A method and system for evaluating the grouting effect of a coal mine underground goaf

Abstract

The application relates to a coal mine underground goaf grouting effect evaluation method and system. Through directional drilling of a borehole, long-distance detection and evaluation of the grouting effect of a goaf can be realized at one time according to the size of the goaf; the engineering parameters of directional drilling can evaluate the coagulation effect of goaf grouting; a millimeter wave radar wave detection method can detect the state of the borehole wall, and the grouting effect can be intuitively analyzed according to the form of the borehole wall; a meter-level radar wave detection method can detect and evaluate the grouting effect within a certain range around the borehole; according to the detection of multiple boreholes in the goaf grouting area, the application finally realizes fine detection and evaluation of the entire goaf in the whole range, and the borehole drilled by directional drilling can be used for remedial grouting in the area with poor grouting effect after the evaluation is completed.

Description

Technical Field

[0001] This application relates to the field of subsidence prevention and control in coal mine goaf areas, specifically to a method and system for evaluating the grouting effect in underground coal mine goaf areas. Background Technology

[0002] After coal mining, a large number of goaf areas are left underground. Many coal mines use non-filling mining methods during the mining process, which will create a large number of large goaf areas. Large goaf areas are prone to water enrichment, which threatens the mining of surrounding coal mines, and can also cause ground subsidence, damage the surface environment, and have a great impact on the surrounding residents and ecological environment.

[0003] Grouting is a common method in goaf treatment. The main methods for evaluating the grouting effect are as follows: (1) Grouting filling rate analysis method: Collect relevant engineering parameters for analysis during the grouting process, including PQt curve analysis method, grouting volume distribution characteristic method, and grout filling coefficient inverse method. Among them, the PQt curve analysis method reflects the filling situation through the relationship curve of grouting pressure and speed, but in special sections such as faults, abnormal trends may occur, making it impossible to correctly judge whether the reinforcement is successful. The grouting volume distribution characteristic method intuitively shows the grouting distribution state, but cannot explain the quality of reinforcement. The grouting filling rate analysis method can quantitatively reflect the grout filling situation, but ignores the diffusion form in different media and the accurate determination of grout loss rate. (2) Inspection hole method: As a method recommended by the standard, the inspection hole method evaluates the grouting effect by setting inspection holes after grouting, and carrying out work such as hole observation, core sampling, grouting test and permeability coefficient measurement. (3) Deformation monitoring method: By setting up surface deformation monitoring points within the affected area of ​​the goaf, collecting surface deformation observation data before and after treatment and during construction, and analyzing and evaluating the reinforcement effect, this method is not effective for evaluating the surface changes of the goaf with little change, and cannot directly evaluate the grouting effect inside the grouting. (4) Conventional geophysical exploration method: Geophysical exploration techniques such as direct current method, electromagnetic wave CT, and seismic wave CT are used before and after grouting. By comparing and analyzing the filling effect of grout on the collapse fault zone, the direct current method has a limited detection distance and cannot conduct long-distance detection for large goaf areas. Electromagnetic wave CT requires cross-hole or cross-tunnel detection, which is difficult to construct. At the same time, electromagnetic waves cannot penetrate large goaf areas. Seismic wave CT has low detection accuracy due to the large wavelength of seismic waves, and has poor detection of local effects in goaf areas. It also cannot evaluate the grouting effect inside the goaf. (5) Core drilling: The presence of grout stones can be directly observed by core drilling, thereby evaluating the grouting effect. This method is intuitive but destructive, localized, and costly, and cannot fully reflect the effect of the entire grouting area. (6) Water pressure test: The grouting filling effect can be indirectly evaluated by the changes in unit water absorption and permeability coefficient reflected by water pressure tests before and after grouting. This method may have problems such as not being able to accurately simulate actual grouting conditions, or the difference between water flow and grout flow in porous media. Summary of the Invention

[0004] To overcome at least one deficiency in the prior art, this application provides a method and system for evaluating the grouting effect in underground goaf areas of coal mines.

[0005] Firstly, a method for evaluating the grouting effect in underground goaf areas of coal mines is provided, including:

[0006] Step S1: Design the trajectory of multiple long-distance boreholes based on the information of the goaf area;

[0007] Step S2: Based on the trajectory, perform directional drilling of any long-distance borehole and obtain the engineering parameters during the directional drilling process, including drilling pressure, rotation speed and pump displacement.

[0008] Step S3: During the directional drilling process, millimeter-level radar wave detectors and meter-level radar wave detectors are used to detect long-distance boreholes to obtain millimeter-level radar wave detection data and meter-level radar wave detection data.

[0009] Step S4: Filter, normalize, and calculate the standard score of the engineering parameters to obtain the first grouting effect evaluation index parameters;

[0010] Step S5: Generate a millimeter-level radar wave detection data map of the borehole wall based on the millimeter-level radar wave detection data, and calculate the second grouting effect evaluation index parameters based on the millimeter-level radar wave detection data map;

[0011] Step S6: Perform full waveform inversion imaging on the meter-level radar wave detection data to obtain the distribution image of the medium surrounding the borehole detection, and calculate the third grouting effect evaluation index parameters based on the distribution image of the medium surrounding the borehole detection.

[0012] Step S7: Weight the first grouting effect evaluation index parameter, the second grouting effect evaluation index parameter, and the third grouting effect evaluation index parameter to obtain the comprehensive evaluation index parameter for long-distance drilling.

[0013] Step S8: Determine the grouting effect level of long-distance boreholes based on the comprehensive evaluation index parameters and the grouting effect grading standard.

[0014] Step S9: Update the grouting effect grading standard based on the comprehensive evaluation index parameters and grouting effect level;

[0015] Step S10: Determine whether all long-distance boreholes have been directionally drilled. If yes, obtain the grouting effect level of each long-distance borehole and proceed to step S11. If no, return to step S2.

[0016] Step S11: Based on the grouting effect level of each long-distance borehole, the Kriging interpolation method is used to determine the grouting effect level of the undetected area of ​​the goaf.

[0017] In one embodiment, step S1, designing the trajectories of multiple long-distance boreholes based on goaf information, includes:

[0018] The number of long-distance boreholes (N) is determined based on the size of the goaf. B The following formula is used:

[0019]

[0020] Where V is the volume of the goaf, L is the length of the long-distance borehole, and R is the detection radius of the long-distance borehole;

[0021] Determine the distribution location of long-distance boreholes; the distribution location includes the center of the goaf, and the locations in the east, south, west, and north directions with the center of the goaf as a reference;

[0022] Multiple long-distance boreholes are located at the same opening point and are distributed in a feather-like pattern; or multiple long-distance boreholes are located at different opening points and are distributed in parallel.

[0023] In one embodiment, step S3, using millimeter-level and meter-level radar wave detectors to detect long-distance boreholes, includes:

[0024] The depth of millimeter-level and meter-level radar wave detectors in long-distance boreholes is marked with dots, and the depth data is recorded in the form of timestamps.

[0025] Data collected by millimeter-level and meter-level radar wave detectors are stored using timestamps.

[0026] The data collected by the millimeter-level radar wave detector and the data collected by the meter-level radar wave detector are matched with the depth data according to the timestamp to obtain the millimeter-level radar wave detection data and meter-level radar wave detection data distributed along the depth.

[0027] In one embodiment, step S4 involves filtering, normalizing, and calculating standard scores for the engineering parameters to obtain the first grouting effect evaluation index parameters, including:

[0028] The engineering parameters at each measuring point are filtered to obtain the filtered engineering parameters.

[0029] The filtered engineering parameters are normalized to obtain the normalized engineering parameters.

[0030] The standard score is calculated based on the normalized engineering parameters; the standard score includes the standard score for pressure, the standard score for speed, and the standard score for pump displacement.

[0031] The average values ​​of the standard scores of pressure, rotation speed, and pump displacement are calculated to obtain the grouting effect evaluation index parameters for each measuring point.

[0032] Calculate the mean value of the grouting effect evaluation index parameters for all measuring points to obtain the first grouting effect evaluation index parameter.

[0033] In one embodiment, the engineering parameters of each measuring point are filtered to obtain the filtered engineering parameters, including:

[0034] The engineering parameters of the first and second measuring points are filtered, including:

[0035]

[0036] Among them, Pz1, Pz2, Pz3, Pz4, and Pz5 represent the pressures at the 1st to 5th measuring points. The filtered pressure at the first measuring point. Vs1 represents the filtered pressure at the second measuring point; Vs2, Vs3, Vs4, and Vs5 represent the rotational speeds at measuring points 1 through 5. The filtered rotational speed at the first measurement point. The second measuring point represents the filtered rotational speed; PL1, PL2, PL3, PL4, and PL5 represent the pump displacement at measuring points 1 through 5. The filtered pump displacement at the first measuring point. The filtered pump displacement at the second measuring point;

[0037] The engineering parameters of the last two measuring points are filtered, including:

[0038]

[0039] Where N is the number of measurement points, Pz N-4 、Pz N-3 、Pz N-2 、Pz N-1 、Pz N For the pressure at the last 5 measuring points, The filtered pressure at the (N-1)th measuring point. Vs represents the filtered pressure at the Nth measuring point. N-4 Vs N-3 Vs N-2 Vs N-1 Vs N For the rotational speeds of the last 5 measuring points, The filtered rotational speed at the (N-1)th measuring point. The filtered rotational speed at the Nth measurement point; PL N-4 PL N-3 PL N-2 PL N-1 PL N For the pump displacement at the last 5 measuring points, The filtered pump displacement at the Nth measuring point. This represents the filtered pump displacement at the (N-1)th measuring point;

[0040] The engineering parameters of the remaining measuring points are filtered, including:

[0041]

[0042] Where k is the label of the measuring point, and 3≤k≤N-2. The filtered pressure at the k-th measuring point The filtered rotational speed at the k-th measurement point. Pz represents the filtered pump displacement at the k-th measuring point. k The pressure at the k-th measuring point, Vs k For the rotational speed at the k-th measuring point, PL k Let be the pump discharge rate at the k-th measuring point.

[0043] In one embodiment, the second grouting effect evaluation index parameter is defined by the following formula:

[0044]

[0045] Wherein, Q2 is the second grouting effect evaluation index parameter, f is the millimeter-level radar wave detection data detection map, f(i,j) represents the pixel value of pixel (i,j) in f, M is the horizontal number of pixels in f, T is the vertical number of pixels in f, and f(i,j|d,θ) represents the pixel value of pixel (i,j) in f that is d away from the center point of f and has an angle of θ.

[0046] In one embodiment, the third grouting effect evaluation index parameter is calculated using the following formula:

[0047]

[0048] Where Q3 is the third grouting effect evaluation index parameter, P is the distribution image of the surrounding medium of the borehole, M1 is the horizontal number of pixels in P, N1 is the vertical number of pixels in P, and P(i1,j1|d1,θ1) represents the pixel value of pixel (i1,j1) in P that is d1 away from the center point of P and has an angle of θ1.

[0049] In one embodiment, the comprehensive evaluation index parameters for long-distance drilling in step S7 are calculated using the following formula:

[0050] Q0 = aQ1 + bQ2 + cQ3

[0051] Wherein, Q0 is the comprehensive evaluation index parameter for long-distance drilling, Q1 is the first grouting effect evaluation index parameter, Q2 is the second grouting effect evaluation index parameter, Q3 is the third grouting effect evaluation index parameter, a, b, and c are the weights of Q1, Q2, and Q3 respectively, a+b=1, a>b, and c≥1.

[0052] Secondly, a system for evaluating the grouting effect in underground goaf areas of coal mines is provided, including:

[0053] The trajectory design module is used to design the trajectories of multiple long-distance boreholes based on goaf information;

[0054] The engineering parameter acquisition module is used to perform directional drilling of any long-distance borehole according to the trajectory and acquire engineering parameters during the directional drilling process, including drilling pressure, rotation speed and pump displacement.

[0055] The detection data acquisition module is used to detect long-distance boreholes using millimeter-level and meter-level radar wave detectors during directional drilling, and to obtain millimeter-level and meter-level radar wave detection data.

[0056] The first grouting effect evaluation index parameter determination module is used to filter, normalize and calculate standard scores of engineering parameters to obtain the first grouting effect evaluation index parameters.

[0057] The second grouting effect evaluation index parameter determination module is used to generate a millimeter-level radar wave detection data map of the borehole wall based on millimeter-level radar wave detection data, and calculate the second grouting effect evaluation index parameters based on the millimeter-level radar wave detection data map.

[0058] The third grouting effect evaluation index parameter determination module is used to perform full waveform inversion imaging on meter-level radar wave detection data to obtain the distribution image of the medium surrounding the borehole detection, and calculate the third grouting effect evaluation index parameters based on the distribution image of the medium surrounding the borehole detection.

[0059] The comprehensive evaluation index parameter determination module is used to accumulate the weights of the first grouting effect evaluation index parameter, the second grouting effect evaluation index parameter, and the third grouting effect evaluation index parameter to obtain the comprehensive evaluation index parameter for long-distance drilling.

[0060] The grouting effect level determination module is used to determine the grouting effect level of long-distance boreholes based on comprehensive evaluation index parameters and grouting effect grading standards.

[0061] The update module is used to update the grouting effect grading standard based on comprehensive evaluation index parameters and grouting effect level;

[0062] The judgment module is used to determine whether all long-distance boreholes have undergone directional drilling. If so, it obtains the grouting effect level of each long-distance borehole and enters the interpolation module; otherwise, it enters the engineering parameter acquisition module.

[0063] The interpolation module is used to determine the grouting effect level of unexplored areas in the goaf by using the Kriging interpolation method based on the grouting effect level of each long-distance borehole.

[0064] Compared with existing technologies, this application has the following advantages: Through directional drilling, this application can achieve long-distance detection and evaluation of the grouting effect of the goaf in a single operation, depending on the size of the goaf; the engineering parameters of directional drilling can evaluate the grouting solidification effect of the goaf; millimeter-wave radar detection methods can detect the state of the borehole wall, and the grouting effect can be intuitively analyzed based on the morphology of the borehole wall; meter-level radar detection methods can detect and evaluate the grouting effect within a certain range around the borehole; based on the detection of multiple boreholes in the goaf grouting area, this application ultimately achieves refined detection and evaluation of the entire goaf area. Furthermore, after the evaluation is completed, areas with poor grouting effects can be remedial grouting through these boreholes. Attached Figure Description

[0065] This application can be better understood by referring to the description given below in conjunction with the accompanying drawings, which, together with the detailed description below, are incorporated in and form part of this specification. In the drawings:

[0066] Figure 1 A flowchart illustrating the evaluation method for grouting effects in underground goaf areas of coal mines is shown.

[0067] Figure 2 A schematic diagram showing the distribution of long-distance boreholes is provided.

[0068] Figure 3 A schematic diagram of the trajectory of long-distance boreholes with a feather-like distribution is shown;

[0069] Figure 4 A schematic diagram of the trajectory of long-distance boreholes distributed in parallel is shown;

[0070] Figure 5 The image shows a detection map of millimeter-level radar wave detection data;

[0071] Figure 6 The distribution image of the surrounding medium detected by the borehole is shown;

[0072] Figure 7 The structural block diagram of the device for evaluating the grouting effect in underground goaf areas of coal mines is shown. Detailed Implementation

[0073] Exemplary embodiments of the present application will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of the actual embodiments are described in the specification. However, it should be understood that many embodiment-specific decisions can be made in the development of any such actual embodiment to achieve the developer’s specific objectives, and these decisions may vary as the embodiments differ.

[0074] It should also be noted that, in order to avoid obscuring this application with unnecessary details, only the device structure closely related to the solution according to this application is shown in the accompanying drawings, while other details that are not closely related to this application are omitted.

[0075] It should be understood that this application is not limited to the described embodiments by virtue of the following description with reference to the accompanying drawings. In this document, embodiments may be combined with each other, features may be substituted or borrowed between different embodiments, and one or more features may be omitted in one embodiment, where feasible.

[0076] This application provides a method for evaluating the grouting effect in underground goaf areas of coal mines. Figure 1 A flowchart illustrating the method for evaluating the grouting effect in underground goaf areas of coal mines is shown. (See attached diagram) Figure 1 The methods include:

[0077] Step S1: Design the trajectory of multiple long-distance boreholes based on the information of the goaf area.

[0078] Specifically, firstly, the number N of long-distance boreholes is determined based on the size of the goaf. B The following formula is used:

[0079]

[0080] Where V is the volume of the goaf, L is the length of the long-distance borehole, and R is the detection radius of the long-distance borehole;

[0081] Then, determine the distribution location of long-distance boreholes; the distribution location includes the center of the goaf, and the locations in the east, south, west, and north directions with the center of the goaf as a reference; Figure 2 A schematic diagram showing the distribution of long-distance boreholes is provided.

[0082] Then, the opening positions of multiple long-distance boreholes are located at the same opening point, and the multiple long-distance boreholes are distributed in a feather-like pattern; or the opening positions of multiple long-distance boreholes are different, and the multiple long-distance boreholes are distributed in parallel.

[0083] Here, for ease of construction, the borehole locations can be designed within the same drilling site, with the same starting point, but different borehole trajectories. The borehole location should be selected according to site requirements, ideally within the centerline area of ​​the goaf. The borehole trajectory design should be based on the shape and size of the goaf. For multiple long-distance boreholes with the same starting point, a feather-shaped distribution of the borehole segments can be designed, with parallel borehole trajectories after entering the goaf. Figure 3 A schematic diagram of the trajectory of long-distance boreholes with a feather-like distribution is shown. For boreholes with parallel opening positions, the borehole trajectory is designed as a parallel borehole. Figure 4A schematic diagram of the trajectory of long-distance boreholes distributed in parallel is shown.

[0084] Step S2: Based on the trajectory, perform directional drilling for any long-distance borehole and obtain the engineering parameters during the directional drilling process, including drilling pressure, rotation speed and pump discharge rate.

[0085] Here, directional drilling technology is used for drilling. Engineering parameters such as drilling pressure, rotation speed, and pump displacement are recorded during the directional drilling process. The construction process of directional drilling for long-distance boreholes is as follows: Based on the designed borehole trajectory, the preparatory work for directional drilling is carried out, the tool face angle of the instrument is determined, and then the long-distance borehole construction is carried out. During the construction process, the current borehole trajectory is measured through measurement while drilling, and the difference between the borehole trajectory and the designed trajectory is judged. If there is a deviation, the tool face angle of the instrument is adjusted. If there is no deviation, drilling continues until drilling is completed. During the drilling process, the drilling pressure Pz, rotation speed Vs, pump displacement PL, and other engineering parameters on the directional drilling rig dial are recorded with depth as the marker.

[0086] Step S3: During the directional drilling process, millimeter-level radar wave detectors and meter-level radar wave detectors are used to detect long-distance boreholes, and millimeter-level radar wave detection data and meter-level radar wave detection data are obtained.

[0087] Specifically, before directional drilling, the millimeter-level radar wave detector and the meter-level radar wave detector are turned on and synchronized with the controller at the borehole, and the storage working mode of the two instruments is activated.

[0088] Then, the depths of the millimeter-level and meter-level radar wave detectors in long-distance boreholes are marked, and the depth data is recorded in the form of timestamps.

[0089] Then, the data collected by the millimeter-level radar wave detector and the data collected by the meter-level radar wave detector are stored in the form of timestamps; the data collected by the millimeter-level radar wave detector is stored in the internal memory of the millimeter-level radar wave detector in the form of timestamps, and the data collected by the meter-level radar wave detector is stored in the internal memory of the meter-level radar wave detector in the form of timestamps.

[0090] Then, after directional drilling reaches the designed bottom of the hole, the depth marking on the borehole controller is stopped, and the millimeter-level radar wave detector and the meter-level radar wave detector are brought to the borehole opening.

[0091] Then, the measurement data from the millimeter-level radar wave detector is exported to the orifice controller. The data collected by the millimeter-level radar wave detector and the data collected by the meter-level radar wave detector are matched with the depth data according to the timestamp to obtain the millimeter-level radar wave detection data and meter-level radar wave detection data distributed along the depth.

[0092] Step S4 involves filtering, normalizing, and calculating standard scores for the engineering parameters to obtain the first grouting effect evaluation index parameters.

[0093] Step S5: Generate a millimeter-level radar wave detection data map of the borehole wall based on the millimeter-level radar wave detection data, and calculate the second grouting effect evaluation index parameters based on the millimeter-level radar wave detection data map.

[0094] Here, millimeter-level radar wave detection is used for high-precision imaging detection of the borehole wall. Preprocessing of the acquired millimeter-level radar wave detection data is required, including: (a) motion distortion compensation of the millimeter-wave radar data based on the motion during drilling; (b) point cloud framing processing of the millimeter-wave radar data; (c) transformation of the millimeter-wave detection data coordinate system into the drill pipe coordinate system; (d) filtering processing using the Kalman filter algorithm to remove noise; and (e) unfolding the filtered data along the borehole wall to generate a millimeter-level radar wave detection data map of the entire borehole wall. Figure 5 The image shows a detection map of millimeter-level radar wave detection data.

[0095] Step S6: Perform full waveform inversion imaging on the meter-level radar wave detection data to obtain the distribution image of the medium surrounding the borehole detection, and calculate the third grouting effect evaluation index parameters based on the distribution image of the medium surrounding the borehole detection.

[0096] Here, meter-level radar wave detection uses the borehole as the center and the detection range of the meter-level radar instrument as the radius to obtain the grouting effect around the borehole. Preprocessing of the meter-level radar wave detection data is required, including: data depth correction, gain processing, filtering, and normalization. One or two of the existing data processing methods can be selected based on the data quality characteristics. Full waveform inversion imaging is then performed on the preprocessed data to obtain an image of the distribution of the medium surrounding the borehole. Figure 6 The image shows the distribution of the surrounding medium detected by the borehole.

[0097] Step S7: Weight the first grouting effect evaluation index parameter, the second grouting effect evaluation index parameter, and the third grouting effect evaluation index parameter to obtain the comprehensive evaluation index parameter for long-distance drilling.

[0098] Specifically, the comprehensive evaluation index parameters for long-distance drilling can be expressed using the following formula:

[0099] Q0 = aQ1 + bQ2 + cQ3

[0100] Wherein, Q0 is the comprehensive evaluation index parameter for long-distance drilling, Q1 is the first grouting effect evaluation index parameter, Q2 is the second grouting effect evaluation index parameter, Q3 is the third grouting effect evaluation index parameter, a, b, and c are the weights of Q1, Q2, and Q3 respectively, a+b=1, a>b, and c≥1.

[0101] Step S8: Determine the grouting effect level of long-distance boreholes based on the comprehensive evaluation index parameters and the grouting effect grading standard.

[0102] Here, the grouting effect grading standard can be obtained in advance. Specifically, it can be achieved through numerical simulation and actual testing to obtain multiple sets of comprehensive evaluation index parameters and the grouting effect level of long-distance boreholes. The grouting effect grading standard is then manually determined, divided into five levels: I, II, III, IV, and V. Each level corresponds to a certain range of comprehensive evaluation index parameters. By determining the range of comprehensive evaluation index parameters currently obtained, the corresponding level can be determined. Among them, level V represents the best grouting effect in the goaf and requires no further treatment, while level I represents the worst grouting effect and requires further grouting treatment.

[0103] Step S9: Update the grouting effect grading standard based on the comprehensive evaluation index parameters and grouting effect level.

[0104] Here, the grouting effect grading standard is not fixed. After each acquisition of the comprehensive evaluation index parameters and grouting effect level corresponding to the borehole, the grouting effect grading standard can be updated. For example, if the currently acquired comprehensive evaluation index parameter does not fall within the range of any other comprehensive evaluation index parameter, the range of the closest comprehensive evaluation index parameter can be modified to ensure that the currently acquired comprehensive evaluation index parameter falls within the range.

[0105] Step S10: Determine whether all long-distance boreholes have been directionally drilled. If yes, obtain the grouting effect level of each long-distance borehole and proceed to step S11. If no, return to step S2.

[0106] Step S11: Based on the grouting effect level of each long-distance borehole, the Kriging interpolation method is used to determine the grouting effect level of the undetected area of ​​the goaf.

[0107] Here, considering that the number of long-distance boreholes cannot cover the entire goaf, the Kriging interpolation method is used to determine the grouting effect level of the unexplored areas of the goaf.

[0108] In this embodiment, directional drilling allows for long-distance detection and evaluation of the grouting effect in the goaf, tailored to its size. The engineering parameters of the directional drilling can evaluate the grouting solidification effect. Millimeter-wave radar detection can detect the borehole wall's condition, providing a direct analysis of the grouting effect. Meter-level radar detection can detect and evaluate the grouting effect within a certain range around the borehole. This embodiment, based on the detection of multiple boreholes in the goaf grouting area, ultimately achieves refined detection and evaluation of the entire goaf. Furthermore, after evaluation, the directional drilling boreholes can be used for remedial grouting in areas with poor grouting results.

[0109] In one embodiment, step S4 involves filtering, normalizing, and calculating standard scores for the engineering parameters to obtain the first grouting effect evaluation index parameters, including:

[0110] Step S41: Filter the engineering parameters for each measuring point to obtain the filtered engineering parameters; specifically, this can be achieved in the following way:

[0111] The engineering parameters of the first and second measuring points are filtered, including:

[0112]

[0113] Among them, Pz1, Pz2, Pz3, Pz4, and Pz5 represent the pressures at the 1st to 5th measuring points. The filtered pressure at the first measuring point. Vs1 represents the filtered pressure at the second measuring point; Vs2, Vs3, Vs4, and Vs5 represent the rotational speeds at measuring points 1 through 5. The filtered rotational speed at the first measurement point. The second measuring point represents the filtered rotational speed; PL1, PL2, PL3, PL4, and PL5 represent the pump displacement at measuring points 1 through 5. The filtered pump displacement at the first measuring point. The filtered pump displacement at the second measuring point;

[0114] The engineering parameters of the last two measuring points are filtered, including:

[0115]

[0116] Where N is the number of measurement points, Pz N-4 、Pz N-3 、Pz N-2 、Pz N-1 、Pz N For the pressure at the last 5 measuring points, The filtered pressure at the (N-1)th measuring point. Vs represents the filtered pressure at the Nth measuring point. N-4 Vs N-3 Vs N-2 Vs N-1 Vs N For the rotational speeds of the last 5 measuring points, The filtered rotational speed at the (N-1)th measuring point. The filtered rotational speed at the Nth measurement point; PL N-4 PL N-3 PL N-2 PL N-1 PL N For the pump displacement at the last 5 measuring points, The filtered pump displacement at the Nth measuring point. This represents the filtered pump displacement at the (N-1)th measuring point;

[0117] The engineering parameters of the remaining measuring points are filtered, including:

[0118]

[0119]

[0120] Where k is the label of the measuring point, and 3≤k≤N-2. The filtered pressure at the k-th measuring point The filtered rotational speed at the k-th measurement point. Pz represents the filtered pump displacement at the k-th measuring point. k The pressure at the k-th measuring point, Vs k For the rotational speed at the k-th measuring point, PL k Let be the pump discharge rate at the k-th measuring point.

[0121] Step S42: Normalize the filtered engineering parameters so that the data is distributed between [0,1], and obtain the normalized engineering parameters.

[0122] Specifically, the following formula is used:

[0123]

[0124] In the formula, n is the label of the nth measuring point, 1≤n≤N. These are the normalized pressure, speed, and pump displacement at the nth measuring point, respectively. These are the filtered pressure, rotational speed, and pump displacement at the nth measuring point, respectively. This represents the minimum pressure after filtering at all measuring points. This represents the maximum value of the filtered pressure at all measuring points. The minimum value of the rotational speed after filtering at all measuring points. The maximum value of the rotational speed after filtering at all measuring points. This represents the minimum pump displacement after filtering at all measuring points. This represents the maximum pump displacement after filtering at all measuring points.

[0125] Step S43: Calculate the standard score based on the normalized engineering parameters; the standard score includes the standard score of pressure, the standard score of rotational speed, and the standard score of pump displacement.

[0126] Specifically, first calculate the variances of pressure, speed, and pump displacement:

[0127]

[0128] Where, σ Pz σ Vs σ PL These are the variances of pressure, speed, and pump displacement, respectively. The mean pressure after normalization at all measuring points. The mean of the rotational speed after normalization across all measuring points. This is the mean of the pump displacement after normalization across all measuring points;

[0129] Then, the standard part Z of the pressure is calculated based on the variance of pressure, speed, and pump displacement. Pzn Standard division of rotational speed Z Vsn Standard division of pump displacement Z PLn The following formula is used:

[0130]

[0131] Step S44: Calculate the average of the standard scores for pressure, rotational speed, and pump displacement to obtain the grouting effect evaluation parameters for each measuring point; these can be expressed using the following formula:

[0132] Q1 n =(Z Pzn +Z Vsn +Z Vsn ) / 3

[0133] Among them, Q1 n The parameters are the grouting effect evaluation indicators for the nth measuring point.

[0134] Step S45: Calculate the mean value of the grouting effect evaluation index parameters for all measuring points to obtain the first grouting effect evaluation index parameter Q1. Here, Q1 can evaluate the grouting coagulation effect in the goaf. The smaller Q1 is, the better the grouting effect in the goaf; the larger Q1 is, the worse the grouting effect.

[0135] In one embodiment, the second grouting effect evaluation index parameter is defined by the following formula:

[0136]

[0137] Wherein, Q2 is the second grouting effect evaluation index parameter, f is the millimeter-level radar wave detection data detection map, f(i,j) represents the pixel value of pixel (i,j) in f, M is the horizontal number of pixels in f, T is the vertical number of pixels in f, and f(i,j|d,θ) represents the pixel value of pixel (i,j) in f that is d away from the center point of f and has an angle of θ.

[0138] Here, the second grouting effect evaluation index parameter reflects the complexity of the detection map of millimeter-level radar wave detection data. The complexity reflects the grouting effect. The worse the grouting effect, the higher the image complexity and the worse the image quality.

[0139] In one embodiment, the third grouting effect evaluation index parameter is calculated using the following formula:

[0140]

[0141] Where Q3 is the third grouting effect evaluation index parameter, P is the distribution image of the surrounding medium of the borehole, M1 is the horizontal number of pixels in P, N1 is the vertical number of pixels in P, and P(i1,j1|d1,θ1) represents the pixel value of pixel (i1,j1) in P that is d1 away from the center point of P and has an angle of θ1.

[0142] Here, the third grouting effect evaluation index parameter reflects the complexity of the data imaging map detected by meter-level radar waves. The complexity reflects the grouting effect within a certain range around the borehole. The worse the grouting effect, the greater the image change and the stronger the image heterogeneity. The better the grouting effect, the more uniform the texture between different regions of the image, the smaller the change, and the weaker the heterogeneity.

[0143] Based on the same inventive concept as the method for evaluating the grouting effect in underground goaf areas of coal mines, this embodiment also provides a corresponding device for evaluating the grouting effect in underground goaf areas of coal mines. Figure 7 The structural block diagram of a device for evaluating the grouting effect in underground goaf areas of coal mines is shown, including:

[0144] The trajectory design module 71 is used to design the trajectories of multiple long-distance boreholes based on goaf information;

[0145] The engineering parameter acquisition module 72 is used to perform directional drilling of any long-distance borehole according to the trajectory and acquire engineering parameters during the directional drilling process, including drilling pressure, rotation speed and pump displacement.

[0146] The detection data acquisition module 73 is used to detect long-distance boreholes using millimeter-level radar wave detectors and meter-level radar wave detectors during directional drilling, and to obtain millimeter-level radar wave detection data and meter-level radar wave detection data.

[0147] The first grouting effect evaluation index parameter determination module 74 is used to filter, normalize and calculate standard scores of engineering parameters to obtain the first grouting effect evaluation index parameters.

[0148] The second grouting effect evaluation index parameter determination module 75 is used to generate a millimeter-level radar wave detection data map of the borehole wall based on the millimeter-level radar wave detection data, and calculate the second grouting effect evaluation index parameters based on the millimeter-level radar wave detection data map.

[0149] The third grouting effect evaluation index parameter determination module 76 is used to perform full waveform inversion imaging on meter-level radar wave detection data to obtain the distribution image of the medium surrounding the borehole detection, and calculate the third grouting effect evaluation index parameters based on the distribution image of the medium surrounding the borehole detection.

[0150] The comprehensive evaluation index parameter determination module 77 is used to accumulate the weights of the first grouting effect evaluation index parameter, the second grouting effect evaluation index parameter, and the third grouting effect evaluation index parameter to obtain the comprehensive evaluation index parameter for long-distance drilling.

[0151] The grouting effect level determination module 78 is used to determine the grouting effect level of long-distance boreholes based on the comprehensive evaluation index parameters and the grouting effect grading standard.

[0152] Update module 79 is used to update the grouting effect grading standard based on comprehensive evaluation index parameters and grouting effect level;

[0153] The judgment module 710 is used to determine whether all long-distance boreholes have been directionally drilled. If so, the grouting effect level of each long-distance borehole is obtained and the process is entered into the interpolation module 711. If not, the process is entered into the engineering parameter acquisition module 72.

[0154] Interpolation module 711 is used to determine the grouting effect level of the unexplored area of ​​the goaf by using the Kriging interpolation method based on the grouting effect level of each long-distance borehole.

[0155] The coal mine underground goaf grouting effect evaluation device of this embodiment has the same inventive concept as the coal mine underground goaf grouting effect evaluation method described above. Therefore, the specific implementation of the device can be found in the embodiment section of the coal mine underground goaf grouting effect evaluation method described above, and its technical effect corresponds to the technical effect of the above method, so it will not be repeated here.

[0156] The above descriptions are merely various embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for evaluating the grouting effect in underground goaf areas of coal mines, characterized in that, include: Step S1: Design the trajectory of multiple long-distance boreholes based on the information of the goaf area; Step S2: Based on the trajectory, perform directional drilling of any long-distance borehole, and obtain engineering parameters during the directional drilling process, including drilling pressure, rotation speed and pump displacement. Step S3: During the directional drilling process, millimeter-level radar wave detectors and meter-level radar wave detectors are used to detect long-distance boreholes to obtain millimeter-level radar wave detection data and meter-level radar wave detection data. Step S4: Filter, normalize, and calculate the standard score of the engineering parameters to obtain the first grouting effect evaluation index parameters; Step S5: Generate a millimeter-level radar wave detection data map of the borehole wall based on the millimeter-level radar wave detection data, and calculate the second grouting effect evaluation index parameters based on the millimeter-level radar wave detection data map; Step S6: Perform full waveform inversion imaging on the meter-level radar wave detection data to obtain the distribution image of the medium surrounding the borehole detection, and calculate the third grouting effect evaluation index parameters based on the distribution image of the medium surrounding the borehole detection. Step S7: Weight the first grouting effect evaluation index parameter, the second grouting effect evaluation index parameter, and the third grouting effect evaluation index parameter to obtain the comprehensive evaluation index parameter of the long-distance borehole. Step S8: Determine the grouting effect level of long-distance boreholes based on the comprehensive evaluation index parameters and with reference to the grouting effect grading standard; Step S9: Update the grouting effect grading standard according to the comprehensive evaluation index parameters and the grouting effect level; Step S10: Determine whether all long-distance boreholes have been directionally drilled. If yes, obtain the grouting effect level of each long-distance borehole and proceed to step S11. If no, return to step S2. Step S11: Based on the grouting effect level of each long-distance borehole, the Kriging interpolation method is used to determine the grouting effect level of the undetected area of ​​the goaf.

2. The method as described in claim 1, characterized in that, Step S1: Design the trajectories of multiple long-distance boreholes based on the goaf information, including: The number of long-distance boreholes (N) is determined based on the size of the goaf. B The following formula is used: Where V is the volume of the goaf, L is the length of the long-distance borehole, and R is the detection radius of the long-distance borehole; Determine the distribution location of long-distance boreholes; the distribution location includes the center of the goaf, and the locations in the east, south, west, and north directions with the center of the goaf as a reference; The opening positions of the multiple long-distance boreholes are located at the same opening point, and the multiple long-distance boreholes are distributed in a feather-like pattern; or the opening positions of the multiple long-distance boreholes are different, and the multiple long-distance boreholes are distributed in parallel.

3. The method as described in claim 1, characterized in that, Step S3 involves using millimeter-level and meter-level radar wave detectors to detect long-distance boreholes, including: The depth of millimeter-level and meter-level radar wave detectors in long-distance boreholes is marked with dots, and the depth data is recorded in the form of timestamps. Data collected by millimeter-level and meter-level radar wave detectors are stored using timestamps. The data collected by the millimeter-level radar wave detector and the data collected by the meter-level radar wave detector are matched with the depth data according to the timestamp to obtain millimeter-level radar wave detection data and meter-level radar wave detection data distributed along the depth.

4. The method as described in claim 1, characterized in that, Step S4 involves filtering, normalizing, and calculating standard scores for the engineering parameters to obtain the first grouting effect evaluation index parameters, including: The engineering parameters at each measuring point are filtered to obtain the filtered engineering parameters. The filtered engineering parameters are normalized to obtain normalized engineering parameters; The standard score is calculated based on the normalized engineering parameters; the standard score includes the standard score of pressure, the standard score of rotational speed, and the standard score of pump displacement. The average values ​​of the standard scores of pressure, rotation speed, and pump displacement are calculated to obtain the grouting effect evaluation index parameters for each measuring point. The average value of the grouting effect evaluation index parameters of all measuring points is calculated to obtain the first grouting effect evaluation index parameter.

5. The method as described in claim 4, characterized in that, in, The engineering parameters at each measuring point are filtered to obtain the filtered engineering parameters, including: The engineering parameters of the first and second measuring points are filtered, including: Among them, Pz1, Pz2, Pz3, Pz4, and Pz5 represent the pressures at the 1st to 5th measuring points. The filtered pressure at the first measuring point. Vs1 represents the filtered pressure at the second measuring point; Vs2, Vs3, Vs4, and Vs5 represent the rotational speeds at measuring points 1 through 5. The filtered rotational speed at the first measurement point. The second measuring point represents the filtered rotational speed; PL1, PL2, PL3, PL4, and PL5 represent the pump displacement at measuring points 1 through 5. The filtered pump displacement at the first measuring point. The filtered pump displacement at the second measuring point; The engineering parameters of the last two measuring points are filtered, including: Where N is the number of measurement points, Pz N-4 、Pz N-3 、Pz N-2 、Pz N-1 、Pz N For the pressure at the last 5 measuring points, The filtered pressure at the (N-1)th measuring point. Vs represents the filtered pressure at the Nth measuring point. N-4 Vs N-3 Vs N-2 Vs N-1 Vs N For the rotational speeds of the last 5 measuring points, The filtered rotational speed at the (N-1)th measuring point. The filtered rotational speed at the Nth measurement point; PL N-4 PL N-3 PL N-2 PL N-1 PL N For the pump displacement at the last 5 measuring points, The filtered pump displacement at the Nth measuring point. This represents the filtered pump displacement at the (N-1)th measuring point; The engineering parameters of the remaining measuring points are filtered, including: Where k is the label of the measuring point, and 3≤k≤N-2. The filtered pressure at the k-th measuring point The filtered rotational speed at the k-th measurement point. Pz represents the filtered pump displacement at the k-th measuring point. k The pressure at the k-th measuring point, Vs k For the rotational speed at the k-th measuring point, PL k Let be the pump discharge rate at the k-th measuring point.

6. The method as described in claim 1, characterized in that, The second grouting effect evaluation index parameter adopts the following formula: Wherein, Q2 is the second grouting effect evaluation index parameter, f is the millimeter-level radar wave detection data detection map, f(i,j) represents the pixel value of pixel (i,j) in f, M is the horizontal number of pixels in f, T is the vertical number of pixels in f, and f(i,j|d,θ) represents the pixel value of pixel (i,j) in f that is d away from the center point of f and has an angle of θ.

7. The method as described in claim 1, characterized in that, The third grouting effect evaluation index parameter is defined by the following formula: Where Q3 is the third grouting effect evaluation index parameter, P is the distribution image of the surrounding medium of the borehole, M1 is the horizontal number of pixels in P, N1 is the vertical number of pixels in P, and P(i1,j1|d1,θ1) represents the pixel value of pixel (i1,j1) in P that is d1 away from the center point of P and has an angle of θ1.

8. The method as described in claim 1, characterized in that, In step S7, the comprehensive evaluation index parameters for the long-distance borehole are determined using the following formula: Q0 = aQ1 + bQ2 + cQ3 Wherein, Q0 is the comprehensive evaluation index parameter for long-distance drilling, Q1 is the first grouting effect evaluation index parameter, Q2 is the second grouting effect evaluation index parameter, Q3 is the third grouting effect evaluation index parameter, a, b, and c are the weights of Q1, Q2, and Q3 respectively, a+b=1, a>b, and c≥1.

9. A system for evaluating the grouting effect in underground goaf areas of coal mines, characterized in that, include: The trajectory design module is used to design the trajectories of multiple long-distance boreholes based on goaf information; The engineering parameter acquisition module is used to perform directional drilling of any long-distance borehole according to the trajectory, and to acquire engineering parameters during the directional drilling process, including drilling pressure, rotation speed and pump displacement. The detection data acquisition module is used to detect long-distance boreholes using millimeter-level and meter-level radar wave detectors during directional drilling, and to obtain millimeter-level and meter-level radar wave detection data. The first grouting effect evaluation index parameter determination module is used to filter, normalize and calculate the standard score of the engineering parameters to obtain the first grouting effect evaluation index parameters. The second grouting effect evaluation index parameter determination module is used to generate a millimeter-level radar wave detection data map of the borehole wall based on the millimeter-level radar wave detection data, and calculate the second grouting effect evaluation index parameters based on the millimeter-level radar wave detection data map. The third grouting effect evaluation index parameter determination module is used to perform full waveform inversion imaging on the meter-level radar wave detection data to obtain the distribution image of the medium surrounding the borehole detection, and calculate the third grouting effect evaluation index parameter based on the distribution image of the medium surrounding the borehole detection. The comprehensive evaluation index parameter determination module is used to perform weighted summation on the first grouting effect evaluation index parameter, the second grouting effect evaluation index parameter, and the third grouting effect evaluation index parameter to obtain the comprehensive evaluation index parameter of the long-distance borehole. The grouting effect level determination module is used to determine the grouting effect level of long-distance boreholes based on the comprehensive evaluation index parameters and the grouting effect grading standard. The update module is used to update the grouting effect grading standard according to the comprehensive evaluation index parameters and the grouting effect level; The judgment module is used to determine whether all long-distance boreholes have undergone directional drilling. If so, it obtains the grouting effect level of each long-distance borehole and enters the interpolation module; otherwise, it enters the engineering parameter acquisition module. The interpolation module is used to determine the grouting effect level of the undetected area of ​​the goaf by using the Kriging interpolation method based on the grouting effect level of each long-distance borehole.

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