阅读说明：本技术 一种底板岩溶水害地面区域治理工作面安全范围确定方法 (Method for determining safety range of control working surface of floor karst water damage ground area ) 是由 张党育 蒋勤明 高春芳 王铁记 王玺瑞 于 2020-04-03 设计创作，主要内容包括：本发明提供了一种底板岩溶水害地面区域治理工作面安全范围确定方法,属于华北型煤田防治水技术领域,所述方法包括获取开采煤层的解析数据；获取防水煤柱宽度计算公式；根据所述解析数据和所述防水煤柱宽度计算公式,得到防水煤柱宽度；获取界限；获取治理工作面安全范围。本发明提供的底板岩溶水害地面区域治理工作面安全范围确定方法,能够依据开采煤层的解析数据、防水煤柱宽度计算公式以及相关工作面是否具有断层构造的情况,来获取界限并最终确定治理工作面安全范围,为华北型煤田底板岩溶水害地面区域的治理工作提供了指导依据。(The invention provides a method for determining a safety range of a control working face of a floor karst water damage ground area, belonging to the technical field of water control in a north China coal field, and the method comprises the steps of obtaining analytic data of a mined coal bed; acquiring a waterproof coal pillar width calculation formula; calculating a formula according to the analytic data and the width of the waterproof coal pillar to obtain the width of the waterproof coal pillar; obtaining a boundary; and acquiring the safety range of the treatment working surface. The method for determining the safety range of the treatment working face of the floor karst water damage ground area can obtain the boundary and finally determine the safety range of the treatment working face according to the analytical data of the mined coal bed, the waterproof coal pillar width calculation formula and the condition whether the related working face has the fault structure, and provides a guidance basis for the treatment work of the floor karst water damage ground area of the North China coal field.)

1. A method for determining the safety range of a control working surface of a floor karst water damage ground area is characterized by comprising the following steps:

acquiring analytical data of a mined coal bed;

acquiring a waterproof coal pillar width calculation formula;

calculating a formula according to the analytic data and the width of the waterproof coal pillar to obtain the width of the waterproof coal pillar;

obtaining a boundary; according to the width of the waterproof coal pillar, acquiring a first limit of an upper gate way on the top surface of Ordovician limestone, acquiring a first limit of a lower gate way, acquiring a first limit of a cutting hole, and acquiring a first limit of a side hole; if the outside of the upper gate way of the working surface has a fault structure, acquiring a second limit of the upper gate way on the top surface of the Ordovician gray; if the outside of the lower gate of the working face has a fault structure, acquiring a second limit of the lower gate on the top surface of Ordovician limestone; if the outer part of the cutting hole of the working surface has a fault structure, acquiring a second limit of the cutting hole on the top surface of Ordovician gray; if the outside of the side eye of the working face has a fault structure, acquiring a second limit of the side eye on the top surface of Ordovician gray;

acquiring a safety range of a treatment working surface; if the fault structure does not exist outside the upper gate way of the working face, taking the first limit of the upper gate way as the outer limit of the upper gate way, and if the fault structure exists outside the upper gate way of the working face, taking the part far away from the upper gate way in the first limit of the upper gate way and the second limit of the upper gate way as the outer limit of the upper gate way; if the fault structure does not exist outside the lower crossheading of the working face, taking the first limit of the lower crossheading as the outer limit of the lower crossheading, and if the fault structure exists outside the lower crossheading of the working face, taking the part far away from the lower crossheading in the first limit of the lower crossheading and the second limit of the lower crossheading as the outer limit of the lower crossheading; if the outer part of the cutting eye of the working surface does not have the fault structure, the first cutting eye limit is taken as the outer cutting eye limit, and if the outer part of the cutting eye of the working surface has the fault structure, the part far away from the cutting eye in the first cutting eye limit and the second cutting eye limit is taken as the outer cutting eye limit; if the side eye of the working surface does not have the fault structure outside the side eye, the side eye first limit is taken as the side eye outer limit, and if the side eye of the working surface has the fault structure outside the side eye, the side eye far away from the side eye in the side eye first limit and the side eye second limit is taken as the side eye outer limit; the safety range of the treatment working face is a range formed by the enclosing of the upper crossheading outer limit, the lower crossheading outer limit, the incision outer limit and the side eye outer limit.

2. The method of claim 1, wherein the obtaining analytical data of the mined coal seam comprises:

and acquiring the water pressure borne by the lowest elevation of the coal seam bottom plate, the thickness of the coal seam, the mining height of the coal seam, the tensile strength of coal and the critical water inrush coefficient.

3. The method for determining the safety range of the treatment working surface of the floor karst water damage ground area according to claim 2, wherein the width calculation formula of the waterproof coal pillar is as follows:

wherein L is waterproof coal pillar width, and K is factor of safety, and M is the great value in coal seam thickness and coal seam height, and P is the water pressure that the minimum elevation of coal seam bottom plate bore, and K is_PIs the tensile strength, T, of coal_SThe critical water inrush coefficient.

4. The method for determining the safety range of the treatment working surface of the floor karst water damage ground area as claimed in claim 3, wherein the safety coefficient is 5.

5. The method for determining the safety range of the governing working face of the floor karst water-damaged ground area according to claim 3, wherein the value of the critical water inrush coefficient is 0.06 MPa/m.

6. The method of claim 1, wherein the safety margin of the working surface for treating the ground area with the karst water is determined,

the acquiring of the first limit of the upper gate way on the top surface of the Ordovician ash comprises: and taking the lowest elevation of the coal bed bottom plate of the upper gate way as a starting point, translating the waterproof coal pillar outwards along the coal bed inclination direction by the width distance, and then obtaining an intersection line intersecting with the top surface of the Ordovician limestone along the normal direction of the rock stratum, wherein the intersection line is taken as a first limit of the upper gate way.

7. The method of claim 1, wherein the safety margin of the working surface for treating the ground area with the karst water is determined,

the obtaining a first boundary of a lower gate way on the top surface of the Ordovician ash comprises: taking the lowest elevation of the coal bed bottom plate of the lower crossheading as a starting point, outwards translating the waterproof coal pillar along the coal bed inclination direction by a width distance, and then projecting along the vertical direction to obtain a projection line on the top surface of the Ordovician limestone, wherein the projection line is taken as a first limit of the lower crossheading;

the acquiring a first margin of a cut hole on an aogrey top surface comprises: taking the lowest elevation of the coal bed bottom plate of the cutting hole as a starting point, translating the waterproof coal pillar outwards along the direction of the coal bed trend for a distance of the width, and then projecting along the vertical direction to obtain a projection line on the top surface of the Ordovician ash, wherein the projection line is taken as a first limit of the cutting hole;

the method for acquiring the first limit of the edge eye on the top surface of the Ordovician gray comprises the following steps: and taking the lowest elevation of the coal bed bottom plate of the side eye as a starting point, translating the waterproof coal pillar outwards along the coal bed trend direction for a distance of the width, and then projecting along the vertical direction to obtain a projection line on the top surface of the Ordovician gray, wherein the projection line is taken as a first limit of the side eye.

8. The method for determining the safety margin of a working surface for treating a ground area with a base plate damaged by karst water according to any one of claims 1 to 7,

if the upper gate way of the working face is externally provided with a fault structure, acquiring a second limit of the upper gate way on the top surface of Ordovician limestone, comprising the following steps: taking the outer side intersection line of the fault plane and the top surface of Ordovician gray as a vertical plane, wherein the second limit of the upper gate way is the intersection line of the vertical plane, which is horizontally moved outwards by a first preset length and then is intersected with the top surface of Ordovician gray;

if the lower gate way of the working face is externally provided with a fault structure, acquiring a second limit of the lower gate way on the top surface of Ordovician limestone, comprising the following steps: taking the outer side intersection line of the fault plane and the top surface of the Ordovician gray as a vertical plane, wherein the second limit of the lower gate way is the intersection line of the vertical plane, which is horizontally moved outwards by a second preset length and then is intersected with the top surface of the Ordovician gray;

if the outer part of the cutting hole of the working surface has a fault structure, acquiring a second limit of the cutting hole on the Ordovician gray top surface, and comprising the following steps: taking the outer side intersection line of the fault plane and the top surface of Ordovician gray as a vertical plane, wherein the second limit of the cutting hole is the intersection line of the vertical plane, which is horizontally moved outwards by a third preset length and then is intersected with the top surface of Ordovician gray;

if the outside of the side eye of the working face has a fault structure, acquiring a second limit of the side eye on the Ordovician gray top surface, comprising: and taking the outer side intersection line of the fault plane and the top surface of the Ordovician gray as a vertical plane, wherein the second limit of the side eye is the intersection line of the vertical plane, which is horizontally moved outwards by a fourth preset length and then is intersected with the top surface of the Ordovician gray.

9. The method of claim 8, wherein the first predetermined length is greater than or equal to 50m, the second predetermined length is greater than or equal to 50m, the third predetermined length is greater than or equal to 50m, and the fourth predetermined length is greater than or equal to 50 m.

Technical Field

The invention belongs to the technical field of water control of North China coal fields, and particularly relates to a method for determining the safety range of a control working surface of a floor karst water damage ground area.

Background

At present, shallow resources of the North China coal fields are basically exhausted, most of the shallow resources are transferred to deep parts, and extremely complex mining conditions of high ground stress, high ground temperature, high water pressure and large disturbance of mining damage of a bottom plate are faced when deep coal seams are mined in coal mines. The method is characterized in that the coal mine underground drilling is carried out to implement grouting transformation of the coal bed bottom plate, and because the water pressure is high, the safety of operators cannot be guaranteed, so that the directional drilling technology is utilized on the ground to carry out regional grouting transformation treatment on the bottom plate Ordovician limestone water-bearing stratum threatening the safety exploitation of the coal bed, and conditions are created for safety production. The main purpose of ground area management is to plug vertical water guide structures such as hidden collapse columns and faults from the root of the Ordovician limestone aquifer, and enough safety distance should be reserved between the lateral direction of the working surface and the vertical water guide structures under the condition that the vertical water guide structures exist at the periphery of the minimum safety management range of the working surface. At present, a method for determining the safety range of a water damage ground area treatment working surface of the North China coal field is not provided in China.

Disclosure of Invention

The invention aims to provide a method for determining the safety range of a control working face of a floor karst water damage ground area, and aims to provide a guidance basis for determining the safety range of the control working face of the water damage ground area of a north China coal field.

In order to achieve the purpose, the invention adopts the technical scheme that: the method for determining the safety range of the treatment working surface of the floor karst water damage ground area comprises the following steps:

acquiring analytical data of a mined coal bed;

acquiring a waterproof coal pillar width calculation formula;

calculating a formula according to the analytic data and the width of the waterproof coal pillar to obtain the width of the waterproof coal pillar;

obtaining a boundary; according to the width of the waterproof coal pillar, acquiring a first limit of an upper gate way on the top surface of Ordovician limestone, acquiring a first limit of a lower gate way, acquiring a first limit of a cutting hole, and acquiring a first limit of a side hole; if the outside of the upper gate way of the working surface has a fault structure, acquiring a second limit of the upper gate way on the top surface of the Ordovician gray; if the outside of the lower gate of the working face has a fault structure, acquiring a second limit of the lower gate on the top surface of Ordovician limestone; if the outer part of the cutting hole of the working surface has a fault structure, acquiring a second limit of the cutting hole on the top surface of Ordovician gray; if the outside of the side eye of the working face has a fault structure, acquiring a second limit of the side eye on the top surface of Ordovician gray;

acquiring a safety range of a treatment working surface; if the fault structure does not exist outside the upper gate way of the working face, taking the first limit of the upper gate way as the outer limit of the upper gate way, and if the fault structure exists outside the upper gate way of the working face, taking the part far away from the upper gate way in the first limit of the upper gate way and the second limit of the upper gate way as the outer limit of the upper gate way; if the fault structure does not exist outside the lower crossheading of the working face, taking the first limit of the lower crossheading as the outer limit of the lower crossheading, and if the fault structure exists outside the lower crossheading of the working face, taking the part far away from the lower crossheading in the first limit of the lower crossheading and the second limit of the lower crossheading as the outer limit of the lower crossheading; if the outer part of the cutting eye of the working surface does not have the fault structure, the first cutting eye limit is taken as the outer cutting eye limit, and if the outer part of the cutting eye of the working surface has the fault structure, the part far away from the cutting eye in the first cutting eye limit and the second cutting eye limit is taken as the outer cutting eye limit; if the side eye of the working surface does not have the fault structure outside the side eye, the side eye first limit is taken as the side eye outer limit, and if the side eye of the working surface has the fault structure outside the side eye, the side eye far away from the side eye in the side eye first limit and the side eye second limit is taken as the side eye outer limit; the safety range of the treatment working face is a range formed by the enclosing of the upper crossheading outer limit, the lower crossheading outer limit, the incision outer limit and the side eye outer limit.

Further, the acquiring analytic data of the mined coal seam comprises:

and acquiring the water pressure borne by the lowest elevation of the coal seam bottom plate, the thickness of the coal seam, the mining height of the coal seam, the tensile strength of coal and the critical water inrush coefficient.

Further, the width calculation formula of the waterproof coal pillar is as follows:

wherein L is waterproof coal pillar width, and K is factor of safety, and M is the great value in coal seam thickness and coal seam height, and P is the water pressure that the minimum elevation of coal seam bottom plate bore, and K is_PIs the tensile strength, T, of coal_SThe critical water inrush coefficient.

Further, the value of the safety factor is 5.

Further, the value of the critical water inrush coefficient is 0.06 MPa/m.

Further, said obtaining an upper gate first limit on the top surface of the Ordovician Ash comprises: and taking the lowest elevation of the coal bed bottom plate of the upper gate way as a starting point, translating the waterproof coal pillar outwards along the coal bed inclination direction by the width distance, and then obtaining an intersection line intersecting with the top surface of the Ordovician limestone along the normal direction of the rock stratum, wherein the intersection line is taken as a first limit of the upper gate way.

Further, said obtaining a first limit of a lower gate on the top surface of the Ordovician Ash comprises: taking the lowest elevation of the coal bed bottom plate of the lower crossheading as a starting point, outwards translating the waterproof coal pillar along the coal bed inclination direction by a width distance, and then projecting along the vertical direction to obtain a projection line on the top surface of the Ordovician limestone, wherein the projection line is taken as a first limit of the lower crossheading;

the acquiring a first margin of a cut hole on an aogrey top surface comprises: taking the lowest elevation of the coal bed bottom plate of the cutting hole as a starting point, translating the waterproof coal pillar outwards along the direction of the coal bed trend for a distance of the width, and then projecting along the vertical direction to obtain a projection line on the top surface of the Ordovician ash, wherein the projection line is taken as a first limit of the cutting hole;

the method for acquiring the first limit of the edge eye on the top surface of the Ordovician gray comprises the following steps: and taking the lowest elevation of the coal bed bottom plate of the side eye as a starting point, translating the waterproof coal pillar outwards along the coal bed trend direction for a distance of the width, and then projecting along the vertical direction to obtain a projection line on the top surface of the Ordovician gray, wherein the projection line is taken as a first limit of the side eye.

Further, if there is a fault structure outside the upper gate of the working surface, acquiring a second limit of the upper gate on the top surface of the austempered grey scale, including: taking the outer side intersection line of the fault plane and the top surface of Ordovician gray as a vertical plane, wherein the second limit of the upper gate way is the intersection line of the vertical plane, which is horizontally moved outwards by a first preset length and then is intersected with the top surface of Ordovician gray;

if the lower gate way of the working face is externally provided with a fault structure, acquiring a second limit of the lower gate way on the top surface of Ordovician limestone, comprising the following steps: taking the outer side intersection line of the fault plane and the top surface of the Ordovician gray as a vertical plane, wherein the second limit of the lower gate way is the intersection line of the vertical plane, which is horizontally moved outwards by a second preset length and then is intersected with the top surface of the Ordovician gray;

if the outer part of the cutting hole of the working surface has a fault structure, acquiring a second limit of the cutting hole on the Ordovician gray top surface, and comprising the following steps: taking the outer side intersection line of the fault plane and the top surface of Ordovician gray as a vertical plane, wherein the second limit of the cutting hole is the intersection line of the vertical plane, which is horizontally moved outwards by a third preset length and then is intersected with the top surface of Ordovician gray;

if the outside of the side eye of the working face has a fault structure, acquiring a second limit of the side eye on the Ordovician gray top surface, comprising: and taking the outer side intersection line of the fault plane and the top surface of the Ordovician gray as a vertical plane, wherein the second limit of the side eye is the intersection line of the vertical plane, which is horizontally moved outwards by a fourth preset length and then is intersected with the top surface of the Ordovician gray.

Further, the first preset length is greater than or equal to 50m, the second preset length is greater than or equal to 50m, the third preset length is greater than or equal to 50m, and the fourth preset length is greater than or equal to 50 m.

The method for determining the safety range of the governing working face of the floor karst water damage ground area has the advantages that: compared with the prior art, the boundary can be obtained and the safety range of the treatment working face can be finally determined according to the analytical data of the mined coal bed, the waterproof coal pillar width calculation formula and the condition whether the related working face has the fault structure, and a guidance basis is provided for the treatment work of the water-soluble ground area of the bottom plate rock of the north China coal field.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a flow chart of a method for determining a safety range of a governing working surface of a floor karst water damage ground area according to an embodiment of the invention;

FIG. 2 is a schematic diagram of a method for determining a safety range of a treatment working surface of a floor karst water damage ground area, which is provided by an embodiment of the invention, when the method is applied to a faultless structure to determine the safety range of the treatment working surface;

FIG. 3 is one of schematic diagrams of a method for determining a safety range of a treatment working surface of a floor karst water damage ground area, which is provided by an embodiment of the present invention, when the safety range of the treatment working surface is determined when a fault structure exists;

fig. 4 is a second schematic diagram of the method for determining the safety range of the treatment working surface of the floor karst water damage ground area, which is provided by the embodiment of the invention, when the safety range of the treatment working surface is determined when a fault structure exists;

FIG. 5 is a third schematic view of the method for determining the safety range of the treatment working surface of the floor karst water damage ground area, which is provided by the embodiment of the invention, when the safety range of the treatment working surface is determined when a fault structure exists;

fig. 6 is a fourth schematic view of the method for determining the safety range of the treatment working surface of the floor karst water damage ground area, which is provided by the embodiment of the invention, when the safety range of the treatment working surface is determined when a fault structure exists.

In the figure, 1, a coal seam is mined, 2, a lower gate way, 3, an upper gate way, 4, an Ordovician ash layer, 5, an Ordovician ash top surface, 6, a first limit of the upper gate way, 7, a first limit of the lower gate way, 8, a second limit of the upper gate way, 9, a second limit of the lower gate way, and L, the width of a waterproof coal pillar.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1 to 6, a method for determining a safety range of a working surface for treating a ground area with karst water on a bottom plate according to the present invention will now be described. The method for determining the safety range of the control working surface of the floor karst water damage ground area is suitable for the North China coal fields. The coal mining working face of the coal field is a rectangular area enclosed by an upper crossheading 3, a lower crossheading 2, a cutting hole and a side hole, wherein the cutting hole is also called a main cutting hole, and the side hole is also called an auxiliary cutting hole.

Fig. 1 shows an implementation flow of a method for determining a safety range of a floor karst water damage ground area governance working surface according to an embodiment of the present invention, and the process is detailed as follows:

in step S100, analysis data of the mined coal seam 1 is acquired. The analytical data for the coal seam 1 is either a known quantity or a quantity that is experimentally available in the field.

In step S200, a waterproof pillar width calculation formula is obtained, which may be obtained through a self-created model or a known model, or may be derived from an existing model or formula.

In step S300, a waterproof pillar width L is obtained from the analytic data and the formula for waterproof pillar width L is a width extending along the coal seam in the direction of inclination on the mined coal seam 1.

In step S400, the limit is acquired. The method comprises the following steps: and S410, respectively acquiring a corresponding upper gate way first limit 6, a lower gate way first limit 7, a cutting eye first limit and a side eye first limit on the top surface of Ordovician limestone according to the width of the waterproof coal pillar.

Step S420, if there is a fault structure outside the upper gate 3 of the working surface (i.e. on the side of the upper gate 3 away from the lower gate 2), acquiring a second boundary 8 of the upper gate on the top surface of the austempered grey; if the outer part of the lower gate 2 of the working face (i.e. the side of the lower gate 2 far from the upper gate 3) has a fault structure, a second limit 9 of the lower gate is obtained on the top surface of the Ordovician grey; if the outer part of the cutting eye (namely the side of the cutting eye far away from the side eye) of the working surface has a fault structure, acquiring a second limit of the cutting eye on the top surface of Ordovician gray; if the outside of the side eye of the working surface (i.e. the side of the side eye away from the cutting eye) has a fault structure, a second limit of the side eye is obtained on the top surface of the gray.

In general, the first limit is related to the width of the waterproof coal pillar, and the second limit is related to the fault structure.

In step S500, an abatement working surface safety margin is obtained. The technical personnel in the field know that the range of the lime layer corresponding to the working face necessarily belongs to the safety range of the treatment working face, and the invention aims to further find out the treatment range of the upper crossheading outer working face, the treatment range of the lower crossheading outer working face, the treatment range of the cutting-hole outer working face and the treatment range of the side-hole outer working face.

The method comprises the following steps: if there is no fault structure outside the upper gate 3 of the working face, the upper gate first limit 6 is the upper gate outer limit. If the upper gate way 3 of the working face is provided with a fault structure, the part, which is relatively far away from the upper gate way 3, of the first boundary 6 and the second boundary 8 of the upper gate way is the final outer boundary of the upper gate way, so that the situation can be understood that the upper gate way first boundary 6 can obtain an upper gate way outer working face treatment range A after being determined, and the upper gate way second boundary 8 can obtain an upper gate way outer working face treatment range B after being determined, and the part, which is larger than the upper gate way outer working face treatment range A, of the upper gate way outer working face treatment range A and the upper gate way outer working face treatment range B is the final upper gate way outer working face treatment range.

For ease of understanding, fig. 3 and 4 show two examples of obtaining the outer boundary of the upper gateway on the top surface of the Ordovician Ash when a positive fault is present on the working surface outside the gateway 3. Referring to fig. 3, a normal fault is present on the working surface outside the gate 3 and the working surface is on the upper plate. At this point, an upper gateway first limit 6 and an upper gateway second limit 8 may be determined when the upper gateway treatment range is obtained. If the upper gateway second limit 8 is further away from the upper gateway 3 than the upper gateway first limit 6, then the upper gateway outer limit is the upper gateway second limit 8; if the upper gate second limit 8 is closer to the upper gate 3 than the upper gate first limit 6, then the upper gate outer limit is the upper gate first limit 6. Referring to fig. 4, a normal fault is present on the working surface outside the gate 3 and the working surface is located on the lower wall. At this point, an upper gateway first limit 6 and an upper gateway second limit 8 may be determined when the upper gateway treatment range is obtained. If the upper gateway second limit 8 is further away from the upper gateway 3 than the upper gateway first limit 6, then the upper gateway outer limit is the upper gateway second limit 8; if the upper gate second limit 8 is closer to the upper gate 3 than the upper gate first limit 6, then the upper gate outer limit is the upper gate first limit 6.

If there is no fault structure outside the lower gate 2 of the working face, the lower gate first limit 7 is the lower gate outer limit. If the lower crossheading 2 of the working face is provided with a fault structure, the one which is relatively far away from the lower crossheading 2 in the first boundary 7 and the second boundary 9 of the lower crossheading is the final outer boundary of the lower crossheading, so that the condition that the lower crossheading first boundary 7 is determined to obtain an outer working face treatment range A of the lower crossheading, and the lower crossheading second boundary 9 is determined to obtain an outer working face treatment range B of the lower crossheading, and the larger treatment range in the outer working face treatment range A of the lower crossheading and the outer working face treatment range B of the lower crossheading is the final outer working face treatment range of the lower crossheading.

For ease of understanding, fig. 5 and 6 are two examples of obtaining the upper gateway outer limit on the top surface of the Ordovician Ash when a normal fault exists outside the gateway 2 below the face. Referring to fig. 5, a normal fault is present outside the gate 2 below the working surface and the working surface is located on the lower wall. At this time, when the lower crossheading governing range is obtained, a lower crossheading first limit 7 and a lower crossheading second limit 9 can be determined. If the lower gateway second limit 9 is further away from the lower gateway 2 than the lower gateway first limit 7, then the lower gateway external limit is the lower gateway second limit 9; if the lower gateway second limit 9 is closer to the lower gateway 2 than the lower gateway first limit 7, then the lower gateway outer limit is the lower gateway first limit 7. Referring to fig. 6, a normal fault is present outside the gate 2 below the working surface and the working surface is on the upper plate. At this time, when the lower crossheading governing range is obtained, a lower crossheading first limit 7 and a lower crossheading second limit 9 can be determined. If the lower gateway second limit 9 is further away from the lower gateway 2 than the lower gateway first limit 7, then the lower gateway external limit is the lower gateway second limit 9; if the lower gateway second limit 9 is closer to the lower gateway 2 than the lower gateway first limit 7, then the lower gateway outer limit is the lower gateway first limit 7.

If the fault structure is not present outside the incision of the working surface, the first incision limit is used as the incision outer limit. If the outer part of the cutting eye of the working surface has a fault structure, the final outer cutting eye limit is the position relatively far away from the cutting eye in the first cutting eye limit and the second cutting eye limit, so that the condition that the first cutting eye limit is determined to obtain an outer cutting eye working surface treatment range A, the second cutting eye limit is determined to obtain an outer cutting eye working surface treatment range B, and the larger treatment range in the outer cutting eye working surface treatment range A and the outer cutting eye working surface treatment range B is the final outer cutting eye working surface treatment range.

If the fault structure is not present outside the side eye of the working surface, the side eye first limit is used as the side eye outside limit. If the outer side of the working face has a fault structure, the side eye far away from the first boundary of the side eye and the second boundary of the side eye relatively serves as a final outer side of the working face, so that the fact that the first boundary of the side eye can obtain an outer side of the working face control range A after the first boundary of the side eye is determined, and the second boundary of the side eye can obtain an outer side of the working face control range B after the second boundary of the side eye is determined can be understood, and the larger control range of the outer side of the working face control range A and the outer side of the working face control range B is the final outer side of the working face control range.

Finally, the range formed by the enclosing of the upper crossheading outer limit, the lower crossheading outer limit, the cutting eye outer limit and the side eye outer limit is the safety range of the treatment working face; namely, the control range of the upper crossheading outer working face, the control range of the lower crossheading outer working face, the control range of the outer cutting working face, the control range of the outer side-eye working face and the corresponding range of the austempered limestone layer of the original working face are the safety ranges of the control working faces.

It can be known from the above embodiments that the method for determining the safety range of the treatment working face of the floor karst water damage ground area provided by the embodiment of the present invention can obtain the boundary and finally determine the safety range of the treatment working face according to the analytic data of the mined coal seam, the waterproof pillar width calculation formula and the condition whether the related working face has the fault structure, thereby providing a guidance basis for the treatment work of the floor karst water damage ground area of the north China coal field.

As a specific embodiment of the method for determining the safety range of the treatment working face of the floor karst water damage ground area provided by the present invention, the step S100 of obtaining the analytic data of the mined coal seam 1 includes: and acquiring data such as water pressure borne by the lowest elevation of the coal seam floor, the thickness of the coal seam, the mining height of the coal seam, the tensile strength of coal, the critical water inrush coefficient and the like. The water pressure borne by the lowest elevation of the coal seam floor is calculated according to the top surface of Ordovician limestone by a water inrush coefficient method, and the water level elevation is calculated according to the highest water level of an Ordovician limestone aquifer in nearly 3 years.

As a specific embodiment of the method for determining the safety range of the treatment working surface of the floor karst water damage ground area, provided by the invention, the waterproof coal pillar width calculation formula is as follows:

wherein L is waterproof coal pillar width, and K is factor of safety, and M is the great value in coal seam thickness and coal seam height, and P is the water pressure that the minimum elevation of coal seam bottom plate bore, and K is_PIs the tensile strength, T, of coal_SThe critical water inrush coefficient is L with the unit of M, M with the unit of M, K_PAnd P has units of MPa, T_SThe unit of (b) is MPa/m. K is a unitless coefficient which can be obtained empirically and generally ranges from 4 to 7.

It should be noted that, because parameters such as the water pressure borne by the lowest elevation of the coal seam floor at the positions of the upper gate way, the lower gate way, the cutting hole and the side hole may have different values, the widths of the waterproof coal pillars of the upper gate way, the lower gate way, the cutting hole and the side hole may also be different.

The formula of the waterproof coal pillar width calculation formula is derived from two formulas in coal mine prevention and control water rules, and the two formulas are divided into two formulas in appendix six of coal mine prevention and control water rules:

and the two water inrush coefficient method formulas in annex five of the coal mine water control regulations:

wherein L' is the first estimated width of the waterproof coal pillar, and L "is the second estimated width of the waterproof coal pillar.

The first estimated waterproof coal pillar width and the second estimated waterproof coal pillar width are estimated waterproof coal pillar widths obtained by using different models respectively, and the waterproof coal pillar width is finally a larger value of the first estimated waterproof coal pillar width and the second estimated waterproof coal pillar width, so that a safer width is obtained.

As a specific embodiment of the method for determining the safety range of the governing working face of the floor karst water damage ground area, provided by the invention, the value of the safety coefficient is 5. After multiple verification, the safety factor is more suitable to be 5, and the safety range of the treatment working surface which is safer and not too large can be obtained.

As a specific embodiment of the method for determining the safety range of the governing working face of the floor karst water damage ground area, the value of the critical water inrush coefficient is 0.06MPa/m according to experience.

Referring to fig. 2 to 6, as an embodiment of the method for determining the safety range of the treatment working surface of the floor karst water damage ground area provided by the present invention, the step S400 of obtaining the first upper crossheading limit 6 on the top surface of the aoai includes taking the lowest elevation of the floor of the coal seam of the above crossheading 3 as a starting point, translating the waterproof coal pillar by a width L outwards along the coal seam inclination direction (i.e. upwards along the coal seam inclination direction), and then obtaining an intersection line intersecting the aoai top surface 5 along the normal direction of the rock formation, and taking the intersection line as the first upper crossheading limit 6.

Referring to fig. 2 to 6, as a specific embodiment of the method for determining the safety range of the treatment working surface of the floor karst water damage ground area provided by the present invention, the step S400 of obtaining the first lower crossheading limit 7 on the top surface of the aoai includes taking the lowest elevation of the floor of the coal seam of the following crossheading 2 as a starting point, translating the waterproof coal pillar by a width L outwards along the coal seam inclination direction (i.e., downwards along the coal seam inclination direction), and projecting the waterproof coal pillar to the aoai top surface 5 along the vertical direction to obtain a projection line on the top surface of the aoai at that time, and taking the projection line as the first lower crossheading limit 7.

As a specific embodiment of the method for determining the safety range of the governing working face of the floor karst water damage ground area, the step S400 of obtaining the first cut-off limit of the top surface of the Ordovician limestone comprises the steps of taking the lowest elevation of the floor of the coal seam of the cut-off limit as a starting point, translating the coal seam outwards along the coal seam trend direction (namely along the coal seam trend towards the direction far away from the edge eye) by the width L of the waterproof coal pillar, then projecting the coal seam outwards along the vertical direction to the top surface 5 of the Ordovician limestone, obtaining the projection line on the top surface of the Ordovician limestone at the moment, and taking the projection line as the first cut-off limit.

As a specific embodiment of the method for determining the safety range of the governing working face of the floor karst water damage ground area, the step S400 of obtaining the first boundary of the side eye on the top surface of the Ordovician limestone comprises the steps of taking the lowest elevation of the floor of the coal seam of the side eye as a starting point, translating the distance of the width L of the waterproof coal pillar outwards along the coal seam trend direction (namely, along the coal seam trend towards the direction far away from the cutting eye), then projecting the waterproof coal pillar to the top surface 5 of the Ordovician limestone along the vertical direction, obtaining the projection line on the top surface of the Ordovician limestone at the moment, and taking the projection line as the first boundary of the side eye.

Referring to fig. 3 to 4, as an embodiment of the method for determining the safety range of the floor area harnessing the karst water damage of the floor area provided by the present invention, in step S500, if the outer portion of the upper gate way 3 of the floor area (i.e. the side of the upper gate way 3 away from the lower gate way 2) has a fault structure, the method obtains the second limit 8 of the upper gate way on the top surface of the austempered limestone, which specifically includes:

and an outer side intersection line of the fault plane and the Ordovician gray top surface 5 (the fault plane and the Ordovician gray top surface 5 have two intersection lines, and the outer side intersection line is the intersection line far away from the upper crossheading 3) is taken as a vertical plane, and the second limit 8 of the upper crossheading is the intersection line of the vertical plane and the Ordovician gray top surface 5 after the vertical plane is horizontally moved outwards (namely the direction of one side of the upper crossheading 3 far away from the lower crossheading 2) by a first preset length.

Referring to fig. 5 to 6, as an embodiment of the method for determining the safety range of the floor surface for treating the ground area with the karst water damage of the floor provided by the present invention, in step S500, if the outside of the lower gate 2 of the floor surface (i.e. the side of the lower gate 2 away from the upper gate 3) has a fault structure, the method obtains the second limit 9 of the lower gate on the top surface of the austempered limestone, which specifically includes:

the outer side intersection line of the fault plane and the Ordovician gray top surface 5 (the fault plane and the Ordovician gray top surface 5 have two intersection lines, and the outer side intersection line is the intersection line far away from the lower crossheading 2) is taken as a vertical plane, and the second limit 9 of the lower crossheading is the intersection line of the vertical plane and the Ordovician gray top surface 5 after the vertical plane is horizontally moved outwards (namely the direction of one side of the lower crossheading 2 far away from the upper crossheading 3) by a second preset length.

As a specific embodiment of the method for determining the safety range of the floor surface for treating the ground area with karst water damage on the floor provided by the present invention, in step S500, if there is a fault structure outside the cutting hole (i.e. in a direction of a side of the cutting hole far from the edge hole) of the floor surface, the method obtains a second limit of the cutting hole on the top surface of aogrey, and specifically includes:

the outer side intersecting line of the fault plane and the Ordovician grey top surface 5 (the fault plane and the Ordovician grey top surface 5 have two intersecting lines, and the outer side intersecting line is the intersecting line far away from the cutting hole) is used as a vertical plane, and the second limit of the cutting hole is the intersecting line of the vertical plane and the Ordovician grey top surface 5 after the vertical plane is horizontally moved outwards (namely the direction of the cutting hole far away from the side hole) by a third preset length.

As a specific embodiment of the method for determining the safety range of the floor surface for treating the ground area with karst water damage on the floor provided by the present invention, in step S500, if there is a fault structure outside the side eye of the floor surface (i.e. in a direction of the side eye away from the cutting hole), the method obtains a second limit of the side eye on the top surface of the Ordovician gray, and specifically includes:

the outer side intersecting line of the fault plane and the Ordovician gray top surface 5 (the fault plane and the Ordovician gray top surface 5 have two intersecting lines, and the outer side intersecting line is the intersecting line far away from the side eye) is used as a vertical plane, and the second limit of the side eye is the intersecting line of the vertical plane and the Ordovician gray top surface 5 after the vertical plane is horizontally moved outwards (namely the side direction of the side eye far away from the cutting eye) by a fourth preset length.

According to a specific embodiment of the method for determining the safety range of the governing working surface of the floor karst water damage ground area, according to experience, a first preset length is greater than or equal to 50m, a second preset length is greater than or equal to 50m, a third preset length is greater than or equal to 50m, and a fourth preset length is greater than or equal to 50 m.

Referring to fig. 3 to 6, as an embodiment of the method for determining the safety range of the working surface for treating the ground area with the karst water on the bottom plate according to the present invention, according to experience, the first preset length is equal to 50m, the second preset length is equal to 50m, the third preset length is equal to 50m, and the fourth preset length is equal to 50 m.

As a specific embodiment of the method for determining the safety range of the floor karst water damage ground area governing working face provided by the invention, if the working face is arranged along the goaf, repeated overlapping mining damage is considered, and the minimum safety governing range on one side of the goaf of the working face is not less than 1.5 times of the hole distance of the branch governing holes of the area.

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 and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.