Active and passive electro-magnetic coupling monitoring device and method

Abstract

The present invention discloses a monitoring device and method for active and passive electro-magnetic coupling, which integrates an electromagnetic receiving coil and an electrode, so that the electrode enhances the ability of the electromagnetic receiving coil to receive electromagnetic signals; when performing passive detection, the electrode and the electromagnetic receiving coil can simultaneously collect natural potential data and natural electromagnetic data for the same position, so as to achieve the consistency of the natural potential data and the natural electromagnetic data in time and space; when performing active detection, transient electromagnetic detection and direct current electrical detection can be performed successively at the same position, so that the two methods can be collected as synchronously as possible in time and space, and through the combination of the two, it is possible to achieve the expansion of the monitoring range and depth on the basis of the original electrical monitoring range, and because the electromagnetic receiving coil enhances the ability to receive electromagnetic signals, the susceptibility to environmental interference during transient electromagnetic monitoring is reduced, and finally the data grouting area is covered and accurate data can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of geological monitoring, and in particular is a monitoring device and method of active and passive electro-magnetic coupling. Background Art

[0002] Grouting is a common technology for disaster management. It injects slurry to fill the voids in the rock mass and enhance the strength, thereby improving the stability of the structure. The control of the grouting process is crucial, because improper grouting may cause damage to the surrounding rock mass and cause negative effects. Traditional grouting monitoring methods include: surface deformation observation, drilling and electrical monitoring. The surface deformation is greatly disturbed by external factors, and it is difficult to accurately reflect the actual effect of grouting. It can only monitor surface changes and cannot effectively detect the deformation of deep soil. The drilling process of the drilling method is highly destructive and costly. It can only provide local information and it is difficult to fully evaluate the grouting effect; and the time delay of drilling makes the feedback not timely enough, and real-time monitoring cannot be achieved. The electrical method can perform real-time monitoring, but the monitoring range of the electrical method is limited by the length of the survey line, which is generally 1 / 2 of the survey line length or even less, and it cannot monitor a large range in a small space. As a detection method sensitive to low-resistance bodies, the transient electromagnetic method is gradually being used in grouting monitoring. However, the transient electromagnetic method has a detection blind spot and cannot accurately judge the shallow grouting effect. At present, there is also a method of joint monitoring of multiple methods, but because each monitoring device is implemented independently, the observation systems of different monitoring methods cannot be completely consistent (that is, multiple detection methods cannot be synchronized in time and space. For example, electromagnetic detection is not performed simultaneously during electrical monitoring, which means that they cannot be consistent in time; or although both are detected at the same time, they cannot be consistent in space due to the different detection equipment used). As a result, there are already errors in data acquisition for different monitoring, which ultimately leads to errors in the results of multiple detection methods and the inability to improve detection accuracy.

[0003] Therefore, how to provide a new device and method that can couple and complement multiple detection methods, and collect the detection area as synchronously as possible in time and space, and ultimately effectively improve the detection accuracy, is the research direction required by the present invention. Summary of the invention

[0004] In response to the problems existing in the above-mentioned prior art, the present invention provides a monitoring device and method for active and passive electromagnetic-magnetic coupling, which can couple and complement multiple detection methods, and collect data as synchronously as possible in time and space when detecting the detection area, ultimately effectively improving the detection accuracy.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an active and passive electro-magnetic coupling monitoring device, including multiple electromagnetic coupling probes, a transmitting loop, a host No. 1, a host No. 2 and a remote monitoring and early warning platform;

[0006] The electromagnetic coupling probe comprises an electrode and an electromagnetic receiving coil, wherein the electrode is used to excite and receive potential signals, and the electromagnetic receiving coil is wound around the electrode axially and outside the electrode to receive electromagnetic signals; the transmitting loop is used to excite transient electromagnetic signals;

[0007] The host No. 1 is connected to the electrodes of multiple electromagnetic coupling probes through a line, and is used to energize a part of the electrodes to excite potential signals, and at the same time receive potential signals collected by another part; the host No. 2 is connected to the transmitting loop and the electromagnetic receiving coils of multiple electromagnetic coupling probes through a line, and is used to energize the transmitting loop to excite transient electromagnetic signals, and receive electromagnetic signals collected by each electromagnetic receiving coil; wherein the electrode serves as a reinforcing magnetic core of the electromagnetic receiving coil, and is used to enhance the electromagnetic signal collected by the electromagnetic receiving coil;

[0008] The remote monitoring and early warning platform is connected to host No. 1 and host No. 2, and is used to control host No. 1 and host No. 2 to work synchronously, and obtain the data fed back by host No. 1 and host No. 2 for analysis and processing, so as to realize the monitoring of the grouting area.

[0009] Furthermore, the plurality of electromagnetic coupling probes are arranged in a row with equal intervals.

[0010] Furthermore, host No. 1 is an electrical instrument, and host No. 2 is a transient electromagnetic instrument.

[0011] Furthermore, the transmitting loop is a rectangle, and the multiple electromagnetic coupling probes are all located inside the rectangle.

[0012] The working method of the above active and passive electro-magnetic coupling monitoring device comprises the following specific steps:

[0013] Step 1: Before the grouting operation officially begins, firstly, the monitoring device is arranged in the grouting area, and the length of the measuring line formed by a row of multiple electromagnetic coupling probes with equal spacing is determined to be L, the spacing between adjacent electromagnetic coupling probes is d, and the number of electromagnetic coupling probes is n, so as to ensure the comprehensiveness of monitoring coverage and the accuracy of data; at the same time, the length a and width b of the transient electromagnetic emission loop are determined, and the length a is greater than L; multiple electromagnetic coupling probes are placed inside the emission loop, and host No. 1, host No. 2 and the remote monitoring and early warning platform are connected;

[0014] Step 2, start the monitoring device. In the unexcited stage, the electrodes and electromagnetic receiving coils of each electromagnetic coupling probe perform passive field acquisition, wherein the electrodes collect natural potential data at different positions in the grouting area, namely, the natural potential method, and feed the collected data back to host No. 1, and the electromagnetic receiving coils collect natural electromagnetic data at different positions in the grouting area, namely, the natural electromagnetic method, and feed the collected data back to host No. 2. Host No. 1 and host No. 2 feed back the data collected each time in the unexcited stage to the remote monitoring and early warning platform;

[0015] Step 3: The remote monitoring and early warning platform processes the data collected in the unexcited stage in real time to determine whether there are any abnormalities in the natural potential data and natural electromagnetic data collected in the unexcited stage. If there are no abnormalities in the data collected each time, the collection and processing process of steps 2 and 3 is continued until the continuous collection time T is entered into step 4; if there are abnormalities in the data collected at a certain time, it is a primary warning, the collection process of step 2 is stopped and step 4 is directly entered;

[0016] Step 4, the monitoring device enters the excitation stage, the remote monitoring and early warning platform first controls host No. 2 to energize the transmitting loop to excite transient electromagnetic signals, at this time, the electromagnetic receiving coils of each electromagnetic coupling probe collect transient electromagnetic data and feed it back to host No. 2, then the remote monitoring and early warning platform controls host No. 1 to energize a part of the electrodes to excite potential signals, and at the same time receives the potential signals collected from another part, after completion, the data collected by host No. 1 and host No. 2 are transmitted to the remote monitoring and early warning platform, completing the collection process of the excitation stage and entering step five;

[0017] Step 5: The remote monitoring and early warning platform processes the data collected during the excitation stage in real time to determine whether there are any abnormalities in the DC potential data and transient electromagnetic data collected during the excitation stage. If there are no abnormalities during the excitation stage, continue with steps 2 and 3 to enter the next time T collection and processing process; if there are abnormalities during the excitation stage, directly enter step 6;

[0018] Step 6. If only the data collected during the excitation stage is abnormal, it is an intermediate warning, which reminds the staff to further check the grouting situation to determine whether it is necessary to stop grouting. If both the non-excitation stage and the excitation stage are abnormal, it is a high-level warning, which reminds the staff to stop grouting immediately.

[0019] Furthermore, in the excitation stage, the DC electrical method adopted by host No. 1 is a symmetrical quadrupole, specifically: A and B poles are supply electrodes, M and N poles are measuring electrodes, positive and negative electricity are supplied to A and B poles respectively, and M and N poles collect potential data for DC electrical method running electrode collection. The effective monitoring range of this method is 0~L / 2.

[0020] Furthermore, the process of the remote monitoring and early warning platform judging abnormalities of the data in the unstimulated stage is as follows:

[0021] The natural potential and natural magnetic method are passive field acquisition methods. When an abnormality occurs, the signal will be elevated, which is reflected as a signal greater than the normal signal. Therefore, the excitation factor A is defined as:

[0022]

[0023] Where, E is the natural potential data collected each time, H is the natural electromagnetic data collected each time, and m is the number of collections;

[0024] Before grouting in the grouting area, the natural potential data and natural electromagnetic data of the area are collected for multiple times, and the A value of each time is calculated using the above formula, and then the average value is calculated as the threshold;

[0025] Then, for each data collected during the unexcited stage, the A value of each collected data is calculated using the above formula and compared with the threshold. If the A value of a certain collected data is greater than the threshold, it is judged that the data is abnormal; otherwise, it is judged that the data is not abnormal.

[0026] Furthermore, the process of the remote monitoring and early warning platform judging abnormalities of the data in the excitation phase is as follows:

[0027] The potential data processing formula obtained by direct current method in the excitation stage is as follows:

[0028]

[0029] Among them, ρ DC is the apparent resistivity obtained by direct current method, K is the device coefficient, I DC is the supply current, ΔU is the potential difference, L AM , L AN , L MN The electrode spacings corresponding to AM, AN, and MN are respectively, DC It is the direct current method to detect depth;

[0030] The processing formula for transient electromagnetic data obtained by transient electromagnetic method in the excitation stage is as follows:

[0031]

[0032] Among them, ρ TEM is the apparent resistivity calculated by transient electromagnetic, μ0 is the vacuum permeability, I0 is the emission current of the transient electromagnetic emission loop, a is the emission loop length, b is the emission loop width, t TEM is the transient electromagnetic acquisition time, B TEM is the induced electromotive force corresponding to each acquisition moment, D TEM is the depth obtained by transient electromagnetic calculation;

[0033] Combining the detection advantages of DC method and transient electromagnetic method, since both methods obtain apparent resistivity information, we first DC and ρ TEM All are normalized, and then the transient electromagnetic shallow layer results are replaced by the electrical method results. The specific processing method is:

[0034] 1. First, normalize the apparent resistivity according to the following formula: N is the number of data;

[0035] 2. Let n1 be the number of DC method data, and n2 be the number of transient electromagnetic method data;

[0036] Then for (D TEM1 D TEM2 …D TEM n2), less than D DCmax The data is removed and merged into new depth information (D DC1 D DC2 …D DCn1 D TEMx …D TEMn2 ), the corresponding resistivity information is

[0037]

[0038] According to the resistivity information obtained above, a D-ρ curve is drawn and a threshold is set. If the resistivity in the non-grouting range is lower than the threshold, it is judged that the data is abnormal. Otherwise, it is judged that the data is not abnormal.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] 1. The present invention integrates the electromagnetic receiving coil and the electrode, and the electrode is located at the center of the electromagnetic receiving coil, so that the electrode serves as a reinforced magnetic core, thereby enhancing the ability of the electromagnetic receiving coil to receive electromagnetic signals; during passive detection (i.e., the unexcited stage), the electrode and the electromagnetic receiving coil can simultaneously collect natural potential data and natural electromagnetic data for the same position, thereby achieving consistency in time and space between the natural potential data and the natural electromagnetic data during passive field detection, thereby ensuring the accuracy of data acquisition.

[0041] 2. During active detection (i.e., the excitation stage), transient electromagnetic detection and direct current electrical detection can be performed successively at the same position. The two methods are collected as synchronously as possible in time and space through an integrated design, and the detection characteristics of the electrical method are used to complement the transient electromagnetic detection, thereby making up for the blind spots of electromagnetic detection. That is, there is a certain blind spot (10 to 20 m) in transient electromagnetic detection at a relatively close position, and the electrical detection depth is limited by the length of the survey line, which is generally 1 / 2 of the survey line length L. The present invention can expand the monitoring range and depth on the basis of the original electrical monitoring range through the combination of the two. In addition, since the electromagnetic receiving coil is enhanced in its ability to receive electromagnetic signals by the electrode, the susceptibility to environmental interference during transient electromagnetic monitoring is reduced, thereby ultimately achieving coverage of the data grouting area and obtaining accurate data.

[0042] 3. The present invention only needs one monitoring device to perform two passive field monitoring methods, namely natural electromagnetic method and natural potential method, and can also perform two active field monitoring methods, namely direct current method and transient electromagnetic method. The situation in the grouting area is judged by coupling the four monitoring methods, thereby effectively improving the accuracy of the monitoring data and ensuring that the grouting area achieves the desired grouting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a structural schematic diagram of the electromagnetic coupling probe in the present invention;

[0044] Figure 2 It is a schematic diagram of the layout of the monitoring device of the present invention;

[0045] Figure 3 It is a schematic diagram of the effective monitoring range after coupling the direct current method and the transient electromagnetic method according to the present invention.

[0046] In the figure: 1-electromagnetic coupling probe, 1-1, electrode, 1-2, electromagnetic receiving coil, 2-transmitting loop, 3-host No. 1, 4-remote monitoring and early warning platform, 5-host No. 2. DETAILED DESCRIPTION

[0047] The present invention will be further described below.

[0048] like Figure 2 As shown, an active and passive electro-magnetic coupling monitoring device includes a plurality of electromagnetic coupling probes, a transmitting loop, a host No. 1, a host No. 2 and a remote monitoring and early warning platform;

[0049] like Figure 1 As shown, the electromagnetic coupling probe includes an electrode and an electromagnetic receiving coil, the electrode is used to excite and receive potential signals, the electromagnetic receiving coil is wound around the electrode axially outside the electrode to receive electromagnetic signals; the transmitting loop is used to excite transient electromagnetic signals;

[0050] The host No. 1 is connected to the electrodes of multiple electromagnetic coupling probes through lines, and is used to energize a part of the electrodes to excite potential signals, and at the same time receive the potential signals collected by another part. The host No. 2 is connected to the transmitting loop and the electromagnetic receiving coils of multiple electromagnetic coupling probes through lines, and is used to energize the transmitting loop to excite transient electromagnetic signals, and receive the electromagnetic signals collected by each electromagnetic receiving coil; wherein the electrode serves as a reinforcing magnetic core of the electromagnetic receiving coil, and is used to enhance the electromagnetic signal collected by the electromagnetic receiving coil; the multiple electromagnetic coupling probes are arranged in a row and at equal intervals, the transmitting loop is a rectangle, and the multiple electromagnetic coupling probes are all inside the rectangle.

[0051] The remote monitoring and early warning platform is connected to host No. 1 and host No. 2, and is used to control host No. 1 and host No. 2 to work synchronously, and obtain the data fed back by host No. 1 and host No. 2 for analysis and processing, so as to realize the monitoring of the grouting area; host No. 1 is an electrical instrument, and host No. 2 is a transient electromagnetic instrument.

[0052] The working method of the active and passive electro-magnetic coupling monitoring device is as follows:

[0053] Step 1: Before the grouting operation officially begins, firstly, the monitoring device is arranged in the grouting area, and the length of the measuring line formed by a row of multiple electromagnetic coupling probes with equal spacing is determined to be L, the spacing between adjacent electromagnetic coupling probes is d, and the number of electromagnetic coupling probes is n, so as to ensure the comprehensiveness of monitoring coverage and the accuracy of data; at the same time, the length a and width b of the transient electromagnetic emission loop are determined, and the length a is greater than L; multiple electromagnetic coupling probes are placed inside the emission loop, and host No. 1, host No. 2 and the remote monitoring and early warning platform are connected;

[0054] Step 2, start the monitoring device. In the unexcited stage, the electrodes and electromagnetic receiving coils of each electromagnetic coupling probe perform passive field acquisition, wherein the electrodes collect natural potential data at different positions in the grouting area, namely, the natural potential method, and feed the collected data back to host No. 1, and the electromagnetic receiving coils collect natural electromagnetic data at different positions in the grouting area, namely, the natural electromagnetic method, and feed the collected data back to host No. 2. Host No. 1 and host No. 2 feed back the data collected each time in the unexcited stage to the remote monitoring and early warning platform;

[0055] Step 3: The remote monitoring and early warning platform processes the data collected in the unexcited stage in real time to determine whether there are abnormalities in the natural potential data and natural electromagnetic data collected in the unexcited stage. The specific process is as follows:

[0056] The natural potential and natural magnetic method are passive field acquisition methods. When an abnormality occurs, the signal will be elevated, which is reflected as a signal greater than the normal signal. Therefore, the excitation factor A is defined as:

[0057]

[0058] Where, E is the natural potential data collected each time, H is the natural electromagnetic data collected each time, and m is the number of collections;

[0059] Before grouting in the grouting area, the natural potential data and natural electromagnetic data of the area are collected for multiple times, and the A value of each time is calculated using the above formula, and then the average value is calculated as the threshold;

[0060] Then, for each data collected during the unexcited stage, the A value of each collected data is calculated using the above formula and compared with the threshold. If the A value of a certain collected data is greater than the threshold, it is judged that the data is abnormal; otherwise, it is judged that the data is not abnormal.

[0061] If there is no abnormality in the data collected each time, the collection and processing process of steps 2 and 3 will continue until the collection time T is continued and step 4 is entered; if there is an abnormality in the data collected at a certain time, it is a primary warning, the collection process of step 2 is stopped and step 4 is directly entered;

[0062] Step 4, the monitoring device enters the excitation stage, the remote monitoring and early warning platform first controls host No. 2 to energize the transmitting loop to excite transient electromagnetic signals, at this time, the electromagnetic receiving coils of each electromagnetic coupling probe collect transient electromagnetic data and feed it back to host No. 2, then the remote monitoring and early warning platform controls host No. 1 to energize a part of the electrodes to excite potential signals, and at the same time receives the potential signals collected from another part. The DC method used by host No. 1 in the excitation stage is a symmetrical quadrupole, specifically: A and B poles are supply electrodes, M and N poles are measuring electrodes, positive and negative electricity are supplied to A and B poles respectively, M and N poles collect potential data for DC method running pole collection, and the effective monitoring range of this method is 0~L / 2; after completion, the data collected by host No. 1 and host No. 2 are transmitted to the remote monitoring and early warning platform, completing an excitation stage collection process and entering step five;

[0063] Step 5: The remote monitoring and early warning platform processes the data collected during the excitation phase in real time to determine whether there are abnormalities in the DC potential data and transient electromagnetic data collected during the excitation phase. The specific process is as follows:

[0064] The potential data processing formula obtained by direct current method in the excitation stage is as follows:

[0065]

[0066]

[0067]

[0068] Among them, ρ DC is the apparent resistivity obtained by direct current method, K is the device coefficient, I DC is the supply current, ΔU is the potential difference, L AM , L AN , L MN The electrode spacings corresponding to AM, AN, and MN are respectively, DC It is the direct current method to detect depth;

[0069] The processing formula for transient electromagnetic data obtained by transient electromagnetic method in the excitation stage is as follows:

[0070]

[0071]

[0072] Among them, ρ TEM is the apparent resistivity calculated by transient electromagnetic, μ0 is the vacuum permeability, I0 is the emission current of the transient electromagnetic emission loop, a is the emission loop length, b is the emission loop width, t TEM is the transient electromagnetic acquisition time, B TEM is the induced electromotive force corresponding to each acquisition moment, D TEM is the depth obtained by transient electromagnetic calculation;

[0073] Combining the detection advantages of DC method and transient electromagnetic method, since both methods obtain apparent resistivity information, we first DC and ρ TEM All are normalized, and then the transient electromagnetic shallow layer results are replaced by the electrical method results. The specific processing method is:

[0074] 1. First, normalize the apparent resistivity according to the following formula: N is the number of data;

[0075] 2. Let n1 be the number of DC method data, and n2 be the number of transient electromagnetic method data;

[0076] Then for (D TEM1 D TEM2 …D TEM n2), less than D DCmax The data is removed and merged into new depth information (D DC1 D DC2 …D DCn1 D TEMx …D TEMn2 ), the corresponding resistivity information is

[0077]

[0078] Draw the D-ρ curve (i.e., depth-resistivity curve) based on the resistivity information obtained above, and set a threshold. In this embodiment, the threshold is set to 0.8 times By observing the curve, if the resistivity in the non-grouting range is lower than the threshold, it is judged that the data is abnormal, otherwise it is judged that the data is not abnormal.

[0079] If there is no abnormality in the excitation stage, continue with steps 2 and 3 to enter the next time T collection and processing process; if there is an abnormality in the excitation stage, directly enter step 6;

[0080] Step 6. If only the data collected during the excitation stage is abnormal, it is an intermediate warning, which reminds the staff to further check the grouting situation to determine whether it is necessary to stop grouting. If both the non-excitation stage and the excitation stage are abnormal, it is a high-level warning, which reminds the staff to stop grouting immediately.

[0081] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A monitoring device for active and passive electro-magnetic coupling, characterized in that: It includes multiple electromagnetic coupling probes, transmission loops, host No. 1, host No. 2 and a remote monitoring and early warning platform; The electromagnetic coupling probe comprises an electrode and an electromagnetic receiving coil, wherein the electrode is used to excite and receive potential signals, and the electromagnetic receiving coil is wound around the electrode axially and outside the electrode to receive electromagnetic signals; the transmitting loop is used to excite transient electromagnetic signals; The host No. 1 is connected to the electrodes of multiple electromagnetic coupling probes through a line, and is used to energize a part of the electrodes to excite potential signals, and at the same time receive potential signals collected by another part; the host No. 2 is connected to the transmitting loop and the electromagnetic receiving coils of multiple electromagnetic coupling probes through a line, and is used to energize the transmitting loop to excite transient electromagnetic signals, and receive electromagnetic signals collected by each electromagnetic receiving coil; wherein the electrode serves as a reinforcing magnetic core of the electromagnetic receiving coil, and is used to enhance the electromagnetic signal collected by the electromagnetic receiving coil; The remote monitoring and early warning platform is connected to host No. 1 and host No. 2, and is used to control host No. 1 and host No. 2 to work synchronously, and obtain the data fed back by host No. 1 and host No. 2 for analysis and processing, so as to realize the monitoring of the grouting area.

2. The active and passive electro-magnetic coupling monitoring device according to claim 1, characterized in that: A plurality of electromagnetic coupling probes are arranged in a row with equal intervals.

3. The active and passive electro-magnetic coupling monitoring device according to claim 1, characterized in that: The host No. 1 is an electrical instrument, and the host No. 2 is a transient electromagnetic instrument.

4. The active and passive electro-magnetic coupling monitoring device according to claim 1, characterized in that: The transmitting loop is rectangular, and the plurality of electromagnetic coupling probes are all located inside the rectangle.

5. A working method of the active and passive electro-magnetic coupling monitoring device according to any one of claims 1 to 4, characterized in that: The specific steps are: Step 1: Before the grouting operation officially begins, firstly, the monitoring device is arranged in the grouting area, and the length of the measuring line formed by a row of multiple electromagnetic coupling probes with equal spacing is determined to be L, the spacing between adjacent electromagnetic coupling probes is d, and the number of electromagnetic coupling probes is n, so as to ensure the comprehensiveness of monitoring coverage and the accuracy of data; at the same time, the length a and width b of the transient electromagnetic emission loop are determined, and the length a is greater than L; multiple electromagnetic coupling probes are placed inside the emission loop, and host No. 1, host No. 2 and the remote monitoring and early warning platform are connected; Step 2, start the monitoring device. In the unexcited stage, the electrodes and electromagnetic receiving coils of each electromagnetic coupling probe perform passive field acquisition, wherein the electrodes collect natural potential data at different positions in the grouting area and feed the collected data back to host No. 1, and the electromagnetic receiving coils collect natural electromagnetic data at different positions in the grouting area and feed the collected data back to host No.

2. Host No. 1 and host No. 2 feed back the data collected each time in the unexcited stage to the remote monitoring and early warning platform; Step 3: The remote monitoring and early warning platform processes the data collected in the unexcited stage in real time to determine whether there are any abnormalities in the natural potential data and natural electromagnetic data collected in the unexcited stage. If there are no abnormalities in the data collected each time, the collection and processing process of steps 2 and 3 is continued until the continuous collection time T is entered into step 4; if there are abnormalities in the data collected at a certain time, it is a primary warning, the collection process of step 2 is stopped and step 4 is directly entered; Step 4, the monitoring device enters the excitation stage, the remote monitoring and early warning platform first controls host No. 2 to energize the transmitting loop to excite transient electromagnetic signals, at this time, the electromagnetic receiving coils of each electromagnetic coupling probe collect transient electromagnetic data and feed it back to host No. 2, then the remote monitoring and early warning platform controls host No. 1 to energize a part of the electrodes to excite potential signals, and at the same time receives the potential signals collected from another part, after completion, the data collected by host No. 1 and host No. 2 are transmitted to the remote monitoring and early warning platform, completing the collection process of the excitation stage and entering step five; Step 5: The remote monitoring and early warning platform processes the data collected during the excitation stage in real time to determine whether there are any abnormalities in the DC potential data and transient electromagnetic data collected during the excitation stage. If there are no abnormalities during the excitation stage, continue with steps 2 and 3 to enter the next time T collection and processing process; if there are abnormalities during the excitation stage, directly enter step 6; Step 6. If only the data collected during the excitation stage is abnormal, it is an intermediate warning, which reminds the staff to further check the grouting situation to determine whether it is necessary to stop grouting. If both the non-excitation stage and the excitation stage are abnormal, it is a high-level warning, which reminds the staff to stop grouting immediately.

6. The working method according to claim 5, characterized in that: The DC method adopted by host No. 1 in the excitation stage is a symmetrical quadrupole, specifically: A and B poles are supply electrodes, M and N poles are measuring electrodes, positive and negative electricity are supplied to A and B poles respectively, M and N poles collect potential data for DC method running electrode collection, and the effective monitoring range of this method is 0~L / 2.

7. The working method according to claim 5, characterized in that: The process of the remote monitoring and early warning platform judging abnormalities of the data in the unstimulated stage is as follows: The natural potential and natural magnetic method are passive field acquisition methods. When an abnormality occurs, the signal will be elevated, which is reflected as a signal greater than the normal signal. Therefore, the excitation factor A is defined as: Where, E is the natural potential data collected each time, H is the natural electromagnetic data collected each time, and m is the number of collections; Before grouting in the grouting area, the natural potential data and natural electromagnetic data of the area are collected for multiple times, and the A value of each time is calculated using the above formula, and then the average value is calculated as the threshold; Then, for each data collected during the unexcited stage, the A value of each collected data is calculated using the above formula and compared with the threshold. If the A value of a certain collected data is greater than the threshold, it is judged that the data is abnormal; otherwise, it is judged that the data is not abnormal.

8. The working method according to claim 6, characterized in that: The process of the remote monitoring and early warning platform judging abnormalities of the data in the excitation phase is as follows: The potential data processing formula obtained by direct current method in the excitation stage is as follows: Among them, ρ DC is the apparent resistivity obtained by direct current method, K is the device coefficient, I DC is the supply current, ΔU is the potential difference, L AM , L AN , L MN The electrode spacings corresponding to AM, AN, and MN are respectively, DC It is the direct current method to detect depth; The processing formula for transient electromagnetic data obtained by transient electromagnetic method in the excitation stage is as follows: Among them, ρ TEM is the apparent resistivity calculated by transient electromagnetic, μ0 is the vacuum permeability, I0 is the emission current of the transient electromagnetic emission loop, a is the emission loop length, b is the emission loop width, t TEM is the transient electromagnetic acquisition time, B TEM is the induced electromotive force corresponding to each acquisition moment, D TEM is the depth obtained by transient electromagnetic calculation; Combining the detection advantages of DC method and transient electromagnetic method, since both methods obtain apparent resistivity information, we first DC and ρ TEM All are normalized, and then the transient electromagnetic shallow layer results are replaced by the electrical method results. The specific processing method is:

1. First, normalize the apparent resistivity according to the following formula: N is the number of data; 2. Let n1 be the number of DC method data, and n2 be the number of transient electromagnetic method data; Then for (D TEM1 D TEM2 …D TEM n2), less than D DCmax The data is removed and merged into new depth information (D DC1 D DC2 …D DCn1 D TEMx …D TEMn2 ), the corresponding resistivity information is According to the resistivity information obtained above, a D-ρ curve is drawn and a threshold is set. If the resistivity in the non-grouting range is lower than the threshold, it is judged that the data is abnormal. Otherwise, it is judged that the data is not abnormal.

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