Ground subsidence monitoring method and system based on weak grating array monitoring

Abstract

The invention relates to the technical field of building construction, in particular to a land subsidence monitoring method and system based on weak grating array monitoring, and the method comprises the steps: obtaining real-time strain and subsidence; determining a first temporary area; determining a second temporary area; acquiring the width of a bump crack; adjusting a preset synchronization degree threshold value; correcting a settling volume threshold value; and sending out an abnormal prompt. Through the high-precision monitoring capability of the weak grating array, real-time dynamic tracking of ground subsidence in the subway construction process is achieved, the recognition precision of abnormal subsidence is improved, the mode of step-by-step screening and dynamic threshold value adjustment is adopted, misjudgment can be effectively reduced, and the recognition precision of abnormal subsidence is improved in combination with bulge crack width change analysis. The settlement trend and potential risks can be more accurately judged, false alarms caused by stratum disturbance or construction vibration are reduced, the stability of subway construction and the surrounding environment is ensured, and the problem of low monitoring result accuracy caused by dependence on static and single monitoring data is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and in particular to a ground subsidence monitoring method and system based on weak grating array monitoring. Background Art

[0002] With the rapid development of urban subway construction, shield construction has become a commonly used construction method in underground projects. However, during the shield construction process, due to changes in soil pressure and construction technology factors, ground subsidence and deformation may occur, and may even cause safety hazards to surrounding buildings or infrastructure. These phenomena are often difficult to detect and accurately evaluate in time through traditional monitoring methods, affecting the safety and stability of construction. Especially in densely populated urban areas, the impact of shield construction on the environment is more prominent. How to efficiently and in real time monitor and warn of ground subsidence and bulging phenomena has become a technical problem that needs to be solved urgently.

[0003] Patent document with publication number CN103363954A discloses a ground subsidence monitoring system, which includes: a groundwater level monitoring unit for real-time data collection and monitoring of the groundwater level at each monitoring point set in the monitoring area, and an underground stratum monitoring unit for real-time data collection and monitoring of the compression and expansion of each underground soil layer at each monitoring point. The groundwater level monitoring unit and the underground stratum monitoring unit of each monitoring point output the collected data to the data collection unit for storage and organization, and the data collection unit then outputs the data to the data processing unit for analysis and real-time monitoring of the ground subsidence in the area.

[0004] It can be seen that the ground subsidence monitoring system has the following problems: the system first stores and organizes the data and then transmits it to the data processing unit for analysis, which will cause a lag in data processing and make it impossible to achieve real-time dynamic monitoring and rapid response; the system relies too much on changes in groundwater levels and soil layers to judge the subsidence situation, resulting in a decrease in the accuracy of the monitoring results. Summary of the invention

[0005] To this end, the present invention provides a ground subsidence monitoring method and system based on weak grating array monitoring, which is used to overcome the problem of low accuracy of monitoring results caused by reliance on static and single monitoring data in the prior art through real-time monitoring and dynamic adjustment of monitoring accuracy.

[0006] To achieve the above object, on the one hand, the present invention provides a ground subsidence monitoring method based on weak grating array monitoring, comprising: Obtain the real-time strain value and real-time ground settlement of each weak grating array acquisition area during subway shield construction; Determine a plurality of first temporary areas according to the real-time ground subsidence and a preset subsidence threshold; Determine a plurality of second temporary areas according to the real-time ground settlement amount, the real-time strain value and a preset synchronization threshold of each of the first temporary areas; Obtaining a real-time crack width at each bulge in the second temporary area according to the real-time strain values ​​in all the second temporary areas; Adjust the preset synchronization threshold according to the real-time crack width within the preset adjustment time to form an adjusted synchronization threshold; Correcting the preset settlement threshold according to the number of the second temporary areas determined based on the adjustment synchronization threshold within a preset correction time period to form a corrected settlement threshold; Determine a number of abnormal settlement areas according to the real-time crack width obtained based on the modified settlement threshold within a preset determination time period; An abnormal prompt is issued according to the abnormal settlement area.

[0007] Further, determining a plurality of first temporary areas according to the real-time ground subsidence and a preset subsidence threshold includes: When the real-time ground settlement amount is greater than the preset settlement amount threshold, the weak grating array acquisition area is determined to be the first temporary area to determine a plurality of first temporary areas.

[0008] Further, determining a plurality of second temporary areas according to the real-time ground settlement amount, the real-time strain value and a preset synchronization threshold of each of the first temporary areas includes: Calculate the standard deviation of all the real-time ground settlement amounts within a preset synchronous calculation time to form a settlement fluctuation value; Calculating the standard deviation of all the real-time strain values ​​within the preset synchronous calculation time to form a strain fluctuation value; A plurality of second temporary areas are determined according to the settlement fluctuation value, the strain fluctuation value and the preset synchronization threshold.

[0009] Further, determining a plurality of second temporary areas according to the settlement fluctuation value, the strain fluctuation value and the preset synchronization threshold comprises: Draw a change curve of the settlement fluctuation value within the preset synchronous calculation time to form a settlement fluctuation curve; Drawing a variation curve of the strain fluctuation value within the preset synchronous calculation time to form a strain fluctuation curve; Calculating the cosine similarity of the settlement fluctuation curve and the strain fluctuation curve to form synchronization; When the synchronization degree is less than the preset synchronization degree threshold, the first temporary area is determined to be the second temporary area, so as to determine a plurality of second temporary areas.

[0010] Further, obtaining the real-time crack width of each bulge in the second temporary area according to the real-time strain values ​​in all the second temporary areas includes: Calculating the standard deviation of all the real-time strain values ​​to form a strain distribution value; When the strain distribution value is greater than a preset strain distribution threshold, the real-time crack width at each bulge in the second temporary area is obtained according to the real-time strain values ​​of any two adjacent second temporary areas.

[0011] Further, obtaining the real-time crack width of each bulge in the second temporary area according to the real-time strain values ​​of any two adjacent second temporary areas includes: Obtaining the distance between the two second temporary areas; Calculating a difference between the real-time strain values ​​of the two second temporary areas to form a strain difference; Calculating a ratio of the strain difference to the distance to form a strain gradient; When the strain gradient is greater than a preset gradient threshold, determining the midpoint of the two second temporary areas as the midpoint of the bulge to form the bulge midpoint; Get the width of all cracks in a circular area with the midpoint of the bulge as the circle point and the preset bulge length as the radius; The average of all said widths is calculated to form the real-time crack width.

[0012] Further, adjusting the preset synchronization threshold according to the real-time crack width within the preset adjustment time to form the adjustment synchronization threshold includes: Calculating the standard deviation of the real-time crack width to form a first width fluctuation value; When the first width fluctuation value is greater than a preset first width fluctuation threshold, the preset synchronization threshold is reduced according to a relative deviation between the crack width fluctuation value and the preset width fluctuation threshold and a preset adjustment coefficient to form an adjusted synchronization threshold.

[0013] Further, the preset settlement amount threshold is corrected according to the number of the second temporary areas determined based on the adjustment synchronization threshold within a preset correction time period to form a corrected settlement amount threshold, which includes: Calculating the standard deviation of the quantity in the second temporary area to form a quantity fluctuation value; When the quantity fluctuation value is greater than a preset quantity fluctuation threshold, a relative deviation between the quantity fluctuation value and the preset quantity fluctuation threshold is calculated to form a quantity fluctuation deviation; When the quantity fluctuation deviation is greater than the preset fluctuation deviation threshold, the preset settlement amount threshold is reduced according to the relative deviation between the quantity fluctuation deviation and the preset fluctuation deviation threshold and a preset correction coefficient to form a corrected settlement amount threshold.

[0014] Further, determining a number of abnormal settlement areas according to the real-time crack width obtained based on the modified settlement threshold within a preset determination time period includes: Calculating the standard deviation of the real-time crack width to form a second width fluctuation value; When the second width fluctuation value is greater than a preset second width fluctuation threshold, the corresponding circular area is determined to be the abnormal settlement area, so as to determine a plurality of abnormal settlement areas.

[0015] On the other hand, the present invention also provides a ground subsidence monitoring system based on weak grating array monitoring, comprising: The first acquisition module is used to obtain the real-time strain value and real-time ground settlement of each weak grating array acquisition area during the subway shield construction process; A first determination module, connected to the first acquisition module, for determining a plurality of first temporary areas according to the real-time ground subsidence and a preset subsidence threshold; A second determination module, which is connected to the first acquisition module and the first determination module respectively, and is used to determine a plurality of second temporary areas according to the real-time ground settlement amount, the real-time strain value and a preset synchronization threshold of each of the first temporary areas; A second acquisition module, connected to the second determination module, for acquiring a real-time crack width at each bulge in the second temporary area according to the real-time strain values ​​in all the second temporary areas; an adjustment module, which is connected to the second determination module and the second acquisition module respectively, and is used to adjust the preset synchronization threshold according to the real-time crack width within a preset adjustment time period to form an adjusted synchronization threshold; a correction module, which is connected to the first determination module, the adjustment module and the second determination module respectively, and is used to correct the preset settlement amount threshold according to the number of the second temporary areas determined based on the adjustment synchronization threshold within a preset correction time period to form a corrected settlement amount threshold; a third determination module, which is connected to the correction module and the second acquisition module respectively, and is used to determine a number of abnormal settlement areas according to the real-time crack width obtained based on the correction settlement threshold within a preset determination time period; A prompt module is connected to the third determination module and is used to issue an abnormal prompt according to the abnormal settlement area.

[0016] Compared with the prior art, the beneficial effect of the present invention lies in that, through the high-precision monitoring capability of the weak grating array, real-time and dynamic tracking of ground subsidence during subway construction is achieved, the recognition accuracy of abnormal subsidence is improved, and the method of step-by-step screening and dynamic adjustment of thresholds can effectively reduce misjudgment and improve the adaptability of the monitoring system. At the same time, combined with the analysis of changes in the width of bulge cracks, it can more accurately judge the subsidence trend and potential risks, reduce false alarms caused by stratum disturbance or construction vibration, thereby optimizing construction safety management, reducing subsidence risks, and ensuring the stability of subway construction and the surrounding environment, effectively solving the problem of low accuracy of monitoring results caused by reliance on static and single monitoring data.

[0017] Furthermore, through layered screening and dynamic adjustment of thresholds, the misjudgment rate is effectively reduced, making anomaly detection more reliable. Weak grating array monitoring technology is used to ensure the accuracy of data collection, and by monitoring the width of cracks at the bulge, fine-grained analysis of stratum disturbance is achieved, which can promptly detect hidden dangers caused by construction vibration. In addition, the automated monitoring process reduces the cost of manual inspections, improves the real-time nature of early warnings, and helps to ensure the long-term stability of subway structures and surrounding buildings.

[0018] Furthermore, by calculating the standard deviation to analyze the fluctuation of settlement and strain values, the ability to finely identify formation disturbances is improved, the screening of abnormal settlement areas is more accurate, and the interference of environmental noise and local abnormal data can be effectively reduced, and the stability and reliability of monitoring data can be improved. At the same time, by setting the preset synchronization threshold, it is ensured that the second temporary area selected can truly reflect the dynamic relationship between settlement and strain, thereby improving the accuracy of subsequent crack monitoring and abnormal warning.

[0019] Furthermore, by drawing settlement and strain fluctuation curves and calculating their synchronization, unstable areas of formation deformation can be effectively identified to avoid misjudgment that may be caused by single threshold judgment. At the same time, the cosine similarity analysis is used to improve the recognition accuracy and can more accurately screen out areas with poor synchronization, thereby optimizing the determination of abnormal settlement areas and improving the sensitivity and reliability of monitoring.

[0020] Furthermore, by calculating the strain distribution value through the standard deviation, it is possible to accurately identify areas with concentrated strain anomalies, and determine the crack width in combination with the strain value change trend in adjacent areas, thereby improving the accuracy of crack identification. It can not only effectively detect the bulging deformation of the formation, but also provide more fine-grained crack information for settlement monitoring, making the monitoring results more accurate and improving the safety and early warning capabilities during subway construction.

[0021] Furthermore, the formation position of the bulge is accurately located through strain gradient calculation to ensure the accuracy of bulge detection. At the same time, the crack width is analyzed with the bulge as the center, making the crack monitoring range more targeted and improving the reliability of crack width calculation. Combined with the deformation characteristics of the local area, it is possible to timely identify hidden dangers that may affect the safety of subway construction, providing more accurate data support for subsequent adjustments and corrections.

[0022] Furthermore, by dynamically adjusting the preset synchronization threshold, it is possible to flexibly respond to large fluctuations in crack width during construction, improve the sensitivity and accuracy of monitoring, ensure that slight changes in ground subsidence and deformation can be captured in a timely manner, and enhance the real-time response capability and monitoring accuracy of monitoring.

[0023] Furthermore, the settlement threshold is dynamically adjusted according to the fluctuation of the number of second temporary areas actually monitored, thereby improving the accuracy of settlement monitoring. When the abnormal fluctuation of settlement in the area increases, the threshold can be adjusted in time to prevent false alarms caused by overly strict thresholds, while ensuring accurate response to real abnormal settlement events, effectively improving the sensitivity and reliability of monitoring.

[0024] Furthermore, by analyzing the fluctuation of crack width, it is possible to accurately identify abnormal settlement areas caused by settlement, thereby quickly responding to potential construction risks. By setting a reasonable fluctuation threshold, overly sensitive detection can be avoided, ensuring the stability and efficiency of the monitoring system, while also issuing early warnings in a timely manner, providing an effective basis for subsequent construction adjustments.

[0025] Furthermore, through accurate real-time monitoring of ground subsidence, the monitoring parameters can be dynamically adjusted according to the actual data during the construction process, providing more refined anomaly detection. By adjusting the preset synchronization threshold and the preset settlement threshold, the system improves the accuracy and flexibility of monitoring, avoiding construction safety hazards caused by untimely detection of settlement problems. In addition, early identification of abnormal settlement areas can help relevant personnel take quick measures to effectively reduce construction risks and improve construction safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flow chart of the ground subsidence monitoring method based on weak grating array monitoring in this embodiment; Figure 2 A decision logic diagram for determining the first temporary area in this embodiment; Figure 3 A decision logic diagram for determining the second temporary area in this embodiment; Figure 4 Schematic diagram of the ground subsidence monitoring system based on weak grating array monitoring in this embodiment. DETAILED DESCRIPTION

[0027] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0029] See also Figure 1 As shown, it is a flow chart of the ground subsidence monitoring method based on weak grating array monitoring in this embodiment; On the one hand, this embodiment provides a ground subsidence monitoring method based on weak grating array monitoring, including: Obtain the real-time strain value and real-time ground settlement of each weak grating array acquisition area during subway shield construction; Determine a plurality of first temporary areas according to the real-time ground subsidence and a preset subsidence threshold; Determine a plurality of second temporary areas according to the real-time ground settlement amount, the real-time strain value and a preset synchronization threshold of each of the first temporary areas; Obtaining a real-time crack width at each bulge in the second temporary area according to the real-time strain values ​​in all the second temporary areas; Adjust the preset synchronization threshold according to the real-time crack width within the preset adjustment time to form an adjusted synchronization threshold; Correcting the preset settlement threshold according to the number of the second temporary areas determined based on the adjustment synchronization threshold within a preset correction time period to form a corrected settlement threshold; Determine a number of abnormal settlement areas according to the real-time crack width obtained based on the modified settlement threshold within a preset determination time period; An abnormal prompt is issued according to the abnormal settlement area.

[0030] Among them, the weak grating array acquisition area refers to the specific surface area monitored by the weak grating array sensors deployed in the subway construction area. These sensors use fiber grating technology and can monitor the strain value and ground settlement in the area in real time. When the sensor is affected by ground settlement or deformation, the optical signal will change, reflecting the strain and settlement. The sensors are evenly distributed in the construction area in the form of a square grid to ensure that there are enough monitoring points in each acquisition area. This distribution method helps to provide more accurate and comprehensive ground settlement monitoring data, forming a dense monitoring network for real-time tracking and analysis of ground deformation.

[0031] Real-time strain value refers to the degree of deformation of the ground or structure under the action of external forces (such as construction vibration, soil settlement, etc.) monitored in real time by weak grating array sensors. The strain value reflects the deformation of the object and is usually expressed as the amount of deformation per unit length. The fiber grating sensor can accurately capture the strain of the ground or structure at different locations and convert it into real-time optical signal changes, thereby obtaining specific strain values.

[0032] Real-time ground settlement refers to the vertical displacement of the ground due to construction or other external forces monitored in real time by sensors. It indicates the degree of ground subsidence in a specific area and is an important parameter for measuring ground settlement or structural deformation. By monitoring the changes in the surrounding light signals, the sensor can obtain the vertical displacement of the ground in real time, thereby providing real-time data on ground settlement.

[0033] During shield construction, bulging is caused by ground disturbance caused by vibration. Its formation mechanism may involve over-excavation, uneven synchronous grouting, ground loosening or stress redistribution. The generation of cracks is the result of further development of bulging.

[0034] The preset settlement threshold refers to the benchmark value for judging whether the ground settlement is abnormal, which depends on the geological conditions, construction technology and safety standards of the construction area. It is usually between 5 mm and 30 mm. In this embodiment, it is set to 10 mm to enable timely detection of potential settlement risks.

[0035] The preset synchronization threshold is used to measure the correlation between the ground settlement and the strain value in each acquisition area. It depends on the sensitivity and error range of the monitoring system and is usually between 0.7-0.95. In this embodiment, it is set to 0.85 to ensure the accuracy and reliability of the monitoring data.

[0036] The preset adjustment time refers to the time used to observe the real-time crack width change before the preset synchronization threshold is adjusted. It depends on the construction speed and geological stability, and is usually between 1 hour and 24 hours. In this embodiment, it is set to 6 hours to quickly respond to changes in settlement trends.

[0037] The preset correction time refers to the time used to observe the change in the number of second temporary areas before correcting the settlement threshold, which depends on the evolution speed of ground settlement and is usually between 12 hours and 72 hours. In this embodiment, it is set to 24 hours to ensure the stability and adaptability of the threshold adjustment.

[0038] Preset determination time: refers to the monitoring time before the abnormal settlement area is finally determined, which depends on the engineering safety requirements and the time scale of settlement development. It is usually between 24 hours and 168 hours. In this embodiment, it is set to 48 hours to ensure the accuracy of abnormal determination and avoid misjudgment or delayed response.

[0039] Based on weak grating array sensing technology, by real-time monitoring of the strain values ​​and ground settlement of each collection area during subway construction, potential settlement abnormal settlement areas are gradually screened out. First, based on the real-time ground settlement and the preset threshold, the first temporary area that may have a settlement risk is preliminarily determined; then, combined with the preset synchronization threshold, the second temporary area that is more affected by the construction is further screened out, and the crack width at the bulge position is monitored. Then, the preset synchronization threshold is dynamically adjusted within the preset adjustment time to optimize the judgment standard, and the settlement threshold is corrected within the preset correction time to adapt to changes in the construction environment. Finally, within the preset determination time, the crack width is continuously monitored according to the corrected threshold, the abnormal settlement area is determined, and an abnormal prompt is issued to achieve accurate early warning.

[0040] Through the high-precision monitoring capability of the weak grating array, real-time and dynamic tracking of ground subsidence during subway construction is achieved, and the recognition accuracy of abnormal subsidence is improved. The gradual screening and dynamic adjustment of thresholds can effectively reduce misjudgment and improve the adaptability of the monitoring system. At the same time, combined with the analysis of changes in the width of bulge cracks, it can more accurately judge settlement trends and potential risks, reduce false alarms caused by stratum disturbance or construction vibration, thereby optimizing construction safety management, reducing settlement risks, and ensuring the stability of subway construction and surrounding environment, effectively solving the problem of low accuracy of monitoring results due to reliance on static and single monitoring data.

[0041] Please continue reading Figure 2 As shown, it is a determination logic diagram for determining the first temporary area in this embodiment; Determining a plurality of first temporary areas according to the real-time ground subsidence and a preset subsidence threshold comprises: When the real-time ground settlement amount is greater than the preset settlement amount threshold, the weak grating array acquisition area is determined to be the first temporary area to determine a plurality of first temporary areas.

[0042] By obtaining the real-time strain value and real-time ground settlement in the weak grating array acquisition area, first determine whether the real-time ground settlement exceeds the preset settlement threshold, and screen out the first temporary area. Subsequently, in the first temporary area, the second temporary area is further screened out in combination with the real-time strain value and the synchronization threshold, and the real-time crack width at the bulge is detected therein. The synchronization threshold is dynamically adjusted by the preset adjustment time, and the settlement threshold is corrected according to the number of the second temporary area within the preset correction time to adapt to different settlement characteristics. Finally, within the preset determination time, based on the corrected settlement threshold and crack width, the abnormal settlement area is accurately identified, and an abnormal prompt is issued to achieve full-process settlement monitoring and early warning.

[0043] Through layered screening and dynamic adjustment of thresholds, the misjudgment rate is effectively reduced, making anomaly detection more reliable. Weak grating array monitoring technology is used to ensure the accuracy of data collection, and by monitoring the width of cracks at the bulge, fine-grained analysis of stratum disturbance is achieved, which can promptly detect hidden dangers caused by construction vibration. In addition, the automated monitoring process reduces the cost of manual inspections, improves the real-time nature of early warnings, and helps to ensure the long-term stability of subway structures and surrounding buildings.

[0044] Specifically, determining a plurality of second temporary areas according to the real-time ground settlement amount, the real-time strain value and a preset synchronization threshold of each of the first temporary areas includes: Calculate the standard deviation of all the real-time ground settlement amounts within a preset synchronous calculation time to form a settlement fluctuation value; Calculating the standard deviation of all the real-time strain values ​​within the preset synchronous calculation time to form a strain fluctuation value; A plurality of second temporary areas are determined according to the settlement fluctuation value, the strain fluctuation value and the preset synchronization threshold.

[0045] The preset synchronous calculation time refers to the time window selected when calculating the settlement fluctuation value and the strain fluctuation value, which is used to ensure the time consistency of the data. It depends on the change rate of settlement and strain during subway construction and the data acquisition frequency of the monitoring system. It is usually set between 5 minutes and 30 minutes. In this embodiment, it is set to 10 minutes, which can effectively capture the short-term dynamic changes of formation disturbances and reduce the impact of instantaneous noise.

[0046] First, in the first temporary area, the standard deviation of all real-time ground settlement within the preset synchronous calculation time is calculated to obtain the settlement fluctuation value, and the standard deviation of all real-time strain values ​​within the corresponding time is calculated to obtain the strain fluctuation value. Subsequently, these two fluctuation values ​​are compared with the preset synchronization threshold to screen out areas with significant synchronous changes, and finally determine several second temporary areas. This process can effectively identify the correlation between settlement and strain values, and further lock in key areas where abnormal settlement may exist.

[0047] By calculating the standard deviation to analyze the fluctuation of settlement and strain values, the ability to finely identify formation disturbances is improved, the screening of abnormal settlement areas is more accurate, and the interference of environmental noise and local abnormal data can be effectively reduced, and the stability and reliability of monitoring data can be improved. At the same time, by setting the preset synchronization threshold, it is ensured that the second temporary area selected can truly reflect the dynamic relationship between settlement and strain, thereby improving the accuracy of subsequent crack monitoring and abnormal warning.

[0048] Please continue reading Figure 3 As shown, it is a determination logic diagram for determining the second temporary area in this embodiment; Determining a plurality of second temporary areas according to the settlement fluctuation value, the strain fluctuation value and the preset synchronization threshold comprises: Draw a change curve of the settlement fluctuation value within the preset synchronous calculation time to form a settlement fluctuation curve; Drawing a variation curve of the strain fluctuation value within the preset synchronous calculation time to form a strain fluctuation curve; Calculating the cosine similarity of the settlement fluctuation curve and the strain fluctuation curve to form synchronization; When the synchronization degree is less than the preset synchronization degree threshold, the first temporary area is determined to be the second temporary area, so as to determine a plurality of second temporary areas.

[0049] Within the preset synchronization calculation time, the settlement fluctuation value and strain fluctuation value are calculated, and the corresponding fluctuation curve is drawn. Then, the synchronization degree of the settlement fluctuation curve and the strain fluctuation curve is calculated using cosine similarity. If the synchronization degree of a first temporary area is lower than the preset synchronization degree threshold, the area is determined to be a second temporary area, thereby screening out several second temporary areas to provide a basis for subsequent analysis.

[0050] By drawing settlement and strain fluctuation curves and calculating their synchronization, unstable areas of formation deformation can be effectively identified to avoid misjudgment that may be caused by single threshold judgment. At the same time, the use of cosine similarity for analysis improves the recognition accuracy and can more accurately screen out areas with poor synchronization, thereby optimizing the determination of abnormal settlement areas and improving the sensitivity and reliability of monitoring.

[0051] Specifically, obtaining the real-time crack width of each bulge in the second temporary area according to the real-time strain values ​​in all the second temporary areas includes: Calculating the standard deviation of all the real-time strain values ​​to form a strain distribution value; When the strain distribution value is greater than a preset strain distribution threshold, the real-time crack width at each bulge in the second temporary area is obtained according to the real-time strain values ​​of any two adjacent second temporary areas.

[0052] In all second temporary areas, the standard deviation of the real-time strain value of each area is calculated to obtain the strain distribution value. When the distribution value exceeds the preset strain distribution threshold, it indicates that the area may have significant deformation. Subsequently, by analyzing the changes in the real-time strain values ​​of adjacent second temporary areas, the real-time crack width at the bulge is calculated and obtained, providing a basis for subsequent adjustments and corrections.

[0053] By calculating the strain distribution value through the standard deviation, it is possible to accurately identify areas where strain anomalies are concentrated, and determine the crack width in combination with the strain value change trend in adjacent areas, thereby improving the accuracy of crack identification. It can not only effectively detect the bulging deformation of the formation, but also provide more fine-grained crack information for settlement monitoring, making the monitoring results more accurate and improving the safety and early warning capabilities during subway construction.

[0054] Specifically, obtaining the real-time crack width of each bulge in the second temporary area according to the real-time strain values ​​of any two adjacent second temporary areas includes: Obtaining the distance between the two second temporary areas; Calculating a difference between the real-time strain values ​​of the two second temporary areas to form a strain difference; Calculating a ratio of the strain difference to the distance to form a strain gradient; When the strain gradient is greater than a preset gradient threshold, determining the midpoint of the two second temporary areas as the midpoint of the bulge to form the bulge midpoint; Get the width of all cracks in a circular area with the midpoint of the bulge as the circle point and the preset bulge length as the radius; The average of all said widths is calculated to form the real-time crack width.

[0055] Wherein, obtaining the distance between the two second temporary areas includes: This is done by calculating the Euclidean distance between the center points of the two areas. First, the center coordinates of the two second temporary areas are determined based on the grid distribution of the weak grating array sensor. Then, the straight-line distance between the two points is calculated using the Euclidean distance formula, which can accurately obtain the spatial separation distance between the two temporary areas, thereby providing basic data for further crack width calculations.

[0056] The width of all cracks in a circular area with the midpoint of the bulge as the center and the preset bulge length as the radius is obtained by an ultrasonic sensor. The ultrasonic sensor can accurately detect the existence and size of cracks by emitting high-frequency sound waves and measuring the reflection time of the sound waves. By analyzing the time difference and intensity change of the ultrasonic return signal, the precise width of the crack can be calculated, thereby providing reliable crack monitoring data.

[0057] The preset bulge length refers to the standard length of the radius of the bulge area used to calculate the crack width, which depends on the geological conditions, construction impact and monitoring accuracy requirements, and is usually set between 10 meters and 30 meters. In this embodiment, it is set to 20 meters, which can effectively cover the bulge impact area generated during the construction process and provide sufficient data for accurately calculating the crack width, ensuring the reliability and accuracy of the monitoring results.

[0058] First, the distance between two adjacent second temporary areas is obtained, and the difference in their real-time strain values ​​is calculated to obtain the strain difference. The strain gradient is calculated by the ratio of the strain difference to the area distance to determine the degree of local deformation. When the strain gradient exceeds the preset gradient threshold, the midpoint of the two areas is determined to be the midpoint of the bulge. Then, with the midpoint of the bulge as the center of the circle and the preset bulge length as the radius, the detection range is defined, the width of all cracks within the range is obtained, and the average value is calculated to finally form the real-time crack width.

[0059] The formation position of the bulge can be accurately located through strain gradient calculation to ensure the accuracy of bulge detection. At the same time, the crack width is analyzed with the bulge as the center, making the crack monitoring range more targeted and improving the reliability of crack width calculation. Combined with the deformation characteristics of the local area, hidden dangers that may affect the safety of subway construction can be identified in time, providing more accurate data support for subsequent adjustments and corrections.

[0060] Specifically, adjusting the preset synchronization threshold according to the real-time crack width within the preset adjustment time to form the adjustment synchronization threshold includes: Calculating the standard deviation of the real-time crack width to form a first width fluctuation value; When the first width fluctuation value is greater than the preset first width fluctuation threshold, the preset synchronization threshold is reduced according to the relative deviation between the crack width fluctuation value and the preset width fluctuation threshold and the preset adjustment coefficient to form an adjusted synchronization threshold, wherein the relative deviation between the crack width fluctuation value and the preset width fluctuation threshold is positively correlated with the adjusted synchronization threshold.

[0061] The preset first width fluctuation threshold is a standard value used to determine whether the crack width fluctuation is significant. It depends on the environmental characteristics and monitoring requirements of the construction area. It is usually set between 0.1 mm and 2 mm. In this embodiment, it is set to 1 mm. It can ensure that abnormal changes are detected in time under normal construction vibration and ground subsidence, while avoiding false alarms caused by overly sensitive fluctuations.

[0062] The preset adjustment coefficient is used to adjust the synchronization threshold when the crack width fluctuation exceeds the threshold. It depends on the response speed and accuracy requirements of the actual monitoring system. It is usually set between 0.1 and 0.5. In this embodiment, it is set to 0.2, which can reasonably reduce the synchronization threshold so that the system can more sensitively capture potential settlement problems when the crack width changes.

[0063] Within the preset adjustment time, the standard deviation of the real-time crack width is calculated to obtain a first width fluctuation value. When the crack width fluctuation value is greater than the preset first width fluctuation threshold, the synchronization threshold is reduced according to the relative deviation between the crack width fluctuation value and the preset threshold and the preset adjustment coefficient, thereby forming an adjusted synchronization threshold.

[0064] By dynamically adjusting the preset synchronization threshold, we can flexibly respond to large fluctuations in crack width during construction, improve the sensitivity and accuracy of monitoring, ensure that we can capture small changes in ground subsidence and deformation in a timely manner, and enhance the real-time response capability and monitoring accuracy of monitoring.

[0065] Specifically, the preset settlement amount threshold is corrected according to the number of the second temporary areas determined based on the adjustment synchronization threshold within the preset correction time period to form the corrected settlement amount threshold, which includes: Calculating the standard deviation of the quantity in the second temporary area to form a quantity fluctuation value; When the quantity fluctuation value is greater than a preset quantity fluctuation threshold, a relative deviation between the quantity fluctuation value and the preset quantity fluctuation threshold is calculated to form a quantity fluctuation deviation; When the quantity fluctuation deviation is greater than the preset fluctuation deviation threshold, the preset settlement amount threshold is reduced according to the relative deviation between the quantity fluctuation deviation and the preset fluctuation deviation threshold and the preset correction coefficient to form a corrected settlement amount threshold, wherein the relative deviation between the quantity fluctuation deviation and the preset fluctuation deviation threshold is positively correlated with the corrected settlement amount threshold.

[0066] The preset quantity fluctuation threshold refers to the maximum value allowed for the quantity fluctuation in the second temporary area within the preset correction time. It depends on the actual construction conditions and the settlement monitoring accuracy requirements. It is usually set between 1 and 10. In this embodiment, it is set to 5, which can balance the response to abnormal fluctuations and avoid the need for excessive adjustments, and promptly reflect obvious settlement changes during the construction process.

[0067] The preset fluctuation deviation threshold refers to the condition for correcting the settlement threshold when the quantity fluctuation deviation exceeds this threshold. It depends on the changes in the construction environment and the requirements of the monitoring strategy. It is usually set between 0.1 and 0.5. In this embodiment, it is set to 0.3, which helps to make reasonable adjustments in the event of large fluctuations, while avoiding frequent adjustments caused by minor fluctuations.

[0068] The preset correction coefficient refers to the coefficient adjusted based on the quantity fluctuation deviation when correcting the sedimentation threshold. It depends on the accuracy of the monitoring equipment and the sensitivity of the sedimentation threshold. It is usually set between 0.5 and 2. In this embodiment, it is set to 1.5, which can reasonably adjust the sedimentation threshold and avoid inaccurate monitoring caused by excessive correction.

[0069] First, the standard deviation of the quantity in the second temporary area is calculated to form a quantity fluctuation value. When the quantity fluctuation value exceeds a preset quantity fluctuation threshold, the relative deviation between the quantity fluctuation value and the preset threshold is calculated to form a quantity fluctuation deviation. When the quantity fluctuation deviation exceeds the preset fluctuation deviation threshold, the preset settlement threshold is adjusted according to the relative deviation between the quantity fluctuation deviation and the preset fluctuation deviation threshold and the preset correction coefficient to form a corrected settlement threshold.

[0070] The settlement threshold is adjusted dynamically according to the fluctuation of the number of second temporary areas actually monitored, thereby improving the accuracy of settlement monitoring. When the abnormal settlement fluctuation in the area increases, the threshold can be adjusted in time to prevent false alarms caused by overly strict thresholds, while ensuring accurate response to real abnormal settlement events, effectively improving the sensitivity and reliability of monitoring.

[0071] Specifically, determining a number of abnormal settlement areas according to the real-time crack width obtained based on the modified settlement threshold within a preset determination time period includes: Calculating the standard deviation of the real-time crack width to form a second width fluctuation value; When the second width fluctuation value is greater than a preset second width fluctuation threshold, the second temporary area where the corresponding circular area is located is determined to be the abnormal settlement area, so as to determine a plurality of abnormal settlement areas.

[0072] The preset second width fluctuation threshold is a standard value used to determine whether the crack width fluctuation is abnormal. It depends on the geological characteristics of the construction area, equipment accuracy and monitoring requirements. It is usually set between 0.1 mm and 2 mm. In this embodiment, it is set to 1 mm. While ensuring the monitoring sensitivity, it can avoid too frequent false alarms and improve the practicality and accuracy of the monitoring system.

[0073] By calculating the standard deviation of the real-time crack width, the second width fluctuation value is obtained, and then it is determined whether the fluctuation value exceeds the preset second width fluctuation threshold. If it exceeds the threshold, the area is determined to be an abnormal settlement area. In this way, the area where the ground has abnormal settlement can be identified and located, thereby ensuring real-time monitoring and timely adjustment of the construction area.

[0074] By analyzing the fluctuation of crack width, it is possible to accurately identify abnormal settlement areas caused by settlement, so as to quickly respond to potential construction risks. By setting a reasonable fluctuation threshold, it is possible to avoid overly sensitive detection, ensure the stability and efficiency of the monitoring system, and issue early warnings in a timely manner, providing an effective basis for subsequent construction adjustments.

[0075] On the other hand, please continue to see Figure 4 As shown, it is a schematic diagram of the ground subsidence monitoring system based on weak grating array monitoring in this embodiment; This embodiment also provides a ground subsidence monitoring system based on weak grating array monitoring, including: The first acquisition module is used to obtain the real-time strain value and real-time ground settlement of each weak grating array acquisition area during the subway shield construction process; A first determination module, connected to the first acquisition module, for determining a plurality of first temporary areas according to the real-time ground subsidence and a preset subsidence threshold; A second determination module, which is connected to the first acquisition module and the first determination module respectively, and is used to determine a plurality of second temporary areas according to the real-time ground settlement amount, the real-time strain value and a preset synchronization threshold of each of the first temporary areas; A second acquisition module, connected to the second determination module, for acquiring a real-time crack width at each bulge in the second temporary area according to the real-time strain values ​​in all the second temporary areas; an adjustment module, which is connected to the second determination module and the second acquisition module respectively, and is used to adjust the preset synchronization threshold according to the real-time crack width within a preset adjustment time period to form an adjusted synchronization threshold; a correction module, which is connected to the first determination module, the adjustment module and the second determination module respectively, and is used to correct the preset settlement amount threshold according to the number of the second temporary areas determined based on the adjustment synchronization threshold within a preset correction time period to form a corrected settlement amount threshold; a third determination module, which is connected to the correction module and the second acquisition module respectively, and is used to determine a number of abnormal settlement areas according to the real-time crack width obtained based on the correction settlement threshold within a preset determination time period; A prompt module is connected to the third determination module and is used to issue an abnormal prompt according to the abnormal settlement area.

[0076] Through the cooperation of multiple modules, the real-time strain value and ground settlement of the weak grating array during the subway shield construction process are first obtained. Based on the preset settlement threshold, the system determines several first temporary areas, and then further refines them into second temporary areas according to the synchronization threshold. On this basis, the system calculates the crack width and adjusts the synchronization threshold according to the real-time crack width. By correcting the settlement threshold, the system can accurately determine the abnormal settlement area within the preset time, and finally issue an abnormal prompt to timely warn of possible ground settlement problems during the construction process.

[0077] Through accurate real-time monitoring of ground subsidence, the monitoring parameters can be dynamically adjusted according to the actual data during the construction process, providing more refined anomaly detection. By adjusting the preset synchronization threshold and the preset settlement threshold, the system improves the accuracy and flexibility of monitoring, avoiding construction safety hazards caused by untimely detection of settlement problems. In addition, early identification of abnormal settlement areas can help relevant personnel take quick measures to effectively reduce construction risks and improve construction safety.

[0078] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A method for monitoring ground subsidence based on weak grating array monitoring, characterized in that: include: Obtain the real-time strain value and real-time ground settlement of each weak grating array acquisition area during subway shield construction; Determine a plurality of first temporary areas according to the real-time ground subsidence and a preset subsidence threshold; Determine a plurality of second temporary areas according to the real-time ground settlement amount, the real-time strain value and a preset synchronization threshold of each of the first temporary areas; Obtaining a real-time crack width at each bulge in the second temporary area according to the real-time strain values ​​in all the second temporary areas; Adjust the preset synchronization threshold according to the real-time crack width within the preset adjustment time to form an adjusted synchronization threshold; Correcting the preset settlement threshold according to the number of the second temporary areas determined based on the adjustment synchronization threshold within a preset correction time period to form a corrected settlement threshold; Determine a number of abnormal settlement areas according to the real-time crack width obtained based on the modified settlement threshold within a preset determination time period; An abnormal prompt is issued according to the abnormal settlement area.

2. The method for monitoring ground subsidence based on weak grating array monitoring according to claim 1, characterized in that: Determining a plurality of first temporary areas according to the real-time ground subsidence and a preset subsidence threshold comprises: When the real-time ground settlement amount is greater than the preset settlement amount threshold, the weak grating array acquisition area is determined to be the first temporary area to determine a plurality of first temporary areas.

3. The method for monitoring ground subsidence based on weak grating array monitoring according to claim 2, characterized in that: Determining a plurality of second temporary areas according to the real-time ground settlement amount, the real-time strain value and a preset synchronization threshold of each of the first temporary areas includes: Calculate the standard deviation of all the real-time ground settlement amounts within a preset synchronous calculation time to form a settlement fluctuation value; Calculating the standard deviation of all the real-time strain values ​​within the preset synchronous calculation time to form a strain fluctuation value; A plurality of second temporary areas are determined according to the settlement fluctuation value, the strain fluctuation value and the preset synchronization threshold.

4. The method for monitoring ground subsidence based on weak grating array monitoring according to claim 3 is characterized in that: Determining a plurality of second temporary areas according to the settlement fluctuation value, the strain fluctuation value and the preset synchronization threshold comprises: Draw a change curve of the settlement fluctuation value within the preset synchronous calculation time to form a settlement fluctuation curve; Drawing a variation curve of the strain fluctuation value within the preset synchronous calculation time to form a strain fluctuation curve; Calculating the cosine similarity of the settlement fluctuation curve and the strain fluctuation curve to form synchronization; When the synchronization degree is less than the preset synchronization degree threshold, the first temporary area is determined to be the second temporary area, so as to determine a plurality of second temporary areas.

5. The method for monitoring ground subsidence based on weak grating array monitoring according to claim 4, characterized in that: Acquiring the real-time crack width of each bulge in the second temporary area according to the real-time strain values ​​in all the second temporary areas comprises: Calculating the standard deviation of all the real-time strain values ​​to form a strain distribution value; When the strain distribution value is greater than a preset strain distribution threshold, the real-time crack width at each bulge in the second temporary area is obtained according to the real-time strain values ​​of any two adjacent second temporary areas.

6. The method for monitoring ground subsidence based on weak grating array monitoring according to claim 5, characterized in that: Acquiring the real-time crack width of each bulge in the second temporary area according to the real-time strain values ​​of any two adjacent second temporary areas comprises: Obtaining the distance between the two second temporary areas; Calculating a difference between the real-time strain values ​​of the two second temporary areas to form a strain difference; Calculating a ratio of the strain difference to the distance to form a strain gradient; When the strain gradient is greater than a preset gradient threshold, determining the midpoint of the two second temporary areas as the midpoint of the bulge to form the midpoint of the bulge; Get the width of all cracks in a circular area with the midpoint of the bulge as the circle point and the preset bulge length as the radius; The average of all said widths is calculated to form the real-time crack width.

7. The method for monitoring ground subsidence based on weak grating array monitoring according to claim 6, characterized in that: Adjusting the preset synchronization threshold according to the real-time crack width within the preset adjustment time to form the adjustment synchronization threshold includes: Calculating the standard deviation of the real-time crack width to form a first width fluctuation value; When the first width fluctuation value is greater than a preset first width fluctuation threshold, the preset synchronization threshold is reduced according to the relative deviation between the crack width fluctuation value and the preset width fluctuation threshold and a preset adjustment coefficient to form an adjusted synchronization threshold.

8. The method for monitoring ground subsidence based on weak grating array monitoring according to claim 7, characterized in that: Correcting the preset settlement threshold according to the number of the second temporary areas determined based on the adjustment synchronization threshold within a preset correction time period to form a corrected settlement threshold includes: Calculating the standard deviation of the quantity in the second temporary area to form a quantity fluctuation value; When the quantity fluctuation value is greater than a preset quantity fluctuation threshold, a relative deviation between the quantity fluctuation value and the preset quantity fluctuation threshold is calculated to form a quantity fluctuation deviation; When the quantity fluctuation deviation is greater than the preset fluctuation deviation threshold, the preset settlement amount threshold is reduced according to the relative deviation between the quantity fluctuation deviation and the preset fluctuation deviation threshold and a preset correction coefficient to form a corrected settlement amount threshold.

9. The method for monitoring ground subsidence based on weak grating array monitoring according to claim 8, characterized in that: Determining a number of abnormal settlement areas according to the real-time crack width obtained based on the modified settlement threshold within a preset determination time period includes: Calculating the standard deviation of the real-time crack width to form a second width fluctuation value; When the second width fluctuation value is greater than a preset second width fluctuation threshold, the corresponding circular area is determined to be the abnormal settlement area, so as to determine a plurality of abnormal settlement areas.

10. A ground subsidence monitoring system based on weak grating array monitoring, based on the ground subsidence monitoring method based on weak grating array monitoring according to any one of claims 1 to 9, characterized in that: include: The first acquisition module is used to obtain the real-time strain value and real-time ground settlement of each weak grating array acquisition area during the subway shield construction process; a first determining module, connected to the first acquiring module, for determining a plurality of first temporary areas according to the real-time ground subsidence and a preset subsidence threshold; A second determination module, which is connected to the first acquisition module and the first determination module respectively, and is used to determine a plurality of second temporary areas according to the real-time ground settlement amount, the real-time strain value and a preset synchronization threshold of each of the first temporary areas; A second acquisition module, connected to the second determination module, for acquiring a real-time crack width at each bulge in the second temporary area according to the real-time strain values ​​in all the second temporary areas; an adjustment module, which is connected to the second determination module and the second acquisition module respectively, and is used to adjust the preset synchronization threshold according to the real-time crack width within a preset adjustment time period to form an adjusted synchronization threshold; a correction module, which is connected to the first determination module, the adjustment module and the second determination module respectively, and is used to correct the preset settlement amount threshold according to the number of the second temporary areas determined based on the adjustment synchronization threshold within a preset correction time period to form a corrected settlement amount threshold; a third determination module, which is connected to the correction module and the second acquisition module respectively, and is used to determine a number of abnormal settlement areas according to the real-time crack width obtained based on the correction settlement threshold within a preset determination time period; A prompt module is connected to the third determination module and is used to issue an abnormal prompt according to the abnormal settlement area.

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