Sand gravel stratum jacking pipe jacking force-stratum resistance real-time matching control method

Abstract

The invention discloses a sand gravel stratum pipe jacking force-stratum resistance real-time matching control method, belongs to the technical field of underground engineering pipe jacking construction, and solves the technical problems of pipe clamping, ground upheaval or settlement easily caused by mismatching of jacking force and stratum resistance in a sand gravel stratum. According to the method, the jacking force is calculated by collecting the pressure of a jacking oil cylinder in real time, the torque of a cutter head, the rotating speed of a spiral conveyor and the soil outlet pressure are synchronously obtained, and a resistance sudden change area is recognized and target resistance is dynamically predicted based on the sudden change gradient of the torque-rotating speed ratio; the jacking speed, the grouting pressure and the rotating speed of the spiral conveyor are adjusted in a linkage mode according to the real-time deviation of the jacking force and the target resistance; and through grouting closed-loop control and unearthed pressure fluctuation analysis, a penetration abnormal area is judged, a penetration coefficient is corrected, and real-time dynamic matching of jacking system parameters and formation resistance is achieved. The method is mainly used for safe and efficient propulsion control of sand gravel stratum pipe jacking construction.

Description

Technical Field

[0001] The present invention relates to the technical field of underground engineering pipe jacking construction, and more particularly to a real-time matching control method of pipe jacking force and formation resistance in a gravel formation. Background Art

[0002] As a typical heterogeneous geological body, gravel and sand formations present significant engineering challenges for pipe jacking due to their random distribution. The highly heterogeneous structure created by the random distribution of gravel and sand particles in these formations results in dramatic fluctuations in both the cutterhead's cutting resistance and the pipe-soil friction (the frictional resistance generated by the relative motion between the outer wall of the pipe segment and the surrounding soil). In particular, the localized concentration of large-size gravel can cause instantaneous jumps in the jacking force during the jacking process, making traditional construction control methods ineffective in addressing these sudden changes.

[0003] Existing technologies for matching pipe jacking force with formation resistance rely primarily on feedback adjustment based on a single parameter, namely, jacking cylinder pressure. This approach fails to identify the fundamental variations in formation resistance caused by spatial variations in gravel distribution in sandy and gravel formations. When encountering sudden resistance changes, there is often a response lag of three to five rings. This lag can easily lead to overloading or underloading of the jacking system, potentially causing pipe jamming and even excessive surface settlement.

[0004] Existing grouting control strategies often rely on fixed pressure or linear velocity correlations, which are difficult to adapt to the highly variable permeability of gravel formations. The random distribution of seepage channels in gravel layers results in highly nonlinear slurry diffusion. Conventional grouting pressure settings often mismatch the actual permeability requirements of the formation, resulting in incomplete lubrication film formation or excessive slurry penetration.

[0005] Current technologies for controlling soil removal systems generally use a simple linear relationship between screw conveyor speed and jacking speed. However, in sandy and gravel formations, intermittent obstruction of the screw blades by gravel can significantly alter soil removal efficiency. Existing control models lack a coupled analysis mechanism for torque and speed, resulting in fluctuations in excavation pressure that often exceed safety thresholds.

[0006] Of particular note is the lack of predictive ability for areas with sudden changes in formation resistance. When the cutterhead encounters a gravel cluster, the sudden surge in jacking force often occurs 1-2 seconds after physical contact. However, it takes at least 5 seconds for the control system to detect and respond to the change in cylinder pressure. This time lag results in overshoots of 15%-25% of the design force in pipe jacking operations in gravel formations, creating a significant bottleneck in construction accuracy.

[0007] In summary, in pipe jacking construction in gravel formations, it is necessary to solve the problem of real-time and accurate matching of the jacking force and the formation resistance, especially the advance prediction and dynamic compensation of the resistance mutation zone, to eliminate the response lag and overshoot of traditional control methods, and avoid pipe jamming and uncontrolled surface settlement. Summary of the Invention

[0008] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0009] Another object of the present invention is to provide a real-time matching control method for the jacking force of a jacking pipe in a gravel formation and the formation resistance. The method identifies resistance mutations in real time and dynamically predicts the target formation resistance, thereby adjusting the jacking speed, grouting pressure and soil discharge parameters in a coordinated manner, effectively adapting to the sudden change characteristics of the gravel formation and reducing the risk of jacking pipe jamming and ground deformation.

[0010] In order to achieve these purposes and other advantages according to the present invention, a method for real-time matching control between the jacking force of a jacking pipe in a gravel formation and the formation resistance is provided, comprising: 1. A real-time matching control method for pipe jacking force and formation resistance in a gravel formation, characterized by comprising: S1, real-time collection of the pressure value P of the jacking cylinder of the pipe jacking machine c , calculate the current jacking force F c :F c =k1×P c ×A; S2. Synchronously obtain the cutter head torque T and screw conveyor speed N s and excavation pressure P s , based on the coupling effect of gravel on the cutter head and screw conveyor in the sand and gravel formation, calculate T and N s The mutation gradient M: M = ▽ (T / N s ), when the mutation gradient M exceeds the preset threshold N, it is determined to be a resistance mutation zone of the gravel formation; S3. When it is determined to be a sand-gravel formation resistance mutation zone, dynamically predict the target formation resistance F r :F r =F0+k2(MN); S4, according to the current jacking force F c and target formation resistance F r Real-time deviation value △F: △F=F c -F r Real-time adjustment of the jacking system: like ≤B, then maintain the current jacking parameters; if △F>B, then execute: reduce the jacking speed V and increase the grouting pressure P in conjunction j , press N s=λ×V to reduce the screw conveyor speed; if △F<-B, then execute: increase the jacking speed V and reduce the grouting pressure P in conjunction j , press N s =λ×V to increase the speed of the screw conveyor; S5, P fed back by grouting pressure sensor j Actual value, closed loop control grouting pump output, so that P j And the jacking speed V satisfies: P j =f×V 0.5 ; Real-time according to the excavation pressure P s The standard deviation σ s , if σ s >σ0, it is determined to be an abnormal permeability zone of gravel formation, and the permeability coefficient of gravel formation is dynamically corrected: f'=f+k3(σ s -σ0); Where A is the effective area of ​​the cylinder, m 2 ; k1 is the system efficiency coefficient, which is obtained from the cylinder no-load propulsion calibration test and has a value of 0.85~0.95; k2 is the particle size influencing factor based on the sand and gravel grading calibration, k2=0.3d 1.5 , d Maximum gravel particle size of the gravel layer, mm; F0 is the design basis resistance, kN; λ is the soil discharge efficiency coefficient of the gravel stratum, rpm·min / mm, λ=Q / 1.4S, where Q is the theoretical displacement of the screw conveyor, m 3 / min; S is the cross-sectional area of ​​the pipe segment, m 2 ; B is the resistance tolerance, kN, which is 5%~10% of F0; f is the permeability coefficient of the sand-gravel stratum; σ0 is the statistical standard deviation of the excavation pressure of the test section of the homogeneous sand-gravel stratum, MPa; k3 is the permeability correction factor, MPa -1 ·s -0.5 .

[0011] Preferably, the permeability correction factor k3 is calibrated by performing the following operations in the sand and gravel formation test: fixing the jacking speed V to 20 mm / min; starting from the initial grouting pressure P j0 Start to increase the grouting pressure step by step and record the standard deviation of the unearthed pressure σ after each increase in grouting pressure s ; According to the formula = Calculate the values ​​for each working condition; take the arithmetic mean of k3 for each working condition as the final calibration value of k3.

[0012] Preferably, in step S3, if the deviation value of the jacking force measured for three consecutive rings is >15%, the dynamic correction of the particle size influencing factor k2 based on the sand and gravel grading calibration is started: k2'= k2+ , M i -N>0.1s -1 And F c,i -F0>50kN; where F c,i The first is the pressure value of the jacking cylinder of the i-ring pipe jacking machine; M i For the i-th ring T and N s mutation gradient.

[0013] Preferably, in step S4, when the top pipe is in a curved section and the curvature radius R is less than 500D, P j The relationship between P and the jacking speed V is modified to: j =f×V 0.5 ; Wherein, D is the outer diameter of the jacking pipe segment, m; k4 is the curve segment compensation coefficient, which is 0.02θ; θ is the axis deviation angle between pipe segments during curve jacking, in degrees.

[0014] Preferably, the method for controlling the real-time matching of the jacking force and the formation resistance of the jacking pipe in the gravel formation further comprises performing a friction resistance reset operation every time 100 rings are advanced: Pause jacking and maintain grouting pressure P j 0.8MPa, lasting 5min; The pipe section is slightly retracted by 20mm to release the interface shear stress; When restarting the jacking, the initial speed is reduced to 60% of the speed before the pause and restored in steps of 10% / min.

[0015] Preferably, the k2, k3 and f' after each correction are stored according to the classification of the geological radar scanning results; when the geological radar identifies similar stratum features, the historical optimal parameter combination is automatically called for preloading.

[0016] Preferably, the mechanism for obtaining the historical optimal parameter combination is as follows: Real-time acquisition of geological radar scanning signals to extract characteristic signals of gravel formations: dielectric constant ρ, reflection coefficient φ, and 0.2m scale reflection capacity ratio P 200 ; According to the parameter combination effect evaluation function S=0.5× , calculate the parameter combination with the smallest S as the historical optimal parameter combination; When the radar identifies that the characteristic signals of the gravel formation are the same, the historical optimal parameter combination under the same gravel formation is automatically loaded; The benchmark value of jacking force fluctuation is the standard deviation of the jacking force in the test section.

[0017] Preferably, when the fluctuation amplitude of the cutterhead speed exceeds ±5% of the set value for 10 consecutive seconds, the target formation resistance prediction value in step S3 is adjusted to F r ':F r '=F r ×8%.

[0018] The present invention has at least the following beneficial effects: First, the present invention can accurately adapt to sudden changes in gravel resistance in sandy and gravel formations. By calculating the sudden gradient of the cutterhead torque and the screw conveyor speed in real time, it can dynamically predict the resistance of the target formation, effectively addressing sudden changes in gravel resistance in sandy and gravel formations and reducing the risk of pipe jamming. Secondly, the present invention can realize intelligent correction of permeability anomalies. Based on the calibration of the permeability correction factor k3 based on the step grouting test, the permeability coefficient is corrected in real time in combination with the standard deviation of the unearthed pressure, which significantly improves the control accuracy of the grouting pressure in permeable sand and gravel formations and reduces formation disturbance. Thirdly, the present invention can also realize adaptive adaptation to gradation changes. When the continuous jacking deviation exceeds the limit, the particle size influencing factor k2 is automatically corrected, and the resistance prediction model is dynamically optimized to adapt to the spatial variability of sand and gravel gradation, avoiding uncontrolled jacking force caused by error accumulation. Fourthly, the present invention introduces a pipe segment deviation angle compensation coefficient when the curvature radius of the curved section is small, corrects the grouting pressure-jacking speed relationship, effectively compensates for the additional resistance of the curved jacking, and suppresses the surface settlement caused by formation loss; Fifth, the present invention regularly performs micro-retreat of pipe joints and grouting to maintain pressure, thereby releasing interface shear stress, resetting pipe-soil friction, maintaining long-term stable operation of the jacking system and extending the life of the equipment; Sixth, the present invention also realizes automatic preloading of k2, k3 and f' parameters by matching historical optimal parameters with geological radar characteristics, thereby improving the construction efficiency of similar strata and reducing trial and error costs.

[0019] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure is a flow chart of the real-time matching control method of the jacking force and formation resistance of the jacking pipe in the gravel formation according to the present invention. DETAILED DESCRIPTION

[0021] The present invention will be described in further detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0022] It should be understood that terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0023] like Figure 1 The present invention provides a real-time matching control method for pipe jacking force and formation resistance in a gravel formation, comprising: A real-time matching control method for pipe jacking force and formation resistance in a gravel formation is characterized by comprising: S1, real-time collection of the pressure value P of the jacking cylinder of the pipe jacking machine c , calculate the current jacking force F c :F c =k1×P c ×A; S2. Synchronously obtain the cutter head torque T and screw conveyor speed N s and excavation pressure P s , based on the coupling effect of gravel on the cutter head and screw conveyor in sandy gravel formation, calculate T and N s The mutation gradient M: M = ▽ (T / N s ), when the mutation gradient M exceeds the preset threshold N, it is determined to be a resistance mutation zone of the gravel formation; S3. When it is determined to be a sand-gravel formation resistance mutation zone, dynamically predict the target formation resistance F r :F r =F0+k2(MN); S4, according to the current jacking force F c and target formation resistance F r Real-time deviation value △F: △F=F c -F r Real-time adjustment of the jacking system: like ≤B, then maintain the current jacking parameters; if △F>B, then execute: reduce the jacking speed V and increase the grouting pressure P in conjunction j , press N s =λ×V to reduce the screw conveyor speed; if △F<-B, then execute: increase the jacking speed V and reduce the grouting pressure P in conjunction j , press N s =λ×V to increase the speed of the screw conveyor; S5, P fed back by grouting pressure sensor j Actual value, closed loop control grouting pump output, so that P j And the jacking speed V satisfies: P j =f×V 0.5 ; Real-time according to the excavation pressure P s The standard deviation σ s , if σ s>σ0, it is determined to be an abnormal permeability zone of gravel formation, and the permeability coefficient of gravel formation is dynamically corrected: f'=f+k3(σ s -σ0); Where A is the effective area of ​​the cylinder, m 2 ; k1 is the system efficiency coefficient, which is obtained from the cylinder no-load propulsion calibration test and has a value of 0.85~0.95; k2 is the particle size influencing factor based on the sand and gravel grading calibration, k2=0.3d 1.5 , d Maximum gravel particle size of the gravel layer, mm; F0 is the design basis resistance, kN; λ is the soil discharge efficiency coefficient of the gravel stratum, rpm·min / mm, λ=Q / 1.4S, where Q is the theoretical displacement of the screw conveyor, m 3 / min; S is the cross-sectional area of ​​the pipe segment, m 2 ; B is the resistance tolerance, kN, which is 5%~10% of F0; f is the permeability coefficient of the sand-gravel stratum; σ0 is the statistical standard deviation of the excavation pressure of the test section of the homogeneous sand-gravel stratum, MPa; k3 is the permeability correction factor, MPa -1 ·s -0.5 .

[0024] The above technical solution senses changes in formation conditions in real time, especially sudden changes in resistance and permeability anomalies, and dynamically predicts the target formation resistance based on changes in formation conditions, thereby accurately adjusting the parameters of the jacking system to ensure real-time matching of the jacking force and formation resistance, avoiding problems such as insufficient jacking force leading to pipe sticking or excessive jacking force leading to ground uplift and equipment overload.

[0025] The above technical solution includes real-time monitoring and calculation of the jacking force, using a pressure sensor to collect the pressure value P of the main jacking cylinder of the pipe jacking machine in real time. c (Unit: MPa), and combined with the effective area of ​​the cylinder A (unit: m2) and the system efficiency coefficient k1 (experience value range: 0.85~0.95) to calculate the current actual jacking force F c (Unit: kN), F c =k1×P c ×A. k1 is determined based on the specific equipment through no-load cylinder thrust calibration testing, taking into account operational system losses and friction losses. The pressure sensor should be a high-precision pressure sensor, such as the Honeywell ST series. It should be installed in the main jacking cylinder's oil inlet and / or return line, close to the cylinder body, to ensure that the pressure measurement accurately reflects the cylinder thrust.

[0026] The above technical solution also includes the step of identifying the sudden change area of ​​formation resistance, and synchronously collecting the cutter head drive torque T (unit: kN·m) and the screw conveyor speed N s (Unit: rpm). Calculate the ratio of the two, T / N s The mutation gradient M (i.e., the gradient operator ▽(T / N s )). When M exceeds the preset threshold N, it is determined that the gravel formation has entered the resistance mutation zone. This mechanism is based on the coupled blocking effect of gravel in the gravel formation on the cutterhead cutting (torque) and the screw conveyor slag discharge (speed). The cutterhead drive torque T is obtained by the cutterhead torque sensor installed on the drive end (motor side) or output end (cutterhead measurement) of the cutterhead drive spindle. The screw conveyor speed N is s The excavation pressure P is measured by the screw conveyor speed sensor installed on the screw conveyor drive motor shaft or the reducer output shaft. s The pressure is measured by the unearthed pressure sensor installed in the pressure chamber of the unearthed outlet (slag outlet) of the screw conveyor. Based on the identification of the stratum resistance mutation zone, the dynamic prediction of the target stratum resistance is further carried out. Once the resistance mutation zone (M>N) is identified, the dynamic prediction of the target stratum resistance is immediately carried out according to the mutation degree (M-N) and the particle size influence factor k2 (k2=0.3d based on the sand and gravel grading calibration) 1.5 , d is the maximum gravel particle size (mm), based on the benchmark design resistance F0 (unit: kN), the current target formation resistance Fr is dynamically predicted, F r = F0 + k2 (MN) (unit: kN). The k2 formula reflects the significant amplification effect of large-size gravel on the resistance increment. The d value must be determined through geological exploration (typical range: 20mm to 100mm+). F0 is determined based on the geological report and design calculations. N (the mutation threshold) must be calibrated during the test push section, during which the pipe jacking machine is operated at a moderate, stable propulsion speed. Maintain relatively constant key parameters such as cutterhead speed and grouting pressure. Record the ratio of cutterhead torque to screw conveyor speed and set a safety threshold N based on its maximum variation, generally not exceeding 1.5 times the maximum variation.

[0027] The above technical solution also includes real-time control of the jacking system and calculation of the current jacking force F c With the target resistance F r The real-time deviation △F, if ≤B (B is the resistance tolerance, which is 5%~10% of F0), then maintain the current jacking parameters. If △F>B, the jacking force is too large, then reduce the jacking speed V and increase the grouting pressure P in conjunction. j , press N s=λ×V Reduce the screw conveyor speed, λ is the soil discharge efficiency coefficient (λ = Q / (1.4 ×S), Q is the theoretical displacement of the screw conveyor m 3 / min, S is the cross-sectional area of ​​the pipe segment m 2 ), ensure that the amount of soil discharged matches the advancement speed to avoid over-discharge or under-discharge. If △F<-B, the jacking force is insufficient, then execute: increase the jacking speed V, and reduce the grouting pressure P in conjunction. j , press N s =λ×V to increase the screw conveyor speed. Further, the grouting pressure sensor (P j ) feedback actual value, close loop control grouting pump output, so that P j The relationship P is satisfied with the jacking speed V j =f×V 0.5 (f is the initial permeability coefficient of the sand and gravel formation). The purpose is to dynamically adjust the slurry injection pressure according to the advancement speed to optimize the friction reduction effect. Real-time calculation of the earth pressure P s The standard deviation σ s (reflecting the fluctuation degree of the soil discharge pressure), if σ s >σ0 (σ0 is the statistical standard deviation of the homogeneous formation test section), it is determined to be an abnormal permeability area (such as the presence of lenses, interlayers, etc.), and the dynamic correction permeability coefficient f' = f + k3× (σs - σ0) (k3 is the permeability correction factor, unit MPa -1 ·s -0.5 ). The corrected f' is used to update the grouting pressure target value formula P j =f×V 0.5 .

[0028] According to the above technical solution, a specific workflow of the present invention is as follows: Initial and Continuous Monitoring: The pipe jacking machine starts advancing in gravel and sandy ground. The control system continuously collects key data at a high frequency: main jacking cylinder pressure, cutterhead drive torque, screw conveyor speed, and excavation pressure. The system calculates the actual jacking force and the ratio of cutterhead torque to screw conveyor speed in real time.

[0029] Mutation Identification and Target Setting: When the system detects a sudden and dramatic increase in the rate of change in the torque / speed ratio that exceeds a preset threshold (e.g., the cutterhead encountering a dense mass of large rocks causes a surge in torque and a decrease in speed), it immediately identifies the entry into a resistance mutation zone. Based on the severity of this mutation and the known maximum rock size in the formation, the system dynamically calculates and sets a higher target resistance value based on the basic design resistance value, representing the required thrust force in this challenging section.

[0030] Deviation Analysis and Parameter Adjustment: The system immediately compares the current actual jacking force with the newly set target resistance value. If the actual jacking force is significantly below the target (a significant negative deviation could cause the machine to become stuck), the control system immediately implements adjustments: increasing the thrust speed to increase the thrust; simultaneously, the grouting pressure is linked to the speed change (to avoid excessive grouting when thrust is insufficient); and the screw conveyor speed is automatically increased to match the increased thrust speed, ensuring smooth excavation. This series of actions is designed to rapidly increase the actual jacking force to approach the target value.

[0031] Permeability Monitoring and Correction: During the advancement process, the system continuously monitors the stability of the excavation pressure. If the excavation pressure fluctuates significantly (with a standard deviation significantly greater than the baseline value for a normally uniform formation), this indicates a localized anomaly in the formation permeability (such as a highly permeable sand layer). Based on the magnitude of the anomaly, the system dynamically adjusts the permeability coefficient used to calculate the grouting pressure target (increasing the coefficient in permeable areas). The updated permeability coefficient takes effect immediately, and the closed-loop grouting control system adjusts the grouting pump pressure output accordingly to ensure that the slurry injection pressure adapts to the new formation conditions and maintains effective lubrication and formation support.

[0032] Stable Advancement: After adjustments, when the actual jacking force returns to within the allowable tolerance of the target resistance value, the system maintains the current combination of parameters—such as thrust speed, grouting pressure, and screw conveyor speed—to achieve stable and safe continuous jacking. This closed-loop process of perception-prediction-decision-adjustment operates continuously, ensuring the pipe jacking machine's intelligent and adaptive response to the complex and changing characteristics of sandy and gravel formations.

[0033] The above technical solution can identify sudden changes in jacking resistance in sandy and gravel formations caused by large-size gravel or dense layers in real time. Once the risk of a sudden change is identified, the system predicts the target resistance value required for that section in advance and proactively and collaboratively adjusts the jacking speed, grouting pressure, and soil discharge rate. This effectively avoids the problems encountered in traditional methods, such as insufficient jacking force due to sudden increases in resistance (causing pipe jams and ground collapse) or excessive jacking force due to blind jacking (causing pipe joint damage, ground heave, and equipment overload). This significantly improves the safety and continuity of construction in complex sandy and gravel formations, reducing unplanned downtime. By monitoring the fluctuation characteristics of the excavation pressure in real time, it intelligently identifies local anomalies in the formation permeability (such as seepage channels or water-repellent interlayers). Upon detection, the key grouting pressure control parameter (permeability coefficient) is dynamically adjusted and the grouting pressure target value is updated in real time. This enables the grouting system to adapt to changes in formation permeability: automatically increasing grouting pressure in high-permeability areas to ensure an effective slurry jacket, while preventing excessive pressure from splitting the formation in low-permeability areas. Closed-loop control ensures precise regulation of grouting pressure, maximizing the slurry's friction-reducing effect, effectively supporting the excavation face and controlling deformation in the surrounding ground, minimizing the risk of surface subsidence and slurry loss. An intelligent linkage mechanism is also established between propulsion speed, grouting pressure, and screw conveyor speed. When adjusting the core parameter, propulsion speed, the grouting pressure and soil discharge speed automatically coordinate according to a pre-set engineering logic: grouting pressure dynamically adjusts with the square root of speed, and soil discharge speed is proportional to propulsion speed. This ensures that soil discharge volume always matches propulsion volume (preventing over-excavation or under-excavation) and that grouting pressure matches propulsion speed and ground characteristics (optimizing lubrication and ground stability). This ensures that the three core functions of the pipe jacking system—thrust, soil discharge, and friction reduction—operate efficiently and synergistically even under dynamic ground conditions, significantly improving the controllability, stability, and overall efficiency of the construction process while reducing over-reliance on operator experience.

[0034] In one of the technical solutions, the permeability correction factor k3 is calibrated by performing the following operations in the sand and gravel formation test: fixing the jacking speed V to 20 mm / min; starting from the initial grouting pressure P j0 Start to increase the grouting pressure step by step and record the standard deviation of the unearthed pressure σ after each increase in grouting pressure s ; According to the formula = Calculate the values ​​for each working condition; take the arithmetic mean of k3 for each working condition as the final calibration value of k3.

[0035] The above technical solution quantifies the sensitivity of the permeability coefficient correction by actively changing the grouting pressure and observing the formation response (excavation pressure fluctuation) under controllable test conditions. A homogeneous sand and gravel formation test section was selected for calibration. The jacking speed V was strictly fixed at 20 mm / min, eliminating the influence of the advancement speed change on the excavation pressure fluctuation, ensuring that the observed fluctuation mainly reflects the relationship between the grouting pressure change and the formation permeability. From a low initial grouting pressure (P j0 ) starts. Then, the grouting pressure is gradually increased according to the preset and controllable step amplitude. After each pressure increase, it is necessary to run it steadily for a short period of time (for example, a few minutes) to allow the formation response (excavation pressure) to reach a new stable state. After each grouting pressure increase and stabilization, the system continuously monitors the pressure at the screw conveyor outlet (P s Calculate and record the standard deviation (σ) of the excavation pressure Ps under the steady state. s ). Standard deviation σ s It quantifies the fluctuation degree of the unearthed pressure and is a direct indicator of the sensitivity of the formation permeability to the change of grouting pressure. The greater the permeability change, the greater the σ s P j The more sensitive it is to changes in pressure. For each grouting pressure increase operation, the system will calculate a temporary k3 value. This temporary k3 value represents the proportional relationship between the grouting pressure adjustment amount corresponding to the unit excavation pressure fluctuation change under this specific pressure change, while taking into account the influence of the fixed jacking speed. After completing all the preset grouting pressure step-up operations, the system will obtain multiple temporary k3 values ​​(corresponding to different pressure change conditions). Finally, the arithmetic mean of all these temporary k3 values ​​is taken as the final value of the calibrated permeability correction factor k3 used for subsequent formal jacking control. The purpose of taking the average is to obtain a more robust and representative comprehensive indicator.

[0036] According to the above technical solution, a specific workflow is as follows: During the early stage of the project's trial push (a geologically uniform sand and gravel formation), the pipe jacking machine's push speed is set and stabilized at 20 mm / min. A low initial grouting pressure value is set (e.g., 0.01-0.1 MPa). The control system is ready to record the grouting pressure and excavation pressure data. Advancement begins. After stabilizing at the initial grouting pressure for a few minutes, the system records the excavation pressure data at this time and calculates its standard deviation σ. s1 Then, increase the grouting pressure by a predetermined step (e.g., increase by 0.1 MPa). Run the system stably for a few minutes again, record the unearthed pressure data under the new pressure, and calculate its standard deviation σ s2 Repeat this process and record σ s3For each pressure increase, the system records the change in grouting pressure and the corresponding change in the standard deviation of the unearthed pressure. Combined with a fixed jacking speed, the system calculates a temporary k3 value that represents the sensitivity of the correction under this pressure change. The system further calculates the arithmetic mean of multiple temporary branches as the calibrated permeability correction factor. In subsequent formal jacking, when the system detects permeability anomalies and needs to correct the permeability coefficient f, it uses this calibrated k3 value for calculation.

[0037] This technical solution provides a standardized calibration process based on field data. By actively varying the input (grouting pressure) under controlled conditions (fixed velocity, stepped pressure increase) and precisely measuring the output response (excavation pressure fluctuations), this method objectively quantifies the sensitivity of permeability changes in specific sand and gravel formations to grouting pressure adjustments. This significantly improves the accuracy and reliability of the k3 value, thereby ensuring the predictive accuracy and control effectiveness of the permeability anomaly correction logic. Eliminating subjectivity and uncertainty, this technical solution provides a repeatable and verifiable engineering test method, enabling the determination of the k3 value based on actual formation response data from specific projects. This not only reduces over-reliance on operator experience but, more importantly, significantly enhances the adaptability of the entire control system to diverse sand and gravel formation conditions, ensuring consistent and scientific application of the control strategy across projects and enabling faster and more accurate calculation of the grouting pressure target appropriate for the permeability characteristics of the new formation.

[0038] In one of the technical solutions, in step S3, if the deviation value of the jacking force measured for three consecutive rings is >15%, the dynamic correction of the particle size influencing factor k2 based on the sand and gravel grading calibration is started: k2'= k2+ , M i -N>0.1s −1 And F c,i -F0>50kN; where F c,i The first is the pressure value of the jacking cylinder of the i-ring pipe jacking machine; M i For the i-th ring T and N s mutation gradient.

[0039] The above technical solution addresses the problem of prediction errors caused by the k2 value initially calibrated based on the maximum gravel particle size when the actual formation gradation deviates from the expected one. Its core principle is to reverse-calibrate the k2 value using recent actual construction data when the system continuously monitors significant and persistent deviations in the jacking force prediction, thereby improving the accuracy of subsequent resistance predictions. During the advancement process, the system continuously monitors the relative deviation between the actual jacking force and the target resistance prediction for each ring (usually a segment). If the deviation for three consecutive rings exceeds a significant threshold of 15%, and two additional conditions are met: the resistance gradient detected within that ring (i.e., the amount by which the gradient exceeds the threshold) is sufficiently large, and the actual jacking force exceeds the foundation resistance by a significant amount, the system determines that the initial k2 value may need to be adjusted. At this point, the system automatically triggers a dynamic k2 correction program. This program extracts data from these three rings that meet the following criteria: the amount by which the actual jacking force exceeds the foundation resistance for each ring, and the amount by which the corresponding resistance gradient exceeds the threshold. Using these actual data points, the system calculates a provisional k2 value for each ring, implicit in the data, that better reflects the actual response of the formation to the sudden change. (The calculation principle is: the actual resistance increment divided by the sudden change intensity increment reflects the true response strength of the formation to the sudden change in that ring.) Finally, the system compares these three provisional k2 values ​​with the original k2 value, takes the average of the differences, and superimposes this average on the original k2 value to obtain a new, corrected particle size influence factor k2', calibrated with actual field data. This corrected k2' is used in the target resistance prediction calculation for subsequent advancement rings. The maximum gravel particle size d provided by geological exploration is an estimate for the design phase; the gravel gradation distribution encountered in actual construction may be more complex and variable. When significant prediction deviations occur over multiple consecutive rings, it indicates that the initial k2 setting no longer accurately reflects the true response strength of the formation to the sudden change in resistance. By using the latest, reliable measured data (resistance increment and sudden change intensity) to reversely calculate and correct the k2 value, the system can dynamically adapt to changes in actual formation gradation, significantly improving subsequent target resistance F. r The accuracy of the prediction makes the jacking force control more practical.

[0040] The heterogeneity of sand and gravel formations presents a significant challenge for construction control. The initially calibrated k² value can become invalid due to localized formation variations (e.g., dense gravel zones, shifts in particle size distribution). The conditionally triggered correction mechanism (continuous exceedances + significant mutations) established in this technical solution allows for timely intervention when prediction deviations accumulate and become significant, preventing the continued deterioration of control effectiveness due to parameter inaccuracies (e.g., chronically insufficient or excessive jacking force). This effectively adds an adaptive feedback loop for the key geological parameter k² to the control system, significantly reducing the absolute reliance on the accuracy of initial geological exploration and enhancing the long-term effectiveness and reliability of the entire control method in complex, unknown formations.

[0041] In one of the technical solutions, in step S4, when the top pipe is in a curved section and the curvature radius R is less than 500D, P j The relationship between P and the jacking speed V is modified to: j =f×V 0.5 ; Wherein, D is the outer diameter of the jacking pipe segment, m; k4 is the curve segment compensation coefficient, which is 0.02θ; θ is the axis deviation angle between pipe segments during curve jacking, in degrees.

[0042] To address the unique operating conditions of pipe jacking in curved sections, the aforementioned technical solution incorporates an adaptive curvature radius compensation mechanism into the existing grouting pressure control logic. Its core principle is to dynamically sense the curvature of the pipe jacking trajectory and intelligently adjust the grouting pressure to offset the additional resistance created by the curved section. The system continuously monitors the curvature radius of the current section of the pipe jacking machine (obtained through the guidance system or pipe segment attitude sensors). When the curvature radius is less than 500 times the pipe segment's outer diameter (R < 500D), it determines that a sharp curve has been entered and triggers compensation mode. Based on the actual axis deviation angle θ between the pipe segments (measured in real time by the articulation angle sensor), a curve compensation coefficient k4 (k4 = 0.02θ) is proportionally generated. This coefficient directly reflects the lateral compression strength during pipe segment correction. A compensation term inversely proportional to the curvature radius and proportional to the square of the pipe diameter is added to the existing grouting pressure baseline value (proportional to the square root of the velocity). The smaller the curvature (the sharper the turn) or the larger the pipe diameter, the more significant the increase in compensation pressure, thereby specifically offsetting the additional frictional resistance of the soil outside the curved section to the pipe wall.

[0043] The lateral soil extrusion caused by pipe segment correction in sharp curve sections can significantly increase frictional resistance. Traditional uniform grouting strategies are prone to causing a surge in jacking force or pipe segment jamming. The above technical solution uses dual sensing of curvature radius and deflection angle to establish an intelligent mapping between grouting pressure and spatial trajectory, specifically compensating for the additional resistance on the outside of the curve, effectively avoiding uncontrolled jacking force in the curve section, and ensuring that the pipe segment smoothly turns along the designed trajectory. The stress distribution of the soil in the curved section is complex, and the standard grouting pressure may not be sufficient to form an effective lubricating mud film on the outside of the curve. This solution uses adaptive boost compensation to ensure that the outer periphery of the pipe wall, especially the stress concentration area, is always covered with sufficient mud, significantly reducing direct friction between the pipe segment and the soil, reducing the shear disturbance of the stratum caused by correction, and fundamentally suppressing the risks of ground subsidence or pipe segment deformation common in curved sections. The above technical solution also incorporates spatial geometric parameters into the real-time control closed loop, making the grouting system three-dimensional path adaptable. It forms multi-dimensional synergy with the permeability correction and resistance mutation correction of straight segments, completely covering the linear / nonlinear advancement scenarios of pipe jacking in gravel formations, and significantly improving the control accuracy and equipment safety of complex trajectory construction.

[0044] In one of the technical solutions, the method for controlling the real-time matching of the jacking force and the formation resistance of the jacking pipe in the gravel formation further includes performing a friction reset operation every time 100 rings are advanced: Pause jacking and maintain grouting pressure P j 0.8MPa, lasting 5min; The pipe section is slightly retracted by 20mm to release the interface shear stress; When restarting the jacking, the initial speed is reduced to 60% of the speed before the pause and restored in steps of 10% / min.

[0045] The above-mentioned technical solution actively eliminates abnormal interface shear forces accumulated during long-term jacking due to local failure of the mud sleeve or stress redistribution in gravel formations by periodically performing friction reset operations (pausing jacking every 100 rings and implementing pressure-maintaining lubrication, slight retreat of the pipe joint, and step-by-step restart). During the pressure-maintaining stage, maintaining a grouting pressure of 0.8 MPa can repair weak mud films, slightly retreating 20 mm can release the locking stress of the pipe soil, and step-by-step restart (initial speed 60% + 10% / min recovery) can avoid a sudden increase in shear stress, thereby significantly reducing the time-varying friction fluctuations of the jacking system, preventing the risk of pipe joint jamming or ground subsidence caused by sudden surges in jacking force, and improving the stability and safety of continuous jacking construction in long-distance gravel formations.

[0046] In one technical solution, the corrected k2, k3, and f' are stored categorized by geological radar scan results. When the geological radar identifies similar formation features, the historical optimal parameter combination is automatically called for pre-loading. By binding and storing the dynamically corrected key parameters (k2, k3, f') with the formation feature map scanned by the geological radar, a formation feature-control parameter knowledge base is established. When the jacking pipe advances to a similar formation section identified by the geological radar, the system automatically calls for the historical optimal parameter combination for pre-loading, achieving self-migration of control parameters driven by formation characteristics. This significantly reduces repeated calibration steps and avoids the risk of secondary trial and error under the same formation conditions. The response speed of the jacking force-resistance matching in complex formations is increased by more than 40%. At the same time, control accuracy is guaranteed by reusing verified parameter combinations, effectively preventing jacking force fluctuations and formation disturbances caused by parameter adaptation lags.

[0047] In one of the technical solutions, the mechanism for obtaining the historical optimal parameter combination is as follows: Real-time acquisition of geological radar scanning signals to extract characteristic signals of gravel formations: dielectric constant ρ, reflection coefficient φ, and 0.2m scale reflection capacity ratio P 200 ; According to the parameter combination effect evaluation function S=0.5× , calculate the parameter combination with the smallest S as the historical optimal parameter combination; When the radar identifies that the characteristic signals of the gravel formation are the same, the historical optimal parameter combination under the same gravel formation is automatically loaded; The benchmark value of jacking force fluctuation is the standard deviation of the jacking force in the test section.

[0048] The above technical solution establishes an intelligent matching library between formation characteristics and control parameters. It quantifies formation properties through geological radar scanning and selects optimal control parameters based on a multi-dimensional evaluation of construction performance. This implementation involves three steps: First, real-time geological radar signals are collected to analyze three key indicators of sand and gravel formations: dielectric constant (reflecting density), reflection coefficient (characterizing interfacial impedance), and 0.2-meter-scale reflectivity ratio (indicating gravel distribution uniformity), forming a unique formation fingerprint. Second, a comprehensive performance score (S) is calculated for each parameter combination (k2 / k3 / f') used in each formation section. This score incorporates three key indicators: jacking force fluctuation rate (weighted 50%, compared to the baseline value of the trial section), surface settlement (weighted 30%, compared to the design allowable value), and grouting consumption (weighted 20%, compared to the theoretical design value). The minimum S value is marked as the optimal parameter combination for the current formation. When the radar scans a new section that matches a historical formation fingerprint, the optimal parameter combination (k2 / k3 / f') corresponding to that fingerprint is automatically retrieved and preloaded into the control system, bypassing the trial-and-error process and directly applying the verified optimal configuration.

[0049] This technical solution breaks through the traditional parameter setting model that relies on manual experience. Through precise mapping of radar characteristics and multi-objective assessment, it converts the physical characteristics of the formation into quantifiable control parameters, giving the jacking system geologically adaptive intelligence. When the radar identifies a similar formation fingerprint, it automatically reuses the historically optimal parameter combination, avoiding repeated debugging under the same geological conditions, shortening the parameter adaptation time in new sections, and significantly improving the efficiency of continuous construction in complex formations. The multi-objective evaluation function (S) coordinates jacking force stability, settlement control, and grouting efficiency, ensuring that the parameter group used takes into account both construction safety (suppressing sudden changes in jacking force and surface settlement) and resource optimization (avoiding grouting waste), achieving refined control of long-distance pipe jacking at the system level.

[0050] In one technical solution, if the cutterhead speed fluctuation exceeds ±5% of the set value for 10 consecutive seconds, the target formation resistance prediction value in step S3 is adjusted to Fr': Fr' = Fr × 8%. By monitoring the cutterhead speed stability in real time (if the fluctuation exceeds ±5% for 10 consecutive seconds), the target resistance prediction value is proactively increased by 8%. This preemptively compensates for transient increases in cutting resistance caused by uneven gravel distribution or localized hard rock, effectively avoiding the risk of equipment overload or jamming caused by sudden changes in cutterhead torque. It also provides a buffer margin for the jacking system, ensuring the continuity and stability of driving power output in complex formations.

[0051] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A real-time matching control method for pipe jacking force and formation resistance in gravel formations, characterized in that: include: S1, real-time collection of the pressure value P of the jacking cylinder of the pipe jacking machine c , calculate the current jacking force F c :F c =k1×P c ×A; S2. Synchronously obtain the cutter head torque T and screw conveyor speed N s and excavation pressure P s , based on the coupling effect of gravel on the cutter head and screw conveyor in the sand and gravel formation, calculate T and N s The mutation gradient M: M = ▽ (T / N s ), when the mutation gradient M exceeds the preset threshold N, it is determined to be a resistance mutation zone of the gravel formation; S3. When it is determined to be a sand-gravel formation resistance mutation zone, dynamically predict the target formation resistance F r :F r =F0+k2(MN); S4, according to the current jacking force F c and target formation resistance F r Real-time deviation value △F: △F=F c -F r Real-time adjustment of the jacking system: like ≤B, then maintain the current jacking parameters; if △F>B, then execute: reduce the jacking speed V and increase the grouting pressure P in conjunction j , press N s =λ×V to reduce the screw conveyor speed; if △F<-B, then execute: increase the jacking speed V and reduce the grouting pressure P in conjunction j , press N s =λ×V to increase the speed of the screw conveyor; S5, P fed back by grouting pressure sensor j Actual value, closed loop control grouting pump output, so that P j And the jacking speed V satisfies: P j =f×V 0.5 ; Real-time according to the excavation pressure P s The standard deviation σ s , if σ s >σ0, it is determined to be an abnormal permeability zone of gravel formation, and the permeability coefficient of gravel formation is dynamically corrected: f'=f+k3(σ s -σ0); Where A is the effective area of ​​the cylinder, m 2 ; k1 is the system efficiency coefficient, which is obtained from the cylinder no-load propulsion calibration test and has a value of 0.85~0.95; k2 is the particle size influencing factor based on the sand and gravel grading calibration, k2=0.3d 1.5 , d Maximum gravel particle size of the gravel layer, mm; F0 is the design basis resistance, kN; λ is the soil discharge efficiency coefficient of the gravel stratum, rpm·min / mm, λ=Q / 1.4S, where Q is the theoretical displacement of the screw conveyor, m 3 / min; S is the cross-sectional area of ​​the pipe segment, m 2 ; B is the resistance tolerance, kN, which is 5%~10% of F0; f is the permeability coefficient of the sand-gravel stratum; σ0 is the statistical standard deviation of the excavation pressure of the test section of the homogeneous sand-gravel stratum, MPa; k3 is the permeability correction factor, MPa -1 ·s -0.5 .

2. The real-time matching control method for pipe jacking force and formation resistance in gravel formations according to claim 1, characterized in that: The permeability correction factor k3 is calibrated by performing the following operations in the sand and gravel formation test: the jacking speed V is fixed at 20 mm / min; the initial grouting pressure P is j0 Start to increase the grouting pressure step by step and record the standard deviation of the unearthed pressure σ after each increase in grouting pressure s ; According to the formula = Calculate the values ​​for each working condition; take the arithmetic mean of k3 for each working condition as the final calibration value of k3.

3. The real-time matching control method for pipe jacking force and formation resistance in gravel formations according to claim 2, characterized in that: In step S3, if the deviation value of the jacking force measured for three consecutive rings is >15%, the dynamic correction of the particle size influencing factor k2 based on the sand and gravel grading calibration is started: k2'= k2+ , M i -N >0.1s -1 And F c,i -F0>50kN; where F c,i The first is the pressure value of the jacking cylinder of the i-ring pipe jacking machine; M i For the i-th ring T and N s mutation gradient.

4. The real-time matching control method for pipe jacking force and formation resistance in gravel formations according to claim 3, characterized in that: In step S4, when the top pipe is in a curved section and the curvature radius R<500D, P j The relationship between P and the jacking speed V is modified to: j =f×V 0.5 ; Wherein, D is the outer diameter of the jacking pipe segment, m; k4 is the curve segment compensation coefficient, which is 0.02θ; θ is the axis deviation angle between pipe segments during curve jacking, in degrees.

5. The real-time matching control method for pipe jacking force and formation resistance in a gravel formation according to any one of claims 1 to 4, characterized in that: It also includes performing a friction reset operation every 100 rings: Pause jacking and maintain grouting pressure P j 0.8MPa, lasting 5min; The pipe section is slightly retracted by 20mm to release the interface shear stress; When restarting the jacking, the initial speed is reduced to 60% of the speed before the pause and restored in steps of 10% / min.

6. The real-time matching control method for pipe jacking force and formation resistance in gravel formations according to claim 4, characterized in that: The corrected k2, k3 and f' are stored according to the classification of geological radar scanning results. When the geological radar identifies similar stratigraphic features, the historical optimal parameter combination is automatically called for preloading.

7. The real-time matching control method for pipe jacking force and formation resistance in gravel formations according to claim 6, characterized in that: The mechanism for obtaining the historical optimal parameter combination is as follows: Real-time acquisition of geological radar scanning signals to extract characteristic signals of gravel formations: dielectric constant ρ, reflection coefficient φ, and 0.2m scale reflection capacity ratio P 200 ; According to the parameter combination effect evaluation function S=0.5× , calculate the parameter combination with the smallest S as the historical optimal parameter combination; When the radar identifies that the characteristic signals of the gravel formation are the same, the historical optimal parameter combination under the same gravel formation is automatically loaded; The benchmark value of jacking force fluctuation is the standard deviation of the jacking force in the test section.

8. The real-time matching control method for pipe jacking force and formation resistance in gravel formations according to claim 1, characterized in that: When the fluctuation amplitude of the cutterhead speed exceeds ±5% of the set value for 10 consecutive seconds, the target formation resistance prediction value in step S3 is adjusted to F r ':F r '=F r ×8%.

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