Transient electromagnetic advance detection method for TBM tunnel

Abstract

The present invention discloses a TBM tunnel underground transient electromagnetic advance detection method, which belongs to the field of tunnel engineering technology, and includes the following steps: S1, laying a long wire on the ground and supplying a high-power step wave current to form a detection environment; S2, based on the pre-constructed detection environment, collecting multiple components of the electric field in various directions on the shield machine; S3, using time as the horizontal coordinate and the response amplitude as the vertical coordinate to draw the electric field multi-component response curve; S4, analyzing according to each component response curve to determine the detection result of the abnormal body. The present invention adopts the above-mentioned TBM tunnel underground transient electromagnetic advance detection method, which can realize the judgment of the geological conditions ahead of the tunnel, the judgment of the distance between the low-resistance abnormal body and the tunnel, the judgment of the direction of the low-resistance abnormal body relative to the tunnel, and then the judgment of the spatial position of the low-resistance abnormal body, and real-time detection of the water-bearing disaster body ahead of the excavation, which can improve the real-time performance of the advance prediction results.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel engineering, and in particular to a method for detecting transient electromagnetic advance detection during tunneling of a TBM tunnel. Background Art

[0002] Tunnel Boring Machine (TBM) has the technical advantages of safety and efficiency, and its application scale in major national tunnel projects such as highways, railways, high-speed railways and water conservancy projects has been steadily increasing. However, during the excavation process, once TBM encounters unexplored unfavorable geological bodies, it is very easy to cause disasters such as sudden water and mud, landslides and machine jams, and comprehensive forecasting technology means are needed for advanced detection.

[0003] The methods and technologies for advance detection of TBM tunnels have always been recognized as difficult problems at home and abroad. Currently, there are three main methods for advance detection of TBM tunnels: transient electromagnetic method, induced polarization method, and seismic method. The transient electromagnetic method mainly involves laying out electrical sources on the face to excite and measure the electric field, which can greatly reduce the electromagnetic interference caused by the TBM body. However, it requires the TBM to retreat 30-60cm before data collection can be carried out. Due to the difficulty of construction, it is difficult to achieve in TBM tunnels. It is also limited by the tunnel space. The maximum length of the electrical source cannot exceed the tunnel diameter, the emission magnetic moment is small, and the detection distance is very limited. Therefore, the current research and development of integrated excavation and automated real-time detection technology mounted on TBM has become the main development trend. The induced polarization method mainly includes AC induced polarization BEAM method and multi-isotropic source array induced polarization method. By installing additional electrodes on the TBM, the problem of narrow construction space and metal interference of shield machines is solved, and good application results have been achieved in many engineering practices. However, they are all geometric detection devices with an effective detection distance of no more than 30m. In addition, BEAM cannot detect geological structures with large inclination angles and cannot estimate water content. The array type requires the installation of multiple power supply electrodes, and data collection is relatively cumbersome. The seismic advance detection technology while excavating has a long detection distance and truly realizes integrated excavation and real-time detection. However, it is not sensitive to water bodies, making it difficult to estimate water content and unable to detect abnormal water bodies in front of the excavation working face.

[0004] In summary, the current TBM tunnel advance detection technology has its own application conditions and applicable scenarios. Long-distance detection and dynamic advance detection of water-containing disaster bodies during excavation cannot be achieved at the same time for the time being. Transient electromagnetic advance detection technology for medium and long distances during excavation is still in a blank stage. Summary of the invention

[0005] The purpose of the present invention is to provide a TBM tunnel underground transient electromagnetic advance detection method, which can realize the judgment of the geological conditions ahead of the tunnel, the judgment of the distance of the low-resistance anomaly from the tunnel, the judgment of the direction of the low-resistance anomaly relative to the tunnel, and then the judgment of the spatial position of the low-resistance anomaly, and real-time detection of the water-containing disaster body ahead of the excavation, which can improve the real-time performance of the advance forecast results.

[0006] To achieve the above object, the present invention provides a TBM tunnel transient electromagnetic advance detection method, comprising the following steps:

[0007] S1. Lay a long wire on the ground and supply a high-power step wave current to form a detection environment;

[0008] S2. Based on the pre-built detection environment, multiple components of the electric field in all directions are collected on the shield machine;

[0009] S3, plotting the electric field multi-component response curve with time as the horizontal axis and the response amplitude as the vertical axis;

[0010] S4. Analyze the response curves of each component to determine the detection results of the abnormal body.

[0011] Preferably, in step S1, according to the length of the tunnel in the constructed detection environment, a fixed long conductor serving the entire TBM tunnel construction cycle is laid on the surface as an electrical source.

[0012] Preferably, the length of the fixed long conductor is 500-1000m, and the fixed long conductor is 500-5000m away from the tunnel.

[0013] Preferably, in step S2, two measuring electrode circles 10 to 20 m apart are mounted in a surrounding manner on the shield behind the TBM cutterhead, and multiple components of the electric field in various directions are collected through the measuring electrode circles.

[0014] Preferably, there are a total of 8 measuring electrodes in the two measuring electrode circles, which are respectively mounted on the longitudinal axis and the horizontal axis passing through the center of the TBM; the 4 measuring electrodes of the first electrode circle close to the cutter head are defined as M1, M2, M3 and M4, respectively, and the 4 measuring electrodes of the second electrode circle are translated backward corresponding to the arrangement point of the first electrode circle, and are respectively defined as N1, N2, N3 and N4; multiple components of the electric field in various directions are collected by the 8 measuring electrodes; the 8 measuring electrodes form M1-N1, M2-N2, M3-N3 and M4-N4 electrode pairs parallel to the longitudinal axis, as well as M1-M3 and horizontal M2-M4 electrode pairs passing through the axis of the TBM and perpendicular, forming a total of 6 groups of measuring electrode pairs, and their response amplitude differences are calculated.

[0015] Preferably, in step S3, the electric field multi-component response curve is drawn with the basic parameter time of the transient electromagnetic field as the horizontal coordinate and the electric field response amplitude collected by the measuring electrode as the vertical coordinate, and the coordinates are double logarithmic coordinates; wherein, the electric field response amplitude takes an absolute value, and the electrode pair response amplitude is the absolute value of the response amplitude of one measuring electrode minus the absolute value of the response amplitude of the other measuring electrode, and then the absolute value is taken.

[0016] Preferably, in step S4, the presence of an abnormal body and the conductivity of the abnormal body are determined according to the response amplitude of the electrode pair or the curve jump point phenomenon; when a low-resistance abnormal body is detected, the distance of the abnormal body from the tunnel is inferred according to the change of the response amplitude of each electrode; according to the E of the second electrode ring x The component response or the E of the electrode pair passing through the TBM axis y By comparing the component responses, the relative position of the anomaly to the tunneling route of the shield machine can be inferred.

[0017] Therefore, the present invention adopts the above-mentioned TBM tunnel underground transient electromagnetic advance detection method, which can realize the judgment of the geological conditions ahead of the tunnel, the judgment of the distance of the low-resistance anomaly from the tunnel, the judgment of the direction of the low-resistance anomaly relative to the tunnel, and then the judgment of the spatial position of the low-resistance anomaly, and real-time detection of the water-containing disaster body ahead of the excavation, which can improve the real-time nature of the advance forecast results.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flow chart of the TBM tunnel transient electromagnetic advance detection method according to the present invention;

[0020] Figure 2 It is a schematic diagram of an observation device for the TBM tunnel underground transient electromagnetic advance detection method of the present invention;

[0021] Figure 3 is a schematic diagram of the detection environment constructed by the present invention;

[0022] Figure 4 This is the simulated accuracy diagram of a 1000m long wire source at different offset distances;

[0023] Figure 5 is the multi-component diffusion map of the electric field in the non-abnormal detection environment, where (a) is E x component, (b) is E y component, (c) is E z Quantity;

[0024] Figure 6is the multi-component diffusion diagram of the electric field in the high-resistance detection environment, where (a) is E x component, (b) is E y component, (c) is E z Quantity;

[0025] Figure 7 is the multi-component diffusion diagram of the electric field in the low-resistance body detection environment, where (a) is E x component, (b) is E y component, (c) is E z Quantity;

[0026] Figure 8 It is an abnormal body with different conductivity E x Influence diagram of component response, where (a) is the measurement electrode pair E with different conductivity M1-N1 x Response curve comparison diagram, (b) is the E of M1-M3 electrodes with different conductivity x Response curve comparison chart;

[0027] Fig. 9 It is an abnormal body with different conductivity E y Influence diagram of component response, where (a) is the measurement electrode E with different conductivity M2 y Response curve comparison diagram, (b) is the measurement of electrode pairs E with different conductivity M1-M3 y Response curve comparison chart;

[0028] Fig.10 The influence of abnormal bodies at different distances on the underground electric field components, where (a) is the measurement electrode E at different distances N2 x Response curve comparison diagram, (b) is the measurement of electrode pairs E at different distances M1-M3 y Response curve comparison chart;

[0029] Fig.11 is the low resistance anomaly at different horizontal positions to E x Influence diagram of component response, where (a) is the N2 and N4 measuring electrodes E when located on the left side of the excavation route x Comparison of response curves, (b) for N2 and N4 measuring electrodes E when located on the right side of the tunneling route x Response curve comparison chart;

[0030] Fig.12 is the low resistance anomaly at different horizontal positions to E y Influence diagram of component response, where (a) is the measurement electrode pair E at different horizontal positions M2-M4 y Response curve comparison diagram, (b) is the M2-M4 measurement electrode pair E when it is located on the left side of the tunneling route yResponse curve comparison diagram, (c) is the M2-M4 measurement electrode pair E when it is located on the right side of the tunneling route y Response curve comparison chart;

[0031] Fig.13 is the low-resistance anomaly at different vertical positions to E x Influence diagram of component response, where (a) is the N1 and N3 measuring electrodes E when located on the upper side of the excavation route x Comparison of response curves, (b) for N1 and N3 measuring electrodes E when located at the lower side of the tunneling route x Response curve comparison chart;

[0032] Fig.14 The low-resistance anomaly pair M1-M3 electrode pair E at different vertical positions y Influence plots of component responses. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0034] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0035] Example

[0036] like Figure 1 As shown, the present invention provides a method for TBM tunneling transient electromagnetic advance detection while excavating, comprising the following steps:

[0037] S1. Lay long wires on the ground and supply high-power step wave current to form a detection environment.

[0038] According to the length of the tunnel in the constructed detection environment, a fixed long wire is laid on the surface as an electrical source to serve the entire TBM tunnel construction cycle. The length of the fixed long wire is 500-1000m, and the fixed long wire is 500-5000m away from the tunnel.

[0039] S2. Based on the pre-built detection environment, multiple components of the electric field in all directions are collected on the shield machine.

[0040] like Figure 2 As shown in the figure, two measuring electrode circles with a distance of 10 to 20 meters are mounted in a surrounding manner at the shield behind the TBM cutterhead, and the multi-components of the electric field in all directions are collected through the measuring electrode circles. There are 8 measuring electrodes in the two measuring electrode circles, which are respectively mounted on the longitudinal axis and the horizontal axis passing through the center of the TBM; the 4 measuring electrodes of the first electrode circle close to the cutterhead are defined as M1, M2, M3 and M4, respectively, and the 4 measuring electrodes of the second electrode circle are translated backward corresponding to the arrangement point of the first electrode circle, and are defined as N1, N2, N3 and N4, respectively. The multi-components of the electric field in all directions are collected through the 8 measuring electrodes; the 8 measuring electrodes form the M1-N1, M2-N2, M3-N3 and M4-N4 electrode pairs parallel to the longitudinal axis, and the M1-M3 and horizontal M2-M4 electrode pairs passing through the axis of the TBM, forming a total of 6 groups of measuring electrode pairs, and their response amplitude differences are calculated.

[0041] S3. Draw the electric field multi-component response curve with time as the horizontal axis and the response amplitude as the vertical axis.

[0042] The electric field multi-component response curve is plotted with the basic parameter time of the transient electromagnetic field as the horizontal coordinate and the electric field response amplitude collected by the measuring electrode as the vertical coordinate, and the coordinates are double logarithmic coordinates; among which, the electric field response amplitude takes the absolute value, and the electrode pair response amplitude is the absolute value of the response amplitude of one measuring electrode minus the absolute value of the response amplitude of the other measuring electrode, and then the absolute value is taken.

[0043] S4. Analyze the response curves of each component to determine the detection results of the abnormal body.

[0044] The presence of an abnormal body and the conductivity of the abnormal body are determined based on the response amplitude of the electrode pair or the curve jump phenomenon; when a low-resistance abnormal body is detected, the distance of the abnormal body from the tunnel is inferred based on the change in the response amplitude of each electrode; based on the E of the second electrode circle x The component response or the E of the electrode pair passing through the TBM axis y By comparing the component responses, the relative position of the anomaly to the tunneling route of the shield machine can be inferred.

[0045] In order to verify the reliability of the TBM tunnel transient electromagnetic advance detection method adopted by the present invention, a three-dimensional finite difference numerical simulation is carried out, and the specific model parameters are as follows:

[0046] The YEE grid three-dimensional time-domain finite difference method is used to divide the space and time grids, and the non-uniform grids with dense center and sparse outside are selected for division. Figure 3The figure shows the pre-built detection environment. In the simulation, a tunnel model is designed. A plate-shaped anomaly is set in front of the tunnel, with a scale of 10m×40m×20m. The electrical source is spread 1000m along the Y direction on the ground. The tunnel section is designed as a square with a side length of 10m at 50m underground. A hexahedron with a length of 1m is designed as a cutter head at the head, with a resistivity of 1E-5Ω·m. It is located in the center of the calculation domain and the horizontal distance from the electrical source is 1000m. The whole tunnel is spread along the X-axis direction. The outer periphery of the tunnel is designed as a tunnel wall with a thickness of 1m and a resistivity of 1E3Ω·m. The internal cavity of the tunnel is often defined as a high-resistance body in geophysical models, with a cross-sectional side length of 4m and a resistivity of 1E5Ω·m. The receiving points are arranged at the center of the upper and lower tunnel walls and the left and right boundaries, and the distance between the two circles of receiving points is 20m.

[0047] The specific embodiments are described as follows (the following response curves are calculated and drawn after the data takes the absolute value):

[0048] (1) Calculate the theoretical values ​​of the electric field components at different offset distances from the surface and compare them with the numerical simulation results, such as Figure 4 As shown in the figure, the field response amplitude remains flat in the early stage, and the amplitude begins to decay when the electromagnetic field propagates to the measuring point. The results show that when a step wave current is supplied by a 1000m long wire source, the electric field component value at a distance of 1000m has a higher amplitude and a very low relative error, proving the reliability of the following numerical simulation.

[0049] (2) The position of the anomaly is set at 30m away from the tunnel, and its resistivity is changed to 100Ω·m, which is the same as the background resistivity, indicating no anomaly, high resistance 5000Ω·m and low resistance 1Ω·m. The multi-component diffusion diagram of the electric field in the XY section of the detection space is observed to analyze its underground electric field distribution characteristics. Figure 5 , Figure 6 , Figure 7 This is a comparison diagram of the diffusion field distribution characteristics of multiple components of the underground electric field at 0.88862ms. The red border represents the shield tunnel and the blue box represents the abnormal body.

[0050] The results show that the shield tunnel has a great influence on the x The influence of the diffusion field mainly comes from the metal cutterhead. The diffusion field forms two peak areas behind the cutterhead with opposite signs to the background field value. If there is an abnormal body in front of the tunnel, four peak areas will be formed around it, and the peak areas formed by abnormal bodies with different resistivities have opposite signs. When there is a low-resistance body, its influence on the diffusion field covers the abnormality of the shield tunnel itself, while the high-resistance body has little influence on the field distribution at the measuring point, and then it is concluded that E x The shield tunnel has a high sensitivity to low-resistance bodies. yThe influence of the diffusion field mainly comes from the tunnel cavity and the tunnel wall, and the diffusion field is distributed relatively stably around them. z The component has a large impact, the field distribution is chaotic, and it cannot be used as effective data, so only the horizontal component E is used. x and E y Analyze the data.

[0051] To determine the conductivity of the abnormal body: select the vertical measurement electrode pairs M1-N1 and M1-M3 to draw the E x Comparison of response curves, compared with the case without abnormal body (pure tunnel influence), Figure 8 (a) The high-resistance anomaly will cause a jump point to appear in the response curve of the M1-N1 measuring electrode pair; Figure 8 (b) The low-resistance anomaly will cause a jump point to appear in the response curve of the M1-M3 measuring electrode pair. x The jump point phenomenon of the response curve can quickly determine whether there is an unfavorable geological body in front of the tunnel that affects the progress of the tunnel, and can also distinguish the type of geological body.

[0052] like Fig. 9 As shown in (a), the M2 measuring electrode of the first electrode circle is selected to draw the E y The response curve shows that compared with the case without abnormal bodies (pure tunnel influence), low-resistance abnormal bodies will reduce the response amplitude of the entire period, while high-resistance abnormal bodies have a weaker effect on it, and only slightly accelerate the attenuation rate of the response amplitude in the late stage. Fig. 9 As shown in (b), the vertical measuring electrode pair M1-M3 is selected to draw the E y Comparison of response curves shows that compared with the case without abnormal bodies (pure tunnel influence), low-resistance abnormal bodies will reduce the difference, while high-resistance abnormal bodies have a weaker influence on it, and only slightly accelerate the attenuation rate of the response amplitude difference in the late stage. This verifies that the horizontal component response is more sensitive to the influence of low-resistance abnormal bodies.

[0053] (3) Determination of the distance between the low-resistance anomaly and the shield machine model: Change the distance between the low-resistance anomaly and the shield machine model to 30m, 40m, and 50m respectively. Fig.10 As shown in (a), the N2 measuring electrode of the second electrode circle was selected to draw the E x Response curve. Compared with the case without abnormal body (pure tunnel influence), the low-resistance abnormal body will increase the response amplitude of the whole period. The closer the shield machine model is to the low-resistance abnormal body, the greater the increase of the early response amplitude and the faster the decay rate in the late period. Fig.10 As shown in (b), the vertical electrode pair M1-M3 is selected to draw the E yComparison of response curves shows that the presence of low-resistance anomalies will reduce the difference compared to the absence of anomalies (pure tunnel influence). The closer the shield machine model is to the low-resistance anomaly, the greater the reduction in the response amplitude difference. Therefore, the distance between the low-resistance anomaly and the tunnel can be estimated by the change in the horizontal component amplitude.

[0054] (4) Determination of the horizontal position of the low-resistance anomaly: Change the horizontal distance of the low-resistance anomaly relative to the shield machine model, move 20 m along Y+ (left direction) and Y- (right direction), select the N2 and N4 measuring electrodes of the second electrode circle and draw the E x Response curve. Fig.11 As shown in (a), compared with the small difference between the two measuring electrodes when the low-resistance anomaly is in the middle of the shield machine model excavation route, when the low-resistance anomaly is located on the left side of the excavation route, the N4 electrode on the left will be far away from the peak area mentioned above, the amplitude will be greatly reduced, and a jump point phenomenon will occur, while the N2 electrode on the right will be close to the peak area, and the amplitude will be slightly increased. Fig.11 As shown in (b), when the low-resistance anomaly is located on the right side of the tunneling route, the response law is opposite.

[0055] The M2-M4 measuring electrode pair was selected to draw the E y Response curve. Fig.12 As shown in (a), compared with the small difference between the two electrodes when the low-resistance anomaly is in the middle of the shield machine model excavation route, when the horizontal position of the low-resistance anomaly changes, the response amplitude difference of M2-M4 will increase. y Response curve. Fig.12 As shown in (b), when the low-resistance anomaly is located on the left side of the tunneling route, the response amplitude of the right electrode M2 ​​increases and the response amplitude of the left electrode M4 decreases; Fig.12 As shown in (c), when the abnormal body is located on the right side of the excavation route, the response law is opposite. Therefore, the horizontal position of the low-resistance abnormal body can be determined by the difference in electrode amplitude on the left and right sides, where E x The difference in portion size is more pronounced.

[0056] (5) Determination of the vertical position of the low-resistance anomaly: The vertical distance of the low-resistance anomaly relative to the shield machine model was changed, and it was moved 20 m along the Z+ (downward direction) and Z- (upward direction) directions respectively. The N1 and N3 measuring electrodes of the second electrode circle were selected to draw the E x Response curve. Fig.13 As shown in (a), compared with the case where the low-resistance anomaly is in the middle of the tunneling route of the shield machine model, when the low-resistance anomaly is located on the upper side of the tunneling route, the N1 electrode response amplitude increases, the time point of the early jump point phenomenon is delayed, and the N3 measuring electrode early response amplitude increases. After the jump point phenomenon occurs, the amplitude remains basically unchanged. Fig.13As shown in (b), when the low-resistance anomaly is located at the lower side of the tunneling route, the response amplitudes of the N1 and N3 measuring electrodes both increase, and the time point when the early jump point phenomenon of the N1 electrode occurs is advanced.

[0057] The M1-M3 measuring electrode pair was selected to draw the response curve. Fig.14 As shown, compared with the case where the anomaly is in the middle of the shield machine model excavation route, when the low-resistance anomaly is located on the upper side of the excavation route, the low-resistance anomaly reduces the M1-M3 response amplitude difference; when the low-resistance anomaly is located on the lower side of the excavation route, the low-resistance anomaly increases the M1-M3 response amplitude difference.

[0058] Therefore, the vertical position of the low-resistance anomaly can be determined by the response amplitude changes and jump point phenomena of the upper and lower electrodes, or by the response amplitude difference of the vertically measured electrode pair M1-M3. Similarly, the response difference is more obvious.

[0059] Based on the discussion in (2), a preliminary judgment can be made on the geological conditions in front of the tunnel; combined with the discussion in (4) and (5), a preliminary judgment can be made on the direction of the low-resistance anomaly relative to the tunnel; combined with the discussion in (3), (4), and (5), a preliminary judgment can be made on the spatial position of the low-resistance anomaly.

[0060] The 8 measuring electrodes and 6 groups of measuring electrode pairs all have corresponding curve characteristics. When performing actual detection work, all response characteristics should be comprehensively considered to make an overall judgment.

[0061] Therefore, the present invention adopts the above-mentioned TBM tunnel underground transient electromagnetic advance detection method, which can realize the judgment of the geological conditions ahead of the tunnel, the judgment of the distance of the low-resistance anomaly from the tunnel, the judgment of the direction of the low-resistance anomaly relative to the tunnel, and then the judgment of the spatial position of the low-resistance anomaly, and real-time detection of the water-containing disaster body ahead of the excavation, which can improve the real-time nature of the advance forecast results.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for TBM tunneling transient electromagnetic advance detection, characterized in that: The following steps are involved: S1. Lay a long wire on the ground and supply a high-power step wave current to form a detection environment; S2. Based on the pre-built detection environment, multiple components of the electric field in all directions are collected on the shield machine; In step S2, two measuring electrode circles 10 to 20 meters apart are mounted in a surrounding manner on the shield behind the TBM cutterhead, and multiple components of the electric field in various directions are collected through the measuring electrode circles; There are 8 measuring electrodes in the two measuring electrode circles, which are respectively mounted on the longitudinal axis and the horizontal axis passing through the center of the TBM; the 4 measuring electrodes of the first electrode circle close to the cutterhead are defined as M1, M2, M3 and M4 respectively, and the 4 measuring electrodes of the second electrode circle are translated backward corresponding to the arrangement point of the first electrode circle, which are defined as N1, N2, N3 and N4 respectively. The 8 measuring electrodes are used to collect multiple components of the electric field in various directions; the 8 measuring electrodes are composed of M1-N1, M2-N2, M3-N3 and M4-N4 electrode pairs parallel to the longitudinal axis, and M1-M3 and M2-M4 electrode pairs perpendicular to the axis of the TBM and horizontal, forming a total of 6 groups of measuring electrode pairs, and their response amplitude differences are calculated; S3, plotting the electric field multi-component response curve with time as the horizontal axis and the response amplitude as the vertical axis; In step S3, the electric field multi-component response curve is drawn with the basic parameter time of the transient electromagnetic field as the horizontal coordinate and the electric field response amplitude collected by the measuring electrode as the vertical coordinate, and the coordinates are double logarithmic coordinates; wherein the electric field response amplitude is taken as an absolute value, and the electrode pair response amplitude is the absolute value of the response amplitude of one measuring electrode minus the absolute value of the response amplitude of the other measuring electrode, and then the absolute value is taken; S4. Analyze the response curves of each component to determine the detection result of the abnormal body; In step S4, the presence of an abnormal body and the conductivity of the abnormal body are determined based on the response amplitude of the electrode pair or the curve jump point phenomenon; when a low-resistance abnormal body is detected, the distance of the abnormal body from the tunnel is inferred based on the change in the response amplitude of each electrode; based on the E x The component response or the E of the electrode pair passing through the TBM axis y By comparing the component responses, the relative position of the anomaly to the tunneling route of the shield machine can be inferred.

2. The method for TBM tunneling transient electromagnetic advance detection according to claim 1 is characterized in that: In step S1, according to the length of the tunnel in the constructed detection environment, a fixed long conductor serving the entire TBM tunnel construction cycle is laid on the surface as an electrical source.

3. The method for TBM tunneling transient electromagnetic advance detection according to claim 1 is characterized in that: The length of the fixed long conductor is 500-1000m, and the distance between the fixed long conductor and the tunnel is 500-5000m.

Images