CN114687736B - Method for calculating height of water flowing fractured zone in coal seam group mining - Google Patents
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Abstract
The invention discloses a method for calculating the height of a water flowing fractured zone produced by a coal seam group, which comprises the following steps: determining basic geological mining parameters of a mining area; judging the comprehensive lithology of the overlying rock stratum of the first layer of coal, and calculating the height of a water flowing fractured zone of the first layer of coal mining; judging the comprehensive lithology of the coal interbedded rock stratum, and sequentially calculating according to the depth and the depth to determine the height of the ith coal mining caving zone and the height of the ith coal water diversion fracture zone; respectively comparing the height of the mining caving zone of the ith coal layer, the height of the water flowing fractured zone of the ith coal layer and the size of the coal seam space between the ith-1 coal layer and the ith coal layer, and sequentially determining the overlapping relation between the mining caving zone of the adjacent coal layers and the water flowing fractured zone in the coal seam group according to depth and depth; calculating and determining the comprehensive equivalent mining thickness of the coal seams with different overlapping relations and the comprehensive mining thickness of the coal seam group; and calculating the height of the water flowing fractured zone of the coal seam group mining. The invention provides a new and more comprehensive calculation method for calculating the height of the water flowing fractured zone in the mining area coal seam group condition water-retaining green mining.
Description
Technical Field
The invention relates to the technical field of coal seam mining. In particular to a method for calculating the height of a water flowing fractured zone produced by a coal seam group.
Background
At present, the center of gravity of coal mining gradually shifts in China, and western mining areas are located in arid and semiarid grassland areas, so that the ecological environment is fragile. And the coal seam in the mining area has the characteristics of shallow depth and large mining height, and a water-guiding fracture zone caused after coal resources are mined easily influences the regional water system environment, so that underground water is lost, and the surface ecology is damaged. Most production mines have the characteristic of multilayer coal seams, generally relate to a plurality of coal seams that can be mined, and belong to the mining under the condition of close-range coal seam groups. Therefore, the calculation research on the height of the overburden water flowing fractured zone under the coal seam group mining condition is significant for guiding scientific implementation of water-retaining mining and ecological environment protection of the mine.
At present, a plurality of methods for calculating the height of a coal seam mining water flowing fractured zone mainly comprise the following steps: empirical formula calculation methods, numerical simulation, physical simulation and calculation methods based on key layer theory. The numerical simulation and physical simulation method has the advantages that errors of calculation results caused by differences of models and actual conditions cannot be ignored, and the calculation method based on key layer and other beam-slab mechanics theories solves the problem of part of model errors, but mechanical parameters are too many and are not easy to obtain, and application and popularization of formulas are limited, so that the height leading calculation method commonly applied in China at present is still the calculation method of the empirical formula given in the building, water body, railway and main shaft and roadway coal pillar reservation and coal pressing mining specifications. However, most of the existing methods only consider the mining conditions of single-layer coal, and relatively few research on mining of coal seam groups is carried out. Obviously, the method for calculating the single coal seam water flowing fracture is no longer suitable for the actual needs of coal seam group water retention mining and green mining.
The patent with the application number of 201610679487.X discloses a method for calculating the heights of two zones of a short-distance coal bed group (group), which aims at coal mining under a water body, and defines and classifies the coal bed group (group) according to the quantitative relationship among the coal bed interval, the coal mining thickness of the next group and the height of a caving zone; and a new comprehensive mining thickness calculation formula of the height of two zones of multi-layer coal mining is provided by considering the mining space-time factor. However, in the calculation of the heights of the two zones in the multi-coal seam mining, although the difference between the coal seam spacing and the mining time is considered, the empirical formula in the regulations is still used for the calculation of the comprehensive mining thickness of the target coal seam and the important factor of the lithology is not taken into consideration.
The patent with the application number of 202010410276.2 discloses a method for determining a short-distance thick coal seam mining comprehensive caving ratio and a fracturing ratio, which is characterized in that lithological strength of rock strata between coal seam groups and overlying rock strata of the coal seam groups is divided, calculation results of empirical formulas of mining overburden failure heights of different lithological properties are adopted to be compared with coal seam intervals, the short-distance thick coal seam mining comprehensive caving ratio is determined, and the caving zone height and the comprehensive water diversion fracture zone height are calculated. However, in the calculation of the height of the water flowing fractured zone influenced by multiple coal seam formations, the lithology division is considered, but the calculation problem of the height of the water flowing fractured zone is not considered from the transfer relation between the lithology and the rock stratum mining space among the coal seams by depending on an empirical formula too much.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to provide a method for calculating the height of a water flowing fractured zone mined by a coal seam group, so as to solve the problem that the comprehensive lithology of the coal seam and the mining space transfer relationship among the coal seams are not considered when the water flowing fractured zone mined by the coal seam group is calculated at present.
In order to solve the technical problems, the invention provides the following technical scheme:
a method for calculating the height of a water flowing fractured zone produced by a coal seam group comprises the following steps:
step (1): determining basic geological mining parameters of a mining area;
step (2): judging the comprehensive lithology of the first coal overburden according to the firmness coefficient of the first coal overburden, and calculating to obtain the height of a first coal mining water flowing fractured zone;
and (3): judging the comprehensive lithology of the rock stratum between the coal beds according to the firmness coefficient of the rock stratum between the coal beds, and sequentially calculating according to the depth and the depth to determine the height of the mining caving zone of the ith layer of coal and the height of the water diversion fracture zone of the ith layer of coal; i is the number of shallow and deep coal seam layers, and i is more than or equal to 2;
and (4): respectively comparing the height of a mining caving zone of the ith layer of coal, the height of a water diversion fractured zone of the ith layer of coal and the size of the interval between the coal beds of the ith-1 layer of coal and the ith layer of coal, and sequentially determining the overlapping relation between the mining caving zone and the water diversion fractured zone of the adjacent coal beds in the coal bed group according to depth and shallowness;
and (5): calculating and determining the comprehensive equivalent mining thickness and the comprehensive mining thickness of the coal seam group with different overlapping relations based on the propagation and dispersion principle of rock mass between coal seams of the mining space;
and (6): and calculating the height of the water flowing fractured zone mined by the coal seam group based on the comprehensive mining thickness of the coal seam group.
The method for calculating the height of the water flowing fractured zone of the coal seam group mining comprises the following steps(1) In, the basic geological mining parameters of the mining area include the mining depth H 0 Coal seam mining thickness Mi of ith layer and broken expansion coefficient k of collapsed rock mass pc Fractured rock mass coefficient of crushing and expansion k pf The coal seam distance h between the i-1 th coal layer and the i-th coal layer i-1～i Firmness coefficient f of overlying strata of first-layer coal 1 And the firmness coefficient f of the interbedded rock formation of the i-1 st coal and the i-th coal i-1～i 。
In the method for calculating the height of the water flowing fractured zone in the coal seam group mining, in the step (2), the judgment standard of the comprehensive lithology of the overlying strata of the first coal layer is as follows: when f is 1 When the total lithology of the first coal overburden rock is more than 8, judging the first coal overburden rock as a hard rock; when 3 < f 1 When the total lithology of the first coal overburden rock is less than or equal to 8, judging the comprehensive lithology of the first coal overburden rock as a medium hard rock; when f is 1 And when the lithology is less than or equal to 3, judging the comprehensive lithology of the overlying strata of the first coal layer as a weak rock stratum.
In the method for calculating the height of the water flowing fractured zone mined by the coal seam group, in the step (2), when the comprehensive lithology of the overlying strata of the first layer of coal is judged as a hard strata, the calculation formula of the height of the water flowing fractured zone mined by the first layer of coal is as follows:
when the comprehensive lithology of the overlying strata of the first-layer coal is judged to be the medium-hard strata, the calculation formula of the height of the water-flowing fractured zone produced by the first-layer coal is as follows:
when the comprehensive lithology of the overlying strata of the first layer of coal is judged to be a weak stratum, the calculation formula of the height of the water flowing fractured zone of the first layer of coal mining is as follows:
wherein H li The height of a first-layer coal water-flowing fractured zone is measured in meters (m); m is the first coal mining thickness, and the unit is meter (M); the above calculation formula is suitable for the coal seam occurrence condition with the dip angle of 0-54 degrees. At the moment, if the height H of the first-layer coal water flowing fractured zone is calculated li Not less than the mining depth H 0 The height of the water flowing fractured zone of the coal seam group is the mining depth H when the height of the water flowing fractured zone exceeds the ground surface 0 And ending the calculation; if H is li ＜H 0 Then, the following calculation steps from step (3) to step (5) are continued.
According to the method for calculating the height of the water diversion fractured zone mined by the coal seam group, the judgment standard of the comprehensive lithology of the rock stratum between the coal seams of the i-1 th layer of coal and the i-th layer of coal is as follows: when f is i-1～i When the coal seam pressure is more than 8, judging the comprehensive lithology of the rock stratum between the coal seams of the i-1 th layer of coal and the i-th layer of coal to be a hard rock stratum; when 3 < f i-1～i When the coal seam rock quality is less than or equal to 8, judging the comprehensive lithology of the rock stratum between the coal seams of the i-1 th layer of coal and the i-th layer of coal to be a medium hard rock stratum; when f is i-1～i And when the rock quality is less than or equal to 3, judging the comprehensive lithology of the rock stratum between the coal beds of the i-1 st layer of coal and the i-th layer of coal as a weak rock stratum.
In the method for calculating the height of the coal seam group mining water flowing fractured zone, in the step (3), when the height of the ith coal mining caving zone and the height of the ith coal water flowing fractured zone are calculated: when the comprehensive lithology of the rock stratum between the coal beds of the i-1 th layer of coal and the i-th layer of coal is judged as a hard rock stratum, the calculation formula of the mining caving zone height of the i-th layer of coal is as follows:
the calculation formula of the height of the ith layer of coal water flowing fractured zone is as follows:
when the comprehensive lithology of the rock stratum between the coal beds of the i-1 th layer of coal and the i-th layer of coal is judged to be the medium hard rock stratum, the calculation formula of the mining caving zone height of the i-th layer of coal is as follows:
the calculation formula of the height of the ith layer of coal water flowing fractured zone is as follows:
when the comprehensive lithology of the rock stratum between the coal beds of the i-1 th layer of coal and the i-th layer of coal is judged as a weak rock stratum, the height of the mining caving zone of the i-th layer of coal is calculatedThe formula is as follows:
the calculation formula of the height of the ith layer of coal water flowing fractured zone is as follows:
wherein H ci The height of a caving zone for the ith coal mining is measured in meters (m); h fi The height of the water flowing fractured zone of the ith layer of coal is measured in meters (m); the unit of mining thickness Mi of the ith coal seam is meter (m).
In the method for calculating the height of the water flowing fractured zone mined by the coal seam group, in the step (4), the method for determining the overlapping relation between the mining caving zone and the water flowing fractured zone of the two adjacent coal seams of the i-1 th layer and the i-th layer comprises the following steps: comparing the height H of the i-th coal mining caving zone ci Height H of i-th layer coal water-flowing fractured zone fi And the coal seam spacing h between the i-1 st coal layer and the i-th coal layer i-1～i The magnitude relationship of (1);
when H is present ci ≥h i-1～i Judging that the mining caving zone of the ith coal layer contacts or enters the ith-1 coal layer;
when H is present ci ＜h i-1～i And H fi ≥h i-1～i When the coal mining caving zone of the ith layer is not contacted with the ith-1 layer of coal, but the water diversion caving zone of the ith layer of coal is contacted with or enters the ith-1 layer of coal;
when H is present fi ＜h i-1～i And judging that the water-flowing fractured zone of the ith coal layer does not contact the ith-1 th coal layer.
The method for calculating the height of the mining water guide fractured zone of the coal seam group comprises the step (5) of calculating the comprehensive equivalent mining thickness M 'of the ith layer of coal' i The calculation method comprises the following steps:
when H is present ci ≥h i-1～i That is, when the mining caving zone of the ith coal layer contacts or enters the ith-1 coal layer, the comprehensive equivalent mining thickness of the ith coal layer is M' i The calculation formula of (2) is as follows: m' i ＝M i -(k pc -1)h i-1～i (ii) a In the formula, the comprehensive equivalent mining thickness is M' i In meters (m); k is a radical of pc Between 1.10 and 1.40;
when H is present ci ＜h i-1～i And H fi ≥h i-1～i Namely, when the mining caving zone of the ith layer of coal is not in contact with the ith-1 layer of coal but the water-guiding fissure zone of the ith layer of coal is in contact with or enters the ith-1 layer of coal, the comprehensive equivalent mining thickness of the ith layer of coal is M' i The calculation formula of (c) is: m' i ＝M i -(k pc -1)H ci -(k pf -1)(h i-1～i -H fi ) (ii) a In the formula, the equivalent mining thickness is synthesized to be M' i In meters (m); k is a radical of pc Between 1.10 and 1.40; k is a radical of pf Between 1.01 and 1.05;
when H is present fi ＜h i-1～i That is, when the water-flowing fissure zone of the ith layer of coal does not contact the ith-1 layer of coal, the comprehensive equivalent mining thickness of the ith layer of coal is M' i ＝0。
The method for calculating the height of the mining water flowing fractured zone of the coal seam group comprises the step (5) of calculating the height of the mining water flowing fractured zone of the ith layer according to the comprehensive equivalent mining thickness M 'of the coal seam group' i Sequentially calculating the depth and the depth to obtain the comprehensive equivalent mining thickness M 'of the coal of the i-1 layer' i-1 And the comprehensive equivalent mining thickness of the coal of the i-1 th layer is M' i-1 ＝M i-1 +M' i Finally, M 'is calculated' 1 Namely the comprehensive mining thickness Mz of the coal seam group.
The method for calculating the height of the water flowing fractured zone of the coal seam group mining compares the height H of the water flowing fractured zone of the first layer coal li And depth of cut H 0 The height H of the first-layer coal water flowing fractured zone li Not less than the mining depth H 0 When the height of the water flowing fractured zone exceeds the ground surface, the coal seam group mining water flowing fractured zone height H z Equal to the mining depth H 0 (ii) a Height H of water flowing fractured zone of first coal layer li < depth of cut H 0 Then:
when the comprehensive lithology of the overlying strata of the first coal is judged as the hard strata, the height H of the water flowing fractured zone is exploited by the coal seam group z The calculation formula of (2) is as follows:
when the comprehensive lithology of the overlying strata of the first coal is judged to be the medium hard strata, the height H of the water flowing fractured zone is exploited by the coal seam group z The calculation formula of (c) is:
when the comprehensive lithology of the overlying strata of the first coal layer is judged to be a weak strata, the height H of the water flowing fractured zone is exploited by the coal seam group z The calculation formula of (2) is as follows:
the technical scheme of the invention achieves the following beneficial technical effects:
the invention provides a novel method for calculating the height of a water flowing fractured zone mined by a coal seam group, which considers the influence of comprehensive lithology of rock strata among coal seams, calculates the development height of the water flowing fractured zone mined by the coal seam group according to the principle of propagation and dispersion of mining space in rock masses among the layers and provides a novel and more comprehensive calculation method for calculating the height of the water flowing fractured zone in the condition water-retaining green mining of the coal seam group in a mining area.
The method comprises the steps of calculating the height of a water flowing fractured zone mined by a coal seam group according to a prediction formula of the height of the water flowing fractured zone of a single coal seam by bringing the comprehensive mining thickness of multiple coal seams into the prediction formula, wherein the comprehensive mining thickness is the sum of the first coal thickness and the equivalent mining thickness of each coal seam of the lower layer after the diffusion and consumption of rock masses among the layers; the method for calculating the equivalent mining thickness of each coal seam on the lower layer is divided into three categories (divided according to the overlapping relation of the caving zone and the water-flowing fractured zone between the coal seams), namely the caving zone of the coal seam on the lower layer is in contact with or enters the upper coal seam, the caving zone of the coal seam on the lower layer is not in contact with the upper coal seam, but the fractured zone of the coal seam on the lower layer is in contact with or enters the upper coal seam, and the fractured zone of the coal seam on the lower layer is not in contact with the upper coal seam. The method can realize the prediction of the height of the overlying strata water flowing fractured zone of the coal seam group mining, is more comprehensive compared with the traditional calculation method, and can be better applied to the implementation of the water retention coal mining technology in mining areas and the ecological environment protection.
The method for calculating the height of the water-flowing fractured zone under different overlapping relation conditions is adopted, and compared with a calculation method of a theoretical mechanical formula of the plate girder, the method has the advantages that the parameters are relatively few and are easy to obtain; compared with an empirical formula calculation method, factors such as interlayer lithology and the like are considered, and the accuracy of the calculation result is higher.
Drawings
FIG. 1 is a sectional view showing development characteristics of a first-layer coal mining water-flowing fractured zone in an embodiment of the invention;
FIG. 2 is a schematic view of the situation that the ith coal mining caving zone enters the ith-1 coal in the embodiment of the invention;
FIG. 3 is a schematic diagram illustrating a situation that a coal mining fracture zone of the ith layer has entered a caving zone and is not in contact with coal of the (i-1) th layer in the embodiment of the invention;
FIG. 4 is a schematic diagram of the situation in which the ith coal mining fracture zone does not contact the ith-1 th coal in the example of the invention;
FIG. 5 is a schematic diagram of development characteristics of a water flowing fractured zone produced by a coal seam group in the embodiment of the invention.
Detailed Description
The method for calculating the height of the water flowing fractured zone during mining of the coal seam group is used for calculating the height of the water flowing fractured zone during mining of a certain coal seam group in a mining area of \28390, and the specific calculation steps are as follows:
step (1): determining basic geological mining parameters of a mining area;
the basic geological mining parameters of the mining area determined by the embodiment comprise the mining depth H 0 Actual coal seam mining thickness Mi of each coal seam in the coal seam group and roof rock stratum crushing expansion coefficient (mainly comprising crushing expansion coefficient k of caving rock mass pc And fracture and expansion coefficient k of fractured rock mass pf ) And the coal seam interval h between two adjacent coal seams in the coal seam group i-1～i (coal seam spacing between coal seams of the i-1 st and i-th layers), and firmness coefficient f of overburden of first coal 1 And a firmness coefficient f of an interbedded rock formation between two adjacent coal seams in the coal seam group i-1～i (layer i-1 coal with layer i coal); i is the number of shallow and deep coal seam layers, and i is more than or equal to 2.
Step (2): judging the comprehensive lithology of the first coal overburden according to the firmness coefficient of the first coal overburden, and calculating to obtain the height of a first coal water flowing fracture zone;
the judgment standard of the comprehensive lithology of the overlying strata of the first-layer coal is as follows: when f is 1 When the coal is more than 8, the comprehensive lithology of the overlying strata of the first coal layer is judgedIs a hard rock stratum; when 3 < f 1 When the total lithology of the first coal overburden rock is less than or equal to 8, judging the comprehensive lithology of the first coal overburden rock as a medium hard rock; when f is 1 When the total lithology of the first coal overlying strata is less than or equal to 3, judging the comprehensive lithology of the first coal overlying strata to be a weak rock stratum;
a. when the comprehensive lithology of the overlying strata of the first coal is judged as a hard stratum, the calculation formula of the height of the water flowing fractured zone of the first coal is as follows:
b. when the comprehensive lithology of the overlying rock stratum of the first layer of coal is judged to be the medium-hard rock stratum, the calculation formula of the height of the water flowing fractured zone of the first layer of coal is as follows:
c. when the comprehensive lithology of the overlying strata of the first coal is judged to be a weak stratum, the calculation formula of the height of the water flowing fractured zone of the first coal is as follows:
in the above formula, H li The height of a first-layer coal water-flowing fractured zone is measured in meters (m); m is the first coal mining thickness and the unit is meter (M).
The development characteristics of the first-layer mining water flowing fractured zone are shown in figure 1, and the firmness coefficient f of the overlying strata of the first-layer coal in the embodiment is measured 1 And if the density is not less than 5, judging that the comprehensive lithology of the first coal overburden stratum is a medium-hard stratum. Thus, the height H of the caving zone of the first coal mining c The calculation formula of (2) is as follows:
height H of first-layer coal water-flowing fractured zone li The calculation formula of (2) is as follows:
in this example, M is 3.02M, and therefore,calculating to obtain H c Is 6.9 to 11.3m in terms of H li Is 30.2 to 41.4m. In practical engineering application, in order to ensure mining safety, a maximum value of calculation is generally selected as a final result, so that 41.4m is selected as a predicted height of a first-layer coal water flowing fractured zone in the embodiment, and the calculated height is far smaller than a mining depth H 0 =420m, continue with step 3.
And (3): judging the comprehensive lithology of the rock stratum between the coal beds according to the firmness coefficient of the rock stratum between the coal beds, and sequentially calculating according to the depth and the depth to determine the height of the mining caving zone of the ith layer of coal and the height of the water diversion fracture zone of the ith layer of coal;
the calculation method of the mining caving zone height and the water flowing fractured zone height of each coal seam below the first coal layer is similar to the calculation method of the mining caving zone height of the first coal layer and the water flowing fractured zone height of the first coal layer, and a corresponding mining overburden rock damage height empirical calculation formula is selected according to the coal seam lithology judgment result. Wherein, when the height of the mining caving zone of the ith coal layer and the height of the water flowing fractured zone of the ith coal layer are calculated, the firmness coefficient f is calculated according to the mechanical test numerical value of the lithology between the coal beds of the i-1 th coal layer and the ith coal layer i-1～i And judging whether the comprehensive lithology is a hard rock stratum, a medium hard rock stratum or a soft rock stratum, and sequentially substituting the coal seam mining thickness Mi of each coal seam into a calculation formula from shallow to deep to calculate.
The judgment standard of the comprehensive lithology of the rock stratum between the coal beds of the i-1 th layer of coal and the i-th layer of coal is as follows: when f is i-1～i When the rock formation is more than 8, judging the comprehensive lithology of the rock formation between the coal beds of the i-1 st layer of coal and the i-th layer of coal to be a hard rock formation; when 3 < f i-1～i When the coal seam rock quality is less than or equal to 8, judging the comprehensive lithology of the rock stratum between the coal seams of the i-1 th layer of coal and the i-th layer of coal to be a medium hard rock stratum; when f is i-1～i When the rock property is less than or equal to 3, judging the comprehensive lithology of the rock stratum between the coal beds of the i-1 st layer of coal and the i-th layer of coal as a weak rock stratum;
the specific calculation method of the height of the i-th coal mining caving zone and the height of the i-th coal water flowing fractured zone comprises the following steps:
a. when the comprehensive lithology of the rock stratum between the coal beds of the i-1 th layer of coal and the i-th layer of coal is judged as a hard rock stratum, the calculation formula of the mining caving zone height of the i-th layer of coal is as follows:
the calculation formula of the height of the ith layer of coal water flowing fractured zone is as follows:
b. when the comprehensive lithology of the rock stratum between the coal beds of the i-1 th layer of coal and the i-th layer of coal is judged to be the medium hard rock stratum, the calculation formula of the mining caving zone height of the i-th layer of coal is as follows:
the calculation formula of the height of the coal water flowing fractured zone of the ith layer is as follows:
c. when the comprehensive lithology of the rock stratum between the coal beds of the i-1 th layer of coal and the i-th layer of coal is judged as a weak rock stratum, the calculation formula of the mining caving zone height of the i-th layer of coal is as follows:
the calculation formula of the height of the ith layer of coal water flowing fractured zone is as follows:
wherein H ci The height of a caving zone for the ith coal mining is measured in meters (m); h fi The height of the water flowing fractured zone of the ith layer of coal is measured in meters (m); the unit of mining thickness Mi of the ith coal seam is meter (m).
In this embodiment, the coal seam group is composed of shallow and deep coal seams of 4 layers, the method is adopted to judge the comprehensive lithology of rock strata among the coal seams, and the corresponding calculation formula is adopted to calculate and obtain the height H of the mining caving zone of the ith coal seam ci And the height H of the ith coal water flowing fractured zone fi As shown in table 1.
TABLE 1
And (4): respectively comparing the height of the mining caving zone of the ith coal layer, the height of the water flowing fractured zone of the ith coal layer and the size of the coal seam space between the ith-1 coal layer and the ith coal layer, and sequentially determining the overlapping relation between the mining caving zone of the adjacent coal layers and the water flowing fractured zone in the coal seam group according to depth and depth;
comparing the mining caving zone height H of the ith layer of coal by any two adjacent layers of coal ci Height H of water-flowing fractured zone of coal in i-th layer fi And the coal seam distance h between the coal seam of the i-1 th layer and the coal seam of the i-th layer i-1～i The size relationship can be divided into the following three cases:
a. when H is present ci ≥h i-1～i When the coal is not in the mining caving zone, judging that the mining caving zone of the ith coal layer contacts or enters the ith-1 th coal layer, and referring to figure 2;
b. when H is present ci ＜h i-1～i And H fi ≥h i-1～i If so, judging that the mining caving zone of the ith layer of coal is not in contact with the ith-1 layer of coal, but the water diversion caving zone of the ith layer of coal is in contact with or enters the ith-1 layer of coal, and referring to fig. 3;
c. when H is present fi ＜h i-1～i And judging that the water flowing fractured zone of the ith layer of coal does not contact the ith-1 layer of coal, as shown in figure 4.
Mining caving zone height H according to the ith layer ci Height H of water-flowing fractured zone of coal in i-th layer fi And the coal seam distance h between the coal seam of the i-1 th layer and the coal seam of the i-th layer i-1～i The overlapping relation between the mining caving zone and the water diversion fracture zone of each adjacent coal seam in the coal seam group is determined sequentially according to the depth and the depth, and specific judgment results are shown in table 1.
And (5): calculating and determining comprehensive equivalent mining thickness M 'of coal seams with different overlapping relations based on propagation and dissipation principles of mining space rock mass between coal seams' i And the comprehensive mining thickness Mz of the coal seam group;
the development characteristics of the mining water-flowing fractured zones of adjacent coal seams in the coal seam group are shown in figure 5, and the propagation of the mining space of the lower coal layer at the momentRoughly undergoes: (1) the scattering and consumption effect of the interlaminar rock mass, when the coal reaches the upper coal layer, the mining of the lower coal layer can be regarded as the mining of the upper coal layer with the thickness of M i-1 Is added with an equivalent mining thickness M' i (ii) a (2) The increased mining space continues to spread upwards, and along with the compaction and dissipation of the rock mass in the damage space generated by the primary mining of the coal on the upper layer, the overlying strata damage height continues to grow upwards, and the height of the water-flowing fractured zone is increased.
According to the judgment result of the overlapping relation between the adjacent coal seams in the step (4), the comprehensive equivalent mining thickness of the ith layer of coal can be M' i The calculation method of (a) is divided into the following three cases:
a. when H is present ci ≥h i-1～i Namely when the mining caving zone of the ith coal layer contacts or enters the ith-1 coal layer: in this case, the interbedded rock mass is used as a broken and swollen rock mass to completely fill the gob, and the dissipation effect is mainly the broken and swollen rock mass. Therefore, the comprehensive equivalent mining thickness of the ith layer coal is M' i The calculation formula of (2) is as follows: m' i ＝M i -(k pc -1)h i-1～i (ii) a In the formula, the equivalent mining thickness is synthesized to be M' i In meters (m); k is a radical of formula pc Between 1.10 and 1.40, the numerical value is mainly related to the interlayer lithology, and the harder the interlayer lithology is pc The larger the value;
b. when H is present ci ＜h i-1～i And H fi ≥h i-1～i Namely, when the mining caving zone of the ith coal layer does not contact the ith-1 coal layer, but the water-flowing fractured zone of the ith coal layer contacts or enters the ith-1 coal layer: under the condition, the dissipation effect of the lower coal mining space in the interlaminar rock mass is reflected in the rock mass crushing, swelling and dissipation, and the fracture and separation dissipation of the fractured rock stratum.
The dispersion height of the coal caving zone of the ith layer is as follows: (k) pc -1)H ci ；
The dispersion height of the coal fissure zone of the ith layer is as follows: (k) of pf -1)(h i-1～i -H fi )；
Therefore, the comprehensive equivalent mining thickness of the ith layer coal is M' i The calculation formula of (2) is as follows: m' i ＝M i -(k pc -1)H ci -(k pf -1)(h i-1～i -H fi ) (ii) a In the formula, the comprehensive equivalenceMining thick M' i In meters (m); k is a radical of formula pc Between 1.10 and 1.40; k is a radical of formula pf Between 1.01 and 1.05;
c. when H is present fi ＜h i-1～i Namely when the water flowing fractured zone of the ith layer of coal does not contact the ith-1 layer of coal: at the moment, the mining effect of the lower coal layer on the overlying strata of the upper coal layer is small, and the upward development height of the water-guiding fissure zone is almost unchanged, so that the comprehensive equivalent mining thickness of the ith coal layer is M' i ＝0。
The method for calculating the comprehensive mining thickness Mz of the coal seam group comprises the following steps: according to the comprehensive equivalent mining thickness M 'of the ith layer of coal' i Sequentially calculating the depth and the depth to obtain the comprehensive equivalent mining thickness M 'of the coal of the i-1 layer' i-1 And the comprehensive equivalent mining thickness M 'of the coal of the i-1 st layer' i-1 ＝M i-1 +M' i Finally, calculating to obtain M' 1 Namely the comprehensive mining thickness Mz of the coal seam groups and the comprehensive equivalent mining thickness M 'of each coal seam' i-1 The values are given in Table 1, and the final calculation gives an Mz of 5.74m.
And (6): and calculating the height of the water flowing fractured zone of the coal seam group mining based on the comprehensive mining thickness of the coal seam group.
And substituting the calculated comprehensive mining thickness Mz of the coal seam group into a calculation formula of the height of the first-layer coal water flowing fractured zone, and calculating to obtain the height of the coal seam group mining water flowing fractured zone. In the embodiment, the height H of the water flowing fractured zone produced by the coal seam group z The calculation formula of (2) is as follows:
the height H of the water flowing fractured zone for mining the coal seam group can be determined by calculation z Is 50.5m.
The embodiment provides a novel method for calculating the height of a water flowing fractured zone produced by coal seam groups based on the dispersion and consumption principle of mining space in the propagation of the rock mass between layers. The calculation method has the advantages that: 1) According to the difference of quantitative relations among the coal mining caving zone of the lower layer, the water guide fracture zone and the corresponding coal seam interval, the overlapping relation between the mining caving zone of the adjacent coal seam and the water guide fracture zone is divided into three types, and meanwhile, the propagation and dispersion theory of the mining space in the rock mass is introduced, so that a new thought and method are provided for the calculation of the comprehensive mining thickness of the coal seam group; 2) The present embodiment calculates different overlap relation conditionsCompared with a calculation method of a theoretical mechanical formula of a plate girder, the method for measuring the height of the lower water flowing fractured zone has relatively fewer parameters and is easy to obtain; compared with an empirical formula calculation method, factors such as interlayer lithology and the like are considered. The height H of the water flowing fractured zone for mining the coal seam group is obtained through calculation in the embodiment z The height of the water flowing fractured zone exploited by the coal seam group is 41.5m, which is calculated by an empirical formula, and the height of the water flowing fractured zone exploited by the coal seam group, which is actually measured by drilling holes after actual exploitation, is 47.9m, so that the calculation result of the embodiment has higher precision.
In other embodiments, the judgment of comprehensive lithology of overlying strata and comprehensive lithology among coal seams of the coal seam group can also adopt indexes such as hard rock proportion or comprehensive compressive strength of strata to carry out strength division; the method for calculating the height of the first-layer coal (single coal seam) water-flowing fractured zone refers to the 'three-down' coal mining procedure, and the method can be completely replaced by an empirical formula which is actually measured on site and is practically summarized in a mining area for many years by a person skilled in the art.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications are possible which remain within the scope of the appended claims.
Claims (3)
1. A method for calculating the height of a water flowing fractured zone produced by a coal seam group is characterized by comprising the following steps:
step (1): determining basic geological mining parameters of a mining area;
basic geological mining parameters of a mine include depth of cutH 0 Coal seam mining thickness of ith layerMiBroken expansion coefficient of caving rock massk pc Fractured rock mass coefficient of expansionk pf Coal seam distance between the i-1 th coal and the i-th coalh i-1～i Firmness coefficient of overlying strata of first-bed coalf 1 And the i-1 st coal and the iFirmness coefficient of interbedded rock formation of i-layer coalf i-1～i ；
Step (2): judging the comprehensive lithology of the first coal overlying strata according to the firmness coefficient of the first coal overlying strata, and calculating to obtain the height of the first coal mining water flowing fractured zone;
when the comprehensive lithology of the overlying strata of the first-layer coal is judged to be a hard stratum, the calculation formula of the height of the water-flowing fractured zone of the first-layer coal is as follows:
；
when the comprehensive lithology of the overlying strata of the first-layer coal is judged to be the medium-hard strata, the calculation formula of the height of the water-flowing fractured zone of the first-layer coal is as follows:
；
when the comprehensive lithology of the overlying strata of the first-layer coal is judged to be a weak stratum, the calculation formula of the height of the water-flowing fractured zone of the first-layer coal is as follows:
；
wherein, the first and the second end of the pipe are connected with each other,H li the height of a first-layer coal water-flowing fractured zone is meter and m;Mthe first layer of coal is mined thickly, and the unit is meter and m;
and (3): judging the comprehensive lithology of the rock stratum between the coal beds according to the firmness coefficient of the rock stratum between the coal beds, and sequentially calculating according to the shallow depth and the deep depth to determine the height of the mining caving zone of the ith layer of coal and the height of the water-flowing fractured zone of the ith layer of coal; i is the number of shallow and deep coal seam layers, and i is more than or equal to 2;
and (4): respectively comparing the height of the mining caving zone of the ith coal layer, the height of the water flowing fractured zone of the ith coal layer and the size of the coal seam space between the ith-1 coal layer and the ith coal layer, and sequentially determining the overlapping relation between the mining caving zone of the adjacent coal layers and the water flowing fractured zone in the coal seam group according to depth and depth;
and (5): calculating and determining the comprehensive equivalent mining thickness and the comprehensive mining thickness of the coal seam group with different overlapping relations based on the propagation and dispersion principle of rock mass between coal seams of the mining space;
and (6): calculating the height of a water flowing fractured zone mined by the coal seam group based on the comprehensive mining thickness of the coal seam group;
in the step (3), when the height of the ith coal mining caving zone and the height of the ith coal water flowing fractured zone are calculated: when the comprehensive lithology of the rock stratum between the coal beds of the i-1 th layer of coal and the i-th layer of coal is judged as a hard rock stratum, the calculation formula of the mining caving zone height of the i-th layer of coal is as follows:
the formula for calculating the height of the coal water flowing fractured zone of the ith layer is as follows:
；
when the comprehensive lithology of the rock stratum between the coal beds of the i-1 th layer of coal and the i-th layer of coal is judged to be the medium hard rock stratum, the calculation formula of the mining caving zone height of the i-th layer of coal is as follows:
the formula for calculating the height of the ith coal water flowing fractured zone is as follows:
；
when the comprehensive lithology of the rock stratum between the coal beds of the i-1 th layer of coal and the i-th layer of coal is judged as a weak rock stratum, the calculation formula of the mining caving zone height of the i-th layer of coal is as follows:
the formula for calculating the height of the coal water flowing fractured zone of the ith layer is as follows:
；
wherein the content of the first and second substances,H ci the height of a caving zone for the ith coal mining is meter and m; H fi the height of the water flowing fractured zone of the ith layer of coal is meter and m; coal seam of i-th layerThickness of the pipeMiThe unit of (a) is meter, m;
in the step (4), the method for determining the overlapping relation between the mining caving zone and the water flowing fractured zone of the ith-1 th layer and the mining caving zone of the ith layer comprises the following steps: comparing the height of the caving zone of the ith coal miningH ci 、Height of i-th layer coal water-flowing fractured zoneH fi And the coal seam distance between the i-1 th coal layer and the i-th coal layerh i-1～i The magnitude relationship of (1);
when in useH ci ≥h i-1～i Judging that the mining caving zone of the ith coal layer contacts or enters the ith-1 coal layer;
when the temperature is higher than the set temperatureH ci ＜h i-1～i And is provided withH fi ≥h i-1～i When the coal is mined, judging that the mining caving zone of the ith coal layer is not in contact with the ith-1 coal layer, but the water-conducting fracture zone of the ith coal layer is in contact with or enters the ith-1 coal layer;
when in useH fi ＜h i-1～i Judging that the water flowing fractured zone of the ith layer of coal does not contact the ith-1 layer of coal;
in the step (5), the comprehensive equivalent mining thickness of the ith layer of coal is M' i The calculation method comprises the following steps:
when the temperature is higher than the set temperatureH ci ≥h i-1～i That is, when the mining caving zone of the ith layer coal contacts or enters the ith-1 layer coal, the comprehensive equivalent mining thickness of the ith layer coal is M' i The calculation formula of (c) is: m' i =M i -(k pc -1)h i-1～i (ii) a In the formula, the comprehensive equivalent mining thickness is M' i The unit of (a) is meter, m;k pc between 1.10 and 1.40;
when in useH ci ＜h i-1～i And isH fi ≥h i-1～i That is, when the mining caving zone of the ith coal layer does not contact the ith-1 coal layer but the water-guiding fissure zone of the ith coal layer contacts or enters the ith-1 coal layer, the comprehensive equivalent mining thickness of the ith coal layer is M' i The calculation formula of (2) is as follows: m' i =M i -(k pc -1) H ci -(k pf -1) (h i-1～i -H fi ) (ii) a In the formula, the equivalent mining thickness is synthesized to be M' i The unit of (a) is meter, m;k pc between 1.10 and 1.40;k pf between 1.01 and 1.05;
when the temperature is higher than the set temperatureH fi ＜h i-1～i That is, when the water-flowing fissure zone of the ith layer of coal does not contact the ith-1 layer of coal, the comprehensive equivalent mining thickness of the ith layer of coal is M' i =0；
According to the comprehensive equivalent mining thickness M 'of the coal of the ith layer' i Sequentially calculating the depth and the depth to obtain the comprehensive equivalent mining thickness M 'of the coal of the i-1 layer' i-1 And the comprehensive equivalent mining thickness of the coal of the i-1 th layer is M' i-1 = M i-1 +M' i Finally, M 'is calculated' 1 Namely the comprehensive mining thickness Mz, M of the coal seam group i-1 The thickness of the i-1 st layer of coal is mined;
comparing the height of the first layer coal water flowing fractured zoneH li And depth of cutH 0 The height of the first-layer coal water-flowing fractured zoneH li Not less than the mining depthH 0 When the height of the water flowing fractured zone exceeds the ground surface, the coal seam group is exploited to the height of the water flowing fractured zone
Equal to the depth of miningH 0 (ii) a Height of water-flowing fractured zone of first coal layerH li < depth of cutH 0 And then:
when the comprehensive lithology of the overlying strata of the first-layer coal is judged as a hard stratum, the height of the water flowing fractured zone exploited by the coal seam group
The calculation formula of (2) is as follows:
；
when the comprehensive lithology of the overlying strata of the first coal is judged to be the medium hard strata, the height of the water flowing fractured zone is exploited by the coal seam group
The calculation formula of (c) is:
；
when the comprehensive lithology of the overlying strata of the first coal layer is judged to be a weak stratum, the height of the water flowing fractured zone is exploited by the coal seam group
The calculation formula of (2) is as follows:
。
2. the method for calculating the height of the water flowing fractured zone mined from the coal seam group according to the claim 1, wherein in the step (2), the judgment standard of the comprehensive lithology of the overlying strata of the first coal layer is as follows: when in usef 1 When the total lithology of the first coal overburden rock is more than 8, judging the first coal overburden rock as a hard rock; when 3 <f 1 When the total lithology of the first coal overburden rock is less than or equal to 8, judging the comprehensive lithology of the first coal overburden rock as a medium hard rock; when in usef 1 And when the total lithology of the first coal overburden rock is less than or equal to 3, judging the comprehensive lithology of the first coal overburden rock to be a weak rock.
3. The method for calculating the height of the water flowing fractured zone mined from the coal seam group according to claim 1, wherein the judgment standard of the comprehensive lithology of the rock stratum between the coal seams of the i-1 th layer of coal and the i-th layer of coal is as follows: when in usef i-1～i When the coal seam pressure is more than 8, judging the comprehensive lithology of the rock stratum between the coal seams of the i-1 th layer of coal and the i-th layer of coal to be a hard rock stratum; when 3 <f i-1～i When the rock property is less than or equal to 8, judging the comprehensive lithology of the rock stratum between the coal beds of the i-1 st layer of coal and the i-th layer of coal as a medium hard rock stratum; when in usef i-1～i And when the rock quality is less than or equal to 3, judging the comprehensive lithology of the rock stratum between the coal beds of the i-1 st layer of coal and the i-th layer of coal as a weak rock stratum.
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103513281A (en) * | 2013-10-23 | 2014-01-15 | 中国矿业大学 | Method for estimating development height of overlying strata water flowing fractured zone of solid filling and coal mining |
| CN103778480A (en) * | 2014-01-14 | 2014-05-07 | 辽宁工程技术大学 | Fissure-zone height prediction method based on sensitivity analysis |
| CN105257337A (en) * | 2015-10-20 | 2016-01-20 | 辽宁工程技术大学 | Filling mining overlying rock fault zone height determining method based on plate and shell theory |
| CN107728228A (en) * | 2017-10-20 | 2018-02-23 | 贵州工程应用技术学院 | Coal mining under water bodies overlying strata water flowing fractured zone development height method for predicting |
| CN110489928A (en) * | 2019-09-05 | 2019-11-22 | 山东大学 | Shallow buried coal seam mining area water flowing fractured zone development height method for predicting and system |
| CN110714754A (en) * | 2019-10-15 | 2020-01-21 | 神华神东煤炭集团有限责任公司 | Method, system and storage medium for determining height of fractured zone and height of caving zone |
| CN110765642A (en) * | 2019-11-05 | 2020-02-07 | 中煤能源研究院有限责任公司 | Zonal evaluation method for roof rock stratum structure of coal seam, mining area or working face |
| CN112948924A (en) * | 2021-02-06 | 2021-06-11 | 合肥工业大学 | Near unconsolidated formation mining water flowing fractured zone height determination method based on overlying strata structure |
| CN113010993A (en) * | 2021-01-19 | 2021-06-22 | 鄂尔多斯市华兴能源有限责任公司 | Method for predicting height of water-guiding crack zone in thick-punching laminated mining area |
-
2022
- 2022-04-02 CN CN202210357254.3A patent/CN114687736B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103513281A (en) * | 2013-10-23 | 2014-01-15 | 中国矿业大学 | Method for estimating development height of overlying strata water flowing fractured zone of solid filling and coal mining |
| CN103778480A (en) * | 2014-01-14 | 2014-05-07 | 辽宁工程技术大学 | Fissure-zone height prediction method based on sensitivity analysis |
| CN105257337A (en) * | 2015-10-20 | 2016-01-20 | 辽宁工程技术大学 | Filling mining overlying rock fault zone height determining method based on plate and shell theory |
| CN107728228A (en) * | 2017-10-20 | 2018-02-23 | 贵州工程应用技术学院 | Coal mining under water bodies overlying strata water flowing fractured zone development height method for predicting |
| CN110489928A (en) * | 2019-09-05 | 2019-11-22 | 山东大学 | Shallow buried coal seam mining area water flowing fractured zone development height method for predicting and system |
| CN110714754A (en) * | 2019-10-15 | 2020-01-21 | 神华神东煤炭集团有限责任公司 | Method, system and storage medium for determining height of fractured zone and height of caving zone |
| CN110765642A (en) * | 2019-11-05 | 2020-02-07 | 中煤能源研究院有限责任公司 | Zonal evaluation method for roof rock stratum structure of coal seam, mining area or working face |
| CN113010993A (en) * | 2021-01-19 | 2021-06-22 | 鄂尔多斯市华兴能源有限责任公司 | Method for predicting height of water-guiding crack zone in thick-punching laminated mining area |
| CN112948924A (en) * | 2021-02-06 | 2021-06-11 | 合肥工业大学 | Near unconsolidated formation mining water flowing fractured zone height determination method based on overlying strata structure |
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