Shield tunneling parameter dynamic adjustment system based on surface settlement tank shape

Abstract

The present application relates to the technical field of automatic control of shield tunnel construction, and specifically discloses a shield tunneling parameter dynamic adjustment system based on the form of surface settlement tank, which comprises the following steps: determining the critical value of earth pressure failure through the correlation analysis of the number of passes of historical pressure increase events and the settlement improvement rate; dividing the face influence period and the shield tail release period based on the critical value of earth pressure failure, and determining the risk of earth pressure control failure from three aspects of effectiveness, harmfulness and pressure regulation frequency; switching the risk section to a fine collection mode, fitting the cross section of the settlement tank by using the Peck formula and extracting characteristic parameters; dividing the section into different control sections according to the difference in the number of rings and dynamically assigning weight coefficients; generating the earth pressure adjustment reference value and the grouting amount adjustment reference value through weighted fusion, and deciding the smooth transition strategy according to the thrust disturbance degree in the weight switching interval, so as to realize the accurate and smooth adjustment of shield tunneling parameters and effectively control the surface settlement.

Description

Technical Field

[0001] This invention relates to the field of automated control technology for shield tunnel construction, specifically to a dynamic adjustment system for shield tunneling parameters based on the morphology of surface settlement troughs. Background Technology

[0002] Shield tunneling, with its advantages of high construction speed and minimal impact on the surrounding environment, has become the mainstream method for urban underground tunnel construction. However, shield tunneling inevitably disturbs the surrounding strata, leading to surface settlement. When settlement exceeds the allowable range, it may endanger the safety of surface buildings, underground pipelines, and the surrounding environment. The mechanism of surface settlement caused by shield tunneling is complex, involving the combined effects of multiple factors such as face earth pressure support, shield friction, and tail grouting. The contribution weight of each factor to surface settlement varies significantly at different construction stages. Therefore, effectively controlling surface settlement during shield tunneling is one of the core issues in shield construction technology.

[0003] Existing automatic shield tunneling control systems suffer from the following core problems in actual operation: When the shield machine has passed a certain monitoring section and traveled a certain distance, the surface settlement trough morphology of that section is mainly determined by the grouting density of the tail section. Face earth pressure adjustment has almost no effect on the settled strata at that section; in fact, it may increase additional disturbance to the strata ahead due to sudden thrust changes. In this specific scenario, many automation systems fail to set phased control weights according to the shield machine's spatial position, leading to the erroneous activation of earth pressure adjustment commands based on settlement monitoring data at the tail section during the tail grouting stage. This causes unexpected sudden changes in the total thrust of the propulsion cylinders, resulting in excessive deviations in the shield machine's horizontal or vertical attitude, and in severe cases, even causing the shield machine to deviate from its design axis.

[0004] To address this, the present invention provides a dynamic adjustment system for shield tunneling parameters based on the morphology of surface settlement troughs. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies and solve at least one of the technical problems mentioned in the background art, this invention provides a dynamic adjustment system for shield tunneling parameters based on the morphology of surface settlement troughs. Addressing the problem of sudden changes in propulsion resistance caused by incorrect activation of earth pressure adjustment during the tail grouting stage, which in turn leads to loss of control of the shield machine's attitude, this invention solves the problem of spatial mismatch-type earth pressure miscontrol caused by existing automated systems failing to distinguish between the face influence period and the tail detachment period.

[0006] The objective of this invention can be achieved through the following technical solution: a dynamic adjustment system for shield tunneling parameters based on the morphology of surface settlement troughs, comprising the following modules: Critical value determination module: Obtain historical pressure increase events and corresponding cross sections, and determine the critical value of earth pressure failure through correlation analysis by link number and settlement improvement rate; Risk assessment module: Based on the critical value of earth pressure failure, the monitoring section is divided into the face influence period and the shield tail release period. Based on the settlement improvement rate and thrust change rate of the pressure rise event during the shield tail release period, combined with the comparative analysis of the pressure adjustment frequency during the face influence period and the shield tail release period, it is determined whether there is a risk of earth pressure miscontrol. Feature extraction module: If present, perform real-time fitting of the surface settlement trough cross sections of each monitoring section to extract the settlement trough feature parameters; Weight allocation module: Converts the difference between the real-time mileage of the tunnel boring machine and each monitoring section into the ring number difference, divides each monitoring section into different control sections according to the ring number difference, and dynamically allocates the earth pressure adjustment weight coefficient and the grouting control weight coefficient to each control section. Command output module: The characteristic parameters of the settlement trough of each monitoring section are weighted and fused into earth pressure adjustment reference values ​​and grouting volume adjustment reference values. Within the weight switching range, the module smoothly transitions according to the degree of thrust disturbance and outputs dynamic adjustment commands for the tunnel boring machine excavation parameters.

[0007] Furthermore, the method for determining the critical value of earth pressure failure is as follows: Historical control records of the current tunneling strata are retrieved from the shield tunneling history database to construct earth pressure regulation sequences and thrust response sequences, and the correlation is achieved by using the adjustment time as the primary key. Calculate the settlement improvement rate for each earth pressure adjustment event, and select samples with positive earth pressure adjustment amplitudes to form the analysis dataset; The pressurization events in the analysis dataset are grouped according to the number of rings passed, and the average settlement improvement rate of the pressurization events within each ring number interval is calculated. The relationship curve between the number of rings passed and the settlement improvement rate is plotted. On the relationship curve of number of rings and settlement improvement rate, identify the first critical number of rings, and at the same time calculate the slope between each adjacent point on the relationship curve of number of rings and settlement improvement rate, and identify the second critical number of rings based on the decrease in slope. If the difference between the first critical ring number and the second critical ring number is within 0.5 rings, then the average of the two is taken as the critical value for earth pressure failure; otherwise, the smaller of the two is taken as the critical value for earth pressure failure.

[0008] Furthermore, the division method for the face-affected period and the shield tail exit period is as follows: For each earth pressure adjustment, a response time window is set, samples with a number of loops less than or equal to zero are collected and integrated into a baseline dataset, the maximum thrust change rate of each sample is extracted, and a normal disturbance threshold is set. The mileage of the center point of the tunnel boring machine cutterhead is recorded in real time, and the moment when the mileage of the center point of the cutterhead equals the mileage of the monitoring section is marked as the passing time of the monitoring section. The start time of the face influence period is the passing time minus the five-ring time offset, and the end time is the passing time. The start time of the shield tail release period is the passing time plus the earth pressure failure critical value time offset, and the end time is the passing time plus the ten-ring time offset.

[0009] Furthermore, the method for determining whether there is a risk of mis-controlling earth pressure is as follows: Search all pressure-increasing events during the shield tail release period and calculate the settlement improvement rate of each event. Mark events with a settlement improvement rate less than or equal to the invalidity judgment threshold as invalid control events. Calculate the proportion of invalid control. If it is greater than the invalidity proportion threshold, the increase in earth pressure is determined to be invalid. For each invalid control event, a mechanical response observation window is set. The maximum thrust change rate and the peak value of the comprehensive attitude deviation are read within the mechanical response observation window. If the maximum thrust change rate is greater than the normal disturbance threshold and the peak value of the comprehensive attitude deviation is greater than the allowable attitude angle deviation, it is marked as a harmful disturbance event. The proportion of harmful disturbances is statistically analyzed. If it is greater than or equal to the threshold for the proportion of harmful disturbances, it is determined that the increased earth pressure has caused harmful disturbances. Calculate the ratio of the pressure regulation frequency during the face influence period to the pressure regulation frequency during the shield tail exit period. If the ratio is greater than or equal to the judgment threshold, it is determined that the system does not have the ability to identify spatial location. If it is determined that increased earth pressure has caused harmful disturbances and the system lacks spatial location identification capabilities, then it is determined that there is a risk of mis-controlling earth pressure.

[0010] Furthermore, the process of real-time fitting of the cross-section of the surface subsidence trough at the monitoring section is as follows: Obtain the number and corresponding mileage of each monitoring section, switch the data acquisition channel corresponding to the monitoring section number to fine acquisition mode, and increase the acquisition frequency of surface settlement data, shield machine attitude parameters and propulsion cylinder pressure. For each monitoring section, the surface elevation values ​​of each monitoring point are collected and the cumulative settlement is calculated. The settlement values ​​are arranged according to the location of the monitoring points to form a settlement value sequence. Read the horizontal attitude angle, vertical attitude angle and roll angle of the tunnel boring machine, as well as the pressure value of the propulsion cylinder in each section and calculate the total thrust of the propulsion cylinder; The Peck formula was used as the fitting model, and the least squares method was used to perform nonlinear fitting on the settlement value sequence to obtain the settlement trough fitting model.

[0011] Furthermore, the extraction process of the characteristic parameters of the settling tank is as follows: The maximum settlement value and settlement trough width coefficient are extracted from the fitted parameters. The settlement trough volume is obtained by lateral integration of the fitted curve. The maximum settlement value, settlement trough width coefficient, and settlement trough volume are correlated with the section number, current time, tunnel boring machine mileage, and number of rings passed to form a settlement trough feature record, which is continuously updated according to a preset cycle.

[0012] Furthermore, the process of converting the difference between the real-time mileage of the tunnel boring machine and the monitoring sections into the difference in the number of rings is as follows: The real-time mileage station number of the cutterhead center point is continuously read. The mileage difference is obtained by subtracting the current mileage station number of the cutterhead center point from the mileage station number of the monitored section. The mileage difference is then divided by the width of a single ring segment to obtain the ring number difference.

[0013] Furthermore, the method for dynamically allocating the earth pressure adjustment weight coefficient and the grouting control weight coefficient to each control section is as follows: When the difference in the number of rings is greater than zero, it is the area affected by the working face. The earth pressure adjustment weight coefficient is set to the maximum value, and the grouting control weight coefficient is set to zero. When the difference in the number of rings is between the negative critical number of earth pressure rings and zero, it is a transition switching zone. The earth pressure adjustment weight coefficient is equal to one minus the transition progress, the grouting control weight coefficient is equal to the transition progress, and the transition progress is equal to the absolute value of the difference in the number of rings divided by the critical number of earth pressure rings. When the difference in the number of rings is less than or equal to the negative critical number of earth pressure rings, it is the shield tail grouting control zone. The earth pressure adjustment weight coefficient is set to zero, and the grouting control weight coefficient is set to the maximum value of one. According to the preset control cycle, the ring number difference and weight coefficient of each section are recalculated based on the updated tunnel boring machine mileage.

[0014] Furthermore, the calculation process for the earth pressure adjustment reference value and the grouting volume adjustment reference value is as follows: Read the maximum settlement value, settlement trough width coefficient, and settlement trough volume of each monitoring section at the current moment; Set up settlement-earth pressure mapping function and settlement-grouting mapping function, substitute the settlement trough characteristic parameters of each monitoring section into the two mapping functions respectively, and obtain the earth pressure adjustment contribution value and grouting volume adjustment contribution value of each section. The earth pressure adjustment reference value is obtained by multiplying the earth pressure adjustment contribution value of each section by its earth pressure adjustment weight coefficient and then summing them. The grouting volume adjustment reference value is obtained by multiplying the grouting volume adjustment contribution value of each section by its grouting control weight coefficient and then summing them.

[0015] Furthermore, the output process of the dynamic adjustment command for the tunnel boring machine's excavation parameters is as follows: If there exists a section whose current ring number difference is within the range of negative critical ring number plus or minus 0.5 rings, it is determined to be in the weight switching interval; otherwise, it is not in the weight switching interval. Read the current rate of change of total thrust of the propulsion cylinder and divide it by the normal disturbance threshold to obtain the ratio; If the weight switching interval is in the range and the ratio is greater than or equal to the preset disturbance concern threshold, then the smooth transition processing is enabled. The smooth transition time window is set, and the earth pressure adjustment reference value and the grouting volume adjustment reference value are slowly changed from the current value to the target value in the form of an S-shaped curve before being output. If the ratio is less than the disturbance concern threshold, the calculated value is output directly. If it is not in the weight switching interval, the calculated value is output directly.

[0016] The beneficial effects of this invention are as follows: Based on the correlation analysis of historical pressure rise events and settlement improvement rate, the critical value of earth pressure failure under the current geological conditions is adaptively determined, replacing the traditional fixed three-ring empirical value. This allows the division between the face influence period and the shield tail exit period to be automatically adjusted according to changes in geological conditions, avoiding control timing deviations caused by unreasonable fixed boundaries and improving the system's adaptability in different geological formations. Based on the difference in the number of rings between the current position of the tunnel boring machine and the monitoring section, each section is dynamically divided into the face influence zone, the transition switching zone, and the tail grouting control zone. Earth pressure adjustment weight and grouting control weight are assigned to each section respectively. In particular, a linear transition mechanism is adopted in the transition switching zone, so that the transfer of control authority from earth pressure to grouting is gradual rather than abrupt, effectively avoiding the control shock caused by traditional rigid switching. A smooth transition decision mechanism based on the degree of thrust disturbance was introduced. Within the weight switching interval, the system monitors the rate of change of the total thrust of the propulsion cylinder in real time. When the thrust disturbance approaches the historical disturbance boundary, an S-curve smooth transition is automatically activated, so that the control command changes gradually rather than abruptly. This mechanism effectively avoids the risk of attitude loss caused by amplification of sudden changes in control commands by the mechanical system. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1 This is a functional module diagram of the shield tunneling parameter dynamic adjustment system based on the morphology of surface settlement troughs of the present invention; Figure 2 This is the logic judgment diagram of the shield tunneling parameter dynamic adjustment system based on the morphology of surface settlement troughs in this invention. Figure 3 This is a comparison chart of the weighting coefficients of the present invention as a function of the difference in ring numbers; Figure 4 This is a graph showing the variation of the earth pressure and grouting volume adjustment reference values ​​of the present invention with the number of tunneling rings. Detailed Implementation

[0019] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0020] Example: Please refer to Figures 1-2 As shown, the shield tunneling parameter dynamic adjustment system based on the morphology of surface settlement troughs described in this invention specifically includes the following modules: Critical value determination module: Obtain historical pressure increase events and corresponding cross sections, and determine the critical value of earth pressure failure through correlation analysis by link number and settlement improvement rate; The process for determining the critical value of earth pressure failure includes: Retrieve historical control records of the current tunneling strata (identified by mileage segments) within the past 50 rings from the tunneling history database. This includes complete action information for each adjustment of the earth pressure setpoint, as well as the response of the tunnel boring machine's mechanical system to each earth pressure adjustment. The first point to clarify is that the earth pressure regulation sequence and thrust response sequence are constructed as follows: The earth pressure control sequence is formed by integrating the adjustment time, earth pressure before adjustment, earth pressure after adjustment, earth pressure adjustment range, and duration of each earth pressure setpoint adjustment in chronological order. The earth pressure adjustment range is the difference between the earth pressure after adjustment and the earth pressure before adjustment for each earth pressure adjustment, and the duration is the continuous duration during which the earth pressure setpoint remains unchanged after each adjustment. The corresponding adjustment time, response sampling time, lag time, thrust change rate, horizontal attitude deviation, vertical attitude deviation, and comprehensive attitude deviation for each adjustment of the earth pressure setpoint are integrated into a thrust response sequence in chronological order. The response sampling time is the actual time when the thrust response data is collected, which satisfies the condition that the response sampling time = the corresponding adjustment time + Δt, where Δt ∈ [1,3] sampling periods. The lag time is the delay from the earth pressure adjustment to the collection of the thrust response. The thrust change rate is the first derivative of the total thrust F of the propulsion cylinder with respect to time within the response window, dF / dt. The horizontal attitude deviation is the attitude angle deviation of the shield machine in the horizontal direction (left and right) relative to the reference value before adjustment. The vertical attitude deviation is the attitude angle deviation of the shield machine in the vertical direction (up and down) relative to the reference value before adjustment. The comprehensive attitude deviation is the square root of the sum of the squares of the horizontal attitude deviation and the vertical attitude deviation. It should be noted that the earth pressure control sequence and the thrust response sequence are linked by adjusting the time as the primary key, forming a one-to-many mapping relationship between action and response; Secondly, it should be noted that the calculation of the settlement improvement rate and the construction of the analysis dataset are as follows: From the earth pressure control sequence and thrust response sequence, a complete record of each earth pressure adjustment event is extracted to form a sample record. Each sample includes: earth pressure adjustment magnitude, thrust response lag time, maximum thrust change rate (i.e., the maximum value of the first derivative of the total thrust of the propulsion cylinder with respect to time within the thrust and attitude response window), peak value of comprehensive attitude deviation (i.e., the maximum value of the square root of the sum of the squares of the horizontal and vertical deviations of the tunnel boring machine within the thrust and attitude response time window), average settlement rate of the two rings before adjustment, and average settlement rate of the three rings after adjustment. For each sample record, calculate the corresponding settlement improvement rate: Settlement improvement rate = (average settlement rate of the two rings before adjustment - average settlement rate of the three rings after adjustment) / absolute value of the settlement rate before adjustment. Only samples with positive earth pressure adjustment amplitude (i.e. pressure rise events) are selected from all samples to form an analysis dataset. For each pressure rise event in the analysis dataset, the number of rings (accurate to zero-one ring) that the monitoring section corresponding to the time of the pressure rise event has been passed by the tunnel boring machine is recorded, as well as the settlement improvement rate corresponding to the pressure rise event. All pressurization events in the analysis dataset are grouped according to the corresponding number of rings passed. The grouping interval is set at 0.5 rings, starting from negative three rings and ending at positive six rings, and is divided into several continuous intervals. For each ring number interval, the number of pressurization events falling into the ring number interval is counted, and the average settlement improvement rate of these pressurization events is calculated. The average settlement improvement rate within each ring number interval is used as the representative value of the interval. The curve of relationship between ring number and settlement improvement rate is plotted with the midpoint of the ring number interval as the x-axis and the average settlement improvement rate as the y-axis. On the curve of the relationship between the number of rings and the settlement improvement rate, starting from the position where the number of rings is zero, the average settlement improvement rate within the sliding window is calculated ring by ring. The attenuation threshold is set as the position of the number of rings when the average settlement improvement rate drops to 50% of the average value of the interval within the positive first ring. This position is marked as the first critical number of rings.

[0021] At the same time, the slope between each adjacent point on the curve is calculated, that is, the rate at which the settlement improvement rate changes with the number of rings. Starting from the position where the number of rings is zero, the curve moves backward point by point. When the slope of the adjacent interval decreases and the decrease exceeds the preset threshold for the first time, it is the starting point where the effectiveness of earth pressure adjustment begins to accelerate its decline, and is recorded as the second critical number of rings. The first critical ring number is compared with the second critical ring number. If the difference between the first critical ring number and the second critical ring number is within 0.5 rings, the average value of the first critical ring number and the second critical ring number is taken as the critical value of earth pressure failure. If the difference exceeds 0.5 rings, the smaller value between the first critical ring number and the second critical ring number is taken as the critical value of earth pressure failure. It should be noted that the purpose of determining the critical value of earth pressure failure is to determine the critical number of earth pressure adjustment from effective to ineffective under the current geological conditions by analyzing the relationship between the number of rings passing through and the settlement improvement rate of the pressure rise event. This critical value replaces the traditional fixed three-ring empirical value and serves as the core boundary parameter for dividing the face influence period and the shield tail disengagement period in the subsequent risk assessment module. Risk assessment module: Based on the critical value of earth pressure failure, the monitoring section is divided into the face influence period and the shield tail release period. Based on the settlement improvement rate and thrust change rate of the pressure rise event during the shield tail release period, combined with the comparative analysis of the pressure adjustment frequency during the face influence period and the shield tail release period, it is determined whether there is a risk of earth pressure miscontrol. The process of dividing the working face influence period and the shield tail disengagement period includes: For each earth pressure adjustment, a response time window is set starting from the moment of earth pressure adjustment. Specifically, the response time window is set to extend for sixty seconds from the moment of earth pressure adjustment. It should be noted that the response time window is set to sixty seconds based on engineering measurement data, which shows that the thrust response usually reaches its peak within fifteen to twenty-five seconds after adjustment, and the attitude response reaches its peak within twenty-five to forty seconds. The sixty-second window is sufficient to fully capture the peak responses of both, and will not be mixed with interference signals from subsequent human operations (such as the start of the segment assembly process). Samples of the working face that have not yet reached the monitoring section (with a passing loop number less than or equal to zero) are obtained from the sample records of earth pressure adjustment events and integrated into a benchmark dataset; Extract the maximum thrust change rate corresponding to each sample from the benchmark dataset, integrate them into a one-dimensional sequence according to time series, calculate the mean and standard deviation of the one-dimensional sequence, and use the mean plus twice the standard deviation as the normal disturbance threshold. Obtain the mileage markers of all surface monitoring sections laid out along the tunnel axis, that is, the position of each section on the tunnel axis, expressed in meters from the tunnel starting point, and arranged in ascending order of mileage, and assign a unique number to each section. During the tunnel boring machine's excavation process, the mileage marker of the center point of the cutterhead is recorded in real time. When the mileage marker of the center point of the cutterhead is equal to the mileage marker of a certain monitoring section, the corresponding time is the time when the tunnel boring machine's face is directly below the monitoring section, and this time is marked as the time when the monitoring section is passed. Since the tunneling speed of the tunnel boring machine is not constant, it is necessary to convert the ring number interval into a time interval. Specifically, the average tunneling time per ring (i.e., the time spent tunneling one ring of segment width) is obtained before and after the monitoring section is passed through. Taking the passing time as the reference zero point, we calculate backward: multiply five rings by the average tunneling time per ring to obtain the forward offset time. Calculate backward: multiply the earth pressure failure critical value by the average tunneling time per ring to obtain the backward offset starting point at the beginning of the shield tail release period. Multiply ten rings by the average tunneling time per ring to obtain the backward offset ending point at the end of the shield tail release period. Using the passing time as the dividing point, the various characteristic intervals of the monitoring section are determined, including: The tunnel face influence period begins at the time of passage minus the time offset corresponding to the fifth ring road, and ends at the time of passage. It represents the process of the tunnel boring machine's tunnel face advancing from a distance of five ring roads from the section to directly below the section. During this period, the surface settlement is mainly affected by the earth pressure support effect of the tunnel face. The shield tail exit period begins when the time of passage is added to the time offset corresponding to the earth pressure failure threshold, and ends when the time of passage is added to the time offset corresponding to the tenth ring. This indicates that the tunnel boring machine has completely passed through the section and the shield tail has exited more than three rings. The process for determining whether there is a risk of miscontrolling earth pressure includes: The first point to clarify is the validity analysis, which specifically includes: Search the shield tunneling construction records for all earth pressure setting value adjustment events during the shield tail exit period. For each earth pressure setting value adjustment found, only select events with a positive adjustment range (pressure increase events). For each selected pressure increase event, record the earth pressure adjustment time, the earth pressure setting value before adjustment, the earth pressure setting value after adjustment, the adjustment range, and the section number corresponding to the pressure increase event. For each pressurization event extracted during the shield tail disengagement period, the settlement improvement rate for each pressurization event is calculated according to the formula: Settlement improvement rate = (Average settlement rate of the two rings before adjustment - Average settlement rate of the three rings after adjustment) / Absolute value of the settlement rate before adjustment. The settlement improvement rate is compared with the invalidation threshold. If the settlement improvement rate is less than or equal to the invalidation threshold, the pressurization event is marked as an invalid control event; otherwise, it is marked as an effective control event. It should be noted that the invalidity threshold is used to determine whether a single pressurization event is an invalid control. When the settlement improvement rate is less than or equal to the invalidity threshold, it is considered invalid. The basis for setting the threshold is from engineering practice experience: when the settlement improvement rate is less than 5%, it can be considered as no significant improvement within the range of monitoring error and random fluctuations in construction. During the shield tail exit period, the proportion of ineffective control events among all pressure-increasing events is statistically analyzed to obtain the ineffective control percentage. The ineffective control percentage is then compared with the ineffective percentage threshold. If the ineffective control percentage is greater than the ineffective percentage threshold, the increase in earth pressure during the shield tail grouting stage is determined to be ineffective under the geological conditions. It should be noted that the invalidity percentage threshold is used to determine whether the conclusion that the increase in earth pressure during the shield tail grouting stage is invalid is valid. When the proportion of invalid control events in all pressure-increasing events during the shield tail exit period is greater than this threshold, it is determined to be invalid. The basis for setting this threshold is the majority rule principle: more than 60% of the pressure-increasing events are invalid, indicating that invalidity is a common feature of this stage rather than an isolated phenomenon. If this value is set too low, it is easy to make misjudgments due to sample fluctuations. If it is set too high, it may cover up the real systemic problems. 60% is a reasonable intermediate value that can effectively balance the risk of misjudgment and the risk of omission. Secondly, it should be noted that the hazard analysis is as follows: For each invalid control event, a fixed duration (the duration is related to the response characteristics of the tunnel boring machine's hydraulic system and structure, usually one to three minutes) is extended forward from the moment the invalid control event occurs as the starting point, serving as the mechanical response observation window. Within the mechanical response observation window, the real-time value of the total thrust of the propulsion cylinder is continuously read from the tunnel boring machine monitoring system. The rate of change of thrust with respect to time (i.e., the amount of thrust change per unit time) is calculated. The entire window is traversed to find the moment when the rate of change of thrust reaches its maximum value, and the maximum value of the rate of change of thrust is recorded. Within the same mechanical response observation window, the real-time values ​​of the horizontal and vertical attitude angles are continuously read from the shield machine guidance system. The offset relative to the reference attitude angle before the event occurs is calculated. The offsets are recorded for the horizontal and vertical directions respectively, and the comprehensive attitude offset is calculated. The entire window is traversed to find the moment when the comprehensive attitude offset reaches its maximum value, and the peak value of the comprehensive attitude offset is recorded. For any invalid control event, the maximum thrust change rate is compared with the normal disturbance threshold. If the maximum thrust change rate is greater than the normal disturbance threshold, the invalid control event is determined to constitute an excessive disturbance in terms of thrust. Obtain the pre-set allowable attitude angle offset value for the project, and compare the peak value of the overall attitude offset with the allowable attitude angle offset value. If the peak value of the overall attitude offset is greater than the allowable attitude angle offset value, then mark the invalid control event as a harmful disturbance event. The proportion of harmful disturbance events in all pressure-increasing events is statistically analyzed to obtain the proportion of harmful disturbances. The proportion of harmful disturbances is then compared with a harmful disturbance proportion threshold. If the proportion of harmful disturbances is greater than or equal to the harmful disturbance proportion threshold, it is determined that the increase in earth pressure has caused harmful disturbances. It should be noted that the harmful proportion threshold is used to determine whether the conclusion that increased earth pressure has caused harmful disturbance is valid. When the proportion of harmful disturbance events in all pressure-increasing events during the shield tail release period is greater than or equal to the harmful proportion threshold, it is considered harmful. The basis for setting it is the majority principle: if more than half of the pressure-increasing events cause harmful disturbance, it indicates that the behavior has general harmfulness. Setting the harmful proportion threshold at 50% is in line with the conservative principle of engineering risk management that the majority of harmful events are considered harmful. Thirdly, it should be noted that the voltage regulation frequency comparison analysis is as follows: The pressure adjustment frequency during the tunnel face influence period is obtained by proportionally calculating the total number of earth pressure adjustments during the tunnel face influence period to the length of the tunnel face influence period. The pressure adjustment frequency during the shield tail exit period is obtained by proportionally calculating the total number of earth pressure adjustments during the shield tail exit period to the length of the shield tail exit period. The pressure adjustment frequency during the shield tail exit period is then proportionally calculated to the pressure adjustment frequency during the tunnel face influence period to obtain the pressure adjustment frequency ratio. The voltage regulation frequency ratio is compared with the judgment threshold. If the voltage regulation frequency ratio is greater than or equal to the judgment threshold, the system is determined to lack spatial location recognition capability. It should be noted that the threshold is based on engineering judgment: if the system has spatial recognition capability, the pressure regulation frequency during the shield tail release period should be significantly lower than that during the face influence period, and the ratio should be significantly less than one; 0.8 means that the pressure regulation frequencies in the two stages are almost the same, with a difference of no more than 20%, which is insufficient to prove that the system can distinguish spatial location. This boundary value comes from the statistical analysis of a large number of shield tunneling pressure regulation behaviors. In systems without spatial recognition, the ratio is usually higher than 0.8. If it is determined that increasing earth pressure simultaneously causes harmful disturbances and the system lacks spatial location recognition capabilities, then it is determined that there is a risk of miscontrolling earth pressure due to spatial mismatch. It should be noted that the role of determining whether there is a risk of earth pressure miscontrol is as follows: based on the determination of the critical value, a comprehensive assessment from three dimensions is made to determine whether there is a risk of earth pressure miscontrol due to the automation system's failure to distinguish spatial location. This is the core of the entire system's decision-making. Feature extraction module: If present, perform real-time fitting of the surface settlement trough cross sections of each monitoring section to extract the settlement trough feature parameters; The process of real-time fitting of the cross-section of the surface subsidence trough at the monitoring section includes: Obtain the number and corresponding mileage station of each monitoring section, as well as the number of rings that the tunnel boring machine has passed through. Continuously read the real-time mileage station of the cutterhead center point from the tunnel boring machine's automatic guidance system, and record the total length that the tunnel boring machine has excavated at the current moment, expressed in meters from the tunnel starting point. Switch the data acquisition channel corresponding to the monitoring section number to the fine acquisition mode. Specifically, increase the sampling frequency of the surface settlement data of the monitoring section from the normal mode to the fine mode (e.g., from once per minute to once every ten seconds), and simultaneously increase the acquisition frequency of the shield machine attitude parameters and propulsion cylinder pressure. For non-monitoring sections, maintain the normal sampling frequency unchanged. For each monitoring section, the surface elevation values ​​of each monitoring point are collected in real time from all monitoring points set up on the ground surface of the monitoring section. The elevation values ​​of each monitoring point are compared with the initial values, the cumulative settlement of each point is calculated, and the cumulative settlement of each monitoring point on the same monitoring section is arranged according to the position of the measuring point (horizontal distance from the center line of the tunnel) to form a sequence of settlement values ​​of the monitoring section at the current moment. The following three attitude parameters are continuously read from the tunnel boring machine's guidance system: horizontal attitude angle (the angle by which the tunnel boring machine deviates from the design axis in the horizontal plane), vertical attitude angle (the pitch angle of the tunnel boring machine in the vertical plane), and roll angle (the angle by which the tunnel boring machine rotates around its own longitudinal axis). All three angles are recorded in milliradians. The pressure values ​​of the propulsion cylinders in each section are continuously read from the hydraulic control system of the tunnel boring machine. The pressure value of each section is multiplied by the effective area of ​​the corresponding cylinder piston to obtain the thrust value of each section. The thrust values ​​of all sections are then added together to obtain the total thrust of the propulsion cylinders. At the same time, the change process of the total thrust over time is recorded. The Peck formula was used as the fitting model for the cross-sectional morphology of the surface settlement trough. The lateral position of each measuring point in the settlement value sequence was used as the independent variable, and the cumulative settlement of each measuring point was used as the dependent variable. The least squares method was used to perform nonlinear fitting of the Peck formula, that is, to find a set of parameters that minimizes the sum of squares of the deviations between the theoretical settlement value calculated by the fitting formula and the actual monitoring value. The fitting calculation was completed iteratively through a numerical optimization algorithm to obtain the settlement trough fitting model. It should be noted that the basic mathematical form of Peck's formula is: The surface settlement at a certain measuring point is equal to the maximum settlement directly above the tunnel at that cross section multiplied by an exponential function with the natural constant e as the base. The exponent of this exponential function is negative, the numerator is the square of the lateral distance of the measuring point from the tunnel centerline, and the denominator is the square of twice the settlement trough width coefficient. In engineering terms: On the cross section of a tunnel, the settlement at each point on the ground surface exhibits a bell-shaped distribution along the transverse direction, with the largest amount in the middle and the amount gradually decreasing on both sides. This distribution pattern can be described by a Gaussian normal distribution curve. The meanings of the parameters in the formula are as follows: Maximum settlement: The settlement value at the ground surface directly above the tunnel centerline is the location with the largest settlement among all measuring points in this section, and the unit is millimeters. It reflects the total amount of stratum loss at this section. Settlement trough width coefficient: a parameter reflecting the lateral influence range of the settlement trough, in meters. The larger the value, the wider the range of settlement influence, that is, the larger the radius of influence of tunnel construction on the surrounding surface. The smaller the value, the narrower the influence range, indicating that the settlement is concentrated near the tunnel. Lateral distance of measuring point: The vertical distance from a surface monitoring point along the horizontal direction to the center line of the tunnel, in meters. The value is zero at the point directly above the tunnel, and positive values ​​are taken for measuring points on both sides. The core physical meaning of Peck's formula is that the cross-sectional shape of the surface settlement trough approximately follows a normal distribution (i.e., Gaussian distribution). The settlement is greatest directly above the tunnel. As the distance from the tunnel centerline increases, the settlement gradually decreases according to an exponential law, and at a sufficiently far distance, it decreases to near zero. This shape reflects the propagation law of ground disturbance caused by shield tunnel construction. The stress release caused by tunnel excavation is transmitted from the tunnel to the surrounding strata. The closer to the tunnel, the greater the disturbance, and the farther away from the tunnel, the smaller the disturbance. The extraction process of the characteristic parameters of the settling tank includes: The maximum settlement value and settlement trough width coefficient are extracted from the fitting parameters of the settlement trough fitting model. Based on the settlement trough shape curve obtained by fitting, the settlement amount in this range is integrated laterally with the tunnel centerline as the zero point until the settlement value decays to near zero. The volume of the settlement trough is obtained. The maximum settlement value, settlement trough width coefficient, settlement trough volume are correlated with the corresponding monitoring section number, current time, current tunnel boring machine mileage, and the number of rings that have been passed through the section to form a settlement trough characteristic record of the monitoring section at the current time. According to the preset fine collection cycle, the characteristic parameters of the settlement trough of each monitoring section are continuously updated; It should be noted that the purpose of extracting the feature parameters of the settlement trough is to switch the surface settlement data of the risk section to the fine acquisition mode, use the Peck formula and the least squares method to fit the cross section of the settlement trough in real time, and extract three feature parameters: maximum settlement value, settlement trough width coefficient and settlement trough volume, so as to provide data input for subsequent weight allocation. Weight allocation module: Converts the difference between the real-time mileage of the tunnel boring machine and each monitoring section into the ring number difference, divides each monitoring section into different control sections according to the ring number difference, and dynamically allocates the earth pressure adjustment weight coefficient and the grouting control weight coefficient to each control section. The process of converting the difference between the real-time mileage of the tunnel boring machine and the monitoring sections into the difference in the number of rings includes: The real-time mileage marker of the cutterhead center point is continuously read, and the total length of tunnel excavation by the shield machine at the current moment is recorded in meters from the tunnel start point. The real-time mileage marker and the total length of tunnel excavation by the shield machine at the current moment are dynamically updated real-time values, and must be read again in each control cycle. For each surface monitoring section, the mileage difference is obtained by subtracting the current mileage of the shield machine cutterhead center point from the mileage of the monitoring section. It is understandable that the physical meaning of the mileage difference is as follows: if the mileage difference is positive, it means that the shield machine cutterhead has not yet reached the monitoring section, and the monitoring section is located in front of the shield machine; if the mileage difference is zero, it means that the shield machine cutterhead is directly below the monitoring section; if the mileage difference is negative, it means that the shield machine cutterhead has passed the monitoring section, and the monitoring section is located behind the shield machine. Its absolute value is the distance that the shield machine has exceeded. Divide the mileage difference by the width of a single ring segment to obtain the difference in the number of rings of the monitoring section relative to the current position of the tunnel boring machine; The process of dividing each monitoring section into different control zones based on the difference in the number of rings includes: Based on the calculated difference in the number of rings, each monitoring section is divided into one of the following stages: If the difference in the number of rings is greater than zero, it means that the tunnel boring machine has not yet reached the section and the section is in front of the tunnel face; if the difference in the number of rings is equal to zero, it means that the tunnel boring machine is passing directly below the section and is in the process of crossing; if the difference in the number of rings is between the negative earth pressure failure threshold and zero (excluding zero), it means that the tunnel boring machine has passed the section but the number of rings passed is less than three and it is in the transition stage between the shield shell passing and the shield tail just exiting; if the difference in the number of rings is less than or equal to the negative earth pressure failure threshold, it means that the tunnel boring machine has passed more than three rings of the section and the section has fully entered the shield tail exiting stage. The allocation process of the earth pressure adjustment weight coefficient and the grouting control weight coefficient includes: Based on the impact mechanism of different stages of shield tunneling on surface settlement, each monitoring section is divided into three control zones according to the difference in the number of rings, and each zone is assigned a different weight combination. The basis for the division of the three zones and the corresponding weight allocation logic are as follows: When the difference in the number of rings is greater than zero, it is located in the influence zone of the tunnel face. The surface settlement of the monitoring section is mainly determined by the earth pressure support effect of the tunnel face. The earth pressure adjustment weight coefficient is taken as the maximum value of one, and the grouting control weight coefficient is taken as zero. When the difference in the number of rings is between the negative critical number of earth pressure rings and zero, it is located in the transition switching zone. First, the transition progress is calculated. The transition progress is equal to the absolute value of the difference in the number of rings at the monitoring section divided by the critical number of earth pressure rings. The earth pressure adjustment weight coefficient is equal to one minus the transition progress. The grouting control weight coefficient is equal to the transition progress. When the difference in the number of rings is less than or equal to the negative critical number of earth pressure rings, it is located in the shield tail grouting control zone. The settlement development of the monitoring section depends entirely on the grouting filling density of the shield tail void. The earth pressure adjustment weight coefficient is zero, and the grouting control weight coefficient is the maximum value of one. The section number of each monitoring section, the current ring number difference of the monitoring section, the control section type of the monitoring section, the allocated earth pressure adjustment weight coefficient, and the allocated grouting control weight coefficient are associated to form a weight allocation record for the current control cycle of the monitoring section. According to the preset control cycle, the ring difference and weight coefficient of each section are recalculated based on the updated shield machine mileage to ensure that the weight allocation is always synchronized with the current spatial position of the shield machine. For example, such as Figure 3 As shown, Figure 3 The chart shows the changes in weight coefficients with the difference in the number of rings. It lists the earth pressure adjustment weight coefficient and grouting control weight coefficient assigned by the system to each monitoring section under different differences in the number of rings. When the difference in the number of rings is greater than zero (such as 0.5 rings and 1 ring in the table), the section is in the influence zone of the tunnel face. The earth pressure adjustment weight is taken as the maximum value of 1, and the grouting control weight is taken as 0. This indicates that the settlement of the section is mainly controlled by the earth pressure support effect of the tunnel face. When the difference in the number of rings is less than or equal to the negative earth pressure failure threshold (the earth pressure failure threshold in the table is taken as 1.10 rings, so -1.5 rings and below), the section enters the shield tail grouting control zone. The weight allocation is completely reversed. The earth pressure adjustment weight is taken as 0, and the grouting control weight is taken as 1. This means that the settlement of the section is completely dependent on the grouting filling density of the shield tail gap. In the transition switching zone (such as -0.5 rings in the table), the weight coefficient changes linearly with the transition progress. The earth pressure adjustment weight and the grouting control weight each account for 0.5, realizing the gradual transfer of control authority from earth pressure to grouting. It should be noted that the function of dynamically allocating the earth pressure adjustment weight coefficient and the grouting control weight coefficient is to convert the difference between the real-time mileage of the tunnel boring machine and the mileage of each monitoring section into the ring number difference. Based on the ring number difference, each section is divided into three control sections: the face influence zone, the transition switching zone, and the tail grouting control zone. The earth pressure adjustment weight coefficient and the grouting control weight coefficient are then allocated to each section to achieve a smooth transfer of control authority from earth pressure to grouting. Command output module: The characteristic parameters of the settlement trough of each monitoring section are weighted and fused into earth pressure adjustment reference values ​​and grouting volume adjustment reference values. Within the weight switching range, the parameters are smoothly transitioned according to the thrust disturbance level, and the dynamic adjustment command of the tunnel boring machine tunneling parameters is output. The process of weightedly fusing the settlement trough characteristic parameters of each monitoring section into earth pressure adjustment reference values ​​and grouting volume adjustment reference values ​​includes: Read the current time-specific characteristic parameters of the settlement trough for each monitoring section: maximum settlement value, settlement trough width coefficient, and settlement trough volume; Two mapping functions are defined: the settlement-earth pressure mapping function is used to convert the characteristic parameters of the settlement trough into earth pressure adjustment amounts, and the settlement-grouting mapping function is used to convert the characteristic parameters of the settlement trough into grouting volume adjustment amounts. Specifically, the earth pressure adjustment is based on the deviation of the maximum settlement value from the target value as the main control item, and the settlement trough width coefficient and settlement trough volume as auxiliary correction items. The grouting volume adjustment is based on the settlement trough volume as the main control item, and the maximum settlement value and settlement trough width coefficient as auxiliary correction items. The initial values ​​of each proportional coefficient are determined by the geological category analogy method. During construction, feedback correction is performed based on the deviation between the predicted effect and the actual effect. The correction step size is five percent of the current coefficient value. It is executed at most once per control cycle to continuously optimize the mapping function parameters. The two mapping functions are set independently and coordinated through the weight allocation module to achieve an independent conversion and weighted fusion control architecture. The mathematical form of the settlement-earth pressure mapping function is: ΔP = k1 × (S_max - S_target) + k2 × (V_s - V_target) + k3 × (i - i_target), where ΔP is the earth pressure adjustment reference value (unit: kPa), S_max is the real-time maximum settlement value (unit: mm), S_target is the settlement target value, which is the allowable settlement amount specified in the design document, and V_s is the volume of the settlement trough (unit: m). 3 V_target is its corresponding volume target value, i is the settling tank width coefficient, i_target is its design estimate, and k1, k2, and k3 are mapping coefficients; The mathematical form of the settlement-grouting mapping function is: ΔG=m1×(V_s-V_target)+m2×(S_max-S_target)+m3×(i-i_target), where ΔG is the reference value for adjusting the grouting volume (unit: L / min), and m1, m2, and m3 are the mapping coefficients; For each monitoring section, the settlement trough characteristic parameters of the monitoring section are substituted into two mapping functions to obtain the earth pressure adjustment contribution value and the grouting volume adjustment contribution value of the monitoring section. Multiply the earth pressure adjustment contribution value of each monitoring section by its corresponding earth pressure adjustment weight coefficient, and then add the products of all monitoring sections to obtain the earth pressure adjustment reference value. Multiply the grouting volume adjustment contribution value of each monitoring section by the corresponding grouting control weight coefficient, and then add the products of all monitoring sections to obtain the grouting volume adjustment reference value. For example, taking a shield tunnel section of a subway in a certain city as an example, the tunnel outer diameter D=6.2m, the width of a single ring segment is 1.2m, the current excavation depth Z=18m, and the stratum is plastic to stiff plastic silty clay. The design allowable settlement for this section is +30mm (with downward settlement as positive, i.e., the maximum allowable downward settlement is 30mm). From the design documents, the expected settlement trough width coefficient at this depth is found to be 0.5×Z=9m, and the target value of the settlement trough volume is 2.5×expected settlement trough width coefficient×allowable settlement=2.5×9×0.03=0.675m. 3In the formula, 0.03m is the conversion of 30mm to meters, and 2.5 is a proportionality constant; The system, in fine-grained acquisition mode, obtained the following real-time fitting parameters for the monitoring section: maximum settlement value = 52 mm, settlement trough width coefficient = 11.5 m, and settlement trough volume = 1.45 m³. 3 ; Subtracting the measured values ​​from the target values ​​yields the deviation terms: Maximum settlement deviation = 52 - 30 = +22 mm (actual settlement is greater than the allowable value, positive deviation); Settling tank volume deviation = 1.45 - 0.675 = +0.775 mm 3 (Positive deviation); The deviation of the settlement trough width coefficient = 11.5 - 9 = +2.5m (the settlement influence range is wider than expected). Substituting the above deviation term into the settlement-earth pressure mapping function, we get ΔP = 155.35 kPa. That is, without considering the intervention of the weighting coefficient, the earth pressure adjustment contributed by this section alone is +155.35 kPa (a positive value indicates that the earth pressure setting value needs to be increased). Substituting the same deviation term into the settlement-grouting mapping function, we get ΔG = 361.5 L / min, which means that the grouting volume adjustment value contributed by this section alone is +361.5 L / min (a positive value indicates that the synchronous grouting flow rate needs to be increased). At this point, the difference in the number of rings between the center point of the tunnel boring machine cutterhead and the monitoring section is -2.5 rings, which is less than the negative earth pressure failure threshold (the threshold under this condition was determined to be -2.0 rings based on previous analysis). Therefore, this section has completely entered the tail grouting control zone. According to the weight allocation logic, the earth pressure adjustment weight coefficient for this section is 0, and the grouting control weight coefficient is 1. The final output values ​​to the tunnel boring machine control system are: final output value of earth pressure adjustment = 0, and final output value of grouting volume adjustment = +361.5L / min. It should be noted that the earth pressure adjustment reference value and the grouting volume adjustment reference value represent the earth pressure adjustment range and the grouting volume adjustment range recommended by the system after comprehensively considering the settlement status of all monitoring sections within the current control period. For example, such as Figure 4 As shown, Figure 4The diagram illustrates the variation of earth pressure and grouting volume adjustment reference values ​​with the number of tunneling rings. It lists the final weighted and fused earth pressure adjustment reference values ​​(kPa) and grouting volume adjustment reference values ​​(L) output by the system under different tunneling ring numbers (i.e., ring difference). When the ring difference is positive (e.g., 0.5 ring, 1.0 ring in the table), the corresponding section is in the tunnel face influence zone, and the earth pressure adjustment weight coefficient is set to its maximum value of 1. The system outputs an effective earth pressure adjustment reference value (62-65 kPa) based on the settlement trough characteristic parameters (e.g., maximum settlement value) through the settlement-earth pressure mapping function to achieve active control of the tunnel face support effect. At this time, the grouting control weight coefficient is 0, and the grouting volume adjustment reference value is zero. When the ring difference changes from... When the positive to negative value reaches 0.0 ring, the cross-section is at the critical crossing point. The earth pressure adjustment reference value is still maintained at 60 kPa to ensure the stability of the strata during the tunnel crossing process. When the difference in the number of rings is less than or equal to the negative earth pressure failure critical value (in this example, the critical value is 1.0 ring, so -1.0 ring and below), the cross-section completely enters the shield tail grouting control zone. The earth pressure adjustment weight coefficient is 0, and the earth pressure adjustment reference value is zero. This fundamentally avoids the risk of erroneously activating the earth pressure adjustment command due to spatial mismatch during the shield tail grouting stage. At the same time, the grouting volume adjustment reference value is 0 in this example working condition, indicating that the characteristic parameters of the settlement trough of each cross-section (such as the settlement trough volume) have become stable at the corresponding tunneling position or no additional grouting filling is required. The output process of the dynamic adjustment command for the tunnel boring machine's tunneling parameters includes: If there exists a section where the current ring number difference is within the range of the negative critical ring number plus or minus 0.5 rings, then the system is determined to be in the weight switching interval. Read the rate of change of the total thrust of the propulsion cylinder with time at the current moment, divide the current rate of change of thrust by the normal disturbance threshold, and obtain the ratio; If it is determined that we are currently in a weight switching interval, then the following perturbation prediction logic is executed: The ratio is compared with the preset disturbance concern threshold. If the ratio is greater than or equal to the disturbance concern threshold, it indicates that the current thrust change has approached or exceeded the historical disturbance boundary. The command step during the switching process may trigger or aggravate attitude loss of control. In this case, smooth transition processing needs to be enabled. Otherwise, no additional smoothing processing is required. It should be noted that the disturbance concern threshold is set based on the engineering conservative principle: 0.8 is 80% of the normal disturbance threshold. The value is set below 1 to reserve a safety margin. When the disturbance has not yet reached the threshold but is close to it, early intervention is provided to prevent the disturbance from continuing to develop into an excessive state, thus realizing the transformation from passive response to active prevention. If it is determined that the current period is not in the weight switching interval, then regardless of the ratio, the disturbance prediction mechanism will not be triggered, and the control command will be executed directly. When it is determined that a smooth transition needs to be enabled, a smooth transition time window is set. Within the smooth transition time window, the earth pressure adjustment reference value and the grouting volume adjustment reference value are changed slowly from the current value to the target value in the form of an S-shaped curve, rather than jumping to the target value instantaneously. If a smooth transition is not required, the calculated earth pressure adjustment reference value and grouting volume adjustment reference value will be directly used as the final control command output. If a smooth transition is required, the current cycle execution value after the S-curve gradual change process will be used as the final control command output. It should be noted that the function of the output shield tunneling parameter dynamic adjustment command is as follows: the characteristic parameters of the settlement trough of each section are converted into control contribution values ​​through a mapping function, multiplied by the corresponding weight coefficient, and then weighted and summed to obtain the earth pressure adjustment reference value and the grouting volume adjustment reference value. Within the weight switching interval, the decision on whether to enable smooth transition is made based on the current thrust disturbance level, and finally outputs a stable tunneling parameter adjustment command, which is the execution end of the entire control process.

[0022] The technical solution and advantages of this application are as follows: Historical pressure-increasing events and corresponding cross-sections are obtained, and the earth pressure failure threshold is determined through correlation analysis using the number of rings and the settlement improvement rate. Based on the earth pressure failure threshold, the monitoring cross-sections are divided into the face-affected period and the shield tail exit period. Based on the settlement improvement rate and thrust change rate of pressure-increasing events during the shield tail exit period, combined with a comparative analysis of the pressure regulation frequency during the face-affected period and the shield tail exit period, it is determined whether there is a risk of mis-controlling earth pressure. If so, the surface settlement trough of each monitoring cross-section is cross-sectionally analyzed. The system performs real-time fitting to extract the characteristic parameters of the settlement trough; it converts the difference between the real-time mileage of the tunnel boring machine and each monitoring section into a ring difference, and divides each monitoring section into different control segments based on the ring difference. It then dynamically assigns earth pressure adjustment weight coefficients and grouting control weight coefficients to each control segment. The characteristic parameters of the settlement trough of each monitoring section are weighted and fused into earth pressure adjustment reference values ​​and grouting volume adjustment reference values. Within the weight switching interval, the system smoothly transitions according to the thrust disturbance level and outputs dynamic adjustment commands for the tunnel boring machine's excavation parameters. This invention determines the critical value of earth pressure failure by analyzing the correlation between the number of rings passed through historical pressure-increasing events and the settlement improvement rate. Based on the critical value of earth pressure failure, it divides the face influence period and the shield tail disengagement period, and judges the risk of earth pressure miscontrol from three aspects: effectiveness, harmfulness, and pressure adjustment frequency. It switches the risk section to a fine acquisition mode, uses the Peck formula to fit the cross section of the settlement trough and extracts characteristic parameters. According to the difference in the number of rings, the section is divided into different control sections and weight coefficients are dynamically assigned. Through weighted fusion, reference values ​​for earth pressure adjustment and grouting volume adjustment are generated. In the weight switching interval, a smooth transition strategy is decided based on the degree of thrust disturbance, realizing the precise and stable adjustment of shield tunneling parameters and effectively controlling surface settlement.

[0023] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made in accordance with the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A dynamic adjustment system for shield tunneling parameters based on the morphology of surface settlement troughs, characterized in that: Includes the following modules: Critical value determination module: Obtain historical pressure increase events and corresponding cross sections, and determine the critical value of earth pressure failure through correlation analysis by link number and settlement improvement rate; Risk assessment module: Based on the critical value of earth pressure failure, the monitoring section is divided into the face influence period and the shield tail release period. Based on the settlement improvement rate and thrust change rate of the pressure rise event during the shield tail release period, combined with the comparative analysis of the pressure adjustment frequency during the face influence period and the shield tail release period, it is determined whether there is a risk of earth pressure miscontrol. Feature extraction module: If present, perform real-time fitting of the surface settlement trough cross sections of each monitoring section to extract the settlement trough feature parameters; Weight allocation module: Converts the difference between the real-time mileage of the tunnel boring machine and each monitoring section into the ring number difference, divides each monitoring section into different control sections according to the ring number difference, and dynamically allocates the earth pressure adjustment weight coefficient and the grouting control weight coefficient to each control section. Command output module: The characteristic parameters of the settlement trough of each monitoring section are weighted and fused into earth pressure adjustment reference values ​​and grouting volume adjustment reference values. Within the weight switching range, the module smoothly transitions according to the degree of thrust disturbance and outputs dynamic adjustment commands for the tunnel boring machine excavation parameters.

2. The shield tunneling parameter dynamic adjustment system based on surface settlement trough morphology according to claim 1, characterized in that: The method for determining the critical value of earth pressure failure is as follows: Historical control records of the current tunneling strata are retrieved from the shield tunneling history database to construct earth pressure regulation sequences and thrust response sequences, and the correlation is achieved by using the adjustment time as the primary key. Calculate the settlement improvement rate for each earth pressure adjustment event, and select samples with positive earth pressure adjustment amplitudes to form the analysis dataset; The pressurization events in the analysis dataset are grouped according to the number of rings passed, and the average settlement improvement rate of the pressurization events within each ring number interval is calculated. The relationship curve between the number of rings passed and the settlement improvement rate is plotted. On the relationship curve of number of rings and settlement improvement rate, identify the first critical number of rings, and at the same time calculate the slope between each adjacent point on the relationship curve of number of rings and settlement improvement rate, and identify the second critical number of rings based on the decrease in slope. If the difference between the first critical ring number and the second critical ring number is within 0.5 rings, then the average of the two is taken as the critical value for earth pressure failure; otherwise, the smaller of the two is taken as the critical value for earth pressure failure.

3. The shield tunneling parameter dynamic adjustment system based on surface settlement trough morphology according to claim 1, characterized in that: The method for dividing the face-affected period and the shield tail disengagement period is as follows: For each earth pressure adjustment, a response time window is set, samples with a number of loops less than or equal to zero are collected and integrated into a baseline dataset, the maximum thrust change rate of each sample is extracted, and a normal disturbance threshold is set. The mileage of the center point of the tunnel boring machine cutterhead is recorded in real time, and the moment when the mileage of the center point of the cutterhead equals the mileage of the monitoring section is marked as the passing time of the monitoring section. The start time of the face influence period is the passing time minus the five-ring time offset, and the end time is the passing time. The start time of the shield tail release period is the passing time plus the earth pressure failure critical value time offset, and the end time is the passing time plus the ten-ring time offset.

4. The shield tunneling parameter dynamic adjustment system based on surface settlement trough morphology according to claim 3, characterized in that: The method for determining whether there is a risk of mis-controlling earth pressure is as follows: Search all pressure-increasing events during the shield tail release period and calculate the settlement improvement rate of each event. Mark events with a settlement improvement rate less than or equal to the invalidity judgment threshold as invalid control events. Calculate the proportion of invalid control. If it is greater than the invalidity proportion threshold, the increase in earth pressure is determined to be invalid. For each invalid control event, a mechanical response observation window is set. The maximum thrust change rate and the peak value of the comprehensive attitude deviation are read within the mechanical response observation window. If the maximum thrust change rate is greater than the normal disturbance threshold and the peak value of the comprehensive attitude deviation is greater than the allowable attitude angle deviation, it is marked as a harmful disturbance event. The proportion of harmful disturbances is statistically analyzed. If it is greater than or equal to the threshold for the proportion of harmful disturbances, it is determined that the increased earth pressure has caused harmful disturbances. Calculate the ratio of the pressure regulation frequency during the face influence period to the pressure regulation frequency during the shield tail exit period. If the ratio is greater than or equal to the judgment threshold, it is determined that the system does not have the ability to identify spatial location. If it is determined that increased earth pressure has caused harmful disturbances and the system lacks spatial location identification capabilities, then it is determined that there is a risk of mis-controlling earth pressure.

5. The shield tunneling parameter dynamic adjustment system based on surface settlement trough morphology according to claim 1, characterized in that: The process of real-time fitting of the cross-section of the surface subsidence trough at the monitoring section is as follows: Obtain the number and corresponding mileage of each monitoring section, switch the data acquisition channel corresponding to the monitoring section number to fine acquisition mode, and increase the acquisition frequency of surface settlement data, shield machine attitude parameters and propulsion cylinder pressure. For each monitoring section, the surface elevation values ​​of each monitoring point are collected and the cumulative settlement is calculated. The settlement values ​​are arranged according to the location of the monitoring points to form a settlement value sequence. Read the horizontal attitude angle, vertical attitude angle and roll angle of the tunnel boring machine, as well as the pressure value of the propulsion cylinder in each section and calculate the total thrust of the propulsion cylinder; The Peck formula was used as the fitting model, and the least squares method was used to perform nonlinear fitting on the settlement value sequence to obtain the settlement trough fitting model.

6. The shield tunneling parameter dynamic adjustment system based on surface settlement trough morphology according to claim 1, characterized in that: The extraction process of the characteristic parameters of the settling tank is as follows: The maximum settlement value and settlement trough width coefficient are extracted from the fitted parameters. The settlement trough volume is obtained by lateral integration of the fitted curve. The maximum settlement value, settlement trough width coefficient, and settlement trough volume are correlated with the section number, current time, tunnel boring machine mileage, and number of rings passed to form a settlement trough feature record, which is continuously updated according to a preset cycle.

7. The shield tunneling parameter dynamic adjustment system based on surface settlement trough morphology according to claim 1, characterized in that: The process of converting the difference between the real-time mileage of the tunnel boring machine and the monitoring sections into the difference in the number of rings is as follows: The real-time mileage station number of the cutterhead center point is continuously read. The mileage difference is obtained by subtracting the current mileage station number of the cutterhead center point from the mileage station number of the monitored section. The mileage difference is then divided by the width of a single ring segment to obtain the ring number difference.

8. The shield tunneling parameter dynamic adjustment system based on surface settlement trough morphology according to claim 7, characterized in that: The method for dynamically allocating earth pressure adjustment weight coefficients and grouting control weight coefficients to each control section is as follows: When the difference in the number of rings is greater than zero, it is the area affected by the working face. The earth pressure adjustment weight coefficient is set to the maximum value, and the grouting control weight coefficient is set to zero. When the difference in the number of rings is between the negative critical number of earth pressure rings and zero, it is a transition switching zone. The earth pressure adjustment weight coefficient is equal to one minus the transition progress, the grouting control weight coefficient is equal to the transition progress, and the transition progress is equal to the absolute value of the difference in the number of rings divided by the critical number of earth pressure rings. When the difference in the number of rings is less than or equal to the negative critical number of earth pressure rings, it is the shield tail grouting control zone. The earth pressure adjustment weight coefficient is set to zero, and the grouting control weight coefficient is set to the maximum value of one. According to the preset control cycle, the ring number difference and weight coefficient of each section are recalculated based on the updated tunnel boring machine mileage.

9. The shield tunneling parameter dynamic adjustment system based on surface settlement trough morphology according to claim 1, characterized in that: The calculation process for the earth pressure adjustment reference value and the grouting volume adjustment reference value is as follows: Read the maximum settlement value, settlement trough width coefficient, and settlement trough volume of each monitoring section at the current moment; Set up settlement-earth pressure mapping function and settlement-grouting mapping function, substitute the settlement trough characteristic parameters of each monitoring section into the two mapping functions respectively, and obtain the earth pressure adjustment contribution value and grouting volume adjustment contribution value of each section. The earth pressure adjustment reference value is obtained by multiplying the earth pressure adjustment contribution value of each section by its earth pressure adjustment weight coefficient and then summing them. The grouting volume adjustment reference value is obtained by multiplying the grouting volume adjustment contribution value of each section by its grouting control weight coefficient and then summing them.

10. The shield tunneling parameter dynamic adjustment system based on surface settlement trough morphology according to claim 9, characterized in that: The output process of the dynamic adjustment command for the tunnel boring machine's excavation parameters is as follows: If there exists a section whose current ring number difference is within the range of negative critical ring number plus or minus 0.5 rings, it is determined to be in the weight switching interval; otherwise, it is not in the weight switching interval. Read the current rate of change of total thrust of the propulsion cylinder and divide it by the normal disturbance threshold to obtain the ratio; If the weight switching interval is in the range and the ratio is greater than or equal to the preset disturbance concern threshold, then the smooth transition processing is enabled. The smooth transition time window is set, and the earth pressure adjustment reference value and the grouting volume adjustment reference value are slowly changed from the current value to the target value in the form of an S-shaped curve before being output. If the ratio is less than the disturbance concern threshold, the calculated value is output directly. If it is not in the weight switching interval, the calculated value is output directly.

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