Coal mine tunnel shield tunneling multi-frequency alternating current parallel advanced detection method and system

Abstract

The invention discloses a coal mine tunnel shield excavation-following multi-frequency alternating current parallel advanced detection method and system, and the method comprises the steps: arranging a three-direction data observation system in a tunnel excavation direction; collecting a three-direction potential difference amplitude value and a three-direction potential difference phase value for the arranged three-direction data observation system by adopting a multi-frequency pseudo-random galvanic couple source emission mode; the obtained three-direction potential difference amplitude value and the potential difference phase value are sent to professional software based on a Cole-Cole model for inversion, and a three-dimensional apparent resistivity image and a three-dimensional apparent charging rate image are obtained; according to the method, the problems that a traditional advanced detection method is insufficient in space positioning of a geologic body and detection is carried out while excavation under the tunnel shield condition are solved, and technical support is provided for tunnel shield excavation-while-excavation water disaster detection.

Description

Technical Field

[0001] The invention relates to the technical field of shield tunneling in coal mine tunnels, and in particular to a method and system for parallel advance detection of multi-frequency alternating current by shield tunneling in coal mine tunnels. Background Art

[0002] In the process of deep tunneling in coal mines, encountering unfavorable geological bodies such as hidden faults, collapse columns, caves, and fissure zones is a common challenge. Once these geological bodies are rich in water, they may cause serious water disasters such as water inrush, posing a serious threat to the safety and production efficiency of miners. Therefore, the implementation of advanced geological exploration has become a key link in the prevention and control of water hazards in coal mines. At present, technologies such as geological radar, transient electromagnetic method, DC resistivity method and dual-frequency induced polarization method are widely used in the detection of water-bearing properties of geological bodies ahead of tunneling. However, these methods have their own limitations: the geological radar method is affected by the rapid attenuation of high-frequency electromagnetic wave energy and the unevenness of the medium, the detection distance is short, and it is easily interfered by metal, resulting in a low signal-to-noise ratio; the transient electromagnetic method has a shallow detection blind area, and is seriously interfered by metal in the tunnel, which affects the actual detection effect; although the DC resistivity method and the dual-frequency induced polarization method are highly sensitive to the water-bearing properties of geological bodies and have a long detection distance, they can only observe the electrical parameters along the direction of the tunnel, and cannot accurately realize the spatial positioning of the geological body, resulting in insufficient precision in advanced detection.

[0003] In response to these technical problems, the invention patent with the patent publication number CN103645514A proposes a method and system for advanced detection of underground engineering with multi-isotropic source electrode array resistivity. This method mainly adopts the three-pole detection mode of the DC resistivity method, and measures the power supply current and potential difference by arranging power supply electrodes at the face and behind the tunnel, and measuring electrodes moving in the axial direction of the tunnel, and calculates the apparent resistivity value. However, this method has limited ability to capture parameters such as the occurrence, scale and resistivity of hidden geological anomalies, is insensitive to the front anomalies far away from the tunnel excavation working face, and has poor detection accuracy.

[0004] In order to further improve the detection accuracy, the invention patents with patent publication numbers CN111650652A, CN112505786A, and CN111856594A respectively proposed advance detection methods for tunnel three-directional apparent resistivity, apparent polarizability, and apparent polarizability. These methods arrange power supply points and measurement points on the survey line, observe the potential difference in three directions, calculate the three-directional electrical parameters, and obtain the three-dimensional electrical parameter image of the geological body in front of the tunnel excavation through inversion to determine the spatial position of the hidden disaster geological body and its water-bearing property.

[0005] However, the electrical parameters such as the three-directional apparent resistivity, apparent polarizability and video divergence mentioned above face some limitations in the data observation and inversion process: (1) The negative pole B of the power supply is placed at the rear of the tunnel excavation, which makes it easy for the current line to propagate along the rear of the tunnel, and the ability to capture water-rich anomalies at a long distance in front of the tunnel is weak, resulting in a short tunnel advance detection distance of the above method; (2) When observing the dispersion rate and polarizability, only the amplitude information of the electric field is observed, and the phase information is not observed, resulting in poor accuracy of the subsequent parameters such as the apparent polarizability and video divergence, and they are easily affected by the interference information around the tunnel; (3) The comprehensive interpretation method between the apparent resistivity, apparent polarizability and video divergence has not been clarified, and it is impossible to achieve intelligent identification of water-rich anomalies in tunnel excavation.

[0006] In addition, the invention patents with patent publication numbers CN105891890A and CN113156518A provide detection methods under shield tunneling conditions, but do not specify data observation information and interpretation methods, or only observe apparent resistivity, and still face the problem of resistivity multi-solution.

[0007] There are significant differences between shield tunneling in coal mine tunnels and traditional ground tunneling. The shield machine equipment occupies a large space, making it difficult to implement traditional construction methods; at the same time, the medium of coal mine tunnels is coal rock, which has low water content and poor conductivity. The three-dimensional induced polarization and focusing current devices used in ground tunnels are difficult to couple well with the medium in coal mine tunnels and cannot be applied. Therefore, with the acceleration of my country's coal mine intelligent construction and the promotion of shield tunneling construction in coal mine tunnels, it is urgent to develop a new method for advanced detection of water hazards in coal mine tunnels during shield tunneling. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a method for parallel advance detection of multi-frequency alternating current by shield tunneling in a coal mine.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0010] A method for parallel advance detection of multi-frequency alternating current by shield tunneling in coal mine tunnels, comprising:

[0011] In the direction of tunnel excavation, a three-directional data observation system is deployed;

[0012] For the deployed three-directional data observation system, a multi-frequency pseudo-random dipole source emission mode is adopted to collect the three-directional potential difference amplitude value and the three-directional potential difference phase value;

[0013] The obtained three-directional potential difference amplitude value and potential difference phase value are sent to the professional software based on the Cole-Cole model for inversion to obtain a three-dimensional apparent resistivity image and a three-dimensional apparent charge rate image;

[0014] Water-rich anomaly is determined based on the three-dimensional apparent resistivity image and the three-dimensional apparent charge rate image.

[0015] In one embodiment of the present invention, a three-directional data observation system is deployed, including:

[0016] S11, assuming that the tunnel excavation direction is the positive direction of the x-axis, the vertical upward direction is the positive direction of the y-axis, and the side of the tunnel is the positive direction of the z-axis, a spatial rectangular coordinate system is established, and an electrical survey line is arranged on the side of the tunnel along the negative direction of the x-axis, and the starting point of the electrical survey line is the intersection of the tunnel excavation working face and the electrical survey line;

[0017] S12, from the starting point of the electrical survey line, s control points are arranged in sequence at a distance d to the rear of the tunnel; three electrode holes are constructed at each control point using an anchor drill rig carried by a shield machine; after all electrode holes are constructed, each electrode hole is filled with a conductive medium using an injection device, and a set of power supply-measurement electrode groups are installed for the three electrode holes at each control point;

[0018] S13, the three electrode holes of each control point are numbered V1, V2 and V3 respectively, and the depth direction of each electrode hole is perpendicular to the side of the tunnel and constructed along the positive direction of the z-axis; wherein, the electrode hole V1 is located at the control point; the electrode hole V2 is located above the electrode hole V1, in the positive direction of the y-axis; the electrode hole V3 is located behind the electrode hole V1, in the negative direction of the x-axis;

[0019] S14, install a power supply-measurement electrode in the electrode hole V1 of each control point, and install a measurement electrode in the electrode hole V2 and the electrode hole V3 respectively; connect all control points through the electrical method line and connect them to the multi-frequency parallel electrical method instrument to form a complete power supply-measurement circuit.

[0020] In one embodiment of the present invention, the height of the electrical survey line from the bottom of the tunnel is consistent with the height of the anchor drill carried by the shield machine.

[0021] In one embodiment of the present invention, the first four control points A1 to A4 of the deployed three-directional data observation system are used as power supply points to transmit multi-frequency AC electric fields to the surrounding rocks in turn. When each control point transmits, the other control points receive three-directional data; the three-directional potential difference amplitude values ​​and three-directional potential difference phase values ​​are collected, including:

[0022] S21, the power supply-measurement electrode group installed in the control point includes a power supply-measurement electrode and two measurement electrodes, the electrode sheet No. 1 of the power supply-measurement electrode is numbered as P1, the electrode sheet No. 2 is numbered as P2, and the electrode sheets of the two measurement electrodes are numbered as P3 and P4 respectively; firstly, the electrode sheet No. 1 and the electrode sheet No. 2 in the power supply-measurement electrode in the control point A1 are used as the positive power supply electrode A and the negative power supply electrode B respectively to form a galvanic source emission mode, and 2 are used for each emission. 1 , 2 2 ……27 Multi-frequency pseudo-random signal synthesis emission, and record the power supply current I i The remaining control points receive the potential difference amplitude ΔU corresponding to all frequencies between P1P2, P3P2, and P4P2 in turn. x (f i ), ΔU y (f i ), ΔU z (f i ) and the potential difference phase value ΔF x (f i ), ΔF y (f i ), ΔF z (f i ), where f i Indicates different AC electric field frequencies; i indicates the control point number; the above process completes the three-directional multi-frequency AC electric field data of the remaining control points corresponding to the control point A1 power supply station;

[0023] S22, control point A2 supplies a multi-frequency pseudo-random AC electric field to the ground, and obtains the potential difference amplitude ΔU corresponding to all frequencies according to the data acquisition method in S21. x (f i ), ΔU y (f i ), ΔU z (f i ) and the potential difference phase value ΔF x (f i ), ΔF y (f i ), ΔF z (f i ); and so on, collect the three-directional multi-frequency AC electric field data of the first four control points in turn.

[0024] In one embodiment of the present invention, based on the Cole-Cole model inversion, a three-dimensional apparent resistivity image and a three-dimensional apparent charge rate image are obtained, using the following formula:

[0025]

[0026] Where ρ(iω) represents the resistivity when the angular frequency is ω, and ρ0 represents the resistivity when the frequency is zero. m It is expressed as charging rate, τ is expressed as time constant, c is expressed as frequency correlation coefficient, and i is expressed as imaginary unit; among them, potential difference amplitude and potential difference phase value are used to describe resistivity and charging rate; three-dimensional apparent resistivity image and three-dimensional apparent charging rate image are obtained by inversion of professional software using three-directional amplitude and phase data.

[0027] In one embodiment of the present invention, when inverting the apparent resistivity and apparent charge rate, the detection area is three-dimensionally gridded, and the apparent resistivity and apparent charge rate in each grid are calculated. The smooth constrained least squares inversion algorithm is used, and the apparent resistivity and apparent charge rate inversion objective function is:

[0028] S(m)=[dg(m)] T W d [dg(m)];

[0029] Where g is the theoretical AC electric field data matrix, d is the measured AC electric field data matrix, m is the resistivity matrix or charge rate matrix of the model, and W is d is the weight coefficient matrix; in order to make S(m) converge, the resistivity or charging rate m is modified multiple times during inversion, and the modified relationship is:

[0030] (J T W d J+λI)Δm=J T W d [dg(m)];

[0031] Where J is the Jacobi matrix, J T is the transposed matrix of J, λ is the damping factor, and I is the identity matrix.

[0032] In one embodiment of the present invention, during the forward construction of the shield machine, the shield machine anchor drill constructs a control point at a certain distance; the power supply-measurement electrode group and the multi-frequency parallel electrical instrument of all the control points at the rear are moved forward together, and the moving interval and the number of control points are related to the excavation progress of the day. In principle, control point A1 is the measurement point closest to the working face.

[0033] In one embodiment of the present invention, the water-rich anomaly is determined based on the three-dimensional apparent resistivity image and the three-dimensional apparent charge rate image, including:

[0034] S41, according to the test results of the physical parameters of the working area, set the apparent resistivity and apparent charge rate thresholds of the water-rich anomaly, extract the three-dimensional boundary coordinates of each low-resistance anomaly area in the three-dimensional apparent resistivity image, and number the anomaly areas as R1, R2, ..., R j ; Extract the three-dimensional boundary coordinates of the high charging rate abnormal area from the three-dimensional apparent charging rate image, and number the abnormal area as M1, M2, ..., M k ;

[0035] S42, the apparent resistivity abnormal area R1 and the apparent charge rate abnormal areas M1, M2, ..., M kSpatial correlation analysis is performed, and the area where the apparent resistivity anomaly area and the apparent charge rate anomaly area overlap in space is regarded as a high-probability water-rich anomaly; a single apparent resistivity anomaly or apparent charge rate anomaly is regarded as a low-probability water-rich anomaly; and so on, the apparent resistivity anomaly areas R2, ..., R j Respectively with the apparent charging rate abnormal area M1, M2, ..., M k Spatial correlation analysis is performed to obtain all abnormal water-rich areas in the work area, and they are ranked by probability to provide reference for the production department.

[0036] The present invention also provides a multi-frequency alternating current parallel advance detection system for a coal mine tunnel shield during excavation, which uses the above-mentioned multi-frequency alternating current parallel advance detection method for a coal mine tunnel shield during excavation, comprising:

[0037] The observation system module is used to deploy a three-directional data observation system in the tunnel excavation direction;

[0038] The potential and phase acquisition module is used to collect the three-directional potential difference amplitude value and the three-directional potential difference phase value of the deployed three-directional data observation system by adopting the multi-frequency pseudo-random electric dipole source emission mode;

[0039] The apparent resistivity and apparent charge rate module is used to send the acquired three-directional potential difference amplitude value and potential difference phase value to the professional software based on the Cole-Cole model for inversion to obtain a three-dimensional apparent resistivity image and a three-dimensional apparent charge rate image;

[0040] The joint determination module is used to jointly determine the water-rich anomaly based on the three-dimensional apparent resistivity image and the three-dimensional apparent charge rate image.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) Aiming at the special conditions of tunnel shield construction space, a method for advanced water hazard detection during tunneling is proposed, which is suitable for coal mine tunnel shield excavation conditions, meeting the actual needs of tunnel shield excavation and detection at this stage.

[0043] (2) The multi-frequency AC parallel advance detection method for shield tunneling in coal mines adopts a multi-frequency pseudo-random parallel AC emission and collection mode, which has high data collection efficiency, more comprehensive physical field information, and rich and more reliable physical property characteristic information, providing support for real-time and high-precision prediction of geological water bodies ahead of tunnel excavation.

[0044] (3) Taking advantage of the low resistance and high charge rate characteristics of water-rich anomalies, an intelligent identification method for geological water bodies was proposed through the joint inversion of the three-dimensional apparent resistivity and three-dimensional apparent charge rate ahead of the tunneling. This method overcomes the multi-solution problem faced by the traditional method of using only a single electrical parameter to explain water-rich anomalies, and greatly improves the accuracy of tunnel excavation detection.

[0045] (4) Solve the problems of insufficient spatial positioning of geological bodies by traditional advanced detection methods and simultaneous detection under tunnel shield conditions, and provide technical support for water hazard detection during tunnel shield excavation. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention is a flow chart of a method for parallel advance detection of multi-frequency alternating current by shield tunneling in a coal mine tunnel according to an embodiment of the present invention.

[0047] Figure 2 Schematic diagram of a power supply-measurement electrode group according to an embodiment of the present invention.

[0048] Figure 3 It is a three-dimensional schematic diagram of the deployment of a three-directional data observation system according to an embodiment of the present invention.

[0049] Figure 4 It is a schematic diagram of a two-dimensional profile extracted from three-dimensional apparent resistivity inversion data according to an embodiment of the present invention.

[0050] Figure 5 It is a schematic diagram of a two-dimensional profile extracted from three-dimensional apparent charge rate inversion data according to an embodiment of the present invention.

[0051] Figure 6 The present invention is a block diagram of a multi-frequency alternating current parallel advance detection system for shield tunneling in a coal mine tunnel according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] To facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention is further described in conjunction with the accompanying drawings.

[0053] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0054] See also Figure 1 As shown, the present invention provides a method for parallel advance detection of multi-frequency alternating current by shield tunneling in a coal mine tunnel, comprising:

[0055] S10: deploy a three-directional data observation system in the tunnel excavation direction.

[0056] In one embodiment of the present invention, a three-directional data observation system is deployed, including:

[0057] S11, assuming that the tunnel excavation direction is the positive direction of the x-axis, the vertical upward direction is the positive direction of the y-axis, and the side of the tunnel is the positive direction of the z-axis, establish a spatial rectangular coordinate system, and arrange an electrical survey line on the side of the tunnel along the negative direction of the x-axis. The starting point of the electrical survey line is the intersection of the tunnel excavation working face and the survey line, that is, the origin of the spatial rectangular coordinate system. Among them, the height of the electrical survey line from the bottom of the tunnel is consistent with the height of the anchor drill carried by the shield machine.

[0058] S12, from the starting point of the electrical survey line to the rear of the tunnel, that is, the negative direction of the x-axis, according to the distance d, generally d = 4m, s control points are arranged in sequence, such as Figure 3 A1, A2…, s≥20. At each control point, three electrode holes are constructed using an anchor drill rig carried by a shield machine, and the depth of each electrode hole is h=0.8m. After all electrode holes are constructed, an injection device is used to fill each electrode hole with a conductive medium, generally cannon mud, and a set of power supply-measurement electrode groups are installed for the three electrode holes at each control point.

[0059] S13, the three electrode holes of each control point are numbered V1, V2 and V3, and the depth of each electrode hole is h = 0.8m, and the hole depth direction is perpendicular to the side of the tunnel, that is, it is constructed along the positive direction of the z axis. Among them, the V1 hole mouth is located at the control point position, V2 is located above V1, that is, 0.5m in the positive direction of the y axis, and V3 is located behind V1, that is, 0.5m in the negative direction of the x axis.

[0060] S14, install a power supply-measurement electrode in the electrode hole V1 of each control point, and install a measurement electrode in the electrode hole V2 and the electrode hole V3. Among them, the power supply-measurement electrode is 80cm long and includes two electrode sheets, each of which is 5cm long. The center of electrode sheet No. 1 is 15cm away from the electrode tail end, the center of electrode sheet No. 2 is 10cm away from the electrode tip, and the center distance between the two electrode sheets is 50cm. The measurement electrode is 80cm long and includes one electrode sheet, which is 5cm long and 10cm away from the electrode tip. Figure 2 All control points are connected through the electrical method line and connected to the multi-frequency parallel electrical method instrument 5 to form a complete power supply-measurement circuit, such as Figure 3 As shown, number 1 in the figure represents the front of the tunnel excavation, number 2 represents the tunnel excavation working face, number 3 represents the tunnel, number 4 represents the electrical method line, number 6 represents the control point, number 7 represents the rear of the tunnel, and number 8 represents the front cutterhead section of the shield machine.

[0061] S20, for the deployed three-directional data observation system, a multi-frequency pseudo-random dipole source emission mode is adopted to collect the three-directional potential difference amplitude values ​​and the three-directional potential difference phase values.

[0062] In one embodiment of the present invention, after the three-directional data observation system is installed, three-directional multi-frequency AC electric field data collection is implemented. During the data collection process, the first four control points A1 to A4 are used as power supply points to transmit multi-frequency AC electric fields to the surrounding rock in turn. When each control point is transmitting, the other control points receive data in three directions. The specific data collection method is as follows:

[0063] S21, each power supply-measurement electrode group includes one power supply-measurement electrode and two measurement electrodes, the electrode sheet No. 1 of the power supply-measurement electrode is numbered P1, the electrode sheet No. 2 is numbered P2, and the electrode sheets of the two measurement electrodes are numbered P3 and P4. First, the electrode sheet No. 1 and the electrode sheet No. 2 of the power supply-measurement electrode of the control point A1 are used as the positive power supply electrode A and the negative power supply electrode B respectively to form a galvanic source emission mode, and each emission adopts 2 1 , 2 2 ……2 7 Multi-frequency pseudo-random signal synthesis emission, and record the power supply current I i The remaining control points receive the potential difference amplitude ΔU corresponding to all frequencies between P1P2, P3P2, and P4P2 in turn. x (f i ), ΔU y (f i ), ΔU z (f i ) and the potential difference phase value ΔF x (f i ), ΔF y (f i ), ΔF z (f i ), where f i represents different AC electric field frequencies; i represents the control point number; the above process completes the three-directional multi-frequency AC electric field data of the remaining control points corresponding to the control point A1 power supply station.

[0064] S22, control point A2 supplies a multi-frequency pseudo-random AC electric field to the ground, and obtains the potential difference amplitude ΔU corresponding to all frequencies according to the data acquisition method in S21. x (f i ), ΔU y (f i ), ΔU z (f i ) and the potential difference phase value ΔF x (f i ), ΔF y (f i ), ΔF z (f i ). Similarly, the three-directional multi-frequency AC electric field data of the first four control points are collected in sequence.

[0065] S30, sending the obtained three-directional potential difference amplitude values ​​and potential difference phase values ​​to professional software based on the Cole-Cole model for inversion to obtain a three-dimensional apparent resistivity image and a three-dimensional apparent charge rate image.

[0066] In one embodiment of the present invention, based on the Cole-Cole model inversion, a three-dimensional apparent resistivity image and a three-dimensional apparent charge rate image are obtained, using the following formula:

[0067]

[0068] Wherein, ρ(iω) represents the resistivity when the angular frequency is ω, ρ0 represents the resistivity when the frequency is zero, m represents the charging rate, τ represents the time constant, c represents the frequency correlation coefficient, and i represents the imaginary unit; among them, the potential difference amplitude and the potential difference phase value are used to describe the resistivity and charging rate.

[0069] The three-dimensional apparent resistivity image and the three-dimensional apparent charge rate image are obtained by inversion using the three-directional amplitude and phase data through professional software. Specifically, the professional software is, for example, tunnel audio electrical imaging software.

[0070] In this embodiment, inversion based on the Cole-Cole model is a conventional technical means in this field. The difference is that, currently, when observing the dispersion rate and polarizability, only the amplitude information of the electric field is observed, and the phase information is not observed. As a result, the parameters such as the apparent polarizability and the apparent dispersion rate obtained by inversion using the Cole-Cole model have poor accuracy and are easily affected by interference information around the tunnel. The present invention adds the observed phase information when using the Cole-Cole model for inversion.

[0071] In this embodiment, further, when the apparent resistivity and apparent charge rate are inverted, the detection area is three-dimensionally gridded, and the apparent resistivity and apparent charge rate in each grid are calculated. The smooth constrained least squares inversion algorithm is used, and the apparent resistivity and apparent charge rate inversion objective function is:

[0072] S(m)=[dg(m)] T W d [dg(m)];

[0073] Where g is the theoretical AC electric field data matrix, d is the measured AC electric field data matrix, m is the resistivity and charge rate matrix of the model, and W is d is the weight coefficient matrix; in order to make S(m) converge, the resistivity or charging rate m is modified multiple times during inversion, and the modified relationship is:

[0074] (J T W d J+λI)Δm=J T W d [dg(m)];

[0075] Where J is the Jacobi matrix, J T is the transposed matrix of J, λ is the damping factor, and I is the identity matrix.

[0076] In this embodiment, the above can be understood as the same method used to optimize the resistivity and the charging rate.

[0077] In one embodiment of the invention, during the forward construction of the shield machine, the shield machine anchor drill constructs a control point every 4 meters. All the power supply-measuring electrode groups, multi-frequency parallel electrical method instruments and other instruments and equipment at the rear control points are moved forward together, and the moving interval and the number of control points are related to the excavation progress of the day. In principle, the control point A1 is the closest measurement point to the working face.

[0078] S40, jointly determining water-rich anomaly based on the three-dimensional apparent resistivity image and the three-dimensional apparent charge rate image.

[0079] In one embodiment of the present invention, considering that rock resistivity is related to multiple factors such as rock mineral composition, structure, bedding, temperature, pressure, etc., a single apparent resistivity interpretation of water-rich anomaly has multiple solutions. To this end, the present invention uses apparent resistivity and apparent charge rate inversion images to jointly determine the water-rich anomaly area, specifically:

[0080] S41, according to the test results of the physical parameters of the working area, set the apparent resistivity and apparent charge rate thresholds of the water-rich anomaly, extract the three-dimensional boundary coordinates of each low-resistance anomaly area in the three-dimensional apparent resistivity image, and number the anomaly areas as R1, R2, ..., R j The three-dimensional boundary coordinates of the high charging rate abnormal area are extracted from the three-dimensional apparent charging rate image, and the abnormal areas are numbered as M1, M2, ..., M k Specifically, in this embodiment, the apparent resistivity threshold is 75Ω·m, and the apparent charging rate threshold is 1.7%.

[0081] S42, the apparent resistivity abnormal area R1 and the apparent charge rate abnormal areas M1, M2, ..., M k Spatial correlation analysis is performed, and the area where the apparent resistivity anomaly area and the apparent charge rate anomaly area overlap in space is regarded as a high-probability water-rich anomaly. A single apparent resistivity anomaly or apparent charge rate anomaly is regarded as a low-probability water-rich anomaly, and so on. j Respectively with the apparent charging rate abnormal area M1, M2, ..., M k Spatial correlation analysis is performed to obtain all abnormal water-rich areas in the work area, and they are ranked by probability to provide reference for the production department.

[0082] In one embodiment of the present invention, the above specific parameters are used as implementation cases. For ease of expression, two-dimensional profile data are extracted from the three-dimensional apparent resistivity and apparent charge rate data obtained by inverting the detection data of the tunnel on a certain day, and iso-mapped. The results show that low resistivity anomalies are present at 12 to 17 meters and 23 to 35 meters ahead of the excavation on the day of detection. Figure 4 , the high charging rate abnormality appeared at 26-32m ahead of the excavation. Figure 5 , using the combined determination method of the apparent resistivity anomaly and the apparent charge rate anomaly of the present invention, it is considered that the area 26 to 32 meters ahead of the tunnel excavation on that day is a high-probability water-rich abnormal area. The actual exposure results of the later tunnels show that the area 25 to 35 meters ahead of the tunnel excavation on the day of detection was uplifted by geological structural folds, and the rock strata were cracked and contained water.

[0083] The results of the implementation cases show that the scheme of the present invention has good applicability and reliability for advanced water hazard detection in tunnel shield tunneling, and can provide technical support for safe tunnel shield tunneling.

[0084] See also Figures 1 to 6 As shown, the present invention also provides a multi-frequency AC parallel advance detection system for shield tunnels in coal mines, which uses the multi-frequency AC parallel advance detection method for shield tunnels in coal mines, including:

[0085] The observation system module is used to deploy a three-directional data observation system in the direction of tunnel excavation.

[0086] The potential and phase acquisition module is used to collect the three-directional potential difference amplitude values ​​and three-directional potential difference phase values ​​for the deployed three-directional data observation system by adopting a multi-frequency pseudo-random electric dipole source emission mode.

[0087] The apparent resistivity and apparent charge rate modules are used to send the acquired three-directional potential difference amplitude values ​​and potential difference phase values ​​to the professional software based on the Cole-Cole model for inversion to obtain three-dimensional apparent resistivity images and three-dimensional apparent charge rate images.

[0088] The joint determination module is used to jointly determine the water-rich anomaly based on the three-dimensional apparent resistivity image and the three-dimensional apparent charge rate image.

[0089] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0090] The above-described embodiments merely represent implementation methods of the invention. The protection scope of the present invention is not limited to the above-described embodiments. For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for parallel advance detection of multi-frequency alternating current by shield tunneling in coal mine tunnels, characterized in that: include: In the direction of tunnel excavation, a three-directional data observation system is deployed; For the deployed three-directional data observation system, a multi-frequency pseudo-random dipole source emission mode is adopted to collect the three-directional potential difference amplitude value and the three-directional potential difference phase value; The obtained three-directional potential difference amplitude value and potential difference phase value are sent to the professional software based on the Cole-Cole model for inversion to obtain a three-dimensional apparent resistivity image and a three-dimensional apparent charge rate image; Water-rich anomaly is determined based on the three-dimensional apparent resistivity image and the three-dimensional apparent charge rate image.

2. The method for parallel advance detection of multi-frequency alternating current by shield tunneling in coal mine tunnels according to claim 1 is characterized in that: A three-directional data observation system is deployed, including: S11, assuming that the tunnel excavation direction is the positive direction of the x-axis, the vertical upward direction is the positive direction of the y-axis, and the side of the tunnel is the positive direction of the z-axis, a spatial rectangular coordinate system is established, and an electrical survey line is arranged on the side of the tunnel along the negative direction of the x-axis, and the starting point of the electrical survey line is the intersection of the tunnel excavation working face and the electrical survey line; S12, from the starting point of the electrical survey line, s control points are arranged in sequence at a distance d to the rear of the tunnel; three electrode holes are constructed at each control point using an anchor drill rig carried by a shield machine; after all electrode holes are constructed, each electrode hole is filled with a conductive medium using an injection device, and a set of power supply-measurement electrode groups are installed for the three electrode holes at each control point; S13, the three electrode holes of each control point are numbered V1, V2 and V3 respectively, and the depth direction of each electrode hole is perpendicular to the side of the tunnel and constructed along the positive direction of the z-axis; wherein, the electrode hole V1 is located at the control point; the electrode hole V2 is located above the electrode hole V1, in the positive direction of the y-axis; the electrode hole V3 is located behind the electrode hole V1, in the negative direction of the x-axis; S14, install a power supply-measurement electrode in the electrode hole V1 of each control point, and install a measurement electrode in the electrode hole V2 and the electrode hole V3 respectively; connect all control points through the electrical method line and connect them to the multi-frequency parallel electrical method instrument to form a complete power supply-measurement circuit.

3. The method for parallel advance detection of multi-frequency alternating current by shield tunneling in coal mine tunnels according to claim 2 is characterized in that: The height of the electrical survey line from the bottom of the tunnel is consistent with the height of the anchor drill rig carried on the shield machine.

4. The method for parallel advance detection of multi-frequency alternating current by shield tunneling in coal mine tunnels according to claim 1 is characterized in that: The first four control points A1~A4 of the deployed three-directional data observation system are used as power supply points to transmit multi-frequency AC electric fields to the surrounding rock in turn. When each control point is transmitting, the other control points receive three-directional data; the three-directional potential difference amplitude value and the three-directional potential difference phase value are collected, including: S21, the power supply-measurement electrode group installed in the control point includes a power supply-measurement electrode and two measurement electrodes, the electrode sheet No. 1 of the power supply-measurement electrode is numbered as P1, the electrode sheet No. 2 is numbered as P2, and the electrode sheets of the two measurement electrodes are numbered as P3 and P4 respectively; firstly, the electrode sheet No. 1 and the electrode sheet No. 2 in the power supply-measurement electrode in the control point A1 are used as the positive power supply electrode A and the negative power supply electrode B respectively to form a galvanic source emission mode, and 2 are used for each emission. 1 , 2 2 ……2 7 Multi-frequency pseudo-random signal synthesis emission, and record the power supply current I i The remaining control points receive the potential difference amplitude ΔU corresponding to all frequencies between P1P2, P3P2, and P4P2 in turn. x (f i ), ΔU y (f i ), ΔU z (f i ) and the potential difference phase value ΔF x (f i ), ΔF y (f i ), ΔF z (f i ), where f i Indicates different AC electric field frequencies; i indicates the control point number; the above process completes the three-directional multi-frequency AC electric field data of the remaining control points corresponding to the control point A1 power supply station; S22, control point A2 supplies a multi-frequency pseudo-random AC electric field to the ground, and obtains the potential difference amplitude ΔU corresponding to all frequencies according to the data acquisition method in S21. x (f i ), ΔU y (f i ), ΔU z (f i ) and the potential difference phase value ΔF x (f i ), ΔF y (f i ), ΔF z (f i ); and so on, collect the three-directional multi-frequency AC electric field data of the first four control points in turn.

5. The method for parallel advance detection of multi-frequency alternating current by shield tunneling in coal mine tunnels according to claim 1, characterized in that: Based on the Cole-Cole model inversion, the three-dimensional apparent resistivity image and the three-dimensional apparent charge rate image are obtained through the following formula: Wherein, ρ(iω) represents the resistivity when the angular frequency is ω, ρ0 represents the resistivity when the frequency is zero, m represents the charging rate, τ represents the time constant, c represents the frequency correlation coefficient, and i represents the imaginary unit; among them, the potential difference amplitude and the potential difference phase value are used to describe the resistivity and charging rate; the three-directional amplitude and phase data are used to obtain the three-dimensional apparent resistivity image and the three-dimensional apparent charging rate image through inversion by professional software.

6. The method for parallel advance detection of multi-frequency alternating current by shield tunneling in coal mine tunnels according to claim 5, characterized in that: When inverting the apparent resistivity or apparent charge rate, the detection area is three-dimensionally gridded, and the apparent resistivity and apparent charge rate in each grid are calculated. The smoothness-constrained least squares inversion algorithm is used, and the apparent resistivity and apparent charge rate inversion objective function is: S(m)=[d-g(m)] T W d [d-g(m)]; Where g is the theoretical AC electric field data matrix, d is the measured AC electric field data matrix, m is the model resistivity matrix or charge rate matrix, and W is d is the weight coefficient matrix; in order to make S(m) converge, the resistivity or charging rate m is modified multiple times during inversion, and the modified relationship is: (J T W d J+λI)Δm=J T W d [d-g(m)]; Where J is the Jacobi matrix, J T is the transposed matrix of J, λ is the damping factor, and I is the identity matrix.

7. The method for parallel advance detection of multi-frequency alternating current by shield tunneling in coal mine tunnels according to claim 4, characterized in that: During the forward construction of the shield machine, the anchor drill of the shield machine constructs a control point at a certain distance; the power supply-measurement electrode group and the multi-frequency parallel electrical instrument of all the control points at the rear are moved forward together. The moving interval and the number of control points are related to the excavation progress of the day. In principle, control point A1 is the measuring point closest to the working face.

8. The method for parallel advance detection of multi-frequency alternating current by shield tunneling in coal mine tunnels according to claim 1, characterized in that: The water-rich anomaly is determined based on the 3D apparent resistivity image and the 3D apparent charge rate image, including: S41, according to the test results of the physical parameters of the working area, set the apparent resistivity and apparent charge rate thresholds of the water-rich anomaly, extract the three-dimensional boundary coordinates of each low-resistance anomaly area in the three-dimensional apparent resistivity image, and number the anomaly areas as R1, R2, ..., R j ; Extract the three-dimensional boundary coordinates of the high charging rate abnormal area from the three-dimensional apparent charging rate image, and number the abnormal area as M1, M2, ..., M k ; S42, the apparent resistivity abnormal area R1 and the apparent charge rate abnormal areas M1, M2, ..., M k Spatial correlation analysis is performed, and the area where the apparent resistivity anomaly area and the apparent charge rate anomaly area overlap in space is regarded as a high-probability water-rich anomaly; a single apparent resistivity anomaly or apparent charge rate anomaly is regarded as a low-probability water-rich anomaly; and so on, the apparent resistivity anomaly areas R2, ..., R j Respectively with the apparent charging rate abnormal area M1, M2, ..., M k Spatial correlation analysis is performed to obtain all abnormal water-rich areas in the work area, and they are ranked by probability to provide reference for the production department.

9. A multi-frequency AC parallel advance detection system for shield tunneling in coal mines, characterized in that: The method for parallel advance detection of multi-frequency alternating current by shield tunneling in a coal mine tunnel as described in any one of claims 1 to 8 comprises: The observation system module is used to deploy a three-directional data observation system in the tunnel excavation direction; The potential and phase acquisition module is used to collect the three-directional potential difference amplitude value and the three-directional potential difference phase value of the deployed three-directional data observation system by adopting the multi-frequency pseudo-random electric dipole source emission mode; The apparent resistivity and apparent charge rate module is used to send the acquired three-directional potential difference amplitude value and potential difference phase value to the professional software based on the Cole-Cole model for inversion to obtain a three-dimensional apparent resistivity image and a three-dimensional apparent charge rate image; The joint determination module is used to jointly determine the water-rich anomaly based on the three-dimensional apparent resistivity image and the three-dimensional apparent charge rate image.

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