A synchronous monitoring method for seismic, electromagnetic and three-field during shield tunneling

Abstract

The present invention discloses a method for synchronous monitoring of seismic, electromagnetic, and electric fields during shield tunneling, which includes respectively arranging a seismic observation system during tunneling, an electric field observation system during tunneling, and an electromagnetic field observation system during tunneling in the shield construction tunnel; building an integrated seismic, electromagnetic, and electric field monitoring system, which includes a seismic data processing system during tunneling, an electric field data processing system during tunneling, and an electromagnetic field data processing system during tunneling; evaluating abnormal structures and water-richness in front of the tunnel to achieve synchronous multi-field monitoring of seismic, electromagnetic, and electric fields during shield tunneling. The present invention can simultaneously monitor three kinds of geophysical field signals of earthquake, electric field, and electromagnetic wave, and can achieve exploration while tunneling, improving the tunneling efficiency of the tunnel.

Description

Technical Field

[0001] The present invention belongs to the technical field of shield tunnel excavation technology, and specifically refers to a method for synchronous monitoring of seismic, electromagnetic fields during shield tunnel excavation. Background Art

[0002] Complex geological environments pose great challenges to the rapid excavation of shield tunnels. Transparency of the geological conditions ahead during excavation contributes to the safe construction of shield tunnels. To improve the excavation efficiency and ensure excavation safety, shield tunnels need to build a real-time advanced detection system for excavation and exploration with high intelligent equipment, high processing timeliness, and high credibility of geological models, which poses new requirements for advanced detection technologies. Tunnel advanced geological geophysical exploration technology is an effective means to understand the geological conditions in front of the tunnel face during tunnel construction, and to reduce or eliminate geological disasters during construction and ensure construction safety. Existing advanced geophysical exploration methods must suspend tunnel excavation operations during detection to avoid the impact of the construction environment on data collection, and there are problems such as heterogeneous equipment, scattered construction, sparse data, and impact on excavation. Therefore, how to achieve "excavation and exploration simultaneously" is an urgent problem to be solved in the current advanced detection of shield tunnels.

[0003] Tunnel advanced geological geophysical exploration technology is an effective means to understand the geological conditions in front of the tunnel face during tunnel construction, and to reduce or eliminate geological disasters during construction and ensure production safety. Common advanced geophysical exploration technologies include direct current method, transient electromagnetic method, and reflection seismic method, etc. However, in existing excavation geophysical exploration, usually only the signals of a single geophysical field are observed, and currently, during the detection of traditional advanced geophysical exploration methods, excavation operations need to be suspended to avoid the impact of the construction operation environment on detection data, which reduces the tunnel excavation efficiency and cannot achieve excavation and exploration simultaneously. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for synchronous monitoring of seismic, electromagnetic fields during shield tunnel excavation, which can simultaneously monitor the signals of three geophysical fields of earthquake, electric field, and electromagnetic wave, and can achieve excavation and exploration simultaneously, improving the tunnel excavation efficiency.

[0005] To achieve the above purpose, a method for synchronous monitoring of seismic, electromagnetic fields during shield tunnel excavation of the present invention includes the following steps:

[0006] Step 1: Respectively arrange an excavation seismic observation system, an excavation electric field observation system, and an excavation electromagnetic field observation system in the shield construction tunnel;

[0007] Step 2: Build an integrated seismic and electromagnetic monitoring system, which includes an excavation seismic data processing system, an excavation electric field data processing system, and an excavation electromagnetic field data processing system;

[0008] Step 3: The in-tunnel seismic data processing system uses the constructed seismic delay source advanced imaging method to convert and image the data;

[0009] Step 4: The in-tunnel electric field data processing system uses the electrical method for advanced detection;

[0010] Step 6: The in-tunnel electromagnetic field data processing system uses the time-frequency analysis method to process the electromagnetic data;

[0011] Step 6: Evaluate the abnormal structures and water-richness in front of the tunnel according to the processing results of Steps 3 to 5, and realize the synchronous monitoring of in-tunnel seismic, electromagnetic and multi-fields in front of the shield tunnel.

[0012] As a further solution of the present invention: The in-tunnel seismic observation system in Step 1 includes a plurality of geophones, which are respectively arranged in the linear area and the annular area. In the linear area, they are arranged along the segment on one side of the tunnel alignment. Starting from the connection between the front shield and the middle shield of the shield machine, a number of vertical geophones are arranged at equal intervals in the same height along the tunnel alignment towards the excavation rear. The Z direction of the geophone is perpendicular to the tunnel segment wall; the annular area is arranged at the starting point of the linear area, and a number of geophones are evenly arranged along the tunnel ring.

[0013] As a further solution of the present invention: The in-tunnel electric field observation system includes a plurality of wall-mounted electrodes, which are respectively arranged in the linear area and the annular area. In the linear area, a number of wall-mounted electrodes with equal intervals are arranged at the same height along the tunnel alignment towards the excavation rear, and a number of wall-mounted electrodes are evenly spaced in the annular area.

[0014] As a further solution of the present invention: The in-tunnel electromagnetic field observation system is to arrange a three-component electromagnetic coil at the connection between the front shield and the middle shield of the shield machine. The three-component electromagnetic coil includes the X direction, the Y direction, and the Z direction, where the X direction is consistent with the tunnel alignment, Y is perpendicular to X in the horizontal direction of the tunnel, and Z is the vertical direction of the tunnel.

[0015] As a further solution of the present invention: In Step 2, the seismic and electromagnetic integrated monitoring system further includes arranging a seismic and electromagnetic integrated monitoring base station in the central control room of the shield machine. The upper end of the seismic and electromagnetic integrated monitoring base station is connected to the ground switch and the server through the existing network of the shield machine. The lower end of the seismic and electromagnetic integrated monitoring base station accesses the cables of the in-tunnel seismic, electric, and magnetic fields to control the signal acquisition of the in-tunnel seismic observation system, the in-tunnel electric field observation system, and the in-tunnel electromagnetic field observation system. The ground server accesses the Internet to remotely transmit the in-tunnel seismic, electric, and magnetic field data to the data processing center in real time. The data processing center includes a multi-field processing system workstation and a monitoring platform.

[0016] As a further solution of the present invention: in step three, the seismic delay source advanced imaging method includes the following steps: performing pulse cross-correlation processing on the data, whereby a high-resolution pseudo-active source single-shot record can be obtained. ; and then using the full-scattering migration method to achieve imaging of the anomalies in front of the tunnel; wherein the pulse cross-correlation processing method is as follows:

[0017] S1: Calculate the autocorrelation of the single-channel seismic record , , representing the time delay;

[0018] S2: Construct the Toeplitz autocorrelation matrix , , where respectively represent the rows and columns of the matrix;

[0019] S3: Apply the Levinson recursion algorithm to solve the Yule-Walker equation: , where is the prediction coefficient vector, is the autocorrelation vector, and the deconvolution factor can be obtained through recursion;

[0020] S4: Pulse the signal ;

[0021] S5: Further calculate the autocorrelation of the pulsed signal , whereby the seismic single-channel record of the pseudo-active source can be obtained:

[0022] S6: Based on S1 to S5, process the remaining seismic channel signals in sequence, whereby a high-resolution seismic single-shot record of the pseudo-active source can be obtained;

[0023] The full-scattering migration method includes the following steps:

[0024] S1: Establish an advanced detection model (X, Y), where X is the tunnel driving direction, i.e., the horizontal direction, Y is the tunnel vertical direction, the origin is the face position, and calculate the travel time of the scattered wave propagation of a certain grid at the center position of the grid point : ;

[0025] In the formula t s is the travel time of the scattered wave from the source to the grid, t r is the travel time of the scattered wave from the grid to the geophone, x s and x r are the horizontal direction coordinates of the source and the geophone respectively, V is the stacking velocity;

[0026] S2: Calculate the scattered wave energy value in each grid, specifically by calculating the sum of squares of the values within a certain time window at different source-receiver pairs for each grid. t When the time is fixed.

[0027] S3: Based on S1 to S2 in the full scattered wave migration method, the advanced imaging result can be obtained, where the position corresponding to the grid with a large scattered wave energy value is the abnormal position.

[0028] As a further solution of the present invention: In step four, the electrical method advanced detection method includes the following steps: First, divide the area in front of the detection and perform grid meshing, extract the measured apparent resistivity data and eliminate the anomalies according to the limiting conditions of AM and MN, then perform weighted processing on the apparent resistivity measured under different MN at the same power supply point, then assign values to each unit grid, and finally calculate the apparent resistivity of the unit grid, thereby obtaining the resistivity distribution map in front of the tunnel excavation. Here, A is the power supply electrode, M and N are the measurement electrodes, and AM and MN respectively represent the potential differences between the two electrodes.

[0029] As a further solution of the present invention: In step five, the time-frequency analysis method includes the following steps: First, select the signals in the stable section during tunneling and calculate their multiple intrinsic mode functions, which are recorded as IMF1~IMFn from high frequency to low frequency in sequence; then extract the main frequency and amplitude in the IMF respectively, denoted as the main frequency f IMF1 , f IMF2 ,..., f IMFn and the amplitude A IMF1 , A IMF2 ,..., A IMFn energy, thereby obtaining the characteristic frequency and energy distribution of the electromagnetic signals during tunneling. Then, take the average of the multiple amplitude values corresponding to the main frequency of each IMF of the signals in different stable sections during tunneling, denoted as A1, A2,..., A n and use this as the threshold; when the amplitude of the characteristic frequency of the actually monitored signal exceeds 1.5 times the corresponding threshold, it indicates that the signal is abnormal at this characteristic frequency; when the number of abnormal characteristic frequencies reaches 1 / 2 of the total characteristic frequencies, it is considered that the electromagnetic field during tunneling is abnormal at this time and a warning is issued, thereby realizing the monitoring of the electromagnetic field during tunneling.

[0030] Compared with the prior art, the present invention utilizes a seismic monitoring system during tunneling, an electric field monitoring system during tunneling, and an electromagnetic field monitoring system during tunneling to collect seismic, electric field, and electromagnetic signal data during the tunneling process, and synchronously monitors the seismic, electric field, and electromagnetic field signals in real time through an integrated seismic, electric, and magnetic monitoring system; by designing a reasonable integrated seismic, electric, and magnetic monitoring system in the limited space of the construction tunnel, continuous dynamic monitoring of the geophysical field during tunneling can be achieved, providing a large amount of data for the detection of geological anomalies and water hazards in front of the shield tunnel, and improving the tunneling efficiency of the tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic flow chart of the method for synchronous monitoring of seismic, electric, and magnetic fields during tunneling of a shield tunnel according to the present invention.

[0032] Figure 2 is a schematic structural diagram of the arrangement position of the true electromagnetic field sensors of the shield tunnel according to the present invention.

[0033] Figure 3 is a structural framework diagram of the integrated seismic, electric, and magnetic monitoring system according to the present invention.

[0034] Figure 4 (a) is the original seismic record during tunneling monitored according to the present invention, Figure 4 (b) is the single-shot record of the pseudo-active source after pulse cross-correlation processing.

[0035] Figure 5 is the result of seismic imaging ahead during tunneling according to the present invention.

[0036] Figure 6 is the resistivity distribution map in front of the tunnel excavation according to the present invention.

[0037] Figure 7 is the processing result diagram of the electromagnetic signal during tunneling according to the present invention, where Figure 7 (a) is the frequency map of the original electromagnetic signal, Figure 7 (b) is the spectrum map of the original battery signal, Figure 7 (c) is the frequency map of IMF1 with a main frequency of 147 Hz and a peak value of 0.09 mV, Figure 7 (d) is the spectrum map of IMF2 with a main frequency of 633 Hz and a peak value of 0.06 mV, Figure 7 (e) is the frequency map of IMF3 with a main frequency of 244 Hz and a peak value of 0.04 mV, Figure 7 (f) is the spectrum map of IMF4 with a main frequency of 197 Hz and a peak value of 0.02 mV.

[0038] In the figure: 1. Cutter head, 2. Front shield, 3. Wall-mounted electrode, 4. Three-component electromagnetic coil, 5. Middle shield, 6. Rear shield, 7. Linear region, 8. Seismic geophone, 9. Annular region. DETAILED DESCRIPTION OF THE INVENTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings.

[0040] As Figure 1 shown, a method for synchronous monitoring of seismic, electromagnetic fields during shield tunneling includes the following steps:

[0041] Step 1: Arrange a seismic observation system during tunneling, an electric field observation system during tunneling, and an electromagnetic field observation system during tunneling in the shield construction tunnel respectively;

[0042] Step 2: Build an integrated seismic, electromagnetic and electric field monitoring system, which includes a seismic data processing system during tunneling, an electric field data processing system during tunneling, and an electromagnetic field data processing system during tunneling;

[0043] Step 3: The seismic data processing system during tunneling uses the constructed seismic delay source advanced imaging method to convert and image the data;

[0044] Step 4: The electric field data processing system during tunneling uses the electric method for advanced detection;

[0045] Step 5: The electromagnetic field data processing system during tunneling uses the time-frequency analysis method to process the electromagnetic data;

[0046] Step 6: Evaluate the abnormal structures (such as karst and faults) and water-richness in front of the tunnel according to the processing results of Steps 3 to 5, and realize the synchronous monitoring of multiple fields of seismic, electromagnetic and electric fields in front of the shield tunnel.

[0047] As Figure 2 shown, the shield machine successively includes a cutter head 1, a front shield 2, a middle shield 5, and a rear shield 6 from front to back. In Step 1, the seismic observation system during tunneling includes a plurality of geophones 8, and the geophones 8 are respectively arranged in a linear area 7 and an annular area 9. The linear area 7 is arranged along the segment on one side of the tunnel alignment. Starting from the connection between the front shield 2 and the middle shield 5 of the shield machine, 24 vertical geophones 8 with a spacing of 1 m are successively arranged at the same height along the tunnel alignment in the tunneling rear direction, and the Z direction of the geophone 8 is perpendicular to the tunnel segment wall; the annular area 9 is arranged at the starting point of the linear area 7, and eight geophones 8 are evenly arranged at intervals along the tunnel annulus, and are respectively located in eight directions of the upper, lower, left, right, upper left, lower left, upper right, and lower right of the tunnel annular area 9.

[0048] The observation system for the electromagnetic field during tunneling includes multiple wall-attached electrodes 3, which are respectively arranged in the linear region 7 and the annular region 9. Among them, the arrangement in the linear region 7 is the same as that of the seismic geophones in the linear region. Starting from the connection between the front shield 2 and the middle shield 5 of the shield machine, 24 wall-attached electrodes 3 with a spacing of 5 m are arranged at the same height along the tunnel direction towards the rear of tunneling; the annular region 9 is to arrange eight wall-attached electrodes at equal intervals along the tunnel ring at the starting point of the linear region 7, and they are respectively located in eight directions of the upper, lower, left, right, upper left, lower left, upper right, and lower right of the tunnel annular region 9.

[0049] The observation system for the electromagnetic field during tunneling is specifically to arrange a three-component electromagnetic coil 4 at the connection between the front shield 2 and the middle shield 5 of the shield machine. The three-component electromagnetic coil 4 includes the X direction, the Y direction, and the Z direction. Among them, the X direction is the same as the tunnel direction, the Y is perpendicular to the X in the horizontal direction of the tunnel, and the Z is the vertical direction of the tunnel.

[0050] In step two, as Figure 3 shown, the specific composition of the integrated seismic and electromagnetic monitoring system is to arrange an integrated seismic and electromagnetic monitoring base station in the central control room of the shield machine. The upper end of the integrated seismic and electromagnetic monitoring base station is connected to the ground switch and the server through the existing network of the shield machine. The lower end of the integrated seismic and electromagnetic monitoring base station accesses the cables of the seismic, electric, and magnetic fields during tunneling to control the signal acquisition of the observation system for the seismic field during tunneling, the observation system for the electric field during tunneling, and the observation system for the electromagnetic field during tunneling. The ground server accesses the Internet to remotely transmit the data of the seismic, electric, and magnetic fields during tunneling to the data processing center in real time. The data processing center includes a multi-field processing system workstation and a monitoring platform, and has functions such as data processing, result interpretation, and risk identification.

[0051] In step three, the seismic delay seismic source forward imaging method includes the following steps: performing pulse cross-correlation processing on the data, and thus a high-resolution quasi-active source single-shot record can be obtained , as Figure 4 shown; then using the full-scattering migration method to realize the imaging of the anomalies in front of the tunnel, as Figure 5 shown; among them, the pulse cross-correlation processing method is:

[0052] S1: Calculate the autocorrelation of the single-channel seismic record s ( t ) , represents the time delay;

[0053] S2: Construct a Toeplitz autocorrelation matrix , , where respectively represent the rows and columns of the matrix;

[0054] For example, the form of a third-order Toeplitz matrix is ;

[0055] S3: Solve the Yule - Walker equation using the Levinson recursion algorithm: , where is the prediction coefficient vector, is the autocorrelation vector, and the deconvolution factor can be obtained through recursion;

[0056] S4: Pulse the signal ;

[0057] S5: Further calculate the autocorrelation of the pulsed signal , from which the seismic single - trace record of the pseudo - active source can be obtained:

[0058] S6: Based on the above steps S1 to S5, process the remaining seismic - trace signals in sequence, and thus the high - resolution seismic single - shot record of the pseudo - active source can be obtained.

[0059] The full - scattering migration method includes the following steps:

[0060] S1: Establish a forward - detection model (X, Y), where X is the tunnel - driving direction, i.e., the horizontal direction, Y is the tunnel vertical direction, the origin is the face position, and the travel - time of the scattered wave propagation of a certain grid is calculated with the center position of the grid point ( x m ，y n ): ;

[0061] In the formula t s is the travel - time of the scattered wave from the source to the grid, t r is the travel - time of the scattered wave from the grid to the geophone, x s and x r are the horizontal - direction coordinates of the source and the geophone respectively, V is the stacking velocity;

[0062] S2: Calculate the scattered - wave energy value in each grid. Specifically, square - sum the values within a certain time window at the travel - time t of each grid under different source - geophone pairs;

[0063] S3: Based on the above S1 to S2, the forward - imaging result can be obtained, where the position corresponding to the grid with a large scattered - wave energy value is the abnormal position.

[0064] In Step 4, the electrical method for advanced detection includes the following steps: First, divide the area in front of the detection into grids and perform grid meshing. Extract the measured apparent resistivity data and eliminate anomalies according to the limiting conditions of AM and MN. Then, perform weighted processing (vertical stacking) on the apparent resistivity measured under different MNs at the same power supply point. Next, assign values to each unit grid (spatial offset processing). Finally, calculate the apparent resistivity of the unit grid, and thus obtain the resistivity distribution map in front of the tunnel excavation, as Figure 6 shown. Among them, A is the power supply electrode, M and N are the measurement electrodes, and AM and MN respectively represent the potential differences between the two electrodes.

[0065] In Step 5, the time-frequency analysis method includes the following steps: First, select the signals in the stable section during tunneling and calculate their multiple intrinsic modes, which are recorded as IMF1~IMFn from high frequency to low frequency in sequence; then, extract the main frequency and amplitude in the IMF respectively, denoted as the main frequency f IMF1 , f IMF2 …, f IMFn and the amplitude A IMF1 , A IMF2 …, A IMFn energy. Thus, the characteristic frequency and energy distribution of the electromagnetic signals during tunneling can be obtained. Then, take the average of the multiple amplitude values corresponding to the main frequency of each IMF of the signals in different stable sections during tunneling, and denote them as A1, A2,…, A n and use this as the threshold; when the amplitude of the characteristic frequency of the actually monitored signal exceeds 1.5 times the corresponding threshold, it indicates that the signal is abnormal at this characteristic frequency; when the number of abnormal characteristic frequencies reaches 1 / 2 of the total characteristic frequencies, it is considered that the electromagnetic field during tunneling is abnormal at this time and a warning is issued, thereby realizing the monitoring of the electromagnetic field during tunneling.

[0066] Method for obtaining intrinsic modes: Perform mode decomposition on the electromagnetic signals in the X, Y, and Z directions respectively E x ( t ), E y ( t ) and E z ( t ), and the specific steps are as follows:

[0067] S1: Calculate the local maximum and minimum values of the signal, and generate the upper and lower envelope lines through cubic spline interpolation e max ( t ) and e min (t );

[0068] S2: Calculate the average envelope line ;

[0069] S3: Update the signal and extract the candidate IMF: ;

[0070] S4: Repeat steps S1 - S3 until the standard deviation threshold of the IMF is satisfied;

[0071] S5: Separate the current IMF, denoted as , and at this time the residual term ;

[0072] S6: Repeat the above process for the residual term until the residual is negligible, and subsequent IMFs, denoted as IMF2 - IMFn, can be obtained.

[0073] As Figure 7 shown, Figure 7 (a) is the frequency diagram of the original electromagnetic signal, Figure 7 (b) is the spectrogram of the original battery signal, Figure 7 (c) is the frequency diagram of IMF1 with the main frequency of 147 Hz and the peak value of 0.09 mV, Figure 7 (d) is the spectrogram of IMF2 with the main frequency of 633 Hz and the peak value of 0.06 mV, Figure 7 (e) is the frequency diagram of IMF3 with the main frequency of 244 Hz and the peak value of 0.04 mV, Figure 7 (f) is the spectrogram of IMF4 with the main frequency of 197 Hz and the peak value of 0.02 mV.

[0074] The present invention can synchronously observe the seismic, electromagnetic, and geomagnetic three - field signals; by designing a reasonable integrated seismic - electromagnetic monitoring system in the limited space of the construction tunnel, continuous dynamic monitoring of the in - situ geophysical field during tunneling can be achieved, providing a large amount of data for the detection of geological anomalies and water hazards in front of the shield tunnel; the present invention forms a set of shield - tunnel in - situ seismic - electromagnetic multi - field synchronous observation methods integrating multi - field observation layout, signal real - time acquisition, and transmission, which will help to break through the problem of shield - tunnel advanced detection.

Claims

1. A synchronous monitoring method for seismic, electromagnetic and three - field during shield tunneling, characterized in that It includes the following steps: Step 1: Arrange a seismic observation system while tunneling, an electric field observation system while tunneling, and an electromagnetic field observation system while tunneling in the shield tunneling tunnel respectively; Step 2: Build an integrated seismic, electric and magnetic monitoring system, which includes a seismic data processing system while tunneling, an electric field data processing system while tunneling, and an electromagnetic field data processing system while tunneling; Step 3: The seismic data processing system while tunneling uses the constructed seismic delay source forward imaging method to convert and image the data; Step 4: The electric field data processing system while tunneling uses the electric method for forward detection; Step 5: The electromagnetic field data processing system while tunneling uses the time-frequency analysis method to process the electromagnetic data; Step 6: Evaluate the abnormal structure and water-richness in front of the tunnel according to the processing results of Steps 3 to 5, and realize the synchronous monitoring of multiple fields of seismic, electric and magnetic while tunneling in front of the shield tunnel; In the said Step 1, the seismic observation system while tunneling includes a plurality of geophones (8), and the geophones (8) are respectively arranged in the linear area (7) and the annular area (9). Among them, in the linear area (7), they are arranged along the segment lining on one side of the tunnel alignment. Starting from the connection between the front shield (2) and the middle shield (5) of the shield machine, a number of vertical geophones (8) are arranged at intervals in the same height along the tunnel alignment towards the tunneling rear. The Z direction of the geophone (8) is perpendicular to the tunnel segment wall; the annular area (9) is arranged at the starting point of the linear area (7), and a number of geophones (8) are arranged at equal intervals along the tunnel ring; The electric field observation system while tunneling includes a plurality of wall-mounted electrodes (3), and the wall-mounted electrodes (3) are respectively arranged in the linear area (7) and the annular area (9). On the linear area (7), a number of wall-mounted electrodes (3) with equal spacing are arranged at the same height along the tunnel alignment towards the tunneling rear, and a number of wall-mounted electrodes (3) are evenly distributed at intervals in the annular area (9); The electromagnetic field observation system while tunneling is to arrange a three-component electromagnetic coil (4) at the connection between the front shield (2) and the middle shield (5) of the shield machine. The three-component electromagnetic coil (4) includes the X direction, the Y direction, and the Z direction. Among them, the X direction is consistent with the tunnel alignment, Y is perpendicular to X in the horizontal direction of the tunnel, and Z is the vertical direction of the tunnel; In the said Step 2, the integrated seismic, electric and magnetic monitoring system further includes arranging an integrated seismic, electric and magnetic monitoring base station in the central operation room of the shield machine. The upper end of the integrated seismic, electric and magnetic monitoring base station is connected to the ground switch and server through the existing network of the shield machine. The lower end of the integrated seismic, electric and magnetic monitoring base station accesses the cables of the seismic, electric and magnetic fields while tunneling to control the signal acquisition of the seismic observation system while tunneling, the electric field observation system while tunneling, and the electromagnetic field observation system while tunneling. The ground server accesses the Internet to remotely transmit the seismic, electric and magnetic field data while tunneling to the data processing center in real time. The data processing center includes a multi-field processing system workstation and a monitoring platform.

2. The shield tunnel synchronous monitoring method of seismic, electromagnetic and electric fields during tunneling according to claim 1, wherein In Step 3, the seismic delay source forward imaging method includes the following steps: perform pulse cross-correlation processing on the data to obtain a high-resolution quasi-active source single-shot record s′(t); then use the full-scattering migration method to realize the imaging of the anomalies in front of the tunnel; among them, the pulse cross-correlation processing method is: S1: Calculate the autocorrelation r ss (τ) of the single-channel seismic record s(t): r ss (τ) = ∑ t s(t)·s(t + τ), where τ represents the time delay; S2: Construct the Toeplitz autocorrelation matrix R, where R i,j = r ss (|i - j|), where i and j represent the row and column of the matrix respectively; S3: Apply the Levinson recursion algorithm to solve the Yule-Walker equation: R·α = r, where α is the prediction coefficient vector and r is the autocorrelation vector, and obtain the deconvolution factor α through recursion i ; S4: Pulsed signal s′(t)=s(t)*a(t); S5: Further calculate the autocorrelation r ss ′(τ) = ∑ t s′(t)·s′(t + τ), thereby obtaining the seismic single-trace record of the pseudo-active source: S6: Based on S1 to S5, the remaining seismic trace signals are processed in sequence, thereby obtaining a high-resolution seismic single-shot record of a pseudo-active source; The total scatter migration method includes the following steps: S1: Establish an advanced detection model (X, Y), where X is the tunneling direction of the tunnel, i.e., the horizontal direction, Y is the vertical direction of the tunnel, the origin is the position of the tunnel face, and the travel time of the scattered wave propagation of a certain grid is calculated based on the central position (x m , y n ) of the grid point: where t s is the travel time of the scattered wave from the seismic source to the grid, and t r is the travel time of the scattered wave from the grid to the geophone, x s and x r are the horizontal coordinates of the seismic source and the geophone respectively, and V is the stacking velocity; S2: Calculate the scattered wave energy value in each grid, specifically, calculate the square sum of the values in a certain time window at time t of the propagation travel of each grid under different gun-detection pairs; S3: The advanced imaging result is obtained based on S1 to S2 in the full scattering migration method, where the position corresponding to the grid with a large scattered wave energy value is the abnormal position.

3. A synchronous monitoring method for seismic, electromagnetic and electric fields during shield tunneling according to claim 1, characterized in that, The electrical advance detection method in step 4 includes the following steps: first, the area and grid are divided into grids ahead of the detection, and the measured apparent resistivity data is extracted and anomalies are eliminated according to the restrictions of AM and MN. Then, the apparent resistivity measured under different MN at the same power supply point is weighted, and then each unit grid is assigned a value. Finally, the unit grid apparent resistivity is calculated, thereby obtaining a resistivity distribution map ahead of the tunnel excavation, wherein A is the power supply electrode, M and N are the measuring electrodes, and AM and MN represent the potential difference between the two electrodes respectively.

4. A synchronous monitoring method for seismic, electromagnetic, and electromagnetic fields during tunneling of a shield tunnel according to claim 1, characterized in that In Step 5, the time-frequency analysis method includes the following steps: First, select the signals in the stable section during tunneling, calculate its multiple intrinsic modes, and record them as IMF1 to IMFn from high frequency to low frequency in sequence; then extract the main frequency and amplitude in the IMF respectively, denoted as main frequency f IMF1 , f IMF2 , ……, f IMFn and amplitude A IMF1 , A IMF2 , ……, A IMFn energies, thereby obtaining the characteristic frequency and energy distribution of the electromagnetic signal during tunneling. Then, take the average of multiple amplitude values corresponding to the main frequency of each IMF of the signals in different stable sections during tunneling, and denote them as A1, A2, ……, A n respectively, and use this as the threshold; when the amplitude of the characteristic frequency of the actually monitored signal exceeds 1.5 times the corresponding threshold, it is indicated that the signal is abnormal at this characteristic frequency; when the number of abnormal characteristic frequencies reaches 1 / 2 of the total characteristic frequencies, it is considered that the electromagnetic field during tunneling is abnormal at this time and a warning is given, thereby realizing the monitoring of the electromagnetic field during tunneling.

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