A method, device, medium and terminal for advanced geological prediction of tunnel excavation

Abstract

A method for advanced geological prediction during tunneling involves selecting a transverse section behind the tunnel face and placing a measuring point at each of four locations on the tunnel rock wall. A differential measurement is performed between the measuring point at the tunnel face center and any measuring point on the tunnel rock wall. The location with the largest signal difference among the four sets of electromagnetic response signal differences is used as the background location. Based on these measurement results, the electromagnetic response signal differences between the measuring points at three other locations on the tunnel rock wall and the measuring point at the tunnel face center relative to the background location are calculated. These four differences are then compared, and the response signal difference with the largest absolute amplitude and the slowest amplitude decay over time is selected to interpret the location and distribution characteristics of water- or mineral-bearing anomalies. This method utilizes a dual differential measurement mode, which overcomes both primary field interference generated by the transceiver coils and background interference generated by the surrounding rock itself. The resulting response signal difference data has an extremely high signal-to-noise ratio, provides higher resolution for geological hazards, and provides more accurate and reliable detection results.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering measurement and discloses a method, equipment, medium and terminal for advanced geological prediction of tunnel excavation. Background Art

[0002] During underground engineering construction or mining operations, tunnel faces, stop / heads, and surrounding areas often harbor engineering geological hazards such as water storage structures and fracture zones. Compared to advance drilling, advance geological prediction is a fast and cost-effective geophysical prospecting technique for identifying engineering geological hazards, and is widely welcomed by production units. However, improving its detection accuracy requires adapting to local conditions and adopting scientific technical methods. Compared with other technical methods such as seismic advance geological prediction and electrical advance geological prediction, electromagnetic advance prediction uses electromagnetic induction. Electromagnetic induction coils or sensors do not require additional construction to be placed in the surrounding rock mass, resulting in more efficient detection operations.

[0003] However, numerous practices have shown that the operating environment for electromagnetic geological prospecting is quite complex, facing interference from both the electromagnetic response of various metal components and background electrical variations caused by the complex and unknown geological conditions of the surrounding rock. The former can be overcome to a certain extent during construction, but the latter is difficult to predict and is a major challenge to be addressed in advanced geological exploration. Differences in the type or state of the surrounding rock medium often lead to significant variations in its electrical parameters. If the normal surrounding rock electromagnetic response background cannot be accurately extracted and the surrounding rock response cannot be distinguished from the abnormal response of hidden dangers, the reliability of the advanced geological exploration results and the ability to distinguish hidden danger anomalies will be greatly reduced. Therefore, there is an urgent need to develop an advanced geological prospecting method that can accurately identify abnormal geological hazards. Summary of the Invention

[0004] In response to the deficiencies in the prior art, the present invention provides a method, equipment, medium and terminal for advanced geological prediction of tunnel excavation to solve the problems of difficulty in distinguishing between normal surrounding rock response and abnormal response of hidden dangers, and insufficient accuracy of detection results.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for advanced geological prediction of tunnel excavation, comprising the following steps:

[0007] Arrange one measuring point at the center of the tunnel face;

[0008] Select a cross section parallel to the tunnel face behind the tunnel face, and arrange one measuring point in each of the four directions of the tunnel rock wall: the left side, top, right side, and bottom.

[0009] Using the electromagnetic method, differential measurement is performed between the measuring point at the center of the tunnel face and any measuring point on the tunnel rock wall. The electromagnetic response signal difference between the measuring point at the center of the tunnel face and each measuring point on the tunnel rock wall is obtained. The tunnel rock wall orientation where the maximum electromagnetic response signal difference R0 is located is marked as the background orientation.

[0010] Calculate the electromagnetic response signal differences (Ri) at the other three locations on the tunnel wall relative to the background location (i = 1, 2, or 3). Select the electromagnetic response signal difference with the largest absolute amplitude and the slowest amplitude decay over time from Ri and R0. Use the electromagnetic response interpretation algorithm to interpret the location and distribution of the anomaly. The larger the absolute amplitude or the slower the amplitude decay over time, the more severe the anomaly is predicted to be at that location.

[0011] Furthermore, the electromagnetic method is one of the transient electromagnetic method, the frequency depth sounding electromagnetic method with variable frequency or frequency combination, and the geological radar method.

[0012] Furthermore, when using the electromagnetic method for differential measurement, a set of integrated transceiver electromagnetic coils is installed at each of the two measuring points; in the two sets of transceiver electromagnetic coils, the transmitting coil is connected to the transmitting end of the electromagnetic detector in series or in parallel, and the receiving coil is connected to the receiving end of the electromagnetic detector in series or in parallel.

[0013] Furthermore, the transceiver mode of the two sets of transceiver integrated electromagnetic coils is one of one transmit and one receive, one transmit and two receive, two transmit and one receive, and two transmit and two receive.

[0014] Furthermore, in the transceiver integrated electromagnetic coil, the transmitting coil or the receiving coil adopts a magnetic rod with a built-in soft magnetic core or a Hall sensor; or, the transmitting coil is a power supply electrode and the receiving coil is a receiving electrode.

[0015] Furthermore, the electromagnetic response interpretation algorithm adopts one of the following methods: one-dimensional electromagnetic inversion method, two-dimensional electromagnetic inversion method, three-dimensional electromagnetic inversion method, early apparent resistivity conversion algorithm, late apparent resistivity conversion algorithm, power spectrum anomaly analysis method, and entropy spectrum anomaly analysis method.

[0016] Furthermore, when abnormal geology is predicted to exist ahead of the measuring point at the center of the tunnel face, the orientation of the abnormal geology ahead of the measuring point at the center of the tunnel face is further predicted using the following method:

[0017] Using the measuring point at the center of the tunnel face as a reference, one measuring point is placed in each of the four directions within the tunnel face: up, down, left, and right. Using electromagnetic methods, differential measurements are performed between any measuring point on the tunnel face and the background measuring point. The electromagnetic response signal difference between each measuring point and the background measuring point is obtained. The signal difference with the largest absolute amplitude and the slowest amplitude decay over time is selected, and an electromagnetic response interpretation algorithm is used to interpret the location and distribution characteristics of the anomaly. The larger the absolute amplitude or the slower the amplitude decay over time, the more severe the anomaly in the corresponding direction is predicted to be.

[0018] In a second aspect, the present invention provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the method for advanced geological prediction of tunnel excavation.

[0019] In a third aspect, the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the method for advanced geological prediction of tunnel excavation.

[0020] In a fourth aspect, the present invention provides an information data processing terminal, which is used to implement the method for advanced geological prediction of tunnel excavation.

[0021] The technical principle of the present invention is as follows: Compared with normal rock and soil media, engineering geological hazards, including water storage structures, fracture zones, etc., and metal mineral resources generally have lower resistivity. In the alternating electromagnetic field, electromagnetic induction (eddy current effect) will be formed, thereby hindering the change of the excitation electromagnetic field (primary field). That is, the presence of water-rich engineering geological hazards and metal mineral resources will reduce the speed of change of the excitation electromagnetic field that increases or decreases with time. Typically, during transient electromagnetic measurement, the presence of low-resistivity geological hazards or minerals will prevent the secondary field from immediately decaying to zero after the primary field is turned off. Not only will there be a strong response amplitude, but the signal will also decay slowly. The lower the resistivity of the geological hazard or mineral or the larger the volume, the greater the abnormal response amplitude, the slower the decay process, or the longer it takes to decay to zero.

[0022] When electromagnetic detection is actually used in underground tunnels, due to the mutual induction of the transmitting and receiving coils due to their proximity, even if there is no good conductive geological body, there will be a strong mutual induction electromagnetic signal in the receiving coil, which will seriously interfere with or even cover the response of the good conductive geological body, thereby reducing the resolution of the good conductive geological body. The present invention eliminates the mutual induction interference of the transmitting and receiving coils at the analog signal level by performing reverse series connection or parallel subtraction of signals through a pair of transmitting and receiving integrated coils with the same specifications; in addition, hidden geological bodies exist inside the surrounding rock, and the background response interference caused by the geological conditions of the surrounding rock is another major problem to be solved in geological detection. Effectively eliminating the normal electromagnetic response background of the surrounding rock will greatly improve the reliability of the abnormal detection results obtained. The present invention uses the response signal difference of the four directions of the tunnel face relative to the tunnel or the four directions including the tunnel face relative to the background direction to perform anomaly analysis, and also eliminates the response background interference caused by the geological conditions of the surrounding rock at the analog signal level; as mentioned above, double differential measurement improves the signal-to-noise ratio of the abnormal signal and the quality of the detection data, thereby improving the accuracy and resolution of the detection results.

[0023] Compared with the prior art, the present invention has the following beneficial technical effects:

[0024] 1) Using paired transceiver electromagnetic coils combined with electromagnetic detection instruments for differential detection, the primary field response signals of the two sets of receiving coils are directly offset, first eliminating the interference of the mutual inductance of the transceiver coils; secondly, the two sets of transceiver electromagnetic coils are attached to the surface of the surrounding rock, and the differential measurement process further eliminates the response background interference generated by the surrounding rock itself. Double differential or differential measurement is achieved in one operation, and the signal-to-noise ratio of abnormal signals is higher; the combination of the two differential modes improves the quality of detection data and provides a guarantee for hidden danger judgment and analysis.

[0025] 2) The operating mode of confirming the background first and then the relative anomaly is adopted, which greatly improves the detection results and anomaly resolution capabilities.

[0026] 3) The construction operation is convenient and can adapt to various complex working conditions.

[0027] 4) A single detection operation can not only achieve advanced geological prediction in front of the tunnel face, but also detect hidden dangers in the surrounding rock, killing two birds with one stone. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flowchart of the method for advanced geological prediction of tunnel excavation.

[0029] Figure 2Schematic diagram of the method for advanced geological prediction of tunnel excavation according to the present invention; in the figure, R Palm represents the measuring point at the center of the tunnel face; R Left, R Right, R Top, and R Bottom respectively represent measuring points on the left, right, top, and bottom of the tunnel rock wall corresponding to a certain cross section behind the tunnel face.

[0030] Figure 3 Schematic diagram of the detailed detection of hidden dangers on the tunnel face according to the advanced geological prediction method of the present invention. In the figure, Rpalm Up, Rpalm Down, Rpalm Left, and Rpalm Right respectively represent measuring points at the upper, lower, left, and right directions within the tunnel face; Rb represents a background direction measuring point.

[0031] Figure 4 It is the electromagnetic response signal difference data of the center measuring point of the tunnel face relative to the four azimuth measuring points on the tunnel rock wall in Example 1.

[0032] Figure 5 It is the electromagnetic response signal difference data of the three azimuth measuring points on the tunnel rock wall and the center measuring point of the tunnel face relative to the background azimuth measuring point in Example 1.

[0033] Figure 6 This is the apparent resistivity profile in Example 1. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0035] Example 1

[0036] This embodiment is an advanced geological prediction of hidden floods ahead of a tunnel excavation face in a certain traffic tunnel.

[0037] See also Figures 1 to 6 The potential for hidden flooding ahead of the tunnel face in a traffic tunnel under construction requires advance geological forecasting. Transient electromagnetic method (TEM) and TEM measuring instruments are used for advanced geological forecasting.

[0038] The present invention provides a method for advanced geological prediction of tunnel excavation, comprising the following steps:

[0039] Arrange one measuring point at the center of the tunnel face;

[0040] Select a cross section parallel to the tunnel face behind the tunnel face, and arrange one measuring point in each of the four directions corresponding to the left, top, right, and bottom of the tunnel rock wall on the cross section, forming four directions of up, down, left, and right relative to the center measuring point of the tunnel face;

[0041] Using the electromagnetic method, differential measurement is performed between the measuring point at the center of the tunnel face and any measuring point on the tunnel rock wall. The electromagnetic response signal difference between the measuring point at the center of the tunnel face and each measuring point on the tunnel rock wall is obtained. The direction where the maximum electromagnetic response signal difference R0 is located is marked as the tunnel rock wall background direction.

[0042] The electromagnetic response signal differences Ri of the other three azimuth measuring points on the tunnel rock wall relative to the background azimuth measuring point are calculated respectively, where i=1, 2, and 3. The electromagnetic response signal difference with the largest absolute amplitude and the slowest amplitude decay over time is selected from Ri and R0, and the electromagnetic response interpretation algorithm is used to interpret the location and distribution characteristics of the abnormal geological conditions.

[0043] Based on the difference between the electromagnetic response signals with the largest absolute amplitude and the amplitude with the slowest decay over time, one or two directions can be obtained, which correspond to a certain tunnel rock wall measurement point or tunnel face measurement point. The direction of the abnormal geology refers to the direction (one or two) of the abnormal geology finally determined based on the difference between the one or two electromagnetic response signals obtained. The distribution characteristics refer to the depth range of the abnormal geology at this direction and the low-resistance hidden danger characteristics.

[0044] Specifically, first, stand facing the tunnel face and select a cross section parallel to the tunnel face. The distance between the measuring point section and the tunnel face is 0-10m. Taking the center of the measuring point section as the reference, construct four directions on the rock wall around the tunnel: left, top, right, and bottom. Place one measuring point in each direction to form four directions relative to the tunnel face: top, bottom, left, and right. Figure 2 It should be noted that Figure 2 The middle tunnel face has a rectangular cross-section, but the rectangular cross-section is only for reference, to show the four directions, and does not represent the actual tunnel cross-section.

[0045] Then, a pair of electromagnetic induction coils with consistent electromagnetic response physical properties are taken, one set of which is placed at the center measuring point of the tunnel face, and the other set of electromagnetic coils is moved along the rock walls around the tunnel to measure the left, top, right and bottom azimuth measuring points in sequence. The transmitting coil and the receiving coil in the two sets of electromagnetic coils are connected in series in a forward direction and in a reverse direction respectively, and then connected to the corresponding receiving end and transmitting end of the electromagnetic detector to form a differential measurement mode; the electromagnetic coils use overlapping loops; and the measurement is moved in sequence to obtain the electromagnetic response signal difference between the center measuring point of the tunnel face and the azimuth measuring points on the left, top, right and bottom of the tunnel rock wall.

[0046] Assume that the receiving electromagnetic response of a set of transceiver electromagnetic coils at the center of the tunnel face is Rpalm, and the receiving electromagnetic response signals of the corresponding receiving coils at each azimuth measuring point are Rleft, Rtop, Rright, and Rbottom. The response of the set of transceiver coils at the tunnel face is taken as positive "+";

[0047] The electromagnetic response signal difference data of the tunnel face relative to the tunnel rock wall obtained by the electromagnetic detector are: R palm-R left, R palm-R top, R palm-R right, R palm-R bottom;

[0048] Compare the corresponding response difference data of the above azimuth measurement points, take the azimuth data with the maximum value of "+", and mark it as: R0=Rpalm-Rb;

[0049] R0 is the azimuth of the maximum response difference, and the azimuth of the measuring point Rb is the azimuth of the minimum abnormal electromagnetic response. This azimuth is set as the azimuth where no hidden dangers may exist and is selected as the background azimuth;

[0050] The measurement results of this embodiment are as follows Figure 4 , Figure 4 The electromagnetic response signal difference between the measuring point at the center of the tunnel face and the measuring points at four azimuths of the tunnel rock wall; Figure 4 In the figure, “left side” represents the electromagnetic response signal difference “R palm - R left”, “right side” represents the electromagnetic response signal difference “R palm - R right”, “top” represents the electromagnetic response signal difference “R palm - R top”, and “bottom” represents the electromagnetic response signal difference “R palm - R bottom”. It should be noted that Figure 4 There are four groups of signal differences, and the vertical axis starting point of each group of signal difference curves (i.e. V( t ) / I=0) are different. On the vertical axis, from top to bottom, they are the starting points of "R palm-R bottom", "R palm-R right", "R palm-R top", and "R palm-R left". As can be seen from the figure, the "left" and "top" correspond to the signal difference curve V( t ) / I is mostly less than 0, and the “bottom” and “right” correspond to the signal difference curve V( t ) / I is greater than 0, and the peak value of the "bottom" signal difference curve is greater than that of the "right side". Therefore, the response signal difference of the measuring point at the "bottom" of the tunnel rock wall is the largest. Therefore, the bottom measuring point is taken as the measuring point Rb, and the bottom orientation is the background orientation.

[0051] Further obtain the response data of other orientations relative to the background orientation of the tunnel rock wall measuring point Rb:

[0052] Subtract the electromagnetic response signal difference data corresponding to other azimuth measuring points from R0, that is, subtract R palm - R left, R palm - R top, and R palm - R right from R0 = R palm - Rb. Since the set of transceiver electromagnetic coils arranged at the measuring point at the center of the tunnel face remains stationary during the differential measurement process, the receiving response of the measuring point at the center of the tunnel face represented by R palm is the same, so the electromagnetic response signal difference data of R1 = R left - Rb, R2 = R top - Rb, and R3 = R right - Rb are obtained. The electromagnetic response signal difference data of the measuring point at the center of the tunnel face relative to the background azimuth measuring point Rb is R0 = R palm - Rb. The electromagnetic response signal differences of the three azimuth measuring points on the tunnel rock wall and the measuring point at the center of the tunnel face relative to the background azimuth measuring point are as follows: Figure 5 In the figure, "left side" represents the signal difference R1=Rleft-Rb, "top" represents the signal difference R2=Rtop-Rb, "right side" represents the signal difference R3=Rright-Rb, and "palm" represents the signal difference R0=Rpalm-Rb. The vertical axis starting point of each group of signal difference curves (i.e., V( t ) / I=0) are all different. On the vertical axis, from top to bottom they are R0, R3, R2, and R1.

[0053] Compare the amplitude changes of R0, R1, R2, and R3. The more prominent the amplitude change, the greater the possibility and scale of the hidden danger. The comparison of amplitude change includes two aspects: one is the size of the absolute amplitude, and the other is the speed at which the amplitude decays over time. The larger the absolute amplitude, that is, the larger the abnormal response amplitude (the stronger the energy that hinders the decay of the primary field or the slower the decay of the time-varying abnormal field), the greater the abnormal degree or scale of the low-resistance hidden danger (possibly the better the conductivity, the larger the volume, or the closer to the detection working surface); the smaller the speed at which the amplitude decays over time (or the slower the decay), also indicates that the abnormal degree or scale is greater.

[0054] In this embodiment, Figure 5 It can be seen that the electromagnetic response signal difference R3 = Rright - Rb has the smallest absolute amplitude and decays rapidly over time, followed by the electromagnetic response signal difference R0 = Rpalm - Rb. The electromagnetic response signal difference R1 = Rleft - Rb has the slowest amplitude decay over time, and the electromagnetic response signal difference R2 = Rtop - Rb has the largest absolute amplitude. The amplitude changes of R1 and R2 are the most prominent. The location and distribution of geological anomalies around the corresponding azimuth measurement points are then interpreted based on the electromagnetic response signal differences R1 and R2.

[0055] This embodiment uses the late apparent resistivity conversion algorithm for interpretation. The calculation formula for the late apparent resistivity of the overlapping loop is:

[0056] ρ = 6.32×10 -3 ×L 4 / 3 S 2 / 3 ×[V(t) / I]-2 / 3 × t -5 / 3

[0057] in: ρ is the apparent resistivity, in Ω·m; L is the coil side length, in m; S is the receiving area, in m 2 ; V( t ) / I is the data value of the normalized electromagnetic response signal difference, the unit is uV / A; t It is the tracking time (i.e. the time required for the electromagnetic response signal to reach the corresponding depth), in ms.

[0058] like Figure 6 , Figure 6 This is a pseudo-section of apparent resistivity obtained by converting the late apparent resistivity calculation formula (the transceiver coil is an overlapping loop). White represents the location with low resistivity, black represents the location with high resistivity, and gray represents the transition from black to white. Figure 6 It can be seen that the apparent resistivity is highest at the bottom and right side of the tunnel, indicating no water storage hazards (the diagrams of the tunnel bottom and right side are for comparison and verification purposes only and do not require interpretation during implementation). The apparent resistivity is lower on the left and top of the tunnel, preliminarily indicating the presence of water storage hazards. The apparent resistivity on the left side (the left measurement point relative to the measurement point at the center of the tunnel face) is even lower, indicating a greater likelihood and scale of the hazard. Specifically, low-resistivity hazards primarily exist on the left side, roughly divided into two sections. The most serious low-resistivity hazard exists at depths of 80-90m, particularly in the 85-95m range. Low-resistivity hazards also exist at depths of 100m and deeper, but their low-resistivity values ​​are lower than those at depths of 80-90m.

[0059] Traffic tunnels generally refer to construction tunnels for subways, high-speed railways, and highways. The low-resistance hidden dangers they face are generally concealed water storage structures. These water disasters may exist in karst caves and fault fracture zones.

[0060] When measuring using the transient electromagnetic method, the response of the secondary electromagnetic field (including the response of low-resistivity hidden dangers that may exist within the detected area) is measured at the moment the primary electromagnetic field is turned off. If there are no low-resistance hidden dangers nearby, the secondary electromagnetic field will quickly decay to zero. When the secondary electromagnetic field slowly decays to zero, it means that there are low-resistance hidden dangers (such as water-rich water bodies) nearby. The slower the decay, the larger the scale of the hidden danger, the better the water-richness, or the closer the distance. In the present invention, differential measurement is first performed between the measuring point at the center of the tunnel face and each measuring point on the tunnel rock wall to obtain electromagnetic response signal difference data (such as Rpalm-Rleft) to eliminate interference from the primary electromagnetic field signal. Then, based on the attenuation law of the secondary electromagnetic field, the direction at which the maximum response difference occurs is determined as the background direction (R0=Rpalm-Rb). The surrounding rock mass revealed by the background direction is the most normal, and the probability of the existence of low-resistance hidden dangers around the measuring point Rb is the lowest. Based on this background direction, R1, R2, R3, and R0 are compared, and the electromagnetic response signal difference with the largest absolute amplitude and the slowest amplitude decay over time is selected from Ri and R0. In this way, the presence of low-resistance hidden dangers, i.e., abnormal geology or mineral resources, is determined in the corresponding direction.

[0061] In other embodiments, a water storage hazard may be predicted at a measuring point in front of the tunnel face's center. The following method can be used to further predict the location of the geological anomaly in front of the tunnel face: using the aforementioned background measurement point (e.g., bottom) as a reference and the tunnel face center measurement point as a benchmark, one measurement point is placed in each of the four directions (upper, lower, left, and right) within the tunnel face (close to the tunnel face contour). Electromagnetic differential measurements are performed between any measurement point in the tunnel face and the background measurement point. Measurements can be performed in the upper, lower, left, and right directions to determine the electromagnetic response signal difference between each measurement point in the tunnel face and the background measurement point. Based on the electromagnetic response signal difference with the largest difference, an electromagnetic response interpretation algorithm is used to interpret the location of the geological anomaly. The larger the difference, the more accurate the location of the geological anomaly obtained using the corresponding electromagnetic response signal difference interpretation.

[0062] It should be noted that the above-mentioned advanced geological prediction method can be used in the excavation projects of underground mining tunnels, including metal, non-metallic mines and coal mines, to predict the water storage structure in front of the tunnel face and implement advanced geological exploration; it can also be used in the excavation projects of underground mining tunnels to predict the detection of hidden mineral resources around the tunnels, including the face, especially the detection of metal ore bodies.

[0063] It should be noted that the method of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware portion can be implemented using dedicated logic; the software portion can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. Those skilled in the art will understand that the above-mentioned devices and methods can be implemented using computer-executable instructions and / or contained in processor control code, for example, such codes are provided on a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The device of the present invention and its modules can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, or can be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0064] The instruments, equipment, electromagnetic methods, and interpretation methods used in this invention all utilize existing technologies. The improvement lies in cleverly applying these technologies to advanced geological exploration, using the methods described in this invention, to improve the accuracy of the detection results. The improvements to its implementation are based on these improvements, and the supporting hardware and software can refer to existing technologies.

[0065] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any modifications or replacements made to the technical solution by other technicians in this professional field should be included in the scope of the claims of the present invention as long as they do not depart from the connotation of the technical solution of the present invention.

Claims

1. A method for advanced geological prediction for tunnel excavation, characterized by: The steps include: Arrange one measuring point at the center of the tunnel face; Select a cross section parallel to the tunnel face behind the tunnel face, and arrange one measuring point in each of the four directions on the left, top, right, and bottom of the tunnel rock wall on the cross section. Using the electromagnetic method, differential measurement is performed between the measuring point at the center of the tunnel face and any measuring point on the tunnel rock wall. The electromagnetic response signal difference between the measuring point at the center of the tunnel face and each measuring point on the tunnel rock wall is obtained. The tunnel rock wall orientation where the maximum electromagnetic response signal difference R0 is located is marked as the background orientation. The electromagnetic response signal differences Ri of the other three azimuth measuring points on the tunnel rock wall relative to the background azimuth measuring point are calculated respectively, where i=1, 2, and 3. The electromagnetic response signal difference with the largest absolute amplitude and the slowest amplitude decay over time is selected from Ri and R0, and the electromagnetic response interpretation algorithm is used to interpret the location and distribution characteristics of the abnormal geological conditions.

2. The method according to claim 1, wherein: The electromagnetic method is one of a transient electromagnetic method, a frequency depth sounding electromagnetic method with variable frequency or a frequency combination, and a geological radar method.

3. The method according to claim 1, wherein: When using the electromagnetic method for differential measurement, a set of transceiver electromagnetic coils are installed at each of the two measuring points; in the two sets of transceiver electromagnetic coils, the transmitting coil is connected to the transmitting end of the electromagnetic detector in series or parallel, and the receiving coil is connected to the receiving end of the electromagnetic detector in series or parallel.

4. The method according to claim 3, wherein: The two sets of electromagnetic coils for transmitting and receiving are used in a transmitting and receiving mode selected from one of: one transmitting and one receiving; one transmitting and two receiving; two transmitting and one receiving; and two transmitting and two receiving.

5. The method according to claim 3, wherein: In the transceiver integrated electromagnetic coil, the transmitting coil or the receiving coil both adopts a magnetic rod with a built-in soft magnetic core or a Hall sensor; or, the transmitting coil is a power supply electrode and the receiving coil is a receiving electrode.

6. The method according to claim 1, wherein: The electromagnetic response interpretation algorithm adopts one of a one-dimensional electromagnetic inversion method, a two-dimensional electromagnetic inversion method, a three-dimensional electromagnetic inversion method, an early apparent resistivity conversion algorithm, a late apparent resistivity conversion algorithm, a power spectrum anomaly analysis method, and an entropy spectrum anomaly analysis method.

7. The method according to claim 1, wherein: When abnormal geology is predicted ahead of the measuring point at the center of the tunnel face, the location of the abnormal geology ahead of the measuring point at the center of the tunnel face is further predicted using the following method: Taking the measuring point at the center of the tunnel face as the reference, one measuring point is arranged in each of the four directions (up, down, left, and right) within the tunnel face. The electromagnetic method is used to perform differential measurement between any measuring point at any direction of the tunnel face and the measuring point at the background direction. The electromagnetic response signal difference between each measuring point at any direction of the tunnel face and the background direction is obtained. The response signal difference with the largest absolute amplitude and the slowest amplitude decay over time is selected, and the electromagnetic response interpretation algorithm is used to interpret the location and distribution characteristics of the abnormal geological characteristics.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the method according to any one of claims 1 to 7.

9. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor is caused to perform the method according to any one of claims 1 to 7.

10. An information data processing terminal, configured to implement the method according to any one of claims 1 to 7.

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