A full life cycle evaluation method for water conservation coal mining effect

Abstract

The present invention discloses a full life cycle evaluation method for water-preserving coal mining effect, which is suitable for the full life cycle evaluation of water-preserving coal mining effect. The following steps are followed: A. Divide the full life cycle of water-preserving coal mining into stages; B. Determine the main influencing factors and evaluation indicators of each stage of the full life cycle of water-preserving coal mining; C. Configure the weights of the full life cycle evaluation indicators of water-preserving coal mining effect based on the DEMATEL method; D. Evaluate the full life cycle evaluation indicators of water-preserving coal mining in combination with the actual situation of the coal mine; E. Calculate the comprehensive score of the full life cycle evaluation of the water-preserving coal mining effect of each scheme based on the TOPSIS method, and obtain the optimal coal mining method. This method can study the effects of different water-preserving coal mining methods for special geological conditions, comprehensively evaluate and compare the advantages and disadvantages of different schemes, which is conducive to better carrying out water-preserving coal mining work, protecting the ecological environment, and achieving sustainable development.

Description

Technical Field

[0001] The invention relates to the technical field of water-preserving coal mining, and in particular to a full life cycle evaluation method for water-preserving coal mining effects. Background Art

[0002] With the high-intensity mining of coal resources, the damage to the ecological environment has gradually attracted attention, and green mining technology for coal mines has emerged. Among them, the water-saving mining technology proposed for coal mining in areas with fragile ecological environment and water shortage has changed the traditional concept and alleviated the water resource pollution and ecological environment damage caused by traditional mining to a certain extent. Its connotation is that the water-bearing structure of the aquifer is not destroyed under the influence of mining, or there is a certain degree of damage but it can be restored. This technology has made a significant contribution to alleviating the ecological environment in the mining area. In recent years, the main coal mining methods, such as longwall comprehensive mechanized one-time full-height coal mining method, limited height mining method, layered intermittent mining method, longwall comprehensive mechanized top coal mining method, shortwall comprehensive mechanized coal mining method, strip mining method and filling mining method, are all effective ways to achieve water-preserving mining. However, the applicability of different coal mining methods will inevitably vary with different coal mine conditions. Establishing a set of evaluation methods can quantitatively evaluate the effects of water-preserving coal mining methods. However, the current scope of consideration of relevant evaluation methods only stays in a single stage, and cannot take into account the influencing factors of the entire life cycle. Therefore, it is necessary to construct a full life cycle evaluation method for the effect of water-preserving coal mining. Summary of the invention

[0003] In response to the above technical problems, the present invention proposes a full life cycle evaluation method for the effect of water-conservation coal mining, which is suitable for the full life cycle evaluation of the effect of water-conservation coal mining. This method can study the effects of different water-conservation coal mining methods according to special geological conditions, and comprehensively evaluate and compare the advantages and disadvantages of different schemes, which is conducive to better carrying out water-conservation coal mining work, protecting the ecological environment, and achieving sustainable development.

[0004] In order to achieve the above technical objectives, the present invention is carried out according to the following steps:

[0005] A full life cycle evaluation method for water-saving coal mining effect is applicable to the full life cycle evaluation of water-saving coal mining effect, and is carried out according to the following steps:

[0006] A. Divide the whole life cycle of water-saving coal mining into stages;

[0007] B. Determine the influencing factors at each stage of the whole life cycle of water-saving coal mining and use them as the evaluation indicators of the whole life cycle of water-saving coal mining effect;

[0008] C. Configure the weights of the full life cycle evaluation indicators of water conservation coal mining effect based on the DEMATEL method;

[0009] D. Evaluate the indicators of the whole life cycle of water conservation coal mining;

[0010] E. Calculate the comprehensive life cycle evaluation scores of each scheme for water-saving coal mining based on the TOPSIS method to obtain the optimal coal mining method;

[0011] The stages required to be divided in step A cover the entire life cycle of water-preserving coal mining, and are specifically divided into three stages: before, during and after water-preserving coal mining;

[0012] The full life cycle evaluation index of the water conservation coal mining effect in step B is determined from the above three stages respectively;

[0013] The evaluation indicators of the water-saving coal mining effect in the pre-mining stage include: effective protective layer thickness I1, impermeable layer permeability I2, impermeable layer position I3, impermeable layer expansion I4, impermeable layer water softness I5, aquifer water richness I6, ecological environment fragility I7, water supply I8, effective mining height I9, mining depth I 10 , propulsion speed I 11 、Working surface inclination angle I 12 、Coal pillar stability I 13 、Working surface width I 14 、Project public support rate I 15 , Water resources carrying capacity I 16 ;

[0014] Among them, the thickness of the effective protective layer I1, the position of the aquiclude I3, the expansion of the aquiclude I4, the water softness of the aquiclude I5, the water richness of the aquifer I6, the water supply situation I8, the advancement speed I 11 、Coal pillar stability I 13 、Working surface width I 14 、Project public support rate I 15 , Water resources carrying capacity I 16 It is a very large evaluation index; the permeability of the impermeable layer I2, the fragility of the ecological environment I7, the effective mining height I9, the mining depth I 10 、Working surface inclination angle I 12 It is a very small evaluation indicator;

[0015] The evaluation indicators of the water conservation coal mining effect in the mining stage include: the proportion of environmental protection investment I 17 、Working face recovery rate I 18 , Energy consumption cost per ton of coal I 19 , water-conducting fracture zone development I 20 、Mine water inflow I 21 , Soil moisture content in coal mining crack area I 22 , Solid waste utilization rate I 23 , water resource consumption per ton of coal I 24 、Degree of ground fissure development I 25 、Destroyed land area I26 , Labor productivity I 27 , Mine water utilization rate I 28 ;

[0016] Among them, the working face recovery rate I 18 , Soil moisture content in coal mining crack area I 22 , Solid waste utilization rate I 23 , Labor productivity I 27 , Mine water utilization rate I 28 It is a very large evaluation indicator; the environmental protection investment accounts for I 17 , Energy consumption cost per ton of coal I 19 , water-conducting fracture zone development I 20 、Mine water inflow I 21 , water resource consumption per ton of coal I 24 、Degree of ground fissure development I 25 、Destroyed land area I 26 It is a very small evaluation indicator;

[0017] The indicators for evaluating the water conservation effect of coal mining in the post-mining stage include: the ecological water level drop I 29 , Land reclamation rate I 30 、Sunk area I 31 , Vegetation coverage I 32 、Heavy metal pollution situation I 33 , soil erosion rate I 34 , Cost-to-income ratio I 35 、Old empty water volume I 36 , Land subsidence management rate I 37 、Waterproofness of residual aquiclude I 38 、Aquifer restoration status I 39 , Abandoned shaft space utilization rate I 40 , Utilization rate and water quality of old empty water I 41 , cumulative ground settlement I 42 、Goaf volume I 43 ;

[0018] Among them, the land reclamation rate I 30 , Vegetation coverage I 32 , Cost-to-income ratio I 35 , Land subsidence management rate I 37 、Waterproofness of residual aquiclude I 38 、Aquifer restoration status I 39 , Abandoned shaft space utilization rate I 40 , Utilization rate and water quality of old empty water I 41 It is a very large evaluation indicator; the ecological water level drop I 29 、Sunk area I 31、Heavy metal pollution situation I 33 , soil erosion rate I 34 、Old empty water volume I 36 , cumulative ground settlement I 42 、Goaf volume I 43 It is an extremely small evaluation indicator.

[0019] The weight vector obtained in step C based on the DEMATEL method is W=[w1,w2,w3...w 44 ], and ∑w i =1.

[0020] The indicator evaluation matrix of the water-saving coal mining life cycle evaluation index in step D is X ij .

[0021] The degree indicators in step D are scored on a scale of 1 to 10. The degree indicators refer to indicators that cannot be quantified, including: water softness of the aquifer I5, water richness of the aquifer I6, ecological environmental fragility I7, water supply I8, coal pillar stability I9, etc. 13 , Water resources carrying capacity I 16 、Degree of ground fissure development I 25 、Heavy metal pollution situation I 33 、Waterproofness of residual aquiclude I 38 、Aquifer restoration status I 39 .

[0022] The indicator evaluation matrix X ij The data of the medium and small evaluation indicators need to be positively processed and converted into very large ones.

[0023]

[0024] In the formula, max is the maximum value; x i Evaluation index value; The converted extremely large evaluation index value.

[0025] In step F, based on the index evaluation matrix X ij Construct the normalized matrix Z ij , and calculate the distance D between the evaluation object and the optimal solution i + The distance D from the worst solution i - , thus obtaining the score C of the evaluation object i ,

[0026]

[0027]

[0028]

[0029] In the formula, i is the i-th evaluation object; j is the j-th evaluation index; w j is the weight of the jth evaluation index; D i + is the distance between the evaluation object and the optimal solution; ij is the normalized matrix Z ij Elements in; Z j + is the normalized matrix Z ij The maximum value of the j-th column element in Z j - is the normalized matrix Z ij The minimum value of the elements in the jth column of D i - is the distance between the evaluation object and the worst solution; C i is the score of the evaluation object; m is the number of evaluation indicators.

[0030] Compared with the existing evaluation methods, the full life cycle evaluation method of water-saving coal mining effect of the present invention has the following advantages:

[0031] Beneficial effects:

[0032] First, the present invention divides the entire life cycle of water-preserving coal mining into three stages for consideration, establishes a full life cycle evaluation method for the effect of water-preserving coal mining, and comprehensively selects the influencing factors of the effect of water-preserving coal mining from the three stages before mining, during mining, and after mining, which can construct evaluation indicators in a more comprehensive, scientific, and systematic manner.

[0033] Second, the indicators are weighted based on the DEMATEL method, and the weights are determined according to the importance of their mutual influence, reflecting the internal relationship between the factors.

[0034] Third, the TOPSIS method is finally used for comprehensive evaluation, which can make full use of the information of the original data and is more objective and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic flow chart of the full life cycle evaluation method of water-preserving coal mining effect of the present invention.

[0036] Figure 2 Schematic diagram of the main evaluation indicators for the entire life cycle of water conservation coal mining effects.

[0037] Figure 3 It is a cause-effect diagram between indicators. DETAILED DESCRIPTION

[0038] The main coal seam in a mine in a western ecologically fragile mining area is 4-2 coal, with an average burial depth of 138m, a thickness of 3.0-3.5m, and an average inclination of 5°. The overlying Quaternary Sarawusu Formation aquifer has water supply value and ecological protection significance, and is the target aquifer that needs to be protected in the mine. During the entire development process of the coal seam, it is necessary to ensure the structural stability of the target aquifer to achieve water-saving coal mining throughout the life cycle. According to the actual situation of the mine, the optional water-saving coal mining technologies include height-limited water-saving coal mining technology X1, filling water-saving coal mining technology X2, and narrow strip water-saving coal mining technology X3.

[0039] The implementation effect of the above water-preserving coal mining technology is evaluated in combination with a full life cycle evaluation method of the water-preserving coal mining effect of the present invention and the accompanying drawings to select the optimal solution.

[0040] A. Divide the whole life cycle of water-saving coal mining into three stages: before mining, during mining and after mining;

[0041] B. Conduct on-site investigations and consult experts, and select corresponding indicators according to the different priorities of water conservation in different stages of coal mining as follows:

[0042] The evaluation indicators in the pre-mining stage are: effective protective layer thickness I1, aquiclude permeability I2, aquiclude layer position I3, aquiclude swelling I4, aquiclude water softness I5, aquifer water richness I6, ecological environmental fragility I7, water supply I8, effective mining height I9, mining depth I 10 , propulsion speed I 11 、Working surface inclination angle I 12 、Coal pillar stability I 13 、Working surface width I 14 、Project public support rate I 15 , Water resources carrying capacity I 16 .

[0043] The evaluation indicators in the mining stage are: environmental protection investment ratio I 17 、Working face recovery rate I 18 , Energy consumption cost per ton of coal I 19 , water-conducting fracture zone development I 20 、Mine water inflow I 21 , Soil moisture content in coal mining crack area I 22 , Solid waste utilization rate I 23 , water resource consumption per ton of coal I 24 、Degree of ground fissure development I 25 、Destroyed land area I 26 , Labor productivity I 27 , Mine water utilization rate I 28 .

[0044] The evaluation index of the post-mining stage is: ecological water level decline I29 , Land reclamation rate I 30 、Sunk area I 31 , Vegetation coverage I 32 、Heavy metal pollution situation I 33 , soil erosion rate I 34 , Cost-to-income ratio I 35 、Old empty water volume I 36 , Land subsidence management rate I 37 、Waterproofness of residual aquiclude I 38 、Aquifer restoration status I 39 , Abandoned shaft space utilization rate I 40 , Utilization rate and water quality of old empty water I 41 , cumulative ground settlement I 42 、Goaf volume I 43 .

[0045] C. Configure the weights of the full life cycle evaluation indicators of water conservation coal mining effect based on the DEMATEL method;

[0046] ① Perform weight allocation within the divided stages, analyze the causal relationship between indicators in combination with expert opinions, and evaluate the impact level in the range of 1 to 10 to obtain the initial direct impact matrix M, see Table 1.

[0047] Table 1 Initial direct impact matrix M

[0048]

[0049]

[0050] By using MATLAB to program and solve, we can get the comprehensive influence matrix M” among various factors, see Table 2.

[0051] Table 2 Comprehensive impact matrix M"

[0052]

[0053] The sum of each row in the comprehensive influence matrix is ​​the influence R of the corresponding factor, and the sum of each column is the influence C of the corresponding factor. According to the steps of solving the cause degree and result degree of the DEMATEL method, the cause degree and result degree corresponding to each factor are obtained, and the results are shown in Table 3.

[0054] Table 3 Centrality and causality of each indicator

[0055]

[0056]

[0057] According to the centrality and cause degree calculated in the above table, the cause-result diagram between indicators is obtained with the centrality as the horizontal axis and the cause degree as the vertical axis, as shown in Figure 3 As shown, the cause-effect relationship of each indicator is analyzed based on this.

[0058] Centrality indicates the closeness of the relationship with other indicators, and causality indicates the degree of influence of the indicator on other indicators. Indicators with causality less than 0 are result indicators, which are greatly affected by other evaluation indicators in the evaluation indicator system, while indicators with causality greater than 0 are causal indicators. The key controllable factors in the causal indicators should be focused on in the ecological environment evaluation and improvement of the mining area.

[0059] It is known that the weight vector of each indicator is W = [w1,w2,w3...w 43 ], and ∑w i = 1. The weights of each indicator are obtained according to the centrality, as shown in Table 4.

[0060] Table 4 Weight configuration of each indicator

[0061]

[0062] D. Evaluate the indicators of the whole life cycle of water conservation coal mining;

[0063] Combining the experts' opinions and on-site assessment, the evaluation matrix is ​​shown in Table 5.

[0064] Table 5 Index evaluation matrix

[0065]

[0066]

[0067] E. Based on the TOPSIS method, the comprehensive score of the life cycle evaluation of the water-saving coal mining effect of each scheme is calculated to obtain the optimal coal mining method.

[0068] The evaluation indicators of the pre-mining stage are effective protective layer thickness I1, aquiclude layer position I3, aquiclude swelling I4, aquiclude water softness I5, aquifer water richness I6, water supply I8, advancement speed I 11 、Coal pillar stability I 13 、Working surface width I 14 、Project public support rate I 15 , Water resources carrying capacity I 16 It is a very large evaluation index. Aquiclude permeability I2, ecological environment fragility I7, effective mining height I9, mining depth I 10 、Working surface inclination angle I 12 It is an extremely small evaluation indicator.

[0069] The evaluation index of the mining stage is the working face recovery rate I 18 , Soil moisture content in coal mining crack area I 22 , Solid waste utilization rate I 23 , Labor productivity I 27 , Mine water utilization rate I 28 It is a very large evaluation indicator. 17 , Energy consumption cost per ton of coal I 19 , water-conducting fracture zone development I 20 、Mine water inflow I 21 , water resource consumption per ton of coal I 24 、Degree of ground fissure development I 25 、Destroyed land area I 26 It is an extremely small evaluation indicator.

[0070] The evaluation index of the post-mining stage is land reclamation rate I 30 , Vegetation coverage I 32 , Cost-to-income ratio I 35 , Land subsidence management rate I 37 、Waterproofness of residual aquiclude I 38 、Aquifer restoration status I 39 , Abandoned shaft space utilization rate I 40 , Utilization rate and water quality of old empty water I 41 It is a very large evaluation indicator. Ecological water level decline I 29 、Sunk area I 31 、Heavy metal pollution situation I 33 , soil erosion rate I 34 、Old empty water volume I 36 , cumulative ground settlement I 42 、Goaf volume I 43 It is an extremely small evaluation indicator.

[0071] The data of the extremely small evaluation indicators in the indicator evaluation matrix need to be positively processed and converted into extremely large ones.

[0072]

[0073] In the formula, max is the maximum value; x i Evaluation index value; The converted extremely large evaluation index value.

[0074] In step E, the index evaluation matrix X ij Construct the normalized matrix Z ij . And calculate the distance D between the evaluation object and the optimal solution i + The distance D from the worst solution i -, thus obtaining the score C of the evaluation object i .

[0075]

[0076]

[0077]

[0078] In the formula, i is the i-th evaluation object; j is the j-th evaluation index; w j is the weight of the jth evaluation index; D i + is the distance between the evaluation object and the optimal solution; ij is the normalized matrix Z ij Elements in; Z j + is the normalized matrix Z ij The maximum value of the j-th column element in Z j - is the normalized matrix Z ij The minimum value of the elements in the jth column of D i - is the distance between the evaluation object and the worst solution; C i is the score of the evaluation object; m is the number of evaluation indicators.

[0079] The results obtained by solving in MATLAB are shown in Table 6.

[0080] Table 6 TOPSIS solution results

[0081]

[0082] In summary, after the full life cycle evaluation of the water-preserving coal mining effect, it can be seen that, combined with the actual conditions of the mine and expert opinions, option X2 ranked 1 should be selected, that is, the implementation of filling water-preserving coal mining technology in this mine can achieve better water-preserving coal mining effects.

Claims

1. A full life cycle evaluation method for water conservation coal mining effect is applicable to the full life cycle evaluation of water conservation coal mining effect, and is carried out according to the following steps: A. Divide the whole life cycle of water-saving coal mining into stages; B. Determine the influencing factors at each stage of the whole life cycle of water-saving coal mining and use them as the evaluation indicators of the whole life cycle of water-saving coal mining effect; C. Configure the weights of the full life cycle evaluation indicators of water conservation coal mining effect based on the DEMATEL method; D. Evaluate the indicators of the whole life cycle of water conservation coal mining; E. Calculate the comprehensive life cycle evaluation scores of each scheme for water-saving coal mining based on the TOPSIS method to obtain the optimal coal mining method; The stages required to be divided in step A cover the entire life cycle of water-preserving coal mining, and are specifically divided into three stages: before, during and after water-preserving coal mining; The full life cycle evaluation index of the water conservation coal mining effect in step B is determined from the above three stages respectively; The evaluation indicators of the water-saving coal mining effect in the pre-mining stage include: effective protective layer thickness I1, impermeable layer permeability I2, impermeable layer position I3, impermeable layer expansion I4, impermeable layer water softness I5, aquifer water richness I6, ecological environment fragility I7, water supply I8, effective mining height I9, mining depth I 10 , propulsion speed I 11 、Working surface inclination angle I 12 、Coal pillar stability I 13 、Working surface width I 14 、Project public support rate I 15 , Water resources carrying capacity I 16 ; Among them, the thickness of the effective protective layer I1, the position of the aquiclude I3, the expansion of the aquiclude I4, the water softness of the aquiclude I5, the water richness of the aquifer I6, the water supply situation I8, the advancement speed I 11 、Coal pillar stability I 13 、Working surface width I 14 、Project public support rate I 15 , Water resources carrying capacity I 16 It is a very large evaluation index; the permeability of the impermeable layer I2, the fragility of the ecological environment I7, the effective mining height I9, the mining depth I 10 、Working surface inclination angle I 12 It is a very small evaluation indicator; The evaluation indicators of the water conservation coal mining effect in the mining stage include: the proportion of environmental protection investment I 17 、Working face recovery rate I 18 , Energy consumption cost per ton of coal I 19 , water-conducting fracture zone development I 20 、Mine water inflow I 21 , Soil moisture content in coal mining crack area I 22 , Solid waste utilization rate I 23 , water resource consumption per ton of coal I 24 、Degree of ground fissure development I 25 、Destroyed land area I 26 , Labor productivity I 27 , Mine water utilization rate I 28 ; Among them, the working face recovery rate I 18 , Soil moisture content in coal mining crack area I 22 , Solid waste utilization rate I 23 , Labor productivity I 27 , Mine water utilization rate I 28 It is a very large evaluation indicator; the environmental protection investment accounts for I 17 , Energy consumption cost per ton of coal I 19 , water-conducting fracture zone development I 20 、Mine water inflow I 21 , water resource consumption per ton of coal I 24 、Degree of ground fissure development I 25 、Destroyed land area I 26 It is a very small evaluation indicator; The indicators for evaluating the water conservation effect of coal mining in the post-mining stage include: the ecological water level drop I 29 , Land reclamation rate I 30 、Sunk area I 31 , Vegetation coverage I 32 、Heavy metal pollution situation I 33 , Soil erosion rate I 34 , Cost-to-income ratio I 35 、Old empty water volume I 36 , Land subsidence management rate I 37 、Waterproofness of residual aquiclude I 38 、Aquifer restoration status I 39 , Abandoned shaft space utilization rate I 40 , old empty water utilization rate and water quality I 41 , cumulative ground settlement I 42 、Goaf volume I 43 ; Among them, the land reclamation rate I 30 , Vegetation coverage I 32 , Cost-Expense-Revenue I 35 , Land subsidence management rate I 37 、Waterproofness of residual aquiclude I 38 、Aquifer restoration status I 39 , Abandoned shaft space utilization rate I 40 , Utilization rate and water quality of old empty water I 41 It is a very large evaluation indicator; the ecological water level drop I 29 、Sunk area I 31 、Heavy metal pollution situation I 33 , Soil erosion rate I 34 、Old empty water volume I 36 , cumulative ground settlement I 42 、Goaf volume I 43 It is an extremely small evaluation indicator.

2. A full life cycle evaluation method for water-saving coal mining effect according to claim 1, characterized in that: The weight vector obtained in step C based on the DEMATEL method is W=[w1,w2,w3...w 44 ], and ∑w i =1.

3. The full life cycle evaluation method for water-saving coal mining effect according to claim 1 is characterized in that: The indicator evaluation matrix of the water-saving coal mining life cycle evaluation index in step D is X ij .

4. The method for evaluating the effect of water-saving coal mining in the whole life cycle according to claim 3 is characterized in that: The degree indicators in step D are scored on a scale of 1 to 10. The degree indicators refer to indicators that cannot be quantified, including: water softness of the aquifer I5, water richness of the aquifer I6, ecological environmental fragility I7, water supply I8, coal pillar stability I9, etc. 13 , Water resources carrying capacity I 16 、Degree of ground fissure development I 25 、Heavy metal pollution situation I 33 、Waterproofness of residual aquiclude I 38 、Aquifer restoration status I 39 .

5. The method for evaluating the effect of water-saving coal mining in the whole life cycle according to claim 4 is characterized in that: The index evaluation matrix X ij The data of the medium and small evaluation indicators need to be positively processed and converted into very large ones. In the formula, max is the maximum value; x i Evaluation index value; The converted extremely large evaluation index value.

6. A full life cycle evaluation method for water-saving coal mining effect according to claim 3, characterized in that: In step E, based on the index evaluation matrix X ij Construct the normalized matrix Z ij , and calculate the distance D between the evaluation object and the optimal solution i + The distance to the worst solution Thus, the score C of the evaluation object is obtained i , In the formula, i is the i-th evaluation object; j is the j-th evaluation index; w j is the weight of the jth evaluation index; D i + is the distance between the evaluation object and the optimal solution; ij is the normalized matrix Z ij Elements in; Z j + is the normalized matrix Z ij The maximum value of the j-th column element in Z j - is the normalized matrix Z ij The minimum value of the elements in the jth column; is the distance between the evaluation object and the worst solution; C i is the score of the evaluation object; m is the number of evaluation indicators.

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