A method and system for measuring thaw settlement of a highway embankment in a permafrost region

Abstract

The application discloses a kind of frozen earth area highway subgrade thawing settlement measurement method and system, it is related to data measurement management technical field, method includes: obtaining to be measured subgrade area, obtain multiple measurement directions, form the node sequence of each measurement direction, obtain blank measurement area;Obtain first time second time, obtain the first subgrade height sequence of first time, obtain the second subgrade height sequence of second time, obtain current subgrade height sequence;Obtain current trend value, obtain first historical trend value, obtain second historical trend value, obtain first difference, obtain second difference;If first difference and second difference are less than preset threshold value, according to each node sequence current subgrade height sequence, obtain the measurement result of each blank measurement area.The application has the advantages of accurate prediction, high-precision measurement and adaptive measurement.

Description

Technical Field

[0001] This invention relates to the field of data measurement and management technology, specifically to a method and system for measuring the thaw settlement of highway subgrade in permafrost regions. Background Technology

[0002] In permafrost regions, roadbeds are prone to settlement due to the phase change characteristics of the permafrost layer and fluctuations in ambient temperature, seriously threatening road safety. Conventional methods for measuring thaw settlement in permafrost roadbeds require densely distributed measurement nodes on the roadbed to obtain complete settlement data. However, in practical engineering, limitations imposed by terrain, cost, and harsh environments make it difficult to cover many areas with sensors, resulting in blank measurement zones (such as vegetation zones or areas covered by existing structures). To address this issue, existing technologies typically extrapolate trends to predict the settlement of blank areas based on settlement data from neighboring nodes; however, these existing methods have significant drawbacks.

[0003] Specifically, permafrost thawing and settlement processes are strongly temporally correlated. During some periods, the roadbed continues to subside, while during others it may thaw and rise. The settlement trend between adjacent moments can fluctuate dramatically (e.g., accelerated settlement abruptly changes to stable thawing). If only current node data is used to predict blank areas, ignoring the risk of abrupt changes, forced extrapolation during unstable phases (e.g., sudden changes in thawing and settlement rates) can lead to serious biases. Furthermore, permafrost thawing and settlement often develops in a strip along the road's direction, but local geological differences (e.g., ice wedge distribution) can cause vastly different settlement trends across different road sections. Directly using local trends from node sequences to predict extended sections may misjudge short-term or localized fluctuations (e.g., sudden collapse of a single node due to melting underground ice) as the overall trend, causing the predicted results for blank areas to deviate from reality. Finally, existing technologies lack a mechanism to assess the applicability of predictions. When historical data shows continuous trend fluctuations (e.g., repeated changes in settlement direction during the monitoring period), forced extrapolation will amplify errors, yet it cannot automatically avoid such high-risk scenarios. Summary of the Invention

[0004] To address the technical problems of existing technologies that cannot guarantee the reliability of predicting blank areas by identifying roadbed settlement trends under a sparse node layout, and cannot avoid prediction inaccuracies caused by dynamic phase changes of permafrost, local geological heterogeneity, and trend fluctuations, thus failing to achieve high-precision and adaptive measurement of settlement in blank areas of permafrost roadbeds, this invention provides a method and system for measuring the thaw settlement of highway roadbeds in permafrost regions.

[0005] A method for measuring the thaw settlement of highway subgrade in permafrost regions includes: acquiring the subgrade area to be measured, acquiring multiple measurement directions within the subgrade area, uniformly setting multiple measurement nodes along each measurement direction to form a node sequence for each measurement direction, and acquiring blank measurement areas within the subgrade area and along the extensions of each measurement direction; acquiring interval durations, acquiring a first time interval from the current time and a second time interval twice the current time, acquiring a first subgrade height sequence for each node sequence at the first time, and acquiring a second subgrade height sequence for each node sequence at the second time. Obtain the current roadbed height sequence of each node sequence at the current time; obtain the current trend value based on the current roadbed height sequence of each node sequence, obtain the first historical trend value based on the first roadbed height sequence of each node sequence, obtain the second historical trend value based on the second roadbed height sequence of each node sequence, obtain the first difference based on the current trend value and the first historical trend value, and obtain the second difference based on the first historical trend value and the second historical trend value; if both the first difference and the second difference are less than a preset threshold, obtain the blank measurement area in each measurement direction, and obtain the measurement result of each blank measurement area based on the current roadbed height sequence of each node sequence.

[0006] Optionally, obtaining the measurement results of each blank measurement area based on the current subgrade height sequence of each node sequence includes: using the current trend value in each measurement direction as the first predicted trend value of each blank measurement area; correcting the first predicted trend value based on the first difference and the second difference to obtain the second predicted trend value; obtaining the last current subgrade height data in the current subgrade height sequence of each node sequence as the starting subgrade height data, and obtaining the measurement results of each blank measurement area based on the second predicted trend value and the starting subgrade height data of each blank measurement area.

[0007] Optionally, correcting the first predicted trend value based on the first difference and the second difference to obtain the second predicted trend value includes: when the first difference and the second difference reflect the same trend fluctuation direction, compensating the first predicted trend value in the same direction according to the fluctuation direction to obtain the second predicted trend value; when the first difference and the second difference reflect opposite trend fluctuation directions, using the first predicted trend value as the second predicted trend value.

[0008] Optionally, obtaining the measurement results of each blank measurement area based on the second predicted trend value and the initial roadbed height data of each blank measurement area includes: obtaining the distance between the blank measurement area of ​​each node sequence and each node sequence as the distance to be predicted; obtaining the rate of change of each blank measurement area based on the location range of each node sequence and the second predicted trend value of each blank measurement area; obtaining the amount of change based on the rate of change of each blank measurement area and the distance to be predicted, and obtaining the measurement results of each blank measurement area based on the amount of change and the initial roadbed height data.

[0009] Optionally, obtaining the current trend value based on the current subgrade height sequence of each node sequence includes: obtaining the current change in the current subgrade height data of adjacent measurement nodes in the node sequence; and accumulating all the current changes in the node sequence to obtain the current trend value.

[0010] Optionally, obtaining the first difference based on the current trend value and the first historical trend value includes: subtracting the first historical trend value from the current trend value and taking the absolute value to obtain the first difference.

[0011] A system for measuring the thaw settlement of roadbeds in permafrost regions is also provided. The system includes: a first data measurement module, used to acquire the roadbed area to be measured, acquire multiple measurement directions within the roadbed area, uniformly set multiple measurement nodes in each measurement direction to form a node sequence for each measurement direction, and acquire blank measurement areas located within the roadbed area and on the extensions of each measurement direction; a second data measurement module, used to acquire interval durations, acquire a first moment separated from the current moment by the interval duration, and a second moment separated from the current moment by twice the interval duration, acquire the first roadbed height sequence of each node sequence at the first moment, and acquire the second roadbed height sequence of each node sequence at the second moment. The system consists of a degree sequence and a data processing module, which obtains the current trend value based on the current roadbed height sequence of each node sequence, a first historical trend value based on the first roadbed height sequence of each node sequence, a second historical trend value based on the second roadbed height sequence of each node sequence, a first difference based on the current trend value and the first historical trend value, and a second difference based on the first historical trend value and the second historical trend value. A prediction measurement module is used to obtain blank measurement areas in each measurement direction if both the first difference and the second difference are less than a preset threshold, and to obtain the measurement results of each blank measurement area based on the current roadbed height sequence of each node sequence.

[0012] Optionally, the predictive measurement module is further configured to: use the current trend value in each measurement direction as the first predicted trend value for each blank measurement area; correct the first predicted trend value according to the first difference and the second difference to obtain the second predicted trend value; obtain the last current roadbed height data in the current roadbed height sequence of each node sequence and use it as the starting roadbed height data; and obtain the measurement results of each blank measurement area according to the second predicted trend value and the starting roadbed height data of each blank measurement area.

[0013] Optionally, the prediction measurement module is further configured to: when the trend fluctuation directions reflected by the first difference and the second difference are the same, compensate the first predicted trend value in the same direction according to the fluctuation direction, and obtain the second predicted trend value; when the trend fluctuation directions reflected by the first difference and the second difference are opposite, use the first predicted trend value as the second predicted trend value.

[0014] Optionally, the prediction measurement module is also used to: obtain the distance between the blank measurement area of ​​each node sequence and each node sequence and use it as the distance to be predicted; obtain the rate of change of each blank measurement area according to the position range of each node sequence and the second prediction trend value of each blank measurement area; obtain the amount of change according to the rate of change of each blank measurement area and the distance to be predicted, and obtain the measurement result of each blank measurement area according to the amount of change and the initial roadbed height data.

[0015] The beneficial effects of this invention are reflected in:

[0016] In the method for measuring roadbed thaw settlement in permafrost regions, firstly, by extracting three time-series roadbed height sequences—the current time, the time interval before, and twice the time interval before—and calculating the corresponding trend values ​​and trend differences, a dynamic discrimination mechanism for trend stability is constructed. Prediction is triggered only when both short-term (first difference) and medium-term (second difference) trend fluctuations are below a threshold, fundamentally avoiding the risk of forced extrapolation caused by sudden refreezing or accelerated thaw settlement in permafrost. Furthermore, combining the zonal characteristics of the measurement direction with a trend value correction strategy, in the prediction stage, the current trend value is used as a basis, and the trend difference is corrected based on its unidirectional nature. The dynamic correction (enhancing adjustment for unidirectional fluctuations and maintaining the original value for reverse fluctuations) utilizes the regularity of zonal settlement and offsets the interference of local geological heterogeneity (such as ice wedge abrupt changes and single-point collapses) through difference feedback, avoiding misjudging short-term fluctuations as overall trends. Furthermore, by using the measured height of the end node as the starting point, and combining the spatial change rate calculated from the corrected trend value with the distance to be predicted to generate the absolute settlement, a closed-loop logic is formed from stability judgment to trend correction and then to spatial extension. While ensuring the economy of measurement, it improves the accuracy and adaptability of melting settlement measurement in blank areas of highway subgrade. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0018] Figure 1 This is a partial flowchart of the method for measuring the thaw settlement of highway subgrade in permafrost regions according to the present invention.

[0019] Figure 2 This is a schematic diagram of another part of the method for measuring the thaw settlement of highway subgrade in permafrost regions according to the present invention.

[0020] Figure 3 This is a schematic diagram of another part of the process for measuring the thaw settlement of highway subgrade in permafrost regions according to the present invention.

[0021] Figure 4 This is a schematic diagram illustrating the steps of the method for measuring the thaw settlement of highway subgrade in permafrost regions according to the present invention.

[0022] Figure 5 This is a schematic diagram of part of step S4 in the method for measuring the thaw settlement of highway subgrade in permafrost regions of the present invention;

[0023] Figure 6 This is a schematic diagram of part of step S42 in the method for measuring the thaw settlement of highway subgrade in permafrost regions of the present invention;

[0024] Figure 7 This is a schematic diagram of part of step S43 in the method for measuring the thaw settlement of highway subgrade in permafrost regions of the present invention;

[0025] Figure 8 This is a schematic diagram of part of step S3 in the method for measuring the thaw settlement of highway subgrade in permafrost regions according to the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0028] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, a method for measuring the thaw settlement of highway subgrade in permafrost areas is provided. In one embodiment, the method includes:

[0030] S1. Obtain the roadbed area to be measured, and obtain multiple measurement directions located within the roadbed area to be measured. Set multiple measurement nodes evenly in each measurement direction to form a node sequence for each measurement direction, and obtain each blank measurement area located within the roadbed area to be measured and on the extension section of each measurement direction.

[0031] S2. Obtain the interval duration, and obtain the first time interval that is separated from the current time interval and the second time interval that is separated from the current time interval twice the interval duration. Obtain the first roadbed height sequence of each node sequence at the first time interval, obtain the second roadbed height sequence of each node sequence at the second time interval, and obtain the current roadbed height sequence of each node sequence at the current time interval.

[0032] S3. Obtain the current trend value based on the current roadbed height sequence of each node sequence, obtain the first historical trend value based on the first roadbed height sequence of each node sequence, obtain the second historical trend value based on the second roadbed height sequence of each node sequence, obtain the first difference based on the current trend value and the first historical trend value, and obtain the second difference based on the first historical trend value and the second historical trend value.

[0033] S4. If both the first difference and the second difference are less than the preset threshold, then obtain the blank measurement area in each measurement direction, and obtain the measurement results of each blank measurement area according to the current roadbed height sequence of each node sequence.

[0034] In this embodiment, it should be noted that in S1, a measurement framework covering the roadbed is established. First, the roadbed area is divided and the measurement directions are determined. The area of ​​the roadbed to be monitored is first clearly defined (e.g., the section from K10+500 to K12+000 of a permafrost highway). Based on the highway alignment and geological characteristics, several parallel longitudinal measurement directions are divided. These directions are typically set along the roadbed centerline, shoulder, or specific geological boundary lines, forming a "measurement zone" that runs through the permafrost zone. For example, in sections where steep slopes meet river valleys, the measurement directions need to consider both areas of abrupt topographic changes (such as thawing-sensitive zones at the toe of slopes) and relatively stable areas (such as bedrock outcrops) to capture the settlement differences between different geological units.

[0035] Secondly, node placement and blank area identification are carried out. Measurement nodes are evenly placed at preset intervals (e.g., 100 meters) in each measurement direction, forming a linear node sequence. Due to practical limitations, nodes cannot be placed in certain areas (such as under bridges and culverts, in vegetation protection areas, or in high-water-content ice wedge areas), forming "blank measurement areas." These blank areas are usually located in the extensions of the node sequence. For example, if the node sequence in a certain measurement direction terminates at the starting point of a culvert structure, the area covered by the culvert is marked as a blank area; or when the node sequence crosses a marsh vegetation zone, continuous blank sections are formed in the center of the wetland due to construction limitations.

[0036] Further, taking a section of a permafrost highway traversing a glacial lake sedimentary basin as an example, three measurement directions are set along the longitudinal direction of the roadbed, corresponding to the left shoulder, the roadbed centerline, and the right shoulder, respectively. The centerline direction needs to avoid the area where thermal pipelines are laid, hence a slight offset. Nodes are deployed in the section from K11+200 to K11+400 of the centerline. Due to the presence of a thick layer of underground ice wedges, construction machinery cannot enter, and nodes can only be deployed on both sides of the ice wedge area (K11+150 and K11+450), resulting in a 200-meter blank area in the ice wedge area. In the right shoulder direction, at K11+600, due to the requirement of protecting the original forest land, a circular blank area with a diameter of 50 meters is formed. Finally, a blank measurement area is formed. When the node sequence terminates at the slope (such as the endpoint K12+000 in the left shoulder direction), the potential slip zone on its outer side is defined as a blank measurement area on the extension section, and its settlement trend needs to be measured through prediction.

[0037] In S2, a multi-temporal roadbed state is constructed to capture the dynamic evolution characteristics of permafrost settlement. Specifically, a basic interval is first set (such as a temperature fluctuation cycle or the typical duration of a freeze-thaw cycle), establishing three key monitoring moments: the current moment (the latest monitoring time), the first moment (a historical node one interval back from the current moment), and the second moment (an even earlier historical node two intervals back from the current moment). This forms a progressive temporal chain (second moment → first moment → current moment), enabling the tracking of the continuity of settlement trends. For example, during the spring permafrost thawing period, if the interval is set to 48 hours, the current moment represents the thawing acceleration period, the first moment represents the initial thawing period, and the second moment represents the residual permafrost stabilization period.

[0038] Furthermore, in each measurement direction, complete roadbed height sequences are acquired for the three time points mentioned above. The real-time height value of each measurement node at the current time is extracted to form the current roadbed height sequence of the node sequence. The archived height value of the same node sequence at the first time point is retrieved to generate the first roadbed height sequence. The historical height value at the second time point is traced back to construct the second roadbed height sequence. For example, if the node sequence in the centerline direction of a certain roadbed contains 5 measurement nodes, then 5 sets of height data are obtained at the three time points, forming three continuous spatial curves reflecting the settlement state at different times.

[0039] In S3, the stability of the settlement trend is dynamically determined through comparative analysis of trend values ​​over multiple time periods. First, the current trend value is extracted. Based on the height sequence of all measured nodes at the current moment, the height changes between adjacent nodes are calculated and accumulated to generate a global value reflecting the latest settlement tendency. For example, if most nodes in the sequence show continuous subsidence, the accumulated value will show a significant negative trend. Simultaneously, historical trend values ​​are extracted. Using the same method, the height sequence trend values ​​for the first time period (time interval ago) and the second time period (twice the time interval ago) are calculated to obtain the first historical trend value and the second historical trend value.

[0040] Furthermore, the magnitude of trend fluctuations is quantified. The absolute deviation between the current trend value and the first historical trend value is calculated to reflect the degree of recent trend abrupt change (e.g., whether the downward trend has reversed within 24 hours). The absolute deviation between the first historical trend value and the second historical trend value is calculated to characterize the stability of the medium-term trend (e.g., whether the trend has continued to strengthen over the past 48 hours). The difference design avoids sign interference (e.g., upward and downward movements cancel each other out), focusing on the absolute strength of trend changes.

[0041] Furthermore, the preset threshold represents the acceptable tolerance for trend fluctuations. If both the first difference (short-term fluctuation) and the second difference (medium-term fluctuation) are less than the threshold, it indicates that the subsidence trend from the second moment to the current moment is continuous and stable (such as continuous linear subsidence or uplift). At this time, it is determined that the current environment meets the prediction conditions; otherwise, it indicates a risk (such as a sudden frost heave interrupting the subsidence), and the prediction is interrupted to avoid amplifying the error.

[0042] The preset thresholds are not generated using fixed values, but rather through a dynamic mapping between the roadbed geological archive and the characteristics of the permafrost environment. First, the preset thresholds are matched with geological parameters, directly correlated with the ice content of the permafrost and soil type (e.g., peat / gravel). For example, a strict threshold (e.g., 5) is used in high-ice-content permafrost areas (>30% ice wedge), while a more lenient threshold (e.g., 8) is used in low-ice-content areas. Due to the high thermal sensitivity of peat layer sections, the threshold is further compressed by 20%. Second, the preset thresholds are adaptively adjusted in stages. During periods of active permafrost thawing (e.g., spring and summer), the threshold is automatically tightened by 30% to improve sensitivity; during stable periods (winter), the threshold is relaxed by 20%. Simultaneously, the preset thresholds have a real-time feedback learning mechanism. When the deviation between the predicted result and the actual measured value (e.g., subsequent borehole verification) is less than 5% for three consecutive times, the system determines that the current threshold is too strict and automatically relaxes it by 1.1 times. When the difference exceeds the threshold twice consecutively, causing prediction interruption, a 0.9-fold iteration tightening of the threshold is triggered to improve sensitivity.

[0043] In S4, the adaptive execution phase for blank area prediction is initiated, triggered only after the settlement trend passes the stability test. First, the current trend value calculated in S3 is directly used as the first predicted trend value for the blank area. This value reflects the overall settlement tendency based on the current node sequence (e.g., continuous subsidence along the entire line). Second, the first difference (deviation between the current trend and the first time point) and the second difference (deviation between the first and second time point trends) from S3 are combined to analyze whether the historical fluctuation directions are consistent. Finally, if both are in the same direction (e.g., both show accelerated settlement), the first predicted trend value is enhanced and corrected in the same direction (e.g., increasing the predicted settlement magnitude); if they are in opposite directions (e.g., the difference shows acceleration followed by deceleration), the original value is retained without correction to avoid interfering with the reliability of the latest trend.

[0044] Furthermore, spatial extension settlement is extrapolated (S43). The latest measured height of the last measurement point in the node sequence is used as the prediction starting point (e.g., the height of the slope's starting point). The rate of change per unit distance in the blank area (e.g., settlement per meter) is calculated based on the corrected second prediction trend value. Combining the spatial distance between the blank area and the last node (e.g., a slope extension of 50 meters), the total change is extrapolated by multiplying the rate of change by the distance. Finally, the absolute settlement height of the blank area is obtained by superimposing the starting height. The entire S4, through the dual guarantee of trend correction and spatial extrapolation, achieves accurate prediction of settlement in the blank area under a sparse node layout.

[0045] In summary, in the method for measuring roadbed thaw settlement in permafrost regions, firstly, by extracting three time-series roadbed height sequences—the current time, the time interval before, and twice the time interval before—and calculating the corresponding trend values ​​and trend differences, a dynamic discrimination mechanism for trend stability is constructed. Prediction is triggered only when both short-term (first difference) and medium-term (second difference) trend fluctuations are below a threshold, fundamentally avoiding the risk of forced extrapolation caused by sudden refreezing or accelerated thaw settlement in permafrost. Furthermore, combining the zonal characteristics of the measurement direction with a trend value correction strategy, in the prediction stage, the current trend value is used as the basis, and the trend difference is adjusted accordingly. The directional dynamic correction (enhancing adjustment for unidirectional fluctuations and maintaining the original value for reverse fluctuations) not only utilizes the regularity of zonal settlement but also offsets the interference of local geological heterogeneity (such as ice wedge abrupt changes and single-point collapses) through differential feedback, avoiding misjudging short-term fluctuations as overall trends. Furthermore, by using the measured height of the end node as the starting point and combining the spatial change rate calculated from the corrected trend value with the distance to be predicted to generate the absolute settlement, a closed-loop logic is formed from stability judgment to trend correction and then to spatial extension. This improves the accuracy and adaptability of melting settlement measurement in blank areas of highway subgrade while ensuring measurement economy.

[0046] like Figure 5 As shown, in one embodiment, S4, obtaining the measurement results of each blank measurement area based on the current roadbed height sequence of each node sequence includes:

[0047] S41. Use the current trend value in each measurement direction as the first predicted trend value for each blank measurement area;

[0048] S42. Correct the first predicted trend value based on the first difference and the second difference to obtain the second predicted trend value;

[0049] S43. Obtain the last current subgrade height data in the current subgrade height sequence of each node sequence and use it as the starting subgrade height data. Obtain the measurement results of each blank measurement area based on the second predicted trend value of each blank measurement area and the starting subgrade height data.

[0050] In this embodiment, it should be noted that in S41, the current trend value calculated in step S3 (reflecting the latest settlement tendency of the entire node sequence) is directly used as the first predicted trend value of the blank area to establish an initial prediction benchmark. For example, if the current trend value in the direction of a roadbed centerline is continuous subsidence (negative), the subsidence trend is mapped to the blank area covered by the culvert to form a preliminary prediction direction.

[0051] In S42, the first predicted trend value is adaptively adjusted by combining the directional analysis of the first difference (the trend deviation between the current time and the first moment) and the second difference (the trend deviation between the first and second moments).

[0052] If both show accelerated settlement (e.g., the first difference is positive and the second difference is also positive), then the first predicted trend value is corrected in the same direction (e.g., the settlement amplitude is increased) to match the trend continuity.

[0053] If the two values ​​are in opposite directions (e.g., the first difference shows acceleration and the second difference shows deceleration), it indicates that there is a risk of trend reversal. In this case, the original forecast value should be retained without modification to avoid introducing noise.

[0054] For example, when the nodes on both sides of the ice wedge show that the recent melting and subsidence has accelerated and continued to intensify in the medium term (the two differences are in the same direction), the predicted subsidence value of the blank area is automatically increased; if the recent acceleration has been accelerated but the medium term has decelerated (in the opposite direction), the initial predicted value is maintained.

[0055] In S43, the measured height at the end of the node sequence (such as the starting point of the slope) is used as the starting point. The rate of change per unit distance in the blank area (such as the amount of settlement per meter) is calculated by using the corrected second predicted trend value. Then, the total change is calculated by combining the spatial distance between the blank area and the last node.

[0056] like Figure 6 As shown, in one embodiment, step S42, correcting the first predicted trend value based on the first difference and the second difference to obtain the second predicted trend value, includes:

[0057] S421. When the trend fluctuation direction reflected by the first difference and the second difference is the same, the first predicted trend value is compensated in the same direction according to the fluctuation direction, and the second predicted trend value is obtained.

[0058] S422. When the trend fluctuations reflected by the first difference and the second difference are opposite, the first predicted trend value is used as the second predicted trend value.

[0059] In this embodiment, it should be noted that in S421, when the first difference (reflecting a recent trend change) and the second difference (reflecting a medium-term trend fluctuation) are in the same direction (e.g., both show continuous accelerated settlement or uplift), the system determines that the trend exhibits a continuous strengthening characteristic. At this time, based on the potential extensibility of permafrost thawing or refreezing, the first predicted trend value is compensated and corrected in the same direction.

[0060] For example, if the current trend value is downward and both differences point to accelerated downward (i.e., the difference calculation results are both positive), then the predicted value of the downward magnitude is increased to match the risk of increased subsidence caused by the lag in heat conduction in permafrost areas (such as the scenario of continuous melting of underground ice wedges).

[0061] In S422, when the first and second differences show opposite directions (e.g., the first difference indicates accelerated subsidence while the second difference indicates historical deceleration), it indicates instability or reversal signals in the trend evolution (e.g., local frost heave disturbance or pause in ice melting). To avoid amplifying errors, the system abandons correction and directly uses the first predicted trend value as the final output. For example, if the current trend value is subsidence, but the difference shows an earlier deceleration (possibly due to a brief refreezing caused by a cold wave), the freeze correction operation can prevent local disturbances from being misjudged as long-term trends (e.g., abnormal phase change of the ice-water mixture beneath vegetation cover).

[0062] like Figure 7 As shown, in one embodiment, S43, obtaining the measurement results of each blank measurement area based on the second predicted trend value and the initial roadbed height data of each blank measurement area includes:

[0063] S431. Obtain the distance between the blank measurement region of each node sequence and each node sequence and use it as the distance to be predicted;

[0064] S432. Obtain the rate of change of each blank measurement area based on the position range of each node sequence and the second predicted trend value of each blank measurement area.

[0065] S433. Obtain the change amount based on the change rate of each blank measurement area and the distance to be predicted, and obtain the measurement results of each blank measurement area based on the change amount and the initial roadbed height data.

[0066] In this embodiment, it should be noted that in S431, the spatial extension distance of the blank measurement area relative to the end of the node sequence is obtained as a geographical basis for the settlement estimation. For example, in the blank slip zone of the roadbed slope extension section, the straight-line distance from its center point to the end node of the shoulder needs to be measured; in the continuous blank area covered by culverts, the extension distance from the culvert entrance to the nearest node is calculated.

[0067] In S432, based on the second predicted trend value and the spatial span of the node sequence, the macro trend quantity is converted into a rate of change per unit distance in the blank area (such as millimeters of settlement per kilometer). For example, if the total length of the node sequence in a certain shoulder direction is 500 meters, and the corrected trend value indicates strong subsidence, the rate of change of height per meter in that direction will be calculated to reflect the linear diffusion law of permafrost thawing along the road direction.

[0068] In S433, based on the starting point height (measured value at the end node) and the distance to be predicted, the total change in height is calculated by multiplying the rate of change by the distance, generating the final settlement height of the blank area. For example, if the blank section below the vegetation cover area is 300 meters from the end node, and the rate of change is 2 centimeters of settlement per 100 meters, then a total settlement of 6 centimeters is estimated, which is then superimposed on the starting point height to output the absolute elevation. This ensures that the prediction results have both spatial continuity (based on the measured starting point) and trend guidance (based on the corrected rate of change).

[0069] like Figure 8 As shown, in one implementation, obtaining the current trend value in S3 based on the current roadbed height sequence of each node sequence includes:

[0070] S31. Obtain the current change in the current roadbed height data of adjacent measurement nodes in the node sequence;

[0071] S32. Accumulate all current changes in the node sequence to obtain the current trend value.

[0072] In this embodiment, it should be noted that in S31, the node sequence along the measurement direction is traversed, and the difference in roadbed height between adjacent measurement nodes at the current time is calculated sequentially (such as the height difference between nodes A and B), generating a set of current changes that reflect the local settlement characteristics in that direction.

[0073] In S32, the current changes of all adjacent nodes in the node sequence are linearly superimposed (e.g., the sum of changes from A to B, B to C, and C to D) to generate the overall current trend value in that direction. This design converges scattered local fluctuations into a macro trend: for example, in the direction of the roadbed centerline, if the sum of small subsidence differences between most nodes forms a significant negative value, it indicates that the settlement trend is stable; while outliers from single-point collapses are diluted by data from other stable nodes during accumulation, avoiding misjudging local geological heterogeneity (such as the melting of isolated ice wedges) as a trend along the entire line.

[0074] It should also be noted that both the first and second historical trend values ​​can be obtained using the same method as obtaining the current trend value.

[0075] In one implementation, obtaining the first difference between the current trend value and the first historical trend value in S3 includes:

[0076] Subtract the first historical trend value from the current trend value and take the absolute value to obtain the first difference.

[0077] In this embodiment, it should be noted that the first difference quantifies the intensity of short-term trend fluctuations by calculating the absolute deviation between the current trend value and the first historical trend value. At the same time, taking the absolute value ensures that the result is always positive (e.g., the absolute value of the deviation between -5 and +3 is 8), avoiding erroneous conclusions when comparing the sign difference with a preset threshold.

[0078] It should also be noted that the second difference can be obtained using the same method as the first difference.

[0079] A system for measuring the thaw settlement of highway subgrade in permafrost regions is also provided. The system includes:

[0080] The first data measurement module is used to acquire the roadbed area to be measured, acquire multiple measurement directions located within the roadbed area to be measured, uniformly set multiple measurement nodes in each measurement direction to form a node sequence in each measurement direction, and acquire each blank measurement area located within the roadbed area to be measured and on the extension section in each measurement direction.

[0081] The second data measurement module is used to obtain the interval duration, and to obtain the first moment that is separated from the current moment by the interval duration and the second moment that is separated from the current moment by twice the interval duration, and to obtain the first roadbed height sequence of each node sequence at the first moment, the second roadbed height sequence of each node sequence at the second moment, and the current roadbed height sequence of each node sequence at the current moment.

[0082] The data processing module is used to obtain the current trend value based on the current roadbed height sequence of each node sequence, obtain the first historical trend value based on the first roadbed height sequence of each node sequence, obtain the second historical trend value based on the second roadbed height sequence of each node sequence, obtain the first difference based on the current trend value and the first historical trend value, and obtain the second difference based on the first historical trend value and the second historical trend value.

[0083] The predictive measurement module is used to obtain blank measurement areas in each measurement direction if both the first difference and the second difference are less than a preset threshold, and to obtain the measurement results of each blank measurement area according to the current roadbed height sequence of each node sequence.

[0084] In one embodiment, the predictive measurement module is further configured to: use the current trend value in each measurement direction as the first predicted trend value for each blank measurement area; correct the first predicted trend value according to the first difference and the second difference to obtain the second predicted trend value; obtain the last current roadbed height data in the current roadbed height sequence of each node sequence and use it as the starting roadbed height data; and obtain the measurement results of each blank measurement area according to the second predicted trend value and the starting roadbed height data of each blank measurement area.

[0085] In one embodiment, the prediction measurement module is further configured to: when the trend fluctuation directions reflected by the first difference and the second difference are the same, compensate the first predicted trend value in the same direction according to the fluctuation direction, and obtain the second predicted trend value; when the trend fluctuation directions reflected by the first difference and the second difference are opposite, use the first predicted trend value as the second predicted trend value.

[0086] In one embodiment, the prediction measurement module is further configured to: obtain the distance between the blank measurement area of ​​each node sequence and each node sequence and use it as the distance to be predicted; obtain the rate of change of each blank measurement area based on the location range of each node sequence and the second prediction trend value of each blank measurement area; obtain the amount of change based on the rate of change of each blank measurement area and the distance to be predicted, and obtain the measurement result of each blank measurement area based on the amount of change and the initial roadbed height data.

[0087] In this embodiment, it should be noted that the specific operation method of the above-mentioned roadbed thaw settlement measurement system for highways in permafrost areas has been described in detail in the embodiments of the relevant roadbed thaw settlement measurement method for highways in permafrost areas, and will not be elaborated here.

[0088] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0089] It should also be noted that the combination of one or more letters “A, B, C, D, E” described in the above specific embodiments can represent different plant names or varieties, and the same combination of letters in different embodiments can represent different plant names or varieties.

[0090] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0091] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for measuring the thaw settlement of highway subgrade in permafrost areas, characterized in that, include: Obtain the roadbed area to be measured, and obtain multiple measurement directions within the roadbed area to be measured. Set multiple measurement nodes evenly in each measurement direction to form a node sequence for each measurement direction. Obtain each blank measurement area within the roadbed area to be measured and on the extension of each measurement direction. Obtain the interval duration, and obtain the first time interval that is separated from the current time interval and the second time interval that is separated from the current time interval twice the current time interval. Obtain the first roadbed height sequence of each node sequence at the first time interval, obtain the second roadbed height sequence of each node sequence at the second time interval, and obtain the current roadbed height sequence of each node sequence at the current time interval. The current trend value is obtained based on the current roadbed height sequence of each node sequence, the first historical trend value is obtained based on the first roadbed height sequence of each node sequence, the second historical trend value is obtained based on the second roadbed height sequence of each node sequence, the first difference is obtained based on the current trend value and the first historical trend value, and the second difference is obtained based on the first historical trend value and the second historical trend value. If both the first difference and the second difference are less than the preset threshold, then the blank measurement areas in each measurement direction are obtained, and the measurement results of each blank measurement area are obtained according to the current roadbed height sequence of each node sequence.

2. The method for measuring the thaw settlement of highway subgrade in permafrost areas according to claim 1, characterized in that, The process of obtaining the measurement results for each blank measurement area based on the current roadbed height sequence of each node sequence includes: The current trend value in each measurement direction is used as the first predicted trend value for each blank measurement area; The first predicted trend value is corrected based on the first difference and the second difference to obtain the second predicted trend value; The last current subgrade height data in the current subgrade height sequence of each node sequence is obtained and used as the starting subgrade height data. The measurement results of each blank measurement area are obtained based on the second predicted trend value of each blank measurement area and the starting subgrade height data.

3. The method for measuring the thaw settlement of highway subgrade in permafrost areas according to claim 2, characterized in that, The step of correcting the first predicted trend value based on the first difference and the second difference to obtain the second predicted trend value includes: When the first difference and the second difference reflect the same trend fluctuation direction, the first predicted trend value is compensated in the same direction according to the fluctuation direction, and the second predicted trend value is obtained. When the trend fluctuations reflected by the first difference and the second difference are opposite in direction, the first predicted trend value is used as the second predicted trend value.

4. The method for measuring the thaw settlement of highway subgrade in permafrost areas according to claim 2, characterized in that, The process of obtaining the measurement results for each blank measurement area based on the second predicted trend value and the initial roadbed height data of each blank measurement area includes: Obtain the distance between the blank measurement region of each node sequence and each node sequence and use it as the distance to be predicted; The rate of change of each blank measurement area is obtained based on the position range of each node sequence and the second predicted trend value of each blank measurement area. The change amount is obtained based on the rate of change of each blank measurement area and the distance to be predicted, and the measurement results of each blank measurement area are obtained based on the change amount and the initial roadbed height data.

5. The method for measuring the thaw settlement of highway subgrade in permafrost areas according to claim 1, characterized in that, The process of obtaining the current trend value based on the current roadbed height sequence of each node sequence includes: Obtain the current change in the current roadbed height data of adjacent measurement nodes in the node sequence; The current trend value is obtained by summing up all the current changes in the node sequence.

6. The method for measuring the thaw settlement of highway subgrade in permafrost areas according to claim 1, characterized in that, The step of obtaining the first difference based on the current trend value and the first historical trend value includes: Subtract the first historical trend value from the current trend value and take the absolute value to obtain the first difference.

7. A system for measuring the thaw settlement of highway subgrade in permafrost areas, characterized in that, The system includes: The first data measurement module is used to acquire the roadbed area to be measured, acquire multiple measurement directions located within the roadbed area to be measured, uniformly set multiple measurement nodes in each measurement direction to form a node sequence in each measurement direction, and acquire each blank measurement area located within the roadbed area to be measured and on the extension section in each measurement direction. The second data measurement module is used to obtain the interval duration, and to obtain the first moment that is separated from the current moment by the interval duration and the second moment that is separated from the current moment by twice the interval duration, and to obtain the first roadbed height sequence of each node sequence at the first moment, the second roadbed height sequence of each node sequence at the second moment, and the current roadbed height sequence of each node sequence at the current moment. The data processing module is used to obtain the current trend value based on the current roadbed height sequence of each node sequence, obtain the first historical trend value based on the first roadbed height sequence of each node sequence, obtain the second historical trend value based on the second roadbed height sequence of each node sequence, obtain the first difference based on the current trend value and the first historical trend value, and obtain the second difference based on the first historical trend value and the second historical trend value. The predictive measurement module is used to obtain blank measurement areas in each measurement direction if both the first difference and the second difference are less than a preset threshold, and to obtain the measurement results of each blank measurement area according to the current roadbed height sequence of each node sequence.

8. The roadbed thaw settlement measurement system for highways in permafrost areas according to claim 7, characterized in that, The predictive measurement module is also used to: use the current trend value in each measurement direction as the first predicted trend value for each blank measurement area; The first predicted trend value is corrected based on the first difference and the second difference to obtain the second predicted trend value; The last current subgrade height data in the current subgrade height sequence of each node sequence is obtained and used as the starting subgrade height data. The measurement results of each blank measurement area are obtained based on the second predicted trend value of each blank measurement area and the starting subgrade height data.

9. The roadbed thaw settlement measurement system for highways in permafrost areas according to claim 7, characterized in that, The predictive measurement module is also used for: When the first difference and the second difference reflect the same trend fluctuation direction, the first predicted trend value is compensated in the same direction according to the fluctuation direction, and the second predicted trend value is obtained. When the trend fluctuations reflected by the first difference and the second difference are opposite in direction, the first predicted trend value is used as the second predicted trend value.

10. The roadbed thaw settlement measurement system for highways in permafrost areas according to claim 7, characterized in that, The predictive measurement module is also used for: Obtain the distance between the blank measurement region of each node sequence and each node sequence and use it as the distance to be predicted; The rate of change of each blank measurement area is obtained based on the position range of each node sequence and the second predicted trend value of each blank measurement area. The change amount is obtained based on the rate of change of each blank measurement area and the distance to be predicted, and the measurement results of each blank measurement area are obtained based on the change amount and the initial roadbed height data.

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