Intelligent grouting method based on real-time permeability monitoring

Abstract

The invention relates to the technical field of intelligent grouting, in particular to an intelligent grouting method based on real-time permeability monitoring, which comprises the following steps: arranging a pressure monitoring array in a to-be-grouted area, and electrically connecting the pressure monitoring array with a controller; grouting is started, and the time when the grout reaches all the measuring points is obtained; the stratum permeability change condition is calculated; and dynamically adjusting grouting parameters according to the permeability change condition, wherein the grouting parameters comprise grouting pressure, a water-cement ratio and a cement particle size. According to the method, the grouting target is achieved most efficiently, most economically and most safely through the most appropriate grout, and the problems that in a traditional grouting technology, grouting is not uniform, the reinforcing effect is poor, and potential safety hazards are large are solved. And the grouting parameters are dynamically adjusted based on the change of the permeability, it is ensured that proper grout is injected, the construction quality and efficiency are improved, and intelligent development of the grouting technology is further promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent grouting, and in particular to an intelligent grouting method based on real-time permeability monitoring. Background Art

[0002] As one of the core technologies in the fields of geotechnical engineering and civil engineering, grouting technology is a method of mixing specific materials in a certain ratio to obtain slurry, and using the pressure generated by the grouting pump to forcibly inject the slurry into the pores or cracks of the target body (such as loose soil layers, rock cracks, concrete cracks, etc.). After the solidification reaction, it realizes the functions of foundation reinforcement, anti-seepage and leakage plugging, and structural reinforcement. It plays an irreplaceable role in various projects. For this reason, grouting technology, with its core advantage of "precisely improving medium performance", ensures the stability of the structure in foundation reinforcement and blocks the threat of water disasters in engineering anti-seepage, becoming a key means to ensure safety, improve quality and extend life in modern engineering construction.

[0003] Different strata have different permeabilities. Especially when the soil pore structure is uneven or the groundwater flow is unstable, the permeability of the stratum will change dynamically during the grouting construction process. Preliminary geological surveys at the beginning of construction can only provide a rough model. If the permeability of the stratum is not monitored in real time during the grouting construction process, excessive or insufficient grouting, blind construction, ineffective grouting, and waste of slurry will occur. In addition, for strata with different permeabilities, it is necessary to select appropriate grouting parameters for grouting. Inappropriate grouting parameters may cause slurry to be blocked at the grouting port, incomplete stratum reinforcement, poor reinforcement effect, or environmental damage such as hydraulic fracturing and ground uplift.

[0004] In the field of grouting construction technology, there has not yet been a solution that can monitor changes in stratum permeability in real time and dynamically adjust grouting parameters based on permeability changes. The existing technology lacks an intelligent control mechanism for permeability changes. Therefore, how to achieve real-time monitoring and parameter regulation during the grouting process to ensure the uniformity of grouting, the optimality of reinforcement, and the safety of construction is an important direction for the current development of grouting construction technology. Summary of the Invention

[0005] The purpose of the present invention is to address the shortcomings of the existing technology and propose an intelligent grouting method based on real-time permeability monitoring, using the most suitable slurry to achieve the grouting goal in the most efficient, economical and safest way. It aims to solve the problems of uneven grouting, poor reinforcement effect, and large safety hazards existing in traditional grouting technology. This method uses a pressure sensor to realize real-time monitoring of the permeability coefficient of the formation, and dynamically adjusts the grouting parameters based on the change of permeability to ensure the injection of suitable slurry, so as to improve construction quality and efficiency and further promote the intelligent development of grouting technology.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: An intelligent grouting method based on real-time permeability monitoring, comprising: Step 1: Arrange a pressure monitoring array with pressure sensors in the area to be grouting, wherein the pressure sensors are electrically connected to the controller; Step 2: Start grouting and obtain the time when the slurry reaches each measuring point; Step 3: Calculate the rate of change of the formation permeability coefficient; Step 4: Dynamically adjust the grouting parameters according to the rate of change of the permeability coefficient. The grouting parameters include grouting pressure, water-cement ratio, and cement particle size.

[0007] Furthermore, in the step 1, the pressure monitoring array is formed by arranging a pressure sensor every 10 cm in the area to be grouting, and the pressure sensor is an earth pressure cell.

[0008] Furthermore, in step 3, the specific process of calculating the rate of change of the formation permeability coefficient is as follows: Calculate the Equivalent permeability coefficient of each measuring point , the formula is as follows:

[0009] in, is the static pressure head of the slurry, is the viscosity of the slurry, is the density of the slurry, is the acceleration due to gravity, The slurry front reaches the The time of each measurement point, From the grouting port to the The path length of each measuring point on the diffusion main plane, the coordinates of the grouting port are , No. The coordinates of the measurement points are ; Calculate the average permeability of the entire area at that moment , the formula is as follows:

[0010] in, is the total number of measuring points through which the slurry flows at that moment; Calculate the rate of change of permeability coefficient , the formula is as follows:

[0011] in, is the difference between the permeability coefficient at this moment and the permeability coefficient at the previous moment; is the permeability coefficient at the previous moment.

[0012] Furthermore, in step 4, the method of dynamically adjusting the grouting parameters according to the rate of change of the permeability coefficient is: when When adjusting the grouting pressure; when When adjusting the water-cement ratio; when When adjusting the cement particle size; in, and They are respectively the first threshold and the second threshold of the permeability coefficient change rate preset by the system.

[0013] Furthermore, in step 4, the process of adjusting the grouting pressure is: Calculate recommended values ​​for grouting pressure , the formula is as follows:

[0014] in, is the base pressure of grouting; α is the experience adjustment factor; The controller updates and controls the grouting pump pressure to the recommended value in real time .

[0015] Furthermore, in step 4, the process of adjusting the water-cement ratio is as follows: Select the recommended combination of water-cement ratio , the formula is as follows:

[0016] in, Indicates the The water-cement ratio of the slurry corresponds to the center value of the applicable permeability interval; The controller performs flushing in sequence and changes the water-cement ratio of the slurry to the recommended combination Resume grouting operation.

[0017] Furthermore, in step 4, the process of adjusting the cement particle size is as follows: Recommended values ​​for selecting cement particle size , the formula is as follows:

[0018] in, Indicates the Each particle size grade corresponds to the center value of the adapted permeability interval; The controller performs flushing in sequence and changes the cement particle size of the slurry to the recommended value. , resume grouting action.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention utilizes high-precision pressure sensors to continuously monitor changes in the permeability coefficient of the stratum during the grouting construction process, and transmits the data to the controller in real time, effectively avoiding the common phenomena of excessive or insufficient grouting, blind construction, ineffective perfusion, and slurry waste in traditional grouting processes, providing data support for dynamic grouting, and ensuring precise control during the grouting process; at the same time, the controller automatically adjusts the grouting parameters (water-cement ratio, injection pressure, cement particle size) according to the changes in the permeability coefficient. The real-time feedback mechanism can ensure that the grouting operation can maintain the best operating state under various stratum conditions, flexibly respond to the needs of different permeability strata, achieve the best grouting effect, reduce human operation errors, and avoid the phenomena of slurry blockage at the grouting port, incomplete stratum reinforcement, poor reinforcement effect, etc. due to failure to adjust the response in time to changes in stratum conditions, thereby significantly improving construction quality and efficiency.

[0020] Combining real-time monitoring with dynamic adjustments during the grouting process creates a perfect closed-loop intelligent control system: monitor → analyze → judge → adjust → monitor again. Real-time monitoring of formation permeability and dynamic adjustment of grouting parameters during the grouting process are core manifestations of the refined, information-based, and intelligent development of modern geotechnical engineering. Rather than blindly filling a black box, it achieves precise, safe, and efficient formation transformation through a "dialogue" with the formation. DETAILED DESCRIPTION

[0021] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0022] In engineering grouting, the grouting parameters that affect slurry injectability include grouting pressure, water-cement ratio, cement particle size, and permeability coefficient. To verify the adaptability of slurry injection under different formation permeability conditions, orthogonal experiments were conducted. The relationships among grouting pressure, water-cement ratio, cement particle size, and permeability coefficient were examined. Orthogonal experiments using the controlled variable method determined the impact of individual factors on grouting effectiveness, allowing the selection of slurry with optimal grouting parameters for engineering grouting. The experiments revealed the relationship between the permeability coefficients of different formations and the grouting parameters. Grouting methods were scientifically optimized for different permeability formations, ensuring the optimal match between the grouting process, grouting parameters, and formation conditions, resulting in efficient and safe grouting.

[0023] The effects of four factors, namely cement particle size, water-cement ratio, grouting pressure and permeability coefficient, on injectability were selected, and a 4-factor 3-level controlled variable method experimental scheme was designed. The slurry diffusion distance and time of each experimental group were recorded (the cement type, water-cement ratio and grouting pressure can be determined according to the actual situation on site for the experiment).

[0024]

[0025] Test materials: formation sample with high permeability coefficient, formation sample with medium permeability coefficient, formation sample with low permeability coefficient, fine-grained cement, medium-grained cement, coarse-grained cement, and water.

[0026] The experimental steps are as follows: 1. Install the grouting pipe, constant pressure slurry supply module, soil pressure sensor, data collector (controller) and video equipment in place in sequence, pressurize each functional module to the working pressure, check the air tightness of each interface and pipeline, and proceed to the next step only after confirming that there is no leakage.

[0027] Second, fill the grouting pipe with a thickness of 15 cm evenly and layer by layer the prepared stratum samples with various different permeability coefficients. Tamp each layer by light vibration or tapping. Place soil pressure boxes at different depths from the pipe mouth and connect them to the data collector. Then initialize all pressure channels to zero to ensure accurate readings.

[0028] 3. Prepare cement according to the designed water-cement ratio. Place each group into the mixer and pre-mix at low speed for about 120 seconds, then switch to high speed and mix thoroughly for about 120 seconds until the mixture is uniform and free of particles.

[0029] 4. For pressure-stabilized grouting, start the air pressure source, adjust the pressure-stabilizing valve to the target grouting pressure to keep the system pressure constant, open the slurry storage tank outlet valve, and inject the slurry into the grouting pipe. During the grouting process, keep the video recording and data acquisition running synchronously to record the grouting time, pressure changes and slurry front position in real time.

[0030] 5. End grouting and export data. When the slurry reaches the observation mark (or fills the test tube), immediately close the outlet valve to stop grouting, export all raw data such as pressure-time and displacement, and back up the video data.

[0031] Experimental results show that in medium-to-high permeability formations (permeability coefficient greater than 0.3 cm / s), smooth slurry injection can be achieved by using fine-grained cement simply by increasing the water-cement ratio and grouting pressure appropriately. When permeability increases further (permeability coefficient greater than 0.4 cm / s), even with coarser-grained cement, stable injection can be achieved under conventional grouting pressures (≥0.1 MPa) and water-cement ratios (≥1.0). Slurries of different particle sizes exhibit varying sensitivities to permeability coefficients: fine-grained cement has slightly higher permeability requirements, requiring higher permeability coefficients for successful injection. Medium-grained cement, however, exhibits similarly good injection performance in medium-to-high permeability formations when combined with an appropriate water-cement ratio and pressure control.

[0032] The above experimental results confirm that the slurry particle size, water-cement ratio, and grouting pressure should be combined and matched according to the actual permeability of the formation to achieve optimized grouting efficiency and uniformity. This conclusion provides an important basis for the subsequent dynamic control of grouting parameters and slurry selection strategy. Based on the above experimental results, the present invention provides an intelligent grouting method based on real-time permeability monitoring, which provides a reasonable basis for adjusting grouting parameters at the construction site. Technicians can select the appropriate cement type, water-cement ratio, and injection pressure based on the real-time permeability coefficient, realize grouting construction adapted to local conditions, and ensure the optimization of reinforcement effect.

[0033] This embodiment provides an intelligent grouting method based on real-time permeability monitoring. This method obtains the slurry diffusion front time by deploying pressure sensors, inverts the formation permeability coefficient in real time, and triggers multi-level response strategies such as grouting pressure adjustment, water-cement ratio change, and cement particle size replacement in sequence according to its change amplitude, thereby achieving adaptive grouting control for different formation conditions. The automated system reduces errors caused by human operation, improves the accuracy of the grouting process, and can flexibly adjust the grouting strategy according to formation changes, ensuring efficient construction under complex geological conditions, thereby improving the construction efficiency and safety of the project. Specifically, it includes the following steps: Step 1: Arrange a pressure monitoring array with pressure sensors in the area to be grouting, and electrically connect the pressure sensors to the controller.

[0034] A pressure sensor is arranged every 10 cm on the grouting path as a pressure monitoring point, and a two-dimensional or three-dimensional pressure monitoring array grid is formed in the grouting area. Each pressure sensor is electrically connected to the controller through a signal line, and the acquisition frequency of the pressure sensor is not less than 1 Hz to ensure sufficient time resolution. At the beginning of grouting, the pressure monitoring array is synchronously started to start acquisition and record the pressure-time change curve of each measuring point. Preferably, the pressure sensor is a soil pressure box. Specifically, the controller includes a data processing unit and a control feedback module for realizing automatic control. The data processing unit can compare and analyze the permeability coefficient data obtained in real time with the pre-established "stratum permeability-grouting parameter" relationship database to identify the current soil permeability status; when the permeability coefficient is monitored to change and exceed the threshold, the control feedback module will automatically adjust the grouting parameters, such as grouting pressure, water-cement ratio, grouting rate, etc., to maintain the continuity and uniformity of slurry diffusion. At the same time, the controller is also equipped with a graphical visualization interface, allowing operators to view the pressure curve, permeability coefficient distribution diagram and current grouting parameters of each monitoring point in real time. When the permeability changes abnormally or the parameters exceed the limit, the system will issue an alarm signal and link the control feedback module to automatically correct the grouting plan, realizing the closed-loop control of "monitoring-identification-feedback-adjustment" to ensure that the grouting operation is always in the optimal working condition.

[0035] Step 2: Start grouting and collect the time when the slurry reaches each measuring point.

[0036] When the slurry front diffuses to a certain measuring point, the soil pressure cell at the measuring point will detect an obvious pressure mutation or slope change, so that the controller can collect the time when the slurry front reaches the measuring point, and then automatically identify the time when the slurry reaches each measuring point. The time of each measurement point is .

[0037] Step 3: Calculate the rate of change of the formation permeability coefficient.

[0038] Calculate the Equivalent permeability coefficient of each measuring point , the formula is as follows:

[0039] in, is the static pressure head of the slurry, is the viscosity of the slurry, is the density of the slurry, is the acceleration due to gravity, The slurry front reaches the The time of each measurement point, From the grouting port to the The path length of each measuring point on the diffusion main plane, the coordinates of the grouting port are , No. The coordinates of the measurement points are .

[0040] Further calculate the moment (the slurry front reaches the The average permeability of the whole area at the time of the measurement point , the formula is as follows:

[0041] in, is the total number of measurement points through which the slurry flows at that moment, i.e., the number of measurement points through which the slurry flows at that moment. measurement points.

[0042] Calculate the rate of change of permeability coefficient , the formula is as follows:

[0043] in, is the difference between the permeability coefficient at this moment and the permeability coefficient at the previous moment; is the permeability coefficient at the previous moment; The system refreshes every 30 seconds and the permeability coefficient at the previous moment Compare, calculate , and then calculate the rate of change of the permeability coefficient .

[0044] Step 4: Dynamically adjust the grouting parameters according to the rate of change of the permeability coefficient. The grouting parameters include grouting pressure, water-cement ratio, and cement particle size.

[0045] Specifically, when When the change is small, it means that the current formation permeability is basically stable. The slurry diffusion efficiency is reduced only due to the change of the local grouting channel. At this time, the grouting pressure of the grouting pump is adjusted by the controller to improve the slurry diffusion capacity. The process is as follows: Calculate recommended values ​​for grouting pressure , the formula is as follows:

[0046] in, is the base pressure of grouting; α It is an empirical adjustment factor, usually set in stages according to the working conditions or according to the slurry / formation type, and can be slowly adaptive; The controller updates and adjusts the grouting pump pressure to the recommended value in real time .

[0047] when When the change is moderate, it indicates that the slurry diffusion is limited and increasing the grouting pressure can no longer effectively promote the slurry diffusion. The controller executes the slurry change logic 1, which switches the slurry to a water-cement ratio combination that is more suitable for the current formation. The process is as follows: Select the recommended combination of water-cement ratio , the formula is as follows:

[0048] in, Indicates selecting the index that minimizes the absolute difference between the brackets ; Indicates the The water-cement ratio of the slurry corresponds to the center value of the applicable permeability range.

[0049] The controller finds the best match for the current permeability coefficient among all candidate water-cement ratio combinations The water-cement ratio combination is to reduce the water-cement ratio, perform flushing in sequence, and change the water-cement ratio of the slurry to the recommended combination. , resume grouting action, and synchronously calibrate pressure and flow control strategies to prevent pipe blockage or slurry leakage.

[0050] when When the value of the grouting pressure is drastic, it indicates that the permeability structure of the stratum has changed significantly (such as switching to a low permeability layer, interlayer, weathered zone, etc.). Adjusting the water-cement ratio and grouting pressure cannot meet the slurry diffusion requirements. At this time, the controller executes the slurry change logic 2, that is, changing the cement particle size grade to adapt to the new medium (that is, the new stratum permeability structure).

[0051] Recommended values ​​for selecting cement particle size , the formula is as follows:

[0052] in, Indicates selecting the index that minimizes the absolute difference between the brackets ; Indicates the Each particle size grade corresponds to the center value of the adapted permeability interval.

[0053] The controller finds the particle size that best matches the current permeability coefficient among all candidate particle size classes. The particle size grade is to reduce the cement particle size, and then flush and change the cement particle size of the slurry to the recommended value. , resume grouting action, and synchronously calibrate pressure and flow control strategies to prevent pipe blockage or slurry leakage.

[0054] in, and are the first and second thresholds of the permeability coefficient change rate preset by the system, respectively, for different grouting area formation conditions. and The value range is different.

[0055] More specifically, homogeneous fine sand / medium sand (river sand, coral sand, etc.): ≈5% to 10%, ≈15% to 25%; gravel sand, obvious interlayers or strong heterogeneity: ≈10% to 15%; ≈25% to 40%; Fracture / weathered rock and rapid fluctuation scenarios: ≈12% to 18%; ≈30% to 45%.

[0056] Furthermore, during the initial grouting phase, multiple storage tanks are prepared to store cement slurries with varying water-cement ratios and particle size distributions to accommodate the grouting needs of different permeable formations. Based on real-time permeability coefficient data and calculated permeability coefficient change rates, the controller automatically selects the tank containing slurry with the appropriate water-cement ratio and particle size distribution, injects the slurry, and adaptively adjusts the injection pressure to instantly match the slurry type with the grouting parameters, ensuring that the specific needs of different formations can be met during the grouting process.

[0057] Furthermore, fiber Bragg grating sensors have high sensitivity, resistance to electromagnetic interference and distributed deployment capabilities. They can be deployed at different depths and orientations to achieve continuous monitoring of the formation status within the grouting influence range. During the grouting construction process, fiber Bragg grating sensors can be deployed along the grouting path or key parts of the surrounding rock as strain monitoring nodes. The fiber Bragg grating sensors are electrically connected to the controller to monitor the formation micro-deformation, strain evolution and grouting disturbance response in real time, providing high-precision formation safety data, and thus accurately evaluating the safety level of the grouting process. Specifically, referring to the monitoring index system in the current "SL 265-2016 Technical Specifications for Safety Monitoring of Hydraulic Structures" and "GB 50330-2013 Technical Specifications for Building Slope Engineering", and combining the on-site working conditions and empirical parameters, the dynamic safety thresholds during grouting are set as follows: the strain rate per unit time does not exceed 100 με / h, the cumulative strain does not exceed 800 με, the displacement increment in the grouting area does not exceed 2 mm / 3 min, the strain gradient is controlled within 50 με / m, and the radius of the grouting disturbance range does not exceed 3 m (determined based on similar formation test results or engineering experience). When the controller detects that the actual value approaches or exceeds the preset safety range, it automatically triggers an alarm and suspends grouting operations. It also initiates data backtracking and anomaly identification processes, combining the spatial distribution of strain to identify potential risks such as uneven diffusion of the grouting front or excessive local structural response. Grouting parameters (including grouting pressure, water-cement ratio, and grouting rate) are then adjusted in real time to restore grouting stability. This effectively enhances the intelligence and safety of grouting operations, possesses strong engineering adaptability and promotional value, and further ensures optimal grouting diffusion. More specifically, when the controller receives monitoring data indicating an abnormally high or sudden increase in the formation strain change rate, it determines the risk of stress concentration, over-rapid grouting, or localized blockage. The controller then reduces grouting pressure or suspends grouting operations to avoid risks such as splitting, arching, or sand flow. When the controller receives monitoring data indicating insufficient strain response or slow diffusion in the grouting area, it increases grouting pressure or optimizes grouting parameters to improve grouting efficiency and coverage. The application of fiber grating sensors greatly ensures the stability, uniformity, and reinforcement effect of the grouting process, reduces human intervention, and significantly improves the real-time safety control capability of the grouting process, providing effective guarantees for refined grouting construction under complex geological conditions.

[0058] Although the present invention has been described using the above preferred embodiments, they are not intended to limit the scope of protection of the present invention. Any person skilled in the art who makes various changes and modifications to the above embodiments without departing from the spirit and scope of the present invention still fall within the scope of protection of the present invention.

Claims

1. An intelligent grouting method based on real-time permeability monitoring, characterized in that: include: Step 1: Arrange a pressure monitoring array with pressure sensors in the area to be grouting, wherein the pressure sensors are electrically connected to the controller; Step 2: Start grouting and obtain the time when the slurry reaches each measuring point; Step 3: Calculate the rate of change of the formation permeability coefficient; Step 4: Dynamically adjust grouting parameters according to the rate of change of permeability coefficient, including grouting pressure, water-cement ratio, and cement particle size; In step 3, the specific process of calculating the rate of change of the formation permeability coefficient is as follows: Calculate the Equivalent permeability coefficient of each measuring point , the formula is as follows: ； ； in, is the static pressure head of the slurry, is the viscosity of the slurry, is the density of the slurry, is the acceleration due to gravity, The slurry front reaches the The time of each measurement point, From the grouting port to the The path length of each measuring point on the diffusion main plane, the coordinates of the grouting port are , No. The coordinates of the measurement points are ; Calculate the average permeability of the entire area at that moment , the formula is as follows: ； in, is the total number of measuring points through which the slurry flows at that moment; Calculate the rate of change of permeability coefficient , the formula is as follows: ； ； in, is the difference between the permeability coefficient at this moment and the permeability coefficient at the previous moment; is the permeability coefficient at the previous moment.

2. The intelligent grouting method based on real-time permeability monitoring according to claim 1 is characterized in that: In the step 1, the pressure monitoring array is formed by arranging a pressure sensor every 10 cm in the area to be grouting, and the pressure sensor is an earth pressure cell.

3. The intelligent grouting method based on real-time permeability monitoring according to claim 1 is characterized in that: In step 4, the method of dynamically adjusting the grouting parameters according to the rate of change of the permeability coefficient is: when When adjusting the grouting pressure; when When adjusting the water-cement ratio; when When adjusting the cement particle size; in, and They are respectively the first threshold and the second threshold of the permeability coefficient change rate preset by the system.

4. The intelligent grouting method based on real-time permeability monitoring according to claim 3 is characterized in that: In step 4, the process of adjusting the grouting pressure is as follows: Calculate recommended values ​​for grouting pressure , the formula is as follows: ； in, is the base pressure of grouting; α is the experience adjustment factor; The controller updates and controls the grouting pump pressure to the recommended value in real time .

5. The intelligent grouting method based on real-time permeability monitoring according to claim 3 is characterized in that: In step 4, the process of adjusting the water-cement ratio is as follows: Select the recommended combination of water-cement ratio , the formula is as follows: ； in, Indicates the The water-cement ratio of the slurry corresponds to the center value of the applicable permeability interval; The controller performs flushing in sequence and changes the water-cement ratio of the slurry to the recommended combination , resume grouting action.

6. The intelligent grouting method based on real-time permeability monitoring according to claim 3 is characterized in that: In step 4, the process of adjusting the cement particle size is as follows: Recommended values ​​for selecting cement particle size , the formula is as follows: ； in, Indicates the Each particle size grade corresponds to the center value of the adapted permeability interval; The controller performs flushing in sequence and changes the cement particle size of the slurry to the recommended value. , resume grouting action.

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