Goaf overlying strata three-zone identification and division method based on multi-parameter quantitative coupling

Abstract

The invention discloses a goaf overlying strata three-zone identification and division method based on multi-parameter quantitative coupling, and relates to the technical field of coal mines. The method comprises the following steps: acquiring drilling data of an overlying strata of a drill hole drilling goaf through a drill bit which is internally provided with a vibration wave monitoring module, a flushing fluid leakage monitoring module, a drilling speed measuring module and a gas flow monitoring module; determining the parameter weight of each index based on an analytic hierarchy process by means of an index weight calculation module to obtain a comprehensive physical index I value; according to a built-in calculation program of the region division module, grouping of the comprehensive physical property index data total set K is completed, and then three-dimensional partition identification and division of goaf overlying strata three zones are completed. According to the method, the drilling data obtained in real time in engineering drilling is taken as a basic parameter variable, inversion of the fracture distribution characteristics of the overlying strata in the goaf is realized, and the efficiency and the accuracy of three-zone division are effectively improved.

Description

Technical Field

[0001] The patent of this invention relates to the field of coal mining technology, specifically a method for identifying and dividing the "three zones" of overburden in goaf areas based on multi-parameter quantitative coupling. Background Art

[0002] Effective governance of coal mine goafs reflects significant engineering and environmental value and is an important measure to implement the concept of green development of mines. Accurate exploration of the development of overburden cracks in goafs is the key to effective governance of goafs. The overburden rock strata in goafs are broken to varying degrees due to mining disturbances, forming mining cracks in the overburden. As the working face advances, the cracks continue to develop and expand, destroying the geological structure of the mining area, which can easily cause underground space collapse and surface subsidence, and can easily cause geological disasters and hydrogeological problems, seriously affecting the lives of urban residents and social security and stability. Therefore, exploring the development characteristics of the overburden cracks in goafs is of great social significance for the rational planning of goaf sites and ensuring the safe and stable development of urban construction.

[0003] There are obvious differences in the damage forms of overburden strata at different levels in the goaf. According to the characteristics of crack development in the overburden, the overburden is divided into zones in space, which can be mainly divided into vertical caving zone, crack zone and curved subsidence zone, referred to as "three zones". The study of the "three zones" of overburden has attracted the attention of many researchers for many years. The detection methods of the "three zones" of overburden are diverse, which can be mainly divided into predicting the height of the water-conducting crack zone and measuring the degree of crack development in the "three zones". Among them, the most widely used methods include engineering drilling, engineering geophysical exploration, borehole imaging, downhole water pressure test method, transient electromagnetic method, microseismic monitoring, empirical formula and numerical simulation.

[0004] Among the prediction methods, the empirical formula method is widely used. Combined with the actual geological conditions of the goaf, it can predict the height range of the fault zone and the caving zone. However, this method still cannot obtain the precise development height of the "three zones" and cannot predict the specific depth. Among the actual measurement methods, borehole drilling is a traditional testing method. The development range of the "three zones" is determined only by observing the loss of flushing fluid in the borehole during drilling, the change of the borehole water level, and the fluctuation of the parameter value during drilling. However, this method is greatly affected by the geological properties, has good adaptability to medium-hard overburden, and is limited in application to soft rock formations. At the same time, this method requires specialized technicians to analyze the observation data to comprehensively judge the boundaries of the "three zones". The analysis results are not very effective and are greatly affected by the level and experience of the technicians. There are large differences in the analysis results.

[0005] Therefore, there is an urgent need to provide a technical solution to the above-mentioned deficiencies in the prior art. Summary of the invention

[0006] The purpose of this application is to provide a method for identifying and dividing the "three zones" of overburden in goaf areas based on multi-parameter quantitative coupling, so as to solve or alleviate the problems existing in the prior art.

[0007] To achieve the above objectives, this application provides the following technical solutions:

[0008] The present application provides a method for identifying and dividing the "three zones" of overburden in goaf areas based on multi-parameter quantitative coupling, which is characterized in that the method comprises the following steps:

[0009] After the S101 coal seam is mined, mining cracks are formed in the overburden due to the movement, deformation and destruction of the rock strata. According to the development of the cracks in the overburden, it can be divided into the caving zone, the fault zone and the curved sinking zone from bottom to top, namely the "three zones" of the overburden in the goaf area. During the drilling operation, the drill bit with built-in vibration wave monitoring module, flushing fluid loss monitoring module, drilling speed measurement module and gas flow monitoring module is first directly contacted with the detected coal and rock mass;

[0010] S102 When the drill bit contacts the coal rock mass and starts drilling, the sensor built into the drill bit drilling speed measurement module receives the signal and sends a start command to the speed meter, which measures and records the drilling speed value of the drill bit in real time. v At the same time, when the sensor built into the drill bit flushing fluid leakage monitoring module senses liquid outflow, the liquid flow meter in the flushing fluid leakage monitoring module is started and the flushing fluid leakage per unit time is recorded in real time. l ;

[0011] During the drilling process of the S103 drill bit, the free gas in the overlying coal and rock strata in the goaf will flow to the external working surface with low pressure through the borehole under the driving effect of the pressure gradient. At this time, when the sensor of the gas flow monitoring module in the drill bit senses the gas outflow, the gas flow meter starts to measure the borehole gas flow value I per unit time. c ;

[0012] The development of coal-rock fractures and the physical and mechanical properties of the coal-rock mass in the "three zones" of the overburden in the S104 goaf are significantly different, and the propagation speed of vibration waves in coal-rock mass with different physical and mechanical properties is significantly different. When the drill bit contacts the coal mass and performs drilling operations, vibration waves are generated due to the crushing of the coal-rock mass. The built-in detector of the vibration wave monitoring module in the drill bit monitors and records the vibration wave velocity value I in real time. p ;

[0013] S105 Then, the drilling speed value I recorded by the drilling speed measuring module is sequentially v Data set, flushing fluid leakage monitoring module records flushing fluid leakage per unit time I l Data set, borehole gas flow value recorded by gas flow monitoring module Ic Data set and shock wave velocity value I recorded by the shock wave monitoring module p The data set is transmitted to the indicator weight calculation module to complete the determination of the weight of each indicator parameter, and then calculate the comprehensive physical property parameter I value representing the physical and mechanical properties of the coal and rock mass that the drill bit contacts per unit time;

[0014] S106 After the number of drilling operations for the overburden in the goaf area set according to the design plan is completed, the comprehensive physical property index data set K composed of the comprehensive physical property index value I obtained during the drilling of each hole is transmitted to the regional division module, and the threshold is further set according to the built-in I parameter value range to complete the three-dimensional zoning identification and division of the overburden "three zones" in the goaf area;

[0015] The device for identifying and dividing the "three zones" of overburden in goaf areas based on multi-parameter quantitative coupling is characterized in that the device mainly includes a vibration wave monitoring module, a flushing fluid leakage monitoring module, a drilling speed measurement module, a gas flow monitoring module, an indicator weight calculation module and a regional division module.

[0016] Preferably, the drill bit is equipped with a drilling speed measuring module, a flushing fluid leakage monitoring module, a gas flow monitoring module and a vibration wave monitoring module, wherein the drilling speed measuring module has a built-in tachometer which is mainly used to monitor the speed fluctuation of the drill bit during drilling into the coal and rock mass, and to measure and record the drilling speed value of the drill bit in real time. v ; The curved sinking zone basically moves as a whole, with local delamination cracks. The drilling speed tends to be stable during the drilling process, with only slight fluctuations in some areas; the fault zone is greatly affected by mining disturbance, the cracks are significantly developed, the drilling speed is greatly increased, and the drilling speed fluctuates significantly; the collapsed zone at the bottom of the goaf is mainly composed of collapsed rock blocks, with many accumulated holes and gaps between the rock blocks. Compared with normal strata, the drilling speed will be significantly increased and there will be large fluctuations. According to the drilling speed value I of the drill bit during drilling at different positions of the overlying rock strata in the goaf v The changes in the overburden in the goaf can be used to realize the “three zones” division.

[0017] Preferably, the flushing fluid leakage monitoring module mainly includes a liquid flow meter, a data processor and a data storage device, wherein the liquid flow meter is mainly used to record the change in the leakage of flushing fluid flowing through the borehole pipe during the drilling of the drill bit; due to the significant differences in the development of cracks in the "three zones" of the overburden in the goaf area, the flushing fluid leakage during the drilling of the drill bit will also be significantly different, the curved sinking zone is not greatly affected by mining, and the cracks are less developed. Only the delamination cracks are locally filled with water and are not connected with the fault zone. The overall drilling flushing fluid loss in the curved sinking zone tends to be stable; in the fault zone located in the middle of the "three zones", the vertical cracks gradually develop and strengthen, which promotes the connection between the delamination cracks and the vertical cracks, and the overall water conductivity is significantly increased, providing an advantageous channel for the liquid to flow into the lower goaf. Therefore, when the drill bit drills into the fault zone, the flushing fluid loss will suddenly increase significantly, and the flushing fluid loss per unit time is I l The fluctuation is large; the collapse zone is affected by the accumulation of coal and rock blocks and has stronger connectivity. When the borehole is drilled into the collapse zone, the flushing fluid loss is large, or even all lost. Therefore, the flushing fluid loss per unit time during the drilling of the "three zones" of the overburden in the goaf is I l There are significant differences.

[0018] Preferably, the shock wave monitoring module mainly includes three parts: a detector, a data processor and a data storage device, wherein the detector is mainly used to receive shock waves during the drilling process of the borehole; the technical principle of the shock wave monitoring module is mainly: the shock waves generated by the contact and damage of the drill bit and the coal body during the drilling process are used as the main source of the earthquake, and the wave velocity distribution is inverted according to the distance L between the detector and the source and the time T received by the detector. The specific relationship is as follows: Where, d ij is the length of the i-th shock wave ray passing through the j-th grid, N is the total number of rays, and M is the number of grids. There are obvious differences in the propagation speed of shock waves in coal and rock masses with different structures. For homogeneous, isotropic continuous media, the relationship between the propagation characteristics of shock waves and the physical and mechanical parameters of coal and rock masses can be expressed as follows: In the formula, v p , v S are the propagation velocities of P waves and S waves respectively; ν is Poisson's ratio, 0≤v≤0.5; E is the elastic modulus; ρ is the density of coal rock medium. Therefore, the physical and mechanical properties of coal and rock mass can be determined according to the characteristics of the change in the propagation velocity of the shock wave. There are obvious differences in the development of fractures, mechanical strength characteristics and stress distribution of the coal and rock mass in the "three zones" of the overburden in the goaf area. Therefore, according to the value of the borehole shock wave velocity I pBy analyzing the changes in the overburden in the goaf, the “three zones” of the overburden can be identified and differentiated.

[0019] Preferably, the data processor built into the index weight calculation module determines the drilling speed I and the drilling speed I of the drill bit by using a hierarchical analysis method. v The weight value α, flushing fluid loss I l The weight value β, the borehole gas flow I c The weight value λ and the vibration wave speed I p The weight value μ is used to calculate the comprehensive physical property parameter I value representing the physical and mechanical properties of the coal and rock mass that the drill bit contacts per unit time. The expression of I is as follows: I=ξ(αI v +βI l +λI c +μI p ) Where, I——comprehensive physical property parameters; I v ——Drilling speed, m / min; I l ——Flushing fluid leakage, mL / min; I c ——Drilling gas flow rate, mL / min; I p ——vibration wave velocity, m / s; ξ——comprehensive index coefficient of regional risk; α, β, λ, μ——weight coefficients of each sub-indicator, where α+β+λ+μ=1;

[0020] Preferably, the regional division module is based on a data set K composed of comprehensive physical property index values ​​I obtained during the drilling of all boreholes, and takes the interval threshold range set according to the size characteristics of the comprehensive physical property index values ​​I as the basic division basis, and combined with the distribution characteristics of the "three zones" of overburden in the goaf, the total comprehensive physical property index data set K composed of the comprehensive physical property index values ​​I obtained during the drilling of all boreholes is divided into three subsets, namely, the curved subsidence zone data subset W, the fracture zone data subset L and the caving zone data subset M, thereby completing the three-dimensional zoning and precise identification and division of the "three zones" of overburden in the goaf.

[0021] Preferably, during the drilling process of overburden drilling in the goaf area, due to the significant differences in the fracture development structure composition of the coal rock mass at different positions where the drill bit contacts and the mechanical properties of the coal rock mass itself, the drill bit drilling speed value I recorded by the drill bit built-in drilling speed measurement module is v , the flushing liquid leakage monitoring module records the flushing liquid leakage per unit time I l , the borehole gas flow value I recorded by the gas flow monitoring module c and the vibration wave velocity value I recorded by the vibration wave monitoring modulep There are obvious differences. Based on this, the comprehensive physical property parameter I value reflecting the coal body characteristics at a specific location under different drilling distances in the same drilling hole per unit time can be calculated according to formula (1). When the drilling operation of the drilling hole is completed at the set distance, as the output data point I i Increase, and further form the data subset K i (I 1 ,I 2 ,I 3 ,I 4 , ...), and different drilling data subsets K i By collecting them together, we can form a comprehensive physical property index data set K (K 1 , K 2 , K 3 , K 4 , ...); combined with the distribution characteristics of overburden cracks in the goaf area and the differences in the physical property parameters of the overlying coal rock mass itself, the total set of comprehensive physical property index data K obtained during the drilling process of all boreholes in the goaf overburden drilling area is divided into three subsets according to the value of the comprehensive physical property index I, namely, the curved subsidence zone data subset W (W 1 ,W 2 ,W 3 ), fracture zone data subset L(L 1 ,L 2 ,L 3 ) and the caving zone data subset M(M 1 ,M 2 ,M 3 ), thereby realizing the accurate identification and division of the three-dimensional zoning of the “three zones” of the overburden in the goaf area.

[0022] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] The present invention is based on the distribution characteristics of overburden cracks in goaf areas, and uses the drilling data obtained in real time during engineering drilling as the basic parameter variables. It innovatively fully considers the changes in the drill bit drilling speed, flushing fluid leakage, borehole gas flow rate and vibration wave velocity with the development characteristics of overburden cracks during the drilling process, so as to achieve the inversion of the distribution characteristics of cracks in the overburden strata in the goaf area, and establishes a precise identification and division method for the three-dimensional partitioning of the "three zones" of the overburden in the goaf area based on multi-parameter coupling. The present invention obtains drilling data in real time during the drilling process of the drill bit, and fully considers the response degree of multiple parameters to the overburden cracks to assign weights, giving full play to the timeliness and accuracy of the drilling data, improving the efficiency and accuracy of the "three zones" division, and at the same time, it is of great significance to promote the development of intelligent management of coal mine goaf areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1This is a flow chart of the method for identifying and dividing the "three zones" of overburden in goaf areas based on multi-parameter quantitative coupling of the present invention;

[0025] Figure 2 This is a schematic diagram of the composition of the fissure development comprehensive index data set of the present invention;

[0026] Figure 3 This is a schematic diagram of the development and division of the fracture zone of the present invention;

[0027] Figure 4 It is a schematic diagram of the device for identifying and dividing the "three zones" of overburden in goaf area based on multi-parameter quantitative coupling of the present invention; DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with the embodiments and drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be understood that terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “top”, “bottom”, “inside” and “outside” indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device, component or structure must have a specific direction, be constructed or operate in a specific direction, and should not be understood as a limitation on the present invention.

[0030] The specific implementation method of the present invention will be further described below in conjunction with the accompanying drawings.

[0031] like Figure 1-4 As shown, the present invention provides a method for identifying and dividing the "three zones" of overburden in goaf areas based on multi-parameter quantitative coupling, characterized in that the method comprises the following steps:

[0032] After the S101 coal seam is mined, mining cracks are formed in the overburden due to the movement, deformation and destruction of the rock strata. According to the development of the cracks in the overburden, it can be divided into the caving zone, the fault zone and the curved sinking zone from bottom to top, namely the "three zones" of the overburden in the goaf area. During the drilling operation, the drill bit with built-in vibration wave monitoring module, flushing fluid loss monitoring module, drilling speed measurement module and gas flow monitoring module is first directly contacted with the detected coal and rock mass;

[0033] S102 When the drill bit contacts the coal rock mass and starts drilling, the sensor built into the drill bit drilling speed measurement module receives the signal and sends a start command to the speed meter, which measures and records the drilling speed value of the drill bit in real time. v At the same time, when the sensor built into the drill bit flushing fluid leakage monitoring module senses liquid outflow, the liquid flow meter in the flushing fluid leakage monitoring module is started and the flushing fluid leakage per unit time is recorded in real time. l ;

[0034] During the drilling process of the S103 drill bit, the free gas in the overlying coal and rock strata in the goaf will flow to the external working surface with low pressure through the borehole under the driving effect of the pressure gradient. At this time, when the sensor of the gas flow monitoring module in the drill bit senses the gas outflow, the gas flow meter starts to measure the borehole gas flow value I per unit time. c ;

[0035] The development of coal-rock fractures and the physical and mechanical properties of the coal-rock mass in the "three zones" of the overburden in the S104 goaf are significantly different, and the propagation speed of vibration waves in coal-rock mass with different physical and mechanical properties is significantly different. When the drill bit contacts the coal mass and performs drilling operations, vibration waves are generated due to the crushing of the coal-rock mass. The built-in detector of the vibration wave monitoring module in the drill bit monitors and records the vibration wave velocity value I in real time. p ;

[0036] S105 Then, the drilling speed value I recorded by the drilling speed measuring module is sequentially v Data set, flushing fluid leakage monitoring module records flushing fluid leakage per unit time I l Data set, borehole gas flow value recorded by gas flow monitoring module I c Data set and shock wave velocity value I recorded by the shock wave monitoring module p The data set is transmitted to the indicator weight calculation module to complete the determination of the weight of each indicator parameter, and then calculate the comprehensive physical property parameter I value representing the physical and mechanical properties of the coal and rock mass that the drill bit contacts per unit time;

[0037] S106 After completing the number of drilling operations for the overburden in the goaf area set according to the design plan, the total set K of comprehensive physical property index data composed of the comprehensive physical property index value I obtained during the drilling of each hole is transmitted to the regional division module, and the threshold is further set according to the built-in I parameter value range to complete the three-dimensional zoning identification and division of the "three zones" of the overburden in the goaf area.

[0038] The device for identifying and dividing the "three zones" of overburden in goaf areas based on multi-parameter quantitative coupling is characterized in that the device mainly includes a vibration wave monitoring module, a flushing fluid leakage monitoring module, a drilling speed measurement module, a gas flow monitoring module, an indicator weight calculation module and a regional division module.

[0039] like Figure 2-4 As shown, the drill bit is equipped with a drilling speed measurement module, a flushing fluid leakage monitoring module, a gas flow monitoring module and a vibration wave monitoring module, wherein the drilling speed measurement module has a built-in tachometer which is mainly used to monitor the speed fluctuation of the drill bit during drilling into the coal and rock mass, and to measure and record the drilling speed value of the drill bit in real time. v ; The curved sinking zone basically moves as a whole, with local delamination cracks. The drilling speed tends to be stable during the drilling process, with only slight fluctuations in some areas; the fault zone is greatly affected by mining disturbance, the cracks are significantly developed, the drilling speed is greatly increased, and the drilling speed fluctuates significantly; the collapsed zone at the bottom of the goaf is mainly composed of collapsed rock blocks, with many accumulated holes and gaps between the rock blocks. Compared with normal strata, the drilling speed will be significantly increased and there will be large fluctuations. According to the drilling speed value I of the drill bit during drilling at different positions of the overlying rock strata in the goaf v The changes in the overburden in the goaf can be used to realize the “three zones” division.

[0040] like Figure 1 and 4 As shown in the figure, the flushing fluid leakage monitoring module mainly includes a liquid flow meter, a data processor and a data storage device, wherein the liquid flow meter is mainly used to record the change in the leakage of flushing fluid flowing through the borehole pipe during the drilling of the drill bit; due to the significant differences in the development of cracks in the "three zones" of the overburden in the goaf area, the flushing fluid leakage during the drilling of the drill bit will also be significantly different, the curved sinking zone is not greatly affected by mining, the cracks are less developed, only the delamination cracks are locally filled with water, and are not connected with the fault zone, and the drilling flushing fluid loss in the curved sinking zone tends to be stable as a whole; in the fault zone located in the middle of the "three zones", the vertical cracks gradually develop and strengthen, which promotes the connection between the delamination cracks and the vertical cracks, and the overall water conductivity is significantly increased, providing an advantageous channel for the liquid to flow into the lower goaf. Therefore, when the drill bit drills into the fault zone, the flushing fluid loss will suddenly increase significantly, and the flushing fluid loss per unit time I l The fluctuation is large; the collapse zone is affected by the accumulation of coal and rock blocks and has stronger connectivity. When the borehole is drilled into the collapse zone, the flushing fluid loss is large, or even all lost. Therefore, the flushing fluid loss per unit time during the drilling of the "three zones" of the overburden in the goaf is I l There are significant differences.

[0041] like Figure 4As shown in FIG. 1 , the vibration wave monitoring module mainly includes three parts: a detector, a data processor and a data storage device, wherein the detector is mainly used to receive vibration waves during the drilling process of the borehole; the technical principle of the vibration wave monitoring module is mainly: the vibration waves generated by the contact and damage of the drill bit and the coal body during the drilling process are used as the main source of vibration, and the wave velocity distribution is inverted according to the distance L between the detector and the source and the time T received by the detector. The specific relationship is as follows: Where, d ij is the length of the i-th shock wave ray passing through the j-th grid, N is the total number of rays, and M is the number of grids. There are obvious differences in the propagation speed of shock waves in coal and rock masses with different structures. For homogeneous, isotropic continuous media, the relationship between the propagation characteristics of shock waves and the physical and mechanical parameters of coal and rock masses can be expressed as follows: In the formula, v p , v S are the propagation velocities of P waves and S waves respectively; v is Poisson's ratio, 0≤v≤0.5; E is the elastic modulus; ρ is the density of coal rock medium. Therefore, the physical and mechanical properties of coal and rock mass can be determined according to the characteristics of the change in the propagation velocity of the shock wave. There are obvious differences in the development of fractures, mechanical strength characteristics and stress distribution of the coal and rock mass in the "three zones" of the overburden in the goaf area. Therefore, according to the value of the borehole shock wave velocity I p By analyzing the changes in the overburden in the goaf, the “three zones” of the overburden can be identified and differentiated.

[0042] like Figure 1 and 4 As shown, the data processor built into the index weight calculation module determines the drilling speed I and v The weight value α, flushing fluid loss I l The weight value β, the borehole gas flow I c The weight value λ and the vibration wave speed I p The weight value μ is used to calculate the comprehensive physical property parameter I value representing the physical and mechanical properties of the coal and rock mass that the drill bit contacts per unit time. The expression of I is as follows: I=ξ(αI v +βI l +λI c +μI p ) Where, I——comprehensive physical property parameters; I v ——Drilling speed, m / min; ll ——Flushing fluid leakage, mL / min; I c ——Drilling gas flow rate, mL / min; I p ——vibration wave velocity, m / s; ξ——comprehensive index coefficient of regional risk; α, β, λ, μ——weight coefficients of each sub-indicator, where α+β+λ+μ=1;

[0043] like Figure 2-3 As shown, the regional division module is based on the data set K composed of the comprehensive physical property index values ​​I obtained during the drilling of all boreholes, and takes the interval threshold range set according to the size characteristics of the comprehensive physical property index values ​​I as the basic division basis. Combined with the distribution characteristics of the "three zones" of the overburden in the goaf, the total comprehensive physical property index data set K composed of the comprehensive physical property index values ​​I obtained during the drilling of all boreholes is divided into three subsets, namely, the curved subsidence zone data subset W, the fracture zone data subset L and the caving zone data subset M, thereby completing the three-dimensional zoning and precise identification and division of the "three zones" of the overburden in the goaf.

[0044] like Figure 1-3 As shown in the figure, during the drilling process of overburden drilling in the goaf area, due to the significant differences in the fracture development structure composition of the coal rock mass at different positions where the drill bit contacts and the mechanical properties of the coal rock mass itself, the drill bit drilling speed value I recorded by the drill bit built-in drilling speed measurement module is v , the flushing liquid leakage monitoring module records the flushing liquid leakage per unit time I l , the borehole gas flow value I recorded by the gas flow monitoring module c and the vibration wave velocity value I recorded by the vibration wave monitoring module p There are obvious differences. Based on this, the comprehensive physical property parameter I value reflecting the coal body characteristics at a specific location under different drilling distances in the same drilling hole per unit time can be calculated according to formula (1). When the drilling operation of the drilling hole is completed at the set distance, as the output data point I i Increase, and further form the data subset K i (I 1 ,I 2 ,I 3 ,I 4 , ...), and different drilling data subsets K i By collecting them together, we can form a comprehensive physical property index data set K (K 1 , K 2 , K 3 , K 4, ...); combined with the distribution characteristics of overburden cracks in the goaf area and the differences in the physical property parameters of the overlying coal rock mass itself, the total set of comprehensive physical property index data K obtained during the drilling process of all boreholes in the goaf overburden drilling area is divided into three subsets according to the value of the comprehensive physical property index I, namely, the curved subsidence zone data subset W (W 1 ,W 2 ,W 3 ), fracture zone data subset L(L 1 ,L 2 ,L 3 ) and the caving zone data subset M(M 1 ,M 2 ,M 3 ), thereby realizing the accurate identification and division of the three-dimensional zoning of the “three zones” of the overburden in the goaf area.

[0045] At this point, those skilled in the art should recognize that, although the exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the contents disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A method for identifying and dividing the "three zones" of overburden in goaf areas based on multi-parameter quantitative coupling, characterized by: The method comprises the following steps: After the S101 coal seam is mined, due to the movement, deformation and destruction of the rock formation, mining cracks are formed in the overburden. According to the development of the cracks in the overburden, it can be divided into the caving zone, the fault zone and the curved sinking zone from bottom to top, namely the "three zones" of the overburden in the goaf area. During the drilling operation, the drill bit with built-in vibration wave monitoring module, flushing fluid loss monitoring module, drilling speed measurement module and gas flow monitoring module is first directly contacted with the detected coal and rock mass; S102 When the drill bit contacts the coal rock mass and starts drilling, the sensor built into the drill bit drilling speed measurement module receives the signal and sends a start command to the speed meter, which measures and records the drilling speed value of the drill bit in real time. v At the same time, when the sensor built into the drill bit flushing fluid leakage monitoring module senses liquid outflow, the liquid flow meter in the flushing fluid leakage monitoring module is started and the flushing fluid leakage per unit time is recorded in real time. l ; During the drilling process of the S103 drill bit, the free gas in the overlying coal and rock strata in the goaf will flow to the external working surface with low pressure through the borehole under the driving effect of the pressure gradient. At this time, when the sensor of the gas flow monitoring module in the drill bit senses the gas outflow, the gas flow meter starts to measure the borehole gas flow value I per unit time. c ; The development of coal-rock fractures and the physical and mechanical properties of the coal-rock mass in the "three zones" of the overburden in the S104 goaf are significantly different, and the propagation speed of vibration waves in coal-rock mass with different physical and mechanical properties is significantly different. When the drill bit contacts the coal mass and performs drilling operations, vibration waves are generated due to the crushing of the coal-rock mass. The built-in detector of the vibration wave monitoring module in the drill bit monitors and records the vibration wave velocity value I in real time. p ; S105 Then, the drilling speed value I recorded by the drilling speed measuring module is sequentially v Data set, flushing fluid leakage monitoring module records flushing fluid leakage per unit time I l Data set, borehole gas flow value recorded by gas flow monitoring module I c Data set and shock wave velocity value I recorded by the shock wave monitoring module p The data set is transmitted to the index weight calculation module to complete the determination of the weight of each index parameter, and then calculate the comprehensive physical property index I value representing the physical and mechanical properties of the coal and rock mass that the drill bit contacts per unit time; S106 After the number of drilling operations for the overburden in the goaf area set according to the design plan is completed, the comprehensive physical property index data set K composed of the comprehensive physical property index I value obtained during the drilling process of each borehole is transmitted to the regional division module, and the threshold is further set according to the built-in I parameter value range to complete the grouping of the comprehensive physical property index data set K, thereby completing the three-dimensional zoning identification and division of the "three zones" of the overburden in the goaf area; The method for identifying and dividing the "three zones" of overburden in goaf areas based on multi-parameter quantitative coupling is completed by relying on a device for identifying and dividing the "three zones" of overburden in goaf areas based on multi-parameter quantitative coupling, which is characterized in that the device mainly includes a shock wave monitoring module, a flushing fluid leakage monitoring module, a drilling speed measurement module, a gas flow monitoring module, an indicator weight calculation module and a regional division module.

2. The method for identifying and dividing the "three zones" of overburden in goaf area based on multi-parameter quantitative coupling according to claim 1 is characterized in that: The drill bit is equipped with a drilling speed measurement module, a flushing fluid leakage monitoring module, a gas flow monitoring module and a vibration wave monitoring module. The drilling speed measurement module has a built-in tachometer which is mainly used to monitor the speed fluctuation of the drill bit during drilling into the coal and rock mass, and to measure and record the drilling speed value of the drill bit in real time. v ; The curved sinking zone basically moves as a whole, with local delamination cracks. The drilling speed tends to be stable during the drilling process, with only slight fluctuations in some areas; the fault zone is greatly affected by mining disturbance, the cracks are significantly developed, the drilling speed is greatly increased, and the drilling speed fluctuates significantly; the collapsed zone at the bottom of the goaf is mainly composed of collapsed rock blocks, with many accumulated holes and gaps between the rock blocks. Compared with normal strata, the drilling speed will be significantly increased and there will be large fluctuations. According to the drilling speed value I of the drill bit during drilling at different positions of the overlying rock strata in the goaf v The "three zones" division of the overburden in the goaf can be realized based on the changes in the overburden.

3. The method for identifying and dividing the "three zones" of overburden in goaf area based on multi-parameter quantitative coupling according to claim 1 is characterized in that: The flushing fluid leakage monitoring module mainly includes a liquid flow meter, a data processor and a data storage device, wherein the liquid flow meter is mainly used to record the change in the leakage of flushing fluid flowing through the borehole pipe during the drilling of the drill bit; due to the significant differences in the development of cracks in the "three zones" of the overburden in the goaf area, the flushing fluid leakage during the drilling of the drill bit will also be significantly different, the curved sinking zone is not greatly affected by mining, and the cracks are less developed. Only the delamination cracks are locally filled with water and are not connected with the fault zone. The overall drilling flushing fluid leakage in the curved sinking zone tends to be stable; in the fault zone located in the middle of the "three zones", the vertical cracks gradually develop and strengthen, which promotes the connection between the delamination cracks and the vertical cracks, and the overall water conductivity is significantly increased, providing an advantageous channel for the liquid to flow into the lower goaf. Therefore, when the drill bit drills into the fault zone, the flushing fluid leakage will suddenly increase significantly, and the flushing fluid leakage per unit time is I l The fluctuation is large; the collapse zone is affected by the accumulation of coal and rock blocks and has stronger connectivity. When the borehole is drilled into the collapse zone, the flushing fluid loss is large, or even all lost. Therefore, the flushing fluid loss per unit time during the drilling of the "three zones" of the overburden in the goaf is I l There are significant differences.

4. The method for identifying and dividing the "three zones" of overburden in goaf area based on multi-parameter quantitative coupling according to claim 1 is characterized in that: The shock wave monitoring module mainly includes three parts: a detector, a data processor and a data storage device, wherein the detector is mainly used to receive shock waves during the drilling process; the technical principle of the shock wave monitoring module is mainly: the shock waves generated by the contact and damage of the drill bit and the coal body during the drilling process are used as the main source of vibration, and the wave velocity distribution is inverted according to the distance L between the detector and the source and the time T received by the detector. The specific relationship is as follows: Where, d ij is the length of the i-th shock wave ray passing through the j-th grid, N is the total number of rays, and M is the number of grids. There are obvious differences in the propagation speed of shock waves in coal and rock masses with different structures. For homogeneous, isotropic continuous media, the relationship between the propagation characteristics of shock waves and the physical and mechanical parameters of coal and rock masses can be expressed as follows: In the formula, v p , v S are the propagation velocities of P waves and S waves respectively; v is Poisson's ratio, 0≤v≤0.5; E is the elastic modulus; ρ is the density of coal rock medium. Therefore, the physical and mechanical properties of coal and rock mass can be determined according to the characteristics of the change in the propagation velocity of the shock wave. There are obvious differences in the development of fractures, mechanical strength characteristics and stress distribution of the coal and rock mass in the "three zones" of the overburden in the goaf area. Therefore, according to the value of the borehole shock wave velocity I p By analyzing the changes in the overburden rock in the goaf, the "three zones" of the overburden rock can be identified and differentiated.

5. The method for identifying and dividing the "three zones" of overburden in goaf area based on multi-parameter quantitative coupling according to claim 1 is characterized in that: The data processor built into the index weight calculation module determines the drilling speed I and the drilling speed I of the drill bit by using the hierarchical analysis method. v The weight value α, flushing fluid loss I l The weight value β, the borehole gas flow I c The weight value λ and the vibration wave speed I p The weight value μ is used to calculate the comprehensive physical property index I value representing the physical and mechanical properties of the coal and rock mass that the drill bit contacts per unit time. The expression of I is as follows: I=ξ(αI v +βI l +λI c +μI p ) In the formula, I——comprehensive physical property index; I v ——Drilling speed, m / min; I l ——Flushing fluid leakage, mL / min; I c ——Drilling gas flow rate, mL / min; I p ——vibration wave velocity, m / s; ξ——comprehensive index coefficient of regional risk; α, β, λ, μ——weight coefficients of each sub-indicator, among which α+β+λ+μ=1.

6. The method for identifying and dividing the "three zones" of overburden in goaf area based on multi-parameter quantitative coupling according to claim 1 is characterized in that: The regional division module is based on the data set K composed of the comprehensive physical property index values ​​I obtained during the drilling of all boreholes, and takes the interval threshold range set according to the size characteristics of the comprehensive physical property index values ​​I as the basic division basis. Combined with the distribution characteristics of the "three zones" of the overburden in the goaf, the total set K of comprehensive physical property index data composed of the comprehensive physical property index values ​​I obtained during the drilling of all boreholes is divided into three subsets according to the value size, namely, the curved subsidence zone data subset W, the fracture zone data subset L and the caving zone data subset M, thereby completing the three-dimensional zoning and precise identification and division of the "three zones" of the overburden in the goaf.

7. The method for identifying and dividing the "three zones" of overburden in goaf area based on multi-parameter quantitative coupling according to claim 1 is characterized in that: During the drilling process of overburden drilling in the goaf area, due to the significant differences in the fracture development structure composition of the coal rock mass at different positions where the drill bit contacts and the mechanical properties of the coal rock mass itself, the drill bit drilling speed value I recorded by the drill bit built-in drilling speed measurement module is v , the flushing liquid leakage monitoring module records the flushing liquid leakage per unit time I l , the borehole gas flow value I recorded by the gas flow monitoring module c and the vibration wave velocity value I recorded by the vibration wave monitoring module p There are obvious differences. Based on this, according to formula (1), the comprehensive physical property index I value reflecting the characteristics of the coal body at a specific location under different drilling distances in the same drilling hole per unit time can be calculated. When the drilling operation of the set distance is completed, as the output data point I i Increase, and then the drilling data subset K can be further formed i (I1, I2, I3, I4, ...), and different drilling data subsets K i By collecting the data, a comprehensive physical property index data set K (K1, K2, K3, K4, ...) reflecting the properties of the coal rock mass in the overall drilling area of ​​the goaf overburden can be formed; combined with the distribution characteristics of the overburden cracks in the goaf and the differences in the physical property parameters of the overlying coal rock mass itself, the comprehensive physical property index data set K obtained during the drilling process of all boreholes in the goaf overburden drilling area is divided into three subsets according to the size of the comprehensive physical property index value I, namely, the curved subsidence zone data subset W (W1, W2, W3), the fracture zone data subset L (L1, L2, L3) and the caving zone data subset M (M1, M2, M3), thereby realizing the accurate identification and division of the three-dimensional zoning of the "three zones" of the goaf overburden.

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