A deviation prevention control system for pipe jacking construction of liquefied stratum

Abstract

The application relates to the technical field of liquefied stratum pipe jacking construction, and discloses a deviation prevention and control system for liquefied stratum pipe jacking construction, which comprises a multidimensional acquisition module, a drift analysis module, a stratum analysis unit, a friction analysis module and a deviation management module. The system integrates pipe jacking design, construction monitoring and liquefied stratum detection data through the multidimensional acquisition module, classifies and constructs a data set, the drift analysis module accurately quantifies the drift degree of a laser reference point and generates a drift index, the multidimensional evaluation has high accuracy, the stratum analysis module evaluates the stability of the liquefied stratum within the construction influence range and generates a stability index, the friction analysis module combines the pipe body operation state and the stratum disturbance condition to generate a friction index, the deviation management module determines the credible level of laser-guided pipe jacking propulsion, the risk level of stratum liquefaction potential and the deviation level of the pipe jacking construction process, outputs a judgment result and a response measure, and the deviation prevention and control construction safety is high.

Description

Technical Field

[0001] This invention relates to the field of pipe jacking construction technology in liquefied formations, specifically to a deviation prevention control system for pipe jacking construction in liquefied formations. Background Technology

[0002] Liquefied soil jacking is a special construction method for laying underground pipelines in saturated silt, silt, and fine sand formations prone to liquefaction under earthquakes or dynamic loads. Its core principle is to achieve safe, controllable, and low-disturbance pipeline jacking under extreme conditions of high water pressure, easy liquefaction, and easy collapse. This is achieved through stratum pretreatment, balanced jacking machines, thixotropic mud, and strict dewatering and monitoring. It is widely used in underground engineering projects such as combined sewer overflow channels. Liquefied soil is characterized by a sudden drop in effective stress and loss of shear strength in saturated, loose silt, silt, and fine sand under vibration, resulting in a liquid-like flow of the soil. These formations have uneven mechanical properties, posing extremely high construction risks. Problems such as excavation face instability, sand inrush, ground subsidence or heave, cracking of surrounding buildings, and jacking machine sinking, jamming, axis misalignment, piping, and leakage at pipe joints can easily lead to pipe deviation, disrupting stratum stability and affecting construction safety and project quality. The construction process for pipe jacking in liquefied formations is as follows: First, survey and design are carried out, including detailed investigation of the distribution of liquefied layers, water level, and standard penetration test (SPT) blow count, and liquefaction identification and special design are performed. Dewatering and reinforcement are implemented, using wellpoint dewatering combined with grouting or jet grouting. After the water level stabilizes and the strength meets the standards, jacking begins. Then, the working shaft and receiving shaft are constructed using caisson or reverse construction methods. Water-stop curtains are installed and reinforced on the shaft walls. A slurry balance pipe jacking machine and its supporting slurry, grouting, and monitoring and control systems are installed. A trial jacking of 5-10 meters is conducted, and after optimizing the construction parameters, formal jacking begins. Throughout the process, a continuous and uniform speed is maintained, with frequent and rapid measurements and corrections. Slurry jacketing and pressure control are performed. Finally, receiving and finishing work is completed, including sending the jacking head, connecting pipe sections, sealing the tunnel opening, grouting backfilling, and road surface restoration.

[0003] Currently, traditional anti-deviation control systems used in pipe jacking construction in liquefied formations rely on laser theodolites to emit a reference beam. This system easily overlooks the potential risks of thermal refraction and reference drift in the laser guidance process. During long-distance jacking operations, changes in temperature gradients and air disturbances inside the pipe can cause thermal refraction of the laser beam, resulting in a curved light path and directly leading to the failure of the reference accuracy. In addition, liquefied formations are prone to uneven settlement due to dynamic loads or rainwater immersion, which can cause slight deviations in the laser reference point within the working shaft. Initial deviations are difficult to detect, but as the jacking distance increases, the deviations accumulate and may eventually cause the axis to exceed the allowable range. The subsequent rectification costs are extremely high. This system cannot simultaneously address the issues of uniform drag reduction, real-time deviation correction, anti-deviation control, and formation stability, making it difficult to solve the problems of uneven friction and pipe body tilting in pipe jacking construction in liquefied silty soil formations. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a deviation prevention control system for pipe jacking construction in liquefied formations. This system has advantages such as high accuracy in multi-dimensional assessment and high safety in deviation prevention and control. It solves the problems of reference drift and real-time deviation correction in traditional deviation prevention control systems used in pipe jacking construction in liquefied formations.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a deviation prevention control system for pipe jacking construction in liquefied formations, comprising a multi-dimensional acquisition module, a drift analysis module, a formation analysis unit, a friction analysis module, and a deviation management module; The multi-dimensional acquisition module acquires pipe jacking design data, monitoring data during pipe jacking construction, and detection data of liquefied strata by connecting to a database, laser theodolite, underground radar, pore pressure gauge, and vibration sensor, and classifies them into pipe jacking dataset, construction dataset, and strata dataset. The drift analysis module evaluates the degree of drift of the laser reference point based on the pipe jacking dataset and the construction dataset, and generates a corresponding drift index. ; The formation analysis unit assesses the stability of liquefied formations based on the pipe jacking dataset and the formation dataset, and generates corresponding stability indices. ; The friction analysis module evaluates the friction condition during pipe jacking construction based on the pipe jacking dataset and the construction dataset, and generates a corresponding friction index. ; The deviation management module is configured with a fixed range of drift thresholds. Stable threshold range and friction threshold range Combined with the drift index Stability Index and friction index It determines the reliability level of laser-guided pipe jacking, the risk level of formation liquefaction potential, and the deviation level during pipe jacking construction, and outputs the corresponding judgment results and response measures.

[0006] Preferably, the jacking data set includes the inner radius, axial length, and outer diameter of the jacking pipe.

[0007] Preferably, the construction dataset includes the air temperature at the center of the jacking pipe, the temperature of the jacking pipe wall, the temperature at the starting end of the jacking pipe, the temperature at the reaching end of the jacking pipe, the air pressure inside the jacking pipe, the radial air density at the center of the jacking pipe, the radial air density at the wall of the jacking pipe, the laser propagation path length, the angle between the laser incident direction and the radial gradient, the cumulative vertical settlement of the laser reference point, the maximum allowable vertical settlement of the project, the laser beam spot offset distance, the maximum allowable spot offset distance of the project, the jacking pipe axis deviation, the jacking pipe advancement rate, the cumulative surface settlement, and the cumulative surface horizontal displacement.

[0008] Preferably, the stratum dataset includes the soil midpoint depth, groundwater level depth, measured standard penetration test blow count, thickness, natural unit weight, average pressure of surrounding building foundations, foundation depth of surrounding building foundations, pore water pressure, soil cohesion, soil internal friction angle, pore pressure dissipation monitoring duration, pore water pressure change, and soil midpoint vibration acceleration.

[0009] Preferably, the drift index The calculation process is as follows: S11. Based on the pipe jacking dataset and construction dataset, extract the pipe jacking design data and the monitoring data during the pipe jacking construction process; S12. Calculate the radial temperature gradient inside the jacking pipe. ; S13. Calculate the axial temperature gradient inside the jacking pipe. ; S14. Calculate the radial air refractive index gradient inside the jacking pipe. ; S15. Calculate the axial air refractive index gradient inside the jacking pipe. ; S16. Calculate the radial laser beam deflection angle of the jacking pipe. ; S17. Calculate the axial laser beam deflection angle of the jacking pipe. ; S18. Based on S11-S17, calculate the drift index of the laser reference point using a weighted method. .

[0010] Preferably, the stability index The calculation process is as follows: S21. Based on the pipe jacking dataset and the formation dataset, extract the pipe jacking design data and the detection data of the liquefied formation, and denote the outer diameter of the pipe as... ; S22, in 0~ Within the burial depth range, the soil layers affected by the pipe jacking construction are divided into: Then, calculate the liquefaction index of the formation under natural conditions. ; S23. Calculate the overall shear strength of the soil layer. ; S24. Calculate the pore pressure dissipation rate of the soil layer. ; S25. Calculate the comprehensive vibration disturbance coefficient of the strata. ; S26. Based on S21-S25, calculate the formation stability index using a weighted method. .

[0011] Preferably, the friction index The calculation process is as follows: S31. Based on the pipe jacking dataset and construction dataset, extract the pipe jacking design data and the monitoring data during the pipe jacking construction process; S32. Calculate the dynamic friction coefficient during pipe jacking construction. ; S33. Calculate differential ground settlement during pipe jacking construction. ; S34. Based on S31-S33, calculate the friction index during pipe jacking construction using a weighted method. .

[0012] Preferably, the trust level determination process is as follows: Let the upper limit of the drift threshold range be denoted as The lower limit of the drift threshold interval is denoted as ; During pipe jacking construction, if the drift index of the laser reference point... < This indicates a low degree of laser reference drift, with a reliability level of 1. Response measures include continuing pipe jacking construction as normal, maintaining the existing construction monitoring and inspection frequency, and storing and backing up all data. ≤Drift index of laser reference point ≤ This indicates a moderate degree of laser reference drift, with a confidence level of 2. Response measures include slowing the pipe jacking advance rate, increasing the frequency of construction monitoring and inspection, and activating ventilation devices to regulate the temperature and air pressure inside the pipe. If the laser reference point drift index... > This indicates a high degree of laser reference drift, with a reliability level of 1. Response measures include suspending pipe jacking operations, organizing management personnel to correct the laser reference deviation, and resuming operations once the correction is completed and the drift index stabilizes. < Work will resume after verification and confirmation.

[0013] Preferably, the risk level determination process is as follows: Let the upper limit of the stability threshold range be denoted as The lower limit of the stability threshold interval is denoted as ; During pipe jacking construction, if the stability index of the stratum... > This indicates high formation stability, with a risk level of Level 1. Response measures include continuing the normal pipe jacking construction process, maintaining existing construction monitoring and inspection frequencies, and storing and backing up all data. ≤ Formation stability index ≤ The formation stability is moderate, with a risk level of 2. Response measures include slowing the pipe jacking construction speed, adding pore pressure and vibration monitoring points and increasing monitoring frequency, adjusting the curing agent ratio of the grouting mud, and implementing anti-liquefaction treatment. If the formation stability index... < This indicates low formation stability, with a risk level of 3. Response measures include suspending the pipe jacking construction process, real-time monitoring of formation deformation and liquefaction, and installing high-pressure jet grouting piles for reinforcement. The situation will continue until reinforcement is completed and the stability index is reached. > Work will resume after verification and confirmation.

[0014] Preferably, the deviation level determination process is as follows: Let the upper limit of the friction threshold range be denoted as The lower limit of the friction threshold range is denoted as ; During pipe jacking construction, if the friction index < This indicates a low level of friction disturbance, with a deviation level of 1. Response measures include proceeding with the normal pipe jacking construction process and spraying drag-reducing mud according to current standards. ≤ Friction Index ≤ This indicates a moderate level of friction disturbance, with a deviation level of 2. Response measures include slowing down the pipe jacking construction speed, optimizing and adjusting grouting pressure and flow rate, uniformly increasing the amount of friction-reducing slurry injected, and real-time monitoring of the pipe jacking axis deviation. If the friction index... > This indicates a high degree of frictional disturbance, with a deviation level of 3. Response measures include suspending the pipe jacking construction process, activating the hydraulic cylinders to adjust the pipe jacking axis, and notifying management to revise the grouting plan until the friction index is corrected. < Work will resume after verification and confirmation.

[0015] Compared with the prior art, the present invention provides a deviation prevention control system for pipe jacking construction in liquefied formations, which has the following beneficial effects: 1. This invention integrates multi-source data from pipe jacking design, construction monitoring, and liquefied formation detection through a multi-dimensional acquisition module, classifying and constructing standardized datasets to provide comprehensive and accurate foundational support for subsequent quantitative analysis in each module. The drift analysis module focuses on two core inducing factors: thermal refraction and formation subsidence, accurately quantifying the drift degree of the laser reference point and generating a drift index. It can effectively avoid laser guidance errors and has high accuracy in multi-dimensional evaluation.

[0016] 2. This invention uses a formation analysis module to scientifically and quantitatively evaluate the stability of liquefied formations and construction risks within the construction impact area, generating a stability index. This provides a reliable basis for formation safety assessment, liquefaction prevention treatment, and reinforcement operations. The friction analysis module generates a friction index by combining the pipe's operating status with formation disturbance conditions. This helps improve the scientific and rational nature of construction decisions. The deviation management module determines the reliability level of laser-guided pipe jacking, the risk level of formation liquefaction potential, and the deviation level of the pipe jacking process, and outputs corresponding judgment results and response measures. This enables dynamic control of deviations in pipe jacking construction in liquefied formations throughout the entire process, resulting in a high degree of construction safety due to deviation prevention. Attached Figure Description

[0017] Figure 1 This is a system flowchart of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example Please see Figure 1 Table 1 shows the drift index experimental data, Table 2 shows the stability index experimental data, and Table 3 shows the friction index experimental data. This invention provides a deviation prevention control system for pipe jacking construction in liquefied formations, including a multi-dimensional acquisition module, a drift analysis module, a formation analysis unit, a friction analysis module, and a deviation management module. The multi-dimensional acquisition module acquires pipe jacking design data, monitoring data during pipe jacking construction, and detection data of liquefied strata by connecting to databases, laser theodolites, underground radar, pore pressure gauges, and vibration sensors, and classifies them into pipe jacking datasets, construction datasets, and strata datasets. The jacking data set includes the inner radius, axial length, and outer diameter of the jacking pipe; The construction dataset includes the air temperature at the center of the pipe jacking, the temperature of the pipe jacking wall, the temperature at the starting end of the pipe jacking, the temperature at the reaching end of the pipe jacking, the air pressure inside the pipe jacking, the radial air density at the center of the pipe jacking, the radial air density at the pipe jacking wall, the laser propagation path length, the angle between the laser incident direction and the radial gradient, the cumulative vertical settlement of the laser reference point, the maximum allowable vertical settlement of the project, the laser beam spot offset distance, the maximum allowable spot offset distance of the project, the pipe jacking axis deviation, the pipe jacking advance rate, the cumulative surface settlement, and the cumulative surface horizontal displacement. The stratigraphic dataset includes the soil midpoint depth, groundwater level depth, measured standard penetration test blow count, thickness, natural unit weight, average pressure of surrounding building foundations, foundation depth of surrounding building foundations, pore water pressure, soil cohesion, soil internal friction angle, pore pressure dissipation monitoring duration, pore water pressure change, and vibration acceleration at the soil midpoint. The drift analysis module evaluates the degree of drift of the laser reference point based on the pipe jacking dataset and the construction dataset, and generates the corresponding drift index. ; Drift Index The calculation process is as follows: S11. Based on the pipe jacking dataset and construction dataset, extract the pipe jacking design data and the monitoring data during the pipe jacking construction process; S12. Calculate the radial temperature gradient inside the jacking pipe. Its expression is as follows: In the formula, Indicates the internal radius of the jacking pipe. This indicates the air temperature at the center of the pipe jacking operation. This indicates the temperature of the pipe jacking wall. Specifically, the radial temperature gradient is the rate of temperature change along the radial direction of the pipe (from the center to the wall). The larger the value, the greater the temperature change per unit radial distance, that is, the more drastic the temperature change from the center of the pipe to the wall. This will cause uneven distribution of the air refractive index inside the pipe, which in turn will cause deflection and distortion of the laser beam cross section. S13. Calculate the axial temperature gradient inside the jacking pipe. Its expression is as follows: In the formula, This indicates the axial length of the jacking pipe. This indicates the temperature at the starting point of the pipe jacking process. This indicates the temperature at the end of the jacking pipe; Specifically, in long-distance pipe jacking construction in liquefied formations, the starting end serves as the power and reference point, and the pipe jacking proceeds gradually along the horizontal axis towards the destination end. The starting end is the rear end (fixed end) of the jacking direction, where core equipment such as laser theodolites and main jacking cylinders are located. It is the source of laser guidance reference and jacking thrust. The destination end is the front end (target end) of the jacking direction, where the pipe jacking machine finally penetrates and receives the pipe. The axial temperature gradient is the rate of temperature change along the axial length of the pipe. The larger this value, the greater the temperature change per unit axial distance, meaning the more drastic the temperature change along the length of the pipe. This is the main factor causing long-distance cumulative deflection of the laser beam, and the cumulative effect will significantly amplify the risk of pipe jacking axis deviation. S14. Calculate the radial air refractive index gradient inside the jacking pipe. Its expression is as follows: In the formula, This indicates the air pressure inside the jacking pipe. Indicates the molar mass of air. Represents the universal gas constant. The unit conversion constant for converting Celsius temperature to Kelvin temperature. This indicates the radial air density at the center of the jacking pipe. This indicates the radial air density of the jacking pipe wall; In the formula, The Gladstone-Dale constant for air is taken as follows under standard operating conditions. , Indicates the radial air refractive index at the center of the jacking pipe. Indicates the radial air refractive index of the jacking pipe wall; Specifically, based on the principle that temperature gradient induces refractive index gradient, which in turn leads to laser beam deflection, a quantitative method for laser beam deflection angle and the risk of jacking pipe axis deviation can be directly derived, while providing a theoretical basis for the formulation of deviation control measures. S15. Calculate the axial air refractive index gradient inside the jacking pipe. Its expression is as follows: In the formula, This indicates the axial air density at the starting end of the pipe jacking process. This indicates the axial air density at the end of the jacking pipe; In the formula, This indicates the axial air refractive index at the starting end of the pipe jacking process. Indicates the axial air refractive index at the end of the jacking pipe; Specifically, the radial air refractive index gradient The localized and transient nature of this phenomenon alters the laser beam propagation path, causing beam distortion or center shift. This can easily lead the receiver to misjudge that the pipe jacking machine has deviated from its axis, when in reality it is due to the bending of the beam's own propagation trajectory. In complex conditions such as liquefied formations, the axial air refractive index gradient... The long-distance cumulative risk is more insidious. This gradient is global and cumulative, mainly affecting the phase and line-of-sight of laser propagation. During long-distance transmission, its slow refractive index change will cause the laser beam to be deflected at a small angle when it reaches the receiving end. The cumulative effect is ultimately manifested as a systematic overall shift in the position of the target point. S16. Calculate the radial laser beam deflection angle of the jacking pipe. Its expression is as follows: In the formula, This represents the average refractive index of the air inside the pipe. Indicates the length of the laser propagation path. This represents the angle between the laser incident direction and the radial gradient; S17. Calculate the axial laser beam deflection angle of the jacking pipe. Its expression is as follows: Specifically, radial laser beam deflection angle The axial laser beam deflection angle reflects the attitude distortion of the laser beam within the pipe cross-section. This reflects the longitudinal expansion and contraction of the laser beam within the pipeline; when the construction distance is long, the axial laser beam deflection angle... The resulting error amplifies linearly with distance, which is the core reason for the implicit overall drift of the laser reference. S18. Based on S11-S17, calculate the drift index of the laser reference point using a weighted method. Its expression is as follows: For the radial air refractive index gradient inside the jacking pipe Axial air refractive index gradient Radial laser beam deflection angle Axial laser beam deflection angle Vertical cumulative settlement of laser reference point With the maximum allowable vertical settlement of the project The ratio of the laser beam's spot offset distance Maximum spot offset distance allowed by the project The ratio is dimensionless, so that all parameters are mapped to a uniform order of magnitude; Specifically, dimensionless processing ensures the comparability of parameters with different attributes and units, thereby guaranteeing the scientific validity and rationality of the weight calculation results. The standardized dimensionless processing procedure is as follows: First, historical parameters from multiple time points within a fixed time period are collected to construct a complete raw data sequence. Then, the mean and standard deviation of the corresponding parameters are calculated based on this sequence. Finally, the raw data values ​​are converted into dimensionless values ​​by calculating "(raw data value at any time point - mean) ÷ standard deviation". After this processing, the mean of all indicators is 0 and the standard deviation is 1, which ensures that all indicators are on the same order of magnitude, laying the foundation for subsequent weighted calculations. In the formula, , , , , and All are dimensionless values ​​after normalization. , , , , and All are weights, and satisfy the following conditions: ; Specifically, liquefied formations are prone to uneven settlement under dynamic loads or rainwater immersion, leading to slight shifts in the laser reference point within the working well. Based on the two core causes of drift—laser beam shift due to thermal refraction and reference point shift due to formation settlement—multi-dimensional influencing factors are incorporated and assigned differentiated weights, resulting in a drift index. This provides precise quantitative support for the formulation of targeted response and prevention strategies for subsequent pipe jacking axis deviation; The following are the experimental data for the drift index, as shown in Table 1: Table 1: Experimental Data for the Drift Index In Table 1, the drift index experimental data shows that pipe A was selected as the experimental target. After dimensionless processing, the radial air refractive index gradient inside the jacking pipe The axial air refractive index gradient is 0.25. The radial laser beam deflection angle is 0.18. The axial laser beam deflection angle is 0.32. The ratio of the cumulative vertical settlement of the laser reference point to the maximum allowable vertical settlement of the project is 0.08. The ratio of the laser beam spot offset distance to the maximum allowable spot offset distance in engineering is 0.015. It is 0.02; Weights set to , , , , , ; The deviation management module is set with a fixed range of drift thresholds. This system is used to accurately determine the degree of drift of the laser reference point during pipe jacking construction, providing a quantitative reference for adjusting construction procedures and formulating emergency response measures. The rationality of the range directly affects the accuracy of drift level assessment and the timeliness of construction intervention. An excessively narrow drift threshold range... Overly strict drift classification can lead to misjudging moderate drift as high drift, increasing the risk of unnecessary construction stoppages and excessive correction operations, while reducing construction efficiency and increasing costs. Conversely, overly strict drift classification can blur the drift level definition, making it impossible to distinguish between high and moderate drift, or moderate and low drift, delaying targeted emergency response to high drift and creating potential quality and safety hazards such as pipe jacking axis deviation and pipe section misalignment. Therefore, the optimal range of this threshold interval needs to be determined through the calibration experiments of the following system: Drift Threshold Interval The calibration method is as follows: Construction samples with varying degrees of laser reference point drift were screened using a pipe jacking construction engineering database, covering various working conditions including low, medium, and high laser reference point drift. Construction monitoring data (such as laser reference point offset, pipe jacking rate, and pipe internal temperature and pressure), process adjustment records, and construction quality acceptance results (such as axis deviation, pipe section splicing quality, and project rectification status) were extracted from the sample projects. Different candidate threshold ranges were set. In each calibration experiment, the drift level of the sample projects was classified based on the candidate threshold range, and the matching degree between the classification results and the actual construction gold standard judgment results was recorded. Combined with dynamic construction process data, the laser reference point drift index was simulated under different emergency responses and construction adjustment rhythms. The changing trend was analyzed, and the upper and lower limits of the candidate threshold interval were adjusted. Multiple verification experiments were conducted to record the impact of the threshold interval setting on the evaluation of construction treatment effects. For each candidate threshold interval, the collected sample data and dynamic simulation results were used as inputs to count the number of times low-level drift was misjudged as high-level drift due to improper interval setting (counted as over-evaluation), the number of times high-level drift was misjudged as low-level drift (counted as under-evaluation), and the degree of fit between the drift level classification results and the construction treatment effects (such as the success rate of correction, the pass rate of construction quality, and the completion rate of the project). Finally, the interval range that minimizes both the over-evaluation rate and the under-evaluation rate and has the highest degree of fit with the construction treatment effect was selected as the drift threshold interval. The preferred range; In Table 1, the drift index experimental data shows the drift threshold range. The preferred range is 0.1 to 0.5. Based on the assessment, during the construction of pipe jacking A, the drift index of the laser reference point... A value between 0.1 and 0.5 indicates a moderate degree of laser reference drift, with a confidence level of 2. Response measures include slowing down the advance rate of pipe jacking A, increasing the frequency of construction monitoring and inspection, and activating ventilation devices to regulate the temperature and air pressure inside the pipe. The formation analysis unit assesses the stability of liquefied formations based on the pipe jacking dataset and the formation dataset, and generates corresponding stability indices. ; Stability Index The calculation process is as follows: S21. Based on the pipe jacking dataset and the formation dataset, extract the pipe jacking design data and the detection data of the liquefied formation, and denote the outer diameter of the pipe as... ; S22, in 0~ Within the burial depth range, the soil layers affected by the pipe jacking construction are divided into: Then, calculate the liquefaction index of the formation under natural conditions. This is used to reflect the liquefaction potential of a formation under natural conditions, and its expression is as follows: In the formula, This represents the correction factor for clay content. Indicates the first The midpoint of the soil layer is buried at a certain depth. , Indicates the depth of the groundwater level. Indicates the first Critical penetration blow count for soil layers; In the formula, Indicates the first The measured standard penetration test blow count of the soil layer. Indicates the first The thickness of the soil layer, Indicates the first The weight function values ​​of the soil layers; S23. Calculate the overall shear strength of the soil layer. This is used to characterize the shear stability of the formation under the disturbance conditions of pipe jacking construction, and its expression is as follows: In the formula, This indicates the natural unit weight of the soil layer. Indicates the first The soil self-weight stress of the soil layer; In the formula, This indicates the average pressure on the foundations of surrounding buildings. This indicates the foundation depth of the surrounding buildings. Indicates the first The total stress of the soil layer. Indicates the first The pore water pressure of the soil layer Indicates the first Effective stress in the soil layer; In the formula, Indicates the first The soil cohesion of the soil layer, Indicates the first The internal friction angle of the soil layer. Indicates the first Shear strength of the soil layer; S24. Calculate the pore pressure dissipation rate of the soil layer. This denoted is used to reflect the ability of liquefied soil to return to a stable state, and its expression is as follows: In the formula, Indicates the monitoring duration of pore pressure dissipation. This represents the change in pore water pressure during the monitoring period, expressed as an absolute value. S25. Calculate the comprehensive vibration disturbance coefficient of the strata. Its expression is as follows: In the formula, Indicates the first The vibration acceleration at the midpoint of the soil layer, This represents the acceleration due to gravity, with a value of 9.8 m / s². Indicates the first Vibration disturbance coefficient of the soil layer; Take 0~ Within the burial depth range, the vibration interference coefficient of all soil layers The maximum value is used as the comprehensive vibration disturbance coefficient of the strata. ; S26. Based on S21-S25, calculate the formation stability index using a weighted method. Its expression is as follows: Liquefaction index of formations in their natural state Comprehensive shear strength of soil layers The reciprocal of the soil pore pressure dissipation rate The reciprocal of the combined ground vibration disturbance coefficient Dimensionless processing is performed to map all parameters to a uniform order of magnitude; Specifically, dimensionless processing ensures the comparability of parameters with different attributes and units, thereby guaranteeing the scientific validity and rationality of the weight calculation results. The standardized dimensionless processing procedure is as follows: First, historical parameters from multiple time points within a fixed time period are collected to construct a complete raw data sequence. Then, the mean and standard deviation of the corresponding parameters are calculated based on this sequence. Finally, the raw data values ​​are converted into dimensionless values ​​by calculating "(raw data value at any time point - mean) ÷ standard deviation". After this processing, the mean of all indicators is 0 and the standard deviation is 1, which ensures that all indicators are on the same order of magnitude, laying the foundation for subsequent weighted calculations. In the formula, , , and All are dimensionless values ​​after normalization. , , and All are constants and satisfy the following conditions: ; Specifically, by quantifying the engineering characteristics of liquefied strata within the impact range of pipe jacking construction from multiple dimensions, a stability index is obtained through weighted integration. This enables a scientific and objective quantitative evaluation of formation stability and construction risks, providing accurate numerical reference for the assessment of formation safety in pipe jacking construction. The higher the value, the stronger the formation stability and the lower the construction risk; the lower the value, the worse the formation stability and the higher the construction risk. The following is the experimental data for the stability index, as shown in Table 2: Table 2: Experimental Data for the Stability Index In Table 2, the stability index experimental data shows that pipe jacking construction project B was selected as the experimental target. liquefaction index of the formation under natural conditions after dimensionless treatment The value is 0.32, which is the reciprocal of the comprehensive shear strength of the soil layer. The value is 0.28, which is the reciprocal of the soil pore pressure dissipation rate. The comprehensive ground vibration disturbance coefficient is 0.25. It is 0.15; Weights set to , , , ; The deviation management module is set with a fixed range of stable thresholds. This method is used to accurately determine the stability of the strata during pipe jacking construction, providing a quantitative reference for adjusting the construction process and formulating risk control measures. The rationality of the range directly affects the accuracy of the strata stability risk level assessment and the timeliness of construction risk intervention. An excessively narrow stability threshold range... Overly stringent risk classification can lead to misclassifying moderately stable formations as low-stability ones, increasing the risk of unnecessary construction halts and over-reinforcement, while also reducing construction efficiency and increasing costs. Conversely, overly lenient risk classification can blur the lines between low-stability and moderately stable formations, and between moderately stable and highly stable formations, delaying targeted risk management in low-stability formations and creating potential engineering quality and construction safety hazards such as formation liquefaction, piping, and axis misalignment. Therefore, the optimal range for this threshold interval needs to be determined through calibration experiments of the following systems: Stability Threshold Interval The calibration method is as follows: Construction samples with varying degrees of ground stability were screened using a pipe jacking construction engineering database, covering various working conditions including high, medium, and low ground stability. Ground monitoring data (such as ground deformation, pore pressure, and vibration frequency), construction parameter adjustment records, and construction quality and safety acceptance results (such as ground liquefaction, pipe section offset, and engineering rectification) were extracted from the sample projects. Different candidate threshold ranges were set. In each calibration experiment, the ground stability risk level of the sample projects was classified based on the candidate threshold range. The matching degree between the classification results and the gold standard judgment results from actual construction measurements was recorded. Combined with dynamic construction process data, the ground stability index was simulated under different risk control and construction adjustment rhythms. The changing trend was analyzed, and the upper and lower limits of the candidate threshold intervals were adjusted. Multiple verification experiments were conducted to record the impact of threshold interval settings on the evaluation of construction risk management effectiveness. For each candidate threshold interval, the collected sample data and dynamic simulation results were used as inputs to count the number of times low-level risks were misjudged as high-level risks due to improper interval settings (counted as over-assessment), the number of times high-level risks were misjudged as low-level risks (counted as under-assessment), and the degree of fit between the risk level classification results and the construction risk management effectiveness (such as the success rate of ground reinforcement, the pass rate of construction quality, and the incidence rate of safety accidents). Finally, the interval range that minimizes both the over-assessment rate and the under-assessment rate and has the highest degree of fit with the construction risk management effectiveness was selected as the stable threshold interval. The preferred range; In Table 2, the stability threshold range is shown in the experimental data of the stability index. The preferred range is 0.2 to 0.5. Based on the assessment, during the B stage of the pipe jacking construction project, the stability index of the formation is... A value between 0.2 and 0.5 indicates moderate formation stability, with a risk level of 2. Response measures include slowing down the pipe jacking construction speed, adding pore pressure and vibration monitoring points and increasing the monitoring frequency, adjusting the curing agent ratio of the grouting mud, and carrying out anti-liquefaction treatment. The friction analysis module evaluates the friction conditions during pipe jacking construction based on the pipe jacking dataset and the construction dataset, and generates the corresponding friction index. ; Friction Index The calculation process is as follows: S31. Based on the pipe jacking dataset and construction dataset, extract the pipe jacking design data and the monitoring data during the pipe jacking construction process; S32. Calculate the dynamic friction coefficient during pipe jacking construction. Its expression is as follows: In the formula, This represents the correction factor corresponding to the deviation of the jacking pipe axis. This represents the correction factor corresponding to the pipe jacking advance rate. This indicates the axial length of the jacking pipe. Indicates the deviation of the jacking pipe axis. Indicates the pipe jacking advance rate; S33. Calculate differential ground settlement during pipe jacking construction. Its expression is as follows: In the formula, This represents the correction factor corresponding to the cumulative surface subsidence. This represents the correction factor corresponding to the cumulative horizontal displacement of the Earth's surface. It represents the cumulative surface settlement, used to reflect the vertical disturbance of the strata during construction. It represents the cumulative horizontal displacement of the ground surface, used to reflect the horizontal disturbance of the strata during the construction process; S34. Based on S31-S33, calculate the friction index during pipe jacking construction using a weighted method. Its expression is as follows: In the formula, and All are constants and satisfy the following conditions: ; Specifically, by comprehensively considering the pipe's operating status and ground disturbance during pipe jacking construction, the friction index can fully and accurately reflect the actual friction conditions during construction. The larger the value, the higher the degree of friction disturbance. This provides a scientific and systematic calculation basis for friction analysis and construction control in pipe jacking construction, and helps to improve the rationality of construction decisions. The following are the experimental data for the friction index, as shown in Table 3: Table 3: Experimental Data for Friction Index In Table 3, the friction index experimental data were used to select pipe jacking construction project C as the experimental target. Weights set to , ; The deviation management module is set with a fixed range of friction threshold intervals. The friction threshold is a core quantitative benchmark used to accurately assess the degree of external interference affecting pipeline friction during pipe jacking construction. It is directly related to construction efficiency, friction reduction costs, and the accuracy of pipe jacking axis control. The scientific nature of the range is crucial. If the range is too narrow, moderate interference may be misjudged as high interference, leading to excessive work stoppages and corrections, causing delays and resource waste. If the range is too wide, it is difficult to distinguish between high and moderate interference conditions, making it impossible to provide timely warnings and handle high friction risks. This can easily lead to serious engineering accidents such as pipe jacking blockage, excessive axis deviation, and excessive pipeline wear. Therefore, a systematic calibration test is needed to determine the friction threshold range. The optimal range is determined, and the specific calibration process is as follows: Relying on the big data platform for pipe jacking construction, comprehensive friction monitoring samples were collected under different geological conditions and propulsion parameters, covering three typical working conditions: low-interference, medium-interference, and high-interference friction. The core monitoring data corresponding to the samples were systematically sorted out, including the friction index. The data includes jacking force, grouting pressure, mud viscosity, and jacking speed. Simultaneously, it records process adjustment records, on-site handling plans, and final construction results (such as axis deviation, pipe section wear, and jacking operation time). Based on this data, multiple candidate ranges for friction threshold intervals are set. Each candidate interval is used to classify the deviation level of the sample working conditions. The classification results are compared with the "real interference level" obtained through manual inspection and high-precision measurement at the engineering site. The degree of fit between the two is calculated. Combined with construction dynamic simulation technology, the friction index is extrapolated under different candidate threshold intervals. As the dynamic changes in the construction operation are observed, the effects of different response measures (such as adjusting the grouting process, initiating hydraulic correction, and suspending construction) on the friction state are simulated. For each candidate threshold range, multiple rounds of verification tests are conducted to quantitatively evaluate the impact of threshold settings on construction risk control. The misjudgment rate is statistically analyzed, including the number of times low-interference scenarios are misjudged as high-interference (over-evaluation) and the number of times high-interference scenarios are misjudged as low-interference (under-evaluation). Simultaneously, the correlation between threshold settings and construction safety factor, resource consumption rate, and project completion rate is analyzed. Finally, considering the accuracy of evaluation, construction safety, and economy, the range that simultaneously minimizes the over-evaluation and under-evaluation rates and achieves the optimal construction risk management effect is selected as the friction threshold range. The final calibration result; In Table 3, the friction index experimental data shows the friction threshold range. The preferred range is 0.3 to 0.6. Based on the assessment, during the C stage of the pipe jacking construction project, the friction index... A value between 0.3 and 0.6 indicates a moderate level of friction disturbance, with a deviation level of 2. Response measures include slowing down the pipe jacking construction speed, optimizing and adjusting grouting pressure and flow rate, uniformly increasing the amount of friction-reducing slurry injected, and real-time monitoring of the pipe jacking axis deviation. The deviation management module is set with a fixed range of drift thresholds. Stable threshold range and friction threshold range Combined with the drift index Stability Index and friction index The system determines the reliability level of laser-guided pipe jacking, the risk level of formation liquefaction potential, and the deviation level during pipe jacking construction, and outputs the corresponding judgment results and response measures. The trust level determination process is as follows: Let the upper limit of the drift threshold range be denoted as The lower limit of the drift threshold interval is denoted as ; During pipe jacking construction, if the drift index of the laser reference point... < This indicates a low degree of laser reference drift, with a reliability level of 1. Response measures include continuing pipe jacking construction as normal, maintaining the existing construction monitoring and inspection frequency, and storing and backing up all data. ≤Drift index of laser reference point ≤ This indicates a moderate degree of laser reference drift, with a confidence level of 2. Response measures include slowing the pipe jacking advance rate, increasing the frequency of construction monitoring and inspection, and activating ventilation devices to regulate the temperature and air pressure inside the pipe. If the laser reference point drift index... > This indicates a high degree of laser reference drift, with a reliability level of 1. Response measures include suspending pipe jacking operations, organizing management personnel to correct the laser reference deviation, and resuming operations once the correction is completed and the drift index stabilizes. < Work will resume after verification and confirmation. The risk level assessment process is as follows: Let the upper limit of the stability threshold range be denoted as The lower limit of the stability threshold interval is denoted as ; During pipe jacking construction, if the stability index of the stratum... > This indicates high formation stability, with a risk level of Level 1. Response measures include continuing the normal pipe jacking construction process, maintaining existing construction monitoring and inspection frequencies, and storing and backing up all data. ≤ Formation stability index ≤ The formation stability is moderate, with a risk level of 2. Response measures include slowing the pipe jacking construction speed, adding pore pressure and vibration monitoring points and increasing monitoring frequency, adjusting the curing agent ratio of the grouting mud, and implementing anti-liquefaction treatment. If the formation stability index... < This indicates low formation stability, with a risk level of 3. Response measures include suspending the pipe jacking construction process, real-time monitoring of formation deformation and liquefaction, and installing high-pressure jet grouting piles for reinforcement. The situation will continue until reinforcement is completed and the stability index is reached. > Work will resume after verification and confirmation. The deviation level determination process is as follows: Let the upper limit of the friction threshold range be denoted as The lower limit of the friction threshold range is denoted as ; During pipe jacking construction, if the friction index < This indicates a low level of friction disturbance, with a deviation level of 1. Response measures include proceeding with the normal pipe jacking construction process and spraying drag-reducing mud according to current standards. ≤ Friction Index ≤ This indicates a moderate level of friction disturbance, with a deviation level of 2. Response measures include slowing down the pipe jacking construction speed, optimizing and adjusting grouting pressure and flow rate, uniformly increasing the amount of friction-reducing slurry injected, and real-time monitoring of the pipe jacking axis deviation. If the friction index... > This indicates a high degree of frictional disturbance, with a deviation level of 3. Response measures include suspending the pipe jacking construction process, activating the hydraulic cylinders to adjust the pipe jacking axis, and notifying management to revise the grouting plan until the friction index is corrected. < Work will resume after verification and confirmation.

[0020] In this embodiment, a multi-source data acquisition module integrates data from pipe jacking design, construction monitoring, and liquefied formation detection, and classifies and constructs a standardized dataset to provide comprehensive and accurate foundational support for subsequent quantitative analysis in each module. The drift analysis module focuses on two core inducing factors: thermal refraction and formation subsidence, accurately quantifies the drift degree of the laser reference point, and generates a drift index. It can effectively avoid laser guidance errors. The formation analysis module scientifically and quantitatively evaluates the stability of liquefied formations and construction risks within the construction influence range, and generates a stability index. This provides a reliable basis for formation safety assessment, liquefaction prevention treatment, and reinforcement operations. The friction analysis module combines the pipe's operating status with formation disturbance conditions to generate a friction index. This helps improve the scientific and rational nature of construction decisions. The deviation management module determines the reliability level of laser-guided pipe jacking, the risk level of formation liquefaction potential, and the deviation level of the pipe jacking process, and outputs corresponding judgment conclusions and response measures. This enables dynamic control of deviations in pipe jacking construction in liquefied formations throughout the entire process, differentiated construction adjustments, and emergency response, effectively preventing the expansion of deviations and ensuring the safe and efficient progress of the construction project.

[0021] The threshold is set to facilitate comparison. The size of the threshold depends on the amount of sample data and the number of bases set by those skilled in the art for each set of sample data; as long as it does not affect the ratio between the parameter and the quantized value, it is acceptable.

[0022] The above formulas are all derived from software simulation using a large amount of data and are selected to be close to the actual values. The coefficients in the formulas are set by those skilled in the art according to the actual situation. The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the protection scope of the present invention.

Claims

1. A deviation prevention control system for pipe jacking construction in liquefied formations, characterized in that: It includes a multi-dimensional acquisition module, a drift analysis module, a formation analysis unit, a friction analysis module, and a deviation management module; The multi-dimensional acquisition module acquires pipe jacking design data, monitoring data during pipe jacking construction, and detection data of liquefied strata by connecting to a database, laser theodolite, underground radar, pore pressure gauge, and vibration sensor, and classifies them into pipe jacking dataset, construction dataset, and strata dataset. The drift analysis module evaluates the degree of drift of the laser reference point based on the pipe jacking dataset and the construction dataset, and generates a corresponding drift index. ; The formation analysis unit assesses the stability of liquefied formations based on the pipe jacking dataset and the formation dataset, and generates corresponding stability indices. ; The friction analysis module evaluates the friction condition during pipe jacking construction based on the pipe jacking dataset and the construction dataset, and generates a corresponding friction index. ; The deviation management module is configured with a fixed range of drift thresholds. Stable threshold range and friction threshold range Combined with the drift index Stability Index and friction index It determines the reliability level of laser-guided pipe jacking, the risk level of formation liquefaction potential, and the deviation level during pipe jacking construction, and outputs the corresponding judgment results and response measures.

2. The anti-deviation control system for pipe jacking construction in liquefied formations according to claim 1, characterized in that: The jacking data set includes the inner radius, axial length, and outer diameter of the jacking pipe.

3. The anti-deviation control system for pipe jacking construction in liquefied formations according to claim 2, characterized in that: The construction dataset includes the air temperature at the center of the jacking pipe, the temperature of the jacking pipe wall, the temperature at the starting end of the jacking pipe, the temperature at the reaching end of the jacking pipe, the air pressure inside the jacking pipe, the radial air density at the center of the jacking pipe, the radial air density at the wall of the jacking pipe, the length of the laser propagation path, the angle between the laser incident direction and the radial gradient, the cumulative vertical settlement of the laser reference point, the maximum allowable vertical settlement of the project, the laser beam spot offset distance, the maximum allowable spot offset distance of the project, the deviation of the jacking pipe axis, the jacking pipe advancement rate, the cumulative surface settlement, and the cumulative surface horizontal displacement.

4. A deviation prevention control system for pipe jacking construction in liquefied formations according to claim 3, characterized in that: The stratigraphic dataset includes the soil midpoint depth, groundwater level depth, measured standard penetration test blow count, thickness, natural unit weight, average pressure of surrounding building foundations, foundation depth of surrounding building foundations, pore water pressure, soil cohesion, soil internal friction angle, pore pressure dissipation monitoring duration, pore water pressure change, and soil midpoint vibration acceleration.

5. A deviation prevention control system for pipe jacking construction in liquefied formations according to claim 4, characterized in that: The drift index The calculation process is as follows: S11. Based on the pipe jacking dataset and construction dataset, extract the pipe jacking design data and the monitoring data during the pipe jacking construction process; S12. Calculate the radial temperature gradient inside the jacking pipe. ; S13. Calculate the axial temperature gradient inside the jacking pipe. ; S14. Calculate the radial air refractive index gradient inside the jacking pipe. ; S15. Calculate the axial air refractive index gradient inside the jacking pipe. ; S16. Calculate the radial laser beam deflection angle of the jacking pipe. ; S17. Calculate the axial laser beam deflection angle of the jacking pipe. ; S18. Based on S11-S17, calculate the drift index of the laser reference point using a weighted method. .

6. A deviation prevention control system for pipe jacking construction in liquefied formations according to claim 5, characterized in that: The stability index The calculation process is as follows: S21. Based on the pipe jacking dataset and the formation dataset, extract the pipe jacking design data and the detection data of the liquefied formation, and denote the outer diameter of the pipe as... ; S22, in 0~ Within the burial depth range, the soil layers affected by the pipe jacking construction are divided into: Then, calculate the liquefaction index of the formation under natural conditions. ; S23. Calculate the overall shear strength of the soil layer. ; S24. Calculate the pore pressure dissipation rate of the soil layer. ; S25. Calculate the comprehensive vibration disturbance coefficient of the strata. ; S26. Based on S21-S25, calculate the formation stability index using a weighted method. .

7. A deviation prevention control system for pipe jacking construction in liquefied formations according to claim 6, characterized in that: The friction index The calculation process is as follows: S31. Based on the pipe jacking dataset and construction dataset, extract the pipe jacking design data and the monitoring data during the pipe jacking construction process; S32. Calculate the dynamic friction coefficient during pipe jacking construction. ; S33. Calculate differential ground settlement during pipe jacking construction. ; S34. Based on S31-S33, calculate the friction index during pipe jacking construction using a weighted method. .

8. A deviation prevention control system for pipe jacking construction in liquefied formations according to claim 7, characterized in that: The trust level determination process is as follows: Let the upper limit of the drift threshold range be denoted as The lower limit of the drift threshold interval is denoted as ; During pipe jacking construction, if the drift index of the laser reference point... < This indicates a low degree of laser reference drift, with a reliability level of 1. Response measures include continuing pipe jacking construction as normal, maintaining the existing construction monitoring and inspection frequency, and storing and backing up all data. ≤Drift index of laser reference point ≤ This indicates a moderate degree of laser reference drift, with a confidence level of 2. Response measures include slowing the pipe jacking advance rate, increasing the frequency of construction monitoring and inspection, and activating ventilation devices to regulate the temperature and air pressure inside the pipe. If the laser reference point drift index... > This indicates a high degree of laser reference drift, with a reliability level of 1. Response measures include suspending pipe jacking operations, organizing management personnel to correct the laser reference deviation, and resuming operations once the correction is completed and the drift index stabilizes. < Work will resume after verification and confirmation.

9. A deviation prevention control system for pipe jacking construction in liquefied formations according to claim 8, characterized in that: The risk level assessment process is as follows: Let the upper limit of the stability threshold range be denoted as The lower limit of the stability threshold interval is denoted as ; During pipe jacking construction, if the stability index of the stratum... > This indicates high formation stability, with a risk level of Level 1. Response measures include continuing the normal pipe jacking construction process, maintaining existing construction monitoring and inspection frequencies, and storing and backing up all data. ≤ Formation stability index ≤ The formation stability is moderate, with a risk level of 2. Response measures include slowing the pipe jacking construction speed, adding pore pressure and vibration monitoring points and increasing monitoring frequency, adjusting the curing agent ratio of the grouting mud, and implementing anti-liquefaction treatment. If the formation stability index... < This indicates low formation stability, with a risk level of 3. Response measures include suspending the pipe jacking construction process, real-time monitoring of formation deformation and liquefaction, and installing high-pressure jet grouting piles for reinforcement. The situation will continue until reinforcement is completed and the stability index is reached. > Work will resume after verification and confirmation.

10. A deviation prevention control system for pipe jacking construction in liquefied formations according to claim 9, characterized in that: The deviation level determination process is as follows: Let the upper limit of the friction threshold range be denoted as The lower limit of the friction threshold range is denoted as ; During pipe jacking construction, if the friction index < This indicates a low level of friction disturbance, with a deviation level of 1. Response measures include proceeding with the normal pipe jacking construction process and spraying drag-reducing mud according to current standards. ≤ Friction Index ≤ This indicates a moderate level of friction disturbance, with a deviation level of 2. Response measures include slowing down the pipe jacking construction speed, optimizing and adjusting grouting pressure and flow rate, uniformly increasing the amount of friction-reducing slurry injected, and real-time monitoring of the pipe jacking axis deviation. If the friction index... > This indicates a high degree of frictional disturbance, with a deviation level of 3. Response measures include suspending the pipe jacking construction process, activating the hydraulic cylinders to adjust the pipe jacking axis, and notifying management to revise the grouting plan until the friction index is corrected. < Work will resume after verification and confirmation.

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