CN113982581A - Stability control method for overburden seepage isolation zone based on low-carbon mining - Google Patents
Stability control method for overburden seepage isolation zone based on low-carbon mining Download PDFInfo
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Abstract
The invention discloses a stability control method for a overburden seepage isolation zone based on low-carbon mining, and relates to the technical field of coal mining. Firstly, constructing a overburden seepage isolation zone classification system based on the permeability of the seepage isolation zone and a space layer; then, providing a wall type continuous mining and continuous filling working face arrangement mode and mining parameters based on the stability classification control of the seepage isolation belt structure; filling materials capable of keeping stable bearing under the conditions of different working face arrangement modes and mining parameters are selected; and finally, judging whether the seepage isolation zone is broken or not, and if the seepage isolation zone is broken, adjusting the wall type continuous mining and continuous filling mining parameters or the working face arrangement mode. The method can realize the in-situ protection of the water-containing body on the ecological fragile mining area, and is beneficial to the construction of ecological mines and green mines.
Description
Technical Field
The invention relates to a stability control method for a overburden seepage isolation zone, in particular to a stability control method for a low-carbon mining-based overburden seepage isolation zone, which is suitable for an overburden seepage isolation zone area.
Background
The amount of the pressed coal under the surface water body and the underground water-bearing layer in China is huge, and how to realize the coordinated development between the safe and efficient exploitation of coal resources and the protection of precious water resources is a problem which needs to be solved urgently at present. At present, researchers mostly take whether a water flowing fractured zone develops to an overlying water-bearing body as a main criterion and criterion for realizing water retention coal mining, and neglect the seepage isolation effect of different overlying rock lithologies and space horizons on the overlying water-bearing body. In order to realize the seepage isolation of the weak seepage isolation belt to the overlying water-containing body, related experts propose and practice coal mining methods such as coordinated mining, overlying strata separation layer grouting, partial mining, goaf filling mining and the like, wherein the goaf filling coal mining method is the most effective way for realizing the seepage isolation of the weak seepage isolation belt to the overlying water-containing body and further realizing water-retaining coal mining. The goaf filling mining is mainly divided into longwall filling mining and roadway filling mining. However, longwall filling mining faces the problems of insufficient filling time and space and mutual limitation of mining and filling, and roadway filling mining faces the problems of low mining efficiency and the like. The modernized mining of mines requires that the water-retaining coal mining technology must simultaneously realize safe and efficient mining and in-situ protection of overlying water bodies.
Disclosure of Invention
Aiming at the prior art, the stability control method of the overburden seepage isolation zone based on low-carbon mining is provided, which has simple steps, combines the advantages of roadway-type jump mining and Wangeviry mining, realizes continuous coal mining and continuous filling, and furthest mines coal resources.
In order to achieve the technical purpose, the stability control method of the overburden seepage isolation zone based on low-carbon mining comprises the following steps:
constructing a overburden seepage isolation zone classification system based on permeability coefficients and space horizons, wherein the overburden seepage isolation zone classification system specifically comprises four types which are combined and divided according to the permeability coefficients and rock strata, three types which are divided according to the horizons according to seepage, and 12 types of overburden seepage isolation zones in total;
step two, according to the type of the current overburden seepage isolation zone, aiming at a working face, implementing a wall type continuous mining continuous filling working face arrangement method based on classification control of the stability of the mining overburden seepage isolation zone, wherein the wall type continuous mining continuous filling working face arrangement method comprises two arrangement methods: firstly, mining and filling a working face by adopting a roadway-type jump mining method, and then mining a Wangeviry block section; or adopting a mode of completely not leaving isolated coal pillars between the Wangeviry mining blocks, and carrying out jump mining filling on the mining blocks;
step three, selecting a filling material meeting the support requirement or adjusting the formula of the filling material according to the wall type continuous mining and continuous filling working face arrangement method selected in the step two;
and step four, judging whether the overburden seepage isolation belt of the current working face is broken under the construction of the selected wall type continuous mining and continuous charging working face arrangement method, if not, continuing to implement the construction, realizing the water resource protective mining, if so, adjusting mining parameters, and if adjusting the mining parameters, still breaking, replacing the working face arrangement mode.
In the first step, the method can be divided into the following steps according to the combination of permeability coefficient and rock stratum: i type seepage isolation zone: single weak rock stratum with permeability coefficient less than 10-7m/s; II type seepage isolation zone: a single hard rock layer, namely a structural key layer, the uniaxial compressive strength is more than 60MPa, and the permeability coefficient is less than 10-4m/s; III class seepage isolation zone: soft rock and hard rock combination rock strata; IV type seepage isolation belt: permeability coefficient greater than 10-1m/s, the confined expansion rate is more than 40%, and the thickness meets the formula (1).
Wherein gamma is the specific gravity of water; b isiThe width of the primary fracture; μ is the dynamic viscosity coefficient of the water body, μ =0.839e at 25 °-3Pa·s；Delta is the confined expansion ratio; j is hydraulic gradient; theta is the included angle between the primary fracture and the horizontal line of the seepage isolation zone; dsIs the fracture spacing; mminThe minimum thickness of the IV-class seepage isolation zone;
the four types of seepage isolation zones can be further divided into the following parts according to the layer positions: high-level seepage isolation zone: hs>Hf(ii) a A middle position seepage isolation zone: hc≤Hs≤Hf(ii) a ③ low-position seepage isolation zone: hs＜Hc(ii) a Wherein HsIs a seepage isolation zone layer position; hcThe height of the longwall landing zone; hfThe height of the water flowing fractured zone of the long wall is high.
In four types of overburden seepage isolation zones divided according to permeability coefficients and rock stratum combinations, the capacity of realizing seepage isolation of upper water-containing bodies is as follows: class III > class I > class II > class IV; in the three types of overburden seepage isolation zones divided according to the layer positions according to seepage, the capacity of realizing seepage isolation of the water-containing body at the upper part is as follows: high order > medium order > low order.
The class 12 vadose zone is divided into: 4 strong seepage isolation zones, wherein the seepage isolation capability is greater than that of the IV-class seepage isolation zone at the high layer; 5 weak seepage isolation zones, wherein the seepage isolation capability is smaller than that of the IV-class seepage isolation zone at the middle layer; 3 medium seepage isolation zones.
In the second step, the arrangement mode of the wall type continuous mining and continuous filling working face specifically comprises 2 types: firstly, aiming at a strong seepage isolation zone, improving the original Wangeviry mining method, mining and filling the original isolation coal pillar (protection block) by adopting a roadway type jump mining method, and then mining the Wangeviry block (mining block); and the mining parameters satisfy the formula (2); and secondly, aiming at the medium and weak seepage isolation zones, improving the original WangGeviry coal mining method, completely leaving no isolation coal pillars between WangGeviry mining blocks, and performing jump mining filling on the mining blocks.
Nd2＜2lsinα+d1 (2)
Wherein N is the number of the protection block section supporting lanes, N is more than or equal to 1, and N is an integer; d2The width of a branch roadway of the protective block section; l is the length of the mining block section underground mining; d1The length of a branch roadway of the mining block section; alpha is an included angle between a mining block branch roadway and a mining cave.
And in the third step, the critical strength of the filling body for maintaining the bearing stability is obtained according to the stress characteristics of the filling body, and the strength of the filling material needs to meet the formula (3).
Wherein, PmaxIs the maximum load of the filling body, MPa; h is the coal seam buried depth m; lambda is a safety factor; less than or equal tocThe uniaxial compressive strength of the filling body measured in a laboratory is MPa; m is the coal seam mining height M; w is the width of the filling body in the wall type continuous mining and continuous filling, m.
And in the fourth step, judging whether the seepage isolation zone is broken or not by adopting a formula (4).
In the formula (I), the compound is shown in the specification,
maximum tensile stress of the rock stratum of the seepage isolation zone; hsIn order to isolate the thickness of the formation in the zone for seepage,
the maximum bending moment of the rock stratum of the seepage isolation zone is set;
allowing tensile stress for the formation of the seepage isolation zone.
Aiming at the broken strong seepage isolation zone, adjusting the wall type continuous mining and continuous filling mining parameters: increasing number of lanes N of protection block and reducing width d of lanes of protection block2(ii) a ② the length l of the Wangeviry mining block mining cave and the width d of the branch roadway are reduced1(ii) a ③ to Nd2≥2lsinα+d1When in use, the working face arrangement mode below the medium seepage intensity is adopted.
Aiming at the broken seepage isolation zone with medium and weak seepage isolation strength, the filling rate of the filling body is continuously improved until full mining and full filling.
Has the advantages that:
on the basis of constructing a classification system of the overburden seepage isolation belt, the method specifically selects different wall type continuous mining continuous filling working face arrangement modes and mining parameters, adopts filling materials to carry out full mining and partial filling or full mining and non-filling, and can realize classification cooperative control of the stability of the overburden seepage isolation belt of mining while reducing the filling cost to the maximum extent. The seepage isolation zones are divided into 12 types in detail, so that workers can judge according to specific hydrogeological conditions, and mine construction is guided better. The method realizes seepage isolation and in-situ protection of the overlying water-bearing body while safely and efficiently liberating the pressing coal under the water-bearing body, and is favorable for promoting the construction of ecological mines and green mines.
Drawings
FIG. 1 is a schematic flow chart of a stability control method of a overburden seepage isolation zone based on low-carbon mining, provided by the invention;
FIG. 2 is a schematic diagram of the arrangement of the wall-type continuous mining and continuous charging working face of the strong seepage isolation zone in the present embodiment;
FIG. 3 is a schematic diagram of the arrangement of the wall-type continuous mining continuous-filling working face in the present embodiment when the filling rate of the medium and weak seepage isolation zone is low;
FIG. 4 is a schematic diagram of the arrangement of the wall-type continuous mining continuous-filling working face in the present embodiment when the filling rate of the medium and weak seepage isolation zones is high;
FIG. 5 is a comprehensive geological histogram of a wall-type continuous mining and filling test block in this embodiment.
In the figure: 1-mining a block section underground mining; 2-mining small coal pillars between the block mining chambers; 3-mining a block branch roadway; 4-protecting block section branch lane; 5-the mining block section is filled and mined; 6-the mining block is filled with branch roadway.
Detailed Description
The following is a brief description of embodiments of the invention, taken in conjunction with the accompanying drawings:
as shown in figure 1, the stability control method for the overburden seepage isolation zone based on low-carbon mining is characterized by comprising the following steps of:
constructing a overburden seepage isolation zone classification system based on permeability coefficients and space horizons, wherein the overburden seepage isolation zone classification system specifically comprises four types which are combined and divided according to the permeability coefficients and rock strata, three types which are divided according to the horizons according to seepage, and 12 types of overburden seepage isolation zones in total;
the permeability coefficient and the formation composition can be divided into: i type seepage isolation zone: single weak rock stratum with permeability coefficient less than 10-7m/s; II type seepage isolation zone: a single hard rock layer, namely a structural key layer, the uniaxial compressive strength is more than 60MPa, and the permeability coefficient is less than 10-4m/s; III class seepage isolation zone: soft rock and hard rock combination rock strata; IV type seepage isolation belt: permeability coefficient greater than 10-1m/s, the confined expansion rate is more than 40%, and the thickness meets the formula (1).
Wherein gamma is the specific gravity of water; b isiThe width of the primary fracture; mu is dynamic viscosity coefficient of water body, and at 25 deg. mu is 0.839e-3Pa · s; delta is the confined expansion ratio; j is hydraulic gradient; theta is the included angle between the primary fracture and the horizontal line of the seepage isolation zone; dsIs the fracture spacing; mminThe minimum thickness of the IV-class seepage isolation zone;
the four types of seepage isolation zones can be further divided into the following parts according to the layer positions: high-level seepage isolation zone: hs＞Hf(ii) a A middle position seepage isolation zone: hc≤Hs≤Hf(ii) a ③ low-position seepage isolation zone: hs＜Hc(ii) a Wherein HsIs a seepage isolation zone layer position; hcThe height of the longwall landing zone; hfThe height of the longwall water-flowing fractured zone is high;
in four types of overburden seepage isolation zones divided according to permeability coefficients and rock stratum combinations, the capacity of realizing seepage isolation of upper water-containing bodies is as follows: class III > class I > class II > class IV; in the three types of overburden seepage isolation zones divided according to the layer positions according to seepage, the capacity of realizing seepage isolation of the water-containing body at the upper part is as follows: high order > medium order > low order;
the class 12 vadose zone is divided into: 4 strong seepage isolation zones, wherein the seepage isolation capability is greater than that of the IV-class seepage isolation zone at the high layer; 5 weak seepage isolation zones, wherein the seepage isolation capability is smaller than that of the IV-class seepage isolation zone at the middle layer; 3 medium seepage isolation zones;
step two, according to the type of the current overburden seepage isolation zone, aiming at a working face, implementing a wall type continuous mining continuous filling working face arrangement method based on classification control of the stability of the mining overburden seepage isolation zone, wherein the wall type continuous mining continuous filling working face arrangement method comprises two arrangement methods: firstly, mining and filling a working face by adopting a roadway-type jump mining method, and then mining a Wangeviry block section; or adopting a mode of completely not leaving isolated coal pillars between the Wangeviry mining blocks, and carrying out jump mining filling on the mining blocks;
the arrangement mode of the wall type continuous mining and continuous charging working face specifically comprises 2 types: firstly, aiming at a strong seepage isolation zone, improving the original Wangeviry mining method, mining and filling the original isolation coal pillar (protection block) by adopting a roadway type jump mining method, and then mining the Wangeviry block (mining block); and the mining parameters satisfy the formula (2); and secondly, aiming at the medium and weak seepage isolation zones, improving the original WangGeviry coal mining method, completely leaving no isolation coal pillars between WangGeviry mining blocks, and performing jump mining filling on the mining blocks.
Nd2＜2lsinα+d1 (2)
Wherein N is the number of the protection block section supporting lanes, N is more than or equal to 1, and N is an integer; d2The width of the branch lane 4 for the protection block section; l is the length of the mining block section underground mining 1; d1The length of the branch roadway 3 for the mining block section; alpha is an included angle between the mining block branch roadway 3 and the mining block underground mining 1;
step three, selecting a filling material meeting the support requirement or adjusting the formula of the filling material according to the wall type continuous mining and continuous filling working face arrangement method selected in the step two;
obtaining the critical strength of the filling body for maintaining the bearing stability according to the stress characteristics of the filling body, wherein the strength of the filling material needs to satisfy the formula (3):
wherein, PmaxIs the maximum load of the filling body; h is the coal seam burial depth; lambda is a safety factor; sigmacThe uniaxial compressive strength of the filling body measured in a laboratory is MPa; m is the coal seam mining height; w is the width of the filling body in the wall type continuous mining and continuous filling process;
judging whether the overburden seepage isolation belt of the current working face is broken under the construction of the selected wall type continuous mining and continuous charging working face arrangement method, if not, continuing to implement to realize the water resource protective mining, if so, adjusting mining parameters, and if adjusting the mining parameters, still breaking, replacing the working face arrangement mode;
judging whether the seepage isolation zone is broken or not by adopting a formula (4):
in the formula (I), the compound is shown in the specification,
maximum tensile stress of the rock stratum of the seepage isolation zone; hsIn order to isolate the thickness of the formation in the zone for seepage,
the maximum bending moment of the rock stratum of the seepage isolation zone is set;
allowing tensile stress for the formation of the seepage isolation zone.
Aiming at the broken strong seepage isolation zone, adjusting the wall type continuous mining and continuous filling mining parameters: increasing number of lanes N of protection block and reducing width d of lane 42(ii) a Increasing the width of the small coal pillar 2 between the mining block mining chambers, and simultaneously reducing the length l of the Wangeviry mining block mining chamber 1 and the width d of the mining block branch roadway 31(ii) a ③ to Nd2≥2lsinα+d1When in use, the working face arrangement mode below the medium seepage intensity is adopted.
Aiming at the broken seepage isolation zone with medium and weak seepage isolation strength, the filling rate of the filling body is continuously improved until full mining and full filling.
The first embodiment,
A flow chart of a stability control method of a overburden seepage isolation zone based on low-carbon mining is known, and the cooperative control method mainly comprises the following steps:
firstly, constructing a overburden seepage isolation zone classification system based on permeability coefficients and a space horizon. Overburden vadose zones can be classified into 12 categories. The permeability coefficient and the formation composition can be divided into: i type seepage isolation zone: single weak rock stratum with permeability coefficient less than 10-7m/s; II type seepage isolation zone: single hard rock stratum (structural key layer), uniaxial compressive strength of more than 60MPa and permeability coefficient of less than 10-4m/s; III class seepage isolation zone: soft rock and hard rock combination rock strata; IV type seepage isolation belt: permeability coefficient greater than 10-1m/s, the confined expansion rate is more than 40%, and the thickness meets the formula (1).
Wherein gamma is the specific gravity of water; b isiIs the native fracture width, m; mu is dynamic viscosity coefficient of water body (mu is 0.839e at 25 DEG)-3Pa · s); δ is the confined expansion ratio,%; j is hydraulic gradient; theta is the included angle between the primary crack and the horizontal line of the seepage isolation zone; dsIs the crack spacing, m; mminThe minimum thickness of the IV-type seepage isolation zone is m.
The capacity of realizing seepage isolation of the upper water-containing body is as follows: class III > class I > class II > class IV.
The above 4 kinds of seepage isolation zones can be divided into: high-level seepage isolation zone: hs＞Hf(ii) a A middle position seepage isolation zone: hc≤Hs≤Hf(ii) a ③ low-position seepage isolation zone: hs＜Hc. See in particular the table below.
Wherein HsRepresenting a seepage isolation zone horizon; sigma M represents the cumulative mining height
The capacity of realizing seepage isolation of the upper water-containing body is as follows: high order > medium order > low order.
The above class 12 vadose isolation zone can be roughly divided into: 4 strong seepage isolation zones (the seepage isolation capability is higher than that of the IV-class seepage isolation zone at the high layer), 5 weak seepage isolation zones (the seepage isolation capability is lower than that of the IV-class seepage isolation zone at the middle layer) and 3 medium seepage isolation zones.
And secondly, providing a wall type continuous mining and continuous filling working face arrangement mode based on classification control of stability of the mining overburden seepage isolation belt structure. The arrangement mode of the wall type continuous mining and continuous charging working face comprises 2 types: firstly, aiming at a strong seepage isolation zone, as shown in figure 2, the original Wanggervey mining method is improved, the original isolation coal pillar (a protection block section is filled into a branch roadway) is mined and filled by adopting a roadway-type jump mining method, and the number of the protection block section is B1，B2，…，BnAnd then mining the Wangeviry block (mining block) with the number M1，M2，…，Mn(ii) a And the mining parameters satisfy the formula (2):
Nd2＜2lsinα+d1 (2)
wherein N is the number of the protection block section supporting lanes (N is not less than 1 and is an integer), and N is an integer; d2The width m of the protection block section branch lane 4; l is the length of the mining block section underground mining 1, m; d1The length of the mining block branch roadway 3 is m; alpha is the included angle between the mining block branch roadway 3 and the mining block underground mining 1.
As shown in FIG. 3, for medium and weak percolation barrier zones, the width of the protection block needs to be increased because the percolation barrier zone is weaker than the strong percolation barrier zone, and when the width of the protection block is greater than or equal to the width of the mining block, namely Nd2≥2lsinα+d1And meanwhile, the original WangGeviry coal mining method is improved, the protection block sections are completely replaced by WangGeviry mining block sections, and isolation coal pillars are not left between the mining block sections. At this time, the whole mining area has n Wangeviry cutSampling block segment, marked as M1，M2，…，MnJumping mining is carried out on the mining block section, and the mining block section mining cave 1 and the mining block section branch roadway 3 of the (2m-1) th Wangeviry block section after mining are filled to form a mining block section filled mining cave 5 and a mining block section filled branch roadway 6, and the 2m mining block section mining cave 1 and the mining block section branch roadway 3 are not filled.
As shown in FIG. 4, if the water blocking capability of the seepage isolation is further weakened, the (3m-2) th and (3m-1) th mining blocks are filled, and the 3m mining block is not filled, wherein m is an integer, m is more than or equal to 1 and less than or equal to n/3, and n is a multiple of 3. Obviously, for the seepage isolation zone with the weakest seepage isolation capability, all the Wangeviry mining blocks need to be fully mined and fully charged.
And thirdly, selecting filling materials under different mining and filling conditions, and specifically comprising the following steps: acquiring the critical strength of the filling body for maintaining the bearing stability according to the stress characteristics of the filling body; selecting filling material to make laboratory uniaxial compression strength sigma of filling materialcAnd maximum load P of the packing bodymaxSatisfying formula (3).
Wherein, PmaxIs the maximum load of the filling body, MPa; h is the coal seam buried depth m; lambda is a safety factor; sigmacThe uniaxial compressive strength of the filling body measured in a laboratory is MPa; m is the coal seam mining height M; w is the width of the filling body in the wall type continuous mining and continuous filling, m.
And fourthly, judging whether the overburden seepage isolation belt is broken under the conditions of different working face arrangement modes by adopting a formula (4).
In the formula (I), the compound is shown in the specification,
maximum tensile stress of formation for seepage isolation zone；HsIn order to isolate the thickness of the formation in the zone for seepage,
the maximum bending moment of the rock stratum of the seepage isolation zone is set;
allowing tensile stress for the formation of the seepage isolation zone.
Further, aiming at the broken strong seepage isolation belt, adjusting the wall type continuous mining and continuous filling mining parameters: increasing number of lanes N of protection block and reducing width d of lane 42(ii) a Increasing the width of the small coal pillar 2 between the mining block mining chambers, and simultaneously reducing the length l of the Wangeviry mining block mining chamber 1 and the width d of the mining block branch roadway 31(ii) a ③ to Nd2≥2lsinα+d1When in use, the working face arrangement mode below the medium seepage intensity is adopted.
Furthermore, aiming at the broken medium and weak seepage isolation zones, the filling rate of the filling body is continuously improved until full mining and full filling.
Example 1: this example takes a particular mine in Shanxi. The main mining coal seam of the mine is 15 coals, the thickness of the coal seam is 2.5m, the inclination angle is 1-3 degrees, as shown in figure 5, the average buried depth of the coal seam is 250m, different layers of the upper part of a mining block section are provided with a sandstone aquifer (I) and a sandstone aquifer (II), and the lower parts of the two aquifers are provided with III-type seepage isolation zones. If water-retaining coal mining is to be realized, the seepage isolation of the lower seepage isolation zone to the aquifer (II) must be ensured, and the distance between the lower overburden seepage isolation zone and the coal seam roof is 16 m. The covering rock of the mining block section mainly comprises fine sandstone, sandy mudstone, limestone and the like, and the integral lithology of the covering rock is medium-hard. The height of the longwall caving zone is 17.5m and the height of the water-flowing fractured zone is 41.6 m. According to the classification system standard of the seepage isolation zone, the III-class seepage isolation zone close to the coal bed belongs to a weak seepage isolation zone. The pressed coal under water is liberated by adopting the arrangement mode of a wall type continuous mining and continuous filling working face as shown in figure 4. The length of the mining block section underground mining is 10m, the width of the branch roadway is 5.5m, the included angle alpha between the branch roadway and the underground mining is 40 degrees, and the full mining and full filling are realized. The average length of the mining block is 340m, and the width of the mining block is about 150 m. According to the subordinate area method and the Sheorey coal pillar strength calculation formula, the bearing stability of the filling body can be ensured when the strength and the stress of the filling body meet the formula (5):
wherein gamma is the average volume weight of overlying strata, and 2.5 × 10 is taken-2MPa/m, H is the coal seam buried depth, 250m is taken, lambda is the safety coefficient, 2.7, sigma is takencThe uniaxial compressive strength of the filling body measured in a laboratory is determined, wherein M is the mining height of the coal bed and is 2.5M, and W is 4lsin alpha +2d1The minimum uniaxial compressive strength of the filler measured in the laboratory must be more than 1.4MPa after being 4X 10 Xsin 35 DEG + 2X 5.5 ═ 33.8 m. Selecting the filling material according to the key mechanical parameter index.
And (3) establishing a mining overburden rock deformation elastic foundation beam mechanical model according to the wall type continuous mining and continuous filling working face arrangement mode shown in the figure 4 to obtain a roof arbitrary rock stratum deflection formula. Calculating the maximum tensile stress of the lower III-class seepage isolation zone (weak seepage isolation zone) according to a deflection formula
The sufficient condition for keeping the structure of the seepage isolation belt stable is that
And (3) introducing specific numerical values to obtain that the thin sandstone stratum with the thickness of 37m at the lower part of the lower III-class seepage isolation zone is not broken, and the seepage isolation zone still has the seepage isolation effect on the aquifer (II) at the upper part of the seepage isolation zone.
Claims (7)
1. A stability control method for a overburden seepage isolation zone based on low-carbon mining is characterized by comprising the following steps:
constructing a overburden seepage isolation zone classification system based on permeability coefficients and space horizons, wherein the overburden seepage isolation zone classification system specifically comprises four types which are combined and divided according to the permeability coefficients and rock strata, three types which are divided according to the horizons according to seepage, and 12 types of overburden seepage isolation zones in total;
step two, according to the type of the current overburden seepage isolation zone, aiming at a working face, implementing a wall type continuous mining continuous filling working face arrangement method based on classification control of the stability of the mining overburden seepage isolation zone, wherein the wall type continuous mining continuous filling working face arrangement method comprises two arrangement methods: firstly, mining and filling a working face by adopting a roadway-type jump mining method, and then mining a Wangeviry block section; or adopting a mode of completely not leaving isolated coal pillars between the Wangeviry mining blocks, and carrying out jump mining filling on the mining blocks;
step three, selecting a filling material meeting the support requirement or adjusting the formula of the filling material according to the wall type continuous mining and continuous filling working face arrangement method selected in the step two;
and step four, judging whether the overburden seepage isolation belt of the current working face is broken under the construction of the selected wall type continuous mining and continuous charging working face arrangement method, if not, continuing to implement the construction, realizing the water resource protective mining, if so, adjusting mining parameters, and if adjusting the mining parameters, still breaking, replacing the working face arrangement mode.
2. The method for controlling the stability of the overburden seepage isolation zone based on the low carbon mining as claimed in claim 1, wherein in the step one, the method can be divided into the following steps according to the combination of permeability coefficients and rock strata: i type seepage isolation zone: single weak rock stratum with permeability coefficient less than 10-7m/s; II type seepage isolation zone: a single hard rock layer, namely a structural key layer, the uniaxial compressive strength is more than 60MPa, and the permeability coefficient is less than 10-4m/s; III class seepage isolation zone: soft rock and hard rock combination rock strata; IV type seepage isolation belt: permeability coefficient greater than 10-1m/s, the confined expansion rate is more than 40 percent, and the thickness meets the formula (1),
wherein gamma is the specific gravity of water; b isiThe width of the primary fracture; mu is dynamic viscosity coefficient of water body, and at 25 deg. mu is 0.839e-3Pa · s; delta is the confined expansion ratio; j is hydraulic gradient; horizontal line clamp for theta as primary crack and seepage isolation zoneAngle °; dsIs the fracture spacing; mminThe minimum thickness of the IV-class seepage isolation zone;
the four types of seepage isolation zones can be further divided into the following parts according to the layer positions: high-level seepage isolation zone: hs＞Hf(ii) a A middle position seepage isolation zone: hc≤Hs≤Hf(ii) a ③ low-position seepage isolation zone: hs＜Hc(ii) a Wherein HsIs a seepage isolation zone layer position; hcThe height of the longwall landing zone; hfThe height of the water flowing fractured zone of the long wall is high.
3. The overburden seepage isolation zone stability control method based on low carbon mining of claim 2, wherein: in four types of overburden seepage isolation zones divided according to permeability coefficients and rock stratum combinations, the capacity of realizing seepage isolation of upper water-containing bodies is as follows: class III > class I > class II > class IV; in the three types of overburden seepage isolation zones divided according to the layer positions according to seepage, the capacity of realizing seepage isolation of the water-containing body at the upper part is as follows: high order > medium order > low order.
4. The overburden seepage isolation zone stability control method based on low carbon mining of claim 1, wherein: the class 12 vadose zone is divided into: 4 strong seepage isolation zones, wherein the seepage isolation capability is greater than that of the IV-class seepage isolation zone at the high layer; 5 weak seepage isolation zones, wherein the seepage isolation capability is smaller than that of the IV-class seepage isolation zone at the middle layer; 3 medium seepage isolation zones.
5. The overburden seepage isolation zone stability control method based on low carbon mining as claimed in claim 1, wherein the arrangement mode of the wall type continuous mining continuous filling working face in the second step specifically comprises 2 types: firstly, aiming at a strong seepage isolation zone, improving the original Wangeviry mining method, mining and filling the original isolation coal pillar (protection block) by adopting a roadway type jump mining method, and then mining the Wangeviry block (mining block); and the mining parameters satisfy the formula (2); secondly, aiming at the medium and weak seepage isolation zones, the original WangGeviry coal mining method is improved, isolation coal pillars are not left between the WangGeviry mining block sections at all, the jumping mining filling is carried out on the mining block sections,
Nd2＜2lsinα+d1 (2)
wherein N is the number of the protection block section supporting lanes, N is more than or equal to 1, and N is an integer; d2The width of a branch roadway of the protective block section; l is the length of the mining block section underground mining; d1The length of a branch roadway of the mining block section; alpha is an included angle between a mining block branch roadway and a mining cave.
6. The overburden seepage isolation zone stability control method based on low carbon mining as claimed in claim 1, wherein in step three: the critical strength of the filling body for maintaining the bearing stability is obtained according to the stress characteristics of the filling body, the strength of the filling material needs to satisfy the formula (3),
wherein, PmaxIs the maximum load of the filling body, MPa; h is the coal seam buried depth m; lambda is a safety factor; sigmacThe uniaxial compressive strength of the filling body measured in a laboratory is MPa; m is the coal seam mining height M; w is the width of the filling body in the wall type continuous mining and continuous filling, m.
7. The overburden seepage isolation zone stability control method based on low carbon mining as claimed in claim 1, wherein in step four: judging whether the seepage isolation zone is broken or not by adopting a formula (4),
in the formula (I), the compound is shown in the specification,
maximum tensile stress of the rock stratum of the seepage isolation zone; hsIn order to isolate the thickness of the formation in the zone for seepage,
the maximum bending moment of the rock stratum of the seepage isolation zone is set;
allowable tensile stress for the rock stratum of the seepage isolation zone;
aiming at the broken strong seepage isolation zone, adjusting the wall type continuous mining and continuous filling mining parameters: increasing number of lanes N of protection block and reducing width d of lanes of protection block2(ii) a ② the length l of the Wangeviry mining block mining cave and the width d of the branch roadway are reduced1(ii) a ③ to Nd2≥2lsinα+d1When in use, a working surface arrangement mode below the medium seepage intensity is adopted;
aiming at the broken seepage isolation zone with medium and weak seepage isolation strength, the filling rate of the filling body is continuously improved until full mining and full filling.
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