Tunnel geological detection system and method, storage medium, and program product

Abstract

The present disclosure provides a tunnel geological detection system and method, storage medium, and computer program product, the system therein comprising: a current source, a transmitting electrode, a shielding electrode, a return electrode, a voltage difference signal measurement module, and a collection control module, the collection control module controlling the current source to output a current to the transmitting electrode in a first operation mode and controlling the current source to output a current to the shielding electrode in a second operation mode according to an electric field synthesis ratio parameter, such that the transmitting electrode emits a current to a target formation under the action of electric field superposition to determine an apparent resistivity corresponding to the target formation, wherein when the transmitting electrode emits the current to the target formation, voltage difference information is less than a voltage difference threshold.

Description

Tunnel geological exploration systems, methods, storage media, and program products

[0001] Cross-reference to related applications

[0002] This disclosure is based on and claims priority to CN application No. 202411681517.1 filed on November 22, 2024, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This application relates to the field of tunnel geological prediction technology, and in particular to a tunnel geological detection system, method, storage medium, and computer program product. Background Technology

[0004] Bore-Tunneling Electrical Ahead Monitoring (BEAM) is a technique that uses electrical methods for advanced geological prediction of tunnels. In BEAM, a shielding current is emitted into a shielded electrode and a measuring current is emitted into a measuring electrode. This measuring current is focused into the rock mass to be probed. By analyzing changes in the rock mass's resistivity parameters, the integrity and water content of the rock mass ahead of the tunnel face can be predicted. Summary of the Invention

[0005] According to a first aspect of this disclosure, a tunnel geological detection system is provided, comprising: a current source, a transmitting electrode, a shielding electrode, a return electrode, a differential pressure signal measurement module, and an acquisition and control module; a detection circuit corresponding to a first operating mode includes the transmitting electrode and the return electrode, and a detection circuit corresponding to a second operating mode includes the shielding electrode and the return electrode; the differential pressure signal measurement module is used to detect the voltage difference between the transmitting electrode and the shielding electrode, and determine voltage differential information based on the voltage difference; the acquisition and control module is used to determine an electric field synthesis ratio parameter; based on the electric field synthesis ratio parameter, the current source is controlled to output current to the transmitting electrode in the first operating mode, and the current source is controlled to output current to the shielding electrode in the second operating mode, so that the transmitting electrode emits current to the target formation under the superposition of electric fields, thereby determining the apparent resistivity corresponding to the target formation; wherein, when the transmitting electrode emits current to the target formation, the voltage differential information is less than a differential pressure threshold.

[0006] In some embodiments, the acquisition and control module is configured to acquire first voltage difference information determined by the voltage difference signal measurement module when controlling the current source to output current to the transmitting electrode in the first operating mode; acquire second voltage difference information determined by the voltage difference signal measurement module when controlling the current source to output current to the shielding electrode in the second operating mode; and determine the electric field synthesis ratio parameter based on the first voltage difference information and the second voltage difference information.

[0007] In some embodiments, the acquisition and control module is used to calculate the ratio of the first voltage difference information to the second voltage difference information, and determine the electric field synthesis ratio parameter based on the ratio.

[0008] In some embodiments, the system includes a reference electrode; the acquisition control module is configured to detect, in the first operating mode, a first voltage of the transmitting electrode relative to the reference electrode and a first shunt current flowing into the target formation; detect, in the second operating mode, a second voltage of the transmitting electrode relative to the reference electrode and a second shunt current flowing into the transmitting electrode; and determine the apparent resistivity based on the electrode coefficient, the first voltage, the second voltage, the first shunt current, the second shunt current, and the ratio.

[0009] In some embodiments, the transmitting electrode is the cutterhead of the tunnel boring machine; the shielding electrode includes the shield of the tunnel boring machine; the return electrode includes a first ground anchor inserted into the stratum; and the reference electrode includes a second ground anchor inserted into the stratum.

[0010] In some embodiments, the ground anchor correction module is used to jointly adjust the electric field synthesis ratio parameter and the electrode coefficient when the positions of the first ground anchor and / or the second ground anchor change.

[0011] In some embodiments, the differential pressure signal measurement module includes multiple amplification circuits and an adder circuit; the amplification circuits are used to detect and amplify the differential pressure signal between the transmitting electrode and the shielding electrode; the adder circuits are used to add the differential pressure signals output by each of the amplification circuits to generate the voltage differential pressure information.

[0012] In some embodiments, the current output by the current source to the transmitting electrode in a first operating mode includes a current having a first frequency; the current output by the current source to the shielding electrode in a second operating mode includes a current having a second frequency.

[0013] According to a second aspect of this disclosure, a tunnel geological detection method is provided, applied to a tunnel geological detection system. The tunnel geological detection system includes a current source, a transmitting electrode, a shielding electrode, a return electrode, a differential pressure signal measurement module, and an acquisition and control module. A detection loop corresponding to a first operating mode includes the transmitting electrode and the return electrode, and a detection loop corresponding to a second operating mode includes the shielding electrode and the return electrode. The differential pressure signal measurement module is used to detect the voltage difference between the transmitting electrode and the shielding electrode, and to determine voltage differential information based on the voltage difference. The tunnel geological detection method is executed in the acquisition and control module, including: determining an electric field synthesis ratio parameter; controlling the current source to output current to the transmitting electrode in a first operating mode, and controlling the current source to output current to the shielding electrode in a second operating mode, so that the transmitting electrode emits current to the target stratum under the superposition of electric fields; wherein, when the transmitting electrode emits current to the target stratum, the voltage differential information is less than a differential pressure threshold; and determining the apparent resistivity corresponding to the target stratum.

[0014] In some embodiments, determining the electric field synthesis ratio parameter includes: when controlling the current source to output current to the transmitting electrode in the first operating mode, acquiring first voltage difference information determined by the voltage difference signal measurement module; when controlling the current source to output current to the shielding electrode in the second operating mode, acquiring second voltage difference information determined by the voltage difference signal measurement module; and determining the electric field synthesis ratio parameter based on the first voltage difference information and the second voltage difference information.

[0015] In some embodiments, determining the electric field synthesis ratio parameter based on the first voltage difference information and the second voltage difference information includes: calculating the ratio of the first voltage difference information to the second voltage difference information; and determining the electric field synthesis ratio parameter based on the ratio.

[0016] In some embodiments, the tunnel geological exploration system includes a reference electrode; determining the apparent resistivity corresponding to the target stratum includes: detecting a first voltage of the transmitting electrode relative to the reference electrode and a first shunt current flowing into the target stratum in a first operating mode; detecting a second voltage of the transmitting electrode relative to the reference electrode and a second shunt current flowing into the transmitting electrode in a second operating mode; and determining the apparent resistivity based on the electrode coefficient, the first voltage, the second voltage, the first shunt current, the second shunt current, and the ratio.

[0017] In some embodiments, the transmitting electrode is the cutterhead of the tunnel excavation equipment; the shielding electrode includes the shield of the tunnel excavation equipment; the return electrode includes a first ground anchor inserted into the stratum; the reference electrode includes a second ground anchor inserted into the stratum; the tunnel geological detection method further includes: when the positions of the first ground anchor and / or the second ground anchor change, jointly adjusting the electric field synthesis ratio parameter and the electrode coefficient.

[0018] In some embodiments, the current output by the current source to the transmitting electrode in a first operating mode includes a current having a first frequency; the current output by the current source to the shielding electrode in a second operating mode includes a current having a second frequency.

[0019] According to a third aspect of this disclosure, a computer-readable storage medium is provided that stores computer instructions which are executed by a processor using the method described above.

[0020] According to a fourth aspect of this disclosure, a computer program product is provided, the computer program product storing computer instructions, the instructions being executed by a processor using the method described above. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments or related technologies of this disclosure, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0022] Figure 1 is a schematic diagram of some embodiments of the tunnel geological exploration system according to the present disclosure;

[0023] Figure 2 is a schematic diagram of the control current source outputting current to the transmitting electrode in a first operating mode according to some embodiments of the tunnel geological exploration system of the present disclosure;

[0024] Figure 3 is a schematic diagram of the control current source outputting current to the shielded electrode in a second operating mode according to some embodiments of the tunnel geological exploration system of this disclosure;

[0025] Figure 4 is a schematic diagram of the output current of the transmitting electrode under electric field synthesis in some embodiments of the tunnel geological exploration system according to the present disclosure;

[0026] Figure 5 is a schematic diagram of a differential pressure signal measurement module in some embodiments of the tunnel geological exploration system according to the present disclosure;

[0027] Figure 6 is a schematic flowchart of some embodiments of the tunnel geological exploration method according to the present disclosure. Detailed Implementation

[0028] Exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of the embodiments are described in the specification. However, it should be understood that many implementation-specific settings must be made in carrying out the embodiments to achieve the developer's specific goals, such as complying with constraints related to the device and business, and these constraints may vary depending on the implementation. Furthermore, it should be understood that while development work can be very complex and time-consuming, such development work is merely a routine task for those skilled in the art who benefit from the present disclosure.

[0029] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this disclosure.

[0030] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of this disclosure are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0031] It should also be understood that in the embodiments disclosed herein, "a plurality of" may refer to two or more, and "at least one" may refer to one, two or more.

[0032] It should also be understood that any component, data or structure mentioned in the embodiments of this disclosure can generally be understood as one or more unless expressly defined or given to the contrary in the context.

[0033] Furthermore, the term "and / or" in this disclosure is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this disclosure generally indicates that the preceding and following related objects have an "or" relationship.

[0034] It should also be understood that the description of the various embodiments in this disclosure emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0035] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0036] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0037] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0039] Furthermore, to avoid obscuring this disclosure with unnecessary detail, only processing steps and / or apparatus structures closely related to at least the solutions according to this disclosure are shown in the accompanying drawings, while other details less relevant to this disclosure are omitted. It should also be noted that similar reference numerals and letters in the drawings indicate similar items, and therefore once an item is defined in one drawing, it need not be discussed again in subsequent drawings.

[0040] In the related technologies known to the inventors, when using BEAM technology, a hardware circuit negative feedback method is usually used to focus the emitted current so that the emitting electrode and the shielding electrode meet the focusing conditions. Since the gain of the hardware circuit is finite, there will inevitably be a residual potential difference between the emitting electrode and the shielding electrode under this hardware circuit negative feedback method, which will reduce the accuracy of the measured apparent resistivity. Furthermore, in order to implement the BEAM function in tunnel excavation equipment, the relevant hardware circuit for negative feedback needs to be pre-installed on the tunnel excavation equipment before it leaves the factory, which is difficult to implement. For tunnel excavation equipment that has already been put into use, the relevant hardware circuit for negative feedback also needs to be installed, which makes the implementation process even more difficult and costly.

[0041] In view of this, one technical problem to be solved by this application is to provide a tunnel geological detection system that uses software focusing technology to turn two non-focused current fields into a focused current field, which can avoid the potential difference between the emitting electrode and the shielding electrode, improve the measurement accuracy of apparent resistivity, and provide accurate geological prediction results; moreover, it can enable tunnel excavation equipment to have tunnel geological detection function without the need to install related hardware circuits, which is simple to implement and can reduce costs.

[0042] In some embodiments, as shown in FIG1, this disclosure provides a tunnel geological detection system, including a transmitting electrode 11, a shielding electrode 12, a return electrode 13, a current source 15, a differential pressure signal measurement module 17, and an acquisition and control module 16, etc. The detection circuit corresponding to the first working mode includes the transmitting electrode 11 and the return electrode 13, etc., and the detection circuit corresponding to the second working mode includes the shielding electrode 12 and the return electrode 13, etc.

[0043] The differential pressure signal measurement module 17 detects the voltage difference between the transmitting electrode 11 and the shielding electrode 12, and determines the voltage differential information based on the voltage difference. The tunnel geological exploration system may also include a reference electrode 14, which is used to measure the voltage of the transmitting electrode 11, the shielding electrode 12, etc., as a reference voltage.

[0044] The acquisition and control module 16 determines the electric field synthesis ratio parameters, which can be determined using various methods. Based on the electric field synthesis ratio parameters, the acquisition and control module 16 controls the current source 15 to output current to the transmitting electrode 11 in a first operating mode, and also controls the current source 15 to output current to the shielding electrode 12 in a second operating mode, so that the transmitting electrode 11 emits current towards the target formation under the superposition of electric fields, thereby determining the apparent resistivity corresponding to the target formation.

[0045] The acquisition and control module 16 can predict geological information such as the integrity and water content of the target formation by analyzing changes in apparent resistivity. When the transmitting electrode transmits current to the target formation, if the voltage difference information determined by the voltage difference signal measurement module 17 is less than the voltage difference threshold, the voltage difference threshold can be set; for example, it can be close to 0. When the voltage difference threshold is close to 0, the voltage difference information determined by the voltage difference signal measurement module 17 can be considered as 0.

[0046] Tunnel boring machines (TBMs) are highly complex pieces of equipment widely used in the construction of underground tunnel projects. Tunnel excavation equipment can take many forms, such as shield tunneling machines (TBMs). It can include multiple components, such as a cutterhead, shield, hydraulic propulsion system, and segment assembly system.

[0047] The transmitting electrode 11 includes the cutterhead of the tunnel excavation equipment, and the shielding electrode 12 includes the shield of the tunnel excavation equipment. Various existing electrode configuration methods can be used, with the cutterhead serving as the transmitting electrode 11 and the shield as the shielding electrode 12. The return electrode 13 and the reference electrode 14 can be various types of electrodes; for example, a first ground anchor inserted into the formation can serve as the return electrode 13, and a second ground anchor inserted into the formation can serve as the reference electrode 14.

[0048] When the current source 15 supplies power to a detection circuit including the transmitting electrode 11 and the return electrode 13, the current source 15 transmits current in a first operating mode; when the current source 15 supplies power to a detection circuit including the shielding electrode 12 and the return electrode 13, the current source 15 transmits current in a second operating mode.

[0049] The acquisition and control module 16 determines the electric field synthesis ratio parameters. When the current source 15 transmits current using a synthesis method combining the first and second operating modes, it controls the synthesis ratio between the first and second operating modes to ensure that the voltage difference information determined by the voltage difference signal measurement module 17 is 0 or approximately zero. The current output by the current source 15 to the transmitting electrode in the first operating mode includes a current with a first frequency; the current output by the current source 15 to the transmitting electrode in the second operating mode includes a current with a second frequency; the first frequency and the second frequency can be the same or different.

[0050] When the acquisition and control module 16 controls the current source 15 to output current to the transmitting electrode 11 in the first working mode and controls the current source 15 to output current to the shielding electrode 12 in the second working mode according to the electric field synthesis ratio parameter, the current of the transmitting electrode 11 is focused (electric field superposition) by the current of the shielding electrode 12 and transmits current to the target formation; the target formation can be a formation perpendicular to the transmitting electrode 11, etc.

[0051] The acquisition and control module 16 determines the apparent resistivity corresponding to the target stratum and uses various existing methods to determine the geological conditions of the target stratum based on the apparent resistivity, enabling geological prediction processing. For example, if the target stratum is perpendicular to the tunnel face and located in front of the tunnel face, the resistivity changes of the stratum in front of the tunnel face are sensitive and less affected by the resistivity of the stratum behind and to the side of the tunnel boring machine, allowing for better detection of the geological conditions in front of the tunnel face.

[0052] The tunnel geological detection system disclosed herein employs software focusing technology to transform two non-focused current fields into a focused current field. This avoids a potential difference between the emitting electrode and the shielding electrode, improves the measurement accuracy of apparent resistivity, and provides accurate geological prediction results for construction. Furthermore, it eliminates the need to install relevant hardware circuits for negative feedback on the tunnel excavation equipment, thus enabling the tunnel excavation equipment to have tunnel geological detection capabilities. This simplifies implementation and reduces costs.

[0053] The acquisition and control module 16 can determine the electric field synthesis ratio parameters using various methods. When the control current source 15 outputs current to the transmitting electrode 11 in the first operating mode, the acquisition and control module 16 acquires the first voltage difference information determined by the voltage difference signal measurement module 17; when the control current source 15 outputs current to the shielding electrode 12 in the second operating mode, the acquisition and control module 16 acquires the second voltage difference information determined by the voltage difference signal measurement module 17.

[0054] The acquisition and control module 16 determines the electric field synthesis ratio parameters based on the first voltage difference information and the second voltage difference information. For example, the acquisition and control module 16 calculates the ratio of the first voltage difference information and the second voltage difference information, and determines the electric field synthesis ratio parameters based on the ratio.

[0055] As shown in Figure 2, the tunnel geological detection system includes a (emitting) electrode A0, a (shielding) electrode A1, a return electrode 13, and a reference electrode 14. The cutterhead of the tunnel boring machine (TBM) can serve as the emitting electrode, which is electrode A0; the shield of the TBM can serve as the shielding electrode, which is electrode A1; a first ground anchor placed behind the TBM and inserted into the ground can serve as the return electrode 13; a second ground anchor placed behind the TBM and inserted into the ground can serve as the reference electrode 14. For example, the return electrode 13 and the reference electrode 14 can be arranged approximately 300 meters behind the TBM, using ground anchors inserted into the strata, with the return electrode 13 and the reference electrode 14 approximately 10 meters apart. A differential pressure signal measurement module 17 for measuring the pressure difference between the shield and the cutterhead can be arranged on the inner side of the shield, near the cutterhead.

[0056] When current flows from the cutterhead into the shield, or vice versa, a voltage difference signal is generated between the cutterhead and the shield due to the resistance between them. In the first operating mode, the acquisition and control module 16 controls the current source 15 to supply power to electrode A0 (cutterhead) at a first frequency. The total supply current is I. After flowing into the cutterhead, the current is divided into two parts: one part, I0, flows directly into the formation, and the other part, I1, flows into electrode A1 (shield) via a Rogowski coil, and then into the formation. According to Kirchhoff's current law, I = I0 + I1. The current source 15 will generate a potential V0 on electrode A0. The first frequency can be 10Hz, etc.

[0057] The differential pressure signal measurement module 17 amplifies, suppresses noise, and filters the differential pressure signal between the shield and the cutterhead. It then adds the processed signals to obtain the differential pressure signal VV1 (first voltage differential information), which is sent to the acquisition and control module 16. The acquisition and control module 16 measures the emission current of the current source 17 and the voltage V0 of the motor A0 relative to the N electrode. The acquisition and control module 16 can use various existing methods to measure the voltage V0.

[0058] As shown in Figure 3, in the second operating mode, the acquisition and control module 16 controls the current source 15 to supply power to electrode A1 (shield) at a second frequency. The total power supply current is I'. After flowing into the shield, the current is divided into two parts: one part, I1', flows directly into the ground, and the other part, I0', flows into electrode A0 (cutterhead) via a Rogowski coil, and then into the ground. According to Kirchhoff's current law, I' = I0' + I1', and the current source 15 will generate a potential V0' on electrode A0. The second frequency can be 100Hz, etc.

[0059] Current source 15 is used to supply power to electrode A0 and return electrode 13, or electrode A1 and return electrode 13. Under the control of acquisition and control module 16, current source 15 can generate current signals of two frequencies, and each current signal is a sinusoidal signal with adjustable frequency, amplitude, and phase. Supplying power to electrode A0 and return electrode 13 with a current of the first frequency constitutes operation in the first operating mode, while supplying power to electrode A1 and return electrode 13 with a current of the second frequency constitutes operation in mode 2.

[0060] The differential pressure signal measurement module 17 amplifies, suppresses noise, and filters the differential pressure signal between the shield and the cutterhead. The processed signals are then summed to obtain the differential pressure signal VV2 (second voltage differential information). The acquisition and control module 16 measures the emitted current of the current source and the voltage V0' of the motor A0 relative to the N electrode.

[0061] The acquisition and control module 16 can detect and obtain voltage V0, current I0, current I1, voltage V0', current I0', and current I1' through various measuring devices. The acquisition and control module 16 can amplify, filter, and perform analog-to-digital conversion on the voltage V0, current I0, current I1, voltage V0', current I0', and current I1' to obtain processed voltage and current information. The acquisition and control module 16 can also perform low-pass filtering, 50Hz power frequency interference filtering, harmonic signal adaptive notch filtering, and DFT (Digital Fourier Transform) on the processed voltage and current information to obtain corresponding voltage and current information.

[0062] The acquisition control module 16 detects the first voltage V0 of the transmitting electrode 11 relative to the reference electrode 14 and the first shunt current I0 flowing into the target formation in the first working mode; the acquisition control module 16 detects the second voltage V0' of the transmitting electrode relative to the reference electrode and the second shunt current I0' flowing into the transmitting electrode in the second working mode.

[0063] An electric field can be synthesized from two or more electric fields through linear superposition. According to the principle of electric field synthesis, the first operating mode and the second operating mode are synthesized in a ratio of 1:λ to form a synthesized electric field, where λ is the electric field synthesis ratio parameter. Various existing methods can be used to synthesize the current of the first operating mode and the current of the second operating mode in a ratio of 1:λ.

[0064] The synthesis relationship between the first working mode and the second working mode, which are combined at a ratio of 1:λ, is shown in Formula 1 below:

[0065] In the first working mode and the second working mode, a first voltage difference information VV1 and a second voltage difference information VV2 are generated between electrode A1 (shield) and electrode A0 (cutter disk), respectively. By setting the electric field synthesis ratio parameter λ, the first working mode and the second working mode form a synthesis mode with a ratio of 1:λ, which can make VV1+λVV2=0.

[0066] In the synthesis mode, the potential of electrode A0 is V0+λV0', and the current flowing from electrode A0 into the formation is I0+λI0'; let VV1+λVV2=0, VV1=-λVV2, and the electric field synthesis ratio parameter... λ is calculated from VV1 and VV2, which can be obtained by measurement.

[0067] As shown in Figure 4, when the electric field synthesis ratio parameter λ is At that time, the first working mode and the second working mode are combined in a ratio of 1:λ to form a composite mode. λ is composed of... Therefore, we can determine 1:λ.

[0068] In the composite mode, the voltage difference between electrode A1 (shield) and electrode A0 (cutterhead) is zero. The composite mode is in a focusing state. The current flowing out of electrode A1 forces the current flowing out of electrode A0 to enter the target formation in front of it perpendicularly. The focusing state is the equipotential state of the cutterhead and the shield. In this state, the polarity of the cutterhead and the shield is the same. The current flowing out of the cutterhead is repelled by the current flowing out of the shield and can flow into the target formation in front of the face of the tunnel boring machine.

[0069] The acquisition and control module 16 determines the apparent resistivity based on the electrode coefficient K, the first voltage V0, the second voltage V0', the first shunt current I0, the second shunt current I0', and the ratio of the first voltage difference information VV1 and the second voltage difference information VV2 generated between electrode A1 (shield) and electrode A0 (cutterhead). The apparent resistivity corresponding to the target stratum reflects the geological conditions of the target stratum, and the apparent resistivity can be determined by formula 2:

[0070] Where Ra is the apparent resistivity of the target formation, and K is the electrode coefficient, which is a constant.

[0071] According to the principle of electric field synthesis, the first operating mode and the second operating mode are combined in a certain ratio (1:λ) to form a combined mode. The electric field synthesis method simultaneously uses the first operating mode to supply current to the transmitting electrode and the second operating mode to supply current to the shielding electrode, with both operating modes operating concurrently.

[0072] In the first operating mode, the differential pressure signal measurement module 17 amplifies, suppresses noise, and filters the differential pressure signal between the shield and the cutterhead. The processed signals are then summed to obtain the differential pressure signal VV1. The measured cutterhead voltage and the current flowing out of the cutterhead are V0 and I0, respectively. In the second operating mode, the differential pressure signal measurement module 17 amplifies, suppresses noise, and filters the differential pressure signal between the shield and the cutterhead. The processed signals are then summed to obtain the differential pressure signal VV1. The measured cutterhead voltage and the current flowing out of the cutterhead are V0' and I0', respectively.

[0073] In some embodiments, the differential pressure signal measurement module includes multiple amplification circuits and an adder circuit; each amplification circuit detects and amplifies the differential pressure signal between the transmitting electrode and the shielding electrode, and the adder circuit adds the differential pressure signals output by each amplification circuit to generate voltage differential pressure information.

[0074] The differential pressure signal measurement module can be a low-noise amplifier circuit array used to measure the voltage difference signal between the shield and the cutterhead. The module consists of multiple low-noise amplifier circuits and an adder circuit. Depending on the size of the tunnel boring machine (TBM), different numbers of low-noise amplifier circuits can be arranged near the cutterhead on the shield. As shown in Figure 5, the amplifier circuits are low-noise amplifier circuits, each composed of an instrumentation amplifier, a power frequency notch filter, a bandpass filter, etc. Multiple low-noise amplifier circuits measure and process the differential pressure signal between the shield electrode A1 and the transmitting electrode A0 respectively, and then add them together through the adder module to form the final differential pressure signal (voltage differential information).

[0075] In some embodiments, the tunnel geological exploration system further includes a ground anchor correction module, which is used for the linkage dynamic calibration of the electric field synthesis ratio parameter λ and the electrode coefficient K. This can solve the problem of jumping values ​​of apparent resistivity R and frequency domain induced polarization parameter PFE (Polarization Frequency Effect) after the position of the first ground anchor and / or the second ground anchor changes.

[0076] After the position of the first anchor and / or the second anchor changes, the anchor correction module collects in real time the voltage difference information (VV1, VV2), shunt current (I0, I0') and electrode voltage (V0, V0') corresponding to the new position of the first anchor and / or the second anchor, according to the dual working mode (first working mode and second working mode).

[0077] The ground anchor correction module can use various methods to jointly adjust the electric field synthesis ratio parameter and the electrode coefficient. By dynamically updating the electric field synthesis ratio parameter λ (λ = -VV1 / VV2) and simultaneously correcting the electrode coefficient K in the apparent resistivity calculation model (Formula 2) (the change in electrode contact resistance caused by the change in the position of the first ground anchor and / or the second ground anchor can be adaptively compensated by the value of K), the linkage adjustment and calibration of λ and K can be achieved, thereby suppressing the jump of PFE value from the focusing source.

[0078] During the joint adjustment of the electric field synthesis ratio parameter and the electrode coefficient, the ground anchor correction module ensures that the pressure difference signal (VV1+λVV2) between the transmitting electrode and the shielding electrode is always less than the pressure difference threshold (the pressure difference threshold is close to 0) through the principle of electric field superposition. While correcting the electric field synthesis ratio parameter and the electrode coefficient, it maintains the equipotential focusing state, and there is no secondary fluctuation after the PFE value is corrected.

[0079] The tunnel geological detection system disclosed herein employs software focusing technology to transform two non-focused current fields into a focused current field. This avoids a potential difference between the emitting electrode and the shielding electrode, improving the measurement accuracy of apparent resistivity. It boasts advantages such as high measurement accuracy and strong real-time performance, providing accurate geological prediction results for construction. Furthermore, the tunnel geological detection system can be easily mounted on tunnel boring machines (TBMs) awaiting deployment, eliminating the need for negative feedback hardware circuitry, thus enabling TBMs to perform tunnel geological detection. This simplifies implementation and reduces costs.

[0080] Figure 6 is a flowchart of some embodiments of the tunnel geological detection method of this disclosure, applied to a tunnel geological detection system. The tunnel geological detection method is executed in the acquisition and control module of the tunnel geological detection system, including:

[0081] Step S601: Determine the electric field synthesis ratio parameters.

[0082] The electric field synthesis ratio parameters can be determined using various methods. For example, when the control current source outputs current to the transmitting electrode in the first operating mode, the first voltage difference information determined by the voltage difference signal measurement module is obtained; when the control current source outputs current to the shielding electrode in the second operating mode, the second voltage difference information determined by the voltage difference signal measurement module is obtained.

[0083] The electric field synthesis ratio parameter is determined based on the first voltage difference information and the second voltage difference information. For example, the ratio of the first voltage difference information and the second voltage difference information is calculated, and the electric field synthesis ratio parameter is determined based on the ratio.

[0084] Step S602: According to the electric field synthesis ratio parameter, control the current source to output current to the transmitting electrode in the first working mode, and control the current source to output current to the shielding electrode in the second working mode, so that the transmitting electrode emits current to the target formation under the superposition of electric fields; wherein, when the transmitting electrode emits current to the target formation, the voltage difference information is less than the voltage difference threshold.

[0085] Step S603: Determine the apparent resistivity corresponding to the target formation.

[0086] Various methods can be used to determine the apparent resistivity corresponding to the target formation. For example, in a first operating mode, the first voltage of the transmitting electrode relative to the reference electrode and the first shunt current flowing into the target formation are detected; in a second operating mode, the second voltage of the transmitting electrode relative to the reference electrode and the second shunt current flowing into the transmitting electrode are detected; the apparent resistivity is determined based on the electrode coefficient, the first voltage, the second voltage, the first shunt current, the second shunt current, and their ratio. When the positions of the first and / or second anchors change, the electric field synthesis scaling parameters and the electrode coefficients are jointly adjusted.

[0087] In some embodiments, this disclosure provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the methods as described in any of the foregoing embodiments.

[0088] Computer-readable storage media may take the form of any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may, for example, include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples (not an exhaustive list) of readable storage media may include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0089] Embodiments of this disclosure may also be computer program products, including computer program instructions that, when executed by a processor, cause the processor to perform the steps in the methods according to various embodiments of this disclosure described in the "Exemplary Methods" section above.

[0090] The tunnel geological detection system, method, storage medium, and computer program product in the above embodiments employ software focusing technology to transform two non-focused current fields into a focused current field. This avoids a potential difference between the emitting electrode and the shielding electrode, improving the measurement accuracy of apparent resistivity. It has advantages such as high measurement accuracy and strong real-time performance, providing accurate geological prediction results for construction. Furthermore, the tunnel geological detection system can be easily mounted on tunnel boring machines (TBMs) awaiting deployment, eliminating the need for negative feedback hardware circuitry, thus enabling TBMs to perform tunnel geological detection. This simplifies implementation, reduces costs, and improves the user experience.

[0091] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0092] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0093] The block diagrams of devices, apparatuses, devices, and systems disclosed herein are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0094] It should also be noted that in the apparatus, devices, and methods of this disclosure, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions to this disclosure.

[0095] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0096] The above description has been given for illustrative and descriptive purposes. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although several exemplary aspects and embodiments have been discussed above, those skilled in the art will understand that the above embodiments are illustrative only and do not limit the scope of this disclosure. Those skilled in the art will understand that the above embodiments can be combined, modified, or replaced without departing from the scope and spirit of this disclosure.

Claims

1. A tunnel geological detection system, comprising: Current source, transmitting electrode, shielding electrode, return electrode, differential pressure signal measurement module, and acquisition and control module; The detection circuit corresponding to the first operating mode includes the transmitting electrode and the return electrode, and the detection circuit corresponding to the second operating mode includes the shielding electrode and the return electrode; the differential pressure signal measurement module is used to detect the voltage difference between the transmitting electrode and the shielding electrode, and determine the voltage difference information based on the voltage difference; The acquisition and control module is used to determine the electric field synthesis ratio parameters; According to the electric field synthesis ratio parameter, the current source is controlled to output current to the transmitting electrode in a first operating mode, and the current source is controlled to output current to the shielding electrode in a second operating mode, so that the transmitting electrode emits current to the target formation under the action of electric field superposition, in order to determine the apparent resistivity corresponding to the target formation; wherein, when the transmitting electrode emits current to the target formation, the voltage difference information is less than the voltage difference threshold.

2. The tunnel geological exploration system as described in claim 1, wherein, The acquisition and control module is used to acquire first voltage difference information determined by the voltage difference signal measurement module when controlling the current source to output current to the transmitting electrode in the first working mode; acquire second voltage difference information determined by the voltage difference signal measurement module when controlling the current source to output current to the shielding electrode in the second working mode; and determine the electric field synthesis ratio parameter based on the first voltage difference information and the second voltage difference information.

3. The tunnel geological detection system as described in claim 2, wherein, The acquisition and control module is used to calculate the ratio of the first voltage difference information to the second voltage difference information, and determine the electric field synthesis ratio parameter based on the ratio.

4. The tunnel geological exploration system as described in claim 2 or 3, comprising a reference electrode; The acquisition and control module is used to detect, in the first working mode, the first voltage of the transmitting electrode relative to the reference electrode, and the first shunt current flowing into the target formation; Detecting, in the second operating mode, the second voltage of the emitter electrode relative to the reference electrode, and the second shunt current flowing into the emitter electrode; The apparent resistivity is determined based on the electrode coefficient, the first voltage, the second voltage, the first shunt current, the second shunt current, and the ratio.

5. The tunnel geological detection system as described in claim 4, wherein, The transmitting electrode is the cutterhead of the tunnel excavation equipment; the shielding electrode includes the shield of the tunnel excavation equipment; the return electrode includes a first ground anchor inserted into the stratum; and the reference electrode includes a second ground anchor inserted into the stratum.

6. The tunnel geological exploration system as described in claim 5, further comprising: The ground anchor correction module is used to jointly adjust the electric field synthesis ratio parameter and the electrode coefficient when the position of the first ground anchor and / or the second ground anchor changes.

7. The tunnel geological exploration system as described in any one of claims 1 to 6, wherein, The differential pressure signal measurement module includes multiple amplification circuits and an adder circuit; the amplification circuit is used to detect and amplify the differential pressure signal between the transmitting electrode and the shielding electrode; the adder circuit is used to add the differential pressure signals output by each of the amplification circuits to generate the voltage differential pressure information.

8. The tunnel geological detection system as described in any one of claims 1 to 7, wherein, The current source outputs to the transmitting electrode in the first operating mode, including: a current having a first frequency; The current source outputs a current to the shielding electrode in the second operating mode, which includes a current with a second frequency.

9. A tunnel geological detection method, applied to a tunnel geological detection system, the tunnel geological detection system comprising a current source, a transmitting electrode, a shielding electrode, a return electrode, a differential pressure signal measurement module, and a data acquisition and control module; a detection circuit corresponding to a first operating mode comprising the transmitting electrode and the return electrode, and a detection circuit corresponding to a second operating mode comprising the shielding electrode and the return electrode; the differential pressure signal measurement module is used to detect the voltage difference between the transmitting electrode and the shielding electrode, and to determine voltage differential information based on the voltage difference; wherein, The tunnel geological detection method is executed in the acquisition and control module, including: Determine the electric field synthesis ratio parameters; According to the electric field synthesis ratio parameter, the current source is controlled to output current to the transmitting electrode in a first operating mode, and the current source is controlled to output current to the shielding electrode in a second operating mode, so that the transmitting electrode emits current to the target formation under the superposition of electric fields; wherein, when the transmitting electrode emits current to the target formation, the voltage difference information is less than the voltage difference threshold. Determine the apparent resistivity corresponding to the target formation.

10. The tunnel geological detection method as described in claim 9, wherein determining the electric field synthesis ratio parameter includes: When the current source is controlled to output current to the transmitting electrode in the first working mode, the first voltage difference information determined by the voltage difference signal measurement module is obtained; When the current source is controlled to output current to the shielding electrode in the second working mode, the second voltage difference information determined by the voltage difference signal measurement module is obtained; The electric field synthesis ratio parameter is determined based on the first voltage difference information and the second voltage difference information.

11. The tunnel geological detection method as described in claim 10, wherein, Determining the electric field synthesis ratio parameter based on the first voltage difference information and the second voltage difference information includes: Calculate the ratio of the first voltage difference information to the second voltage difference information; The electric field synthesis ratio parameter is determined based on the ratio.

12. The tunnel geological detection method as described in claim 10 or 11, wherein, The tunnel geological exploration system includes a reference electrode; Determining the apparent resistivity corresponding to the target formation includes: Detecting, in the first operating mode, the first voltage of the transmitting electrode relative to the reference electrode, and the first shunt current flowing into the target formation; Detecting, in the second operating mode, the second voltage of the emitter electrode relative to the reference electrode, and the second shunt current flowing into the emitter electrode; The apparent resistivity is determined based on the electrode coefficient, the first voltage, the second voltage, the first shunt current, the second shunt current, and the ratio.

13. The tunnel geological detection method as described in claim 12, wherein, The transmitting electrode is the cutterhead of the tunnel excavation equipment; the shielding electrode includes the shield of the tunnel excavation equipment; the return electrode includes a first ground anchor inserted into the stratum. The reference electrode includes a second ground anchor inserted into the formation; The tunnel geological detection method also includes: When the positions of the first anchor and / or the second anchor change, the electric field synthesis ratio parameter and the electrode coefficient are jointly adjusted.

14. The tunnel geological detection method according to any one of claims 9 to 13, wherein, The current source outputs to the transmitting electrode in the first operating mode, including: a current having a first frequency; The current source outputs a current to the shielding electrode in the second operating mode, which includes a current with a second frequency.

15. A computer-readable storage medium storing computer instructions that are executed by a processor according to any one of claims 9 to 14.

16. A computer program product storing computer instructions that are executed by a processor using the method as described in any one of claims 9 to 14.