A system and method for evaluating the effect of grouting at a working face based on charge-induced polarization method

Abstract

This invention, in the field of geophysical electromagnetic exploration technology, discloses a system and method for evaluating the grouting effect at the working face based on the charge-induced polarization method. A power supply device and a receiving device are deployed around the grouting drill rod at the working face. The power supply device includes power supply electrodes that directly charge the water body. The receiving device includes multiple non-polarized electrodes uniformly distributed on the working face. The method includes: after the power supply current stabilizes, injecting a high-conductivity, high-polarization solution into the water body in front of the working face, and during the injection of grout into the water body in front of the working face, acquiring the electric field components received by the multiple non-polarized electrodes. For the data received at the same time, the distribution data of electrical parameters at the working face are calculated to determine the changes in the distribution of the water body in front of the working face, and to infer the grout migration and solidification process. By setting up power supply electrodes directly connected to the water body in front of the working face, observation data can be acquired in real time before and during grouting, realizing dynamic monitoring of the grouting effect during the grouting process.

Description

Technical Field

[0001] This invention relates to the field of geophysical electromagnetic exploration technology, specifically to a system and method for evaluating the grouting effect at the working face based on the charging-induced polarization method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Mudslides and water inrushes occur when tunnels pass through karst terrain, resulting in a sudden and large influx of water at the tunnel face, posing a significant threat to tunnel engineering. Grouting is a common method for controlling mudslides and water inrushes at the tunnel face. It involves injecting grout into water-bearing, fractured rock strata, karst caves, and fractured zones. After the grout solidifies and hardens, it stabilizes the strata and isolates the water source. The quality of grouting directly affects the treatment effect; therefore, scientific and effective methods for evaluating grouting effectiveness are crucial for guiding grouting parameters and ensuring construction quality.

[0004] Currently, there is a lack of quantitative evaluation methods for the grouting effect at tunnel faces. Verification is typically based on a small number of boreholes, which introduces uncertainty and may even increase the risk of disaster in complex environments. Mine face grouting faces similar challenges. The charging method and induced polarization method are commonly used geophysical electromagnetic exploration methods, often used for detecting water bodies in underground spaces. They have the potential to detect the distribution and migration characteristics of water bodies ahead of the tunnel face and evaluate the grouting effect. However, conventional charging and induced polarization methods struggle to obtain high-quality geophysical signal data in complex environments such as small tunnel exploration spaces, strong electromagnetic interference, and short acquisition times. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a system and method for evaluating the grouting effect at the tunnel face based on the charge-induced polarization method. By setting a power supply electrode directly connected to the water body in front of the tunnel face, observation data is acquired in real time before and during grouting. A non-logarithmically uniform pseudo-random signal is supplied to achieve simultaneous detection by the charge-induced polarization method. Dynamic monitoring of the grouting effect during the grouting process is achieved based on the apparent resistivity and apparent amplitude-frequency dual electrical parameters. Specifically, in this invention, the drill rod used for the power supply electrode is the same as the drill rod used for injecting the high-conductivity, high-polarization solution, but it is not the same as the drill rod used for injecting the grout; the two are independent of each other.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0007] A grouting effect evaluation system based on the charge-induced polarization method at the tunnel face includes: a power supply device and a receiving device arranged around the grouting drill rod at the tunnel face, and a data analysis device connected to the receiving device; wherein, the power supply device includes power supply electrodes that directly charge water; the receiving device includes multiple non-polarized electrodes uniformly arranged on the tunnel face; the data analysis device is configured as follows:

[0008] After directly charging the water body, the electric field components received by the plurality of non-polarized electrodes are obtained;

[0009] After injecting a highly conductive and highly polarizable solution into the water in front of the tunnel face, the electric field components received by the multiple non-polarizable electrodes are monitored in real time to obtain the electric field components after the received data no longer changes.

[0010] During the process of injecting slurry into the water in front of the tunnel face, the electric field components received by the multiple non-polarized electrodes are acquired in real time.

[0011] For the electric field component data received by the multiple non-polarized electrodes at the same time, the distribution data of electrical parameters of the tunnel face are calculated respectively. Potential data is obtained by charging the water body, and the apparent resistivity is calculated. At the same time, based on the excitation polarization effect, the apparent amplitude frequency parameter is extracted. According to the changes in the apparent resistivity and / or apparent amplitude frequency of the tunnel face at different times, the changes in the distribution of water body in front of the tunnel face are determined, thereby inferring the slurry migration and solidification process.

[0012] Furthermore, the power supply electrode is used to transmit multi-frequency pseudo-random signals, and the electrical parameters include apparent resistivity and / or apparent amplitude frequency.

[0013] Furthermore, the method for calculating the apparent resistivity distribution data of the tunnel face at a certain time and frequency is as follows:

[0014] Calculate the potential difference data between the infinity electrode and the first non-polarized electrode, as well as between the adjacent electrodes, and then superimpose the potential difference data to obtain the potential data at each non-polarized electrode.

[0015] Based on the potential data at each non-polarized electrode, interpolation is performed based on the spatial positional relationship of the multiple non-polarized electrodes to obtain potential distribution data at different frequencies on the tunnel face. Based on the potential distribution data, the potential gradient is calculated along the radial direction with the location of the power supply electrode as the center point to obtain the potential gradient distribution map corresponding to each frequency.

[0016] Calculate the apparent resistivity distribution data based on the potential gradient distribution map.

[0017] Furthermore, the method for calculating the apparent amplitude frequency distribution data of the working face at a certain moment is as follows:

[0018] Calculate the potential difference data between the infinity electrode and the first non-polarized electrode, as well as between the adjacent electrodes, and then superimpose the potential difference data to obtain the potential data at each non-polarized electrode.

[0019] Based on the potential data at each non-polarized electrode, interpolation is performed based on the spatial positional relationship of the multiple non-polarized electrodes to obtain potential distribution data at different frequencies on the tunnel face.

[0020] Multiple frequency pairs are set up. Based on the potential distribution data corresponding to each frequency, the potential gradient is calculated along the radial direction with the location of the power supply electrode as the center point, so as to obtain the potential gradient distribution map corresponding to each frequency.

[0021] The apparent amplitude frequency distribution data is calculated based on the potential gradient distribution map of the two frequencies in each frequency pair.

[0022] Furthermore, after obtaining the apparent resistivity distribution data or the apparent amplitude-frequency distribution data of the tunnel face, contour maps are also generated.

[0023] One or more embodiments provide a method for evaluating the grouting effect at the tunnel face based on the charge-induced polarization method, wherein a power supply device and a receiving device are arranged around the grouting drill rod at the tunnel face; wherein, the power supply device includes a power supply electrode that directly charges the water body; the receiving device includes a plurality of non-polarized electrodes uniformly arranged on the tunnel face; the method includes the following steps:

[0024] After directly charging the water body, the electric field components received by the plurality of non-polarized electrodes are obtained;

[0025] After injecting a highly conductive and highly polarizable solution into the water in front of the tunnel face, the electric field components received by the multiple non-polarizable electrodes are monitored in real time to obtain the electric field components after the received data no longer changes.

[0026] During the process of injecting slurry into the water in front of the tunnel face, the electric field components received by the multiple non-polarized electrodes are acquired in real time.

[0027] For the electric field component data received by the multiple non-polarized electrodes at the same time, the distribution data of electrical parameters of the tunnel face are calculated respectively. Potential data is obtained by charging the water body, and the apparent resistivity is calculated. At the same time, based on the excitation polarization effect, the apparent amplitude frequency parameter is extracted. According to the changes in the apparent resistivity and / or apparent amplitude frequency of the tunnel face at different times, the changes in the distribution of water body in front of the tunnel face are determined, thereby inferring the slurry migration and solidification process.

[0028] The power supply electrode is used to transmit multi-frequency pseudo-random signals, and the electrical parameters include apparent resistivity and / or apparent amplitude frequency.

[0029] Furthermore, the method for calculating the apparent resistivity distribution data of the tunnel face at a certain time and frequency is as follows:

[0030] Calculate the potential difference data between the infinity electrode and the first non-polarized electrode, as well as between the adjacent electrodes, and then superimpose the potential difference data to obtain the potential data at each non-polarized electrode.

[0031] Based on the potential data at each non-polarized electrode, interpolation is performed based on the spatial positional relationship of the multiple non-polarized electrodes to obtain potential distribution data and potential difference distribution data at different frequencies on the tunnel face. Based on the potential distribution data, the potential gradient is calculated along the radial direction with the location of the power supply electrode as the center point to obtain the potential gradient distribution map corresponding to each frequency.

[0032] Calculate the apparent resistivity distribution data based on the potential gradient distribution map.

[0033] Furthermore, the method for calculating the apparent amplitude frequency distribution data of the working face at a certain moment is as follows:

[0034] Calculate the potential difference data between the infinity electrode and the first non-polarized electrode, as well as between the adjacent electrodes, and then superimpose the potential difference data to obtain the potential data at each non-polarized electrode.

[0035] Based on the potential data at each non-polarized electrode, interpolation is performed based on the spatial positional relationship of the multiple non-polarized electrodes to obtain potential distribution data at different frequencies on the tunnel face.

[0036] Multiple frequency pairs are set up. Based on the potential distribution data corresponding to each frequency, the potential gradient is calculated along the radial direction with the location of the power supply electrode as the center point, so as to obtain the potential gradient distribution map corresponding to each frequency.

[0037] The apparent amplitude frequency distribution data is calculated based on the potential gradient distribution map of the two frequencies in each frequency pair.

[0038] Furthermore, after obtaining the apparent resistivity distribution data or the apparent amplitude-frequency distribution data of the tunnel face, contour maps are also generated.

[0039] The above one or more technical solutions have the following beneficial effects:

[0040] This application achieves dynamic monitoring of the grouting effect by setting up power supply electrodes that are directly connected to the water in front of the tunnel face, and acquiring observation data in real time before and during grouting.

[0041] By injecting a high-conductivity, high-polarization solution before grouting, the properties of the water body in front of the tunnel face are enhanced, making the electrical differences between the water body, surrounding rock, and grout more obvious. Based on the enhanced properties, the distribution changes of the water body can be identified during the grouting process, and then the spatiotemporal distribution of the grout can be inferred. This enables multi-dimensional monitoring and effect evaluation of the grouting process, which helps to guide the optimization of grouting parameters and ensure construction quality.

[0042] Using multi-frequency pseudo-random signals for charging, a single transmission can acquire massive amounts of electromagnetic responses from multiple frequencies, resulting in a large volume of electromagnetic data. This effectively improves the method's anti-interference capability and ensures the quality of data acquisition.

[0043] By employing power supply electrodes capable of emitting multi-frequency pseudo-random electrical signals, potential data at multiple frequencies can be obtained. Specifically, low-frequency data can be used to acquire apparent amplitude frequency data, while high-frequency data can be used to acquire apparent resistivity data. This allows for monitoring of water distribution based on the distribution changes of either of the two electrical parameters, or for cross-verification based on the two electrical parameters at each moment. In other words, it enables accurate determination of water distribution at each moment based on the charge-induced polarization method, and further allows for inference of grout migration and solidification characteristics during the grouting process based on the water distribution at each moment.

[0044] Meanwhile, the non-polarized electrode is fixed on the working face, so there is no need to move the electrode over time or during the measurement process. It is less restricted by site conditions and requires less manpower compared to traditional methods. Attached Figure Description

[0045] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0046] Figure 1 This is a schematic diagram of the tunnel grouting drill rod, power supply device, and receiving device in an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the power supply device for the working face in an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of the three-dimensional arrangement of the power supply device at the working face in an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of the pseudo-random waveform and spectrum of the transmitting (power supply) current in an embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram illustrating the calculation of potential difference, apparent resistivity, and apparent amplitude frequency parameters in an embodiment of the present invention;

[0051] Figure 6This is a flowchart of the method for evaluating the grouting effect at the working face in an embodiment of the present invention. Detailed Implementation

[0052] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0053] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0054] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0055] This embodiment discloses a grouting effect evaluation system for tunnel faces based on the charge-induced polarization method. It uses multi-frequency pseudo-random electrical signal transmission to directly charge the water body in front of the tunnel face through power supply electrodes. Non-polarized electrodes arranged on the tunnel face receive the electric field components before and during grouting. The system effectively suppresses noise from the massive amounts of electromagnetic response information collected at multiple main frequencies, acquiring apparent resistivity and apparent amplitude-frequency parameter information, and performing comprehensive analysis. Based on the mutually constrained and verified distribution data of the dual electrical parameters, it identifies the water body distribution characteristics before grouting, infers the grout migration and solidification characteristics during grouting, evaluates the grouting effect, guides grouting parameters, and ensures construction quality.

[0056] The system includes a power supply device, a receiving device, and a data processing device. The receiving device is connected to the data analysis device and transmits the received electric field information to the data analysis device.

[0057] like Figure 1 , Figure 2 and Figure 3 As shown, the power supply device includes a controllable power supply capable of emitting multi-source pseudo-random signals, a pair of power supply electrodes, and several wires. In this embodiment, the controllable power supply can emit pseudo-random signals with a main frequency of 20 and the power meets the requirements of the charging method. Of the pair of power supply electrodes, one power supply electrode (denoted as power supply electrode A) is directly connected to the water body in front of the working face and should correspond to the same water body as the grouting drill rod Z. The other power supply electrode (denoted as power supply electrode B) corresponds to the infinity electrode and is placed at a distance from the working face greater than the aquifer depth by 15 to 20 times and grounded (this distance can be regarded as infinity).

[0058] The multi-frequency pseudo-random signal has a bandwidth of 0.25Hz to 4096Hz, with 20 main frequency pseudo-random signals at frequencies of 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 12, 16, 32, 64, 128, 256, 512, 1024, 2048, and 4096Hz. It is generated based on the method provided in patent CN111505722B (patent title: A method and system for generating logarithmically non-uniform pseudo-random electromagnetic exploration signals), combined with actual geological conditions. The low-frequency encryption portion (0.25-16Hz) is mainly used for frequency domain excitation polarization detection, while the frequency portion (2-4096Hz) is mainly used for charging method detection. Different frequencies correspond to different penetration depths, reflecting the water depth. The amplitudes of the 20 main frequencies in the signal are relatively consistent.

[0059] The receiving device includes multiple non-polarized electrodes, an infinity electrode, and several wires. The multiple non-polarized electrodes are evenly distributed around the power supply electrode on the working face. In this embodiment, there are a total of 12 non-polarized electrodes, which are arranged on the working face in the form of measuring lines as required. Some of the non-polarized electrodes can be arranged on the sidewall near the working face and remain fixed during the data acquisition process. The infinity electrode of the non-polarized electrodes on the working face is placed at a depth greater than 15 to 20 times the aquifer depth and grounded, and the distance from the infinity electrode of the power supply is greater than 15 to 20 times the aquifer depth.

[0060] Potential difference data can be obtained based on the electric field information acquired from adjacent pairs of non-polarized electrodes. The acquisition equipment and the transmitting signal end are strictly synchronized in time. The potential difference data in this observation system has directionality, that is, it has a positive and a negative sign. By superimposing the potential difference data in sequence according to the positive and negative relationship, the potential data corresponding to different frequencies on the tunnel face can be obtained.

[0061] Those skilled in the art will understand that, considering the complex environment of the tunnel, some of the device's deployment parameters (such as electrode spacing, number of survey lines, etc.) can be adjusted within a reasonable range according to the site conditions.

[0062] In this embodiment, before performing the grouting work, in addition to inserting the grouting drill rod Z into the water in front of the tunnel face, another drill rod is also inserted. This drill rod is used to connect the power supply electrode A into the water in front of the tunnel face on the one hand, and on the other hand, it is used for the injection of a high-conductivity, high-polarization solution.

[0063] Based on the above system, this embodiment also provides a method for evaluating the grouting effect at the tunnel face, which is executed by a data analysis device, such as... Figure 6 As shown, the specific steps include:

[0064] Step 1: Directly charge the water body through the power supply electrode to obtain the electric field components received by the plurality of non-polarized electrodes.

[0065] Before performing grouting, the water body is directly charged, and the emission current and electric field data are continuously acquired and accurately recorded over time as background data.

[0066] Step 2: After injecting a high-conductivity, high-polarization solution into the water in front of the tunnel face, the electric field components received by the multiple non-polarized electrodes are acquired in real time until the received data no longer changes, and the electric field components after the received data no longer changes are acquired.

[0067] By injecting a highly conductive and highly polarizable solution, such as sodium chloride solution, into the water ahead of the tunnel face, the properties of the water ahead can be enhanced, for example, by reducing the apparent resistivity of the water, which helps in monitoring the distribution of the water ahead. The fact that the received data no longer changes indicates that the solution has diffused uniformly and reached a stable state. By observing the changes in the electrical parameters of the tunnel face during solution injection, the distribution of the water ahead of the tunnel face can be determined. By comparing this with the electrical data obtained in step 1, the extent of the water ahead before grouting is defined.

[0068] Specifically, at regular intervals, the electric field components received by multiple non-polarized electrodes at the current moment are acquired, and the potential difference between adjacent pairs of non-polarized electrodes is calculated. When the potential difference data between two adjacent pairs no longer change, it is considered that the solution has completely diffused.

[0069] Step 3: During the process of injecting slurry into the water in front of the tunnel face, the electric field components received by the multiple non-polarized electrodes are acquired in real time until the received data no longer changes.

[0070] Throughout steps 1-3 above, the observation parameters remain constant, and the power supply device continuously transmits multi-frequency pseudo-random signals, such as... Figure 4 As shown, those skilled in the art will understand that electric field data at multiple frequencies were acquired at each moment.

[0071] Step 4: Group the acquired electric field data according to time. For the electric field component data received by the multiple non-polarized electrodes at the same time, calculate the distribution data of the electrical parameters of the tunnel face. Based on the changes in the distribution data of the electrical parameters of the tunnel face at different times, determine the changes in the distribution of water in front of the tunnel face, and thus infer the slurry migration and solidification process.

[0072] The electrical parameters include apparent resistivity and / or apparent amplitude frequency.

[0073] The method for calculating the apparent resistivity distribution data of the tunnel face at a certain frequency at a certain moment is as follows:

[0074] (1) The acquired electric field data are grouped according to time. The acquired electric field data includes the data measured before the solution is added, all the data measured after the solution is added, and the data measured after the grouting starts. The electric field component data acquired at infinity at the same time and the multiple non-polarized electrodes are grouped together.

[0075] (2) For the electric field data acquired at each time point corresponding to each frequency, calculate the potential difference data between the infinity electrode and the first non-polarized electrode, as well as between adjacent electrodes. Specifically, the potential difference data between infinity and non-polarized electrode 1 is denoted as ΔU1, the potential difference between non-polarized electrode 2 and non-polarized electrode 1 is denoted as ΔU2, and so on, to obtain the potential difference data ΔU. i , i = 1, 2, 3, ..., 12. The potential at infinity is considered zero.

[0076] (3) Based on the potential difference data and its positive and negative relationship, the potential distribution data of the working face is obtained. Specifically, for the electric field data corresponding to each frequency acquired at each moment, the potential difference data ΔUi is superimposed to obtain the superimposed potential data at each non-polarized electrode. Then, based on the spatial position relationship of the multiple non-polarized electrodes, interpolation is performed to obtain the interpolated potential distribution data U of different frequencies of the working face.

[0077] (4) Based on the interpolated potential distribution data of the tunnel face, calculate the apparent resistivity distribution data of the tunnel face. Specifically, for example... Figure 5 As shown, with the power supply electrode A as the center point, along a certain radial direction, based on the interpolated potential data of the working face corresponding to 2 to 4096 Hz, the apparent resistivity data between neighboring points Mn, Mn+1 (n = 1, 2, 3... up to the working face boundary) with a point distance of unit length is calculated sequentially along this radial direction to obtain the apparent resistivity data in this radial direction.

[0078] The formula for calculating apparent resistivity is:

[0079]

[0080] Where, ρ s Let be the apparent resistivity, K be the device coefficient related to the positions of Mn and Mn+1, I be the supply current, and ΔU be the difference in interpolated potential between points Mn and Mn+1.

[0081] By calculating the apparent resistivity data in different radii, the apparent resistivity distribution data of the tunnel face at a certain time and frequency can be obtained.

[0082] The method for calculating the apparent frequency distribution data of the working face at a certain frequency at a certain moment is as follows:

[0083] Steps (1)-(4) are the same as the calculation method for apparent resistivity distribution data described above;

[0084] (5) Set multiple frequency pairs, and based on the potential distribution data corresponding to each frequency, calculate the potential gradient along the radial direction with the location of the power supply electrode A as the center point to obtain the potential gradient distribution map corresponding to each frequency; then calculate the apparent amplitude frequency distribution data F based on the potential gradient distribution maps of the two frequencies in each frequency pair. s Specifically, such as Figure 5 As shown, with the power supply electrode A as the center point, along a certain radial direction, using the potential distribution data of the above 8 frequencies (0.25Hz-4Hz, 0.5Hz-8Hz, 0.75Hz-12Hz, 1Hz-16Hz) as the main frequency pairs, the potential gradient data between neighboring points Mn, Mn+1 (n=1, 2, 3... up to the tunnel face boundary) with a distance of unit length is calculated sequentially along this radial direction to obtain the potential gradient data along this radial direction.

[0085] The calculation formula is:

[0086]

[0087] Where ΔV is the potential gradient, ΔU is the difference between the interpolated potentials of points Mn and Mn+1, Mn and Mn+1 are the distance between points Mn and Mn+1, which is numerically equal to the unit length, and I is the supply current.

[0088] Based on the above 4 frequency pairs and the potential gradient data corresponding to the 8 frequencies, the apparent amplitude frequency data of a certain frequency pair in the radial direction is calculated using the following formula:

[0089]

[0090] Among them, F s For the apparent amplitude frequency, ΔV(f) L-Grad ), ΔV(f H-Grad These are the potential gradients for the low-frequency and high-frequency pairs, representing four sets of frequencies.

[0091] By calculating the apparent frequency data in different radii, the apparent frequency distribution data of the working face at a certain moment can be obtained under a certain set of frequency pairs.

[0092] Step 5: Based on the apparent resistivity distribution data of the face at different times and frequencies obtained in Step 4, and / or the corresponding apparent amplitude frequency data of multiple frequency pairs at different times, evaluate the grouting effect based on the water distribution before and during grouting.

[0093] To facilitate the observation and evaluation of the grouting effect, this embodiment also generates contour maps based on apparent resistivity distribution data and apparent amplitude frequency data.

[0094] As mentioned above, water bodies can have their properties enhanced by injecting highly conductive and highly polarizable solutions, such as having a very low apparent resistivity. By observing the distribution changes of apparent resistivity or apparent amplitude frequency data, we can understand the distribution changes of the water body.

[0095] Apparent resistivity distribution data and apparent amplitude-frequency data can both be used to observe and evaluate the grouting effect. To make the evaluation results more accurate, these two parameters can be obtained simultaneously. That is, the apparent amplitude-frequency data is obtained using low-frequency data, and the apparent resistivity data is obtained using high-frequency data. The two electrical parameters are mutually verified to accurately determine the water distribution at each moment. Then, based on the water distribution at each moment, the grout migration characteristics and solidification characteristics during the grouting process can be inferred.

[0096] The above embodiments transmit multi-frequency pseudo-random electrical signals to the water body in front of the tunnel face, and use non-polarized electrodes to obtain the resistivity and amplitude-frequency parameters of the tunnel face before and during grouting. Based on the mutually constrained and verified dual electrical parameters, the distribution of electrical parameters is imaged to identify the water body distribution characteristics before grouting, and the grout migration and solidification characteristics during grouting are inferred from this. After grouting, the grouting effect is evaluated based on the results, which guides the grouting parameters, ensures construction quality, and promotes the transformation of tunnel grouting effect evaluation from the traditional "qualitative" and "empirical" to "quantitative" and "scientific".

[0097] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A grouting effect evaluation system for tunnel face based on the charge-induced polarization method, characterized in that, include: A power supply device and a receiving device are arranged around the grouting drill rod at the working face, and a data analysis device is connected to the receiving device; wherein, the power supply device includes a power supply electrode that directly charges the water body; the receiving device includes multiple non-polarizing electrodes evenly arranged on the working face; the data analysis device is configured as follows: After directly charging the water body, the electric field components received by the plurality of non-polarized electrodes are obtained; After injecting a highly conductive and highly polarizable solution into the water in front of the tunnel face, the electric field components received by the multiple non-polarizable electrodes are monitored in real time to obtain the electric field components after the received data no longer changes. During the process of injecting slurry into the water in front of the tunnel face, the electric field components received by the multiple non-polarized electrodes are acquired in real time. For the electric field component data received by the multiple non-polarized electrodes at the same time, the distribution data of electrical parameters of the tunnel face are calculated respectively. Potential data is obtained by charging the water body, and the apparent resistivity is calculated. At the same time, based on the excitation polarization effect, the apparent amplitude frequency parameter is extracted. According to the changes in the apparent resistivity and / or apparent amplitude frequency of the tunnel face at different times, the changes in the distribution of water body in front of the tunnel face are determined, thereby inferring the slurry migration and solidification process. The power supply electrode is used to transmit multi-frequency pseudo-random signals, and the electrical parameters include apparent resistivity and / or apparent amplitude frequency; The method for calculating the apparent resistivity distribution data of the tunnel face at a certain frequency at a certain moment is as follows: Calculate the potential difference data between the infinity electrode and the first non-polarized electrode, as well as between the adjacent electrodes, and then superimpose the potential difference data to obtain the potential data at each non-polarized electrode. Based on the potential data at each non-polarized electrode, interpolation is performed based on the spatial positional relationship of the multiple non-polarized electrodes to obtain potential distribution data and potential difference distribution data at different frequencies on the tunnel face; based on the potential distribution data, the potential gradient is calculated along the radial direction with the location of the power supply electrode as the center point to obtain the potential gradient distribution map corresponding to each frequency. Calculate the apparent resistivity distribution data based on the potential gradient distribution map.

2. The grouting effect evaluation system for the working face based on the charge-induced polarization method as described in claim 1, characterized in that, The method for calculating the apparent amplitude frequency distribution data of the working face at a certain moment is as follows: Calculate the potential difference data between the infinity electrode and the first non-polarized electrode, as well as between the adjacent electrodes, and then superimpose the potential difference data to obtain the potential data at each non-polarized electrode. Based on the potential data at each non-polarized electrode, interpolation is performed based on the spatial positional relationship of the multiple non-polarized electrodes to obtain potential distribution data at different frequencies on the tunnel face. Multiple frequency pairs are set up. Based on the potential distribution data corresponding to each frequency, the potential gradient is calculated along the radial direction with the location of the power supply electrode as the center point, so as to obtain the potential gradient distribution map corresponding to each frequency. The apparent frequency distribution data is calculated based on the potential gradient distribution map of the two frequencies in each frequency pair.

3. The grouting effect evaluation system for the working face based on the charge-induced polarization method as described in claim 1, characterized in that, After obtaining the apparent resistivity distribution data or the apparent amplitude-frequency distribution data of the tunnel face, contour maps are also generated.

4. A method for evaluating the grouting effect at the tunnel face based on the charge-induced polarization method, characterized in that, A power supply device and a receiving device are installed around the grouting drill rod at the working face; wherein, the power supply device includes a power supply electrode that directly charges the water body; the receiving device includes multiple non-polarized electrodes evenly distributed on the working face; the method includes the following steps: After directly charging the water body, the electric field components received by the plurality of non-polarized electrodes are obtained; After injecting a highly conductive and highly polarizable solution into the water in front of the tunnel face, the electric field components received by the multiple non-polarizable electrodes are monitored in real time to obtain the electric field components after the received data no longer changes. During the process of injecting slurry into the water in front of the tunnel face, the electric field components received by the multiple non-polarized electrodes are acquired in real time. For the electric field component data received by the multiple non-polarized electrodes at the same time, the distribution data of electrical parameters of the tunnel face are calculated respectively. Potential data is obtained by charging the water body, and the apparent resistivity is calculated. At the same time, based on the excitation polarization effect, the apparent amplitude frequency parameter is extracted. According to the changes in the apparent resistivity and / or apparent amplitude frequency of the tunnel face at different times, the changes in the distribution of water body in front of the tunnel face are determined, thereby inferring the slurry migration and solidification process. The power supply electrode is used to transmit multi-frequency pseudo-random signals, and the electrical parameters include apparent resistivity and / or apparent amplitude frequency; The method for calculating the apparent resistivity distribution data of the tunnel face at a certain frequency at a certain moment is as follows: Calculate the potential difference data between the infinity electrode and the first non-polarized electrode, as well as between the adjacent electrodes, and then superimpose the potential difference data to obtain the potential data at each non-polarized electrode. Based on the potential data at each non-polarized electrode, interpolation is performed based on the spatial positional relationship of the multiple non-polarized electrodes to obtain potential distribution data and potential difference distribution data at different frequencies on the tunnel face; based on the potential distribution data, the potential gradient is calculated along the radial direction with the location of the power supply electrode as the center point to obtain the potential gradient distribution map corresponding to each frequency. Calculate the apparent resistivity distribution data based on the potential gradient distribution map.

5. The method for evaluating the grouting effect at the working face based on the charge-induced polarization method as described in claim 4, characterized in that, The method for calculating the apparent amplitude frequency distribution data of the working face at a certain moment is as follows: Calculate the potential difference data between the infinity electrode and the first non-polarized electrode, as well as between the adjacent electrodes, and then superimpose the potential difference data to obtain the potential data at each non-polarized electrode. Based on the potential data at each non-polarized electrode, interpolation is performed based on the spatial positional relationship of the multiple non-polarized electrodes to obtain potential distribution data at different frequencies on the tunnel face. Multiple frequency pairs are set up. Based on the potential distribution data corresponding to each frequency, the potential gradient is calculated along the radial direction with the location of the power supply electrode as the center point, so as to obtain the potential gradient distribution map corresponding to each frequency. The apparent frequency distribution data is calculated based on the potential gradient distribution map of the two frequencies in each frequency pair.

6. The method for evaluating the grouting effect at the tunnel face based on the charge-induced polarization method as described in claim 4, characterized in that, After obtaining the apparent resistivity distribution data or the apparent amplitude-frequency distribution data of the tunnel face, contour maps are also generated.

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