A method and system for monitoring the settlement of the vault of a metro tunnel in operation

Abstract

The application discloses a kind of operation period subway tunnel vault settlement laser monitoring method and system, it is related to subway tunnel structure deformation monitoring field.The method determines bottom reference measuring point in tunnel monitoring section, obtains initial distance data of vault target area, extracts vault natural surface local feature and establishes reference surface feature template;Subsequent monitoring obtains current attitude state and reference area measurement information, determines measurement reference correction, and the current local surface feature is matched with reference surface feature template, determines corresponding current natural measurement position;Current measurement distance is obtained, vertical displacement of vault is determined after measurement reference correction, and according to the vertical displacement of continuous multiple monitoring time periods, it determines cumulative settlement and settlement change trend.The application does not need to set artificial target or contact type measuring point on vault, can improve the consistency of measurement position of different monitoring time periods and the reliability of settlement monitoring result, and realizes abnormal identification and settlement early warning.

Description

Technical Field

[0001] This invention relates to the field of subway tunnel structural deformation monitoring, and in particular to a laser monitoring method and system for the settlement of the arch of a subway tunnel during operation. Background Technology

[0002] During long-term operation, subway tunnels are affected by factors such as changes in surrounding rock stress, groundwater action, long-term dynamic loads from trains, construction work in surrounding areas, and changes in the performance of structural materials, which can cause varying degrees of deformation in the tunnel lining structure. Vertical displacement of the tunnel crown and cumulative settlement are important monitoring parameters for evaluating the stability of the tunnel structure. Periodic monitoring of the crown settlement of operating tunnels helps to promptly grasp the trend of tunnel structural deformation and identify potential anomalies. Current monitoring of operating tunnels typically requires full utilization of train downtime for on-site operations. However, the limited downtime during these periods places high demands on the efficiency of monitoring equipment deployment, the accuracy of repeat measurements, and the degree of automation. Existing technologies using manual measurement methods such as levels and total stations often require extensive on-site operations, and the measurement efficiency and consistency between different measurements are easily affected by human factors.

[0003] Currently, crown displacement can also be monitored using contact displacement probes. This involves determining the monitoring location on-site, then using support rods or telescopic rods to bring the displacement probe into contact with the crown surface. Displacement sensors at each measuring point are connected to data acquisition equipment or a computer to obtain the displacement changes at that point. This method can directly obtain crown displacement information, but during multiple periodic monitoring sessions, it is necessary to ensure good consistency in the probe's installation position, support posture, and contact position with the crown. Factors such as equipment relocation, support rod posture, probe contact position, and contact state changes can introduce additional measurement errors between different monitoring periods. Furthermore, when multiple monitoring sections are set up within the tunnel, the workload of on-site equipment installation, adjustment, and cable connections will also increase.

[0004] To reduce the impact of on-site deployment associated with contact monitoring, laser ranging can be used for non-contact distance measurement of the tunnel arch from the tunnel bottom. A reference measuring point is set up at the tunnel bottom, and the laser ranging unit emits a laser beam towards the arch, directly utilizing the natural surface of the arch's concrete for distance measurement, thus eliminating the need for a dedicated target on the arch. However, without a fixed target, the laser illumination position may shift slightly between different monitoring periods due to minor changes in equipment installation location, measurement direction, and orientation. Furthermore, the natural surface of the arch itself has local elevation variations. If the actual surface positions corresponding to two consecutive measurements differ, the local elevation difference may be mistaken for arch displacement, affecting the comparability of measurement data between different monitoring periods.

[0005] Furthermore, when using the measuring point at the bottom of the tunnel as the laser distance measurement benchmark, the measurement results are not only affected by the displacement of the tunnel crown itself, but may also be affected by changes in the installation position and attitude of the monitoring unit, as well as changes in the state of the bottom measurement benchmark. If only the laser distance during the benchmark monitoring period is directly subtracted from the current laser distance, the aforementioned changes in the measurement benchmark may be superimposed on the tunnel crown settlement calculation results. The settlement calculation method mainly involves comparing the current measurement distance with the initial benchmark distance.

[0006] To address this, a laser monitoring method and system for the settlement of the tunnel arch during operation is proposed. Summary of the Invention

[0007] The main objective of this invention is to provide a laser monitoring method and system for the settlement of the arch of a subway tunnel during operation, which can effectively solve the problems in the background art.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A laser monitoring method for settlement of the arch of a subway tunnel during operation includes the following steps:

[0010] S1. Determine the bottom reference measuring point on the monitoring section of the target subway tunnel, and position the laser monitoring unit at the predetermined measurement position and measurement direction corresponding to the bottom reference measuring point. Obtain the initial attitude state of the laser monitoring unit, and control the laser monitoring unit to obtain the initial distance data corresponding to multiple sampling positions in the arch target area.

[0011] S2. Extract local surface features formed by local undulations of the natural surface of the arch based on the initial distance data, establish a reference surface feature template corresponding to the monitoring section based on the local surface features, and determine the reference natural measurement position and the reference measurement distance corresponding to the reference natural measurement position from the target area of ​​the arch.

[0012] S3. During the subsequent monitoring period, the laser monitoring unit is positioned at the measurement position and measurement direction corresponding to the bottom reference measurement point, the current attitude state of the laser monitoring unit is obtained, and the current reference measurement information corresponding to at least one preset reference area is obtained. The measurement reference correction amount corresponding to the current monitoring period is determined based on the change of the current attitude state and the current reference measurement information relative to the reference monitoring period.

[0013] S4. Obtain multiple current distance data corresponding to the target area of ​​the arch during the current monitoring period, extract current local surface features from the multiple current distance data, match the current local surface features with the reference surface feature template, and determine the current natural measurement position corresponding to the reference natural measurement position based on the matching result.

[0014] S5. Obtain the current measurement distance corresponding to the current natural measurement position, correct the distance change between the reference measurement distance and the current measurement distance according to the measurement reference correction amount, and determine the vertical displacement of the arch corresponding to the current monitoring period.

[0015] S6. Determine the cumulative settlement and settlement trend based on the vertical displacement of the arch crown corresponding to multiple consecutive monitoring periods, and generate arch crown settlement early warning information when the cumulative settlement or the settlement trend meets the preset early warning conditions.

[0016] Furthermore, in steps S1 and S3, the installation position and installation direction of the laser monitoring unit relative to the bottom reference measuring point are determined by the positioning structure, positioning mark or position identification information corresponding to the bottom reference measuring point, so that the laser monitoring unit at different monitoring periods can be restored to the corresponding predetermined measurement position and measurement direction.

[0017] The attitude detection unit obtains the attitude angles of the laser monitoring unit along at least two mutually perpendicular directions, and adjusts the measured attitude of the laser monitoring unit according to the attitude angles so that the adjusted attitude angles are within the preset attitude allowable range.

[0018] Furthermore, in step S1, initial distance data corresponding to multiple sampling positions within the target area of ​​the dome are obtained by changing the laser measurement direction or by using multiple preset measurement directions;

[0019] In step S2, at least two feature parameters among the local elevation difference, surface gradient, local curvature, and distance profile corresponding to each sampling position are determined based on the initial distance data corresponding to the multiple sampling positions, and the local surface features are constructed based on the feature parameters.

[0020] Based on the degree of distinguishability between local surface features corresponding to different sampling locations, at least one location with reproducible natural surface features is determined from the target area of ​​the arch as the reference natural measurement location, and the local surface features in the neighborhood of the reference natural measurement location are saved as the reference surface feature template.

[0021] Furthermore, in step S4, for multiple candidate natural measurement locations obtained during the current monitoring period, the feature matching cost between the current local surface features corresponding to each candidate natural measurement location and the reference surface feature template is calculated respectively:

[0022]

[0023] in, Indicates the first Feature matching cost corresponding to each candidate natural measurement location; Indicates the first Distance profile differences corresponding to each candidate natural measurement location; Indicates the first The surface gradient differences corresponding to each candidate natural measurement location; Indicates the first Local curvature differences corresponding to each candidate natural measurement location; , and Let each represent the weight of the corresponding difference term, and satisfy the following:

[0024]

[0025] as well as:

[0026]

[0027] The preset matching conditions and the feature matching cost will be satisfied. The smallest candidate natural measurement location is determined as the current natural measurement location.

[0028] Furthermore, for including The first corresponding sampling point The distance profile difference between the candidate natural measurement locations is determined according to the following formula:

[0029]

[0030] The surface gradient difference is determined according to the following formula:

[0031]

[0032] The local curvature difference is determined according to the following formula:

[0033]

[0034] in, Indicates the first Within the neighborhood of the candidate natural measurement location, the first The current measurement distance corresponding to each sampling point; This represents the average current measurement distance of each sampling point within the neighborhood of the candidate natural measurement location; The first in the reference surface feature template The reference measurement distance for each corresponding sampling point; This represents the average value of the reference measurement distance at each sampling point in the reference surface feature template; and These represent the current monitoring period and the baseline monitoring period, respectively. The surface gradient of each corresponding sampling point; and These represent the current monitoring period and the baseline monitoring period, respectively. Local curvature of each corresponding sampling point; , and These represent the normalized scale parameters corresponding to the differences in distance profile, surface gradient, and local curvature, respectively.

[0035] Furthermore, in step S3, the preset reference area includes at least two reference areas that are spatially separated from the target area of ​​the vault.

[0036] During the baseline monitoring period, the baseline reference distance corresponding to each preset reference area is obtained. During the current monitoring period, the current reference distance corresponding to each preset reference area is obtained. Based on the current attitude state of the laser monitoring unit, the current reference distance is subjected to attitude compensation and equivalent projection along the main measurement direction of the arch to obtain the current equivalent reference distance corresponding to each preset reference area.

[0037] Current monitoring period The corresponding measurement reference correction amount is determined according to the following formula:

[0038]

[0039] in, Indicates the current monitoring period The corresponding measurement reference correction amount; This indicates the number of the preset reference regions, and ; Indicates the first The current equivalent reference distance of a preset reference area after attitude compensation and equivalent projection during the current monitoring period; Indicates the first The benchmark equivalent reference distance for each preset reference area during the benchmark monitoring period; Indicates the first Correction weights corresponding to each preset reference region, satisfying:

[0040]

[0041] as well as .

[0042] Furthermore, the vertical displacement of the arch from the reference position towards the tunnel interior is defined as a positive value, during the current monitoring period. The corresponding vertical displacement of the arch is determined by the following formula:

[0043]

[0044] in, Indicates the current monitoring period The corresponding vertical displacement of the arch; This indicates the reference measurement distance corresponding to the reference natural measurement position; This indicates the current measurement distance corresponding to the current natural measurement position determined by matching the reference surface feature template; This indicates the measurement baseline correction amount corresponding to the current monitoring period;

[0045] when At that time, it indicates that the natural measurement position of the arch has undergone vertical displacement into the tunnel relative to the reference monitoring period.

[0046] Furthermore, within each monitoring period, multiple laser ranging operations are performed on the current natural measurement location to obtain multiple repeated measurement distances. Abnormal measurement data are identified and eliminated based on the dispersion among the multiple repeated measurement distances, and the current measurement distance is determined based on the retained valid measurement data.

[0047]

[0048] in, This represents the set of valid measurement data retained after removing abnormal measurement data during the current monitoring period t; This indicates the number of valid measurement data points contained in the valid measurement data set; Indicates the number of the current monitoring period One effective measurement distance;

[0049] When the matching degree between the current local surface feature and the reference surface feature template does not meet the preset matching conditions, the dispersion of the effective measurement data exceeds the preset dispersion threshold, or the measurement change of the preset reference area exceeds the preset reference stability threshold, the current monitoring result is marked as data to be reviewed.

[0050] The subsequent monitoring period includes the train shutdown window of the subway tunnel. During the train shutdown window, the laser monitoring unit is controlled to perform attitude adjustment, reference area measurement and arch target area measurement, and the laser monitoring unit enters a low power consumption state after the monitoring data transmission is completed.

[0051] A laser monitoring system for settlement of the arch of a subway tunnel during operation includes a bottom reference component, a laser monitoring unit, a measurement direction adjustment unit, an attitude detection and adjustment unit, a control unit, a communication unit, and a data processing terminal;

[0052] The bottom reference component is set on the monitoring section of the subway tunnel to determine the measurement reference position corresponding to the laser monitoring unit;

[0053] The laser monitoring unit is used to acquire laser distance data corresponding to the target area of ​​the dome and the preset reference area;

[0054] The measurement direction adjustment unit is used to change the laser measurement direction of the laser monitoring unit, so that the laser monitoring unit can acquire distance data corresponding to multiple sampling positions within the target area of ​​the dome.

[0055] The attitude detection and adjustment unit is used to acquire the attitude state of the laser monitoring unit and adjust the measurement attitude of the laser monitoring unit according to the attitude state.

[0056] The control unit is used to control the laser monitoring unit, the measurement direction adjustment unit, and the attitude detection and adjustment unit to perform monitoring operations.

[0057] The communication unit is used to send monitoring data to the data processing terminal;

[0058] The data processing terminal is equipped with a reference surface feature establishment module, a natural measurement position matching module, a measurement reference correction module, a vertical displacement calculation module, and a settlement trend analysis module.

[0059] The reference surface feature establishment module is used to establish a reference surface feature template based on the distance data of the arch target area obtained during the reference monitoring period, and to determine the reference natural measurement position;

[0060] The natural measurement location matching module is used to match the current local surface features corresponding to the current monitoring period with the reference surface feature template, and determine the current natural measurement location based on the matching result;

[0061] The measurement reference correction module is used to determine the measurement reference correction amount based on the change of the current reference measurement information of the preset reference area relative to the reference monitoring period and the current attitude state of the laser monitoring unit;

[0062] The vertical displacement calculation module is used to determine the vertical displacement of the arch based on the reference measurement distance corresponding to the reference natural measurement position, the current measurement distance corresponding to the current natural measurement position, and the measurement reference correction amount;

[0063] The settlement trend analysis module is used to determine the cumulative settlement and settlement trend based on the vertical displacement of the arch crown corresponding to multiple consecutive monitoring periods, and output arch crown settlement early warning information according to preset early warning conditions.

[0064] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] 1. By acquiring distance data corresponding to multiple sampling locations within the target area of ​​the arch, local surface features formed by local undulations of the natural surface of the arch are extracted, a benchmark surface feature template is established, and the current local surface features are matched with the benchmark surface feature template during subsequent monitoring periods, thereby re-determining the current natural measurement position corresponding to the benchmark natural measurement position. There is no need to set up artificial targets, reflection marks or contact displacement probes on the arch, and the measurement deviation caused by changes in the laser irradiation position in different measurements is reduced.

[0067] 2. The measurement position and direction of the laser monitoring unit are determined by the bottom reference measuring point. The measurement reference correction amount is determined by combining the attitude state of the laser monitoring unit and the reference measurement information of the preset reference area. The distance change between the reference measurement distance and the current measurement distance is corrected, thereby reducing the impact of the installation state, attitude state and measurement reference changes of the monitoring unit on the calculation results of the vertical displacement of the arch and improving the comparability between long-term periodic monitoring data.

[0068] 3. By constructing feature matching costs through distance contour differences, surface gradient differences, and local curvature differences, and comparing the distance contours after removing the local average distance, the identification of natural measurement positions is mainly based on local surface shape features, thereby reducing the impact of the overall vertical translation of the arch on the feature matching results. This is beneficial for the stable identification of the same natural surface position under conditions without artificial targets.

[0069] 4. During the train shutdown window, the system can automatically perform attitude adjustment, reference area measurement, arch target area measurement, and monitoring data transmission. It can also check the validity of the current monitoring results through multiple laser ranging, abnormal data removal, matching status judgment, and benchmark stability judgment. Combined with the vertical displacement of the arch over multiple consecutive monitoring periods, it can further obtain the cumulative settlement and settlement trend. When the preset conditions are met, it can generate early warning information, thereby reducing on-site manual measurement and repetitive deployment work, and improving the continuity of tunnel arch settlement monitoring during operation. Attached Figure Description

[0070] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0071] Figure 2 This is a schematic diagram of the system modules of the present invention. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0073] Example 1

[0074] like Figure 1-2 As shown, a laser monitoring method for the settlement of the arch of a subway tunnel during operation is described. This embodiment is applied to the periodic monitoring of the settlement of the arch of a subway tunnel during operation. Multiple monitoring sections are selected at predetermined intervals inside the subway tunnel. At least one bottom reference measuring point is set in each monitoring section, and a corresponding laser monitoring unit is configured for each bottom reference measuring point.

[0075] The laser monitoring unit includes at least a laser ranging module, an attitude detection unit, a measurement direction adjustment unit, a control unit, and a communication unit. The laser ranging module is used to acquire the distance between the laser emission position and the natural surface of the tunnel arch or a preset reference area; the attitude detection unit may employ a dual-axis tilt sensor to acquire the attitude angles of the laser monitoring unit along two mutually perpendicular directions; the measurement direction adjustment unit is used to change the laser measurement direction so that the laser beam can cover the predetermined arch target area; and the control unit is used to perform device wake-up, attitude adjustment, distance sampling, scan control, and data transmission.

[0076] A laser monitoring unit can be installed at a permanent reference position at the bottom of the tunnel, and the consistency of measurement posture during different monitoring periods can be improved through automatic leveling. In this embodiment, periodic settlement monitoring is further achieved by combining repeated positioning on the natural surface and correction of the measurement reference.

[0077] Specifically, it includes the following steps.

[0078] S1. Determine the bottom reference measuring point and perform initial measurements.

[0079] First, multiple monitoring sections are determined based on the structural form, location of defects, and monitoring requirements of the subway tunnel to be monitored.

[0080] For example, monitoring sections can be set up at preset distances along the longitudinal direction of the tunnel, or monitoring sections can be set up more densely in existing areas with abnormal deformation, areas with lining cracks, or areas where geological conditions have changed.

[0081] For any monitoring section, determine the bottom reference measuring point at the bottom of the tunnel.

[0082] The bottom reference measurement point is mainly used to determine the measurement reference position of the laser monitoring unit corresponding to different monitoring periods. It can adopt a mechanical positioning structure, positioning mark, coordinate mark, visual positioning mark or other positioning method that can restore the laser monitoring unit to the predetermined measurement position and measurement direction, and is not limited to a specific mechanical structure.

[0083] When performing the initial benchmark monitoring, position the laser monitoring unit at the predetermined measurement position corresponding to the bottom benchmark measurement point.

[0084] The initial attitude state is obtained through the attitude detection unit, for example, by obtaining the tilt angles in two mutually perpendicular directions:

[0085]

[0086] in, and These represent the attitude angles of the laser monitoring unit along the first attitude direction and the second attitude direction during the reference monitoring period, respectively.

[0087] When the attitude angle exceeds the preset attitude allowable range, the attitude of the laser monitoring unit is adjusted by the measurement direction adjustment unit or the independent leveling mechanism until it meets the preset measurement requirements.

[0088] The target area for the dome was then determined.

[0089] The target area of ​​the arch is not a single artificial marker point, but a natural concrete surface area within a certain spatial range near the arch of the monitoring section.

[0090] The laser monitoring unit is controlled to acquire initial distance data corresponding to multiple sampling positions within a preset measurement angular domain.

[0091] Assuming a total of With 1 initial sampling point, an initial distance data set is formed:

[0092]

[0093] in, Indicates the benchmark monitoring period number The laser measurement distance corresponding to each sampling position.

[0094] In practice, the direction of the laser beam can be continuously changed by an electric gimbal, or the distance measurement of different sampling positions can be achieved by a MEMS reflection mechanism, a mirror mechanism, or multiple preset laser directions. Therefore, this invention does not limit the specific form of the scanning mechanism.

[0095] S2. Establish a reference surface feature template for the natural surface of the vault.

[0096] Because the natural surface of the concrete in the arch of a subway tunnel usually has slight bumps, construction textures and local curvature variations, there are still certain natural geometric differences between different local locations even without artificial targets.

[0097] This embodiment utilizes this natural surface difference for repeated measurement location identification.

[0098] Local analysis is performed on the initial distance data to obtain the distance profile, local elevation difference, surface gradient and local curvature in the neighborhood of different sampling positions.

[0099] For example, for the first For each sampling point, the surface gradient parameters can be determined based on the distance difference between it and its adjacent sampling points; the local curvature parameters can be determined based on the gradient changes corresponding to multiple consecutive sampling positions.

[0100] To prevent changes in absolute distance after vertical displacement of the entire vault from affecting the matching of the natural surface, local average distance removal can be performed first when establishing distance profile features.

[0101] For a given candidate local region, its average distance is:

[0102]

[0103] The corresponding relative distance profile can be represented as:

[0104]

[0105] In this way, even if the entire vault moves vertically in a similar manner, the local outline shape can remain basically unchanged.

[0106] Furthermore, a reference natural measurement location is selected based on the degree of distinguishability between local surface features in the neighborhood of different sampling locations.

[0107] The degree of distinguishability refers to the fact that the natural surface features formed in the neighborhood of a location are sufficiently different from other surrounding locations to be re-identified in the next scan.

[0108] For example, areas with overly flat surfaces and roughly uniform distances between different locations can be given lower priority as reference natural measurement locations; while areas with stable local protrusions, depressions, or curvature variations can be given priority as reference natural measurement locations.

[0109] After determining the reference natural measurement location, the corresponding distance profile, surface gradient, and local curvature in its neighborhood are saved as a reference surface feature template, and the reference measurement distance corresponding to that location is also saved. .

[0110] Therefore, there is no need to drill holes in the arch, attach targets, or set permanent contact measurement points. Instead, the natural surface features of the arch itself are used to establish a repeatable identification benchmark.

[0111] S3. Obtain the current attitude state and determine the measurement reference correction amount.

[0112] After entering the subsequent monitoring period, such as the next subway train shutdown window, the laser monitoring unit will be placed at the measurement position of the corresponding bottom reference point again.

[0113] Get the current attitude angle:

[0114]

[0115] in, This indicates the current monitoring period.

[0116] Compare the current attitude angle with the reference attitude state. For example:

[0117]

[0118]

[0119] When the attitude difference exceeds the allowable range, it is readjusted through the attitude adjustment mechanism.

[0120] Since attitude adjustment alone cannot completely eliminate the range measurement changes caused by changes in the bottom reference position or repeated installation deviations of the equipment, this embodiment further sets a preset reference area.

[0121] Preferably, at least two reference areas are set outside the target area of ​​the dome. The reference areas can be selected as relatively stable natural structural areas within the monitoring section that can be stably identified by the laser.

[0122] It should be noted that the so-called "reference area" does not necessarily require the setting of artificial reflective targets; it can also be the natural surface of the existing tunnel structure.

[0123] During the baseline monitoring period, the baseline reference distance for each reference area was obtained. For the first... A preset reference area is defined, and its baseline equivalent reference distance is denoted as:

[0124] The corresponding reference distance is acquired again during the current monitoring period. Since the current attitude of the laser monitoring unit may differ slightly from the baseline monitoring period, attitude compensation is first performed on the reference distance based on the current attitude state, and then an equivalent projection is performed according to the main measurement direction of the arch to obtain:

[0125] in, Indicates the first The current equivalent reference distance of a preset reference area after attitude compensation and equivalent projection during the current monitoring period.

[0126] Specifically, when there is an angle between the measurement beam and the main measurement direction In this case, the projection relationship from the reference distance to the main measurement direction can be established according to the actual equipment geometry. One example is as follows:

[0127]

[0128] in, Indicates the current monitoring period number The original measured distance corresponding to each reference area This indicates the angle between the corresponding measurement beam and the main measurement direction.

[0129] The above formula is only one specific projection method. In actual implementation, coordinate transformation can also be performed based on the three-dimensional attitude matrix of the laser monitoring unit and the direction vectors of each reference beam.

[0130] Then, the measurement reference correction amount is calculated:

[0131]

[0132] in, Indicates the current monitoring period The corresponding measurement reference correction amount; Indicates the number of preset reference areas, and:

[0133]

[0134] Indicates the first The current equivalent reference distance of each preset reference area during the current monitoring period; Indicates the first The baseline equivalent reference distance for each preset reference area; Indicates the first The corrected weights corresponding to each reference region satisfy the following conditions:

[0135]

[0136] as well as

[0137] For cases where both reference regions have similar stability, we can let:

[0138] When a reference region has higher long-term measurement stability, it can be assigned a higher weight.

[0139] In this way, the common distance change in the reference area can characterize the common distance offset caused by changes in the bottom measurement reference state or the installation state of the monitoring equipment, thereby compensating for it when calculating the crown displacement.

[0140] S4. Re-determine the same measurement location by matching natural surface features.

[0141] After completing the equipment attitude check and reference area measurement, local measurements of the target area of ​​the arch are performed during the current monitoring period.

[0142] Get the current distance data set:

[0143]

[0144] The current local surface features are calculated according to the feature extraction rules that are the same as or correspond to the baseline monitoring period.

[0145] Multiple candidate natural measurement locations are set up near the baseline natural measurement location.

[0146] Regarding the first For each candidate natural measurement location, the distance profile difference, surface gradient difference, and local curvature difference are calculated.

[0147] The difference in distance profile is determined according to the following formula:

[0148]

[0149] in, Indicates the number of corresponding sampling points for which local feature comparisons are performed; Indicates the current number Within the neighborhood of the candidate natural measurement location, the first The measurement distance corresponding to each sampling point; Indicates the first The average of the current measurement distances of each sampling point within the neighborhood of each candidate natural measurement location; Indicating the first feature template of the reference surface The reference measurement distance for each corresponding sampling point; This represents the average distance corresponding to the reference surface feature template; Normalized scaling parameter representing the difference in distance profile.

[0150] The above calculation first subtracts the average distance of the current area and the average distance of the reference area respectively, and then compares the two local contours, thereby reducing the impact of the overall vertical translation of the arch on the local shape matching.

[0151] Surface gradient differences are calculated using the following formula:

[0152]

[0153] in, Indicates the current candidate position. The surface gradient of each corresponding sampling point Indicating the first feature template of the reference surface The surface gradient of each corresponding sampling point This is the normalized scale parameter for the surface gradient.

[0154] Local curvature differences are calculated using the following formula:

[0155]

[0156] in, and These represent the local curvature of the sampling points corresponding to the current monitoring period and the baseline monitoring period, respectively. This is the local curvature normalization scale parameter.

[0157] The combined results are as follows: Feature matching cost for candidate positions:

[0158]

[0159] in:

[0160]

[0161] and:

[0162]

[0163] For example, in one specific embodiment, the following can be configured:

[0164]

[0165] However, the above values ​​are for illustrative purposes only and do not constitute a limitation of the present invention.

[0166] First, exclude candidate positions whose matching cost exceeds a preset threshold from all candidate positions, and then select from the remaining candidate positions:

[0167]

[0168] The first The candidate natural measurement locations are selected as the current natural measurement location.

[0169] Therefore, even if there is a slight difference in lateral position or angular deviation in the laser monitoring unit during the two installation processes, it can be repositioned to the natural surface position corresponding to the reference monitoring period through natural surface features, rather than simply requiring the laser beam to mechanically repeat falling on the theoretically fixed coordinate position.

[0170] S5. Determine the current measurement distance and the vertical displacement of the arch crown.

[0171] Once the current natural measurement location is determined, multiple repeated distance measurements can be performed at that location. For example, continuous distance measurements can be obtained within a monitoring period.

[0172]

[0173] First, anomaly identification is performed on the repeated measurement data.

[0174] Outlier identification can employ methods based on the mean and standard deviation, the median absolute deviation, or other anomaly detection methods suitable for laser distance data.

[0175] After removing outlier data, a valid set of measurement data is formed:

[0176]

[0177] Assume the number of valid data is Then the current measured distance of the current natural measurement location is:

[0178]

[0179] in, Indicates the number of the current monitoring period One effective measurement distance.

[0180] Then the distance was measured according to the benchmark. Current measured distance and measurement reference correction amount Determine the vertical displacement of the arch crown:

[0181]

[0182] in, Indicates the current monitoring period The corresponding vertical displacement of the arch; This indicates the reference measurement distance corresponding to the reference natural measurement location during the reference monitoring period; This indicates the current measurement distance corresponding to the current natural measurement location within the current monitoring period; This indicates the measurement baseline correction amount corresponding to the current monitoring period.

[0183] In this embodiment, the vertical displacement of the arch from the reference position towards the tunnel interior is defined as positive. Therefore:

[0184]

[0185] This indicates a vertical displacement of the arch towards the interior of the tunnel, commonly known as arch settlement.

[0186] For example, if the reference measurement distance is:

[0187]

[0188] The current measured distance is:

[0189]

[0190] Simultaneously, based on calculations from the reference area:

[0191]

[0192] but:

[0193]

[0194] Right now:

[0195]

[0196] This indicates that, after correction for changes in the measurement baseline, this location has shifted approximately [percentage missing] into the tunnel relative to the baseline monitoring period. Vertical displacement.

[0197] It should be noted that, The positive or negative value is determined by the direction of change of the current equivalent reference distance of the reference area relative to the benchmark equivalent reference distance, so it is not a fixed positive compensation term.

[0198] S6. Judgment of the validity of monitoring results

[0199] To prevent distortion of single monitoring results due to abnormal changes in natural surface features, collisions to equipment, or localized damage to the reference area, this embodiment further includes a measurement validity judgment mechanism.

[0200] The judgment should be made based on at least one or more of the following three states: the first state is the natural surface feature matching state; the second state is the repeated distance measurement dispersion state; and the third state is the reference area benchmark stability state.

[0201] For example, when the optimal feature matching cost satisfies:

[0202]

[0203] in, When the preset matching threshold is used, it indicates that the current scan area cannot reliably find a position corresponding to the reference natural measurement position.

[0204] Instead of directly updating the long-term settlement curve using this result, it is marked as data to be reviewed.

[0205] For repeated measures data, its standard deviation can be calculated:

[0206]

[0207] when: If the current repeated measurement shows excessive dispersion, the monitoring result can be marked as data to be reviewed.

[0208] For reference areas, if the distance change of any reference area significantly exceeds the preset allowable range, or if there is a significant inconsistency between multiple reference areas, it indicates that the current bottom benchmark or reference area may be abnormal, and the final settlement value can be output directly without interruption.

[0209] The above mechanism can prevent single erroneous data from being directly incorporated into historical subsidence trends.

[0210] S7. Cumulative Settlement and Settlement Trend Analysis

[0211] For monitoring data that has passed the validity assessment, the vertical displacement of the arch corresponding to each monitoring period is saved in chronological order.

[0212] For monitoring periods:

[0213]

[0214] Forming a vertical displacement sequence:

[0215]

[0216] The cumulative settlement relative to the baseline monitoring period can be directly determined based on the latest monitoring results.

[0217] Simultaneously, the rate of settlement change can be calculated based on adjacent monitoring periods. For example:

[0218]

[0219] in, This indicates the average rate of settlement change between the current monitoring period and the previous valid monitoring period.

[0220] When the cumulative settlement exceeds the preset cumulative settlement threshold, the settlement rate exceeds the preset rate threshold, or multiple consecutive monitoring periods show an increasing trend in the same direction, a corresponding level of arch settlement early warning information is generated.

[0221] In actual use, different warning thresholds can be set according to different line grades, tunnel structure types and subway operation and maintenance requirements. This invention does not limit the specific threshold values.

[0222] S8 Automatic Monitoring of Train Stoppage Window Periods

[0223] Preferably, the subsequent monitoring period is selected during the maintenance window when the subway trains are out of service.

[0224] In this embodiment, the skylight time plan can be saved in the control unit in advance. After the preset monitoring time is reached, the following steps are executed in sequence: device wake-up, attitude status acquisition, necessary attitude adjustment, measurement of preset reference area, local scanning of the arch target area, natural surface feature matching, repeated laser ranging at the current natural measurement position, and sending the measurement data to the data processing terminal. After the data transmission is completed, the device enters a low-power state.

[0225] By adopting the above method, on-site manual intervention can be mainly limited to equipment installation, maintenance, and anomaly verification, while routine periodic measurements can be completed automatically.

[0226] It should be noted that the main purpose of this invention in utilizing the maintenance window is to reduce dynamic disturbances caused by train operation, rather than to limit the absence of any environmental vibrations during the maintenance window.

[0227] Example of baseline state correction

[0228] To further illustrate the principle of measurement benchmark correction, let's take two preset reference areas as an example.

[0229] Let the two reference regions be the first reference region and the second reference region, respectively. After equivalent projection during the baseline monitoring period, we obtain:

[0230]

[0231]

[0232] During the current monitoring period, the following was obtained:

[0233]

[0234]

[0235] When the weights corresponding to the two reference regions are respectively:

[0236]

[0237] but:

[0238]

[0239] Therefore, we can conclude that:

[0240]

[0241] That is, the current measurement system has generated approximately [a certain amount] compared to the baseline monitoring period. Changes in the equivalent benchmark.

[0242] If we use it directly at this point:

[0243]

[0244] The crown displacement is calculated, and this baseline change is superimposed into the crown displacement result. This is achieved by introducing... Making corrections can reduce misjudgments caused by such benchmark changes.

[0245] Example of targetless natural measurement position matching

[0246] At a certain monitoring section, multiple local candidate locations were obtained during the initial scanning of the arch target area. After analysis, one location with obvious local concavity and convexity features was selected as the benchmark natural measurement location.

[0247] In the next monitoring period, due to slight positional deviations caused by repeated installation of the monitoring equipment, three candidate locations were obtained in the current scanning area, with corresponding feature matching costs as follows:

[0248]

[0249]

[0250]

[0251] If a preset matching threshold is used:

[0252]

[0253] Then only the second candidate natural measurement position satisfies a high degree of matching, and:

[0254]

[0255] Therefore, the second candidate natural measurement location is determined as the current natural measurement location.

[0256] Subsequently, instead of using the distance corresponding to the scan center location, the distance corresponding to the second candidate natural measurement location was used as... This avoids misjudging local height differences on natural surfaces as arch settlement due to changes in the laser beam's landing point caused by repeated equipment installation.

[0257] Monitoring System

[0258] Corresponding to the above method, this embodiment provides a laser monitoring system for the settlement of the arch of a subway tunnel during operation, including a bottom reference component, a laser monitoring unit, a measurement direction adjustment unit, an attitude detection and adjustment unit, a control unit, a communication unit, and a data processing terminal.

[0259] The bottom reference component is used to provide a repeatable measurement reference position for different monitoring periods.

[0260] The laser monitoring unit is used to emit measuring lasers to the target area of ​​the dome and the preset reference area, and to acquire the corresponding distance data.

[0261] The measurement direction adjustment unit is used to control the laser beam to acquire distance information at different sampling positions according to multiple preset directions.

[0262] The attitude detection and adjustment unit is used to obtain the attitude state of the laser monitoring unit and to measure and adjust the attitude.

[0263] The data processing terminal includes a reference surface feature establishment module, a natural measurement location matching module, a measurement reference correction module, a vertical displacement calculation module, and a settlement trend analysis module.

[0264] The benchmark surface feature establishment module is used to process multiple initial distance data during the benchmark monitoring period, obtain features such as local distance profile, surface gradient and local curvature of the natural surface of the arch, and establish benchmark surface feature templates.

[0265] The natural measurement location matching module is used to match features based on the cost. Find the current natural measurement position in the current scan data that corresponds to the reference natural measurement position.

[0266] The measurement reference correction module is used to determine the measurement reference correction amount based on the equivalent reference distance of each preset reference area and the current equivalent reference distance. .

[0267] The vertical displacement calculation module is used to calculate according to:

[0268]

[0269] Determine the vertical displacement of the arch.

[0270] The settlement trend analysis module is used to save the vertical displacement results corresponding to each monitoring period, form time-settlement change data, and generate early warning information based on the cumulative settlement, settlement change rate, and continuous change status.

[0271] Through the above implementation methods, the present invention does not simply replace the existing contact displacement probe with laser ranging. Instead, it forms a complete arch settlement monitoring process by restoring the bottom measurement benchmark, establishing the arch crown natural surface feature template, repeatedly identifying the targetless natural position, correcting the reference area measurement benchmark, and performing multi-time period trend analysis. This improves the data comparability and measurement reliability between different measurements in the periodic non-contact settlement monitoring of subway tunnels during operation.

[0272] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A laser monitoring method for settlement of the arch of a subway tunnel during operation, characterized in that, Includes the following steps: S1. Determine the bottom reference measuring point on the monitoring section of the target subway tunnel, and position the laser monitoring unit at the predetermined measurement position and measurement direction corresponding to the bottom reference measuring point. Obtain the initial attitude state of the laser monitoring unit, and control the laser monitoring unit to obtain the initial distance data corresponding to multiple sampling positions in the arch target area. S2. Extract local surface features formed by local undulations of the natural surface of the arch based on the initial distance data, establish a reference surface feature template corresponding to the monitoring section based on the local surface features, and determine the reference natural measurement position and the reference measurement distance corresponding to the reference natural measurement position from the target area of ​​the arch. S3. During the subsequent monitoring period, the laser monitoring unit is positioned at the measurement position and measurement direction corresponding to the bottom reference measurement point, the current attitude state of the laser monitoring unit is obtained, and the current reference measurement information corresponding to at least one preset reference area is obtained. The measurement reference correction amount corresponding to the current monitoring period is determined based on the change of the current attitude state and the current reference measurement information relative to the reference monitoring period. S4. Obtain multiple current distance data corresponding to the target area of ​​the arch during the current monitoring period, extract current local surface features from the multiple current distance data, match the current local surface features with the reference surface feature template, and determine the current natural measurement position corresponding to the reference natural measurement position based on the matching result. S5. Obtain the current measurement distance corresponding to the current natural measurement position, correct the distance change between the reference measurement distance and the current measurement distance according to the measurement reference correction amount, and determine the vertical displacement of the arch corresponding to the current monitoring period. S6. Determine the cumulative settlement and settlement trend based on the vertical displacement of the arch crown corresponding to multiple consecutive monitoring periods, and generate arch crown settlement early warning information when the cumulative settlement or the settlement trend meets the preset early warning conditions.

2. The laser monitoring method for settlement of the arch of a subway tunnel during operation, as described in claim 1, is characterized in that... In steps S1 and S3, the installation position and installation direction of the laser monitoring unit relative to the bottom reference measuring point are determined by the positioning structure, positioning mark or position identification information corresponding to the bottom reference measuring point, so that the laser monitoring unit at different monitoring periods can be restored to the corresponding predetermined measurement position and measurement direction. The attitude detection unit obtains the attitude angles of the laser monitoring unit along at least two mutually perpendicular directions, and adjusts the measured attitude of the laser monitoring unit according to the attitude angles so that the adjusted attitude angles are within the preset attitude allowable range.

3. The laser monitoring method for settlement of the arch of a subway tunnel during operation, as described in claim 1, is characterized in that... In step S1, initial distance data corresponding to multiple sampling positions within the target area of ​​the dome are obtained by changing the laser measurement direction or by using multiple preset measurement directions; In step S2, at least two feature parameters among the local elevation difference, surface gradient, local curvature, and distance profile corresponding to each sampling position are determined based on the initial distance data corresponding to the multiple sampling positions, and the local surface features are constructed based on the feature parameters. Based on the degree of distinguishability between local surface features corresponding to different sampling locations, at least one location with reproducible natural surface features is determined from the target area of ​​the arch as the reference natural measurement location, and the local surface features in the neighborhood of the reference natural measurement location are saved as the reference surface feature template.

4. The laser monitoring method for settlement of the arch of a subway tunnel during operation, as described in claim 3, is characterized in that... In step S4, for multiple candidate natural measurement locations obtained during the current monitoring period, the feature matching cost between the current local surface features corresponding to each candidate natural measurement location and the reference surface feature template is calculated: in, Indicates the first Feature matching cost corresponding to each candidate natural measurement location; Indicates the first Distance profile differences corresponding to each candidate natural measurement location; Indicates the first The surface gradient differences corresponding to each candidate natural measurement location; Indicates the first Local curvature differences corresponding to each candidate natural measurement location; , and Let each represent the weight of the corresponding difference term, and satisfy the following: as well as: The preset matching conditions and the feature matching cost will be satisfied. The smallest candidate natural measurement position is determined as the current natural measurement position.

5. The laser monitoring method for settlement of the arch of a subway tunnel during operation, as described in claim 4, is characterized in that... For including The first corresponding sampling point The distance profile difference between the candidate natural measurement locations is determined according to the following formula: The surface gradient difference is determined according to the following formula: The local curvature difference is determined according to the following formula: in, Indicates the first Within the neighborhood of the candidate natural measurement location, the first The current measurement distance corresponding to each sampling point; This represents the average current measurement distance of each sampling point within the neighborhood of the candidate natural measurement location; The first in the reference surface feature template The reference measurement distance for each corresponding sampling point; This represents the average value of the reference measurement distance at each sampling point in the reference surface feature template; and These represent the current monitoring period and the baseline monitoring period, respectively. The surface gradient of each corresponding sampling point; and These represent the current monitoring period and the baseline monitoring period, respectively. Local curvature of each corresponding sampling point; , and These represent the normalized scale parameters corresponding to the differences in distance profile, surface gradient, and local curvature, respectively.

6. The laser monitoring method for settlement of the arch of a subway tunnel during operation, as described in claim 1, is characterized in that... In step S3, the preset reference area includes at least two reference areas that are spatially separated from the target area of ​​the vault. During the baseline monitoring period, the baseline reference distance corresponding to each preset reference area is obtained. During the current monitoring period, the current reference distance corresponding to each preset reference area is obtained. Based on the current attitude state of the laser monitoring unit, the current reference distance is subjected to attitude compensation and equivalent projection along the main measurement direction of the arch to obtain the current equivalent reference distance corresponding to each preset reference area. Current monitoring period The corresponding measurement reference correction amount is determined according to the following formula: in, Indicates the current monitoring period The corresponding measurement reference correction amount; This indicates the number of the preset reference regions, and ; Indicates the first The current equivalent reference distance of a preset reference area after attitude compensation and equivalent projection during the current monitoring period; Indicates the first The benchmark equivalent reference distance for each preset reference area during the benchmark monitoring period; Indicates the first Correction weights corresponding to each preset reference region, satisfying: as well as .

7. The laser monitoring method for settlement of the arch of a subway tunnel during operation, as described in claim 6, is characterized in that... The vertical displacement of the arch from the reference position towards the tunnel interior is defined as a positive value, and the current monitoring period is... The corresponding vertical displacement of the arch is determined by the following formula: in, Indicates the current monitoring period The corresponding vertical displacement of the arch; This indicates the reference measurement distance corresponding to the reference natural measurement position; This indicates the current measurement distance corresponding to the current natural measurement position determined by the matching of the reference surface feature template; This indicates the measurement baseline correction amount corresponding to the current monitoring period; when At that time, it indicates that the natural measurement position of the arch has undergone vertical displacement into the tunnel relative to the reference monitoring period.

8. The laser monitoring method for settlement of the arch of a subway tunnel during operation, as described in claim 1, is characterized in that... Within each monitoring period, multiple laser ranging operations are performed on the current natural measurement location to obtain multiple repeated measurement distances. Abnormal measurement data are identified and discarded based on the dispersion among the multiple repeated measurement distances, and the current measurement distance is determined based on the retained valid measurement data. in, This represents the set of valid measurement data retained after removing abnormal measurement data during the current monitoring period t; This indicates the number of valid measurement data points contained in the valid measurement data set; Indicates the number of the current monitoring period One effective measurement distance; When the matching degree between the current local surface feature and the reference surface feature template does not meet the preset matching conditions, the dispersion of the effective measurement data exceeds the preset dispersion threshold, or the measurement change of the preset reference area exceeds the preset reference stability threshold, the current monitoring result is marked as data to be reviewed. The subsequent monitoring period includes the train shutdown window of the subway tunnel. During the train shutdown window, the laser monitoring unit is controlled to perform attitude adjustment, reference area measurement and arch target area measurement, and the laser monitoring unit enters a low power consumption state after the monitoring data transmission is completed.

9. A laser monitoring system for settlement of the arch of a subway tunnel during operation, characterized in that, It includes a bottom reference component, a laser monitoring unit, a measurement direction adjustment unit, an attitude detection and adjustment unit, a control unit, a communication unit, and a data processing terminal; The bottom reference component is set on the monitoring section of the subway tunnel to determine the measurement reference position corresponding to the laser monitoring unit; The laser monitoring unit is used to acquire laser distance data corresponding to the target area of ​​the dome and the preset reference area; The measurement direction adjustment unit is used to change the laser measurement direction of the laser monitoring unit, so that the laser monitoring unit can acquire distance data corresponding to multiple sampling positions within the target area of ​​the dome. The attitude detection and adjustment unit is used to acquire the attitude state of the laser monitoring unit and adjust the measurement attitude of the laser monitoring unit according to the attitude state. The control unit is used to control the laser monitoring unit, the measurement direction adjustment unit, and the attitude detection and adjustment unit to perform monitoring operations. The communication unit is used to send monitoring data to the data processing terminal; The data processing terminal is equipped with a reference surface feature establishment module, a natural measurement position matching module, a measurement reference correction module, a vertical displacement calculation module, and a settlement trend analysis module. The reference surface feature establishment module is used to establish a reference surface feature template based on the distance data of the arch target area obtained during the reference monitoring period, and to determine the reference natural measurement position; The natural measurement location matching module is used to match the current local surface features corresponding to the current monitoring period with the reference surface feature template, and determine the current natural measurement location based on the matching result; The measurement reference correction module is used to determine the measurement reference correction amount based on the change of the current reference measurement information of the preset reference area relative to the reference monitoring period and the current attitude state of the laser monitoring unit; The vertical displacement calculation module is used to determine the vertical displacement of the arch based on the reference measurement distance corresponding to the reference natural measurement position, the current measurement distance corresponding to the current natural measurement position, and the measurement reference correction amount; The settlement trend analysis module is used to determine the cumulative settlement and settlement trend based on the vertical displacement of the arch crown corresponding to multiple consecutive monitoring periods, and output arch crown settlement early warning information according to preset early warning conditions.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method described in any one of claims 1 to 8.

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