A transient electromagnetic advance detection device and method for the direction of underground TBM tunneling.

Abstract

This invention discloses a transient electromagnetic advance detection device and method for the tunneling direction of a TBM in underground space. It uses a motor as the magnetic core to enhance the electromagnetic signal. Two transmitting coils and one receiving coil are deployed, with equal and opposite currents flowing through the two transmitting coils to form a source whose magnetic fields cancel each other out. A pure secondary field response signal is generated at the location of the receiving coil. This method can perform transient electromagnetic tunnel advance geological prediction detection of the tunneling direction of a TBM in underground space, and it has high detection accuracy with no blind spots within the detection range. Furthermore, regardless of whether the tunneling direction deviates during the detection process, this invention can always detect the direction ahead in the initial horizontal direction, thus ensuring the stability of the advance detection. In addition, the electromagnetic data is processed during the detection process to monitor whether the tunneling direction deviates in real time and determine the deviance angle information, thereby guiding the TBM to adjust its tunneling posture and ensuring tunneling efficiency.

Description

Technical Field

[0001] This invention relates to a transient electromagnetic advance detection device and method for the direction of underground space TBM tunneling, belonging to the field of geological exploration technology. Background Technology

[0002] Transient electromagnetic methods (TEM) for tunnel geological prediction typically employ magnetic and electrical sources. The traditional approach for electrical sources is the long offset transient electromagnetic method (LOTEM), which uses a grounded conductor several kilometers long to transmit current underground and observe the electromagnetic field response over an offset range greater than 3 to 6 times the detection depth. Compared to magnetic sources, this method is more complex to implement, and the electrical source is deployed along the tunnel's sidewalls, resulting in a very limited observation space for advanced detection. Furthermore, while the basic theory of the electrical source TEM is based on horizontal electric dipoles, in practice, the transmitting source is often a long grounded conductor. With the implementation of short offset observation methods, the size of the transmitting source cannot be ignored. However, due to site constraints, the transmitting source may not be able to be laid horizontally and vertically. This change in source morphology inevitably affects the response at the receiving point and ultimately impacts the accuracy of data interpretation.

[0003] Magnetic source TEM uses an ungrounded loop as the emission source to measure the magnetic field or its time derivative inside or outside the frame. Due to its advantages such as no need for grounding emission, strong high-resistance penetration capability, high coupling with anomalies, and convenient construction, various devices of magnetic source TEM have become the main working form of tunnel transient electromagnetic method for advanced geological prediction.

[0004] However, in actual tunnel construction, traditional transient electromagnetic (TEM) method advanced geological prediction devices generally use coaxial dipole devices. During TEM detection, the instrument's receiving coil is positioned 5m behind the tunnel face, and the prediction range is 20-100m in front of the receiving coil. Due to the inherent characteristics of the transient electromagnetic method, there is a detection blind zone from the receiving coil to 20m in front of it. Moreover, interference from metal equipment within the tunnel leads to discrepancies between TEM predictions and actual conditions. Furthermore, in tunnels constructed with tunnel boring machines (TBMs), the traditional transient electromagnetic device configuration is limited by the TBM machinery. This large machine occupies most of the construction space behind the tunnel face, making it impossible to deploy advanced detection survey lines, excitation devices, and receiving sensors on the tunnel face sidewalls. Additionally, the observation space for advanced geological prediction is very limited, making it difficult to establish an observation model sensitive to the geophysical response of adverse geological bodies in front of the tunnel face. In addition, TBMs generally tunnel in a horizontal straight line, but when tunneling through rock masses of different hardness, uneven stress can cause disturbances, which can lead to a deflection of the tunneling direction. Currently, the methods for monitoring deflection are relatively outdated, making it impossible to determine the deflection situation in a timely manner after it occurs, and ultimately failing to correct the deflection in time, thus reducing the efficiency of tunneling work.

[0005] Therefore, the research direction of this industry is to provide a method that can perform transient electromagnetic tunneling advance geological prediction and detection in the tunneling direction of underground TBMs with high detection accuracy, and at the same time monitor whether the tunneling direction of the TBMs deviates in real time, so as to make timely correction of the tunneling direction and ensure tunneling efficiency. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a transient electromagnetic advance detection device and method for the tunneling direction of underground TBMs. This device can perform transient electromagnetic tunnel advance geological prediction detection of the tunneling direction of underground TBMs, and has high detection accuracy. It can also monitor in real time whether the tunneling direction of the TBM deviates, so as to make timely correction of the tunneling direction and ensure the efficiency of tunneling.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a transient electromagnetic advance detection device for the tunneling direction of underground space TBM, comprising a transmitting coil, a receiving coil, a transient electromagnetic transceiver device, and a data processing terminal;

[0008] There are two transmitting coils, both wound around the outer circumference of the oil cylinder and spaced apart. The receiving coil is wound around the outer circumference of the motor located in the middle of the oil cylinder, so that the motor serves as the magnetic core of the receiving coil. The transient electromagnetic transceiver is connected to the transmitting coil and the receiving coil respectively, and is used to enable the electromagnetic signal excited by the transmitting coil to be amplified by the magnetic core and then pass through the blade of the cutter head, and to acquire the electromagnetic signal received by the receiving coil.

[0009] The data processing terminal and the transient electromagnetic transceiver are used to communicate wirelessly, and to receive electromagnetic data fed back by the transient electromagnetic transceiver, analyze and process it, and then determine whether there is an anomaly.

[0010] Furthermore, the two transmitting coils are parallel and coaxial with the same number of turns, and the two transmitting coils are respectively supplied with equal and opposite currents to form a transmitting source with mutually canceling magnetic fields, and generate a pure secondary field response signal at the position of the receiving coil.

[0011] Furthermore, the receiving coil and the transmitting coil are parallel and coaxial with each other, and the axes of the transmitting coil and the receiving coil are coaxial with the axis of the cutter head of the TBM machine.

[0012] Furthermore, the data processing terminal is a tablet computer.

[0013] The working method of the aforementioned transient electromagnetic advance detection device for the direction of underground TBM tunneling is as follows:

[0014] Step 1: TBM tunneling and transient electromagnetic advance detection: Install the transient electromagnetic advance detection device inside the TBM, then start the transient electromagnetic advance detection device to transmit and receive electromagnetic data, and transmit it to the data processing terminal.

[0015] Step 2, Anomaly Detection: After processing the feedback electromagnetic data, the data processing terminal determines the geological conditions within a certain range ahead. If no anomaly exists within this range, the TBM continues tunneling and proceeds to Step 3; if an anomaly exists, the TBM stops tunneling and the route is replanned or other measures are taken.

[0016] Step 3: Monitoring and Adjusting the TBM's Direction of Excavation: During the TBM's excavation process, disturbances can occur due to varying rock hardness, leading to a deflection of the excavation direction. The data processing terminal continuously receives electromagnetic data. Let the transient response at the center of the transmitting coil be B. z Its rate of change over time The specific formula is as follows:

[0017]

[0018] Where I is the transmitting current, ρ is the apparent resistivity of the half-space, a is the radius of the transmitting coil, μ is the current magnetic permeability of the geological surface, and T is time, calculated from the moment the current is turned off. It is an error function;

[0019] When the TBM is disturbed during tunneling, causing a deviation in the tunneling direction, it is assumed that the transmitting and receiving coils in the horizontal xy plane will deflect. The roll angle is η degrees, and the tilt angle of the transmitting and receiving coils in the vertical zy plane is η degrees; then the horizontal component of the transient electromagnetic response at the center of the transmitting coil is... After decomposition as follows:

[0020]

[0021] The above formula ensures that a certain component always faces the horizontal direction of the TBM's tunneling, thus achieving horizontal advance detection unaffected by tunneling direction deflection. Furthermore, the track map wirelessly transmitted by the transient electromagnetic transceiver to the data processing terminal is drawn in real time, thereby monitoring the tunneling direction deflection information in real time during tunneling and guiding the TBM to adjust its tunneling posture.

[0022] The principle behind this invention for achieving advanced detection is as follows: the propagation of the electromagnetic field conforms to Maxwell's equations, assuming divB = 0; for the interior of the magnetic core within the coil, the relationship between the magnetic field strength H, magnetic flux density B, and magnetization M is given by the following equation:

[0023]

[0024] We use the following relationship to calculate the divergence on both sides of formula (1):

[0025]

[0026] In formula (2), J is the magnetic polarization intensity; the magnetic polarization intensity represents the vector sum of the magnetic dipole moments within the magnetic material; the electromagnetic boundary condition forces B to be continuous in the direction perpendicular to the boundary, and the tangential component of H is continuous at the boundary between media with different electromagnetic properties; for isotropic ferromagnetic media, the following equation represents the magnetic flux in the receiver:

[0027] B R =μ0H R +D f J T +J T (3)

[0028] It can be seen from formula (3) that the magnetic induction intensity B of the receiving coil R It comes from three parts: the induced magnetic field of the receiving coil (μ0H) R ), demagnetizing field (D) f J T ) and the magnetic polarization field of the ferrite core (J T Therefore, based on the configuration of the mutual inductance analysis expression of the ferrite core transmitting and receiving coils, it can be concluded that when a cylindrical ferrite core is placed in the receiving coil, the core will be magnetized, and the magnetic flux through the receiving coil will increase, thus enhancing the electromagnetic signal.

[0029] Compared with existing technologies, this invention utilizes the above-mentioned principle, using a motor as a magnetic core to enhance the received electromagnetic signal. It also employs two transmitting coils and one receiving coil, with equal and opposite currents flowing through the two transmitting coils to create a source of mutually canceling magnetic fields. A pure secondary field response signal is generated at the location of the receiving coil. This method enables transient electromagnetic tunneling advance geological prediction and detection in underground space TBM excavation direction, offering high detection accuracy and eliminating blind spots within the detection range. Furthermore, regardless of whether the excavation direction deviates during detection, this invention consistently detects the initial horizontal direction ahead, ensuring the stability of the advance detection. Processing the electromagnetic data during detection allows for real-time monitoring of whether the excavation direction deviates and determination of the deviance angle, thereby guiding the TBM to adjust its excavation posture and ensuring excavation efficiency. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0031] Figure 2 This is a schematic diagram of the tunneling direction deflection monitoring in this invention.

[0032] In the diagram: 1-Hydraulic cylinder, 2-Motor, 3-Blade edge, 4-Transmitting coil, 5-Transient electromagnetic transceiver, 6-Receiving coil, 7-Blade disc. Detailed Implementation

[0033] The present invention will be further described below.

[0034] like Figure 1 As shown, a transient electromagnetic advance detection device for the direction of underground space TBM tunneling includes a transmitting coil 4, a receiving coil 6, a transient electromagnetic transceiver 5, and a data processing terminal.

[0035] Two transmitting coils 4 are wound around the outer circumference of the hydraulic cylinder 1 and are spaced apart. A receiving coil 6 is wound around the outer circumference of the motor 2 located in the middle of the hydraulic cylinder 1, with the motor 2 serving as the magnetic core of the receiving coil 6. A transient electromagnetic transceiver is connected to both the transmitting coils 4 and the receiving coil 6, used to generate an electromagnetic signal from the transmitting coils 4 that passes through the blade opening of the cutter head, and to acquire the electromagnetic signal received by the receiving coil 6 after the magnetic core has been amplified. The two transmitting coils 4 are parallel and coaxial with the same number of turns, and are supplied with equal and opposite currents to form a transmitting source with mutually canceling magnetic fields, generating a pure secondary field response signal at the location of the receiving coil 6. The receiving coil 6 is parallel and coaxial with the transmitting coils 4, and the axes of the transmitting coils 4 and the receiving coil 6 are coaxial with the axis of the TBM cutter head.

[0036] The data processing terminal and the transient electromagnetic transceiver 5 communicate wirelessly. The terminal receives electromagnetic data fed back by the transient electromagnetic transceiver 5, analyzes and processes it, and then determines whether there is an abnormality. The data processing terminal is a tablet computer.

[0037] The working method of the aforementioned transient electromagnetic advance detection device for the direction of underground TBM tunneling is as follows:

[0038] Step 1: TBM tunneling and transient electromagnetic advance detection: Install the transient electromagnetic advance detection device inside the TBM, then start the transient electromagnetic advance detection device to transmit and receive electromagnetic data, and transmit it to the data processing terminal.

[0039] Step 2, Anomaly Detection: After processing the feedback electromagnetic data, the data processing terminal determines the geological conditions within a certain range ahead. If no anomaly exists within this range, the TBM continues tunneling and proceeds to Step 3; if an anomaly exists, the TBM stops tunneling and the route is replanned or other measures are taken.

[0040] Step 3: Monitoring and Adjusting the Excavation Direction Deflection: During the TBM excavation process, disturbances can occur due to varying rock hardness, leading to deviations in the excavation direction. Figure 2 As shown, the data processing terminal continuously receives electromagnetic data. Let the transient response at the center of the transmitting coil be B. z Its rate of change over time The specific formula is as follows:

[0041]

[0042] Where I is the transmitting current, ρ is the apparent resistivity of the half-space, a is the radius of the transmitting coil, and μ is the magnetic permeability of the current geological conditions (approximately taken as 4π × 10⁻⁶). －7 H / m), T is time, calculated from the moment the current is turned off. It is an error function;

[0043] When the TBM is disturbed during tunneling, causing a deviation in the tunneling direction, it is assumed that the transmitting and receiving coils in the horizontal xy plane will deflect. The roll angle is η degrees, and the tilt angle of the transmitting and receiving coils in the vertical zy plane is η degrees; then the horizontal component of the transient electromagnetic response at the center of the transmitting coil is... After decomposition as follows:

[0044]

[0045] The above formula enables a certain component to always be oriented towards the horizontal direction of the TBM's tunneling, thereby achieving horizontal advance detection unaffected by tunneling direction deflection; and the track map wirelessly transmitted by the transient electromagnetic transceiver 5 to the data processing terminal is drawn in real time, thereby monitoring the tunneling direction deflection information in real time during the tunneling process, and thus guiding the TBM to adjust its tunneling posture.

[0046] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An underground space TBM tunneling direction transient electromagnetic advanced detection device, characterized in that, The application relates to a transient electromagnetic transmitting-receiving device and a data processing terminal. The two transmitting coils are wound on the outer circumferences of the oil cylinders and are apart from each other; the receiving coil is wound on the outer circumference of the motor at the middle part of the oil cylinder, so that the motor serves as the magnetic core of the receiving coil; the transient electromagnetic transmitting-receiving device is connected with the transmitting coil and the receiving coil respectively, and is used for exciting the transmitting coil to emit electromagnetic signals through the blade opening of the cutter head, and obtaining the electromagnetic signals received by the receiving coil after the magnetic core is enhanced; The data processing terminal and the transient electromagnetic transmitting-receiving device are in wireless communication, are used for receiving the electromagnetic data fed back by the transient electromagnetic transmitting-receiving device, and are used for judging whether an abnormal body exists after the electromagnetic data are analyzed and processed.

2. The underground space TBM heading direction transient electromagnetic advanced detection device according to claim 1, characterized in that, The two transmitting coils are parallel and coaxial and have the same number of turns, and the two transmitting coils are connected with equal and opposite currents to form the transmitting source whose magnetic fields are offset, and a pure secondary field response signal is generated at the position of the receiving coil.

3. The underground space TBM heading direction transient electromagnetic advanced detection device according to claim 1, characterized in that, The receiving coil and the transmitting coil are parallel and coaxial, and the axes of the transmitting coil and the receiving coil are coaxial with the axis of the cutter head of the TBM machine.

4. The underground space TBM heading direction transient electromagnetic advanced detection device according to claim 1, characterized in that, The data processing terminal is a tablet computer.

5. The working method of the underground space TBM tunneling direction transient electromagnetic advanced detection device according to any one of claims 1 to 4, characterized in that, The specific steps are as follows: Step one, TBM machine tunneling and transient electromagnetic advanced detection: the transient electromagnetic advanced detection device is installed in the TBM machine, then the transient electromagnetic advanced detection device is started to emit and receive electromagnetic data, and the electromagnetic data are transmitted to the data processing terminal; Step two, abnormal body judgment: the data processing terminal processes the fed back electromagnetic data, judges the geological conditions within a certain range in front, if no abnormal body exists within the range, the TBM machine continuously tunnels, and step three is entered; if an abnormal body exists, the TBM machine stops tunneling and the route is re-planned or other measures are taken; Step three, the direction of excavation deflection monitoring and adjustment posture: in the process of TBM excavation, the disturbance will occur due to the different hardness of rock mass, and then the direction of excavation will be deflected, the data processing terminal continuously receives electromagnetic data, and the transient response of the center of the transmitting coil is , the time rate of change is , and the specific formula is: ； ； where is the emitted current, is the apparent resistivity of the half-space, is the radius of the transmitter coil, is the magnetic permeability of the current geology, is time, reckoned from the current shut-off, is the error function; When the TBM machine is disturbed during tunneling, causing the tunneling direction to deviate, the roll angle of the transmitting coil and the receiving coil set in the horizontal xy plane is deviated by the degree of roll, and the inclination angle of the transmitting coil and the receiving coil set in the vertical zy plane is deviated by the degree of inclination; then the horizontal component of the transient electromagnetic response of the center of the transmitting coil by decomposition of the following formula: = ； The above formula can make a certain component always face the tunneling horizontal direction of the TBM machine, so that the horizontal advanced detection is not affected by the deflection of the tunneling direction; and the measurement track diagram transmitted to the data processing terminal by the transient electromagnetic transmitting-receiving device is real-time drawn, so that the deflection information of the tunneling direction is monitored in real time in the tunneling process, and the tunneling posture of the TBM machine is guided.

Images