Graded targeted plugging method for main water guide channel in non-self-repairing area of overlying strata

Abstract

The invention discloses a graded targeted plugging method for a main water guide channel in an overlying strata non-self-repairing area, which comprises the following steps: firstly, exploring a water guide main channel in an overlying strata water guide crack zone, acquiring coordinate position data of the water guide main channel, and then, carrying out graded grouting on the water guide main channel by utilizing a directional drilling technology, low-density expansion grouting materials are injected into the lower portion of the main water guide channel, light porous cement grouting materials are injected into the middle of the main water guide channel, and cement-based grouting materials are injected into the upper portion of the main water guide channel. According to the method, relevant data of the water guide main channel are explored in the early stage, a directional drilling technology is utilized, grouting is conducted in the water guide main channel, a large amount of grout directly and rapidly enters the water guide main channel for blocking, the grout can diffuse along cracks, the problem that the grout cannot be injected into the water guide main channel is solved, the blocking reliability is greatly improved, and meanwhile the grout consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of repairing water-conducting fissures in overlying strata. Specifically, it is a method for hierarchical targeted plugging of the main water-conducting channels in the non-self-repairing area of overlying strata. Background Art

[0002] Due to underground mining, the overlying strata lose the support of the original strata, causing the overlying strata to move and break, thus forming water-conducting fissures in the overlying strata. On both sides of the mining boundary, the strata move greatly and are severely damaged, forming relatively large water-conducting fissures, which are the main water-conducting channels of the water-conducting fissures in the overlying strata.

[0003] In the artificial repair of roof water-conducting fissures, due to the fracture of the overlying strata, the connectivity between the upper fissures and the underground mining space is relatively good. Traditional grouting methods generally grout the relevant strata. Due to the poor controllability of underground grouting, it is not easy for the grout to quickly, accurately, and in large quantities enter the main water-conducting channel. Even if it enters the main water-conducting channel, it is easy to rush into the goaf under the action of gravity flow and the scouring of water, resulting in the phenomenon of "grout leakage" or "grout burst". As a result, in actual plugging, the existing mature plugging technologies have problems of high cost and poor effect. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a method for hierarchical targeted plugging of the main water-conducting channels in the non-self-repairing area of overlying strata, which takes the main water-conducting channel as the grouting target area, realizes targeted grouting to fill the fissures, quickly and effectively plugs water, and at the same time reduces the construction cost.

[0005] To solve the above technical problem, the present invention provides the following technical solution: A method for hierarchical targeted plugging of the main water-conducting channels in the non-self-repairing area of overlying strata, including the following steps:

[0006] Step A: Explore the main water-conducting channels in the water-conducting fracture zone of the overlying strata, and obtain the coordinate position data of the main water-conducting channels;

[0007] Step B: Primary grouting: Using directional drilling technology, drill a main grouting hole from the ground to the position of the main water-conducting channel, and connect the bottom of the main grouting hole with the bottom of the main water-conducting channel; Use grouting equipment to inject low-density expandable grouting material into the bottom of the main water-conducting channel from the main grouting hole to complete primary grouting and form a first grouting filling layer;

[0008] Step C: Secondary grouting: On the basis of the main grouting hole, use directional drilling technology to deflect and drill in the middle position of the main grouting hole to form a first branch grouting hole, and connect the middle of the first branch grouting hole with the middle of the main water-conducting channel; Use grouting equipment to inject lightweight porous cement grouting material into the middle of the main water-conducting channel from the first branch grouting hole. The lightweight porous cement grouting material is connected with the low-density expandable grouting material to complete secondary grouting and form a second grouting filling layer;

[0009] Step D: Tertiary grouting: Based on the main grouting holes, use directional drilling technology to deflect and drill at the upper position of the main grouting holes to form second branch grouting holes, and the second branch grouting holes are connected to the upper part of the main water-conducting channel; use grouting equipment to inject cement-based grouting material from the second branch grouting holes into the upper part of the main water-conducting channel. The cement-based grouting material is connected to the lightweight porous cement grouting material to complete the tertiary grouting and form the third grouting filling layer; realize the plugging and repair of the entire main water-conducting channel.

[0010] In the above-mentioned hierarchical targeted plugging method for the main water-conducting channel in the non-self-repairing area of overlying strata, the main water-conducting channel is divided into three sections from bottom to top, and the main grouting holes, the first branch grouting holes and the second branch grouting holes are respectively connected to the upper ends of each section of the main water-conducting channel.

[0011] In the above-mentioned hierarchical targeted plugging method for the main water-conducting channel in the non-self-repairing area of overlying strata, the main water-conducting channel is divided into three sections according to the degree of fracture development and water conductivity, which are the bottom section, the middle section and the upper section from bottom to top. The bottom section is the high water-conducting caving zone, the crack opening of the caving zone is from decimeter to meter level, the rock layer is completely collapsed and broken, showing disordered accumulation, and the water conductivity is strong; the middle section is from the top of the caving zone to the middle of the water-conducting fracture zone, the crack opening is from centimeter to decimeter level, the rock layer produces fractures and separation cracks, maintaining a layered structure, and the water conductivity is medium; the upper section is from the middle of the water-conducting fracture zone to the top of the water-conducting fracture zone, the opening is from centimeter to decimeter level, and the water conductivity is the weakest.

[0012] In the above-mentioned hierarchical targeted plugging method for the main water-conducting channel in the non-self-repairing area of overlying strata, the calculation formula for the grouting point height of the main grouting hole is:

[0013] H 底 = H k

[0014] In the formula, H k : The height of the caving zone, unit m; H 底 : The grouting point height of the main grouting hole in the bottom section, unit m;

[0015] The calculation formula for the grouting point height of the first branch grouting hole is:

[0016]

[0017] In the formula, H 中 : The grouting point height of the first branch grouting hole in the middle section, unit m; H 导 : The maximum height of the water-conducting fracture zone, unit m;

[0018] The calculation formula for the grouting point height of the second branch grouting hole is:

[0019] H 顶 = H 导

[0020] In the formula, H 顶 : the height of the grouting point of the second branch grouting hole in the top section, unit: m; H 导 : the height of the maximum water-conducting fractured zone, unit: m.

[0021] For the above-mentioned hierarchical targeted plugging method for the main water-conducting channels in the non-self-healing area of overlying strata, the density of the low-density expanding grouting material is less than that of the lightweight porous cement grouting material, and the density of the lightweight porous cement grouting material is less than that of the cement-based grouting material.

[0022] For the above-mentioned hierarchical targeted plugging method for the main water-conducting channels in the non-self-healing area of overlying strata, the foaming multiple of the low-density expanding grouting material is 20 - 60 times and the compressive strength is 3 - 10 Mpa; the foaming multiple of the lightweight porous cement grouting material is 5 - 20 times and the compressive strength is 10 - 20 Mpa; the cement-based grouting material is a non-foaming conventional mud-based material with a compressive strength of more than 20 MPa.

[0023] For the above-mentioned hierarchical targeted plugging method for the main water-conducting channels in the non-self-healing area of overlying strata, during the first-stage grouting: the total grouting volume is determined according to the volume, fracture rate and foaming agent expansion multiple of the caving zone, the designed grouting pressure value is 2.0 - 4.0 MPa. When the grouting pressure reaches the designed value and the flow rate ≤ 35 L / min lasts for 20 - 30 minutes, stop grouting; for the second-stage grouting: the grouting pressure ≥ the designed value, the grouting rate ≤ 35 L / min lasts for 30 minutes, and stop grouting when the grouting volume ≥ 80% of the designed value; for the third-stage grouting: the total grouting pressure at the end of grouting is not less than 2 - 3 times the maximum hydrostatic pressure of the grouted aquifer, the grouting speed at the end of grouting ≤ 35 L / min, and the duration is greater than 30 minutes.

[0024] The technical solution of the present invention has achieved the following beneficial technical effects:

[0025] By prospecting the relevant data of the main water-conducting channels in the early stage and using the directional drilling technology to grout into the main water-conducting channels, the grout directly, quickly and in large quantities enters the main water-conducting channels for plugging. The grout can diffuse along the fractures, solving the problem that the grout cannot be injected, greatly improving the reliability of plugging, and at the same time reducing the consumption of grout.

[0026] Adopt the "block - solidify - seal" three - level grouting plugging technology. Use low - density grouting materials at the bottom, fill the fissures with low - density expanding materials to slow down the water flow and form a primary water - stop barrier, laying a foundation for subsequent construction. Use medium - density materials in the middle, and strengthen the impermeability of the highly permeable area in the middle with lightweight porous cement. Use high - density materials at the top to achieve the final sealing of the top fissures. Solve the problems of being unable to plug and high cost through the method of step - by - step grouting and step - by - step plugging; after filling at the bottom, it is not necessary to fill the entire caving zone, reducing the filling space and grouting cost; use medium - density grouting materials in the middle. On the one hand, it reduces the use of grouting materials, and on the other hand, it can play an anti - seepage role and also save costs. Brief Description of the Drawings

[0027] Figure 1 Longitudinal sectional schematic diagram of the main water - conducting channel plugged by grouting of the present invention;

[0028] The reference numerals in the figure are represented as: 1 - aquifer; 2 - first grouting filling layer; 3 - second grouting filling layer; 4 - third grouting filling layer; 5 - main grouting hole; 6 - first branch grouting hole; 7 - second branch grouting hole. Detailed Embodiment

[0029] A method for hierarchical targeted plugging of the main water - conducting channel in the non - self - healing area of overlying strata in this embodiment includes the following steps:

[0030] Step A: Detect the main water - conducting channel in the water - conducting fracture zone of overlying strata by means of drilling and other methods, and obtain the coordinate position data of the main water - conducting channel.

[0031] Step B: Primary grouting: Using directional drilling technology, drill the main grouting hole 5 from the ground to the position of the main water - conducting channel, and the main grouting hole 5 is connected to the bottom of the main water - conducting channel; use the grouting equipment to inject low - density expanding grouting material into the bottom of the main water - conducting channel from the main grouting hole 5 to complete the primary grouting.

[0032] Step C: Secondary grouting: On the basis of the main grouting hole 5, use directional drilling technology to deflect and drill in the middle position of the main grouting hole 5 to form the first branch grouting hole 6, and the first branch grouting hole 6 is connected to the middle of the main water - conducting channel; use the grouting equipment to inject lightweight porous cement grouting material into the middle of the main water - conducting channel from the first branch grouting hole 6, and the lightweight porous cement grouting material is connected to the low - density expanding grouting material to complete the secondary grouting.

[0033] Step D: Tertiary grouting: Based on the main grouting hole 5, use directional drilling technology to deflect and drill at the upper position of the main grouting hole 5 to form a second branch grouting hole 7, and the second branch grouting hole 7 is connected to the upper part of the main water-conducting channel; use grouting equipment to inject cement-based grouting material from the second branch grouting hole 7 into the upper part of the main water-conducting channel. The cement-based grouting material is connected to the lightweight porous cement grouting material to complete the tertiary grouting; realize the plugging and repair of the entire main water-conducting channel.

[0034] In steps B to D, the main water-conducting channel is divided into three sections from bottom to top. The main grouting hole 5, the first branch grouting hole 6, and the second branch grouting hole 7 are respectively connected to the upper ends of each section of the main water-conducting channel; the main water-conducting channel is divided into three sections according to the degree of fissure development and water conductivity, which are the bottom section, the middle section, and the upper section from bottom to top. The bottom section is the highly water-conducting caving zone, the fissure opening in the caving zone is from decimeter to meter level, the rock formation is completely caved and broken, showing disordered accumulation, and the water conductivity is strong; the middle section is from the top of the caving zone to the middle of the water-conducting fissure zone, the fissure opening is from centimeter to decimeter level, the rock formation produces fractures and separation cracks, maintaining a layered structure, and the water conductivity is medium; the upper section is from the middle of the water-conducting fissure zone to the top of the water-conducting fissure zone, the opening is from centimeter to decimeter level, and the water conductivity is the weakest. The actual height of each section can be measured through on-site actual measurement data, or by referring to the formula in the Guide for the Setting of Coal Pillars and Coal Mining under Buildings, Water Bodies, Railways and Main Roadways.

[0035] Specifically, the calculation formula for the grouting point height of the main grouting hole 5 is:

[0036] H 底 =H k

[0037] In the formula, H k : the height of the caving zone, unit m; H 底 : the grouting point height of the main grouting hole 5 in the bottom section, unit m;

[0038] The calculation formula for the grouting point height of the first branch grouting hole 6 is:

[0039]

[0040] In the formula, H 中 : the grouting point height of the first branch grouting hole 6 in the middle section, unit m; H 导 : the maximum height of the water-conducting fissure zone, unit m;

[0041] The calculation formula for the grouting point height of the second branch grouting hole 7 is:

[0042] H 顶 =H 导

[0043] In the formula, H 顶: Height of the grouting point of the second branch grouting hole 7 in the top section, unit: m; H 导 : Height of the maximum water-conducting fissure zone, unit: m.

[0044] The density of the low-density expansive grouting material is less than that of the lightweight porous cement grouting material, and the density of the lightweight porous cement grouting material is less than that of the cement-based grouting material; the foaming multiple of the low-density expansive grouting material is 20 - 60 times, and the compressive strength is 3 - 10 Mpa; the foaming multiple of the lightweight porous cement grouting material is 5 - 20 times, and the compressive strength is 10 - 20 Mpa; the cement-based grouting material is a non-foaming conventional mud-based material with a compressive strength of more than 20 MPa. Due to the characteristic of high expansion multiple, the low-density expansive grouting material expands rapidly after being injected into the fissure and plays a filling effect to achieve preliminary water blocking.

[0045] When performing primary grouting: The total grouting volume is determined according to the volume of the caving zone, the fissure rate, and the expansion multiple of the foaming agent. The designed grouting pressure is 2.0 - 4.0 MPa. When the grouting pressure reaches the designed value and the flow rate ≤ 35 L / min for 20 - 30 minutes, stop grouting; for secondary grouting: The grouting pressure ≥ the designed value, the grouting rate ≤ 35 L / min for 30 minutes, and stop grouting when the grouting volume ≥ 80% of the designed value; when performing tertiary grouting: The total grouting pressure at the end of grouting shall not be less than 2 - 3 times the maximum hydrostatic pressure of the grouted aquifer. At the end of grouting, when the grouting speed ≤ 35 L / min and the duration is greater than 30 minutes, grouting can be stopped.

[0046] Obviously, the above embodiments are only examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the claims of this patent application.

Claims

1. A method for hierarchical targeted plugging of dominant water channels in non-self-repairing areas of overburden rock, characterized in that: The following steps are involved: Step A: Exploring the main water-conducting channel in the water-conducting fracture zone of the overburden rock, and obtaining the coordinate position data of the main water-conducting channel; Step B: primary grouting: using directional drilling technology, a main grouting hole (5) is drilled from the ground at the location of the main water guide channel, and the main grouting hole (5) is connected to the bottom of the main water guide channel; using grouting equipment, a low-density expansion grouting material is injected from the main grouting hole (5) into the bottom of the main water guide channel to complete the primary grouting; Step C: Secondary grouting: On the basis of the main grouting hole (5), a directional drilling technique is used to create an inclination and drill in the middle of the main grouting hole (5) to form a first branch grouting hole (6), and the first branch grouting hole (6) is connected to the middle of the main water guide channel; a lightweight porous cement grouting material is injected into the middle of the main water guide channel from the first branch grouting hole (6) by using a grouting device, and the lightweight porous cement grouting material is connected with the low-density expansion grouting material to complete the secondary grouting; Step D: three-stage grouting: on the basis of the main grouting hole (5), a directional drilling technique is used to create an inclination and drill at the upper position of the main grouting hole (5) to form a second branch grouting hole (7), and the second branch grouting hole (7) is connected to the upper part of the main water guide channel; a cement-based grouting material is injected into the upper part of the main water guide channel from the second branch grouting hole (7) by using a grouting device, and the cement-based grouting material is connected to the lightweight porous cement grouting material, thereby completing the three-stage grouting; The entire main water channel is sealed and repaired.

2. A method for hierarchical targeted plugging of dominant water channels in non-self-repairing areas of overburden according to claim 1, characterized in that: The main water-conducting channel is divided into three sections from bottom to top, and the main grouting hole (5), the first branch grouting hole (6) and the second branch grouting hole (7) are respectively connected to the upper end of each section of the main water-conducting channel.

3. A method for hierarchical targeted plugging of dominant water channels in non-self-repairing areas of overburden according to claim 2, characterized in that: The main water-conducting channel is divided into three sections according to the degree of fissure development and water conductivity, namely, the bottom section, the middle section and the upper section from bottom to top. The bottom section is a high-water-conductivity caving zone with a fissure opening of decimeter to meter level. The rock formations are completely collapsed and broken, and are piled up in disorder with strong water conductivity. The middle section is from the top of the caving zone to the middle of the water-conducting fissure zone with a fissure opening of centimeters to decimeters level. The rock formations have fractures and delamination cracks, maintaining a layered structure with medium water conductivity. The upper section is from the middle of the water-conducting fissure zone to the top of the water-conducting fissure zone with an opening of centimeters to decimeters level, and the water conductivity is the weakest.

4. A method for hierarchical targeted plugging of dominant water channels in non-self-repairing areas of overburden according to claim 3, characterized in that: The calculation formula for the grouting point height of the main grouting hole (5) is: H 底 =H k In the formula, H k : Height of the caving zone, unit: m; H 底 : Height of the grouting point of the main grouting hole (5) in the bottom section, in m; The calculation formula for the grouting point height of the first branch grouting hole (6) is: In the formula, H 中 : Height of the grouting point of the first branch grouting hole (6) in the middle section, in m; H 导 : Maximum water-conducting fracture zone height, unit: m; The calculation formula for the height of the grouting point of the second branch grouting hole (7) is: H 顶 =H 导 In the formula, H 顶 : Height of the grouting point of the second branch grouting hole (7) in the top section, in m; H 导 : Maximum water-conducting fracture zone height, unit: m.

5. The method for hierarchical targeted plugging of dominant water channels in non-self-repairing areas of overburden according to claim 1 is characterized in that: The density of the low-density expansive grouting material is less than that of the lightweight porous cement grouting material, and the density of the lightweight porous cement grouting material is less than that of the cement-based grouting material.

6. A method for hierarchical targeted plugging of dominant water channels in non-self-repairing areas of overburden rock according to claim 5, characterized in that: The foaming multiple of low-density expansion grouting material is 20-60 times and the compressive strength is 3-10Mpa; the foaming multiple of lightweight porous cement grouting material is 5-20 times and the compressive strength is 10-20Mpa; cement-based grouting material is a non-foaming conventional mud-based material with a compressive strength of more than 20MPa.

7. A method for hierarchical targeted plugging of dominant water channels in non-self-repairing areas of overburden rock according to claim 6, characterized in that: During the first-level grouting: the total grouting volume is determined based on the volume of the caving zone, the crack rate and the expansion multiple of the foaming agent. The design value of the grouting pressure is 2.0-4.0MPa. When the grouting pressure reaches the design value and the flow rate is ≤35L / min for 20-30 minutes, the grouting is stopped; Second-level grouting: the grouting pressure is ≥ the design value, the grouting rate is ≤35L / min for 30 minutes, and the grouting volume is ≥80% of the design value, so the grouting is stopped; Third-level grouting: at the end of grouting, the total grouting pressure is not less than 2-3 times the maximum hydrostatic pressure of the injected aquifer, the grouting speed is ≤35L / min at the end of grouting, and the duration is greater than 30 minutes.

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