WO2023213045A1

WO2023213045A1 - Mining-induced high-level fractured space grouting repair method

Info

Publication number: WO2023213045A1
Application number: PCT/CN2022/124103
Authority: WO
Inventors: 杜锋; 曹正正; 王文强; 李振华; 洪紫杰; 张新超; 李松涛; 樊旋
Original assignee: 河南理工大学
Priority date: 2022-05-06
Filing date: 2022-10-09
Publication date: 2023-11-09
Also published as: CN114876403A; CN114876403B

Abstract

Disclosed in the present invention is a mining-induced high-level fractured space grouting repair method, comprising: collecting in a mining area a coal mining interval of roofing breaking and a coal mining thickness; determining the position of a primary key stratum; determining the fracture form of the primary key stratum, delimiting a water guide fissure area, and, by using a horizontal directional drilling mode, carrying out horizontal drilling along a rock stratum above the primary key stratum and along a rock stratum below the primary key stratum; arranging grouting holes in an area where a bed separation has not been formed in a high-level bed separation zone, starting grouting by a ground grouting station, pumping large slurry particles to the high-level bed separation, plugging, by means of grouting pressure, lower bed separation fissures of the primary key stratum and lower fissures of the primary key stratum, pumping fine particles to a fissure-zone bed separation, and, by means of slurry pressure, plugging upper fissures of the primary key stratum; first grouting the bed separation, and, after the bed separation is grouted, continuing the advance of a working face; and repeating the above steps until the mining is finished. The method of the present invention is reliable and highly practical, and can reduce the probability of occurrence and the extent of harm of a water disaster and a gas disaster for coal mining in the mining area.

Description

A grouting repair method for high-level cracked spaces in mining

Technical field

The invention relates to the technical field of methods for preventing and controlling water damage and gas damage in key layers, and in particular is a method for preventing and controlling cracks in main key layers by directional grouting in the field of preventing and controlling water damage and gas damage in dual-system coal seam mining mines.

Background technique

1. Dual-series coal seam mining will cause the movement and destruction of the overlying rock strata, thereby forming "O" and "X" type cracks in the main key layers; these cracks are communicated from the ground to the coal mining face, and spontaneous coal mine combustion disasters may occur. , producing harmful gases such as CO; when groundwater and some harmful gases exist in the goaf, the main critical layers damaged by mining will cause water vapor to seep into the underground goaf along these cracks, leading to the passage of water in the goaf. The more cracks there are, the greater the amount of underground water inflows, and the more harmful gases will inflow. In severe cases, it will cause roof water damage and gas damage, endangering the safe and efficient production of the mine. As the mining face advances, concentrated stress will be generated above the mine pressure support, which may occur. The risk of strong mine pressure; if relevant measures can be found to seal the cracks in the main key layers, this will greatly reduce the probability of disasters and the degree of harm when disasters occur.

2. Currently, there are two countermeasures to prevent and control roof water and air damage. The first type is the grouting subsidence reduction technology that injects grouting into vertical boreholes in the separation zone. This technology blocks the spread of water vapor to the lower working surface by injecting grouting into the separation zone. The sealing effect is good, but it requires Determine the size of the separation zone in advance, and it is not easy to inject into the separation zone with a small space. The other type is to seal the water-conducting fissure zone. Although this type of water vapor damage prevention and control method can be taught to be easy to inject, it brings the problem that it cannot be completely sealed. Therefore, it is necessary to optimize the above two water and vapor damage prevention and control methods, which must be comprehensive sealing and easy to construct.

Contents of the invention

In order to overcome the shortcomings in the existing technology, the present invention provides a method for grouting repair of high-level fractured space during mining. It combines the coal seam mining coefficient and hydrogeological conditions to determine the utilization level by determining the location of the main key layer and the development status of the separation zone. The directional drilling grouting method seals the separation zone above the main key layer and the separation zone below the main key layer to achieve a method of preventing and controlling water vapor leakage by blocking the main key layer, so as to reduce the degree of water vapor leakage in the goaf area and reduce the risk of water vapor leakage. Underground water and gas hazards threaten the safety and efficiency of mine production.

In order to achieve the above objects, the present invention is implemented according to the following technical solutions:

A grouting repair method for high-level mining cracked spaces includes the following steps:

Step 1. According to the breaking characteristics of the key layers of overlying rock movement, collect the breaking distance and coal thickness of coal mining in the mining area by collecting columnar data of ground drilling in each coal mining area;

Step 2. Use the key layer identification method to identify the location of the key layer of the overlying rock at each borehole, thereby determining the location of the main key layer;

Step 3. Determine the fracture form of the main key layer, delineate the water-conducting fissure area, and determine according to the depth of the coal seam and the drilling conditions on the ground. Use horizontal directional drilling to drill horizontally along the rock layer above the main key layer and the rock layer below the main key layer. ;

Step 4. After the drilling construction is completed, the grouting hole arrangement spacing is determined according to the breaking distance. The grouting holes are arranged in the area of the high-level separation zone where the separation zone has not yet formed. Grouting will be started from the ground grouting station. The granular slurry is pumped to the high-level separation zone, and the grouting pressure is used to seal the cracks in the separation zone below the main critical layer and the cracks in the lower part of the main critical layer; the fine particle slurry is pumped to the cracks to take away the zone, and the slurry pressure is used to seal the cracks in the separation zone below the main critical layer. Seal the cracks in the upper part of the main key layer;

Step 5. Inject grouting into the separation zone first. After the grouting in the separation zone is completed, continue the advancement of the working surface;

Step6. Repeat the above Step1-Step5 until the mining is completed;

Preferably, in Step 2, the key layer judgment method is to use KSPB software judgment;

Specifically, in Step 3, the fracture forms of the main key layer include the "O-X" fracture form, the "O"-shaped fracture part forms a crack that runs up and down, and the "X"-shaped fracture part forms a crack with the upper part closed and the lower part open;

Specifically, in Step 3, the specific method of using horizontal directional drilling is: determine the maximum development position of the high-level separation zone according to the water-conducting fracture zone formula, and use double horizontal directional drilling operations. After leveling the horizontal section, Make the No. 1 horizontal directional borehole located in the fracture zone separation zone, and the No. 2 horizontal directional borehole located in the high-level separation zone;

Specifically, the specific construction layout of double horizontal directional drilling is as follows: both drilling holes are drilled vertically from the ground first, and the No. 1 horizontal directional drilling is completed above the main key layer to straighten the horizontal section so that the horizontal section is located at the main key layer. 3-5m above the layer; No. 2 horizontal directional drilling is completed in the main key layer to straighten the horizontal section so that the horizontal section is located 30cm below the main key layer. Each drill hole is from the direction of the stop line to the direction of the opening. Enables horizontal section drilling to penetrate the entire working surface;

Preferably, in Step 4, the large particle slurry is cement fly ash mixed slurry with a specific gravity of 1.4 to 1.6 mixed with large particle aggregates (such as walnut shells) of 4 to 6 mm or cement fly ash with a specific gravity of 1.3 to 1.5. The slurry is mixed with 2 to 3 mm of fiber-rich aggregate (such as cotton seed shells). The proportion of large particle aggregate is 1 to 2 kg per ¹ m3 of cement fly ash mixed slurry. The fiber-rich aggregate is mixed into the slurry. The specific gravity is 1~2kg per ^1m3 of cement fly ash mixed slurry;

Preferably, in Step 4, the fine particle slurry is a cement fly ash mixed slurry with a specific gravity of 1.1 to 1.3;

Specifically, in Step 4, the specific grouting method is:

Step4.1. After the layout of the No. 2 horizontal directional borehole is completed, arrange a grouting pipe in the channel of the No. 2 horizontal directional borehole. The first grouting hole is located 40m from the opening. First, inject cement with a specific gravity of 1.4 to 1.6 Mix slurry with fly ash and add 2~3mm large particle aggregate. Wait for continuous injection for 2 hours. If the grouting pressure is 0, use fiber-rich aggregate with a particle size of 4~6mm and add cement fly ash. Mix grout for grouting;

Step 4.2. Continue to inject the cement fly ash mixed slurry mixed with rich fiber aggregates until the grouting pressure rises. Continue to use the cement fly ash mixed slurry mixed with large particle aggregates for grouting. When the slurry pressure rises to When the pressure is 1 to 2MPa, use a rapidly solidifying mixed slurry prepared from cement and water glass for grouting. Stop grouting until the slurry pressure rises;

Step 4.3. After the grouting of the high-level separation zone is completed, carry out grouting of the fracture zone and directly inject cement fly ash mixed slurry with a specific gravity of 1.1 to 1.3. Stop grouting when the grouting pressure begins to rise.

Compared with the existing technology, the grouting repair method of the high-level mining cracked space of the present invention has the following beneficial effects:

The invention can mainly be adapted to the determination of main key layers for hole grouting sealing under dual-system mining conditions, and can provide guarantee for the prevention and control of water and gas leakage disasters in mines. Its use method is reliable and has strong practicability.

This invention is based on the influence of coal seam geological occurrence conditions and mining parameters on the development of water-conducting fissure zones in main key layers. It not only considers the distribution area of water-conducting fissure zones in overlying rocks, but also considers the impact of grouting materials and grouting methods on sealing. The influence of plugging effect also ensures that the grouting speed matches the advancement speed of the working face. A comprehensive approach is adopted to grasp the cracks in the main key layer under dual-system mining. By grouting into the separation zone, the grout pressure is used to seal all the key layers. The sealing of cracks not only overcomes the difficulty of grouting by the grouting subsidence method, but also ensures that various parameters such as the grouting speed and working face advancement are matched. In addition, it also ensures the comprehensiveness of the grouting. -X” breaks the cracks for comprehensive sealing. Not only is it safe, reliable and practical, it can also effectively reduce the degree of water vapor leakage and reduce the occurrence of water and air damage.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting any creative effort.

Figure 1 is a plan view of the drilling layout of the grouting repair method for high-level cracked space in mining according to the present invention;

Figure 2 is a cross-sectional view along line A-A in Figure 1 .

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The schematic embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

Figures 1 and 2 are schematic diagrams of a grouting repair method for high-level cracked space in a mining mine in this embodiment, where 1 represents the grouting hole, 2 represents the cutting hole, 3 represents the goaf protection coal pillar, and 4 means "O" type crack, 5 means "X" type crack, 6 means No. 2 horizontal directional drilling, 7 means stop production line, 8 means roadway, 9 means water conductive crack area, 10 means ground grouting station, 11 means In the goaf area, 12 represents the working face, 13 represents the main key layer, 14 represents the near-field key layer, 15 represents the high-level separation area, 16 represents the No. 1 horizontal directional borehole, and 17 represents the fracture zone separation area.

The grouting repair method of high-level mining fracture space in this embodiment includes the following steps:

Step 2. Use the key layer identification method to identify the location of the key layer of the overlying rock at each borehole, thereby determining the location of the main key layer 13;

Step 3. Determine the fracture form of the main key layer 13, delineate the water-conducting fracture area 9, and determine according to the coal seam burial depth and ground drilling conditions to use horizontal directional drilling along the rock layer above the main key layer 13 and below the main key layer 13 Horizontal drilling of rock formations;

Step 4. After the drilling construction is completed, determine the layout spacing of grouting holes 1 based on the breaking distance. Arrange the grouting holes 1 in the area of the high-level separation zone where the separation zone has not yet formed, and start grouting from the ground grouting station 10. , pump the large particle slurry to the high-level separation zone 15, use the grouting pressure to seal the cracks in the lower separation zone of the main key layer 13 and the lower part of the main key layer 13; pump the fine particle slurry to the cracks to take away In layer area 17, use slurry pressure to seal the cracks in the upper part of the main key layer 13;

Step 5. First grout the high-level separation zone 15 and the fissure-zone separation zone 17. After the grouting is completed to the high-level separation zone 15 and the fissure-zone separation zone 17, continue the advancement of the working face 12;

Step6. Repeat the above Step1-Step5 until the mining is completed.

In this embodiment, in Step 2, the key layer identification software KSPB is used to identify the key layer locations of the overlying rock at various boreholes.

In this embodiment, in Step 3, the fracture form of the main key layer 13 includes the "O-X" fracture pattern. The "O"-shaped fracture part forms a crack that penetrates up and down, which is the "O"-shaped crack 4, and the "X"-shaped fracture part forms The crack with the upper part closed and the lower part open is an "X" shaped crack 5.

In this embodiment, in Step 3, the specific method of using horizontal directional drilling is: determining the maximum development position of the high-level separation zone 15 according to the water-conducting fracture zone formula, using double horizontal directional drilling operations, in which horizontal After the section is leveled, the No. 1 horizontal directional borehole 16 is located in the fracture zone separation zone 17, and the No. 2 horizontal directional borehole 6 is located in the high-level separation zone 15.

In this embodiment, the specific construction arrangement of the double horizontal directional drilling is as follows: both drilling holes are drilled vertically from the ground first, and the No. 1 horizontal directional drilling 16 completes the horizontal section straightening above the main key layer 13. The horizontal section is located 3-5m above the main critical layer 13; the No. 2 horizontal directional borehole 6 completes the straightening of the horizontal section in the main critical layer 13 so that the horizontal section is located 30cm below the main critical layer 13. Each drill hole starts from the stop. The mining line 7 direction goes to the cutting hole 2 direction, so that the horizontal section drilling can penetrate the entire working surface 12.

In this embodiment, in Step 4, the large particle slurry is a cement fly ash mixed slurry with a specific gravity of 1.4 to 1.6 mixed with large particle aggregates (such as walnut shells) of 4 to 6 mm or cement powder with a specific gravity of 1.3 to 1.5. The fly ash mixed slurry is mixed with 2 to 3 mm of fiber-rich aggregate (such as cotton seed shells), and the mixing ratio of large particle aggregate is 1 to 2 kg per 1 m ³ of cement fly ash mixed slurry, which is rich in fiber. The specific gravity of the aggregate is 1 to 2 kg per 1 m ³ of cement fly ash mixed slurry; in Step 4, the fine particle slurry is a cement fly ash mixed slurry with a specific gravity of 1.1 to 1.3.

In this embodiment, in Step 4, the specific method of grouting is:

Step4.1. After the layout of the No. 2 horizontal directional borehole 6 is completed, arrange the grouting pipe in the channel of the No. 2 horizontal directional borehole 6. The first grouting hole 1 is located 40 meters away from the opening 2, and the grouting pipe is injected first. The cement and fly ash mixed slurry with a specific gravity of 1.4 to 1.6 is mixed with large particle aggregates of 2 to 3 mm, and the injection is continued for 2 hours. If the grouting pressure is 0, use fiber-rich aggregates with a particle size of 4 to 6 mm. Add cement fly ash mixed slurry for grouting;

Step 4.3. After the grouting of the high-level separation zone 15 is completed, grouting of the fracture zone 17 is carried out. Directly inject cement fly ash mixed slurry with a specific gravity of 1.1 to 1.3. Stop grouting when the grouting pressure begins to rise. .

The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical modifications made based on the technical solution of the present invention fall within the protection scope of the present invention.

Claims

A grouting repair method for high-level mining fracture space, which is characterized by including the following steps:

Step 1. According to the breaking characteristics of the key layers of overlying rock movement, collect the breaking distance and coal thickness of coal mining in the mining area by collecting columnar data of ground drilling in each coal mining area;

Step 2. Use the key layer identification method to identify the location of the key layer of the overlying rock at each borehole, thereby determining the location of the main key layer;

Step 3. Determine the fracture form of the main key layer, delineate the water-conducting fissure area, and determine according to the depth of the coal seam and the drilling conditions on the ground. Use horizontal directional drilling to drill horizontally along the rock layer above the main key layer and the rock layer below the main key layer. ;

Step 4. After the drilling construction is completed, the grouting hole arrangement spacing is determined according to the breaking distance. The grouting holes are arranged in the area of the high-level separation zone where the separation zone has not yet formed. Grouting will be started from the ground grouting station. The granular slurry is pumped to the high-level separation zone, and the grouting pressure is used to seal the cracks in the separation zone below the main key layer and the cracks in the lower part of the main key layer; the fine particles are pumped to the cracks and the separation zone, and the slurry pressure is used to seal the main key layer. Cracks in the upper part of the critical layer;

Step 5. Inject grouting into the separation zone first. After the grouting in the separation zone is completed, continue the advancement of the working surface;

Step6. Repeat the above Step1-Step5 until the mining is completed.
The grouting repair method of high-level mining fracture space according to claim 1, characterized in that in Step 2, the key layer identification method is to use KSPB software identification.
The grouting repair method of high-level mining fracture space according to claim 1, characterized in that, in Step 3, the fracture form of the main key layer includes an "O-X" fracture form, and the "O"-shaped fracture part forms a crack that penetrates up and down, " The X”-shaped broken part forms a crack with the upper part closed and the lower part open.
The method for grouting repair of high-level fractured space in mining according to claim 1, characterized in that, in Step 3, the specific method of adopting horizontal directional drilling is: determining the maximum development of the high-level separation zone according to the water-conducting fracture zone formula Position, use double horizontal directional drilling operations, in which, after leveling the horizontal section, the No. 1 horizontal directional borehole is located in the fracture zone separation zone, and the No. 2 horizontal directional borehole is located in the high-level separation zone.
The grouting repair method for high-level cracked space in mining according to claim 4, characterized in that the specific construction layout of the double horizontal directional drilling is: both drilling holes are drilled vertically from the ground first, and the first one is horizontally oriented. Drill holes above the main key layer to complete the straightening of the horizontal section so that the horizontal section is located 3-5m above the main key layer; No. 2 horizontal directional drilling is completed within the main key layer to straighten the horizontal section so that the horizontal section is located 30cm below the main key layer. , each drill hole is from the stop line direction to the opening direction, so that the horizontal section drilling can penetrate the entire working face.
The method for grouting repair of high-level cracked space in mining according to claim 5, characterized in that in Step 4, the large particle slurry is a cement fly ash mixed slurry with a specific gravity of 1.4 to 1.6 mixed with large particle bones of 4 to 6 mm. Material or cement fly ash mixed slurry with a specific gravity of 1.3 to 1.5 is mixed with 2 to 3 mm of fiber-rich aggregate. The mixing ratio of large particle aggregate is 1 to 1 m3 of cement fly ash mixed slurry. 2kg, the specific gravity of fiber-rich aggregate is 1~2kg per 1m3 of cement fly ash mixed slurry.
The grouting repair method of high-level mining fracture space according to claim 6, characterized in that in Step 4, the fine particle slurry is a cement fly ash mixed slurry with a specific gravity of 1.1 to 1.3.
The grouting repair method of high-level mining fracture space according to claim 7, characterized in that in Step 4, the specific method of grouting is:

Step4.1. After the layout of the No. 2 horizontal directional borehole is completed, arrange a grouting pipe in the channel of the No. 2 horizontal directional borehole. The first grouting hole is located 40m from the opening. First, inject cement with a specific gravity of 1.4 to 1.6 Mix slurry with fly ash and add 2~3mm large particle aggregate. Wait for continuous injection for 2 hours. If the grouting pressure is 0, use fiber-rich aggregate with a particle size of 4~6mm and add cement fly ash. Mix grout for grouting;

Step 4.2. Continue to inject the cement fly ash mixed slurry mixed with rich fiber aggregates until the grouting pressure rises. Continue to use the cement fly ash mixed slurry mixed with large particle aggregates for grouting. When the slurry pressure rises to When the pressure is 1 to 2MPa, use a rapidly solidifying mixed slurry prepared from cement and water glass for grouting. Stop grouting until the slurry pressure rises;

Step 4.3. After the grouting of the high-level separation zone is completed, carry out grouting of the fracture zone and directly inject cement fly ash mixed slurry with a specific gravity of 1.1 to 1.3. Stop grouting when the grouting pressure begins to rise.