A dam monitoring method and system based on magnetotelluric method

Abstract

The present application relates to the technical field of dam monitoring, and particularly relates to a dam monitoring method and system based on magnetotelluric method, which determines a monitoring area of a dam and a target frequency value corresponding to the monitoring area; a plurality of detection points in a same straight line are arranged in the monitoring area, a midpoint between two adjacent detection points is a collection point, and then a detection electrode is embedded in the detection point; a horizontal electric field component at the target frequency value collected by the detection electrode is acquired by a detection host every first preset time interval; then an electric potential curve diagram is obtained through the horizontal electric field component, a profile pseudo-section diagram is obtained based on the electric potential curve diagram, and whether an anomaly appears underground in the monitoring area is judged based on the profile pseudo-section diagram; the technical scheme no longer needs manual inspection to find whether a geological anomaly appears in the dam, and whether a geological anomaly appears in the dam can be found in time and accurately through a management personnel on duty monitoring terminal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dam monitoring, and particularly relates to a dam monitoring method and system based on the magnetotelluric method. BACKGROUND

[0002] As an important part of water conservancy projects, dams have made extremely important contributions to human production and national economic development. With the increase of the running time of the dam, and the influence of construction quality, adverse geological structure and other factors, the geological hazards of the dam are increasing, and if the geological conditions of the dam appear abnormal conditions (such as internal collapse, cracks, water seepage, piping and the like), it will cause great hidden dangers to the personal safety and property safety of the nearby people.

[0003] In order to ensure the normal and safe use of the dam, it is necessary to monitor the safety of the dam. The existing safety monitoring method for the dam is mainly artificial inspection, which is not only low in efficiency, but also depends on the experience of the inspection personnel, and cannot guarantee timely and accurate discovery of whether the dam has geological abnormalities, so the safety monitoring effect is poor. SUMMARY

[0004] The main purpose of the present application is to provide a dam monitoring method and system based on the magnetotelluric method, which aims to solve the problem that the existing artificial inspection method for the dam cannot guarantee timely and accurate discovery of whether the dam has geological abnormalities.

[0005] The technical scheme provided by the present application is as follows:

[0006] A dam monitoring method based on the magnetotelluric method is applied to a dam monitoring system based on the magnetotelluric method; the system comprises a detection host, a detection electrode and a monitoring terminal; the monitoring terminal and the detection electrode are both in communication connection with the detection host; the number of the detection electrodes is multiple; the method comprises:

[0007] Determining a monitoring area in the dam, wherein a plurality of detection points in the same straight line are arranged in the monitoring area, the plurality of detection points are distributed at equal intervals, the distance between adjacent detection points is a preset distance, the number of detection points is consistent with the number of detection electrodes, and one-to-one correspondence exists between them;

[0008] Determining a plurality of collection points based on the detection points in the monitoring area, wherein the midpoint between two adjacent detection points is a collection point;

[0009] Determining a target frequency value of the monitoring area by the detection host;

[0010] After all the detection electrodes are embedded in the corresponding detection points, the detection host acquires the horizontal electric field component at the target frequency value collected by the detection electrodes every first preset time interval.

[0011] obtaining, by the detection host, an electric potential curve at the target frequency value based on the horizontal electric field component at the target frequency value;

[0012] obtaining, by the detection host, a profile pseudo-section based on the electric potential curve, and judging whether an anomaly occurs in the underground of the monitoring area based on the profile pseudo-section;

[0013] when the anomaly occurs in the underground of the monitoring area, generating, by the detection host, a warning information, sending the warning information to the monitoring terminal, and displaying the warning information on the monitoring terminal.

[0014] Preferably, after all the detection electrodes are embedded in the corresponding detection points, the detection host acquires the horizontal electric field component at the target frequency value collected by the detection electrodes every first preset time length, including:

[0015] Let the harmonic factor be e -iωt to obtain the frequency domain electromagnetic field equation set:

[0016]

[0017]

[0018] In the formula, E is the electric field intensity of the monitoring area, H is the magnetic field intensity of the monitoring area; J s represents the field source term, μ0 is the magnetic permeability in vacuum, i is the imaginary unit, ω is the circular frequency, and σ is the conductivity of the monitoring area;

[0019] Taking the curl of both sides of formula (1) and substituting formula (2) to obtain the second-order vector Helmholtz equation satisfied by the electric field in the monitoring area:

[0020]

[0021] Let the field source term be 0, and apply the first type of boundary condition on the boundary to obtain formula (5), wherein the first type of boundary condition is shown in formula (4):

[0022]

[0023] nE=nE0, (5)

[0024] In the formula, n is the outer normal vector of the boundary grid, and E0 is the electric field response of the one-dimensional medium on the boundary.

[0025] Preferably, the detection host determines the target frequency value of the monitoring area, including:

[0026] determining a maximum detection depth by the detection host based on the elevation of the dam;

[0027] determining a target frequency value of the monitoring area by the detection host based on the maximum detection depth.

[0028] Preferably, the obtaining of the profile pseudo-section graph by the detection host based on the potential curve, and determining whether an anomaly occurs in the underground of the monitoring area based on the profile pseudo-section graph, comprises:

[0029] obtaining the profile pseudo-section graph by the detection host taking the horizontal electric field component along the extension direction of the detection point as the profile line of the profile pseudo-section graph, taking the apparent depth as the vertical coordinate of the profile pseudo-section graph, and taking the position of each collection point distributed along the extension direction of the detection point as the upper horizontal coordinate of the profile pseudo-section graph;

[0030] determining, by the detection host, whether there is a region with a potential greater than a first preset value in the profile pseudo-section graph;

[0031] if there is, determining, by the detection host, that an anomaly occurs in the underground of the monitoring area;

[0032] marking, by the detection host, the region with the potential greater than the first preset value in the profile pseudo-section graph as a high potential region.

[0033] Preferably, the obtaining of the profile pseudo-section graph by the detection host taking the horizontal electric field component along the extension direction of the detection point as the profile line of the profile pseudo-section graph, taking the apparent depth as the vertical coordinate of the profile pseudo-section graph, and taking the position of each collection point distributed along the extension direction of the detection point as the upper horizontal coordinate of the profile pseudo-section graph, further comprises:

[0034] determining, by the detection host, whether there is a region with a potential less than a second preset value in the profile pseudo-section graph, wherein the second preset value is less than the first preset value;

[0035] if there is, determining, by the detection host, that an anomaly occurs in the underground of the monitoring area;

[0036] marking, by the detection host, the region with the potential less than the second preset value in the profile pseudo-section graph as a low potential region.

[0037] Preferably, the obtaining of the profile pseudo-section graph by the detection host taking the horizontal electric field component along the extension direction of the detection point as the profile line of the profile pseudo-section graph, taking the apparent depth as the vertical coordinate of the profile pseudo-section graph, and taking the position of each collection point distributed along the extension direction of the detection point as the upper horizontal coordinate of the profile pseudo-section graph, further comprises:

[0038] judging, by the detection host, whether a first condition is met, wherein the first condition is that there is no region with a potential greater than a first preset value and no region with a potential less than a second preset value in the profile pseudo-section map;

[0039] If yes, determining, by the detection host, that no anomaly exists in the underground of the monitoring area.

[0040] Preferably, the profile pseudo-section map is obtained by taking the horizontal electric field component along the extension direction of the detection point as the profile line of the profile pseudo-section map, taking the depth as the vertical coordinate of the profile pseudo-section map, and taking the positions of the collection points distributed along the extension direction of the detection point as the upper horizontal coordinate of the profile pseudo-section map, and then further comprising:

[0041] marking, by the detection host, a region with a potential greater than a third preset value and less than the first preset value in the profile pseudo-section map as a first target region, wherein the third preset value is less than the first preset value and greater than the second preset value;

[0042] judging, by the detection host, whether a second condition is met, wherein the second condition is that the area of the same first target region in the profile pseudo-section map generated in the past second preset time period gradually increases over time, wherein the second preset time period is greater than the first preset time period;

[0043] If yes, determining, by the detection host, that an anomaly exists in the underground of the monitoring area;

[0044] If no, determining, by the detection host, that no anomaly exists in the underground of the monitoring area.

[0045] Preferably, the profile pseudo-section map is obtained by taking the horizontal electric field component along the extension direction of the detection point as the profile line of the profile pseudo-section map, taking the depth as the vertical coordinate of the profile pseudo-section map, and taking the positions of the collection points distributed along the extension direction of the detection point as the upper horizontal coordinate of the profile pseudo-section map, and then further comprising:

[0046] marking, by the detection host, a region with a potential less than a fourth preset value and greater than the second preset value in the profile pseudo-section map as a second target region, wherein the fourth preset value is greater than the second preset value and less than the third preset value;

[0047] judging, by the detection host, whether a third condition is met, wherein the third condition is that the area of the same second target region in the profile pseudo-section map generated in the past second preset time period gradually increases over time;

[0048] If yes, determining, by the detection host, that an anomaly exists in the underground of the monitoring area;

[0049] If not, the detection host determines that no abnormality occurs underground in the monitoring area.

[0050] Preferably, the detecting host marks an area in the cross-sectional pseudo-cross-sectional image whose potential is greater than a third preset value and less than the first preset value as a first target area, and then further comprises:

[0051] Determining whether a fourth condition is satisfied by the detection host, wherein the fourth condition is: the number of first target areas in the cross-sectional pseudo-section image is greater than a preset number;

[0052] If so, determining through the detection host that an abnormality occurs underground in the monitoring area;

[0053] If not, the detection host determines that no abnormality occurs underground in the monitoring area.

[0054] The present invention also proposes a dam monitoring system based on magnetotelluric method, which applies a dam monitoring method based on magnetotelluric method; the system includes a detection host, detection electrodes and a monitoring terminal; the monitoring terminal and the detection electrodes are both communicatively connected to the detection host; the number of the detection electrodes is multiple.

[0055] The above technical solution can achieve the following beneficial effects:

[0056] The present invention proposes a dam monitoring method based on magnetotelluric method, which can timely and accurately detect whether there are geological anomalies in the dam; first determine the monitoring area of ​​the dam and the target frequency value corresponding to the monitoring area; set a plurality of detection points in the same straight line in the monitoring area, and the midpoint between two adjacent detection points is the collection point, and then embed the detection electrode into the detection point; obtain the horizontal electric field component at the target frequency value collected by the detection electrode through the detection host every first preset time; then obtain the potential curve through the horizontal electric field component, obtain the cross-sectional pseudo-section diagram based on the potential curve, and judge whether there are abnormalities underground in the monitoring area based on the cross-sectional pseudo-section diagram; this technical solution no longer requires manual inspections to detect whether there are geological anomalies in the dam, and the monitoring terminal can be used by the management personnel on duty to detect whether there are geological anomalies in the dam in a timely and accurate manner, which greatly improves the effect of safety monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0058] Figure 1 A step flow chart of a first embodiment of a dam monitoring method based on the magnetotelluric method is provided. DETAILED DESCRIPTION

[0059] It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

[0060] A dam monitoring method and system based on the magnetotelluric method are provided.

[0061] As shown in the drawings, Figure 1 In a first embodiment of a dam monitoring method based on the magnetotelluric method provided by the present application, the dam monitoring method based on the magnetotelluric method is applied to a dam monitoring system based on the magnetotelluric method; the system includes a detection host, detection electrodes, and a monitoring terminal; the monitoring terminal and the detection electrodes are both communicatively connected to the detection host; the number of detection electrodes is multiple; the embodiment includes the following steps:

[0062] Step S110: determining a monitoring area in a dam, wherein a plurality of detection points on the same straight line are arranged in the monitoring area, the plurality of detection points are distributed at equal intervals, the distance between adjacent detection points is a preset distance, the number of detection points is consistent with the number of detection electrodes, and one-to-one correspondence exists between the detection points and the detection electrodes.

[0063] Specifically, a plurality of monitoring areas can be arranged in the same dam; in the embodiment, the preset distance is 5 meters; the detection electrodes are detected by the natural electromagnetic method of the earth.

[0064] Step S120: determining a plurality of collection points based on the detection points in the monitoring area, wherein the midpoint between two adjacent detection points is a collection point.

[0065] Step S130: determining a target frequency value of the monitoring area by the detection host.

[0066] Specifically, different detection frequencies can reflect the geological conditions of different underground depths, so it is necessary to determine the corresponding target frequency value according to the detection depth requirement of the monitoring area.

[0067] Step S140: after all the detection electrodes are embedded in the corresponding detection points, the detection host acquires the horizontal electric field component at the target frequency value collected by the detection electrodes every first preset time length (for example, 1 day).

[0068] Specifically, the detection electrodes collect the horizontal electric field component once every 1 day.

[0069] Step S150: obtaining an electric potential curve graph at the target frequency value based on the horizontal electric field component at the target frequency value by the detection host.

[0070] Step S160: obtaining a profile pseudo-section graph based on the potential curve by the detection host, and judging whether an abnormality occurs in the underground of the monitoring area based on the profile pseudo-section graph.

[0071] Specifically, when the profile pseudo-section graph has an area with excessively high or low potential, it is determined that an abnormality occurs in the underground of the monitoring area, and the area with excessively high or low potential corresponds to the position of the geological abnormality. Conversely, when the profile pseudo-section graph does not have an area with excessively high or low potential, it is determined that no abnormality occurs in the underground of the monitoring area.

[0072] Step S170: when an abnormality occurs in the underground of the monitoring area, generating an early warning information by the detection host, sending the early warning information to the monitoring terminal, and displaying the early warning information on the monitoring terminal.

[0073] The dam monitoring method based on the magnetotelluric method can timely and accurately find whether a geological abnormality occurs in the dam. The monitoring area of the dam and the target frequency value corresponding to the monitoring area are determined. A plurality of detection points in the same straight line are arranged in the monitoring area, the midpoint between two adjacent detection points is a collection point, and then a detection electrode is embedded in the detection point. The horizontal electric field component at the target frequency value collected by the detection electrode is obtained by the detection host every first preset time interval. Then, the potential curve is obtained based on the horizontal electric field component, the profile pseudo-section graph is obtained based on the potential curve, and whether an abnormality occurs in the underground of the monitoring area is judged based on the profile pseudo-section graph. The technical solution no longer needs manual inspection to find whether a geological abnormality occurs in the dam, and the management personnel can timely and accurately find whether a geological abnormality occurs in the dam by monitoring the terminal, which greatly improves the effect of safety monitoring.

[0074] In a second embodiment of the dam monitoring method based on the magnetotelluric method, based on the first embodiment, step S140 includes the following steps:

[0075] Step S210: let the harmonic factor be e -iωt to obtain the frequency domain electromagnetic field equation set:

[0076]

[0077] In the formula, E is the electric field intensity of the monitoring area, H is the magnetic field intensity of the monitoring area, J s represents the field source term, μ0 is the magnetic permeability in vacuum, i is the imaginary unit, ω is the circular frequency, and σ is the conductivity of the monitoring area.

[0078] Specifically, any electromagnetic problem satisfies the Maxwell equation set, and the above frequency domain electromagnetic field equation set is obtained.

[0079] Step S220: taking the divergence of both sides of formula (1), and substituting formula (2) to obtain a second-order vector Helmholtz equation satisfied by the electric field in the monitoring area:

[0080]

[0081] Specifically, in the practical application of frequency domain electromagnetic method, the observation frequency is generally less than 104Hz, so the displacement current can be ignored.

[0082] Step S230: setting the field source term to 0, and applying the first type of boundary condition on the boundary to obtain formula (5), wherein the first type of boundary condition is shown in formula (4):

[0083]

[0084] nE=nE0, (5)

[0085] In the formula, n is the outer normal vector of the boundary grid, and E0 is the electric field response of the one-dimensional medium on the boundary.

[0086] In a third embodiment of the dam monitoring method based on the magnetotelluric method provided by the application, based on the first embodiment, step S130 includes the following steps:

[0087] Step S310: determining, by the detection host, a maximum detection depth based on the elevation of the dam.

[0088] Step S320: determining, by the detection host, a target frequency value of the monitoring area based on the maximum detection depth.

[0089] Specifically, the greater the detection frequency, the shallower the corresponding detection depth; the smaller the detection frequency, the deeper the corresponding detection depth; therefore, the target frequency value of the monitoring area is determined based on the maximum detection depth of the monitoring area; in this embodiment, the target frequency value is 200Hz.

[0090] In a fourth embodiment of the dam monitoring method based on the magnetotelluric method provided by the application, based on the first embodiment, step S160 includes the following steps:

[0091] Step S410: taking, by the detection host, the horizontal electric field component along the extension direction of the detection point as the profile line of the profile pseudo-section graph, taking the apparent depth as the vertical coordinate of the profile pseudo-section graph, and taking the positions of the collection points distributed along the extension direction of the detection point as the upper horizontal coordinates of the profile pseudo-section graph to obtain the profile pseudo-section graph.

[0092] Step S420: determining, by the detection host, whether there is an area with an electric potential greater than a first preset value in the profile pseudo-section graph.

[0093] Step S430: determining, by the detection host, that an anomaly exists in the underground of the monitoring area if there is.

[0094] Step S440: marking, by the detection host, the area with the potential greater than the first preset value in the profile pseudo-section map as a high potential area.

[0095] Specifically, in the embodiment, the first preset value is 50 mV, and when the potential is greater than the first preset value, it indicates that the area is a geological anomaly area (a high potential area), and specifically, it can be a geological anomaly condition such as a cavity, an ant nest, or an internal collapse.

[0096] In a fifth embodiment of the dam monitoring method based on the magnetotelluric method, based on the fourth embodiment, after step S410, the following steps are further included:

[0097] Step S510: determining, by the detection host, whether there is an area with a potential less than a second preset value in the profile pseudo-section map, wherein the second preset value is less than the first preset value.

[0098] Step S520: determining, by the detection host, that an anomaly exists in the underground of the monitoring area if there is.

[0099] Step S530: marking, by the detection host, the area with the potential less than the second preset value in the profile pseudo-section map as a low potential area.

[0100] Specifically, in the embodiment, the second preset value is 10 mV, and when the potential is less than the second preset value, it indicates that the area is a geological anomaly area (a low potential area), and specifically, it can be a geological anomaly condition such as piping or water seepage.

[0101] In a sixth embodiment of the dam monitoring method based on the magnetotelluric method, based on the fourth embodiment, after step S410, the following steps are further included:

[0102] Step S610: determining, by the detection host, whether a first condition is met, wherein the first condition is that there is no area with a potential greater than the first preset value and no area with a potential less than the second preset value in the profile pseudo-section map.

[0103] If yes, step S620 is performed: determining, by the detection host, that no anomaly exists in the underground of the monitoring area.

[0104] Specifically, if there is neither an area with a potential greater than the first preset value nor an area with a potential less than the second preset value in the profile pseudo-section map, it indicates that there is neither a high potential area nor a low potential area in the profile pseudo-section map, and thus it is determined that no anomaly exists in the underground of the monitoring area.

[0105] In a seventh embodiment of the dam monitoring method based on the magnetotelluric method, based on the fifth embodiment, after step S410, the method further comprises the following steps:

[0106] Step S710: marking, by the detection host, an area with an electric potential greater than a third preset value (for example, 40 mV) and less than the first preset value in the profile pseudo-section map as a first target area, wherein the third preset value is less than the first preset value, and the third preset value is greater than the second preset value.

[0107] Specifically, the first target area here is a relatively high potential area that does not reach the abnormal standard, but still has a certain risk and needs to be continuously observed.

[0108] Step S720: determining, by the detection host, whether a second condition is met, wherein the second condition is that the area of the same first target area in the profile pseudo-section map generated in the past second preset time length (for example, 3 days) gradually increases over time, wherein the second preset time length is greater than the first preset time length.

[0109] Specifically, when the area of the same first target area in the profile pseudo-section map generated in the past second preset time length (for example, 3 days) gradually increases over time, it indicates that the relatively high potential area is increasing, which needs to be warned and handled in time; therefore, it is determined that an abnormality occurs underground in the monitoring area.

[0110] If yes, step S730 is performed: determining, by the detection host, that an abnormality occurs underground in the monitoring area.

[0111] If no, step S740 is performed: determining, by the detection host, that no abnormality occurs underground in the monitoring area.

[0112] In an eighth embodiment of the dam monitoring method based on the magnetotelluric method, based on the seventh embodiment, after step S410, the method further comprises the following steps:

[0113] Step S810: marking, by the detection host, an area with an electric potential less than a fourth preset value (for example, 20 mV) and greater than the second preset value in the profile pseudo-section map as a second target area, wherein the fourth preset value is greater than the second preset value, and the fourth preset value is less than the third preset value.

[0114] Specifically, the second target area here is a relatively low potential area that does not reach the abnormal standard, but still has a certain risk and needs to be continuously observed.

[0115] Step S820: judging whether a third condition is satisfied by the detection host, wherein the third condition is that the area of the same second target region in the profile pseudo-section map generated in the past second preset time duration increases over time.

[0116] Specifically, when the area of the same second target region in the profile pseudo-section map generated in the past second preset time duration (for example, 3 days) increases over time, it indicates that the relatively low potential region is increasing, and early warning and timely processing are required; therefore, it is determined that an anomaly occurs underground in the monitoring region.

[0117] If yes, step S830 is performed: determining that an anomaly occurs underground in the monitoring region by the detection host.

[0118] If no, step S840 is performed: determining that no anomaly occurs underground in the monitoring region by the detection host.

[0119] In a ninth embodiment of the dam monitoring method based on the magnetotelluric method, based on the seventh embodiment, after step S710, the following steps are further included:

[0120] Step S910: judging whether a fourth condition is satisfied by the detection host, wherein the fourth condition is that the number of the first target regions in the profile pseudo-section map is greater than a preset number (3).

[0121] Specifically, when the number of the first target regions in the profile pseudo-section map is greater than 3, it indicates that although no high potential anomaly region occurs, multiple relatively high potential regions that are easy to evolve into high potential anomaly regions exist underground at the same time, and early warning is required in this case; therefore, it is determined that an anomaly occurs underground in the monitoring region.

[0122] If yes, step S920 is performed: determining that an anomaly occurs underground in the monitoring region by the detection host.

[0123] If no, step S930 is performed: determining that no anomaly occurs underground in the monitoring region by the detection host.

[0124] In a tenth embodiment of the dam monitoring method based on the magnetotelluric method, based on the seventh embodiment, after step S710, the following steps are further included:

[0125] Step S1010: judging whether a fifth condition is satisfied by the detection host, wherein the fifth condition is that the number of the first target regions in the profile pseudo-section map generated in the past second preset time duration gradually increases over time.

[0126] Specifically, when the number of first target areas in the pseudo-section diagram generated within the second preset time period gradually increases with the passage of time, it means that although there are no high-potential areas at present, the number of relatively high-potential areas that are prone to evolve into high-potential abnormal areas is gradually increasing. In this case, an early warning is also needed to prevent the sudden appearance of multiple high-potential areas, so it is determined that an abnormality occurs underground in the monitoring area.

[0127] If so, execute step S1020: determine through the detection host whether an abnormality occurs underground in the monitoring area.

[0128] If not, execute step S1030: determine through the detection host that there is no abnormality underground in the monitoring area.

[0129] The present invention also proposes a dam monitoring system based on magnetotellurics, which applies a dam monitoring method based on magnetotellurics; the system includes a detection host, detection electrodes and a monitoring terminal; the monitoring terminal and the detection electrodes are both communicatively connected to the detection host; and the number of the detection electrodes is multiple.

[0130] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0131] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A dam monitoring method based on magnetotelluric method, characterized in that: Applicable to a dam monitoring system based on magnetotelluric method; the system includes a detection host, detection electrodes and a monitoring terminal; The monitoring terminal and the detection electrode are both communicatively connected to the detection host; The number of the detection electrodes is multiple; the method includes: Determine a monitoring area on the dam, wherein a plurality of detection points are set in the monitoring area and are located in the same straight line. The plurality of detection points are evenly spaced, and the distance between adjacent detection points is a preset distance. The number of detection points is consistent with the number of detection electrodes and corresponds one to one. Determining a plurality of collection points based on the detection points within the monitoring area, wherein the midpoint between two adjacent detection points is a collection point; Determine the target frequency value of the monitoring area by the detection host; After all the detection electrodes are embedded in the corresponding detection points, the horizontal electric field components at the target frequency value collected by the detection electrodes are obtained by the detection host at every first preset time period; Obtaining a potential curve graph at a target frequency value based on a horizontal electric field component at a target frequency value by the detection host; Obtaining a cross-sectional pseudo-section diagram based on the potential curve diagram by the detection host, and judging whether an abnormality occurs underground in the monitoring area based on the cross-sectional pseudo-section diagram; When an abnormality occurs underground in the monitoring area, an early warning message is generated by the detection host, and the early warning message is sent to the monitoring terminal, and the early warning message is displayed by the monitoring terminal.

2. A dam monitoring method based on magnetotelluric method according to claim 1, characterized in that: After all the detection electrodes are embedded in the corresponding detection points, obtaining the horizontal electric field components at the target frequency value collected by the detection electrodes through the detection host every first preset time period includes: Let the harmonic transformation factor be , to obtain the frequency domain electromagnetic field equations: ，（1） ，（2） Where, E is the electric field strength of the monitoring area, and H is the magnetic field strength of the monitoring area; represents the field source term, is the magnetic permeability in vacuum, i is the imaginary unit, is the circular frequency, is the conductivity of the monitoring area; Calculate the curl on both sides of formula (1) and substitute formula (2) to obtain the second-order vector Helmholtz equation satisfied by the electric field in the monitoring area: ，（3） Let the source term be 0 and impose the first-type boundary condition on the boundary to obtain formula (5), where the first-type boundary condition is as shown in formula (4): ，（4） ，（5） Where n is the outer normal vector of the boundary grid, is the electric field response of the one-dimensional medium on the boundary.

3. The dam monitoring method based on magnetotelluric method according to claim 1, characterized in that: The determining of the target frequency value of the monitoring area by the detection host includes: Determining the maximum detection depth based on the altitude of the dam by the detection host; The detection host determines a target frequency value of the monitoring area based on the maximum detection depth.

4. The dam monitoring method based on magnetotelluric method according to claim 1, characterized in that: The detecting host obtains a pseudo-section diagram based on the potential curve diagram, and determines whether an abnormality occurs underground in the monitoring area based on the pseudo-section diagram, including: The detection host uses the horizontal electric field component along the extension direction of the detection point as the section line of the cross-sectional pseudo-section diagram, the apparent depth as the vertical coordinate of the cross-sectional pseudo-section diagram, and the positions of each collection point distributed along the extension direction of the detection point as the upper horizontal coordinate of the cross-sectional pseudo-section diagram to obtain the cross-sectional pseudo-section diagram; Determining, by the detection host, whether there is an area in the cross-sectional pseudo-sectional view with a potential greater than a first preset value; If so, the detection host determines that an abnormality occurs underground in the monitoring area; The detection host marks the area in the cross-sectional pseudo-section image where the potential is greater than the first preset value as a high-potential area.

5. The dam monitoring method based on magnetotelluric method according to claim 4, characterized in that: The detection host uses the horizontal electric field component along the extension direction of the detection point as the section line of the cross-sectional pseudo-section diagram, uses the apparent depth as the vertical coordinate of the cross-sectional pseudo-section diagram, and uses the positions of each collection point distributed along the extension direction of the detection point as the upper horizontal coordinate of the cross-sectional pseudo-section diagram to obtain the cross-sectional pseudo-section diagram, and then further includes: Determining, by the detection host, whether there is an area in the cross-sectional pseudo-cross-sectional view with a potential less than a second preset value, wherein the second preset value is less than the first preset value; If so, the detection host determines that an abnormality occurs underground in the monitoring area; The detection host marks the area in the cross-sectional pseudo-section image where the potential is less than the second preset value as a low-potential area.

6. The dam monitoring method based on magnetotelluric method according to claim 5, characterized in that: The detection host uses the horizontal electric field component along the extension direction of the detection point as the section line of the cross-sectional pseudo-section diagram, uses the apparent depth as the vertical coordinate of the cross-sectional pseudo-section diagram, and uses the positions of each collection point distributed along the extension direction of the detection point as the upper horizontal coordinate of the cross-sectional pseudo-section diagram to obtain the cross-sectional pseudo-section diagram, and then further includes: Determining whether a first condition is met by the detection host, wherein the first condition is: there is no area with a potential greater than a first preset value in the cross-sectional pseudo-section diagram, and there is no area with a potential less than a second preset value; If so, the detection host determines that there is no abnormality underground in the monitoring area.

7. The dam monitoring method based on magnetotelluric method according to claim 5, characterized in that: The detection host uses the horizontal electric field component along the extension direction of the detection point as the section line of the cross-sectional pseudo-section diagram, uses the apparent depth as the vertical coordinate of the cross-sectional pseudo-section diagram, and uses the positions of each collection point distributed along the extension direction of the detection point as the upper horizontal coordinate of the cross-sectional pseudo-section diagram to obtain the cross-sectional pseudo-section diagram, and then further includes: Marking, by the detection host, an area in the cross-sectional pseudo-cross-sectional image where the potential is greater than a third preset value and less than the first preset value as a first target area, wherein the third preset value is less than the first preset value, and the third preset value is greater than the second preset value; Determining, by the detection host, whether a second condition is satisfied, wherein the second condition is that an area of ​​the same first target region in the pseudo-sectional view generated within a second preset time period gradually increases over time, wherein the second preset time period is greater than the first preset time period; If so, determining through the detection host that an abnormality occurs underground in the monitoring area; If not, the detection host determines that no abnormality occurs underground in the monitoring area.

8. The dam monitoring method based on magnetotelluric method according to claim 7, characterized in that: The detection host uses the horizontal electric field component along the extension direction of the detection point as the section line of the cross-sectional pseudo-section diagram, uses the apparent depth as the vertical coordinate of the cross-sectional pseudo-section diagram, and uses the positions of each collection point distributed along the extension direction of the detection point as the upper horizontal coordinate of the cross-sectional pseudo-section diagram to obtain the cross-sectional pseudo-section diagram, and then further includes: Marking, by the detection host, an area in the cross-sectional pseudo-cross-sectional image where the potential is less than a fourth preset value and greater than a second preset value as a second target area, wherein the fourth preset value is greater than the second preset value, and the fourth preset value is less than the third preset value; Determining whether a third condition is satisfied by the detection host, wherein the third condition is: the area of ​​the same second target region in the pseudo-sectional view generated within the past second preset time period gradually increases over time; If so, determining through the detection host that an abnormality occurs underground in the monitoring area; If not, the detection host determines that no abnormality occurs underground in the monitoring area.

9. The dam monitoring method based on magnetotelluric method according to claim 7, characterized in that: The detecting host marks an area in the cross-sectional pseudo-cross-sectional image whose potential is greater than a third preset value and less than the first preset value as a first target area, and then further comprises: Determining whether a fourth condition is satisfied by the detection host, wherein the fourth condition is: the number of first target areas in the cross-sectional pseudo-section image is greater than a preset number; If so, determining through the detection host that an abnormality occurs underground in the monitoring area; If not, the detection host determines that no abnormality occurs underground in the monitoring area.

10. A dam monitoring system based on magnetotelluric method, characterized in that: A dam monitoring method based on magnetotelluric method as described in any one of claims 1 to 9 is applied; the system includes a detection host, detection electrodes and a monitoring terminal; the monitoring terminal and the detection electrodes are both communicatively connected to the detection host; and the number of the detection electrodes is multiple.

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