Methods for Visualizing and Real-time Feedback of Dam Grouting Repair Process

Abstract

This invention relates to a method for visualizing the grouting repair process of dams and providing real-time feedback on its effects. Holes are drilled around the grouting holes as observation holes, and signal transmitting and receiving antennas are placed in different observation holes to transmit / receive geophysical signals. Geophysical signals are collected at each grouting stage. After each signal collection, the antenna height is moved to collect signals for the next grouting stage. Based on the changes in the elevation of the geophysical signal waveforms, the inversion results of each grouting stage are visualized, and the repair effect is evaluated based on characteristic indicators. Specifically, the filling effect of the grout on the target area is first determined based on the changes in the characteristic indicator values ​​of the current grouting stage. Then, the grouting effect of the previous grouting stage is quantitatively evaluated based on the magnitude of the characteristic indicator values ​​calculated for the previous grouting stage within the signal coverage area of ​​the current grouting stage. This invention enables visualization and real-time feedback of the effects of grouting repair at each grouting stage.

Description

Technical Field

[0001] This invention belongs to the field of engineering structure reinforcement, specifically involving real-time observation of the grouting repair process for hidden dangers in dam structures and real-time evaluation of the repair effect. Background Technology

[0002] Grouting can reinforce and repair the core material of dams, improving their continuity, impermeability, and strength. However, grouting is a concealed process involving continuous flow and change of the grout, invisible in the underground space. The deterioration zones in the clay core layer are unevenly distributed, and the degradation areas are randomly distributed; therefore, the flow and diffusion process of the grout during grouting repair is unknown. Traditional methods, such as visual inspection of the surface, borehole inspection, analysis of core material samples, on-site permeability testing, and analysis of grout volume and permeability changes, can provide limited verification of the grouting effect. However, the results obtained only pertain to the area around the grouting hole and cannot describe the spatial characteristics of grout penetration and diffusion repair between adjacent holes, nor can they assess the repair effect inside the dam.

[0003] Currently, based on laboratory numerical simulations, theoretical calculations, and visual observation experiments, the "elliptical diffusion" pattern of grout can be observed, but it differs significantly from the actual grouting process of the core wall of an engineering dam. Geophysical methods are mostly used for comparative analysis and evaluation of tomographic imaging results before and after grouting, but lack real-time visualization of grouting results and quantitative assessment of repair effects. Patent CN104330838A discloses a method for fine exploration of underground engineering sudden water inrush channels and evaluation of grouting sealing effects, utilizing a time-shifted inversion-based full-space three-dimensional resistivity trans-hole CT detection method to monitor the entire grouting sealing process. However, this patent only performs real-time visualization of the grouting area using 3D resistivity cross-hole CT monitoring at the leak location. For grouting across the entire dam section, visualization of each grouting stage needs to be considered along the grouting depth direction. Visualizing in stages, compared to deploying antennas for the entire process, results in less signal acquisition, shorter inversion calculation time, and higher efficiency in grouting visualization and real-time evaluation of grouting effects. Specifically, the depth direction can be used as a fourth dimension to achieve dynamic visualization of the CT results at the current grouting stage, and to combine the CT monitoring results from each grouting stage to create visualizations of the grouting process at different grouting elevations. Based on the visualization results, the grouting effect at each stage can be evaluated and fed back in real time. If the grouting effect at the current stage is unsatisfactory, the grouting area can be immediately re-grouted. This controls the grouting quality at each stage, improving the overall quality of the grouting area.

[0004] Therefore, to visually and dynamically present the grout flow and filling characteristics of each grouting stage and evaluate the repair effect, and to prevent grout from flowing into the through channels during the grouting stage, resulting in significant grout loss and excessive leakage, a method for visualizing the dam grouting repair process and providing real-time feedback on the effect is proposed. This method uses a simple on-site observation procedure and automatic data interpretation to dynamically display the grout penetration, diffusion, and filling characteristics of each grouting stage, as well as to evaluate the grouting repair effect, achieving real-time tracking and feedback of the grouting effect. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems existing in the prior art and provide a method for visualizing the grouting repair process and providing real-time feedback on the effects.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] A method for visualizing the grouting repair process and providing real-time feedback on its effects, comprising:

[0008] Holes were drilled around the grouting hole to serve as observation holes. Signal transmitting and receiving antennas were placed in different observation holes to transmit / receive geophysical signals.

[0009] Geophysical signals were collected at each grouting stage. After each geophysical signal collection, the antenna height was moved to collect geophysical signals for the next grouting stage. The geophysical methods used were electromagnetic wave method or seismic wave method.

[0010] The inversion results of each grouting stage are visualized based on geophysical signals, and the repair effect is evaluated based on characteristic indicators. Specifically, the filling effect of the grout on the target area is first determined based on the change of characteristic indicator values ​​in the current grouting stage, and then the grouting effect of the previous grouting stage is quantitatively evaluated based on the magnitude of the characteristic indicator values ​​calculated in the previous grouting stage within the signal coverage area of ​​the current grouting stage.

[0011] The characteristic indicators are wave velocity, attenuation, and a combined indicator that includes both wave velocity and attenuation.

[0012] In a preferred embodiment, the pre-drilled holes around the grouting holes are selected as observation holes; the observation holes are arranged diagonally relative to the grouting holes and pass through the identified diseased area;

[0013] When there are multiple rows of observation holes, the receiving antennas are arranged in an array.

[0014] In a preferred embodiment, a plastic tube with a sealed bottom and joint is inserted into the observation hole as a protective tube, and the antenna is placed in the protective tube;

[0015] The protective wall is made to adhere tightly to the hole wall by filling with water or sand, and then the antenna is placed inside the hole.

[0016] In a preferred embodiment, the signal coverage area of ​​a single signal acquisition includes at least the grouting area of ​​the previous grouting stage, the grouting area of ​​the current grouting stage, and the grouting area of ​​the next grouting stage.

[0017] As a preferred implementation, geophysical signals are collected during the grouting return process at each grouting stage, as well as during the preparation process for pulling out the grout pipe and raising the grouting pipe to the next elevation after the completion of the current grouting stage; preferably, geophysical signals are collected when grouting return begins after the grouting pressure or grouting flow rate of the current grouting stage reaches a preset threshold.

[0018] As a preferred implementation, the grouting process is measured using a multi-elevation-difference mode. When the receiving antenna is a single receiver, the transmitting antenna is fixed at a certain elevation, and the receiving antenna receives signals multiple times from bottom to top in the monitoring area according to a preset point interval. When the transmitting antenna moves to a fixed elevation according to the point interval, the receiving antenna receives signals multiple times from top to bottom in the monitoring area. When the receiving antenna is a single cable with multiple receivers, the receiving antenna is fixed to receive multiple ray signals, and the transmitting antenna moves according to the point interval.

[0019] As a preferred implementation, the joint index is defined as follows:

[0020]

[0021]

[0022] Among them, Z c D c For different combined indicators, v is the wave speed, α is the attenuation coefficient, and ω is the angular velocity.

[0023] As a preferred implementation method, for the electromagnetic wave method, the qualitative evaluation is as follows: after the grout fills the leakage channel, the wave velocity increases, and the attenuation coefficient and D... c The index value decreased; after the grouting grout filled the pores and loose areas, the wave velocity decreased, and the attenuation coefficient and D... c The indicator value increased;

[0024] For the seismic wave method, the qualitative evaluation is as follows: after the grout fills the leakage channels and pores, the wave velocity and Z... c The value increases, the attenuation coefficient and D c The value decreases; after the grouting grout fills the incompletely compacted area, the wave velocity and Z value decrease. c The value decreases, the attenuation coefficient and D c The value increased.

[0025] As a preferred implementation method, the way to quantitatively evaluate the repair effect of the previous grouting stage based on characteristic indicators is as follows:

[0026] For the electromagnetic wave method, the quantitative evaluation is as follows: when the electromagnetic wave velocity is greater than 0.12 m / ns, the attenuation coefficient is less than 0.12 Np × 10⁻⁶. -3 / m and D c When the index value is less than 2.0, the grouting effect is excellent; when the electromagnetic wave velocity is between [0.10, 0.12] m / ns, the attenuation coefficient is between [0.12, 0.25] Np×10 -3 / m and D c When the index value is between [2.0, 5.0], the grouting effect is moderate; when the electromagnetic wave velocity is less than 0.10 m / ns, the attenuation coefficient is greater than 0.25 Np × 10. -3 / m and D c When the index value is greater than 5.0, the grouting effect is poor;

[0027] For the seismic wave method, the quantitative evaluation is as follows: when the seismic wave velocity is greater than 1.2 km / s, the attenuation coefficient is less than 0.10 Np × 10⁻⁶. -3 / m and D c When the index value is less than 0.167, the grouting effect is excellent; when the seismic wave velocity is between [1.0, 1.2] km / s and the attenuation coefficient is between [0.10, 0.16] Np×10 -3 / m and D c When the index value is between [0.167, 0.32], the grouting effect is moderate; when the seismic wave velocity is less than 1.0 km / s, the attenuation coefficient is greater than 0.16 Np × 10. -3 / m and D c When the index value is greater than 0.32, the grouting effect is poor.

[0028] As a preferred implementation, if the filling effect of the current grouting stage does not achieve the expected effect, the current stage is re-grouted. After the filling result of the current grouting stage achieves the expected effect, the grouting effect of the previous stage is quantitatively evaluated. If the quantitative result does not achieve the expected effect, re-grouting is performed through other grouting holes for repair.

[0029] The present invention has the following beneficial effects:

[0030] (1) Based on the operation process of dam grouting repair, an embeddable visualization monitoring method and monitoring scheme were designed. Without affecting the normal grouting operation, by arranging reasonable observation holes, signal acquisition modes and monitoring methods, signals are collected at appropriate time stages, and signals are automatically extracted and quickly inverted, so that the grouting effect of each grouting stage in the grouting process can be visualized in real time. The high-resolution characteristics of the results can effectively show the filling space characteristics of the grout in the current area.

[0031] (2) During the signal acquisition process, a reasonable signal coverage area is designed, and grouting judgment criteria and repair effect evaluation standards are designed by combining single evaluation indicators and newly designed joint evaluation indicators. This enables the determination of whether the grout has filled the target area in the current grouting stage; and based on the magnitude of multiple evaluation indicators of the signals acquired in the previous grouting stage when the signals are acquired in the current grouting stage, a quantitative evaluation of the grouting repair effect after the grout has solidified for a period of time in the previous stage is achieved. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of real-time monitoring of the dam grouting process, where: 1.1 is the grouting hole; 1.2 is the hidden danger area of ​​the grouting repair target; 1.3 is the transmitting antenna; 1.4 is the multi-channel receiving antenna; and 1.5 is the planar survey line of multiple monitoring profiles.

[0033] Figure 2 A flowchart for visual monitoring of the grouting stage in the grouting repair process.

[0034] Figure 3 A schematic diagram showing the arrangement of grouting holes and inspection holes on the grouting operation platform.

[0035] Figure 4 This is a schematic diagram of the automatic extraction of the initial arrival time and amplitude of the signal.

[0036] Figure 5 This is a schematic diagram showing the signal acquisition coverage area and the distribution of borehole survey lines during the grouting stage.

[0037] Figure 6 A diagram showing the visualization and monitoring process of a single grouting stage.

[0038] Figure 7 This is a visualization of the grouting process monitoring results for the entire grouting section of the dam. Detailed Implementation

[0039] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0040] Example 1

[0041] This embodiment provides a method for visualizing the grouting repair process and providing real-time feedback on the results. Based on the current grouting repair operation process, it embeds visual monitoring without affecting the original grouting process.

[0042] The steps of the visualization method for the grouting process are as follows:

[0043] First, in the grouting operation area, according to the number of rows of holes, the spacing between holes and the grouting process designed, at least two observation holes are arranged around the grouting holes.

[0044] Preferably, the holes drilled around the grouting hole are used as observation holes for the grouting process.

[0045] Preferably, the observation holes are arranged diagonally opposite to the grouting holes, passing through the identified diseased area.

[0046] A plastic tube with a sealed bottom and joint is inserted into the observation hole as a protective wall tube. Then, the protective tube is well coupled to the hole wall (the protective tube should fit snugly against the hole wall; this can be achieved by filling with water or sand). A real-time observation device (antenna) is then placed inside the hole. Based on geophysical exploration methods (in this embodiment, either the electromagnetic wave method or the seismic wave method is selected), a transmitting antenna is placed in one hole, and receiving antennas are placed in other suitable holes to transmit and receive signals.

[0047] In this embodiment, the geophysical method selected is either the electromagnetic wave method or the seismic wave method; seismic waves and radar measurements are fast and can quickly visualize the stage grouting even when coordinates change.

[0048] When there are multiple rows of observation holes, the receiving antennas are arranged in an array and receive signals through multiple channels. That is, the signals transmitted back by each receiving antenna in multiple rows of observation holes are received simultaneously, so as to realize the signal reception of multiple profiles in the grouting process.

[0049] The grouting process employs a multi-elevation-difference mode (where the transmitting antenna transmits a signal at a certain elevation, and the receiving antenna receives signals multiple times at different elevations) for measurement, conducting the transmission and reception of multiple ray signals to form a signal grid-like coverage area. Based on the grouting elevation at each stage of the grouting process, a visualization area for single monitoring is designed, namely the signal coverage area of ​​the transmitting and receiving antennas (the range of antenna movement within the borehole). Then, the movement points of the transmitting and receiving antennas within the borehole are designed. When the transmitting antenna moves to a certain elevation, the receiving antenna receives signals multiple times within the single monitoring area according to the point points. The antenna signal transmission and reception design can form as follows: Figure 5 The grid area for the acquired signal is shown.

[0050] Preferably, when the receiving antenna is a single receiver, the transmitting antenna is fixed at a certain elevation, and the receiving antenna receives signals multiple times from bottom to top in the monitoring area according to a point-to-point ratio. Then, when the transmitting antenna moves to a fixed elevation according to the point-to-point ratio, the receiving antenna receives signals multiple times from top to bottom in the monitoring area. When the receiving antenna is designed as a single cable with multiple receivers, the receiving antenna is fixed to receive multiple ray signals, and the transmitting antenna moves according to a point-to-point ratio.

[0051] Preferably, the signal coverage area (monitoring visualization area) of a single grouting phase includes at least the grouting area of ​​the previous grouting phase, the grouting area of ​​the current grouting phase, and the grouting area of ​​the next grouting phase.

[0052] During the grouting process, including the grout return process at each stage and the preparation process for pulling out the grout pipe and raising it to the next elevation after the completion of the current grouting stage, signal coverage area data is collected and analyzed. This method avoids interfering with the next stage of grouting and provides real-time information on the grouting repair status of the current stage.

[0053] Preferably, signal acquisition of the signal coverage area is carried out simultaneously when the grouting pressure or grouting flow rate reaches the threshold during the current grouting stage and grouting return begins.

[0054] Within the signal acquisition system, an independent visualization window is established, containing a new spatial coordinate system. During signal acquisition at each grouting stage, the results of automatic analysis of each waveform are converted to the corresponding grouting elevation in three-dimensional space (typically at 3m intervals), enabling dynamic visualization of the CT inversion results for each grouting stage. Figure 6 As shown in the figure, G1-G4 represent the grouting height at each grouting stage. Finally, by combining the CT monitoring results of each grouting repair, a dynamic visual monitoring system along the grouting depth direction is formed for the entire grouting process, as shown below. Figure 7 As shown, most of the slurry has solidified at this point.

[0055] Preferably, an automatic extraction algorithm is used to extract the initial arrival time and amplitude, which are then input into the inversion model for calculation. The visualization results of the single signal coverage area between observation wells are output in real time, showing the flow and diffusion area of ​​grout during the grouting stage.

[0056] Finally, after all grouting stages of the entire grouting hole are completed, a full-hole segment signal acquisition is performed (i.e., data for the entire hole depth is acquired in one go). During the acquisition process for each grouting stage and the entire hole segment, the acquisition parameters remain unchanged.

[0057] During the grouting process, the repair effect is evaluated in real time based on characteristic indicators. First, the filling effect of the grout on the target area is determined based on the changes in the characteristic indicator values ​​of the current grouting stage. Then, the grouting effect of the previous grouting stage is quantitatively evaluated based on the magnitude of the characteristic indicator values ​​calculated in the previous grouting stage within the signal coverage area of ​​the current grouting stage.

[0058] Based on the design of the grouting evaluation method, we can add an extra stage of grouting on the basis of the designed grouting depth, so that the bottom of the monitoring range is one stage higher than the bottom of the grouting.

[0059] Based on catastrophe theory, the initial arrival time of transmitted and received signals is automatically extracted. Assuming rapid propagation of the signal in the medium, the signal path can be approximated by a ray. Then, the travel time T of the ray when the signal propagates in the stratum is a function of the slowness D and the geometric path X.

[0060] [T] = [V][X] (1)

[0061] [V] is a large sparse matrix, which is solved using an iterative inversion algorithm to obtain the velocity distribution of the signal coverage area.

[0062] The peak amplitude of the transmitted and received signals is automatically extracted using the maximum value function. It is assumed that the propagation in the signal medium can be approximated by rays, and the attenuation coefficient equation also satisfies the linear equation through logarithmic transformation.

[0063]

[0064] An iterative inversion algorithm is used to solve the problem and obtain the attenuation distribution of the signal coverage area.

[0065] For evaluation metrics, the preferred options are wave velocity and attenuation coefficient (the attenuation of signal strength from the transmitting antenna to the receiving antenna). Wave velocity is more sensitive to the identification of pores and non-compactness, while attenuation is more sensitive to leakage channels. However, using a single independent metric for different types of defects may lead to misjudgment. Therefore, we designed two joint metrics to achieve a more accurate evaluation of grouting effect.

[0066] The new evaluation indicators are calculated as follows:

[0067]

[0068]

[0069] Among them, Z c D c For different combined indicators, v is the wave speed, α is the attenuation coefficient, and ω is the angular velocity.

[0070] Four index values ​​were selected at different offset distances: wave velocity, attenuation coefficient, and Z. c D c Analysis involves comparing the magnitude of the current grouting stage index value obtained from the previous grouting stage with the magnitude of the current grouting stage regional index value to determine whether the target area has been repaired in the current grouting stage.

[0071] Qualitative evaluation selects wave velocity, attenuation, and Z. c and D c The changes in indicators are used to judge the grouting effect. The changes in indicators differ between the electromagnetic wave method and the seismic wave method. The grouting filling standards for different hidden dangers are shown in Table 1.

[0072] Table 1 Grouting and Filling Standards

[0073]

[0074]

[0075] When the electromagnetic wave method is selected, after the grout fills the leakage channel, the wave velocity increases, and the attenuation coefficient and D... c The index value decreases; when the grout fills the pores and loose areas, the wave velocity decreases, and the attenuation coefficient and D... c The indicator value increased;

[0076] When the seismic wave method is selected, after the grout fills the leakage channels and cavities, the wave velocity and Z-axis... c The value increases, the attenuation coefficient and D c The value decreases; when the grout fills the incompletely compacted area, the wave velocity and Z value decrease. c The value decreases, the attenuation coefficient and D c The value increased.

[0077] The changes in index values ​​at the current grouting stage determine the filling effect of the grout on the target area. If the qualitative results show that the current stage is unsatisfactory, the current grouting stage can be re-grouted. After the qualitative results are satisfactory, the grouting effect of the previous stage can be quantitatively evaluated. Quantitative evaluation requires a period of solidification after grouting, so it will be performed in the next stage. If the quantitative results are unsatisfactory, re-grouting can be performed through other grouting holes for repair.

[0078] Qualitative evaluation selects wave velocity, attenuation, and D. c The changes in indicators are used to judge the grouting effect. The changes in indicators differ between the electromagnetic wave method and the seismic wave method. The evaluation criteria for the grouting effect of hidden dangers are shown in Table 2.

[0079] Table 2 Evaluation of Grouting Effect in the Previous Grouting Stage

[0080]

[0081] When using the electromagnetic wave method, the electromagnetic wave velocity must be greater than 0.12 m / ns and the attenuation coefficient must be less than 0.12 Np × 10⁻⁶. -3 / m and D c When the index value is less than 2.0, the grouting effect is excellent; when the electromagnetic wave velocity is between [0.10, 0.12] m / ns, the attenuation coefficient is between [0.12, 0.25] Np×10 -3 / m and D c When the index value is between [2.0, 5.0], the grouting effect is moderate; when the electromagnetic wave velocity is less than 0.10 m / ns, the attenuation coefficient is greater than 0.25 Np × 10. -3 / m and D c When the index value is greater than 5.0, the grouting effect is poor;

[0082] When using the seismic wave method, the seismic wave velocity should be greater than 1.2 km / s and the attenuation coefficient should be less than 0.10 Np × 10⁻⁶. -3 / m and D cWhen the index value is less than 0.167, the grouting effect is excellent; when the seismic wave velocity is between [1.0, 1.2] km / s and the attenuation coefficient is between [0.10, 0.16] Np×10 -3 / m and D c When the index value is between [0.167, 0.32], the grouting effect is moderate; when the seismic wave velocity is less than 1.0 km / s, the attenuation coefficient is greater than 0.16 Np × 10. -3 / m and D c When the index value is greater than 0.32, the grouting effect is poor.

[0083] Example 2

[0084] like Figure 1 As shown, on the grouting operation platform of the dam, observation holes are arranged around the grouting hole 1.1. A transmitting antenna 1.3 is placed in one of the observation holes, and multiple receiving antennas 1.4 are placed in the other observation holes to observe multiple profiles 1.5 of the grouting process. Among them, the observation profile composed of the transmitting antenna and a single receiving antenna passes through the grouting target potential hazard area 1.2.

[0085] Based on the grouting elevation of each grouting step, a signal acquisition area three times the elevation of a single grouting step is designed, including the grouting area of ​​the previous stage, the current grouting area, and the grouting area of ​​the next stage. Figure 5 As shown. In the signal acquisition area, the transmitting antenna moves at a fixed point distance of 0.5m to transmit signals from a single signal transmission point, while the multi-channel receiving antenna is placed in a suitable position to cover the signal acquisition area and receive multiple X-ray signals.

[0086] During normal grouting operations, when the grouting pressure and flow rate reach the set thresholds, and grout return is initiated, signal acquisition of the corresponding signal coverage area for the current grouting stage begins. Rapid signal acquisition of the signal coverage area is achieved within the time frame between the end of grout return and the extraction of the retaining pipe and lifting of the grouting pipe according to the designed single grouting elevation.

[0087] During the signal acquisition process, such as Figure 4 As shown, when the host receives the waveform of the signal, it automatically extracts the initial arrival time and peak amplitude of the waveform using the abrupt change criterion and the maximum value function. A joint iterative inversion technique is then used to quickly calculate the inversion result of a single ray signal, which is projected onto the spatial coordinate system of the system's visualization window. Based on the elevation change of each ray signal, the grouting process at the current grouting stage is dynamically and visually monitored. Finally, based on the monitoring results of each grouting stage, dynamic and visual monitoring of the entire grouting process is achieved in the spatial coordinate system of the visualization window.

[0088] Example 3

[0089] like Figure 3 As shown, during the grouting process, the grouting process is observed using the holes to be grouted. The observation holes are arranged diagonally, and the observation profile passes through the potential hazard area of ​​the grouting target.

[0090] The observation hole is protected with a PVC pipe that is sealed at the bottom and joints, ensuring good coupling between the pipe walls. The transmitting and receiving antennas are then placed inside the observation hole. Figure 5 As shown, based on the current elevation of the grouting area, the transmitting and receiving antennas are placed at the bottom of the grouting area from the previous stage.

[0091] like Figure 2 As shown, when the normal grouting operation process reaches the return grouting operation process, as... Figure 5 As shown, according to the designed point configuration, the transmitting antenna moves to the signal transmission point and transmits signals multiple times, while the receiving antenna receives signals multiple times at each signal reception point from bottom to top. When the transmitting antenna moves to the next signal transmission point and transmits signals multiple times, the receiving antenna receives signals multiple times at each signal reception point from top to bottom. This process is repeated to achieve signal acquisition within the signal coverage area. The signal coverage area consists of the previous grouting area, the current grouting area, and the next grouting area.

[0092] During signal acquisition, the initial arrival time and peak amplitude of the waveform are automatically extracted for each acquired signal, such as... Figure 4 As shown. Then, an inversion iterative algorithm is used, such as... Figure 2 As shown, the signal coverage area during the current grouting stage is visualized in real time. Based on the inversion results, the velocity and attenuation coefficient values ​​at different offset distances are selected, and then the new index value Z is calculated based on formulas (3) and (4). c and D c .

[0093] Based on the current grouting stage velocity, attenuation coefficient, and new Z obtained in advance from the previous grouting stage... c D c The index values, as well as the current grouting stage velocity, attenuation coefficient, and new Z obtained at the current grouting stage. c D c The indicator values ​​are used to determine the current grouting stage. The judgment criteria are shown in Table 1.

[0094] When using the electromagnetic wave method, for leakage channels, the wave velocity increases after grout filling, and the attenuation coefficient and D... c The index value decreases; for pores and loose areas, the wave velocity decreases after grout filling, and the attenuation coefficient and D decrease. c The index values ​​have increased. When using the selected seismic wave method, the wave velocity and Z-axis after grout filling are considered for leakage channels and pores. c The value increases, the attenuation coefficient and D cThe value decreases; for non-dense slurry filling, the wave velocity and Z value decrease. c The value decreases, the attenuation coefficient and D c Value increased;

[0095] The index values ​​calculated from the previous grouting stage are used to evaluate the grouting effect of the previous grouting stage (after the grout has solidified for a period of time).

Claims

1. A method for visualizing the grouting repair process and providing real-time feedback on its effects, characterized in that, include: Holes were drilled around the grouting hole to serve as observation holes. Signal transmitting and receiving antennas were placed in different observation holes to transmit / receive geophysical signals. Geophysical signals were collected at each grouting stage. After each geophysical signal collection, the antenna height was moved to collect geophysical signals for the next grouting stage. The geophysical methods used were electromagnetic wave method or seismic wave method. The inversion results of each grouting stage are visualized based on geophysical signals, and the repair effect is evaluated based on characteristic indicators. Specifically, the filling effect of the grout on the target area is first determined based on the change of characteristic indicator values ​​in the current grouting stage, and then the grouting effect of the previous grouting stage is quantitatively evaluated based on the magnitude of the characteristic indicator values ​​calculated in the previous grouting stage within the signal coverage area of ​​the current grouting stage. The characteristic indicators are wave velocity, attenuation, and a combined indicator that includes both wave velocity and attenuation. The combined indicator is defined as follows: ； ； in, , For different joint indicators, Let α be the wave velocity, α be the attenuation coefficient, and ω be the angular velocity.

2. The method according to claim 1, characterized in that, Select the pre-drilled holes around the grouting holes as observation holes; the observation holes are arranged diagonally relative to the grouting holes and pass through the identified diseased area; When there are multiple rows of observation holes, the receiving antennas are arranged in an array.

3. The method according to claim 1, characterized in that, A plastic tube with its bottom and joint sealed is inserted into the observation hole as a protective tube, and the antenna is placed in the protective tube; The protective wall is made to adhere tightly to the hole wall by filling with water or sand, and then the antenna is placed inside the hole.

4. The method according to claim 1, characterized in that, The signal coverage area of ​​a single signal acquisition includes at least the grouting area of ​​the previous grouting stage, the grouting area of ​​the current grouting stage, and the grouting area of ​​the next grouting stage.

5. The method according to claim 1, characterized in that, Geophysical signals were collected during the grout return process at each grouting stage, as well as during the preparation process for pulling out the grout pipe and raising it to the next elevation after the completion of the current grouting stage.

6. The method according to claim 5, characterized in that, Geophysical signal acquisition is performed when the grouting pressure or grouting flow rate reaches a preset threshold and grouting begins to return.

7. The method according to claim 1, characterized in that, The grouting process employs a multi-elevation-difference measurement mode. When the receiving antenna is a single receiver, the transmitting antenna is fixed at a certain elevation, and the receiving antenna receives signals multiple times from bottom to top in the monitoring area according to a preset point interval. When the transmitting antenna moves to a fixed elevation according to the point interval, the receiving antenna receives signals multiple times from top to bottom in the monitoring area. When the receiving antenna is a single cable with multiple receivers, the receiving antenna is fixed to receive multiple ray signals, and the transmitting antenna moves according to the point interval.

8. The method according to claim 1, characterized in that, For the electromagnetic wave method, the qualitative evaluation is as follows: after the grout fills the leakage channel, the wave velocity increases, and the attenuation coefficient and D... c The index value decreased; after the grouting grout filled the pores and loose areas, the wave velocity decreased, and the attenuation coefficient and D... c The indicator value increased; For the seismic wave method, the qualitative evaluation is as follows: after the grout fills the leakage channels and pores, the wave velocity and Z... c The value increases, the attenuation coefficient and D c The value decreases; after the grouting grout fills the incompletely compacted area, the wave velocity and Z value decrease. c The value decreases, the attenuation coefficient and D c The value increased.

9. The method according to claim 1, characterized in that, The method for quantitatively evaluating the repair effect of the previous grouting stage based on characteristic indicators is as follows: For the electromagnetic wave method, the quantitative evaluation is as follows: when the electromagnetic wave velocity is greater than 0.12 m / ns, the attenuation coefficient is less than 0.12 Np×10. -3 / m and D c When the index value is less than 2.0, the grouting effect is excellent; when the electromagnetic wave velocity is between [0.10, 0.12] m / ns, the attenuation coefficient is between [0.12, 0.25] Np×10 -3 / m and D c When the index value is between [2.0, 5.0], the grouting effect is moderate; when the electromagnetic wave velocity is less than 0.10 m / ns, the attenuation coefficient is greater than 0.25 Np×10. -3 / m and D c When the index value is greater than 5.0, the grouting effect is poor; For the seismic wave method, the quantitative evaluation is as follows: when the seismic wave velocity is greater than 1.2 km / s, the attenuation coefficient is less than 0.10 Np×10. -3 / m and D c When the index value is less than 0.167, the grouting effect is excellent; when the seismic wave velocity is between [1.0, 1.2] km / s and the attenuation coefficient is between [0.10, 0.16] Np×10 -3 / m and D c When the index value is between [0.167, 0.32], the grouting effect is moderate; when the seismic wave velocity is less than 1.0 km / s, the attenuation coefficient is greater than 0.16 Np×10. -3 / m and D c When the index value is greater than 0.32, the grouting effect is poor.

10. The method according to claim 1, characterized in that, If the filling effect of the current grouting stage does not meet the expected results, the current stage is re-grouted. After the filling result of the current grouting stage meets the expected results, the grouting effect of the previous stage is quantitatively evaluated. If the quantitative results do not meet the expected results, re-grouting is carried out through other grouting holes for repair.

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