A synchronous grouting automatic regulation and control system for a shield

Abstract

The application provides a synchronous grouting automatic control system for a shield. The automatic control system comprises a data acquisition and preprocessing module, a coupling correlation calculation module, a dynamic control module and an effect feedback and parameter optimization module. The data acquisition and preprocessing module is used for acquiring dynamic construction parameters and static design parameters in a shield construction process. The coupling correlation calculation module calculates a target grouting rate according to the acquired multi-source data, and then calculates a required driving pressure in combination with slurry rheological parameters and pipeline resistance, and finally generates a grouting pump control instruction within a safe pressure range. The dynamic control module adjusts the grouting flow according to the control instruction. The effect feedback and parameter optimization module iteratively corrects the system, so that the system gradually adapts to real stratum conditions. The application constructs a linkage system of the tunneling speed, the grouting rate and the grouting pressure, and can achieve the whole-process synchronous and collaborative control of the grouting operation and the shield tunneling.

Description

Technical Field

[0001] This invention relates to the field of intelligent assisted driving technology for tunnel boring machines (TBMs), and in particular to an automatic control system for synchronous grouting in TBMs. Background Technology

[0002] In modern tunnel construction, shield tunneling, as an advanced tunnel excavation technology, is widely used in infrastructure construction fields such as urban subways, highway tunnels, railway tunnels, and municipal utility tunnels. In urban underground space development, tunnels crossing rivers and seas, and deep-buried tunnel projects, shield tunneling has become an important construction method for underground tunnels due to its high construction efficiency, minimal surface disturbance, and good safety. During shield tunneling, after the shield tail separates from the tunnel lining segments, an annular gap is formed between the outer wall of the segments and the excavation contour. The synchronous grouting system needs to continuously inject cement-based grout or two-component grout into this annular gap, allowing the grout to quickly fill the gap to form support, restrict ground deformation, reduce surface settlement, ensure the stability of the tunnel structure, improve the waterproof performance of the tunnel structure, prevent groundwater from seeping into the tunnel, protect the tunnel lining structure, and extend the tunnel's service life. Therefore, synchronous grouting during shield tunneling plays a crucial role in the stability, waterproofing, and protection of the surrounding environment of the tunnel, making it a vital step.

[0003] As tunnel boring machines (TBMs) gradually enter complex construction environments such as high water pressure, deep burial, water-rich soft soil, fault fracture zones, karst, and soft-hard composite strata, the traditional synchronous grouting control method has gradually revealed its insufficient adaptability, mainly in the following aspects:

[0004] I. There is a significant lack of accuracy in the grouting volume measurement method. Existing shield tunneling machines generally use the "pump stroke counting conversion" method to calculate the grouting volume. That is, by counting the number of reciprocating strokes of the grouting pump piston, combined with the preset theoretical grouting volume per stroke (calculated from parameters such as pump cylinder diameter and stroke length), the total grouting volume is then converted. In actual construction, the theoretical value of this metering method deviates significantly from the actual grouting volume. On the one hand, the grouting pump is prone to "vacuuming" due to uneven sand content, changes in fluidity, and air leakage in the pipeline. In this case, although the piston completes its stroke, it does not effectively draw in and inject grout, and the stroke count will still include it in the effective grouting volume, resulting in an inflated measurement. On the other hand, when the grout flows in the pipeline, it will generate solidified cement blocks, frictional resistance, and local resistance. Furthermore, with changes in grouting pressure, factors such as wear of pump body seals and gaps in the inner wall of the cylinder will cause fluctuations between the actual grouting volume and the theoretical value for a single stroke. The stroke counting method cannot capture these dynamic changes and only uses a fixed theoretical value for calculation, further reducing the metering accuracy. Furthermore, the existing "pump stroke counting conversion" method can only count the cumulative grouting volume and cannot obtain the grouting volume data per unit time. Therefore, it cannot calculate the grouting speed (grouting volume per unit time) in real time, nor can it detect abnormal situations such as excessively fast, slow, or sudden changes in grouting speed in a timely manner. It cannot achieve real-time monitoring and feedback of grouting speed. As a key control parameter in synchronous grouting construction, grouting speed makes it difficult for operators to judge the construction status based on changes in grouting speed and to take timely control measures such as adjusting pump pressure and flow rate. This may lead to quality and safety hazards such as incomplete grout filling, excessive deformation of surrounding rock, and segment floating, directly affecting the grout diffusion range, consolidation effect, and surrounding rock stability. In addition, existing methods for measuring grout volume include ordinary flow meter measurement and mortar tank weighing. Ordinary flow meters are difficult to adapt to high-viscosity, non-continuously pumped mortar media and are prone to measurement distortion due to grout solidification and flow fluctuations. Mortar tank weighing is affected by factors such as construction vibration, trolley tilting, and complex multi-sensor data fusion, resulting in low reliability. These inaccurate grout volume data directly lead to a lack of precise basis for subsequent control and cannot guarantee the effective filling of the annulus behind the tunnel segment wall.

[0005] Second, achieving a precise match between tunneling speed and grouting rate is difficult. In actual construction, the tunneling speed of the tunnel boring machine (TBM) varies due to various factors such as geological conditions and equipment performance. If the grouting rate cannot be adjusted in time to keep pace with the tunneling speed, a faster tunneling speed coupled with a slower grouting rate can lead to insufficient grout filling of the tail gap, increasing the risk of ground subsidence. Conversely, a slower tunneling speed coupled with a faster grouting rate not only wastes grout but may also result in excessively high grouting pressure, adversely affecting the segment structure. Furthermore, the control of grouting pressure is not precise enough. Insufficient grouting pressure prevents the grout from effectively filling the tail gap, failing to achieve the desired grouting effect. Excessive grouting pressure can cause segment deformation, rupture, tail leakage, and even ground heave. Moreover, traditional grouting control methods often rely on manual experience, making it difficult to dynamically adjust the grouting rate and pressure in real time and accurately based on changes in tunneling speed and geological conditions, leading to unstable grouting quality and increased construction risks.

[0006] Third, the implementation of the dual control of "grouting volume + grouting pressure" in synchronous grouting is difficult. Since the core of synchronous grouting is to use the preset grouting volume (to ensure the filling volume) and grouting pressure (to control the diffusion range and avoid damage to the segments) as dual control indicators, it can theoretically take into account both the filling effect and construction safety. However, in actual application, due to the complexity of geology, equipment precision, parameter matching and other issues, there are many inherent shortcomings.

[0007] First, the compatibility between grouting volume and grouting pressure varies greatly under different geological conditions: in soft soil and water-rich strata, the grout diffuses rapidly, potentially resulting in a situation where "the grouting volume has reached the design value, but the pressure remains below the lower control limit" (severe grout leakage, failing to form effective support); in hard rock and strata with unevenly developed fractures, the situation may occur where "the pressure reaches the upper limit first, but the grouting volume is far from meeting the standard" (the grout is blocked by local fractures and cannot effectively fill the annulus). When indicators conflict, operators find it difficult to determine which indicator to follow, easily leading to improper control.

[0008] Secondly, the parameters are rigid and cannot adapt to dynamic geological conditions: the dual control indicators (grouting volume and pressure) are mostly fixed values ​​preset according to the design geological survey report, but the geological conditions (such as soil moisture content, porosity, and degree of fracture development) change dynamically during actual tunneling: if the preset value is too large, it will lead to grout waste and segment cracking under pressure; if the preset value is too small, it will lead to incomplete filling and deformation of the surrounding rock. Manual adjustment of parameters is lagging and cannot achieve real-time dynamic adaptation.

[0009] Third, there is a lack of linkage feedback mechanism and the response to anomalies is delayed: the existing dual control is mostly "independent monitoring and manual judgment", and there is no automatic linkage logic between quantity and pressure. When anomalies such as "quantity meets the standard but pressure is too low" (grout leakage) or "pressure meets the standard but quantity is insufficient" (pipe blockage) occur, the early warning cannot be triggered in time. Operators need to manually analyze the data and adjust the equipment. The delayed response can easily lead to quality and safety hazards.

[0010] In summary, existing shield tunneling synchronous grouting technology has significant shortcomings in terms of tunneling speed, grouting rate, and pressure control. Its synchronous grouting control method struggles to precisely match tunneling speed with grouting rate and pressure, resulting in poor grouting effects and impacting tunnel construction quality and safety. This fails to meet the high precision, high efficiency, and high safety requirements of modern tunnel construction. Therefore, developing a system capable of automatically controlling the coupling of tunneling speed, grouting rate, and pressure is of great significance and engineering application value for improving shield tunneling construction quality, ensuring project safety, and promoting the development of tunnel construction technology. Summary of the Invention

[0011] To address the shortcomings of existing technologies, this invention provides an automatic control system for synchronous grouting in tunnel boring machines (TBMs). This control system accurately measures the grouting volume to suit synchronous grouting scenarios, constructs a linkage system between tunneling speed and grouting rate, and achieves full-process synchronous coordination between grouting operations and TBM tunneling. It also establishes a coupled correlation model among tunneling speed, grouting rate, and grouting pressure, enabling precise management of synchronous grouting from parameter coordination to quality control.

[0012] To achieve the above technical objectives, the present invention provides an automatic control system for synchronous grouting of shield tunnels. The automatic control system includes a data acquisition and preprocessing module, a coupled correlation calculation module, a dynamic control module, and an effect feedback and parameter optimization module that are interconnected.

[0013] The data acquisition and preprocessing module is used to acquire dynamic construction parameters and static design parameters during the shield tunneling process. The dynamic construction parameters include shield machine operating parameters and grouting parameters, and the static design parameters include geological parameters, shield machine structural design parameters, and grouting slurry characteristic parameters.

[0014] The coupled correlation calculation module calculates the theoretical volume growth rate of the shield tail annulus based on the shield tunneling speed and other multi-source data collected in real time by the data acquisition and preprocessing module, and corrects the calculation of the target grouting rate according to the geological conditions. Then, it calculates the required driving pressure by combining the grout rheological parameters and pipeline resistance, and finally generates grouting pump control commands within the safe pressure range.

[0015] The dynamic control module receives control commands output by the coupled correlation calculation module and is used to control the grouting flow rate of the synchronous grouting system.

[0016] The effect feedback and parameter optimization module iteratively corrects the formation leakage correction coefficient, dynamic redundancy coefficient, and pipeline friction parameters based on the effective grouting volume, pressure curve, and ground penetrating radar or ultrasonic detection results after each ring construction, so that the system gradually adapts to the real formation conditions during long-distance tunneling.

[0017] A further technical solution of the present invention: the dynamic construction parameters include the real-time tunneling speed v of the shield and the real-time grouting rate Q. 实 Cumulative grouting volume Q 总 Real-time grouting pressure P 实 The geological parameters include soil density ρ. 土 The parameters include: water content w, porosity n, and permeability coefficient k; the shield machine structural design parameters include cutterhead outer diameter D1, segment outer diameter D2, annular thickness h, and segment compressive strength σ; the grouting slurry characteristic parameters include slurry density ρ. 浆 slurry viscosity η p The parameters include setting time (t), conductivity, and the real-time grouting rate, which is measured by electromagnetic flowmeters installed on each branch grouting pipeline. The real-time grouting pressure is measured by a corrosion-resistant pressure sensor near the shield tail section. The cumulative grouting volume is Q. 总 The data is obtained from the synchronous grouting system control unit PLC; the main unit operation data is provided by the shield tunneling main control PLC; the shield machine structural design parameters, geological parameters and grouting slurry characteristic parameters are obtained from the shield machine design drawings, geological survey reports and slurry test reports respectively.

[0018] The preferred technical solution of this invention is as follows: The coupled correlation calculation module calculates the target grouting rate Q required for the current single-ring construction based on the multi-source data collected by the data acquisition and preprocessing module through the volume matching equation of tunneling speed-grouting rate. 目标 The initial value, and the calculated target grouting rate Q 目标 After unit conversion, the initial value was used to calculate the theoretical predicted grouting pump pressure P under the current working conditions using Bingham's fluid pressure formula. 预测 And based on the predicted grouting pump pressure value P 预测 Based on the benchmark, and taking into account the permissible pressure limit of the tunnel lining segments, the pressure required for effective grout diffusion, the permissible pressure of the equipment, the formation conditions, and the results of on-site injection calibration, the safe pressure range [P] was determined. 下限 P 上限 The real-time collected grouting pump pressure P 实 With [P] 下限 P 上限 Compare and correct Q in reverse based on the comparison results. 目标， This allows for the determination of the target grouting rate Q that matches the current tunnel boring speed v. 目标 Pressure control constraints and corresponding control commands.

[0019] The preferred technical solution of this invention is as follows: The effect feedback and parameter optimization module automatically stores the construction data of each ring to establish a historical database. Based on the historical data, the resistance coefficient and correction coefficient in the coupling equation are optimized through machine learning algorithms to improve the model's adaptation accuracy in different strata. The stored data includes tunneling speed, grouting rate, pressure, geological parameters, and filling effect. The effect feedback and parameter optimization module is equipped with a manual intervention interface, which allows operators to manually adjust the target parameter range based on their field experience. After adjustment, the model automatically learns and adapts.

[0020] The preferred technical solution of the present invention is as follows: the synchronous grouting system control unit PLC and the shield main control PLC exchange data through the S7 communication protocol to coordinate and dynamically match the start and stop of tunneling speed and grouting rate.

[0021] The preferred technical solution of the present invention is as follows: the installation position of the electromagnetic flowmeter meets the requirements that the upstream straight pipe section length is ≥5 times the diameter of the branch grouting pipe and the downstream straight pipe section length is ≥3 times the diameter of the branch grouting pipe, and the electromagnetic flowmeter is installed horizontally with the electrode axis parallel to the horizon; the electromagnetic flowmeter and the pipeline are grounded separately with a grounding resistance ≤10Ω; a rubber shock-absorbing pad is installed between the electromagnetic flowmeter and the pipeline.

[0022] A further technical solution of the present invention: calculating the target grouting rate Q 目标 The volume matching equation for the tunneling speed-grouting rate is as follows:

[0023] Q 目标 = k 地质 ×[π / 4×(D1²-D2²)×v×10 -6 ]×(1 + k 冗余 )

[0024] In the formula: Q 目标 is the target grouting rate, in L / min; v is the real-time tunneling speed of the tunnel boring machine, in mm / min;

[0025] D1 is the outer diameter of the tunnel boring machine cutterhead, in mm; D2 is the outer diameter of the tunnel segment, in mm.

[0026] π / 4 ×(D1²- D2²)×v×10 -6 It is the instantaneous annular volume generation rate, in L / min;

[0027] k 地质 It is a geological correction factor, with 1.1 to 1.2 for soft soil and water-rich strata, 0.95 to 1.05 for hard rock and intact strata, and 1.2 to 1.3 for fractured strata, to compensate for slurry loss in highly permeable or fractured strata;

[0028] k 冗余It is the diffusion redundancy coefficient, which is taken as 0.05 to 0.1 and can be dynamically adjusted according to the grouting pressure feedback.

[0029] A further technical solution of the present invention: P is calculated using Bingham's fluid pressure formula. 预测 The specific process is as follows: The calculated target grouting rate Q... 目标 Before substituting into the pressure formula, first convert the units to Q, i.e., Q = Q 目标 / 60000, where Q 目标 The unit of is L / min, and the unit of Q is m³ / s;

[0030] P 预测 =ΔP1+ΔP2+P0

[0031] P 预测 =2L / R·(τ0+4η p Q / πR³)+2L 环空 / (r2-r1)·[τ0+ 4η p Q / (π(r2 4 -r1 4 ) / r2)] +P0

[0032] Introducing field correction factor k 阻力 That is, we get:

[0033] P 预测 = k 阻力 ·{2L / R・[τ0+ 4η p Q / (πR³)] + 2L 环空 / (r2-r1) ·[τ0 + 4η p Q / (π(r2 4 -r1 4 ) / r2)]} + P0

[0034] In the above formula: P 预测 The pressure value of the grouting pump is to be predicted, in Pa, and is the parameter to be determined;

[0035] Q is the target grouting rate. 目标 The pressure flow rate is calculated using unit conversion, with units of m³ / s.

[0036] k 阻力 , is the field resistance correction coefficient, a dimensionless parameter, used to correct for pressure prediction deviations caused by pipeline resistance, shield tail annulus resistance, and changes in field construction conditions.

[0037] P0 is the correction value for the starting pressure of slurry flow, in Pa, determined by field test;

[0038] ΔP1 is the pressure loss along the pipeline, in Pa; ΔP2 is the pressure loss along the annulus, in Pa.

[0039] τ0 is the slurry yield stress, in Pa;

[0040] L is the length of the grouting pipeline, in meters; R is the inner radius of the grouting pipeline, in meters.

[0041] η p The viscosity of the grout is expressed in Pa·s.

[0042] L 环空 This is the effective length of the shield tail annulus, in meters, and is consistent with the length of the shield tail of the tunnel boring machine.

[0043] r1 is the outer radius of the tunnel segment, in meters; r2 is the ground excavation radius, in meters; r2-r1 is the annular thickness.

[0044] The preferred technical solution of the present invention: the safe pressure range [P] 下限 P 上限 The calculation is as follows:

[0045] P 下限 =max(P 有效注浆阈值 P 扩散下限 P 预测 ×(1-β))

[0046] P 上限 =min(P 管片允许压力 P 设备允许压力 P 地层允许压力 P 预测 ×(1+α));

[0047] Among them, P 下限 P is the lower limit of the safe pressure range. 上限 P represents the upper limit of the safe pressure range. 有效注浆阈值 To ensure the minimum pressure required for effective grout injection; P 扩散下限 The minimum pressure required to ensure effective diffusion of the slurry within the shield tail annulus; P 管片允许压力 P 设备允许压力 and P 地层允许压力 These represent the upper limits of the allowable pressure that the segment structure, grouting equipment, and construction stratum can withstand; P 预测 The predicted grouting pump pressure value is calculated based on Bingham's fluid pressure formula; α and β are the field-calibrated pressure allowable deviation coefficients, determined by field test injection, geological category, and historical construction data.

[0048] The preferred technical solution of this invention is to use the real-time collected grouting pump pressure P 实 With [P] 下限 P 上限Compare and correct Q in reverse based on the comparison results. 目标 The process is as follows:

[0049] The real-time collected grouting pump pressure P 实 With [P] 下限 P 上限 Comparison,

[0050] When P 下限 ≤ P 实 ≤ P 上限 At that time, keep the current Q 目标 And based on the real-time grouting rate Q 实 With Q 目标 The deviation is finely adjusted using PID control.

[0051] When P 实 > P 上限 When Q decreases 目标 Alternatively, reduce the opening of the proportional valve to increase the real-time grouting rate Q. 实 reduce;

[0052] When P 实 < P 下限 Furthermore, when the cumulative grouting volume is insufficient, Q should be increased. 目标 Alternatively, increase the opening of the proportional valve to increase the real-time grouting rate Q. 实 improve;

[0053] When there is prolonged low pressure and high flow, it is judged as an abnormality such as grout leakage or grout return and an alarm is triggered.

[0054] The system of this invention takes the shield tunneling speed as input, the increase in the volume of the shield tail annulus as the basis, and the grouting pressure safety boundary as the constraint. Through multi-source sensing, data cleaning, volume matching, fluid pressure extrapolation and servo closed-loop control, it realizes the adaptive adjustment of the grouting rate according to the tunneling state and the dynamic control of the grouting pressure within the safe range.

[0055] When performing multi-dimensional modeling calculations, the system of this invention first runs the volume matching equation of tunneling speed-grouting rate to obtain the target grouting rate required at the moment. Then, this rate value is substituted as a known variable into the hydrodynamic coupling equation of grouting rate-grouting pressure to calculate the corresponding theoretical pressure safety range. If the system determines that the pressure generated at this grouting rate will exceed the set safety limit, it will trigger the highest priority protection mechanism, which will forcibly reduce the grouting rate given by the first formula.

[0056] The beneficial effects of this invention are:

[0057] (1) The present invention selects an electromagnetic flowmeter adapted to the synchronous grouting scenario. In view of the technical pain points of low accuracy and severe lining wear of traditional flowmeters in thick slurry monitoring, the sensor structure and measurement algorithm are optimized. With the support of the hardware and software collaborative architecture, a dynamic linkage system of tunneling speed and grouting rate is constructed to solve the problem of "asynchronous response and inaccurate adaptation" in traditional control. A precise matching mode of "dynamic change of tunneling rhythm and real-time adjustment of grouting rate" is formed, and finally the grouting operation and shield tunneling are synchronized and coordinated throughout the entire process, so as to realize high-precision, long-life stable monitoring of thick slurry flow.

[0058] (2) This invention establishes a collaborative coupling correlation model of tunneling speed, grouting rate and grouting pressure, and quantifies the dynamic coupling relationship of the three in complex strata through algorithms. It also constructs a full-process control mechanism of "real-time perception of construction status - accurate calculation of target parameters - dynamic adjustment of grouting system - closed-loop verification of filling effect" to realize the precise management of synchronous grouting from parameter coordination to quality control.

[0059] (3) This invention reduces labor costs. The system's automated control function reduces reliance on human experience, reduces manual intervention by 60%, and increases construction efficiency by 15% to 20%. It eliminates the need for frequent manual adjustments to grouting rates and pressures based on tunneling speed, reducing the workload of operators and errors caused by human factors, thereby reducing manpower input and labor costs. Traditional shield tunneling synchronous grouting construction requires multiple experienced operators to constantly monitor tunneling speed and grouting parameters and make manual adjustments. With this system, only a small number of operators are needed for monitoring and maintenance, significantly saving labor costs.

[0060] (4) The present invention improves construction safety; the present invention can effectively avoid safety problems such as segment deformation, rupture and ground heave caused by excessive grouting pressure through precise grouting control, and significantly improves the safety of shield tunneling; in shield tunneling under some complex geological conditions, accidents such as segment rupture and ground collapse have occurred due to improper control of grouting parameters. However, after applying this system, these safety hazards have been effectively avoided, ensuring the safety of construction personnel and the smooth progress of the project.

[0061] (5) This invention improves construction quality; through this coupled correlation model and the whole process linkage mechanism, the following can be achieved: the matching accuracy between grouting rate and tunneling speed is ≤ ±2.5%, avoiding untimely filling or grout waste; the grouting pressure is controlled within the safe range, and the segment damage rate is reduced by more than 80%; the annular filling density is ≥95%, and the surface settlement is controlled within the design allowable range; the start-stop synchronization is achieved, the grouting pump starts within 1 second after tunneling starts, and switches to the pressure holding rate within 0.5 seconds after tunneling stops, with no empty tunneling or ineffective grouting; the rate matching accuracy is achieved, the matching deviation between grouting rate and tunneling speed is ≤ ±2.5%, the annular filling density is ≥96%, and there are no voids or segment settlement problems. Attached Figure Description

[0062] Figure 1 This is a system control principle diagram of the present invention;

[0063] Figure 2 This is a flowchart of the automatic control process for synchronous grouting in shield tunneling according to an embodiment of the present invention. Detailed Implementation

[0064] The present invention will be further described below with reference to specific embodiments.

[0065] The embodiment provides an automatic control system for synchronous grouting of a tunnel boring machine. The automatic control system includes a data acquisition and preprocessing module, a coupled correlation calculation module, a dynamic control module, and an effect feedback and parameter optimization module that are interconnected.

[0066] The data acquisition and preprocessing module is used to acquire dynamic construction parameters and static design parameters during the shield tunneling process. The dynamic construction parameters include shield machine operating parameters and grouting parameters, while the static design parameters include geological parameters, shield machine structural design parameters, and grouting slurry characteristic parameters. The dynamic construction parameters include the real-time shield tunneling speed v and the real-time grouting rate Q. 实 Cumulative grouting volume Q 总 Real-time grouting pressure P 实 Dynamic construction parameters are the core feedback variables of the model, reflecting the construction status in real time; the geological parameters include soil density ρ. 土 The geological parameters, including water content (w), porosity (n), and permeability coefficient (k), are used to adjust the compatibility between these three parameters to suit different geological formations. The shield machine structural design parameters include cutterhead outer diameter (D1), segment outer diameter (D2), annular thickness (h), and segment compressive strength (σ). These parameters are used to determine the annular volume baseline and limit the pressure safety threshold. The grouting slurry characteristic parameters include slurry density (ρ). 浆Grout viscosity μ, setting time t, and conductivity are used to correct the mechanical transmission relationship between grouting rate and pressure. The real-time grouting rate is measured by electromagnetic flowmeters installed on each branch grouting pipeline, and the real-time grouting pressure is measured by a corrosion-resistant pressure sensor near the shield tail section. The cumulative grouting volume Q is... 总 The data is obtained from the synchronous grouting system control unit PLC; the main unit operation data is provided by the shield tunneling main control PLC; the shield machine structural design parameters, geological parameters and grouting slurry characteristic parameters are obtained from the shield machine design drawings, geological survey reports and slurry test reports respectively.

[0067] In this embodiment, pressure sensors are positioned near the tail section of each branch grouting pipeline. This measurement point reduces the impact of friction loss from the pump station outlet to the pipeline end on pressure determination, allowing the controller to obtain a near-real pressure close to the instant the grout enters the annulus. The pressure sensors and connected metal pipelines are equipped with independent anti-interference grounding with a grounding resistance not exceeding 10Ω. Vibration isolation pads are installed on the mounting base to reduce the impact of vibrations from the main drive motor, frequency converter, and mechanical components on the sensing signal.

[0068] The selection and installation of the electromagnetic flowmeter in this embodiment are based on the synchronous grouting scenario. Electromagnetic flowmeters, based on Faraday's law of electromagnetic induction (the slurry cuts magnetic lines of force to generate an induced electromotive force, which is positively correlated with flow velocity), are theoretically suitable for measuring conductive media. However, synchronous grouting slurries (high viscosity, sand content, discontinuous pumping) are prone to measurement distortion. Traditional flowmeters suffer from low accuracy and severe lining wear in concentrated slurry monitoring. By optimizing the sensor structure and measurement algorithm, high-precision, long-life, and stable monitoring of concentrated slurry flow can be achieved. In this embodiment, the following parameters are emphasized when selecting the electromagnetic flowmeter:

[0069] Electrode material and structure: Hastelloy C is selected, which is resistant to abrasion by sand particles in the slurry and corrosion (suitable for cement-based slurries); "convex electrode" is adopted to avoid signal attenuation caused by slurry adhesion and scaling, and to ensure stable contact between the electrode and the slurry.

[0070] Lining material: polytetrafluoroethylene (PTFE) lining (compatible with corrosive additive slurry), thickness ≥6mm, to avoid magnetic field leakage affecting the measurement after lining wear.

[0071] Diameter and range: The flow meter diameter is consistent with the grouting pipeline diameter (to avoid uneven flow velocity distribution caused by diameter change), quick connection interface, range ratio ≥1:100, adaptable to a wide range of flow velocity changes (usually 0.3~5m / s) of synchronous grouting from "low flow velocity (pressure maintenance grouting) to high flow velocity (rapid filling)".

[0072] Signal converter: The converter uses a "low-frequency rectangular wave + dual-frequency excitation" converter, which has strong anti-interference ability (resisting construction vibration and motor electromagnetic interference); it supports signal filtering and nonlinear correction functions, with a sampling frequency ≥50Hz, to capture instantaneous flow velocity fluctuations in discontinuous pumping.

[0073] In addition to the selection of the electromagnetic flowmeter, the installation of the electromagnetic flowmeter in this embodiment has also been optimized. The synchronous grouting pipeline experiences significant vibration and numerous bends, leading to turbulent flow fields that can easily cause signal distortion in the electromagnetic flowmeter. Therefore, it is necessary to standardize installation details and optimize the installation to eliminate measurement deviations caused by "flow field interference." The specific installation requirements are as follows:

[0074] Straight pipe section requirements: The length of the straight pipe section upstream of the flow meter should be ≥5 times the pipe diameter, and downstream it should be ≥3 times the pipe diameter. Avoid placing it close to elbows, valves, or pump outlets (to reduce the impact of uneven flow velocity distribution).

[0075] Installation posture: "Horizontal installation" is adopted, with the electrode axis parallel to the horizon (to avoid sand particles in the slurry depositing and covering the electrode).

[0076] Grounding and vibration reduction: The flow meter body and pipeline are grounded separately (grounding resistance ≤10Ω) to avoid electromagnetic interference; rubber shock-absorbing pads are installed between the flow meter and the pipeline to reduce the impact of tunnel boring machine vibration on the sensor and prevent the electrodes and lining from loosening.

[0077] In this embodiment, the electromagnetic flowmeter with its built-in motherboard monitors and controls the flow, primarily filtering the acquired signals. Due to factors such as fluctuations in the conductivity of the grout during synchronous grouting, discontinuous pumping, and ineffective grouting (vacuuming, grout return), the inherent deviations caused by the combination of grout characteristics and construction conditions can be corrected through the built-in algorithm of the electromagnetic flowmeter.

[0078] Dynamic conductivity compensation algorithm: Real-time acquisition of slurry conductivity data (some flow meters have built-in conductivity monitoring function). When the conductivity is lower than the threshold (usually ≥5μS / cm), the flow meter's built-in motherboard chip automatically adjusts the excitation current and signal amplification factor to avoid weak signal and inaccurate measurement due to insufficient conductivity. The acquisition of slurry conductivity, automatic adjustment of excitation current, and acquisition and filtering of flow velocity pulsation signals are all independently monitored and controlled by the flow meter's built-in motherboard chip. For this part of the compensation algorithm, all actions are completed by the electromagnetic flow meter itself without the need for host computer intervention.

[0079] Discontinuous pumping correction algorithm: To address the flow velocity pulsations ("peak-valley" fluctuations) caused by the reciprocating motion of the grouting pump piston, a "moving average filter" (taking the average flow velocity over 50-100ms) is used to eliminate instantaneous pulse interference and output stable flow velocity data. Simultaneously, a "minimum effective flow velocity threshold" is set; when the flow velocity is below the threshold (e.g., 0.1m / s), it is determined that the pump body has sucked in air and is not included in the effective grouting volume. This control process mainly includes conductivity compensation and moving average filtering. Specifically, the conductivity compensation logic involves the flowmeter motherboard chip acquiring real-time slurry conductivity data between the electrodes. When the conductivity is detected to be below the preset threshold, the chip automatically outputs a control command to the excitation coil, increasing the excitation current and improving the signal amplification factor of the internal amplifier circuit, thereby avoiding measurement inaccuracies. The moving average filtering logic addresses the instantaneous pulse interference caused by the reciprocating motion of the grouting pump piston. The flowmeter motherboard chip sends the acquired discrete flow velocity signal to the internal filtering algorithm module, which extracts the most recent 50-100ms flow velocity data. The average value of continuous sampling points within ms is calculated, and the smoothed average value is used as the current flow rate output. At the same time, the chip internally sets a "minimum effective flow rate threshold". When the calculated smoothed flow rate is lower than this value, the chip determines that the pump body has sucked in air, directly removes the data at the bottom layer, and does not include it in the cumulative grouting volume.

[0080] Pressure-linked rejection algorithm: Combining data from pressure sensors on the pipeline, when the pressure is lower than the "effective grouting pressure threshold" (based on geological presets), it is judged as an invalid working condition such as grout return or leakage. Flow accumulation calculation is paused, and only the grouting volume when the pressure meets the standard is counted, thus solving the problem of "falsely high counts". The control unit PLC of the synchronous grouting system reads the pressure value returned by the pipeline pressure sensor in real time through the analog input module, and simultaneously receives the instantaneous flow value returned by the flow meter. The PLC's internal program executes the following logic: Even if the flow meter shows flow input, if the pressure value returned by the pressure sensor is lower than the preset "effective grouting pressure threshold", the program determines that the current state is "grout leakage or no-load". At this time, the PLC pauses the execution of the grouting volume accumulation program (i.e., "flow but low pressure is judged as grout leakage and not counted"), thus solving the problem of falsely high metering.

[0081] In this embodiment, the coupled correlation calculation module calculates the theoretical volume growth rate of the shield tail annulus based on the shield tunneling speed and other multi-source data collected in real time by the data acquisition and preprocessing module, and corrects the calculation to obtain the target grouting rate according to the geological conditions. Then, it calculates the required driving pressure by combining the grout rheological parameters and pipeline resistance, and finally generates grouting pump control commands within the safe pressure range. The coupled correlation calculation module calculates the target grouting rate Q required for the current single-ring construction based on the multi-source data collected by the data acquisition and preprocessing module through the volume matching equation of tunneling speed-grouting rate. 目标 The initial value, and the calculated target grouting rate Q 目标The initial value is used to calculate the theoretically predicted grouting pump pressure P under the current working condition using Bingham's fluid pressure formula. 预测 And based on the predicted grouting pump pressure value P 预测 Based on the benchmark, and taking into account the permissible pressure limit of the tunnel lining segments, the pressure required for effective grout diffusion, the permissible pressure of the equipment, the formation conditions, and the results of on-site injection calibration, the safe pressure range [P] was determined. 下限 P 上限 The real-time collected grouting pump pressure P 实 With [P] 下限 P 上限 Compare and correct Q in reverse based on the comparison results. 目标 However, tunneling speed (v), grouting rate (Q), and grouting pressure (P) are not isolated factors. Tunneling speed determines the rate of annular formation, grouting rate determines the filling efficiency, and grouting pressure determines the grout diffusion range and support effect. These three factors are mutually restrictive and influential. In this embodiment, the coupled correlation calculation module constructs a three-in-one coupled correlation model of "geological parameters - equipment status - construction parameters," establishing a full-process linkage mechanism of "real-time perception - precise calculation - dynamic control - closed-loop verification." This breaks the traditional "isolated control" mode, achieving adaptive coordination among the three factors and ensuring a balance between grouting quality, construction safety, and efficiency under complex geological and dynamic tunneling conditions. The specific process is as follows:

[0082] I. Basic Coupling: Volume Matching Equation of Tunneling Speed-Grouting Rate

[0083] The core logic of the implementation example is that the grouting rate needs to be dynamically matched with the annulus generation rate, while reserving redundancy for grout diffusion and leakage, and the target grouting rate Q is calculated by combining geological characteristics. 目标 :

[0084] Q 目标 = k 地质 ×[π / 4×(D1²-D2²)×v×10 -6 ]×(1 + k 冗余 )

[0085] In the formula: Q 目标 is the target grouting rate, in L / min; v is the real-time tunneling speed of the tunnel boring machine, in mm / min;

[0086] D1 is the outer diameter of the tunnel boring machine cutterhead, in mm; D2 is the outer diameter of the tunnel segment, in mm.

[0087] π / 4 ×(D1²- D2²)×v×10 -6 It is the instantaneous annular volume generation rate, in L / min;

[0088] k地质 It is a geological seepage correction coefficient. For highly permeable strata such as water-rich silty fine sand and silty soft soil, it is taken as 1.1 to 1.2. For intact slightly weathered hard rock or low-permeability strata, it is taken as 0.95 to 1.05. For strata with high leakage risk such as fault fracture zones and karst fissures, it is taken as 1.2 to 1.3. It is used to compensate for the leakage of slurry in highly permeable or fractured strata.

[0089] k 冗余 This is the diffusion redundancy coefficient, with an initial value typically between 0.05 and 0.1. This parameter is corrected based on subsequent pressure feedback, grouting effect detection, and historical construction data. Through this model, the system converts the tunnel boring machine's advance speed into a target grouting rate, causing the grouting displacement to vary with the annulus generation rate.

[0090] The core purpose of this formula is to accurately and in real-time convert the instantaneous annular space generation rate into the corresponding grouting volume flow rate control target during single-ring tunneling. In actual construction, shield tunneling and synchronous grouting start and end simultaneously on the time axis. This formula mathematically establishes the basic execution benchmark that the grouting rate must strictly follow the tunneling speed and dynamically change synchronously.

[0091] II. Mechanical Coupling: Fluid Dynamics Equation of Grouting Rate vs. Grouting Pressure

[0092] Fluid dynamics characteristics (the grout is plastic when stationary, and only flows after shear stress exceeds the yield stress). Based on the principles of energy conservation and resistance balance in grout flow, a mechanical coupling equation for grouting rate and grouting pressure is established to clarify the quantitative relationship between the two, while also incorporating the influence of pipeline resistance, annular resistance, and grout viscosity.

[0093] (1) Basic assumptions: The grout is Bingham fluid and the flow process is steady-state laminar flow; the grouting pipeline is a circular pipe with a uniform cross section, and the shield tail annulus is simplified to a concentric annular gap; the influence of grout gravity and inertial force is ignored, and only the resistance generated by viscous resistance and yield stress is considered; the grouting pressure is used entirely to overcome the pipeline resistance, annular resistance and yield resistance of grout flow.

[0094] (2) Bingham fluid constitutive equation:

[0095] Shear stress τ and shear rate of Bingham fluid The following relationship must be satisfied:

[0096]

[0097] In the formula: τ0 is the yield stress of the slurry (Pa); it is determined by the slurry mix ratio and concentration.

[0098] η p The plastic viscosity of the slurry (Pa·s) reflects the internal friction characteristics of the slurry during flow.

[0099] Shear rate (s) -1 ), which is positively correlated with the fluid flow velocity gradient.

[0100] (3) Calculation of resistance in grouting pipeline (circular pipe flow): When the grout flows in the grouting pipeline (circular pipe), it needs to overcome the frictional resistance of the pipeline. For the steady-state laminar flow of Bingham fluid in the circular pipe, the formula for calculating the frictional pressure loss ΔP1 is: ΔP1=2L / R・(τ0 + 4η p Q / πR³)

[0101] Where: L is the length of the grouting pipeline (m); R is the inner radius of the grouting pipeline (m);

[0102] Q is the target grouting rate. 目标 The pressure flow rate is calculated using unit conversion, and the unit is m³ / s.

[0103] (4) Calculation of resistance in the shield tail annulus (annular gap flow). The shield tail annulus is the annular gap between the outer wall of the tunnel segment and the formation, simplified to a concentric annular gap (the inner circle is the tunnel segment, and the outer circle is the excavation face of the formation). When Bingham fluid flows in the annular gap, the formula for calculating the friction loss ΔP2 along the annulus is:

[0104] ΔP2=2L 环空 / (r2-r1)・[τ0 + 4η p Q / (π(r2 4 -r1 4 ) / r2)]

[0105] In the formula: L 环空 The effective length of the shield tail annulus (m) is consistent with the length of the shield tail of the tunnel boring machine;

[0106] r1 is the outer radius of the tunnel segment (m); r2 is the ground excavation radius (m); r2-r1 is the annular thickness;

[0107] Q is the target grouting rate Q 目标 The pressure calculation flow rate (m³ / s) is obtained after unit conversion; τ0 is the slurry yield stress (Pa).

[0108] (5) Grouting rate-grouting pressure coupling equation

[0109] Grouting pump output pressure P 预测 It is necessary to overcome the resistance of the grouting pipeline ΔP1 and the resistance of the shield tail annulus ΔP2, while also satisfying the initiation conditions for grout flow. Therefore, the overall coupling equation is:

[0110] P 预测 =ΔP1+ΔP2+P0

[0111] Introducing field correction factor k 阻力 That is, we get:

[0112] P 预测 = k 阻力 ·{2L / R·[τ0+ 4η p Q / (πR³)] + 2L 环空 / (r2-r1)·[τ0+ 4η p Q / (π(r2 4 -r1 4 ) / r2)]} + P0

[0113] In the above formula: P 预测 The pressure value of the grouting pump is to be predicted, in Pa, and is the parameter to be determined;

[0114] Q is the target grouting rate. 目标 The calculated pressure flow rate is in m³ / s.

[0115] k 阻力 , is the field resistance correction coefficient, a dimensionless parameter used to correct for pressure prediction deviations caused by changes in pipeline resistance, shield tail annulus resistance, and changes in field construction conditions. Its value can be determined by field injection tests, historical pressure curves, and pipeline friction calibration results, and iteratively corrected within a preset range.

[0116] P0 is the correction value for the starting pressure of slurry flow, in Pa, determined by field test;

[0117] ΔP1 is the pressure loss along the pipeline, in Pa; ΔP2 is the pressure loss along the annulus, in Pa.

[0118] τ0 is the slurry yield stress, in Pa;

[0119] L is the length of the grouting pipeline, in meters; R is the inner radius of the grouting pipeline, in meters.

[0120] η p The viscosity of the grout is expressed in Pa·s.

[0121] L 环空 This is the effective length of the shield tail annulus, in meters, and is consistent with the length of the shield tail of the tunnel boring machine.

[0122] r1 is the outer radius of the tunnel segment, in meters; r2 is the excavation radius of the stratum, in meters; and r2-r1 is the thickness of the annulus.

[0123] The core purpose of this fluid dynamics equation is to define the physical boundaries for the safe operation of the entire synchronous grouting system. While the volume matching formula mentioned earlier addresses the question of how much grout should be injected at the current tunneling speed, this fluid dynamics formula addresses the question of how much pressure the system will ultimately withstand if grouting is carried out at this target rate, after overcoming the yield stress of the high-viscosity grout and the frictional resistance of the pipeline and the shield tail annulus. It not only serves as a basis for assessing whether the grout can be pumped smoothly but also acts as a safety lock to prevent the segments from fracturing due to excessive pressure.

[0124] In the execution steps of the overall control logic, the fluid dynamics equations and the volume matching equations for tunneling speed and grouting rate are sequentially linked and coordinated. When the system performs multi-dimensional modeling calculations, it must first run the volume matching equations for tunneling speed and grouting rate to obtain the target grouting rate required at the current time. Then, it substitutes this rate value as a known variable into the fluid dynamics equation formula to calculate the corresponding theoretical pressure safety range. If the system determines that the pressure generated at this grouting rate will exceed the set safety limit, it will trigger the highest priority protection mechanism, which will then forcibly reduce the grouting rate given by the first formula.

[0125] II. Analysis of Key Influencing Factors;

[0126] Slurry viscosity (η) p The higher the plastic viscosity, the higher the flow resistance of the grout, and the greater the grouting pressure required at the same grouting rate.

[0127] Pipeline / annulus geometry parameters: The smaller the inner diameter of the pipeline and the thinner the annulus, the greater the resistance, and the more significant the increase in grouting pressure with the grouting rate.

[0128] Yield stress (τ0): The yield stress of the slurry determines the minimum pressure required to start the flow. The higher the yield stress, the greater the proportion of pressure loss used to overcome plastic resistance.

[0129] III. Three-dimensional coupling: coordination of tunneling speed, grouting rate, and grouting pressure;

[0130] With the goal of "effective filling of the annulus", the above two equations are integrated, and geological parameters and construction status correction terms are introduced to form a three-dimensional coupled model:

[0131] P 预测 = k 阻力 ·{2L / R・[τ0+ 4η p Q / (πR³)] + 2L 环空 / (r2-r1) ·[τ0 + 4η p Q / (π(r2 4 -r1 4 ) / r2)]} + P0

[0132] Q 目标 = k 地质 ×[π / 4×(D1²-D2²)×v×10 -6 ]×(1 + k 冗余 )

[0133] The coordination process of the two formulas is as follows:

[0134] When the tunneling speed v changes, the target grouting rate Q is first calculated. 目标 Substitute the calculated target grouting rate into P 预测 The calculation formula calculates the predicted pressure value P. 预测 The calculated target grouting rate Q 目标 Before substituting into the pressure formula, first convert the units to Q, i.e., Q = Q 目标 / 60000, where Q 目标 The unit is L / min, and the unit of Q is m³ / s, to predict the grouting pump pressure value P. 预测 Based on the benchmark, and taking into account the permissible pressure limit of the tunnel lining segments, the pressure required for effective grout diffusion, the permissible pressure of the equipment, the formation conditions, and the results of on-site injection calibration, the safe pressure range [P] was determined. 下限 P 上限 The real-time collected grouting pump pressure P 实 With [P] 下限 P 上限 Compare and correct Q in reverse based on the comparison results. 目标， This allows for the determination of the target grouting rate Q that matches the current tunnel boring speed v. 目标 The grouting pump output pressure control constraints and corresponding control commands.

[0135] The safe pressure range [P] 下限 P 上限 The calculation is as follows:

[0136] P 下限 =max(P 有效注浆阈值 P 扩散下限 P 预测 ×(1-β))

[0137] P 上限 =min(P 管片允许压力 P 设备允许压力 P 地层允许压力 P 预测 ×(1+α));

[0138] Among them, P 下限 P is the lower limit of the safe pressure range. 上限 P represents the upper limit of the safe pressure range.有效注浆阈值 To ensure the minimum pressure required for effective grout injection; P 扩散下限 The minimum pressure required to ensure effective diffusion of the slurry within the shield tail annulus; P 管片允许压力 P 设备允许压力 and P 地层允许压力 These represent the upper limits of the allowable pressure that the segment structure, grouting equipment, and construction stratum can withstand; P 预测 The predicted grouting pump pressure value is calculated based on Bingham's fluid pressure formula; α and β are the field-calibrated pressure allowable deviation coefficients, determined by field test injection, geological category, and historical construction data.

[0139] The real-time collected grouting pump pressure P 实 With [P] 下限 P 上限 Compare the results and correct Q in reverse. 目标 The process is as follows

[0140] When P 下限 ≤ P 实 ≤ P 上限 At that time, keep the current Q 目标 And based on the real-time grouting rate Q 实 With Q 目标 The deviation is finely adjusted using PID control.

[0141] When P 实 > P 上限 When Q decreases 目标 Alternatively, reduce the opening of the proportional valve to increase the real-time grouting rate Q. 实 reduce;

[0142] When P 实 < P 下限 Furthermore, when the cumulative grouting volume is insufficient, Q should be increased. 目标 Alternatively, increase the opening of the proportional valve to increase the real-time grouting rate Q. 实 improve;

[0143] When there is prolonged low pressure and high flow, it is judged as an abnormality such as grout leakage or grout return and an alarm is triggered.

[0144] Taking complex formations as an example, the target grouting volume and the safe pressure boundary may conflict. To avoid instability in the control system between tracking the target grouting volume and maintaining pressure safety, a dynamic priority arbitration logic is adopted. Its overall operation steps and branch judgments are as follows: Figure 1 As shown. When the actual pressure P 实 More than P 上限If the system determines that there may be pipeline blockage, low permeability of hard rock, obstruction of grouting channels, or local pressure accumulation, the controller immediately disables the volume tracking task and issues a rapid discharge reduction command to the electro-hydraulic proportional valve, with a valve position reduction of no less than 10% per cycle. If the pressure does not drop within several consecutive control cycles, the system triggers forced pump shutdown or pressure relief protection to prevent segment damage, shield tail seal failure, and pipeline rupture.

[0145] When the cumulative effective grouting volume of a certain ring is less than 80% of the theoretical target, and P 实 For a long time, the level was below P. 下限 When the system determines that it may have entered a highly leaky stratum such as a water-rich sand layer, a fault fracture zone, or a karst cavity, the controller switches to active compensation mode, increasing the grouting pump discharge rate, with a single-cycle increase not exceeding 15%, to suppress overshoot. This mode compensates for stratum leakage and maintains the outer support of the lining by increasing the grout supply and pressure level.

[0146] When P 实 Located in [P 下限 P 上限 Within the specified range, when the measured flow rate is close to the target flow rate, the system enters steady-state closed-loop control. The controller employs a PID algorithm combined with a fuzzy control strategy, fine-tuning the 4-20mA output signal based on flow rate error, pressure error, and error change rate to achieve smooth tracking of the grouting rate and low pressure fluctuation operation. This control method reduces the impact of hydraulic hysteresis, pumping pulsation, and pipeline disturbances on grouting stability. The system is equipped with start-stop interlocking logic. After the shield cutterhead starts and enters the tunneling state, the grouting pump automatically starts within 1 second to avoid grouting lag after tunneling begins. When the shield is paused due to ring replacement, maintenance, or fault, the grouting system switches to a low-flow pressure-maintaining mode within 0.5 seconds instead of directly stopping the pump, to maintain the foundation pressure in the shield tail area and reduce the risk of ground creep and settlement during shutdown. In the event of long-term shutdown or grout switching, the system can automatically execute clean water flushing and anti-consolidation procedures to reduce the probability of pipeline blockage.

[0147] Because geological survey data is discrete and cannot fully reflect the actual geological changes within long-distance shield tunneling sections, this embodiment includes an effect feedback and parameter optimization module. This module iteratively corrects the ground leakage correction coefficient, dynamic redundancy coefficient, and pipeline friction parameters based on the effective grouting volume, pressure curve, and ground-penetrating radar or ultrasonic detection results after each ring's construction, enabling the system to gradually adapt to real geological conditions during long-distance tunneling. The effect feedback and parameter optimization module automatically stores construction data for each ring to establish a historical database. Based on this historical data, it optimizes the resistance coefficient and correction coefficient in the coupling equation using machine learning algorithms, improving the model's adaptability to different geological formations. The stored data includes tunneling speed, grouting rate, pressure, geological parameters, and filling effect. The effect feedback and parameter optimization module also includes a manual intervention interface, allowing operators to manually adjust the target parameter range based on field experience. After adjustment, the model automatically learns and adapts. The system includes real-time updates and equipment status updates, specifically:

[0148] Real-time updates: Based on sensor data (acquisition frequency ≥20Hz), the instantaneous tunneling speed, grouting rate, and pressure data are updated every 50ms, and the target parameters output by the model are dynamically adjusted. The system corrects the model parameters by updating the data of each sensor in real time. The latest grouting rate calculated at the end will be directly used as a control command and sent to the electro-hydraulic proportional control valve at the back end, thereby realizing the physical adjustment of the grouting pump discharge.

[0149] Equipment status update: By analyzing the grouting pump running time and sensor calibration data, the pump efficiency coefficient and pipeline resistance coefficient are corrected to compensate for deviations caused by equipment wear.

[0150] In this embodiment, after each ring of tunnel segments is assembled and grouting is completed, the effect feedback and parameter optimization module uses ground-penetrating radar or ultrasonic testing devices deployed through the pre-reserved observation holes in the segments to perform non-destructive testing on the grout filling status behind the segments. The testing targets include the annular void filling thickness, density, crown voids, weak areas on the side shoulders, and honeycomb defects. The test results are then analyzed in the frequency domain and compared with the actual effective grouting volume, target grouting volume, and pressure curve for that ring.

[0151] If the detection reveals voids, insufficient thickness, or uneven filling in the arch or shoulder, it indicates that the current dynamic redundancy coefficient or formation leakage correction coefficient is too small. The system adjusts the geological leakage correction coefficient k based on the defect volume and spatial distribution. 地质 and dynamic redundancy coefficient k 冗余 The amplitude limit was adjusted upwards, and the corrected parameters were used for the grouting calculation of the subsequent ring.

[0152] If the real-time grouting rate Q in consecutive multiple rings 实 Approximate target grouting rate Q 目标 But P实 Long-term proximity to P 上限 This indicates that the current formation permeability is lower than estimated, or that the pipeline friction parameter is too low. The system uses Kalman filtering and historical data fitting to lower the geological leakage correction factor k. 地质 And increase the field resistance correction factor k. 阻力 Simultaneously, pipeline friction parameters and the correlation coefficients of the Bingham fluid model are corrected. If persistent low pressure, high flow rate, and insufficient filling occur, the leakage correction coefficient and redundancy coefficient are increased. Tunneling speed, grouting flow rate, pressure curves, cutterhead torque, jack thrust, grout rheological parameters, and formation parameters are all written to a time-series database with timestamps, forming a digital twin data foundation for the project. The backend system can use statistical analysis and reinforcement learning algorithms to establish empirical resistance coefficient maps under different formation conditions, providing parameter recommendations for subsequent section construction. The system retains a high-level human expert intervention interface; when encountering abnormal conditions beyond the model's applicability, such as unexplored faults, sudden water inrush, or large-scale leakage, manual intervention can be initiated to control the safety pressure boundary and pumping strategy.

[0153] In this embodiment, the coupling correlation calculation module and the dynamic control module are placed in the synchronous grouting system control unit PLC. The synchronous grouting system control unit PLC and the shield main control PLC exchange data through the S7 communication protocol to coordinate and dynamically match the start and stop of tunneling speed and grouting rate.

[0154] Hardware architecture: Select Siemens S7-1200 CPU and expansion modules, along with signal isolators, intermediate relays, and HMIs to collect signals such as tunneling speed (laser displacement sensor), grouting rate, and hydraulic pressure. This enables signal interaction with the Schwing pump hydraulic system to control pump start / stop and electro-hydraulic proportional flow valves.

[0155] S7 Protocol Configuration: In the TIA Portal hardware configuration, set up IP addresses on the same network segment, map variables between the PLC and the pump (such as start / stop, rate control, and status feedback), and add communication fault handling to ensure real-time and reliable data interaction. The synchronous grouting system control unit PLC is the core of the entire system's data acquisition and control. It establishes an Ethernet connection with the main PLC of the tunnel boring machine (the information source) via the S7 protocol to achieve data exchange of basic parameters such as tunneling speed and stroke.

[0156] Control logic: In terms of start-stop linkage, the pump starts and stops or switches the pressure holding rate according to the start and stop of tunneling; in terms of rate matching, the target rate is calculated according to the annular volume formula, and the flow valve is controlled by analog signal. The actual rate feedback is combined with PID fine adjustment. If the pressure exceeds the limit, the speed is reduced.

[0157] The control logic of this system forms a closed-loop signal transmission according to the four steps of "sensing-computation-execution-feedback".

[0158] First, status perception and signal acquisition are carried out. The synchronous grouting control unit (substation PLC) receives start and stop commands from the main PLC of the tunnel boring machine and instantaneous tunneling speed (v) collected by the laser displacement sensor in real time through the S7 communication protocol.

[0159] Subsequently, the target rate formula is calculated. After receiving the tunneling speed v, the substation PLC internal program calls the preset volume matching formula to calculate the current required target grouting rate:

[0160] Q 目标 =k 地质 ×[π / 4×(D1²-D2²)×v×10 -6 ]×(1+k 冗余 );

[0161] Then, the control command is converted and issued. The substation PLC converts the calculated Q target into a 4-20mA analog electrical signal output. This electrical signal is transmitted to the proportional valve amplifier on the grouting trolley. The amplifier converts it into a PWM drive signal to control the valve core opening of the electro-hydraulic proportional flow valve, thereby precisely adjusting the hydraulic displacement of the Schwing grouting pump.

[0162] Finally, a dual closed-loop and deviation fine-tuning process is implemented. The first is the flow fine-tuning loop: the electromagnetic flowmeter installed on the branch line feeds back the actual grouting rate (Qactual) to the substation PLC. The PLC uses a PID algorithm to compare the deviation between the target Q and the actual Q, and fine-tunes the analog signal output to the proportional valve. The second is the pressure intervention loop: the pressure sensor feeds back the pressure at the end of the pipeline to the substation PLC in real time. Once the actual pressure is determined to exceed the safety limit, the PLC triggers the highest priority safety logic, forcibly issuing a deceleration command to reduce the opening of the proportional valve until the pressure drops back to the safe range.

[0163] The hardware protection measures in this embodiment are as follows:

[0164] Sensor selection: Prioritize vibration-resistant, wear-resistant, and high-precision equipment (flow sensor accuracy ±0.5% FS, pressure sensor accuracy ±0.3% FS), with a protection rating of not less than IP67;

[0165] Execution equipment: An electro-hydraulic proportional variable grouting pump (response time ≤ 0.5s) is used to ensure that control commands are implemented quickly;

[0166] Data transmission: Build a dual-redundant network of industrial Ethernet + CAN bus with a transmission delay of ≤10ms to avoid linkage lag.

[0167] The software protection measures are as follows:

[0168] Algorithm optimization: By integrating PID adaptive algorithm and fuzzy control algorithm, the parameter fluctuations caused by geological changes are resolved, achieving "fast response and no overshoot";

[0169] Fault tolerance: When a single sensor fails, it automatically switches to a backup sensor or uses model-based calculations to replace the data, thus avoiding interruption of the linkage.

[0170] Visual monitoring: The host computer displays the curves of "vQP" in real time, marks the deviation between the target value and the actual value, and provides audible and visual alarms when abnormalities occur.

[0171] When the system of the present invention is applied in the field, it includes three stages: hardware deployment, joint debugging and testing, and automatic operation.

[0172] During the hardware deployment phase, the straight pipe sections before and after the flowmeter should meet 5D and 3D requirements, and the installation posture should ensure that the electrode axis is horizontal. The pressure sensor should be placed near the shield tail section and complete anti-corrosion, vibration-proof, and shielded grounding treatment. After all flowmeters arrive on site, they should be calibrated at three points (low flow, medium flow, and high flow) using a standard pressure and flow calibration bench to generate calibration curves. The PLC, analog input / output modules, signal isolators, and communication modules are installed in a vibration-resistant electrical control cabinet. Shielded twisted-pair cables are used for analog cables, and industrial Ethernet cables are used for the communication backbone, with IP address, register address, and communication heartbeat configuration completed.

[0173] During the joint commissioning and testing phase, the system undergoes electromagnetic compatibility testing, signal stability testing, and extreme logic testing. By starting the main drive motor, frequency converter, and hydraulic system, the 4-20mA analog signal is checked for distortion, packet loss, or malfunctions. Simulated abnormal parameters, including ultra-high pressure, extremely low flow, cavitation, pipe blockage, and severe leakage, are input in HMI test mode to verify whether the system executes flow limiting, discharge increase, pressure holding, pump shutdown, and alarm actions according to preset logic. The opening pressure of the mechanical safety relief valve should be verified to form a redundant safety system that combines software control and mechanical protection.

[0174] During the automatic operation phase, construction personnel confirm the current geological parameters, segment dimensions, slurry rheological parameters, and safe pressure range before each day's tunneling. After the system completes sensor zeroing, communication heartbeat checks, and pump status confirmation, it switches to automatic control mode. During operation, the system continuously performs data acquisition, cleaning, volume matching, pressure constraint, priority arbitration, and servo control, and updates the model parameters after each ring of construction is completed.

[0175] The present invention has a fundamental hierarchical difference from the existing technology in terms of logical architecture and engineering implementation. Its core competitiveness is reflected in the anti-interference reconstruction of the physical perception layer, the multi-dimensional decoupling of the control logic layer, and the real-time arbitration mechanism of the execution strategy layer.

[0176] At the physical sensing layer, this application abandons the common pump outlet pressure monitoring mode and strategically moves the pressure sensing array to near the shield tail end. This change in physical location not only completely eliminates the measurement artifacts caused by momentum loss along the grouting pipeline, but also more realistically captures the surrounding rock reaction force at the moment the grout enters the annulus, providing a physical truth value with absolute reference value for the subsequent pressure constraint model. Addressing the industry-wide problem of flowmeter signal drift caused by high-viscosity mortar containing sand, the system incorporates a dynamic conductivity compensation algorithm in its underlying firmware, solving the interference from changes in medium properties that are generally ignored in reference patents. Combined with Hastelloy C material electrodes and Teflon lining, this ensures the long-term high-frequency stability of the metering system under extreme wear conditions.

[0177] In terms of the constitutive logic of the control algorithm, this scheme overcomes the limitations of single-dimensional mapping commonly found in existing patents by employing a two-layer decoupling calculation method of "volume matching deduction followed by fluid dynamics constraints." This application insists on using a local industrial-grade PLC to perform real-time deduction based on the Bingham fluid model. While ensuring the speed of computing power response, it achieves zero-delay tracking of grouting displacement to tunneling speed by deeply linking the cutterhead cutting displacement with the fluid rheological equations. This localized precision control strategy not only avoids the risk of system paralysis caused by communication interruptions but also constructs a deterministic execution closed loop of "injecting all that should be injected and controlling both quantity and pressure" at the physical level.

[0178] In terms of response priority for sudden multi-condition emergencies, the three-level dynamic arbitration logic constructed in this solution endows the tunnel boring machine (TBM) host with "engineering intuition" that surpasses conventional automation. Unlike the rigid feedback adjustment in existing technologies, the system's pre-set priority defense line can instantly erase conventional volume tracking commands and prioritize the activation of hard braking lock-up or advanced overfilling strategies in extreme scenarios such as instantaneous pressure bursts, severe grout leakage, or sudden equipment shutdowns. This rights transfer mechanism based on physical condition judgment greatly reduces the risk of segment breakage or ground collapse caused by system control lag, giving the entire system extremely strong adaptive defense and robustness in the face of geological changes.

[0179] At the system evolution path and interaction level, this application integrates ground-penetrating radar or ultrasonic feedback to transform the segment backfill inspection, which was originally a post-event remedial measure, into a real-time feedback variable participating in model correction, driving the control model to evolve from simple "trajectory tracking" to "effect benchmarking." At the human-machine collaboration level, the system not only supports fully automatic closed-loop cruise but also deeply embeds the geological experience of human experts into the nonlinear control process through a preset parameter write-back interface. In response to the trend of domestic substitution, the system's core hardware can be seamlessly adapted to domestic PLCs and high-performance sensors, ensuring complete independent control of core intellectual property rights while significantly reducing overall machine maintenance costs and supply chain security risks.

Claims

1. An automatic control system for synchronous grouting in tunnel boring machines, characterized in that: The automatic control system includes a data acquisition and preprocessing module, a coupled correlation calculation module, a dynamic control module, and an effect feedback and parameter optimization module that are interconnected. The data acquisition and preprocessing module is used to acquire dynamic construction parameters and static design parameters during the shield tunneling process. The dynamic construction parameters include shield machine operating parameters and grouting parameters, and the static design parameters include geological parameters, shield machine structural design parameters, and grouting slurry characteristic parameters. The coupled correlation calculation module calculates the theoretical volume growth rate of the shield tail annulus based on the shield tunneling speed and other multi-source data collected in real time by the data acquisition and preprocessing module, and corrects the calculation of the target grouting rate according to the geological conditions. Then, it calculates the required driving pressure by combining the grout rheological parameters and pipeline resistance, and finally generates grouting pump control commands within the safe pressure range. The dynamic control module receives control commands output by the coupled correlation calculation module and is used to control the grouting flow rate of the synchronous grouting system. The effect feedback and parameter optimization module iteratively corrects the formation leakage correction coefficient, dynamic redundancy coefficient, and pipeline friction parameters based on the effective grouting volume, pressure curve, and ground penetrating radar or ultrasonic detection results after each ring construction, so that the system gradually adapts to the real formation conditions during long-distance tunneling.

2. The automatic control system for synchronous grouting of a tunnel boring machine according to claim 1, characterized in that: The dynamic construction parameters include the real-time tunneling speed v of the shield and the real-time grouting rate Q. 实 Cumulative grouting volume Q 总 Real-time grouting pressure P 实 The geological parameters include soil density ρ. 土 The parameters include: water content w, porosity n, and permeability coefficient k; the structural design parameters of the tunnel boring machine include cutterhead outer diameter D1, segment outer diameter D2, annular thickness h, and segment compressive strength σ; the grouting slurry characteristic parameters include slurry density ρ. 浆 slurry viscosity η p The parameters include setting time (t), conductivity, and the real-time grouting rate, which is measured by electromagnetic flowmeters installed on each branch grouting pipeline. The real-time grouting pressure is measured by a corrosion-resistant pressure sensor near the shield tail section. The cumulative grouting volume is Q. 总 Obtained by the PLC control unit of the synchronous grouting system; The host operation data is provided by the shield tunneling machine main control PLC. The shield tunneling machine structural design parameters, geological parameters, and grouting slurry characteristic parameters are obtained from the shield tunneling machine design drawings, geological survey reports, and slurry test reports, respectively.

3. The automatic control system for synchronous grouting of a tunnel boring machine according to claim 1 or 2, characterized in that: The coupled correlation calculation module calculates the target grouting rate Q required for the current single-ring construction based on the multi-source data collected by the data acquisition and preprocessing module using the volume matching equation of tunneling speed-grouting rate. 目标 The initial value, and the calculated target grouting rate Q 目标 After unit conversion, the initial value was used to calculate the theoretical predicted grouting pump pressure P under the current working conditions using Bingham's fluid pressure formula. 预测 And based on the predicted grouting pump pressure value P 预测 Based on the benchmark, and taking into account the permissible pressure limit of the tunnel lining segments, the pressure required for effective grout diffusion, the permissible pressure of the equipment, the formation conditions, and the results of on-site injection calibration, the safe pressure range [P] was determined. 下限 P 上限 The real-time collected grouting pump pressure P 实 With [P] 下限 P 上限 Compare and correct Q in reverse based on the comparison results. 目标， This allows for the determination of the target grouting rate Q that matches the current tunnel boring speed v. 目标 Pressure control constraints and corresponding control commands.

4. The automatic control system for synchronous grouting of a tunnel boring machine according to claim 1 or 2, characterized in that: The effect feedback and parameter optimization module automatically stores construction data for each ring to establish a historical database. Based on the historical data, it optimizes the resistance coefficient and correction coefficient in the coupling equation through machine learning algorithms to improve the model's adaptability to different strata. The stored data includes tunneling speed, grouting rate, pressure, geological parameters, and filling effect. The effect feedback and parameter optimization module is equipped with a manual intervention interface, which allows operators to manually adjust the target parameter range based on their field experience. After adjustment, the model automatically learns and adapts.

5. The automatic control system for synchronous grouting of a tunnel boring machine according to claim 2, characterized in that: The synchronous grouting system control unit PLC and the shield tunneling main control PLC exchange data through the S7 communication protocol to coordinate and dynamically match the start and stop of tunneling speed and grouting rate.

6. The automatic control system for synchronous grouting of a tunnel boring machine according to claim 2, characterized in that: The installation position of the electromagnetic flowmeter meets the requirements that the upstream straight pipe section length is ≥5 times the diameter of the branch grouting pipe and the downstream straight pipe section length is ≥3 times the diameter of the branch grouting pipe. The electromagnetic flowmeter is installed horizontally with the electrode axis parallel to the horizon. The electromagnetic flowmeter and the pipeline are grounded separately with a grounding resistance ≤10Ω. Rubber shock-absorbing pads are installed between the electromagnetic flowmeter and the pipeline.

7. The automatic control system for synchronous grouting of a tunnel boring machine according to claim 3, characterized in that... Calculate the target grouting rate Q 目标 The volume matching equation for the tunneling speed-grouting rate is as follows: Q 目标 = k 地质 ×[π / 4×(D1²-D2²)×v×10 -6 ]×(1 + k 冗余 ) In the formula: Q 目标 is the target grouting rate, in L / min; v is the real-time tunneling speed of the tunnel boring machine, in mm / min; D1 is the outer diameter of the tunnel boring machine cutterhead, in mm; D2 is the outer diameter of the tunnel segment, in mm. π / 4 ×(D1²- D2²)×v×10 -6 It is the instantaneous annular volume generation rate, in L / min; k 地质 It is a geological correction factor, with 1.1 to 1.2 for soft soil and water-rich strata, 0.95 to 1.05 for hard rock and intact strata, and 1.2 to 1.3 for fractured strata, to compensate for slurry loss in highly permeable or fractured strata; k 冗余 It is the diffusion redundancy coefficient, which is taken as 0.05 to 0.1 and can be dynamically adjusted according to the grouting pressure feedback.

8. The automatic control system for synchronous grouting of a tunnel boring machine according to claim 3, characterized in that, P is calculated using Bingham's fluid pressure formula. 预测 The specific process is as follows: The calculated target grouting rate Q... 目标 Before substituting into the pressure formula, first convert the units to Q, i.e., Q = Q 目标 / 60000, where Q 目标 The unit of is L / min, and the unit of Q is m³ / s; P 预测 =ΔP1+ΔP2+P0 P 预测 =2L / R·(τ0+4η p Q / πR³)+2L 环空 / (r2-r1)·[τ0+ 4η p Q / (π(r2 4 -r1 4 ) / r2)] +P0 Introducing field correction factor k 阻力 That is, we get: P 预测 = k 阻力 ·{2L / R・[τ0+ 4η p Q / (πR³)] + 2L 环空 / (r2-r1) ·[τ0 + 4η p Q / (π(r2 4 -r1 4 ) / r2)]} + P0 In the above formula: P 预测 The pressure value of the grouting pump is to be predicted, in Pa, and is the parameter to be determined; Q is the target grouting rate. 目标 The pressure flow rate is calculated using unit conversion, with units of m³ / s. k 阻力 , is the field resistance correction coefficient, a dimensionless parameter, used to correct for pressure prediction deviations caused by pipeline resistance, shield tail annulus resistance, and changes in field construction conditions. P0 is the correction value for the starting pressure of slurry flow, in Pa, determined by field test; ΔP1 is the pressure loss along the pipeline, in Pa; ΔP2 is the pressure loss along the annulus, in Pa. τ0 is the slurry yield stress, in Pa; L is the length of the grouting pipeline, in meters; R is the inner radius of the grouting pipeline, in meters; η p The viscosity of the grout is expressed in Pa·s. L 环空 This is the effective length of the shield tail annulus, in meters, and is consistent with the length of the shield tail of the tunnel boring machine. r1 is the outer radius of the tunnel segment, in meters; r2 is the excavation radius of the stratum, in meters, and r2-r1 is the thickness of the annulus.

9. The automatic control system for synchronous grouting of a tunnel boring machine according to claim 3, characterized in that, The safe pressure range [P] 下限 P 上限 The calculation is as follows: P 下限 =max(P 有效注浆阈值 ,P 扩散下限 ,P 预测 ×(1-β)) P 上限 =min(P 管片允许压力 ,P 设备允许压力 ,P 地层允许压力 ,P 预测 ×(1+α)); Among them, P 下限 P is the lower limit of the safe pressure range. 上限 P represents the upper limit of the safe pressure range. 有效注浆阈值 To ensure the minimum pressure required for effective grout injection; P 扩散下限 The minimum pressure required to ensure effective diffusion of the slurry within the shield tail annulus; P 管片允许压力 P 设备允许压力 and P 地层允许压力 These represent the upper limits of the allowable pressure that the segment structure, grouting equipment, and construction stratum can withstand; P 预测 The predicted grouting pump pressure value is calculated based on Bingham's fluid pressure formula; α and β are the field-calibrated pressure allowable deviation coefficients, determined by field test injection, geological category, and historical construction data.

10. The automatic control system for synchronous grouting of a tunnel boring machine according to claim 3, characterized in that: The real-time collected grouting pump pressure P 实 With [P] 下限 P 上限 Compare and correct Q in reverse based on the comparison results. 目标 The process is as follows: The real-time collected grouting pump pressure P 实 With [P] 下限 P 上限 Comparison, When P 下限 ≤ P 实 ≤ P 上限 At that time, keep the current Q 目标 And based on the real-time grouting rate Q 实 With Q 目标 The deviation is finely adjusted using PID control. When P 实 > P 上限 When Q decreases 目标 Alternatively, reduce the opening of the proportional valve to increase the real-time grouting rate Q. 实 reduce; When P 实 < P 下限 Furthermore, when the cumulative grouting volume is insufficient, Q should be increased. 目标 Alternatively, increase the opening of the proportional valve to increase the real-time grouting rate Q. 实 improve; When there is prolonged low pressure and high flow, it is judged as an abnormality such as grout leakage or grout return and an alarm is triggered.

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