0064] A further improvement of the present invention is that when monitoring the maximum diffusion radius of the slurry, the calculation starts when the slurry accumulation height exceeds 1 cm.

[0065] The following further details a method for determining the lag distance of adjacent grouting and filling of the present invention through specific embodiments.

[0066] Embodiment

[0067] Taking a certain mine as an example, the thickness of the workable coal seam in this mine is 3.4 m, the coal seam has no dip angle, the working face is mined by uphill mining, the width of the coal pillar left in the working face is 15 m, the daily advance of the working face is 3.2 m, the periodic weighting interval of the working face measured on site is 12 m, the designed borehole diameter is Φ133 mm, and the designed grouting capacity of a single hole is 12,000 t.

[0068] Using the method of the present invention to determine the lag distance of the adjacent grouting filling borehole Figure 1 It is a cross-sectional view of adjacent borehole grouting filling. The projected length of the borehole in the horizontal plane is the sum of the width of the coal pillar and the projected length of the arc-shaped triangular block in the horizontal plane. The main filling area of the grout is the gap between the original working face section roadway and the accumulated gangue in the caving zone. Figure 3 It is a schematic diagram of the layout of grouting boreholes Figure 4 It is a schematic diagram of the distribution of grout in the goaf with the maximum diffusion radius Figure 5 It is a schematic diagram of the distribution of grout in the goaf after grouting is completed. The sum of the lag distance of the borehole and the advance distance of the working face during the drilling and the grout diffusion to the farthest distance is the diffusion distance of the borehole. The grouting range of the working face is before the recompaction zone of the goaf.

[0069] The method for determining the lag distance of adjacent grouting filling includes the following steps:

[0070] Step 1, obtaining parameters, the parameters include the diffusion radius r of the grout in the goaf, the distance L1 from the advancing position of the goaf to the compaction zone, the borehole length L2, the grouting speed v2, and the grouting volume Q2 when the grout diffusion distance reaches the maximum diffusion radius r;

[0071] Using the empirical formula to obtain the caving zone height of the roof strata in the goaf is 10.8 m, designing a safety distance of 1.8 m, and the designed final hole height H is 9.0 m;

[0072] Measuring through experiments to obtain the self-flow slope α of the grout is 8.5°;

[0073] The distance L1 from the advancing position of the goaf to the compaction zone is L1 = 8l = 96 m.

[0074] The length L2 of the adjacent grouting borehole is calculated according to the following formula: L2 = (M + L3) / COSβ = 42 m.

[0075] The grouting speed v2 of the adjacent grouting is calculated according to the following formula, v j Taking 1.8 m / s: v2 = v j ×S×ρ = 2142 t / d.

[0076] The method for obtaining the grouting volume Q2 when the grout diffusion distance reaches the maximum diffusion radius r includes the following steps:

[0077] Step 11: Design a laboratory grouting filling goaf flow diffusion test with the designed grouting volume of q1, and monitor the grouting volume q2 when the diffusion distance reaches the maximum diffusion radius r during the test;

[0078] Step 12: Calculate the grouting volume Q2 when the grout diffusion distance reaches the maximum diffusion radius r according to the obtained parameters. The calculation formula is as follows:

[0079] Q2 = Q1 × q2 / q1 = 4500t;

[0080] Step 2: Calculate the adjacent grouting filling lag distance L according to the obtained parameters. The calculation formula for the adjacent grouting filling lag distance is as follows:

[0081]

[0082] It can be obtained that 44.88 < L < 69.76. Considering a certain safety distance and making full use of the goaf space, the adjacent grouting filling lag distance is selected as 50m.

[0083] The method for determining the adjacent grouting filling lag distance of the present invention gives a method for determining the grout filling lag distance through reasonable theoretical derivation and laboratory experiments; the calculation method is reasonably designed and the calculation results are relatively accurate, which is of great significance to improving the adjacent grouting filling technology to a certain extent and has certain practicality.

Claims

1. A method for determining the lag distance of adjacent grouting filling, characterized in that, The specific steps are as follows; Step 1: Obtain parameters, where the parameters include the maximum diffusion radius r of the goaf slurry, the distance L1 between the advancing position of the goaf and the compacted area, the drilling length L2, the grouting speed v2, and the grouting volume Q2 when the diffusion distance of the slurry reaches the maximum diffusion radius r; Step 2: Calculate the adjacent grouting filling lag distance L according to the obtained parameters. The calculation formula for the adjacent grouting filling lag distance is as follows: In the formula, a is the minimum lag distance for the slurry not to flow back to the working face after filling, and b is the maximum lag distance for the grouting position not to be in the re-compacted area; Step 21: Obtain the caving height h1 of the goaf according to the empirical formula, and calculate the final grouting hole height H = h1 - h; h is the safe distance from the drilling hole to the fracture zone, and the value range is 1.5 - 3m; Step 22: Obtain the self-flow slope α of the slurry through the laboratory grouting filling goaf flow diffusion test, and the value range is 5 - 15°; Step 23: The calculation formula for the diffusion radius r of the goaf slurry is as follows: r = H×cosα / sin(α + γ); In the formula, γ is the coal seam dip angle, which is positive when the working face is mined uphill and negative when mined downhill; Step 24: The calculation formulas for the minimum lag distance a for the slurry not to flow back to the working face and the maximum lag distance b for the grouting position not to be in the re-compacted area are as follows: a = r - (L2 / v1 + Q2 / v2)×v = H×cosα / sin(α + γ) - (L2 / v1 + Q2 / v2)×v; b = L1 - (Q1 / v2 + L2 / v1)×v; In the formula, v1 is the drilling speed, v is the working face advancing speed, and Q1 is the designed single-hole grouting volume; Step 25: Substitute a and b into the calculation formula for the adjacent grouting filling lag distance, and we can get:

2. The method for determining the lag distance of adjacent grouting filling according to claim 1, characterized in that In Step 1, the distance L1 between the advancing position of the goaf and the compacted area is determined according to the on-site monitoring results.

3. A method for determining the lag distance of adjacent grouting filling, according to claim 1, characterized in that In Step 1, the calculation formula for the drilling length L2 is as follows: L2 = (M + L3) / COSβ; In the formula, M is the coal pillar width, L3 is the length of the arc triangular block, and β is the angle between the drilling hole and the horizontal plane.

4. A method for determining the lag distance of adjacent grouting filling, according to claim 1, characterized in that In Step 1, the calculation formula for the grouting speed v2 is as follows: v2 = v j × S × ρ; Wherein, v j is the slurry flow velocity, S is the cross-sectional area of the grouting pipeline, and ρ is the slurry density.

5. A method for determining the lag distance of adjacent grouting filling, according to claim 4, characterized in that Slurry flow velocity v j Determined according to the slurry loop pipeline transportation test, the slurry flow velocity v j is controlled within the range of 1.4 - 2.3 m / s.

6. The method for determining the lag distance of adjacent grouting filling according to claim 1, characterized in that, In Step 1, the specific steps for obtaining the grouting volume Q2 when the diffusion distance of the slurry reaches the maximum diffusion radius r are as follows: Step 11: Design a laboratory grouting filling goaf flow and diffusion test, with the designed grouting volume being q1, and monitor the grouting volume q when the diffusion distance reaches the maximum diffusion radius r during the test. 2； Step 12: Calculate the grouting volume Q2 when the diffusion distance of the slurry reaches the maximum diffusion radius r according to the obtained parameters. The calculation formula is as follows: Q2 = Q1×q2 / q1.

7. A method for determining the lag distance of adjacent grouting filling, according to claim 6, characterized in that When monitoring the maximum diffusion radius of the slurry, start calculating when the accumulated height of the slurry exceeds 1cm.

8. A method for determining the lag distance of adjacent grouting filling, according to claim 1, characterized in that In Step 2, when the calculation result is a > b, adjust the final grouting hole height H to make a = L = b.

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