Water conservancy tunnel construction axis deviation real-time measurement method based on inertial navigation

Abstract

The invention relates to the technical field of tunnel construction, in particular to a water conservancy tunnel construction axis deviation real-time measurement method based on inertial navigation, which comprises the following steps: acquiring data based on a water conservancy tunnel construction section, identifying a key measurement area, tracking attitude angle change and correcting navigation reference, and extracting cross section structure change characteristics; and judging the main shaft direction offset and the spatial coincidence relation between the main shaft direction offset and the trigger section, and adjusting the sampling rule and the amplitude limiting boundary. According to the method, a synchronous analysis chain of an attitude angle and an acceleration sequence is established through continuous acquisition of inertial navigation data and dynamic recognition of a structural response signal in the water conservancy tunnel construction process, and a data circulation mechanism with attitude drift monitoring, section stable recognition and main shaft direction correction as the core is formed; and the deviation trend is identified through the spatial coincidence relation, a constraint correction interval is generated, closed-loop management of the axis trend, the posture change and the displacement deviation is formed, and it is ensured that the posture stability and the deviation controllable state are maintained in the tunnel closed environment.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a method for real-time measurement of axis deviation in hydraulic tunnel construction based on inertial navigation. Background Technology

[0002] Tunnel construction mainly includes tunnel axis layout, tunneling equipment guidance, tunnel geometric parameter measurement, and construction monitoring and measurement, forming a systematic engineering technology system integrating geological analysis, construction design, construction control, and acceptance measurement. Traditional tunnel axis measurement refers to measuring the positional deviation of construction sections segment by segment based on manual observation and photoelectric distance measurement principles using instruments such as total stations and laser guidance instruments, within an established control network. This method relies on unobstructed line of sight and manual operation. It typically employs methods such as optical angle measurement, prism reflection distance measurement, and three-dimensional coordinate transformation to solve the problem of obtaining deviations in hydraulic tunnel axis measurement.

[0003] Traditional hydraulic tunnel surveying relies on optical instruments and manual observation. In long-distance or tortuous sections, it is easily affected by line-of-sight obstruction, reflective surface offset, and environmental humidity, resulting in signal discontinuity and accumulation of distance measurement errors. In areas with frequent geological changes, it is difficult to update control points, and the measurement coordinate chain is prone to discontinuity. Attitude changes cannot be reflected in real time during the advancement stage. When the observation interval is long, the deviation data is corrected with lag, causing delays in axis judgment and cumulative direction errors. It is difficult to support continuous attitude tracking and real-time offset evaluation in a closed construction environment, which limits the response speed and spatial accuracy of the measurement. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a real-time measurement method for axis deviation in hydraulic tunnel construction based on inertial navigation.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a real-time measurement method for axis deviation in hydraulic tunnel construction based on inertial navigation, comprising the following steps: S1: Based on the construction section of the water conservancy tunnel, analyze the structural partition number and triaxial acceleration results, compare the difference in acceleration direction between the current and previous measurement points, determine the spatial distribution of acceleration changes, adjust the acquisition interval, and obtain the trigger section identifier set; S2: Based on the trigger segment identifier set, analyze the angular velocity changes collected by the inertial navigation device, monitor the attitude angle change trend, verify the attitude response, adjust the navigation reference, and obtain drift judgment reference items; S3: Based on the drift determination reference, identify the spatial coordinates of the cross-sectional center point of the key measurement area and the instantaneous measurement of the three-axis acceleration, determine the changes in the coordinates of adjacent cross-sections, analyze the continuous acceleration fluctuation trend, and obtain the stable section feature group. S4: Based on the stable section feature group, compare the coordinates of the cross-section center point with the rotation direction of the attitude angle principal axis, sequentially compare the principal axis orientation with the designed principal axis direction, identify the principal axis orientation trend, and obtain the principal axis orientation parameter set; S5: Based on the set of main axis direction parameters, determine whether the change in main axis direction coincides with the spatial coordinates of the trigger segment identifier set, analyze the distribution characteristics of the overlapping area, correct the amplitude limiting boundary, and obtain the sampling rule adjustment item.

[0006] The present invention is improved in that the trigger segment identifier set includes segment label, association type, and response attribute; the drift determination reference item includes trend identifier, drift period, and response feature; the stable segment feature group includes stable number, feature label, and structure grouping; the principal axis direction parameter set includes spatial vector, offset level, and trend attribute; and the sampling rule adjustment item includes region boundary, sampling frequency, and adjustment range.

[0007] The present invention is improved in that the step of obtaining the trigger segment identifier set is specifically as follows: S111: Based on the construction section of the water conservancy tunnel, analyze the structural partition number and triaxial acceleration measurement results, compare the spatial index of the current measurement point with the measurement point of the previous area, calculate the angle between the triaxial acceleration direction vectors of the two measurement points, determine whether the angle change exceeds the normal fluctuation range, identify the combination of measurement points with direction change characteristics, and obtain the set of acceleration direction change measurement points. S112: Based on the set of acceleration direction change measurement points, analyze the distribution of measurement point pairs in the spatial profile, statistically determine the clustering situation in continuous space, and adjust the inertial navigation acquisition step interval according to the spatial distribution density to obtain the navigation acquisition interval configuration. S113: Based on the navigation acquisition interval configuration, determine the spatial coordinate segment corresponding to the step interval adjustment, analyze the magnitude change of the triaxial acceleration data in the region, identify the profile segment with magnitude change, and obtain the trigger segment identifier set.

[0008] The present invention is improved in that the step of obtaining the drift determination reference item is specifically as follows: S211: Based on the trigger section identifier set, spatial positioning of the construction area during tunnel advancement is performed, the angular velocity time series recorded by the inertial navigation device is obtained, the trend of angular velocity change between consecutive measurement frames is compared, it is determined whether there is a feature of continuous change of direction in the angular velocity change, and the angular velocity sequence of direction change is obtained. S212: Based on the angular velocity sequence of the direction change, combined with the start and end coordinates of the construction area, analyze the attitude angle changes recorded by the navigation device at the spatial boundary, determine the spatial trend of attitude angle changes by comparing the main axis rotation direction of adjacent areas, and obtain the main axis rotation attitude distribution group. S213: Based on the main shaft rotation attitude distribution group and the attitude response information obtained from the on-site inspection, adjust the inertial navigation reference parameters in the area with spatial orientation offset, and obtain drift judgment reference items according to the attitude characteristics of the changed area.

[0009] The present invention is improved in that the step of obtaining the stable segment feature group is specifically as follows: S311: Based on the drift determination reference item, analyze the spatial distribution of the key measurement area, determine the correspondence between the spatial coordinates of the cross section center point and the instantaneous measurement of the triaxial acceleration, calculate the change amplitude and direction consistency of the three-dimensional position of adjacent cross sections, identify cross sections with continuous spatial trajectories, and obtain the cross section continuity identification quantity. S312: Based on the cross-sectional continuity identification quantity, analyze the changing trend of the triaxial acceleration sequence of adjacent cross-sections, determine the consistency of the acceleration curve fluctuations in the sliding region, identify cross-sections with matching trends, and obtain a set of acceleration trend matching identifiers. S313: Based on the acceleration trend matching identifier set, analyze the absolute difference between the triaxial acceleration and spatial position change of the cross section within the same trend region, obtain the same trend stability parameter, identify the cross section with stable same trend, and obtain the stable section feature group.

[0010] The present invention is improved in that the step of obtaining the spindle direction parameter set is specifically as follows: S411: Based on the stable section feature group, analyze the spatial coordinates of the center point of each cross section and the direction of the attitude angle principal axis, compare the spatial angle between the actual principal axis orientation and the designed principal axis direction, calculate the deflection amplitude of each cross section, and obtain the sequence of cross section principal axis deflection angles. S412: Based on the sequence of deflection angles of the main axis of the cross section, determine the change of deflection angle of continuous cross sections, identify spatial segments with the same rotation direction of the main axis, optimize the change path of the main axis orientation between cross sections, and obtain a set of main axis deflection direction trajectories; S413: Based on the set of main shaft deflection direction trajectories, analyze the deflection angle, rotation increment, and spatial direction factor of each cross section, using the following formula: ; Determine the cumulative level of change in the principal axis direction of each spatial segment. The analysis results for each segment are collected to obtain the set of principal axis direction parameters, among which... The number of cross sections in the trajectory set. For the first The principal axis deflection angle of each cross section For the first The rotational increase of the change in the orientation of the principal axis of the cross section. For the first Spatial orientation factor of each cross section.

[0011] The present invention is improved in that the step of obtaining the sampling rule adjustment item is specifically as follows: S511: Based on the main axis direction parameter set, analyze the spatial coordinate information of the trigger section identifier set, determine the overlap state between the tunnel main axis direction change point and the trigger section in space, identify the measurement section that overlaps with the section coordinate when the main axis spatial vector is offset, and obtain the direction overlap area index group. S512: Based on the index group of overlapping directions, the main axis offset trend of each segment is correlated with the preset coordinates of construction sensitive points, the coverage characteristics and distribution density of sensitive segments in the spatial range are analyzed, and a sampled sensitive segment label group is obtained. S513: Based on the label group of the sensitive sampling section, analyze the sampling frequency and sampling boundary settings of the inertial navigation device in the sensitive area, adjust the sampling rules in combination with the changes in the main axis direction parameters, correct the sampling space boundary, and obtain the sampling rule adjustment item.

[0012] The present invention is improved in that the structural partition number refers to dividing the tunnel into multiple partitions according to geological or engineering structural characteristics, and assigning a unique number to each partition; the attitude response refers to the adjustment or change of attitude angle caused by environmental disturbances and external forces to the tunnel structure or construction equipment.

[0013] Compared with the prior art, the advantages and positive effects of the present invention are as follows: In this invention, by continuously acquiring inertial navigation data and dynamically identifying structural response signals during the construction of water conservancy tunnels, a synchronous analysis chain of attitude angle and acceleration sequences is established, forming a data flow mechanism centered on attitude drift monitoring, cross-sectional stability identification, and principal axis direction correction. A differential trigger sampling control method is adopted to optimize the distribution structure of inertial navigation data, ensuring that the acquisition frequency is consistent with structural changes. By identifying offset trends through spatial overlap relationships and generating constraint correction intervals, a closed-loop management of axis alignment, attitude changes, and displacement deviations is formed, ensuring that attitude stability and deviation controllable state are maintained in the closed environment of the tunnel. This promotes the transformation of inertial measurement from intermittent observation to real-time analysis, enhancing the adaptability to dynamic geological environments. Attached Figure Description

[0014] Figure 1 This is a flowchart of the main steps of the present invention; Figure 2 This is a flowchart illustrating the process of obtaining the trigger segment identifier set in this invention; Figure 3 This is a flowchart illustrating the process of obtaining the drift determination reference item in this invention; Figure 4 This is a flowchart of the process for obtaining the stable segment feature group in this invention; Figure 5 This is a flowchart illustrating the process of obtaining the spindle direction parameter set in this invention. Figure 6 This is a flowchart illustrating the process of obtaining the sampling rule adjustment item in this invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0016] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0017] Example Please see Figure 1 This invention provides a technical solution: a method for real-time measurement of axis deviation in hydraulic tunnel construction based on inertial navigation, comprising the following steps: S1: Based on the construction section of the water conservancy tunnel, analyze the collected structural partition number and triaxial acceleration measurement results, select the current measurement point and the previous area measurement point, compare the difference in acceleration direction between the two points, detect the spatial distribution of acceleration changes, adjust the inertial navigation acquisition interval according to the on-site interpretation, and mark the abrupt change area as the key measurement area to obtain the trigger section identifier set; S2: Based on the trigger section identifier set, determine the construction area during the tunnel advancement process, analyze the angular velocity changes collected by the inertial navigation equipment, extract the attitude angle changes at the start and end points of each area, compare the attitude angle trends, monitor the attitude angle change direction of adjacent areas, combine on-site inspection to verify the attitude response, adjust the inertial navigation reference, and obtain drift judgment reference items. S3: Based on the drift determination reference, identify the spatial coordinates of the cross-sectional center point and the instantaneous measurement of triaxial acceleration in the corresponding key measurement area, determine the changes in the spatial coordinates of adjacent cross-sections, analyze the acceleration fluctuation trend of continuous cross-sections, classify the database change records, archive cross-sections that change in the same direction, and obtain the stable section feature group. S4: Based on the stable section feature group, compare the spatial coordinates of the cross section center point with the rotation direction of the attitude angle principal axis, sequentially compare the principal axis orientation with the designed principal axis direction, analyze the changes in the cross section principal axis deflection structure, identify the principal axis orientation trend, record the axis offset characteristics, and obtain the principal axis direction parameter set; S5: Based on the main axis direction parameter set, determine the overlap between the main axis direction change and the spatial coordinates of the trigger section identifier set, analyze the distribution characteristics of the overlapping area, refer to the construction sensitive points, adjust the sampling area rules, correct the amplitude limiting sampling boundary, and obtain the sampling rule adjustment item.

[0018] The trigger segment identifier set includes segment label, association type, and response attribute; the drift judgment reference items include trend identifier, drift period, and response characteristics; the stable segment feature group includes stability number, feature label, and structural grouping; the principal axis direction parameter set includes spatial vector, offset level, and trend attribute; and the sampling rule adjustment items include region boundary, sampling frequency, and adjustment range.

[0019] In S1, the structural partition number refers to dividing the tunnel into multiple partitions based on geological or engineering structural characteristics, with each partition assigned a unique number for location and data collection. Measurement points refer to the specific data collection locations set up at the tunnel construction site for collecting raw data such as inertial navigation and acceleration. Acceleration direction difference refers to the directional changes in the triaxial acceleration data recorded at two measurement points, used to determine the motion state or geological changes. Acceleration change spatial distribution refers to the overall distribution of acceleration changes at different measurement points in space, reflecting the spatial pattern of force or motion response in the tunnel section. Inertial navigation acquisition interval refers to the time interval or step distance when the inertial navigation equipment collects data, affecting data density and response frequency. Abrupt change region refers to the region where parameters in the acceleration and other monitoring data show sudden changes, usually related to changes in geological interfaces or construction conditions.

[0020] In S2, the tunnel advancement process refers to the continuous forward movement of tunneling equipment or construction teams during tunnel construction, encompassing segmentation, advance, etc. Inertial navigation equipment refers to instruments used to measure parameters such as acceleration and angular velocity of objects to calculate position and attitude, such as IMU (Inertial Measurement Unit). Angular velocity change refers to the process of rotational rate change over time recorded by inertial navigation equipment, used to determine attitude and orientation changes. Attitude angle change refers to the change in Euler angles or quaternions formed by the rotation of an object around its principal axes in three-dimensional space, describing the change in the object's orientation state. Attitude angle trend refers to the continuity, directionality, or change pattern of attitude angle changes over a period of time or a distance. Attitude response refers to the adjustment or change of attitude angles caused by environmental disturbances or external forces affecting the tunnel structure or construction equipment. Inertial navigation reference refers to the starting reference parameter set used for inertial navigation calculations, serving as a reference basis for subsequent data calibration and correction.

[0021] In S3, the spatial coordinates of the cross-section center point refer to the specific position coordinates of the center point of a certain cross section (the section perpendicular to the main axis) of the tunnel in three-dimensional space. The instantaneous measurement of triaxial acceleration refers to the acceleration data on the X, Y, and Z axes recorded by the inertial navigation equipment at a certain point in time. The change of cross-section spatial coordinates refers to the change of the three-dimensional coordinates of the cross-section center point continuously collected along the main axis of the tunnel as the spatial position changes, which is used to determine the tunnel orientation or structural state changes. The acceleration fluctuation trend refers to the fluctuation pattern of the acceleration data collected along the continuous cross sections of the tunnel as the space or time changes. The database change record classification refers to the classification, organization, and marking of multiple sets of measurement data collected according to characteristic changes or spatial segmentation, which facilitates subsequent retrieval and analysis.

[0022] In S4, the attitude angle principal axis rotation direction refers to the main direction of rotation reflected by the attitude angle data of the center point of the tunnel cross section, reflecting the spatial orientation characteristics of the section. The design principal axis direction refers to the ideal spatial orientation of the principal axis determined in the design documents or drawings before tunnel construction. The principal axis deflection structural change refers to the spatial deflection, bending or turning phenomenon that occurs between the actual measured principal axis orientation and the design principal axis orientation. The principal axis orientation trend refers to the trend of the change of the principal axis direction in continuous spatial position in the measurement data, including gradual, offset, rotation, etc. The axis offset characteristic refers to the measurement characteristics that reflect the deviation of the actual spatial path of the principal axis from the design path, which is often used to evaluate construction accuracy or structural deformation.

[0023] In S5, overlapping area distribution characteristics refer to the spatial overlap distribution of two or more spatial datasets (such as the main axis direction change and trigger section identifier set). Construction sensitive points refer to specific locations within the tunnel that are highly sensitive to structural safety, monitoring accuracy, or construction control. These are generally determined by geological, structural, or design requirements. Sampling area rules refer to the operational procedures set for spatial division, sampling density, and sampling range for inertial navigation and acceleration data acquisition. Amplitude limiting sampling boundaries refer to data sampling boundary restrictions set to prevent abnormal data from affecting the overall judgment. These are usually ranges of values ​​in a spatial, physical, or statistical sense.

[0024] Please see Figure 2 The specific steps for obtaining the trigger segment identifier set are as follows: S111: Based on the construction section of the water conservancy tunnel, analyze the structural partition number and triaxial acceleration measurement results, compare the spatial index of the current measurement point with the measurement point of the previous area, calculate the angle between the triaxial acceleration direction vectors of the two measurement points, determine whether the angle change exceeds the normal fluctuation range, identify the combination of measurement points with direction change characteristics, and obtain the set of acceleration direction change measurement points. Extract the corresponding structural partition number and call the triaxial acceleration measurement results of the current measurement point and the previous measurement point. Match them one by one in the tunnel advancement direction according to the coordinate index. Normalize the triaxial acceleration direction values ​​of the two measurement points to obtain comparable direction vectors. Multiply the components of the two vectors one by one and sum them to obtain the change value of the direction angle. By setting an angle threshold within the normal fluctuation range, judge the angle value of each pair of measurement points. When the measured direction change angle is greater than the threshold, mark the pair of measurement points as a direction change combination. Then, number and archive the measurement point combination in the construction monitoring. At the same time, associate it with the structural section number information and its three-dimensional spatial coordinates to form a direction change record list. In the examples recorded in the field data, if the acceleration direction of adjacent measurement points changes significantly in the longitudinal direction, it is automatically judged as a direction change feature measurement point. If more than three consecutive measurement points with similar direction changes are detected in the field between the Z4 and Z5 sections, the points are classified into the same section index to ensure the formation of a complete set of acceleration direction change measurement points.

[0025] S112: Based on the set of measurement points for changes in acceleration direction, analyze the distribution of measurement point pairs in the spatial profile, statistically determine the clustering situation in continuous space, and adjust the inertial navigation acquisition step interval according to the spatial distribution density to obtain the navigation acquisition interval configuration. The distribution of measuring points in the tunnel spatial profile is analyzed, and the spatial coordinates of each measuring point are mapped onto the tunnel cross-section. The spatial distance between adjacent measuring points is calculated and compared with a preset spatial density reference distance. When the distance between multiple consecutive measuring points is lower than the reference value, the area is identified as an acceleration change cluster. The number of measuring points in the cluster is then counted. When the number exceeds a set threshold, the area is judged to have a high concentration of spatial changes and is marked as a key monitoring section. The step interval of inertial navigation acquisition is adjusted according to the degree of clustering. If the number of measuring points in the cluster is dense, the step interval is shortened to half of the original value. In more dispersed areas, the original interval remains unchanged. For example, when five directional change points are detected in a 10-meter interval and the distance between them is less than 3 meters, the step interval of that section is automatically adjusted from 2 meters to 1 meter, and a corresponding navigation acquisition interval configuration table is generated.

[0026] S113: Based on the navigation acquisition interval configuration, determine the spatial coordinate segment corresponding to the step interval adjustment, analyze the magnitude change of the triaxial acceleration data in the region, identify the profile segment with magnitude change, and obtain the trigger segment identifier set; Based on the generated navigation acquisition interval configuration, the corresponding spatial coordinate segments are re-divided. The triaxial acceleration data in each segment are retrieved one by one, and its modulus value sequence is extracted and calculated. The modulus change amplitude between adjacent measuring points is compared with the set change recognition range. When the modulus difference of consecutive measuring points exceeds the set range, the section is marked as an area with significant change. Then, the start and end coordinates of the area, the measuring point number, and the structural partition number are associated to generate a segment index with acceleration mutation attributes. The index is integrated into a trigger segment identifier set and stored in the inertial navigation control unit for subsequent retrieval and annotation in the tunnel construction monitoring system.

[0027] Please see Figure 3 The specific steps for obtaining the drift determination reference are as follows: S211: Based on the trigger section identifier set, spatial positioning of the construction area during tunnel advancement is performed, the angular velocity time series recorded by the inertial navigation equipment is obtained, the trend of angular velocity change between consecutive measurement frames is compared, it is determined whether there is a feature of continuous change of direction in the angular velocity change, and the angular velocity sequence of direction change is obtained. Based on the segment number, measuring point number, and spatial coordinate information in the trigger segment identifier set, the construction area during tunnel advancement is located one by one. For each segment, the raw angular velocity records collected by the inertial navigation equipment are retrieved, and the corresponding timestamps and angular velocity values ​​in three directions are extracted to form a time series. In this time series, adjacent frames are paired according to time order, and the angular velocity components in the three directions are extracted respectively. The angular velocity difference between each frame and the next frame is calculated to obtain the angular velocity change sequence. Then, the directional consistency of the changes in this sequence is compared group by group, and the positive and negative directions of adjacent changes are marked to determine whether there is a consistent trend of change in direction among multiple consecutive frames. If there are five or more consecutive frames with the same angular velocity change direction, it is marked. For sections with continuously changing direction, the comparison and judgment process uses the consistency of the signs of five adjacent items in the angular velocity change sequence as the judgment criterion. The judgment threshold is set to a minimum continuous frame count of 5 frames. This value comes from the fact that when the equipment sampling frequency is 10Hz, 5 consecutive frames represent 0.5 seconds of continuous action, which can effectively cover the normal deflection or attitude response cycle of the shield tunneling equipment. During tunnel advancement, if in section Z7, starting from measuring point P85, the angular velocity sequence collected by the equipment has 6 consecutive frames with positive change values ​​in the Y-axis direction, and the change amplitude is higher than the set minimum change judgment threshold of 0.02 rad / s, then this section is judged to have a continuous change in direction feature. All angular velocity data segments that meet this condition are extracted, summarized, and numbered to form a directional change angular velocity sequence.

[0028] S212: Based on the angular velocity sequence of direction change, combined with the start and end coordinates of the construction area, analyze the attitude angle changes recorded by the navigation equipment at the spatial boundary, determine the spatial trend of attitude angle changes by comparing the main axis rotation direction of adjacent areas, and obtain the main axis rotation attitude distribution group. Based on the obtained angular velocity sequence of directional changes, the spatial boundary of the construction area is located, and the starting and ending spatial coordinates of each angular velocity change segment are extracted. Combined with the attitude angle data recorded by the navigation equipment in space, the attitude angle values ​​of the three principal axes at the corresponding start and end positions are extracted. An attitude change vector is constructed in the spatial axis system. The directional distribution of this attitude change vector is compared with the attitude vectors of adjacent segments. The difference between the principal axis rotation directions of the preceding and following segments is processed, and the increasing or decreasing trend of the directional rotation in the spatial axis is statistically analyzed to determine whether there is a trend of continuous rotation transitioning from the previous segment to the following segment. A threshold of 5 for the rotation direction difference is set. The degree is used as a criterion for judging whether the rotation direction of adjacent segments has changed. When the difference between the rotation directions of the main shaft of two segments in a certain axis exceeds 5 degrees and the direction of change is consistent, it is considered that there is a continuous main shaft attitude rotation trend. Then, the segments with consistent directional changes are grouped together and marked as a group of continuous main shaft rotation attitude data. At the same time, its distribution range and rotation axis are recorded on the cross-sectional diagram, thus constructing a main shaft rotation attitude distribution group. For example, in the Z8 to Z9 segment, the attitude angle changes continuously from 15 degrees to 22 degrees in the X-axis direction, and the change value between each segment is higher than 5 degrees, with the direction deflecting to the right. Then, this segment is classified as the main shaft right deflection rotation trend group.

[0029] S213: Based on the spindle rotation attitude distribution group and combined with the attitude response information obtained from on-site inspection, adjust the inertial navigation reference parameters in areas with spatial orientation offset, and obtain drift judgment reference items based on the attitude characteristics of the changing areas. At the construction site, attitude response information obtained during manual inspections is used to verify the actual structural response of each spatial segment. The measured attitude changes are compared with parameters such as the position and orientation of on-site equipment, the eccentricity of the tunnel lining, and the angle of the advancing shield. The spatial deflection angles appearing in the measured data are paired and analyzed with the attitude angle changes in the navigation data to confirm whether there is an orientation shift trend. In the segment with the shift, the current reference attitude parameters of the inertial navigation system are extracted, and the difference between them and the standard alignment attitude is calculated. For the axis with continuous shift, the reference angle offset is adjusted to correct the starting point of subsequent data calculation. In actual engineering, for example, in the Z10 segment, manual inspection found that the shield head deviated from the design axis direction by about 8 degrees, while the attitude angle offset recorded by the inertial navigation equipment was only 4 degrees. In this segment, the inertial navigation reference parameters are offset compensation according to the difference between 4 degrees and 8 degrees, the initial angle parameters of the current attitude angle are corrected, and this adjustment is recorded as the basis for drift judgment. This segment is set as a deflection monitoring area, and drift judgment reference items are output.

[0030] Please see Figure 4 The specific steps for obtaining the feature set of the stable segment are as follows: S311: Based on the drift determination reference, analyze the spatial distribution of key measurement areas, determine the correspondence between the spatial coordinates of the cross section center point and the instantaneous measurement of triaxial acceleration, calculate the change amplitude and direction consistency of the three-dimensional position of adjacent cross sections, identify cross sections with continuous spatial trajectories, and obtain the cross section continuity identification quantity. The spatial distribution of key measurement areas is extracted. The spatial coordinates of the center points of cross-sections within each key measurement area, along with the corresponding instantaneous triaxial acceleration data recorded at the corresponding time points, are retrieved. First, the center point positions of each cross-section are sorted according to the tunnel's main axis direction, forming a continuous cross-section spatial index sequence. Then, the spatial position difference between the center points of adjacent cross-sections is calculated using three-dimensional coordinates, determining the change amplitude in the X, Y, and Z directions. A coordinate change identification threshold of 0.2 meters is set. When the center point displacement change in a certain direction exceeds this threshold, it is marked as a structural change point. Subsequently, the direction of positional change between continuous cross-sections is compared item by item, marking the displacement direction of the current cross-section center point relative to the previous segment as forward, left, or right. Consistency judgment is made with the change direction of the previous section. If five consecutive cross sections show the same change direction, the spatial trajectory direction of this section is judged to be consistent, and all cross sections in this section are marked as continuous spatial trajectory cross sections. The judgment results are further statistically analyzed. If five adjacent sections pass the direction consistency judgment, the average spatial change of this group of cross sections is calculated and compared with the overall drift trend direction. In actual data, such as the six cross sections arranged between station DK12+480 and DK12+500, their X-direction displacement change values ​​are 0.18, 0.21, 0.23, 0.22, 0.24 and 0.20 meters, respectively. All of them are higher than the set threshold and the direction is consistent. They are judged to be a group of continuous spatial trajectory cross sections, and the cross section continuity identification value is obtained.

[0031] S312: Based on the cross-sectional continuity identification quantity, analyze the changing trend of the triaxial acceleration sequence of adjacent cross-sections, determine the consistency of the acceleration curve fluctuations in the sliding region, identify cross-sections with consistent trends, and obtain the acceleration trend consistent identifier set. Acceleration time series in the X, Y, and Z directions are extracted for each cross-section, constructing a triaxial acceleration change sequence group indexed by the cross-section number. Then, within this sequence group, a sliding window is applied to the acceleration curve in each direction, with a window width of 5 cross-sections. The mean and standard deviation of acceleration in each direction within the window are extracted. The difference between the current window and the previous window is calculated, and it is determined whether the fluctuations of the acceleration change curves tend to be consistent within a set range. The consistency threshold is set as follows: the difference in the mean fluctuation in the same direction does not exceed 0.3 m / s², and the difference in the standard deviation does not exceed [a certain threshold value]. If the above two conditions are met, the acceleration fluctuation of the cross section within the window is determined to be consistent. In this way, all windows are judged by sliding judgment on the entire cross section. Cross sections that meet the consistency criteria are marked as trend matching points, and a list of trend matching cross section numbers is generated. For example, in the cross sections D21 to D26 in the Z6 section, the average value of the Y-axis acceleration changes within 0.28 m / s² and the standard deviation is 0.12 m / s² during sliding judgment. Moreover, the direction of change is consistent among all windows. They are judged as acceleration trend matching areas, and an acceleration trend matching identifier set is obtained.

[0032] S313: Based on the acceleration trend matching identifier set, analyze the absolute difference between the triaxial acceleration and spatial position changes in the cross-section within the same trend region, using the formula: ; Obtain the stability parameters of the same trend By identifying cross-sections with stable trends in the same direction, a characteristic group of stable sections is obtained, among which... This indicates the number of cross sections within the trend region. Indicates the first The mean of the triaxial accelerations of each cross section, Indicates the first The average value of the spatial position change of each cross section relative to the previous cross section; The unidirectional trend stability parameter is a quantifiable parameter used to characterize the consistency and coherence between the acceleration response trend and spatial position change trend of a continuous cross-section sequence along the principal spatial axis during tunnel construction. Specifically, this parameter reflects the absolute difference between the mean triaxial acceleration of each tunnel cross-section and the mean spatial position change of adjacent cross-sections within a certain region. If the parameter value is small, it indicates that the spatial position change and acceleration response change of the cross-section show a high degree of consistency within the trend region, i.e., unidirectional trend stability. If the parameter value is large, it indicates that there is a significant inconsistency or fluctuation between the spatial and acceleration change trends, indicating trend instability. The triaxial acceleration measurement data and spatial position change data of the cross sections were analyzed sequentially. First, the instantaneous triaxial acceleration measurement results of cross sections 2, 3, 4, and 5 were obtained, where the acceleration of cross section 2 was... Cross section 3 is Cross section 4 is Cross section 5 is Calculate the acceleration modulus of each cross section to obtain the original data: Cross section 2 is Cross section 3 is Cross section 4 is Cross section 5 is Simultaneously, the corresponding spatial position change distance is obtained, in sequence for cross-section 2. Cross section 3 is Cross section 4 is Cross section 5 is Using the minimum-maximum normalization method, the acceleration and position difference are unified to a certain value. The normalized acceleration modulus results for the intervals are as follows: Cross section 2 is Cross section 3 is Cross section 4 is Cross section 5 is The normalized spatial location differences are as follows: Cross-section 2 is... Cross section 3 is Cross section 4 is Cross section 5 is Substitute the normalized values ​​into the formula, where... This indicates the number of cross-sections within the trend region, which can be calculated item by item: Cross Section 2: ; Cross Section 3: ; Cross Section 4: ; Cross Section 5: ; Adding the above four items together and taking the average, we get: ; Based on engineering experience and historical data statistics, the preset range for the same-trend stability parameter is set as follows: when When the trend is highly consistent, the segment is judged to be a "segment with a high degree of consistency". The changes in cross-sectional acceleration and spatial structure within this segment have good consistency and can be directly classified into the stable segment characteristic group. when When the segment is judged to be "moderate deviation from the trend", such segments have a certain degree of inconsistency between acceleration and structural response on some cross sections. Further detailed judgment is required, and local low-difference cross sections can be extracted to form a candidate group of stable segments. when When the acceleration response and spatial trajectory change are significantly deviated, the region is considered a "significant trend separation segment". This region cannot be regarded as a stable trend region and must be completely eliminated.

[0033] Current calculation results fall into The interval belongs to the "moderate deviation segment of the trend", indicating that although the current cross-sectional sequence has a certain continuity, the trend consistency is insufficient and it cannot be classified into the stable segment feature group as a whole. It can only further filter the cross-sectional units with small local fluctuation differences to construct the initial subset or reference frame of the stable segment feature group, which can be used as the spatial reference input in the subsequent structural direction parameter extraction process.

[0034] Please see Figure 5 The specific steps for obtaining the spindle direction parameter set are as follows: S411: Based on the stable section feature group, analyze the spatial coordinates of the center point of each cross section and the direction of the attitude angle principal axis, compare the spatial angle between the actual principal axis orientation and the design principal axis direction, calculate the deflection amplitude of each cross section, and obtain the sequence of cross section principal axis deflection angles. The spatial coordinates of the center point of each cross section are extracted to construct a three-dimensional position vector. Correspondingly, the attitude angle principal axis direction vector recorded at the acquisition time of each cross section is retrieved from the inertial navigation equipment. The spatial angle between this direction vector and the principal axis direction vector marked on the design drawings is calculated. By comparing the projections of the two vectors on the three spatial axes, the cosine value is solved and converted into angle data to obtain the angle between the actual principal axis direction and the design principal axis direction. This angle data is recorded as a deflection amplitude index. According to the tunnel construction design specifications, a judgment level is set for the deflection angle, defining the angle less than 2 degrees as the normal range, 2 to 5 degrees as the slight deflection range, and greater than 5 degrees as the deflection range. The section with significant deflection is defined by the allowable deviation range of the centerline control in the shield tunnel construction monitoring standard. Based on an example of a tunnel section in an actual project, the spatial coordinates of the center point of cross section D35 are (100.2, 23.8, -3.5), and the measured vector of its principal axis direction is (0.98, 0.02, 0.17). The designed principal axis direction is (1.00, 0.00, 0.00). The calculated angle is 5.5 degrees, which is determined to be a significant deflection section. This result is recorded as the principal axis deflection angle of this cross section. The above process is repeated to process the cross section data in all stable sections sequentially, generating a complete sequence of principal axis deflection angles for each cross section.

[0035] S412: Based on the sequence of principal axis deflection angles of cross sections, determine the changes in deflection angles of continuous cross sections, identify spatial segments with the same principal axis rotation direction, optimize the path of change in principal axis orientation between cross sections, and obtain a set of principal axis deflection direction trajectories. Following the order of cross-sections, the trend of deflection angle changes between adjacent cross-sections is analyzed item by item. The deflection angle of the current cross-section is compared with the deflection angle of the previous cross-section, and the difference between the two is extracted. The sign of the difference is used to determine whether the direction of deflection angle change is consistent. When the deflection angles of multiple consecutive cross-sections are all increasing or decreasing and have the same direction sign, they are defined as a spatial segment with the same direction of rotation of the main axis. In actual operation, the minimum threshold for the number of consecutive segments is set to 5 cross-sections. If 5 or more consecutive cross-sections have the same direction of deflection angle, the segment is determined to be in direction one. For example, if the deflection angles between D40 and D45 are 2.1, 2.7, 3.3, 4.1, 5.2, and 6.0 degrees respectively, and the direction is consistent and increasing in a positive direction, it meets the judgment condition. Record this segment as a right-hand deflection segment. Then, interpolate and fit the principal axis direction vectors of all cross sections within this segment, smooth the principal axis direction change path item by item, eliminate the influence of small fluctuations, and extract the continuous path with the smallest change as a representative trajectory. Number the trajectory segments of each region with consistent direction that meets the condition, and summarize them to form a set of principal axis deflection direction trajectories.

[0036] S413: Based on the set of principal axis deflection direction trajectories, analyze the deflection angle, rotation increment, and spatial direction factor of each cross section using the following formula: ; Determine the cumulative level of change in the principal axis direction of each spatial segment. The analysis results for each segment are collected to obtain the set of principal axis direction parameters, among which... The number of cross sections in the trajectory set. For the first The principal axis deflection angle of each cross section For the first The rotational increase of the change in the orientation of the principal axis of the cross section. For the first The spatial orientation factor of each cross section is formed by the ratio of the magnitude of the orientation vector of that cross section to the reference length, and is dimensionless. The cumulative change level of the main axis orientation refers to the "total quantitative representation" of the main axis orientation offset and rotation increase within a specified section. It integrates the spatial main axis deviation phenomena of all cross-sections and is used to measure the overall orientation change of the tunnel main axis within that section. The larger the value, the more significant the overall spatial offset and orientation change of the main axis within that section. Analyze the principal axis deflection angles corresponding to each cross section. Rotational amplification With spatial direction factor During tunnel excavation, the deflection angle The rotational increase was calculated by comparing the angle between the measured principal axis direction and the designed principal axis direction. The spatial orientation factor is obtained from the difference in attitude calculations between two consecutive cross-sections. The dimensionless parameter is formed by the ratio of the three-dimensional spatial position modulus of the cross-section center point to the reference length. To unify the participation of various physical quantities in multiplication and division calculations, an extremum normalization method is used to process angle-type data. The original values ​​of the three sets of cross-section parameters are given as follows: , , , , , ; Spatial modulus is , , ; The corresponding values ​​after normalization are respectively , , , , , , , , Substituting it into the formula, we get: The first item is: ; The second item is: ; The third item is: ; Summing yields: ; Will The distribution range is divided into the following three segments: when When the spindle direction is basically stable and there is no continuous deflection trend between the spindle attitude and the design direction, it is called the "stable segment". when When the spindle exhibits a finite-amplitude rotational response in space and does not show any structural offset, it is classified as a "slightly changing segment". when When the axis direction has formed a continuous offset structure, its attitude and the design direction have a trend of change characteristics, which is called "significant offset segment".

[0037] The calculation obtained in this embodiment Located in the last category, it indicates that the main axis direction of the trajectory segment has undergone a cumulative and continuous directional shift within the stable section. It belongs to a region with strong spatial attitude response and needs to be identified as a high-variability path segment and written into the main axis direction parameter set for use in downstream steps such as spatial coincidence judgment, sampling boundary adjustment, and structural behavior response annotation.

[0038] Please see Figure 6 The specific steps for obtaining the sampling rule adjustment items are as follows: S511: Based on the main axis direction parameter set, analyze the spatial coordinate information of the trigger section identifier set, determine the overlap state between the tunnel main axis direction change point and the trigger section in space, identify the measurement section that overlaps with the section coordinate when the main axis spatial vector is offset, and obtain the direction overlap area index group. All points where the main axis direction changes are extracted, and a coordinate set of these points is constructed. Simultaneously, the corresponding segment coordinate information and segment labels are retrieved from the trigger segment identifier set. The spatial positions of the two coordinate datasets are compared point by point. The three-dimensional spatial coordinates of the points where the main axis direction changes are changed are compared with the start and end coordinate ranges of the trigger segment to determine if they fall within that segment. The comparison method involves checking if the X, Y, and Z coordinates of the points where the main axis direction changes simultaneously fall between the minimum and maximum boundary values ​​of the trigger segment. When three or more consecutive points where the main axis direction changes coincide with the coordinate range of the trigger segment, a spatial overlap is established. The minimum number of overlap points is set to 3, a value derived from the minimum continuous measurement distance of the navigation device at a 2-meter interval. Regarding the number of points, in actual engineering, for example, if the set of main axis direction parameters contains measuring point numbers M24, M25, and M26 at positions (101.0, 24.3, -3.8), (102.8, 24.6, -3.7), and (104.4, 25.0, -3.5) respectively, and the coordinate range of the trigger segment T8 is set as X-axis 101 to 105, Y-axis 24 to 26, and Z-axis -4 to -3, then all three points are within the spatial boundary of T8, and it is determined that the spatial overlap is established. The T8 segment is associated with the set of main axis offset points, and the change in main axis direction within the segment is recorded and responded synchronously with the trigger condition. All segment numbers and measuring point numbers that meet the overlap condition are merged to form a direction overlap area index group.

[0039] S512: Based on the index group of overlapping directions, the main axis offset trend of each section is matched with the preset coordinates of construction sensitive points. The coverage characteristics and distribution density of sensitive sections in the spatial range are analyzed to obtain the label group of sampled sensitive sections. Based on the segment numbers and measuring point coordinates recorded in the aforementioned direction coincidence area index group, the main axis offset trend within each segment is extracted sequentially. The offset direction is spatially mapped to the coordinates of the pre-set construction sensitive points. The coordinates of the sensitive points are input according to the design drawings and stored in the sensitive point index table. It is determined whether each direction coincidence segment is within the control radius set for the sensitive points. The spatial sensitivity judgment radius is set to 3 meters, which is based on the allowable control accuracy standard during construction. When the spatial straight-line distance from the direction change point to the sensitive point is less than 3 meters, the impact of that segment on the sensitive point is recorded. Then, the number and coverage of sensitive points involved in all triggering segments are counted, and the sensitive points are numbered. The corresponding segments are categorized. When a sensitive point is covered by multiple trigger segments and the trend of change in the main axis direction is consistent, it is judged as high-density coverage. The density level is divided as follows: 1 coverage time is defined as low density, 2-3 times is medium density, and more than 3 times is high density. In actual engineering, for example, if the sensitive point E3 is set at (102.0, 24.0, -3.6), if there are measuring points less than 3 meters away from E3 in the three segments T8, T9, and T10 of the index group, and their offset direction is all rotated to the right, then E3 is marked as a high-density influence area, and the corresponding segment is assigned a sampling sensitive label, generating a sampling sensitive segment label group covering all sensitive point locations.

[0040] S513: Based on the label group of the sensitive sampling section, analyze the sampling frequency and sampling boundary settings of the inertial navigation device in the sensitive area, adjust the sampling rules in combination with the changes in the main axis direction parameters, correct the sampling space boundary, and obtain the sampling rule adjustment item; The sampling frequency and spatial sampling boundary settings recorded by the inertial navigation device are extracted sequentially. The sampling frequency is compared with the standard frequency parameter table to determine whether the current frequency is lower than the recommended sampling frequency for sensitive areas. The recommended minimum sampling frequency for sensitive areas is set to 5Hz. When the actual frequency is lower than this value, it is marked as insufficient sampling frequency. Then, the spatial sampling boundary values ​​of the segment are analyzed. The spatial boundary distance of each measuring point is mapped to the change amplitude of the main axis direction to determine whether the boundary expansion matches the direction offset. When the direction offset amplitude exceeds the set threshold of 5 degrees and the boundary sampling width is less than 1 meter, the sampling boundary is adjusted to 1.5 times the current value to ensure that the spatial coverage matches the offset change area. For example, in the sampling sensitive segment T9, the recorded sampling frequency is 4Hz, the main axis offset angle is 6.2 degrees, and the original boundary width is 0.8 meters. It is determined that the sampling rule needs to be corrected. The frequency is adjusted to 6Hz, and the boundary width is expanded to 1.2 meters. The adjustment results are recorded as parameters, and the sampling rule adjustment item is output.

[0041] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for real-time measurement of axis deviation in hydraulic tunnel construction based on inertial navigation, characterized in that, Includes the following steps: S1: Based on the construction section of the water conservancy tunnel, analyze the structural partition number and triaxial acceleration results, compare the difference in acceleration direction between the current and previous measurement points, determine the spatial distribution of acceleration changes, adjust the acquisition interval, and obtain the trigger section identifier set; S2: Based on the trigger segment identifier set, analyze the angular velocity changes collected by the inertial navigation device, monitor the attitude angle change trend, verify the attitude response, adjust the navigation reference, and obtain drift judgment reference items; S3: Based on the drift determination reference, identify the spatial coordinates of the cross-sectional center point of the key measurement area and the instantaneous measurement of the three-axis acceleration, determine the changes in the coordinates of adjacent cross-sections, analyze the continuous acceleration fluctuation trend, and obtain the stable section feature group. S4: Based on the stable section feature group, compare the coordinates of the cross-section center point with the rotation direction of the attitude angle principal axis, sequentially compare the principal axis orientation with the designed principal axis direction, identify the principal axis orientation trend, and obtain the principal axis orientation parameter set; S5: Based on the set of main axis direction parameters, determine whether the change in main axis direction coincides with the spatial coordinates of the trigger segment identifier set, analyze the distribution characteristics of the overlapping area, correct the amplitude limiting boundary, and obtain the sampling rule adjustment item.

2. The method for real-time measurement of axis deviation in hydraulic tunnel construction based on inertial navigation according to claim 1, characterized in that, The triggering segment identifier set includes segment labels, association types, and response attributes; the drift determination reference items include trend identifiers, drift cycles, and response characteristics; the stable segment feature group includes stability numbers, feature labels, and structural groupings; the principal axis direction parameter set includes spatial vectors, offset levels, and trend attributes; and the sampling rule adjustment items include region boundaries, sampling frequency, and adjustment range.

3. The method for real-time measurement of axis deviation in hydraulic tunnel construction based on inertial navigation according to claim 1, characterized in that, The specific steps for obtaining the trigger segment identifier set are as follows: S111: Based on the construction section of the water conservancy tunnel, analyze the structural partition number and triaxial acceleration measurement results, compare the spatial index of the current measurement point with the measurement point of the previous area, calculate the angle between the triaxial acceleration direction vectors of the two measurement points, determine whether the angle change exceeds the normal fluctuation range, identify the combination of measurement points with direction change characteristics, and obtain the set of acceleration direction change measurement points. S112: Based on the set of acceleration direction change measurement points, analyze the distribution of measurement point pairs in the spatial profile, statistically determine the clustering situation in continuous space, and adjust the inertial navigation acquisition step interval according to the spatial distribution density to obtain the navigation acquisition interval configuration. S113: Based on the navigation acquisition interval configuration, determine the spatial coordinate segment corresponding to the step interval adjustment, analyze the magnitude change of the triaxial acceleration data in the region, identify the profile segment with magnitude change, and obtain the trigger segment identifier set.

4. The method for real-time measurement of axis deviation in hydraulic tunnel construction based on inertial navigation according to claim 1, characterized in that, The specific steps for obtaining the drift determination reference item are as follows: S211: Based on the trigger section identifier set, spatial positioning of the construction area during tunnel advancement is performed, the angular velocity time series recorded by the inertial navigation device is obtained, the trend of angular velocity change between consecutive measurement frames is compared, it is determined whether there is a feature of continuous change of direction in the angular velocity change, and the angular velocity sequence of direction change is obtained. S212: Based on the angular velocity sequence of the direction change, combined with the start and end coordinates of the construction area, analyze the attitude angle changes recorded by the navigation device at the spatial boundary, determine the spatial trend of attitude angle changes by comparing the main axis rotation direction of adjacent areas, and obtain the main axis rotation attitude distribution group. S213: Based on the main shaft rotation attitude distribution group and the attitude response information obtained from the on-site inspection, adjust the inertial navigation reference parameters in the area with spatial orientation offset, and obtain drift judgment reference items according to the attitude characteristics of the changed area.

5. The method for real-time measurement of axis deviation in hydraulic tunnel construction based on inertial navigation according to claim 1, characterized in that, The specific steps for obtaining the stable segment feature group are as follows: S311: Based on the drift determination reference item, analyze the spatial distribution of the key measurement area, determine the correspondence between the spatial coordinates of the cross section center point and the instantaneous measurement of the triaxial acceleration, calculate the change amplitude and direction consistency of the three-dimensional position of adjacent cross sections, identify cross sections with continuous spatial trajectories, and obtain the cross section continuity identification quantity. S312: Based on the cross-sectional continuity identification quantity, analyze the changing trend of the triaxial acceleration sequence of adjacent cross-sections, determine the consistency of the acceleration curve fluctuations in the sliding region, identify cross-sections with matching trends, and obtain a set of acceleration trend matching identifiers. S313: Based on the acceleration trend matching identifier set, analyze the absolute difference between the triaxial acceleration and spatial position change of the cross section within the same trend region, obtain the same trend stability parameter, identify the cross section with stable same trend, and obtain the stable section feature group.

6. The method for real-time measurement of axis deviation in hydraulic tunnel construction based on inertial navigation according to claim 1, characterized in that, The specific steps for obtaining the spindle direction parameter set are as follows: S411: Based on the stable section feature group, analyze the spatial coordinates of the center point of each cross section and the direction of the attitude angle principal axis, compare the spatial angle between the actual principal axis orientation and the designed principal axis direction, calculate the deflection amplitude of each cross section, and obtain the sequence of cross section principal axis deflection angles. S412: Based on the sequence of deflection angles of the main axis of the cross section, determine the change of deflection angle of continuous cross sections, identify spatial segments with the same rotation direction of the main axis, optimize the change path of the main axis orientation between cross sections, and obtain a set of main axis deflection direction trajectories; S413: Based on the set of main shaft deflection direction trajectories, analyze the deflection angle, rotation increment, and spatial direction factor of each cross section, using the following formula: ； Determine the cumulative level of change in the principal axis direction of each spatial segment. The analysis results for each segment are collected to obtain the set of principal axis direction parameters, among which... The number of cross sections in the trajectory set. For the first The principal axis deflection angle of each cross section For the first The rotational increase of the change in the orientation of the principal axis of the cross section. For the first Spatial orientation factor of each cross section.

7. The method for real-time measurement of axis deviation in hydraulic tunnel construction based on inertial navigation according to claim 1, characterized in that, The specific steps for obtaining the sampling rule adjustment item are as follows: S511: Based on the main axis direction parameter set, analyze the spatial coordinate information of the trigger section identifier set, determine the overlap state between the tunnel main axis direction change point and the trigger section in space, identify the measurement section that overlaps with the section coordinate when the main axis spatial vector is offset, and obtain the direction overlap area index group. S512: Based on the index group of overlapping directions, the main axis offset trend of each segment is correlated with the preset coordinates of construction sensitive points, the coverage characteristics and distribution density of sensitive segments in the spatial range are analyzed, and a sampled sensitive segment label group is obtained. S513: Based on the label group of the sensitive sampling section, analyze the sampling frequency and sampling boundary settings of the inertial navigation device in the sensitive area, adjust the sampling rules in combination with the changes in the main axis direction parameters, correct the sampling space boundary, and obtain the sampling rule adjustment item.

8. The method for real-time measurement of axis deviation in hydraulic tunnel construction based on inertial navigation according to claim 1, characterized in that, The structural partition number refers to dividing the tunnel into multiple partitions based on geological or engineering structural characteristics, with each partition assigned a unique number. The attitude response refers to the adjustment or change of attitude angle caused by environmental disturbances or external forces to the tunnel structure or construction equipment.

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