A system and method for precise positioning of an anomaly body by drilling

Abstract

The present application relates to geological exploration technical field, specifically, it relates to a kind of with the precision positioning system and method of advanced detection abnormal body of excavation, it includes magnetic field fusion correction unit, for tunnel inside net magnetic field;Magnetic resonance detection unit is used to combine tunnel inside net magnetic field and detects the water content characteristics and porosity characteristics of target stratum position in front of excavation face;Bio-magnetic marker unit injects tracer to target stratum position and continuously monitors, when target stratum position reaches target tracer concentration, generates bio-magnetic signal;Magnetic anomaly positioning feedback unit outputs abnormal body center coordinates, while triggering early warning.The precision positioning system and method of advanced detection abnormal body of excavation, realize the high-precision, low false alarm rate positioning of abnormal body such as water-bearing structure, simultaneously through dynamic integral area adjustment and closed-loop feedback mechanism, significantly improve the real-time and reliability of advanced detection of excavation under complex geological conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geological exploration, in particular to a system and method for precise positioning of abnormal bodies in advance during tunneling. BACKGROUND

[0002] In tunnel engineering, water-bearing structures (such as faults and karst caves) are the most dangerous geological abnormal bodies, but abnormal bodies also include lithology change zones, cavities, etc., and face significant challenges in tunneling detection: first, the dynamic changes of the geomagnetic background and the motion interference of the tunneling equipment cause large magnetic field signal noise, making it difficult to extract the target abnormal characteristics; second, single physical field (such as resistivity) detection has limited recognition ability for water-bearing abnormal bodies and is easily affected by lithology differences; third, traditional passive magnetic monitoring lacks an active signal enhancement mechanism for the target area, resulting in insufficient positioning accuracy of abnormal bodies in low water content or micro-fracture areas.

[0003] Existing technologies often rely on single magnetic measurement or single physical field detection, which are affected by factors such as motion interference on site, geomagnetic background changes, and target physical property differences, making it difficult to achieve high-precision, low-false-alarm abnormal body positioning without stopping the machine. Therefore, a system and method for precise positioning of abnormal bodies in advance during tunneling are provided. SUMMARY

[0004] The present application aims to provide a system and method for precise positioning of abnormal bodies in advance during tunneling to solve the problem of single magnetic measurement or single physical field detection being often affected by factors such as motion interference on site, geomagnetic background changes, and target physical property differences, making it difficult to achieve high-precision, low-false-alarm abnormal body positioning without stopping the machine.

[0005] To achieve the above-mentioned purpose, on the one hand, the present application aims to provide a system for precise positioning of abnormal bodies in advance during tunneling, comprising:

[0006] A magnetic field fusion correction unit is used to collect real-time surface magnetic field data and tunnel original magnetic field data, and introduce a gradient-displacement coupling term to correct the tunnel original magnetic field data to obtain the tunnel net magnetic field.

[0007] A magnetic resonance detection unit is used to trigger and receive nuclear magnetic resonance echoes at the target formation location through a controlled excitation sequence, and detect the water content characteristics and porosity characteristics of the target formation location in front of the tunneling face in combination with the tunnel net magnetic field.

[0008] A biomagnetic marker unit is used to inject a tracer into the target formation location and continuously monitor, and generate a biomagnetic signal when the target formation location reaches the target tracer concentration.

[0009] The magnetic anomaly location feedback unit is used to construct an objective function based on water content characteristics, porosity characteristics and biomagnetic signals, and to perform inversion using total variational regularization, outputting the coordinates of the anomaly center and triggering an early warning.

[0010] As a further improvement to this technical solution, the net magnetic field obtained in the tunnel by the magnetic field fusion correction unit is specifically as follows:

[0011] Surface magnetic field data and raw magnetic field data inside the tunnel were collected using magnetic sensors, respectively.

[0012] A gradient-displacement coupling term is introduced to compensate and correct the interference generated by spatial gradient changes and measuring point displacement in the original magnetic field data inside the tunnel, resulting in corrected magnetic field data inside the tunnel.

[0013] The corrected magnetic field inside the tunnel is fused with the surface reference field, and background components unrelated to the target anomaly are filtered out to obtain the net magnetic field that reflects the true magnetic environment inside the tunnel.

[0014] As a further improvement to this technical solution, the magnetic resonance detection unit includes a controlled excitation module and an echo processing module;

[0015] Among them, the controlled excitation module is used to generate controlled electromagnetic pulses of target frequency and intensity, and periodically excite the target stratum position in front of the tunnel face to excite hydrogen nuclei in the stratum to generate nuclear magnetic resonance time-domain echo signals.

[0016] The echo processing module is used to receive and analyze the generated nuclear magnetic resonance time-domain echo signal. By combining the relaxation time analysis algorithm with the net magnetic field data in the tunnel, it obtains the water content and porosity characteristics of the water-bearing structure at the target stratum.

[0017] As a further improvement to this technical solution, the steps of the echo processing module to retrieve the water content and porosity characteristics of the water-bearing structures at the target stratum are as follows:

[0018] The attenuation portion of the time-domain echo signal is exponentially fitted using a relaxation time analysis algorithm, and the transverse relaxation time is solved using the nonlinear least squares method. and initial signal strength Based on the initial signal strength Obtain a baseline value for the number of hydrogen nuclei; combine this with net magnetic field data within the tunnel, based on... The relationship between spectral distribution and the number of hydrogen nuclei in the formation is used to determine the location of the target formation. Moisture content ,based on Spectral distribution and pore structure models are used to determine the location of the target strata. porosity .

[0019] As a further improvement of the technical solution, in the biomagnetic marker unit, the tracer carries ferromagnetic nanoparticles and has magnetotactic characteristics.

[0020] As a further improvement of the technical solution, the magnetic anomaly positioning feedback unit includes a target judgment module, an advanced drilling control module, and an anomaly fusion positioning module.

[0021] The target judgment module is used to determine whether the target formation position is in a high-risk water-bearing area through the water content feature and the porosity feature. If the target formation position is in a high-risk water-bearing area, a drilling instruction is triggered. If the target formation position is still in a high-risk water-bearing area after the biomagnetic marker unit is marked, anomaly positioning and anomaly warning are triggered.

[0022] The advanced drilling control module is used to displace the drill to the target formation position according to the drilling instruction and control the injection of the tracer of the biomagnetic marker unit.

[0023] The anomaly fusion positioning module detects the intensity of the biomagnetic signal in real time after triggering the anomaly positioning, constructs a target function based on the water content feature, the porosity feature, and the biomagnetic signal, and inverts using total variation regularization to obtain the anomaly body center coordinates.

[0024] As a further improvement of the technical solution, in the target judgment module, the determination of whether the target formation position is in a high-risk water-bearing area through the water content feature and the porosity feature is that the water content feature is greater than a water content threshold and the porosity feature is greater than a porosity threshold.

[0025] As a further improvement of the technical solution, if the anomaly fusion positioning module detects that the intensity of the biomagnetic signal is less than a distortion intensity threshold, a secondary marker signal is generated. The secondary marker signal is transmitted to the advanced drilling control module. If the intensity of the biomagnetic signal is still less than the distortion intensity threshold after the execution of the secondary marker signal, the advanced drilling control module is sent a new offset drilling instruction of the drilling controller. The content of the secondary marker signal includes increasing the injection pressure and increasing the tracer concentration.

[0026] As a further improvement of the technical solution, the specific steps of the anomaly fusion positioning module obtaining the anomaly body center coordinates are as follows:

[0027] S41, multi-source data fusion is performed on the water content feature, the porosity feature, and the biomagnetic signal. Data fitting terms are established at the high-risk water-bearing area and the target formation position, respectively, and total variation regularization is introduced to constrain the spatial distribution stability of the water content, thereby constructing a target function.

[0028] S42, based on the constructed target function, a preconditioned conjugate gradient method is used for iterative optimization to obtain an optimized water content distribution, so that the target function is minimized.

[0029] S43, according to the optimized water content distribution, the weighted centroid coordinates are calculated in the high-risk water-bearing area, and the final anomaly body center coordinates are output combined with the positioning uncertainty of the nuclear magnetic resonance time domain echo signal and the biomagnetic signal.

[0030] In another aspect, the present application provides a precise positioning method for advanced detection of abnormal bodies during excavation, which is used in the precise positioning system for advanced detection of abnormal bodies during excavation described in any one of the above, comprising the following steps:

[0031] S1, real-time acquisition of surface magnetic field data and tunnel original magnetic field data, and introduction of gradient-displacement coupling term to correct the tunnel original magnetic field data to obtain the tunnel net magnetic field;

[0032] S2, triggering and receiving the nuclear magnetic resonance echo at the target stratum position through the controlled excitation sequence, and detecting the water content characteristics and porosity characteristics of the target stratum position in front of the tunneling face combined with the tunnel net magnetic field;

[0033] S3, judging whether the target stratum position is in a high-risk water-bearing area through the water content characteristics and porosity characteristics, and triggering the drilling instruction if the target stratum position is in a high-risk water-bearing area, and displacing the drill to the target stratum position based on the drilling instruction;

[0034] S4, injecting a tracer into the target stratum position based on the drill, and continuously monitoring, generating a biomagnetic signal when the target stratum position reaches the target tracer concentration, and triggering abnormal positioning and abnormal warning if the target stratum position is still in a high-risk water-bearing area after labeling;

[0035] S5, after triggering abnormal positioning, real-time detection of the intensity of the biomagnetic signal, construction of a target function based on the water content characteristics, porosity characteristics and biomagnetic signal, and inversion using total variation regularization to obtain the abnormal body center coordinates.

[0036] Compared with the prior art, the present application has the following advantages:

[0037] In a precise positioning system and method for advanced detection of abnormal bodies during excavation, by fusing biomagnetic labeling, geomagnetic dynamic correction and magnetic resonance constraint technology, the problems of large signal interference and low positioning accuracy in traditional detection during excavation are overcome, the target signal specificity is actively enhanced by biomagnetic labeling, the tunneling motion interference is eliminated in real time by combining with geomagnetic dynamic correction, and accurate water content and porosity parameters are provided through magnetic resonance constraint, a target function of multi-source data fusion is constructed, and total variation regularization inversion algorithm is adopted, realizing high-precision and low-false-alarm-rate positioning of abnormal bodies such as water-bearing structures, and through dynamic integral area adjustment and closed-loop feedback mechanism, the real-time performance and reliability of advanced detection during excavation under complex geological conditions are significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The overall flow chart of the present application;

[0039] Figure 2 The overall method flow chart of the present application;

[0040] The meanings of various labels in the figure are:

[0041] 1, magnetic field fusion correction unit; 2, magnetic resonance detection unit; 21, controlled excitation module; 22, echo processing module; 3, biomagnetic marker unit; 4, magnetic anomaly positioning feedback unit; 41, target judgment module; 42, advanced drilling control module; 43, anomaly fusion positioning module. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0043] Embodiment 1: Please refer to Figure 1 As shown in the figure, a precision positioning system for detecting abnormal bodies in advance during excavation is provided, which comprises a magnetic field fusion correction unit 1, a magnetic resonance detection unit 2, a biomagnetic marker unit 3 and a magnetic anomaly positioning feedback unit 4.

[0044] The magnetic field fusion correction unit 1 is used to collect surface magnetic field data and original tunnel magnetic field data in real time, introduce a gradient-displacement coupling term to correct the original tunnel magnetic field data, and obtain the net magnetic field in the tunnel. The net magnetic field in the tunnel is transmitted to the magnetic resonance detection unit 2, and the background field is provided for the biomagnetic marker unit 3.

[0045] The surface magnetic field data is the surface vector magnetic field time series data obtained by the three-axis magnetic field sensor arranged on the surface above the tunnel; the tunnel magnetic field data is the tunnel vector magnetic field time series data obtained by the three-axis magnetic field sensor arranged on the tunnel excavation face, but different from the surface data, the tunnel magnetic field data contains not only the background geomagnetic field component, but also superimposes:

[0046] Magnetic anomaly caused by geological structure (such as rock mass containing magnetic minerals);

[0047] Electromagnetic interference generated by excavation equipment and electrical devices;

[0048] Disturbance of the tunnel space structure to the magnetic field distribution.

[0049] In the magnetic field fusion correction unit 1, the net magnetic field in the tunnel is obtained as follows:

[0050] The ground magnetic field data and the original tunnel magnetic field data are collected by magnetic sensors respectively;

[0051] The gradient-displacement coupling term is introduced to compensate and correct the interference generated by the spatial gradient change and the displacement of the measuring point in the original tunnel magnetic field data, and the corrected tunnel magnetic field data are obtained; the corrected tunnel magnetic field is fused with the ground reference field to filter out the background components irrelevant to the target anomaly, and the net magnetic field reflecting the real magnetic environment in the tunnel is obtained;

[0052]

[0053] In the formula, When the tunnel net magnetic field is When the tunnel original magnetic field data are When the ground magnetic field data are is the ground magnetic field data influence coefficient; is the magnetic field distortion influence coefficient; When the tunnel magnetic field gradient tensor is When the relative displacement is is the delay time of the ground reference signal to the tunnel end influence; is the magnetic field distortion amount;

[0054] Tunnel clean magnetic field The tunnel clean magnetic field is used to characterize the magnetic characteristics of the tunnel surrounding rock and the geological body in front of it, and is obtained after the original tunnel magnetic field data are corrected by the ground reference field and compensated by the gradient-displacement coupling term. The net magnetic field data effectively suppress the background geomagnetic disturbance and non-geological factor interference, and provide reliable magnetic field input for high-precision positioning of the anomaly body.

[0055] The magnetic resonance detection unit 2 is used to trigger and receive the nuclear magnetic resonance echo at the target stratum position through a controlled excitation sequence, and combines the tunnel net magnetic field to detect the water content characteristics and porosity characteristics of the target stratum position in front of the tunnel face;

[0056] The magnetic resonance detection unit 2 includes a controlled excitation module 21 and an echo processing module 22;

[0057] ​​​​​Among them, the controlled excitation module 21 is used to generate controlled electromagnetic pulses of target frequency and intensity to periodically excite the target stratum position in front of the tunnel face, thereby exciting hydrogen nuclei in the stratum to generate nuclear magnetic resonance time-domain echo signals. After absorbing the energy of the electromagnetic pulse, the hydrogen nuclei undergo energy level transitions and then release energy through a relaxation process to form a detectable time-domain echo signal. The intensity and relaxation time of the wave signal directly reflect the water content and porosity of the stratum.

[0058] The echo processing module 22 is used to receive and analyze the generated nuclear magnetic resonance time-domain echo signal, and obtain the water content characteristics and porosity characteristics of the water-bearing structure at the target stratum by combining the relaxation time analysis algorithm with the net magnetic field data in the tunnel.

[0059] The steps of echo processing module 22 to retrieve the water content and porosity characteristics of water-bearing structures at the target stratum location are as follows:

[0060] The attenuation portion of the time-domain echo signal is exponentially fitted using a relaxation time analysis algorithm, and the transverse relaxation time is solved using the nonlinear least squares method. and initial signal strength Based on the initial signal strength Obtain a baseline value for the number of hydrogen nuclei; combine this with net magnetic field data within the tunnel, based on... The relationship between spectral distribution and the number of hydrogen nuclei in the formation is used to determine the location of the target formation. Moisture content ,based on Spectral distribution and pore structure models are used to determine the location of the target strata. porosity ;

[0061] The attenuation portion of the time-domain echo signal is exponentially fitted using a relaxation time analysis algorithm. The exponential fitting model is as follows:

[0062]

[0063] In the formula, The time-domain echo signal at time t;

[0064] Through experimental data points Fit the best and This minimizes the error between the model and the measured data.

[0065] It is proportional to the total number of hydrogen nuclei in the formation, because the intensity of the nuclear magnetic resonance signal is determined by the collective behavior of the magnetic moments of hydrogen nuclei;

[0066]

[0067] In the formula, water content of the target formation location; target formation location represents the three-dimensional coordinates of the detection point in the formation; initial signal strength of the target formation location, representing the transverse magnetization of hydrogen nuclei in the formation at time ; gyromagnetic ratio of hydrogen nuclei (γ) ); formation density (mass per unit volume) of the target formation location, which varies with spatial location ; transverse relaxation time; gradient-signal response coefficient, determined by laboratory calibration; magnetic field gradient (unit: T / m), generated by the sweep field coil; the above integral term represents the three-dimensional coordinates of the detection point in the formation;

[0068]

[0069] wherein, porosity of the target formation location; control curve steepness; geometric mean of the target formation location spectrum, representing the weighted average of the relaxation time of hydrogen nuclei in the formation, which can distinguish between mobile fluid and bound fluid through the geometric mean of the spectrum; threshold offset (to distinguish between large pores and small pores); gradient-porosity coupling coefficient, which corrects the influence of the magnetic field gradient on the porosity distribution; the coupling term of the magnetic field gradient and the spatial location corrects the spatial non-uniformity of the signal integral and the porosity, eliminating the error caused by the non-uniformity of the magnetic field.

[0070] The biomagnetic marker unit 3 is used to inject a tracer into the target formation location and continuously monitor, and generates a biomagnetic signal when the target formation location reaches the target tracer concentration; the injection time, volume, location, concentration, and biomagnetic signal are recorded. By actively injecting a tracer into the target formation location and achieving full-process monitoring, the migration and enrichment behavior of the tracer in the formation can be dynamically mastered, ensuring that the detection process has a clear time-space-concentration correspondence; the biomagnetic signal is generated when the tracer concentration reaches the preset threshold, avoiding misjudgment under background noise interference and improving the reliability and repeatability of the detection signal; at the same time, the injection parameters (time, volume, location, concentration) and the response signal (biomagnetic signal) are recorded synchronously, providing complete data chain support for subsequent anomaly body inversion positioning, enhancing the data traceability and analysis reliability of the system.

[0071] The target concentration is greater than or equal to 10 9CFU / cm³; setting the minimum effective concentration threshold of the tracer in the water-bearing structure ensures that the tracer microorganism forms a sufficient density of biomagnetic sources in the target area, thereby generating a magnetic anomaly signal that can be effectively identified by a far-field sensor; this concentration threshold is based on experimental verification of the magnetic magnetosome production capacity of microorganisms and the adsorption characteristics of the formation, which can not only ensure that the signal strength meets the detection sensitivity requirements, but also avoid resource waste and environmental disturbance caused by excessive injection, achieving a balance between detection sensitivity and engineering economy.

[0072] In the biomagnetic labeling unit 3, the tracer carries ferromagnetic nanoparticles and has magnetotactic characteristics; the tracer used carries natural or artificially synthesized ferromagnetic nanoparticles (such as magnetite nanocrystals) and has the directional migration ability of magnetotactic microorganisms, enabling it to actively enrich in the water-bearing channel or fracture zone under the guidance of an external weak magnetic field or hydraulic gradient, significantly enhancing the magnetic signal contrast of the target area; this feature breaks through the diffusion limitations of traditional passive tracing, enhances the spatial focusing ability of the tracer, thereby improving the positioning accuracy of the anomaly body, and is particularly suitable for fine identification of microfractures or low-permeability water-bearing areas.

[0073] The magnetic anomaly positioning feedback unit 4 is used to construct a target function based on the water content characteristics, porosity characteristics, and biomagnetic signals and to perform inversion using total variation regularization to output the anomaly body center coordinates and trigger an early warning at the same time;

[0074] The magnetic anomaly positioning feedback unit 4 includes a target judgment module 41, an advanced drilling control module 42, and an anomaly fusion positioning module 43.

[0075] The target judgment module 41 is used to determine whether the target formation location is in a high-risk water-bearing area through the water content characteristics and the porosity characteristics, and if the target formation location is in a high-risk water-bearing area, a drilling instruction is triggered, and if the target formation location is still in a high-risk water-bearing area after the biomagnetic labeling unit 3 labels, an anomaly positioning and anomaly early warning are triggered.

[0076] In the target judgment module 41, determining whether the target formation location is in a high-risk water-bearing area through the water content characteristics and the porosity characteristics specifically means that the water content characteristics are greater than a water content threshold and the porosity characteristics are greater than a porosity threshold.

[0077] This module uses a hierarchical response strategy: when it is determined that the target formation location is in a high-risk water-bearing area, the advanced drilling control module 42 immediately performs directional drilling to reduce the risk of water inrush. If the biomagnetic labeling feedback indicates that the risk has not been eliminated, the anomaly fusion positioning module 43 outputs the anomaly body center coordinates through total variation regularization inversion and links the early warning terminal (such as an audible and visual alarm, data push), achieving precise positioning and real-time intervention.

[0078] The advanced drilling control module 42 is used to displace the drill bit to the target stratum position according to the drilling instruction, control the injection of the biomagnetic marker unit 3 tracer, and accurately displace the drill bit to the target stratum position according to the drilling instruction of the target judgment module 41, perform the advanced drilling operation, and reduce the water inrush risk. After the secondary marker signal is triggered by the anomaly fusion positioning module 43, the injection parameters of the biomagnetic marker unit 3 are dynamically adjusted to realize the intensified injection of the tracer and improve the biomagnetic signal strength. If the signal is still insufficient after the secondary marker, the detection range is expanded by adding the offset drilling instruction to cover the potential unidentified anomaly body, thereby ensuring the detection integrity.

[0079] The anomaly fusion positioning module 43 detects the strength of the biomagnetic signal in real time after triggering the anomaly positioning, constructs a target function based on the water content characteristics, porosity characteristics and biomagnetic signal, and performs inversion by using total variation regularization to obtain the anomaly body center coordinates;

[0080] If the anomaly fusion positioning module 43 detects that the strength of the biomagnetic signal is less than the distortion strength threshold, a secondary marker signal is generated and transmitted to the advanced drilling control module 42. If the strength of the biomagnetic signal is still less than the distortion strength threshold after the secondary marker signal is executed, the advanced drilling control module 42 is sent an offset drilling instruction of the drill bit controller. The content of the secondary marker signal includes increasing the injection pressure and increasing the tracer concentration. The closed-loop feedback link of signal detection-parameter optimization-drilling intervention is formed to ensure the stability of the system under complex stratum conditions. The triggering mechanism of the offset drilling instruction enhances the adaptability of the system to unknown anomaly bodies.

[0081] The specific steps of the anomaly fusion positioning module 43 for obtaining the anomaly body center coordinates are as follows:

[0082] S41, multi-source data fusion is performed on the water content characteristics, porosity characteristics and biomagnetic signal, data fitting terms are established in the high-risk water-bearing area and the target stratum position, and total variation regularization is introduced to constrain the spatial distribution stability of the water content. The target function is associated with physical parameters through a proportional coefficient and an empirical formula, and combined with an adaptive regularization parameter to realize high-precision inversion positioning of the anomaly body;

[0083] ;

[0084] In the formula, the water content and the porosity are to-be-inverted variables; The signal amplitude (V) at the position is measured by the magnetic resonance detection unit 2; is the biomagnetic signal at the observation position ; is a linear operator that maps the water content distribution to the biomagnetic field distribution; is a total variation regularization term for water saturation, used to stabilize inversion and preserve boundaries; is a regularization strength; is a sensitivity of decay time to porosity; is a minimum effective porosity threshold;

[0085]

[0086] Total variation regularization suppresses spatial oscillation of water saturation (e.g. false high water saturation points caused by noise); preserves sharp boundaries of water-bearing structures (e.g. water channel interfaces);

[0087] is a high-risk water-bearing area, a three-dimensional spatial range to be probed in front of the excavation face, the specific boundary of which is determined by the effective probing depth of the magnetic resonance probing unit; is a target stratum position, a set of spatial positions of the magnetic sensor array arranged in the tunnel; wherein the first integral is in the anomaly body region , is a three-dimensional space bounded by the maximum probing distance in front of the excavation face, the second integral is performed on the observation surface (the position of the receiving array arranged in the tunnel), determined by the arrangement position of the magnetic sensor array in the tunnel; wherein the maximum probing distance and the sensor arrangement parameters are configured according to the detection accuracy requirement.

[0088] S42, based on the constructed multi-source fusion objective function, an iterative optimization is performed using a preconditioned conjugate gradient method to obtain an optimized water saturation distribution, so that the objective function is minimized; specifically comprising:

[0089] Set the initial value of the water saturation and porosity distribution, and load the measured data of the magnetic resonance probing unit and the biomagnetic marker unit 3;

[0090] In each iteration, the gradient direction of the objective function to the water saturation and porosity distribution is calculated, and a preconditioning matrix is combined to accelerate convergence;

[0091] The parameters are updated along the gradient direction according to the preset step size until the convergence condition (relative error less than or the maximum number of iterations is reached) is met;

[0092] In each iteration, a total variation regularization term is applied to suppress noise and preserve the boundary features of the water saturation distribution. The iterative optimization algorithm (such as the preconditioned conjugate gradient method) automatically adapts to complex stratum conditions, adjusts the inversion parameters in real time, and ensures that the coordinates can still be stably output under the interference of excavation.

[0093] S43, according to the optimized water content distribution, the weighted centroid coordinates in the high-risk water-bearing area are calculated, the final anomaly body center coordinates are output combined with the positioning uncertainty of the nuclear magnetic resonance time domain echo signal and the biomagnetic signal; and As the weight function:

[0094]

[0095]

[0096] In the formula, is the centroid of the water-bearing structure; is the final anomaly body center coordinates; is the positioning uncertainty of the nuclear magnetic resonance time domain echo signal; is the positioning uncertainty of the biomagnetic signal; is the extreme point position of the biomagnetic signal; the final coordinates are calculated by combining the positioning uncertainty of the magnetic resonance and the biomagnetic signal, overcoming the limitations of a single data source and reducing the false alarm rate.

[0097] Embodiment 2: Please refer to Figure 2 As shown in the figure, a method for precise positioning of an anomaly body in advance of tunneling is provided, and the method is used for the precise positioning system of an anomaly body in advance of tunneling in any one of the above embodiments, and includes the following steps:

[0098] S1, real-time acquisition of surface magnetic field data and tunnel original magnetic field data, and introduction of a gradient-displacement coupling term to correct the tunnel original magnetic field data to obtain the tunnel net magnetic field;

[0099] S2, triggering and receiving the nuclear magnetic resonance echo at the target stratum position through the controlled excitation sequence, and detecting the water content characteristics and porosity characteristics of the target stratum position in front of the tunneling face combined with the tunnel net magnetic field;

[0100] S3, determining whether the target stratum position is in a high-risk water-bearing area through the water content characteristics and porosity characteristics, and if the target stratum position is in a high-risk water-bearing area, triggering a drilling instruction and displacing the drill to the target stratum position based on the drilling instruction;

[0101] S4, injecting a tracer into the target stratum position based on the drill and continuously monitoring, generating a biomagnetic signal when the target stratum position reaches the target tracer concentration, and if the target stratum position is still in a high-risk water-bearing area after labeling, triggering anomaly positioning and anomaly warning;

[0102] S5, after triggering the anomaly positioning, real-time detection of the intensity of the biomagnetic signal, construction of a target function based on the water content characteristics, porosity characteristics and biomagnetic signal, and inversion using total variation regularization to obtain the anomaly body center coordinates.

[0103] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A system for precise positioning of anomalies detected during excavation, characterized in that, include: Magnetic field fusion correction unit (1) is used to collect surface magnetic field data and original magnetic field data in the tunnel in real time, and introduce gradient-displacement coupling term to correct the original magnetic field data in the tunnel to obtain the net magnetic field in the tunnel. Magnetic resonance detection unit (2), the magnetic resonance detection unit (2) is used to trigger and receive nuclear magnetic resonance echoes at the target stratum location through controlled excitation sequence, and combine the net magnetic field inside the tunnel to detect the water content and porosity characteristics of the target stratum location in front of the tunnel face; Biomagnetic labeling unit (3), the biomagnetic labeling unit (3) is used to inject tracer into the target formation location and continuously monitor it, and generate a biomagnetic signal when the target formation location reaches the target tracer concentration; The magnetic anomaly location feedback unit (4) is used to construct an objective function based on water content characteristics, porosity characteristics and biomagnetic signals and to perform inversion using total variational regularization, output the coordinates of the center of the anomaly, and trigger an early warning.

2. The precise positioning system for anomaly detection during tunneling as described in claim 1, characterized in that: In the magnetic field fusion correction unit (1), the net magnetic field inside the tunnel is obtained as follows: Surface magnetic field data and raw magnetic field data inside the tunnel were collected using magnetic sensors, respectively. A gradient-displacement coupling term is introduced to compensate and correct the interference generated by spatial gradient changes and measuring point displacement in the original magnetic field data inside the tunnel, resulting in corrected magnetic field data inside the tunnel. The corrected magnetic field inside the tunnel is fused with the surface reference field, and background components unrelated to the target anomaly are filtered out to obtain the net magnetic field that reflects the true magnetic environment inside the tunnel.

3. The precise positioning system for anomaly detection during excavation as described in claim 2, characterized in that: The magnetic resonance detection unit (2) includes a controlled excitation module (21) and an echo processing module (22). Among them, the controlled excitation module (21) is used to generate controlled electromagnetic pulses of target frequency and intensity, and periodically excite the target stratum position in front of the tunnel face to excite the hydrogen nuclei in the stratum to generate nuclear magnetic resonance time-domain echo signals. The echo processing module (22) is used to receive and analyze the generated nuclear magnetic resonance time-domain echo signal, and obtain the water content characteristics and porosity characteristics of the water-bearing structure at the target stratum by combining the relaxation time analysis algorithm with the net magnetic field data in the tunnel.

4. The precise positioning system for anomaly detection during excavation as described in claim 3, characterized in that: The steps of the echo processing module (22) to retrieve the water content and porosity characteristics of the water-bearing structures at the target stratum are as follows: The attenuation portion of the time-domain echo signal is exponentially fitted using a relaxation time analysis algorithm, and the transverse relaxation time is solved using the nonlinear least squares method. and initial signal strength Based on the initial signal strength Obtain a baseline value for the number of hydrogen nuclei; combine this with net magnetic field data within the tunnel, based on... The relationship between spectral distribution and the number of hydrogen nuclei in the formation is used to determine the location of the target formation. Moisture content ,based on Spectral distribution and pore structure models are used to determine the location of the target strata. porosity .

5. The precise positioning system for anomaly detection during excavation as described in claim 4, characterized in that: In the biomagnetic labeling unit (3), the tracer carries ferromagnetic nanoparticles and has magnetotactic properties.

6. The precise positioning system for anomaly detection during tunneling as described in claim 5, characterized in that: The magnetic anomaly positioning feedback unit (4) includes a target judgment module (41), an advanced drilling control module (42), and an anomaly fusion positioning module (43). Among them, the target judgment module (41) is used to determine whether the target stratum is in a high-risk water-bearing area by water content characteristics and porosity characteristics. If the target stratum is in a high-risk water-bearing area, a drilling command is triggered. If the target stratum is still in a high-risk water-bearing area after being marked by the biomagnetic marker unit (3), anomaly location and anomaly warning are triggered. The advanced drilling control module (42) is used to move the drill bit to the target formation position according to the drilling command and control the injection of tracer in the biomagnetic labeling unit (3); After triggering anomaly localization, the anomaly fusion localization module (43) detects the intensity of the biomagnetic signal in real time, constructs an objective function based on water content characteristics, porosity characteristics and biomagnetic signal, and uses total variational regularization to perform inversion to obtain the coordinates of the anomaly center.

7. The precise positioning system for anomaly detection during tunneling as described in claim 6, characterized in that: In the target judgment module (41), the location of the target stratum is determined by water content characteristics and porosity characteristics to determine whether it is in a high-risk water-bearing area. Specifically, the water content characteristics are greater than the water content threshold and the porosity characteristics are greater than the porosity threshold.

8. The precise positioning system for anomaly detection during tunneling as described in claim 7, characterized in that: If the abnormal fusion positioning module (43) detects that the intensity of the biomagnetic signal is less than the distortion intensity threshold, it generates a secondary marking signal and transmits the secondary marking signal to the advanced drilling control module (42). If the intensity of the biomagnetic signal is still less than the distortion intensity threshold after the secondary marking signal is executed, it sends a drilling controller additional offset drilling instruction to the advanced drilling control module (42). The content of the secondary marking signal includes increasing the injection pressure and increasing the tracer concentration.

9. The precise positioning system for anomaly detection during tunneling as described in claim 8, characterized in that: The specific steps for the anomaly fusion localization module (43) to obtain the coordinates of the anomaly center are as follows: S41. Multi-source data fusion of water content characteristics, porosity characteristics and biomagnetic signals is performed. Data fitting terms are established in high-risk water-bearing areas and target formation locations respectively. Total variational regularization is introduced to constrain the spatial distribution stability of water content, thereby constructing the objective function. S42. Based on the constructed objective function, the preconditional conjugate gradient method is used for iterative optimization to obtain the optimized water content distribution, thereby minimizing the objective function; S43. Based on the optimized water content distribution, calculate the weighted centroid coordinates in the high-risk water-bearing area, and output the final anomaly center coordinates by combining the location uncertainty of the nuclear magnetic resonance time-domain echo signal and the biomagnetic signal.

10. A method for precise positioning of anomalies detected during tunneling, used in a precise positioning system for anomalies detected during tunneling as described in any one of claims 1-9, characterized in that: Includes the following steps: S1. Real-time acquisition of surface magnetic field data and original magnetic field data inside the tunnel, and introduction of gradient-displacement coupling term to correct the original magnetic field data inside the tunnel to obtain the net magnetic field inside the tunnel. S2. Trigger and receive nuclear magnetic resonance echoes at the target stratum location through a controlled excitation sequence, and combine the net magnetic field inside the tunnel to detect the water content and porosity characteristics of the target stratum location in front of the tunnel face. S3. Determine whether the target formation is located in a high-risk water-bearing zone by analyzing the water content and porosity characteristics. If the target formation is located in a high-risk water-bearing zone, trigger a drilling command and move the drill bit to the target formation location based on the drilling command. S4. Based on the drilling tool, a tracer is injected into the target formation location and continuously monitored. When the target formation location reaches the target tracer concentration, a biomagnetic signal is generated. If the target formation location is still in a high-risk water-bearing area after marking, anomaly location and anomaly warning are triggered. S5. After triggering anomaly localization, the intensity of the biomagnetic signal is detected in real time. Based on water content characteristics, porosity characteristics and biomagnetic signal, an objective function is constructed and inversion is performed using total variational regularization to obtain the coordinates of the anomaly center.

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