阅读说明：本技术 一种大采宽厚煤层开采复合注浆方法 (Large-mining-width thick coal seam mining composite grouting method ) 是由 霍超 赵明 齐宽 朱开成 杜金龙 晏嘉 潘海洋 赵岳 殷榕蔚 张志军 苗建 贺 于 2019-10-24 设计创作，主要内容包括：本发明涉及地质灾害防治技术领域,公开了一种大采宽厚煤层开采复合注浆方法,包括：从地表布设钻孔从上往下穿过采空区上方覆岩中的多个目标离层区；通过钻孔对多个目标离层区进行复合注浆填充；其中,所述目标离层区为位于采空区上方覆岩中关键层下方的离层空间。本发明提供的一种大采宽厚煤层开采复合注浆方法,通过向离层空间进行注浆充填,地表的钻孔可只需穿至离层空间即可,无需穿至下方采空区,可以减少钻探工程量,从而可减少工程量以及工程造价,较适用于大采宽厚煤层的开采治理；向采空区上方覆岩中的多个离层空间中进行注浆填充,还可提高注浆量和注采比,更好的满足地表减沉要求,提高注浆效率。(The invention relates to the technical field of geological disaster prevention and control, and discloses a large-mining-width thick coal seam mining composite grouting method, which comprises the following steps: distributing drill holes from the ground surface, and enabling the drill holes to penetrate through a plurality of target separation layer areas in overlying strata above the goaf from top to bottom; performing composite grouting filling on the target separation layer areas through drilling holes; and the target separation layer area is a separation layer space below a key layer in the overlying strata above the goaf. According to the composite grouting method for mining the large-mining-width thick coal seam, the grouting filling is carried out on the separation space, the drill hole in the earth surface can only penetrate through the separation space without penetrating through the goaf below, and the drilling engineering amount can be reduced, so that the engineering amount and the engineering cost can be reduced, and the method is more suitable for mining and governing of the large-mining-width thick coal seam; and grouting filling is carried out in a plurality of separation space in overlying strata above the goaf, so that the grouting amount and the grouting-mining ratio can be improved, the requirement of earth surface subsidence reduction is better met, and the grouting efficiency is improved.)

1. A large-mining-width thick coal seam mining composite grouting method is characterized by comprising the following steps:

distributing drill holes from the ground surface, and enabling the drill holes to penetrate through a plurality of target separation layer areas in overlying strata above the goaf from top to bottom;

performing composite grouting filling on the target separation layer areas through drilling holes;

and the target separation layer area is a separation layer space below a key layer in the overlying strata above the goaf.

2. The composite grouting method for mining the coal seam with large mining width and thick coal seam according to claim 1, characterized in that the target separation zone is determined according to the lithology, thickness and mechanical properties of the upper and lower adjacent strata, so that the overlying strata can be kept stable in the process of carrying out composite grouting filling on a plurality of target separation zones.

3. The method for mining the composite grouting for the large-mining-width thick coal seam according to claim 1, wherein the step of performing composite grouting filling on a plurality of target separation zones through drilling specifically comprises the following steps:

petroleum casing is adopted above a target separation layer area in a drill hole for well cementation, and perforated pipes are arranged below the target separation layer area so as to facilitate grouting in the target separation layer areas;

high pressure grouting is performed from the surface into the borehole.

4. The method for composite grouting for mining of a large-mining-width thick coal seam according to claim 1, wherein the composite grouting and filling of the plurality of target separated zones through drilling further comprises the following steps:

and compacting the rock stratum below the target separation zone to the bottom plate of the coal bed by using high-pressure grouting.

5. The method for composite grouting for mining the coal seam with large mining width and thick coal seam according to claim 1, wherein the composite grouting filling of the multiple target separated zones is carried out by drilling and is carried out synchronously with the mining of the coal seam.

6. The compound grouting method for mining the coal seam with large mining width and thick coal seam according to claim 1, further comprising the following steps of:

before coal seam mining, arranging drill holes from the ground surface to penetrate through a plurality of target separated zones in overlying strata above a goaf from top to bottom;

injecting liquid with certain pressure into the drill hole in advance, and monitoring the formation time of the target separation zone in real time through the pressure change of the liquid so as to determine the grouting time.

7. The compound grouting method for mining the coal seam with large mining width and thick coal seam according to claim 1, wherein the step of arranging a drill hole from the ground surface to penetrate through a plurality of target abscission zones in overlying strata above the goaf from top to bottom specifically comprises the following steps:

judging the position of a key layer according to the early-stage geological exploration result, and determining the position of a target separation layer;

and determining the deployment positions and the number of the drill holes according to the breaking distance of the key layer at the target separation layer and the slurry diffusion radius.

8. The method for mining the composite grouting for the large-mining-width thick coal seam according to claim 1, wherein the step of performing composite grouting filling on a plurality of target separation zones through drilling specifically comprises the following steps:

and injecting the fly ash slurry into the multiple target separated zones, wherein the water-cement ratio of the fly ash slurry is 35-45%.

9. The composite grouting method for mining the coal seam with large mining width and thick coal seam according to claim 3, wherein the grouting pressure for high-pressure grouting from the surface to the borehole is 3-6 MPa.

Technical Field

The invention relates to the technical field of geological disaster prevention and control, in particular to a composite grouting method for mining a large-mining-width thick coal seam.

Background

Coal mining and utilization play a great role in promoting economic development of China, but coal mining subsidence also generates a series of negative influences on the living environment of human beings, and ecological restoration and treatment of a coal mining subsidence area are directly related to sustainable development of the economy, the society and the ecological environment of a mining area, so that the coal mining subsidence area is a difficult problem to be solved urgently in China. About 9X 10 of subsidence land area of existing mining in the country by 2016³km²And with the exploitation of coal resources, the coal mining collapse range is 200km per year²Is incremented. The coal mining subsidence area is comprehensively treated, the ecological environment of a mining area is recovered, meanwhile, the coal mining and the surface subsidence control are considered together, and the implementation of green mining is important work of coal mining in China in future.

The existing filling methods for 'third lower' coal mining mainly comprise strip mining, goaf solid filling, paste filling, ultrahigh water filling mining and the like, and the filling methods have the problems of large initial investment, high filling cost, mutual interference of mining and filling operations, low unit production capacity and work efficiency and the like.

Disclosure of Invention

Technical problem to be solved

The invention aims to provide a large-mining-width thick coal seam mining composite grouting method which is used for solving or partially solving the problems of large initial investment and high filling cost of the existing coal mining filling method.

(II) technical scheme

In order to solve the technical problem, the invention provides a composite grouting method for mining a large-mining-width thick coal seam, which comprises the following steps: distributing drill holes from the ground surface, and enabling the drill holes to penetrate through a plurality of target separation layer areas in overlying strata above the goaf from top to bottom; performing composite grouting filling on the target separation layer areas through drilling holes; and the target separation layer area is a separation layer space below a key layer in the overlying strata above the goaf.

On the basis of the scheme, the target separation zone area is determined according to the lithology, thickness and mechanical properties of the upper and lower adjacent strata, so that the upper overlying strata can be kept stable in the process of grouting and filling the multiple target separation zone areas.

On the basis of the scheme, the composite grouting filling of the multiple target separation layer areas through drilling specifically comprises the following steps: petroleum casing is adopted above a target separation layer area in a drill hole for well cementation, and perforated pipes are arranged below the target separation layer area so as to facilitate grouting in the target separation layer areas; high pressure grouting is performed from the surface into the borehole.

On the basis of the scheme, the composite grouting filling of the multiple target separation zones through drilling further comprises the following steps: and compacting the rock stratum below the target separation zone to the bottom plate of the coal bed by using high-pressure grouting.

On the basis of the scheme, composite grouting filling and coal seam mining are synchronously performed on a plurality of target separation zones through drilling.

On the basis of the scheme, the method further comprises the following steps: before coal seam mining, arranging drill holes from the ground surface to penetrate through a plurality of target separated zones in overlying strata above a goaf from top to bottom; injecting liquid with certain pressure into the drill hole in advance, and monitoring the formation time of the target separation zone in real time through the pressure change of the liquid so as to determine the grouting time.

On the basis of the scheme, the step of distributing drill holes from the earth surface and penetrating through a plurality of target separation zones in overlying strata above the goaf from top to bottom specifically comprises the following steps: judging the position of a key layer according to the early-stage geological exploration result, and determining the position of a target separation layer; and determining the deployment positions and the number of the drill holes according to the breaking distance of the key layer at the target separation layer and the slurry diffusion radius.

On the basis of the scheme, the composite grouting filling of the multiple target separation layer areas through drilling specifically comprises the following steps: and injecting the fly ash slurry into the multiple target separated zones, wherein the water-cement ratio of the fly ash slurry is 35-45%.

On the basis of the scheme, the grouting pressure for performing high-pressure grouting from the ground surface to the borehole is 3-6 MPa.

(III) advantageous effects

According to the composite grouting method for mining the large-mining-width thick coal seam, grouting filling is carried out on the separation space, and the drilled hole in the ground surface can only penetrate through the separation space without penetrating through a goaf below the ground surface; the separation space is smaller relative to the goaf, and the number of drilled holes can be correspondingly reduced, so that the engineering quantity and the engineering cost can be reduced, and the method is more suitable for mining and governing of a large-mining-width thick coal seam; carry out the slip casting to filling in a plurality of abscission layer spaces in the overlying strata above the collecting space area, carry out compound slip casting promptly, can fill a plurality of abscission layer spaces with better elimination residual space, still can improve grouting volume and notes and adopt than, better satisfy the earth's surface and subtract heavy requirement, improve slip casting efficiency.

Drawings

FIG. 1 is a schematic flow chart of a composite grouting method for mining a large-mining-width thick coal seam according to an embodiment of the invention;

fig. 2 is a schematic structural diagram of overlying strata above a goaf in the embodiment of the invention.

Description of reference numerals:

1-bending a sinking strip; 2-fissure zone; 3-falling band;

4-overburden loading; 5, drilling; 6-key layer;

7-target separation zone; 8, isolating the coal pillars; 9-goaf.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The embodiment of the invention provides a large-mining-width thick coal seam mining composite grouting method, and with reference to a figure 1, the method comprises the following steps: distributing drill holes from the ground surface, and enabling the drill holes to penetrate through a plurality of target separation layer areas in overlying strata above the goaf from top to bottom; performing composite grouting filling on the target separation layer areas through drilling holes; and the target separation layer area is a separation layer space below a key layer in the overlying strata above the goaf.

The composite grouting method for mining the thick coal seam with large mining width provided by the embodiment provides grouting in a separation space in overlying strata. Generally, a separation space, namely a gap formed by separation of a key layer and a rock layer below, appears below the key layer of a bending zone of an overlying rock layer of a goaf after coal seam mining. Multiple de-layer spaces may occur below multiple critical layers. By grouting and filling the separation space, the drilled hole on the earth surface can only penetrate through the separation space without penetrating through a goaf below; and the separation space is smaller relative to the goaf, so that the number of drilled holes can be correspondingly reduced, the engineering quantity and the engineering cost can be reduced, and the method is more suitable for mining and governing of a large-mining-width thick coal seam.

Further, the method provides that grouting filling is carried out in a plurality of separation layer spaces in overlying strata above the goaf, namely composite grouting is carried out, the separation layer spaces can be filled to better eliminate residual spaces, the grouting amount and the grouting-mining ratio can be improved, the requirement of ground surface subsidence reduction is better met, and the grouting efficiency is improved.

Furthermore, the method does not perform grouting in each separation space, but determines a plurality of spaces which are more suitable for grouting in the separation spaces as target separation areas, and performs grouting filling in the target separation areas. A borehole from the surface may be drilled sequentially through multiple target isolated zones and into the lowermost target isolated zone. The depth of the borehole is such that it enables the grouting of multiple target separation zones.

Further, the structure of overlying strata above the goaf is shown in fig. 2, and the overlying strata load 4, the bending subsidence zone 1, the fissure zone 2 and the caving zone 3 are arranged from the ground surface downwards in sequence. Wherein, the bending subsidence belt 1 comprises a plurality of key layers 6; the middle below the caving zone 3 is a goaf 9, and two sides are isolation coal pillars 8. The borehole 5 is drilled from the surface down through a plurality of target separation zones 7.

Further, the large mining width refers to a coal seam with the width of a coal face being more than or equal to 300 meters; the thick coal seam refers to a coal seam with the thickness of more than or equal to 3.5 meters.

On the basis of the embodiment, the target separation zone is further determined according to the lithology, thickness and mechanical properties of the upper and lower adjacent strata, so that the upper overlying strata can be kept stable in the process of grouting and filling the multiple target separation zones.

The target separation layer area for grouting is suitable for grouting, and phenomena of geological loosening, collapse and the like cannot be generated in the grouting process. Geological exploration can be performed in advance, the thickness, hardness and mechanical properties of each rock stratum in overlying strata above the goaf are known, and a separation space suitable for grouting is selected as a target separation area. The upper and lower strata of the target separation zone should have certain thickness and hardness, and can bear certain pressure, so that the separation space with softer upper and lower strata is avoided being selected as the target separation zone.

On the basis of the above embodiment, further, the performing composite grouting filling on a plurality of target separation zones by drilling specifically includes: petroleum casing is adopted above a target separation layer area in a drill hole for well cementation, and perforated pipes are arranged below the target separation layer area so as to facilitate grouting in the target separation layer areas; high pressure grouting is performed from the surface into the borehole.

The drill hole penetrates through a plurality of target separation layer areas, and a petroleum casing pipe is arranged in the drill hole and used for connecting an earth surface grouting pump to perform grouting on the target separation layer areas. The section of the petroleum casing pipe penetrating through the target separation zone can be designed as a perforated pipe, namely, the side wall is provided with an opening, so that slurry can flow out to the target separation zone conveniently; the other parts of the petroleum casing pipe, which penetrate through the target separation layer area, can be arranged as common pipes to prevent the slurry from flowing out. The grouting of a plurality of target separation areas by the same drilling hole can be realized, and the engineering quantity and the engineering cost are reduced.

Furthermore, an oil casing pipe can be arranged above the uppermost target separation zone in the drill hole, the bottom of the oil casing pipe is connected with a perforated pipe, and the perforated pipe penetrates from the uppermost target separation zone to the lowermost target separation zone.

Furthermore, the high-pressure grouting effect is mainly embodied as supporting the overlying stratum without breaking the key layer; pressing down the lower stratum to eliminate the residual space of fracture zone and caving zone; with the residual space of elimination that can be better, satisfy the earth's surface and subtract heavy requirement, improve slip casting efficiency.

On the basis of the above embodiment, further, the composite grouting and filling the multiple target separation zones through drilling further comprises: and compacting the rock stratum below the target separation zone to the bottom plate of the coal bed by using high-pressure grouting. The goaf is filled, a stable compaction area can be formed, residual deformation in the stratum is eliminated, and ground subsidence reduction in the coal mining process is realized.

On the basis of the embodiment, further, composite grouting filling is carried out on a plurality of target separated zones through drilling holes, and coal seam mining is carried out synchronously. Namely, the grouting is carried out while the coal seam is mined, and the grouting is not carried out after the coal seam is completely mined. The injection of the slurry may be performed in the mined portion after a section of the coal seam may be mined.

On the basis of the embodiment, further, the method for mining and composite grouting of the large-mining-width thick coal seam further comprises the following steps: before coal seam mining, arranging drill holes from the ground surface to penetrate through a plurality of target separated zones in overlying strata above a goaf from top to bottom; injecting liquid with certain pressure into the drill hole in advance, and monitoring the formation time of the target separation zone in real time through the pressure change of the liquid so as to determine the grouting time.

And a separation space is generated in overlying strata when a goaf is formed by coal seam mining. The method can be used for drilling according to the position of the target separation zone judged in advance, and injecting liquid with certain pressure into the drilled hole to monitor the mining state of the underground coal bed. After the coal seam below the borehole is mined, a separation space is formed in the overlying strata, and liquid in the borehole infiltrates and leaks out along the separation space, so that the pressure of the liquid is reduced. And when the pressure of the liquid in the drill hole is reduced to a preset value, the coal bed below is indicated to be mined, and grouting can be carried out.

The grouting filling and coal seam mining are synchronously carried out on a plurality of target separated layer areas, so that the subsidence treatment can be carried out in the coal seam mining process, a better supporting effect can be realized on the earth surface, and the stability of the earth surface is favorably ensured.

On the basis of the above embodiment, further, the step of laying a borehole from the earth's surface from top to bottom through a plurality of target abscission zones in overlying strata above the goaf specifically comprises: judging the position of a key layer according to the early-stage geological exploration result, and determining the position of a target separation layer; and determining the deployment positions and the number of the drill holes according to the breaking distance of the key layer at the target separation layer and the slurry diffusion radius.

And judging the position and size of the target separation zone according to the hardness and thickness of the upper and lower rock stratums in the separation space and mechanical properties such as breaking distance of a key layer. The drilling hole can be arranged by combining the slurry diffusion radius on the basis of the position and the size of the target separation zone. The number and location of the boreholes is such that the slurry injected through the boreholes fills the target separation zone.

On the basis of the above embodiment, further, the performing composite grouting filling on a plurality of target separation zones by drilling specifically includes: and injecting the fly ash slurry into the multiple target separated zones, wherein the water-cement ratio of the fly ash slurry is 35-45%.

On the basis of the above embodiment, further, the high-pressure grouting pressure from the surface to the borehole is 3-6 Mpa.

On the basis of the embodiment, the composite grouting method for mining the large-mining-width thick coal seam further adopts composite grouting, and belongs to the category of overlying strata abscission layer grouting. Generally, according to the situation that a plurality of separation zones can appear below a key layer of a bending zone of an overlying strata layer during coal mining, composite grouting is carried out on the separation zones, and the composite grouting method is mainly used for comprehensively treating ground subsidence disasters caused by coal mining.

The composite grouting method performs grouting on a plurality of target separation layers, the grouting layers are multiple, and the residual space can be well eliminated from the perspective of the space conservation law; the grouting quantity of the plurality of grouting positions is large, the injection-production ratio is high, and the requirement of surface subsidence reduction can be well met; the grouting efficiency is high.

The existing grouting filling technology for the goaf is mostly applied to surface subsidence reduction in the mining of a thin coal seam with proper mining width, is less in application aiming at the mining of a thick coal seam with large mining width, and has limited subsidence reduction effect. The embodiment aims at the problem of the ground surface subsidence application of the grouting filling technology during the mining of the large-mining-width thick coal seam, and multiple separation spaces below a key layer are selected for composite grouting so as to achieve the effect of ground surface subsidence reduction to the maximum extent.

The composite grouting method is improved on the basis of the existing grouting method, particularly aiming at the exploitation of a coal seam with large mining width and thickness, the upward development speed of a mining space is high, the range is wide, a plurality of separation spaces capable of grouting can be formed above a fracture zone in a short period easily, a grouting station is built on the ground, a drill hole is arranged from the ground surface and drilled through a plurality of target separation zones, the fly ash slurry is injected into the formed separation spaces through a pipeline and the drill hole through a high-pressure pump, and the fly ash precipitates in the separation zones to form a compact body, so that the filling and settlement reducing effects are achieved, and the ground surface settlement is effectively controlled. Wherein the high pressure effect is mainly embodied as supporting the overlying stratum without breaking the key layer; and pressing down the lower stratum to eliminate the residual space of fracture zones and caving zones.

The method comprises the steps of finding out the position of a relatively hard sandstone and a relatively soft shale separation layer above a goaf (a certain distance above a fracture zone) through ground drilling, pressing fly ash grouting (the water-cement ratio is 35% -45%) with an additive into the separation layer through a high-pressure grouting pump, compacting the rock layer at the lower part of the grouting layer to a coal bed bottom plate through fluid pressure while keeping the overlying rock layer stable, forming a stable compaction zone, and eliminating residual deformation in the rock layer. The upper part of the coal mine underground.

The grouting time of the composite grouting is as follows: in the coal mining process, grouting can be started as long as a separation layer is generated at a proper position, and the separation layer is generated below a specific certain key layer by layer without waiting; grouting layer position: multilayer grouting is carried out; injection-production ratio: due to the adoption of composite grouting, the injected slurry amount is greatly increased, the injection-production ratio is improved, and according to space conservation, the more the injected slurry amount is, the smaller the residual space is, and the smaller the ground subsidence is. Geological condition adaptability: if only when single layer position slip casting, if the selected key layer is discontinuous, the separation layer can not be generated, no slip casting space exists, and the composite slip casting can continue to slip casting in the separation layer area below other key layers, so that the slip casting amount can be ensured.

The composite grouting adaptability is strong, and grouting can be implemented in the separation layer area below a plurality of key layers according to grouting subsidence reduction requirements or when key layers are not distributed continuously, so that the grouting amount is guaranteed. The composite grouting can reduce the breaking speed of the stratum from bottom to top, avoid the damage of a grouting hole and contribute to the continuous implementation of the grouting engineering. By adopting separation layer composite grouting, the grouting amount is greatly increased, the injection-production ratio is improved, the residual space is reduced, and the settlement reducing effect is remarkable.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.