Advanced prediction method of dynamic dangerous degree of gas concentration in coal mining face

Abstract

The present invention belongs to the field of prediction of dangerous gas concentration in coal mining working faces in underground coal mines, and specifically is a method for advanced prediction of dynamic dangerousness of gas concentration in coal mining working faces. The method includes the following steps: S100: regularly and continuously recording monitoring data of gas concentration in coal mining working faces and coal falling amount per unit time in the working faces, gas extraction flow, air intake, and working resistance of the middle support in the working faces; S200: constructing and determining the functional relationship between gas concentration in coal mining working faces and coal falling amount per unit time, gas extraction flow, air intake, and working resistance of the support; S300: calculating the instability domain of gas concentration control activities composed of coal falling amount per unit time, gas extraction flow, air intake, and working resistance of the support; S400: calculating the real-time distance between the real-time state of production control activities and the instability domain, and performing dimensionless normalization processing; S500: calculating the dynamic dangerousness of the state of gas concentration control activities in coal mining working faces, which is the advanced prediction value of the dynamic dangerousness of gas concentration.

Description

Technical Field

[0001] The invention belongs to the field of prediction of gas concentration hazard of coal mining working face in underground coal mines, and specifically is an advanced prediction method of dynamic hazard degree of gas concentration of coal mining working face. Background Art

[0002] Gas disaster is one of the five major disasters in coal mines. The dynamic hazard prediction of gas concentration in coal mining faces is an important basis for the prevention and control of gas accidents, and is of great significance for ensuring the safety of coal mine production.

[0003] At present, the commonly used methods for predicting gas concentration hazard are mainly time series prediction method and calculation model prediction method. The time series prediction method is a relatively objective prediction method that gives prediction results based on data by statistically analyzing and processing the historical data of gas concentration in the production process to infer the development trend of gas concentration status. Data processing methods are the main research content of time series prediction method, such as gas hazard prediction based on simple time series average method, gas hazard prediction based on weighted time series average method, gas hazard prediction based on exponential moving average method, gas hazard prediction based on linear / nonlinear method, etc. The calculation model prediction method calculates the future state of gas concentration by establishing a mathematical model for predicting gas concentration. Commonly used calculation models include: regression analysis, grey prediction method, Markov prediction method, etc. For example, there have been studies on the Gaussian process regression prediction model of working face gas concentration, the least squares support vector machine weighted prediction model of gas concentration, the gas concentration hazard prediction model based on regression analysis, the multivariate distributed lag prediction model of gas concentration, and the dynamic gas hazard prediction based on the combination of unbiased grey GM (1, 1) model and Markov model.

[0004] The above-mentioned gas concentration hazard prediction method has certain guiding significance for the safe management and control of gas in coal mining working faces. However, the existing hazard prediction methods all infer the development trend of gas concentration based on the state change data of gas concentration, without considering the internal driving force of gas concentration change - the effect of "production activities" on the change of gas concentration state. In fact, in the evolution process of gas concentration from safety to danger and then to over-limit, it is the change of production activities (such as a significant change in coal mining volume, a change in gas extraction flow, a change in air volume, etc.) that leads to the change of gas concentration, which in turn causes the occurrence of gas over-limit accidents. The change of activity state is the internal cause of the accident, the internal driving force of the accident evolution, and the causal antecedent of gas concentration change. Therefore, the dynamic hazard measurement of the production activity state that affects the change of gas concentration can realize the advance prediction of the dynamic hazard of gas concentration. Summary of the invention

[0005] The production control activity factors that affect the gas concentration in the coal mining face include the amount of coal falling per unit time on the face, the gas extraction flow rate, the air intake, and the degree of collapse of the goaf due to pressure from the face (which can be quantified by the working resistance of the support). In order to achieve a fundamental prediction of the dangerousness of the gas concentration in the coal mining face, the present invention measures the dynamic dangerousness of the production activity state that affects the change in gas concentration, and provides an advanced prediction method for the dynamic dangerousness of the gas concentration in the coal mining face.

[0006] The present invention adopts the following technical scheme: an advance prediction method for the dynamic danger degree of gas concentration in a coal mining face, comprising the following steps, S100: regularly and continuously recording the monitoring data of the gas concentration in the coal mining face and the amount of coal falling per unit time in the face, gas extraction flow, air intake and support working resistance; S200: using the monitoring data in S100, constructing a functional relationship between the gas concentration in the coal mining face and the amount of coal falling per unit time, gas extraction flow, air intake and support working resistance; S300: according to the functional relationship constructed in S200, calculating the instability domain of the gas concentration control activity composed of the amount of coal falling per unit time, gas extraction flow, air intake and support working resistance; S400: calculating the real-time distance between the real-time state of the production control activity and the instability domain, and performing dimensionless normalization processing; S500: using the dimensionless normalized real-time distance, calculating the dynamic danger degree of the control activity state of the gas concentration in the coal mining face, that is, the advance prediction value of the dynamic danger degree of the gas concentration.

[0007] In step S100, the data is recorded every 30 minutes, and the data is continuously monitored and counted for 10 days.

[0008] The specific calculation process of step S200 is:

[0009] S201: x is the gas concentration at the coal mining face, z 1 is the coal falling amount per unit time at the coal mining face, z 2 is the gas extraction flow rate, z 3 is the air volume into the working surface, z 4 is the working resistance of the middle support of the working face, then the functional relationship model between gas concentration and coal falling amount per unit time, gas extraction flow, air intake, and support working resistance is shown in Formula 1;

[0010] (1)

[0011] In the formula, , is the coefficient to be determined, i = 0, 1, 2, 3, 4; j = 1, 2, 3, 4.

[0012] S202: Substitute the monitoring data into Formula 1, establish a regression equation group, and determine the unknown coefficients in the formula by solving the equation group , , a clear functional relationship is obtained with gas concentration as the dependent variable and coal falling amount per unit time, gas extraction flow, air intake, and support working resistance as independent variables. G .

[0013] The specific calculation process of step S300 is:

[0014] S301: According to the gas concentration warning value set at the coal mining face q and the gas concentration range of gas explosion, determine the instability region of gas concentration A ,Right now x ∈ A ;

[0015] S302: All the factors that make the gas concentration in the coal mining face fall into its instability zone A The state combination of coal falling amount per unit time, gas extraction flow, air intake, and support working resistance is the instability domain of gas concentration control activity. B , and its calculation process is shown in Formula 2.

[0016] (2).

[0017] In the formula, a j is the instability region of gas concentration A The point in j = 1, 2, …, n .

[0018] The specific calculation process of step S400 is:

[0019] S401: Set z 1( t ), z 2( t ), z 3( t ), z 4( t ) are respectively t The coal falling volume per unit time, gas extraction flow, air intake and working resistance of the intermediate support at the coal mining face at all times, the real-time status of production control activities and their instability domain B The calculation formula of the real-time distance between is shown in Formula 3:

[0020] (3).

[0021] In the formula, b i The unstable domain of production control activity stateB The point in i = 1, 2, …, m .

[0022] S402: Set is the real-time distance between the real-time state of production control activities and the instability domain after dimensionless normalization. Its specific calculation formula is shown in Formula 4.

[0023] (4)

[0024] In the formula, r It is the data group number collected during the long-term production process.

[0025] The specific calculation process of step S500 is:

[0026] Real-time distance using dimensionless normalization , calculate the dynamic hazard of the gas concentration control activity state of the coal mining face, which is the advance prediction value of the dynamic hazard of gas concentration , the specific calculation process is shown in formula 5,

[0027] (5)

[0028] In the formula, for t The dimensionless normalized real-time distance at the moment after the moment; , is an undetermined coefficient, which is determined according to the change range of the gas concentration production control activity state in the coal mining face. , The value of satisfies ∈[0, 1].

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] At present, the prediction of gas concentration is based on the state change data of gas concentration in the system to infer its development trend. The internal driving force of gas concentration change - the effect of "production activities" on the change of gas concentration state is not considered. It is impossible to predict the danger of gas concentration in essence, and the prediction results are superficial.

[0031] The present invention proposes to measure the danger of the production activity status that affects the change in gas concentration, which is an in-depth advance prediction of the danger of gas concentration. The prediction result is more advanced and can lay a solid foundation for the real pre-control of gas accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1The present invention is a flow chart of the method for advanced prediction of the dynamic danger level of gas concentration in a coal mining face. DETAILED DESCRIPTION

[0033] The present invention is further explained in detail below in conjunction with the drawings in the specification so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0034] See also Figure 1 As shown in the figure, an advance prediction method for the dynamic hazard degree of gas concentration in coal mining working face is firstly used to monitor and record the monitoring data of gas concentration in coal mining working face and the amount of coal falling per unit time, gas extraction flow, air intake, and working resistance of the middle support of the working face every 30 minutes for 10 consecutive days. Then, the monitoring data is used to construct a functional relationship between gas concentration in coal mining working face and the amount of coal falling per unit time, gas extraction flow, air intake, and working resistance of the support. The functional relationship is used to calculate the instability domain of gas concentration control activities composed of the amount of coal falling per unit time, gas extraction flow, air intake, and working resistance of the support. On this basis, the real-time distance between the real-time state of production control activities and the instability domain is calculated, and dimensionless normalization is performed. Finally, the dynamic hazard degree of the state of gas concentration control activities in coal mining working face is calculated, which is the advance prediction value of the dynamic hazard degree of gas concentration.

[0035] The specific process is:

[0036] S100: Record the monitoring data of gas concentration in the coal mining face, coal falling volume per unit time, gas extraction flow, air intake, and working resistance of the middle support of the working face every 30 minutes, and monitor and compile data continuously for 10 days.

[0037] S200: Using continuous monitoring data and adopting the multivariate regression method, a functional relationship is constructed to determine the gas concentration in the coal mining face and the amount of coal falling per unit time, gas extraction flow, air intake, and support working resistance.

[0038] See also Figure 1 As shown, the specific calculation method of the functional relationship in this embodiment is:

[0039] set up x is the gas concentration at the coal mining face, z 1 is the coal falling amount per unit time at the coal mining face, z 2 is the gas extraction flow rate, z 3 is the air volume into the working surface, z 4 is the working resistance of the middle support of the working face, and the functional relationship model between gas concentration and coal falling amount per unit time, gas extraction flow rate, air intake, and support working resistance is shown in Formula 1.

[0040] (1)

[0041] In the formula, , is the coefficient to be determined, i = 0, 1, 2, 3, 4; j = 1, 2, 3, 4.

[0042] Substitute the continuous monitoring data into formula 1, establish a regression equation group, and determine the unknown coefficients in the formula by solving the equation group. , , a clear functional relationship is obtained with gas concentration as the dependent variable and coal falling amount per unit time, gas extraction flow, air intake, and support working resistance as independent variables. G .

[0043] Taking the monitoring data of gas concentration, coal falling volume per unit time, gas extraction flow rate, air intake volume, and working resistance of the intermediate support at the coal mining face "P" of a certain underground coal mine as an example, the functional relationship between the gas concentration and its production control activity state is obtained by solving the regression equation group as shown below.

[0044]

[0045] S300: According to the functional relationship G , calculate the instability domain of gas concentration control activity composed of coal falling amount per unit time, gas extraction flow rate, air intake volume, and support working resistance.

[0046] See also Figure 1 As shown, the specific calculation method of the instability region of the gas concentration control activity in this embodiment is:

[0047] According to the gas concentration warning value set at the coal mining face q =0.8%, gas concentration range of gas explosion [5%, 16%], determine the instability range of gas concentration A =[0.8%, 16%], that is x ∈[0.8%, 16%];

[0048] All the gas concentration in the coal mining face falls into its instability zone A The state combination of coal falling amount per unit time, gas extraction flow, air intake, and support working resistance is the instability domain of gas concentration control activity. B , and its calculation process is shown in Formula 2.

[0049] (2).

[0050] In the formula, a j is the instability region of gas concentration A The point inj = 1, 2, …, n .

[0051] Taking the coal mining face "P" as an example, the calculation example of the instability zone of gas concentration control activity is given as follows:

[0052] According to the determined gas concentration instability range A =[0.8%, 16%], and the functional relationship between the gas concentration determined in S200 and its production control activity state, the instability domain of the gas concentration control activity of the coal mining working face "P" is obtained B As shown below.

[0053]

[0054] S400: Calculate the real-time distance between the real-time state of the production control activity and the instability domain, and perform dimensionless normalization processing.

[0055] See also Figure 1 As shown, the specific calculation method of the real-time distance between the real-time state of the control activity and the instability domain and the dimensionless normalization processing in this embodiment is:

[0056] set up z 1( t ), z 2( t ), z 3( t ), z 4( t ) are respectively t The calculation formula for the real-time distance between the real-time state of production control activities and the instability domain, including the coal falling amount per unit time, gas extraction flow, air intake and working resistance of the intermediate support at the coal mining face at each moment, is shown in Equation 3.

[0057] (3)

[0058] In the formula, b i The unstable domain of production control activity state B The point in i = 1, 2, …, m .

[0059] Taking the coal mining face "P" of an underground coal mine as an example, the calculation example of the real-time distance between the real-time state of production control activities and the instability domain is given as follows:

[0060] Assume that the working surface is t Coal falling per unit time z 1( t ) =2025 t / h, gas extraction flow z2( t ) =1091 m³ / min, air intake z 3( t ) =2520 m³ / min and the working resistance of the intermediate support z 4( t ) =30.1 MPa. After calculation, the coal mining face "P" is t The real-time distance between the real-time status of production control activities and the instability domain at each moment is shown below.

[0061]

[0062] set up It is the real-time distance between the real-time state of production control activities and the instability domain after dimensionless normalization. Its specific calculation formula is shown in Formula 4.

[0063] (4)

[0064] In the formula, r It is the data group number collected during the long-term production process.

[0065] Taking the coal mining face "P" of an underground coal mine as an example, the calculation example of dimensionless normalization of the real-time distance between the real-time state of production control activities and the instability domain is given as follows:

[0066] exist t The real-time distance between the real-time state of production control activities and the instability domain is d (z( t ), B )=54.03, the production practice of the working face shows that the minimum distance is min{ d (z( t ), B )}=13.2, the maximum distance is max{ d (z( t ), B )}=142.5, therefore, the real-time distance between the real-time state of production control activities and the instability domain after dimensionless normalization is as follows:

[0067]

[0068] S500: Utilizing the dimensionless normalized real-time distance, the dynamic danger degree of the gas concentration control activity state of the coal mining working face is calculated, which is the advanced prediction value of the dynamic danger degree of the gas concentration.

[0069] See also Figure 1 As shown, the specific calculation method of the advanced prediction value of the dynamic danger degree of gas concentration in this embodiment is shown in Formula 5.

[0070] (5)

[0071] In the formula, for t The dimensionless normalized real-time distance at the moment after the moment; , is an undetermined coefficient, which can be determined according to the change range of the gas concentration production control activity state in the coal mining face. , The value of satisfies ∈[0, 1].

[0072] Taking the coal mining face "P" in an underground coal mine as an example, a specific calculation example of the advanced prediction value of the dynamic danger degree of gas concentration is given as follows:

[0073] Assume that the working surface is at ( t +1) The amount of coal falling per unit time z 1( t +1) =2500 t / h, gas extraction flow z 2( t +1) =1091 m³ / min, air intake z 3( t +1) =2520 m³ / min and working resistance of the intermediate support z 4( t +1) =55MPa, after calculation, the coal mining face "P" is ( t +1) The real-time distance between the real-time status of production control activities and the instability domain at the moment is shown as follows.

[0074]

[0075] Coal mining face "P" at ( t +1) The dimensionless normalized real-time distance between the real-time state of production control activities and the instability domain at time is shown below.

[0076]

[0077] According to the change range of the gas concentration production control activity state in the coal mining face "P", determine the unknown coefficient =0.8, =50, then the working surface "P" is t The calculation results of the advance prediction value of the dynamic danger level of gas concentration at each moment are shown below.

[0078]

[0079] The range of the gas concentration dynamic hazard advance prediction value is [0, 1], and the threshold is set to 0.8. t The advanced prediction value of the dynamic danger level of gas concentration at the moment is 0.826, which is greater than its threshold value, and control measures should be taken immediately.

[0080] In the process of gas concentration evolving from safe to dangerous and then to over-limit, it is the changes in production activities (such as significant changes in coal mining volume, changes in gas extraction flow, changes in air volume, etc.) that lead to changes in gas concentration, which in turn lead to gas over-limit accidents. Changes in activity status are the internal cause of accidents, the internal driving force of accident evolution, and the causal precursor of changes in gas concentration. The present invention proposes to measure the dangerousness of the production activity status that affects the change in gas concentration, which is a deep-level advance prediction of the dangerousness of gas concentration. The prediction results are more accurate and more advanced, which can lay a solid foundation for the real pre-control of gas accidents.

Claims

1. A method for predicting the dynamic danger of gas concentration in a coal mining face, characterized by: The following steps are included: S100: Regularly and continuously record the monitoring data of gas concentration in the coal mining face, coal falling volume per unit time, gas extraction flow, air intake volume, and working resistance of the middle support of the working face; S200: using the monitoring data in S100, construct and determine the functional relationship between the gas concentration of the coal mining face and the amount of coal falling per unit time, the gas extraction flow rate, the air intake, and the support working resistance; The specific calculation process of step S200 is: S201: x is the gas concentration at the coal mining face, z 1 is the coal falling amount per unit time at the coal mining face, z 2 is the gas extraction flow rate, z 3 is the air volume into the working surface, z 4 is the working resistance of the middle support of the working face, then the functional relationship model between gas concentration and coal falling amount per unit time, gas extraction flow, air intake, and support working resistance is shown in Formula 1; （1） In the formula, , is the coefficient to be determined, i = 0, 1, 2, 3, 4; j = 1，2，3，4； S202: Substitute the monitoring data into Formula 1, establish a regression equation group, and determine the unknown coefficients in the formula by solving the equation group , , a clear functional relationship is obtained with gas concentration as the dependent variable and coal falling amount per unit time, gas extraction flow, air intake, and support working resistance as independent variables. G ; S300: According to the functional relationship constructed in S200, the instability domain of gas concentration control activity composed of coal falling amount per unit time, gas extraction flow rate, air intake volume and support working resistance is calculated; The specific calculation process of step S300 is: S301: According to the gas concentration warning value set at the coal mining face q and the gas concentration range of gas explosion, determine the instability region of gas concentration A ,Right now x ∈ A ; S302: All the factors that make the gas concentration in the coal mining face fall into its instability zone A The state combination of coal falling amount per unit time, gas extraction flow, air intake, and support working resistance is the instability domain of gas concentration control activity. B , the calculation process is shown in formula 2; （2） In the formula, a j is the instability region of gas concentration A The point in j = 1, 2, …, n ; S400: Calculate the real-time distance between the real-time state of the production control activity and the instability domain, and perform dimensionless normalization processing; The specific calculation process of step S400 is: S401: Set z 1( t ), z 2( t ), z 3( t ), z 4( t ) are respectively t The calculation formula of the coal falling amount per unit time, gas extraction flow, air intake and working resistance of the intermediate support at the coal mining face at all times, the real-time state of production control activities and the real-time distance between the instability domain is shown in Formula 3. （3） In the formula, bi Instability domain for production control activity state B The point in i = 1, 2, …, m ; S402: Set is the real-time state and instability domain of production control activities after dimensionless normalization B The real-time distance between them is calculated by the formula shown in Formula 4. （4） In the formula, r It is the data group number of statistics in the long-term production process; S500: using the dimensionless normalized real-time distance, calculating the dynamic danger degree of the gas concentration control activity state of the coal mining face, which is the advanced prediction value of the dynamic danger degree of the gas concentration; The specific calculation process of step S500 is: Real-time distance using dimensionless normalization , calculate the dynamic hazard of the gas concentration control activity state of the coal mining face, which is the advance prediction value of the dynamic hazard of gas concentration , the specific calculation process is shown in formula 5, （5） In the formula, for t The dimensionless normalized real-time distance at the moment after the moment; , is an undetermined coefficient, which is determined according to the change range of the gas concentration production control activity state in the coal mining face. , The value of satisfies ∈[0, 1].

2. The method for predicting the dynamic danger of gas concentration in a coal mining face according to claim 1 is characterized by: In the step S100, the data is recorded every 30 minutes, and the data is continuously monitored and counted for 10 days.

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