A tunnel structure monitoring system based on multi-source perception

Abstract

This invention discloses a tunnel structure monitoring system based on multi-source sensing, belonging to the field of structural monitoring technology. It addresses the problem of reduced reliability in tunnel structure defect identification and risk warning. The system divides the tunnel lining area into zones based on historical grouting maintenance information. Under vehicle traffic excitation, structural vibration data for each zone is collected, and the transmission discontinuity trend is analyzed. Combined with grouting peak pressure from a historical database, a grouting reference level characterizing the intensity of historical grouting influence is generated. Based on this, seepage conductivity and lining surface temperature are collected, and grouting sealing characteristics are evaluated. The grouting sealing characteristics are corrected under the constraint of historical grouting background to determine whether there is a risk of cavity activation. By first establishing an inherent abnormal background caused by maintenance and then identifying new risks within this background, the system reduces the occurrence of misjudging historical maintenance characteristics as cavity defects, thus improving the reliability of defect warnings.

Description

Technical Field

[0001] This invention relates to the field of structural monitoring technology, and more specifically, to a tunnel structural monitoring system based on multi-source sensing. Background Technology

[0002] During long-term service, tunnel projects are susceptible to structural hazards such as voids and cavities behind the lining due to factors such as groundwater seepage, stress redistribution in the surrounding rock, and repeated vehicle loads. To eliminate these hazards, grouting is usually used in the operation and maintenance of the project to reinforce and seal the back of the lining, so as to restore the mechanical transmission and seepage prevention performance between the lining and the surrounding rock.

[0003] The existing technology has the following shortcomings: Currently, existing technologies mostly rely on single-sensor information or static threshold rules to determine the state of tunnel lining. Especially after the lining has undergone grouting maintenance, the historical grouting process and its inherent impact on the structural response are not modeled and constrained. It is difficult to effectively distinguish between the structural anomalies introduced by historical grouting maintenance and the cavity risk characteristics newly added during service. As a result, in the monitoring results of vibration response, seepage changes or apparent wet spots, historical maintenance characteristics are easily misjudged as cavity defects, reducing the reliability of tunnel structural defect identification and risk warning. Therefore, a tunnel structural monitoring system based on multi-source sensing is proposed.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a tunnel structure monitoring system based on multi-source sensing. This system addresses the problems mentioned in the background art by employing a zonal modeling method constrained by historical grouting maintenance information, a structural vibration discontinuity identification mechanism under vehicle traffic excitation, and a seepage-temperature sealing feature correction strategy that integrates grouting reference layers.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a tunnel structure monitoring system based on multi-source sensing, comprising a disconnection identification module, a benchmark construction module, a closure assessment module, and a cavity discrimination module, the functions of each module being as follows: The disconnection identification module acquires the grouting maintenance information of the lining area to be tested, and divides the lining area to be tested into zones based on the grouting maintenance information. When a vehicle enters a zone, the module collects the structural vibration data of the zone and generates a transmission disconnection trend, which is then transmitted to the baseline construction module. The baseline construction module is used to access the historical database to retrieve the peak grouting pressure of the designated area, use the peak grouting pressure to perform abrupt change screening analysis to generate the grouting solidification index, and combine the grouting solidification index with the transmission discontinuity trend to locate the grouting reference level of the designated area, and then pass the grouting reference level into the cavity discrimination module. The sealing assessment module is used to collect the seepage conductivity and lining surface temperature of each designated zone, calculate the temperature hysteresis coefficient based on the lining surface temperature, assess the grouting sealing characteristics in combination with the seepage conductivity, use the grouting sealing characteristics to screen and mark the designated zones, and then transmit the marked designated zones to the cavity discrimination module. The cavity discrimination module is used to detect the number of wet spots in the marked and delineated areas, correct the grouting and sealing characteristics according to the grouting reference level, and determine whether to trigger a cavity regeneration prompt based on the number of wet spots.

[0007] In a preferred embodiment, the disconnection identification module obtains grouting maintenance information of the lining area to be tested from a historical database, including the type of grouting material and the range of grouting locations. Among them, the grouting material type refers to the type of grout in the maintenance batch; the grouting location range refers to the spatial range of the grouting operation in the tunnel lining; Based on the grouting location range, the grouting action range corresponding to the maintenance batch is extracted. Using the grouting action range as the basic boundary, the lining area to be tested is divided into multiple initial sections. Furthermore, the consistency of grouting material type is judged for initial sections that are adjacent or have overlapping areas, resulting in different delineation zones.

[0008] In a preferred embodiment, in the disconnection identification module, when a vehicle enters a designated zone, the moment when the vehicle enters the boundary of the designated zone is taken as the entry moment, and within a preset entry acquisition time after the entry moment, vibration response signals are acquired by an acceleration sensor, and the vibration acceleration amplitude sequence in the vibration response signals is extracted as structural vibration data on the entry side. The departure time is defined as the moment when the vehicle approaches the exit boundary of the designated zone and leaves the designated zone. Within the preset departure acquisition time before the departure time, vibration response signals are acquired and vibration acceleration amplitude sequences are extracted as structural vibration data on the exit side.

[0009] In a preferred embodiment, in the disconnection identification module, the average values ​​of the structural vibration data on the entry side and the exit side are calculated respectively to obtain the average amplitude of vibration on the entry side and the average amplitude of vibration on the exit side. The vibration transmission ratio is obtained by calculating the ratio of the average amplitude of the vibration on the inlet side to the average amplitude of the vibration on the outlet side. Within a preset statistical period, the vibration transmission ratios of each defined zone are recorded in chronological order, and the vibration transmission ratios of two adjacent zones are compared to screen for events that exacerbate the disconnection. The transmission disconnection trend is calculated based on the number of disconnection events within a preset statistical period.

[0010] In a preferred embodiment, the baseline construction module accesses the historical database to retrieve the peak grouting pressure of the defined zone; The peak grouting pressure was used for abrupt change screening analysis. Specifically, the peak grouting pressures within the same defined zone were arranged in chronological order to form a grouting peak pressure sequence. The difference between adjacent grouting peak pressures is calculated to obtain the peak pressure change amplitude. The peak pressure change amplitude is compared with the preset peak pressure change threshold to screen out grouting pressure abrupt events. The grouting pressure abrupt events in the grouting peak pressure sequence are statistically analyzed to obtain the number of grouting pressure abrupt events, and the grouting solidification index is calculated based on the number of grouting pressure abrupt events. The grouting curing index and the transmission discontinuity trend were standardized to obtain the grouting curing coefficient and the transmission discontinuity coefficient, respectively. The grouting reference layer is calculated based on the grouting curing coefficient and the transmission discontinuity coefficient.

[0011] In a preferred embodiment, in the sealing assessment module, the seepage conductivity and lining surface temperature of each designated zone are collected synchronously within a preset monitoring period to form a time series. The seepage conductivity is obtained by the conductivity sensing unit, and its physical meaning is the ability of water to pass through the lining-surrounding rock system under a unit potential gradient. The surface temperature of the lining is continuously collected by the temperature sensing unit, reflecting the thermal response state of the lining structure under the combined effects of ambient temperature disturbance and internal medium heat conduction. After obtaining the time series of the lining surface temperature, the first time derivative of the lining surface temperature is calculated to obtain the rate of temperature change. Within the same time interval corresponding to the time series, the rate of change of the environmental reference temperature is obtained, and the temperature hysteresis coefficient is defined as: ; in, The temperature hysteresis coefficient, For the rate of temperature change, For the rate of change of ambient reference temperature, It is a preset small positive number.

[0012] In a preferred embodiment, in the plugging evaluation module, the seepage conductivity and temperature hysteresis coefficient are normalized to obtain normalized seepage conductivity and normalized temperature hysteresis coefficient, and grouting plugging characteristics are constructed: ; in, This is a characteristic of grouting and sealing. This is the normalized temperature hysteresis coefficient. To normalize the percolation conductivity, It is a preset positive constant; When the grouting and sealing characteristics are lower than the preset sealing judgment threshold, the determination is to screen and mark the delineated areas to form marked delineated areas; When the grouting and sealing characteristics are not lower than the preset sealing judgment threshold, the zone is determined to be a stable sealing state zone and no marking process is performed.

[0013] In a preferred embodiment, the cavity discrimination module acquires the lining surface image corresponding to the marked and delineated partition, and detects and counts the number of wet spots appearing on the lining surface. By introducing the grouting reference level output by the baseline construction module, a linear reduction correction is performed on the grouting sealing features, and the corrected grouting sealing features are defined as follows: ; in, To correct the grouting and sealing characteristics, This is a characteristic of grouting and sealing. This serves as a reference layer for grouting. The number of wet spots is normalized by area, and the wet spot density is defined as the ratio of the number of wet spots to the lining surface area of ​​the corresponding marked partition. The wet spot density is normalized to obtain the normalized wet spot density.

[0014] In a preferred embodiment, in the cavity discrimination module, after obtaining the modified grouting and sealing characteristics and the normalized wet spot density, a cavity activation discrimination index is constructed: ; in, The cavity activation discriminant index, To normalize the wet spot density, To correct the grouting and sealing characteristics, and The preset exponential coefficient; When the cavity activation discrimination index is greater than or equal to the cavity activation judgment threshold, it is determined that there is a risk of cavity reactivation in the corresponding marked area, triggering a cavity regeneration prompt. When the cavity activation discrimination index is less than the cavity activation judgment threshold, it is determined that there is no risk of cavity reactivation in the corresponding marked area, and cavity regeneration prompt is not triggered. The cavity regeneration prompt is a risk indication information output by the cavity discrimination module, used to characterize the possibility that a cavity in the corresponding defined partition may be re-established and enter an active state.

[0015] The technical effects and advantages of this invention are as follows: This invention divides the tunnel lining area into zones based on historical grouting maintenance information. Under vehicle traffic excitation, it collects structural vibration data for each zone, analyzes the transmission discontinuity trend, and combines the peak grouting pressure in the historical database to generate a grouting reference level characterizing the intensity of historical grouting influence. Based on this, it collects seepage conductivity and lining surface temperature and evaluates grouting sealing characteristics. Under the constraint of historical grouting background, it corrects the grouting sealing characteristics to determine whether there is a risk of cavity activation. By first establishing the inherent abnormal background caused by maintenance and then identifying new risks under this background, it reduces the occurrence of misjudging historical maintenance characteristics as cavity defects and improves the reliability of defect indication. Attached Figure Description

[0016] Figure 1 This is a process flowchart of a tunnel structure monitoring system based on multi-source sensing according to the present invention.

[0017] Figure 2 This is a module implementation diagram of a tunnel structure monitoring system based on multi-source sensing according to the present invention. Detailed Implementation

[0018] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This invention divides the tunnel lining area into zones based on historical grouting maintenance information. Under vehicle traffic excitation, it collects structural vibration data for each zone, analyzes the transmission discontinuity trend, and combines the peak grouting pressure in the historical database to generate a grouting reference level characterizing the intensity of historical grouting influence. Based on this, it collects seepage conductivity and lining surface temperature and evaluates grouting sealing characteristics. Under the constraint of historical grouting background, it corrects the grouting sealing characteristics to determine whether there is a risk of cavity activation. By first establishing the inherent abnormal background caused by maintenance and then identifying new risks under this background, it reduces the occurrence of misjudging historical maintenance characteristics as cavity defects.

[0020] Example 1, such as Figures 1 to 2As shown, a tunnel structure monitoring system based on multi-source sensing includes a disconnection identification module, a benchmark construction module, a blockage assessment module, and a cavity discrimination module. The modules interact with each other through signal connections. The functions of each module are as follows: The disconnection identification module acquires the grouting maintenance information of the lining area to be tested, and divides the lining area to be tested into zones based on the grouting maintenance information. When a vehicle enters a zone, the module collects the structural vibration data of the zone and generates a transmission disconnection trend, which is then transmitted to the baseline construction module. The baseline construction module is used to access the historical database to retrieve the peak grouting pressure of the designated area, use the peak grouting pressure to perform abrupt change screening analysis to generate the grouting solidification index, and combine the grouting solidification index with the transmission discontinuity trend to locate the grouting reference level of the designated area, and then pass the grouting reference level into the cavity discrimination module. The sealing assessment module is used to collect the seepage conductivity and lining surface temperature of each designated zone, calculate the temperature hysteresis coefficient based on the lining surface temperature, assess the grouting sealing characteristics in combination with the seepage conductivity, use the grouting sealing characteristics to screen and mark the designated zones, and then transmit the marked designated zones to the cavity discrimination module. The cavity discrimination module is used to detect the number of wet spots in the marked and delineated areas, correct the grouting and sealing characteristics according to the grouting reference level, and determine whether to trigger a cavity regeneration prompt based on the number of wet spots.

[0021] The specific implementation is as follows: In the discontinuity identification module, if the inherent structural discontinuity background formed by the lining area under test after multiple grouting repairs is not distinguished during the monitoring and judgment process, the structural features left over from the repairs may be misjudged as new risks. Based on the grouting repair information and the structural response under vehicle traffic excitation, an abnormal background reflecting the impact of grouting repairs is constructed. Under the constraint of this background, the structural state is corrected and judged in combination with seepage, temperature and appearance characteristics, so as to identify whether there is cavity reactivation.

[0022] The grouting maintenance information of the lining area to be tested is obtained from the historical database. The grouting maintenance information refers to the historical maintenance record information formed by multiple grouting maintenances of the lining area to be tested, including the type of grouting material and the range of grouting locations. Among them, the grouting material type refers to the type of grout in the maintenance batch; the grouting location range refers to the spatial range of the grouting operation in the tunnel lining; When dividing the lining area to be tested into zones, the grouting action range corresponding to the maintenance batch is extracted according to the grouting location range. The grouting action range is used as the basic boundary to divide the lining area to be tested into multiple initial sections. Furthermore, the consistency of grouting material type is judged for initial segments that are adjacent or have overlapping areas. When the grouting material types of adjacent segments are consistent, they are merged into the same delineated zone; when the grouting material types are inconsistent, the location of the material type change is used as the zone boundary to form different delineated zones. When a vehicle enters a designated zone, the moment when the vehicle enters the boundary of the designated zone is taken as the entry moment, and structural vibration data of the designated zone is collected within a preset entry collection time after the entry moment. Among them, vibration response signals are collected by accelerometers, and the vibration acceleration amplitude sequence in the vibration response signals is extracted as structural vibration data on the entry side; The departure time is defined as the moment when the vehicle approaches the exit boundary of the designated zone and leaves the designated zone. Within the preset departure acquisition time before the departure time, vibration response signals are acquired from the designated zone and vibration acceleration amplitude sequences are extracted as structural vibration data on the exit side.

[0023] The average values ​​of the structural vibration data on the entry side and the exit side are calculated separately to obtain the average vibration amplitude on the entry side and the average vibration amplitude on the exit side. The vibration transmission ratio is calculated by comparing the average amplitude of the vibration on the entry side with the average amplitude of the vibration on the exit side. This ratio reflects the amplitude change of the structural vibration in the section before and after vehicle passage. The larger the value, the more obvious the attenuation of the vibration amplitude within the designated zone. A preset statistical period is set. Within the preset statistical period, the vibration transmission ratios of each defined zone are recorded in chronological order. The vibration transmission ratios of two adjacent vibration transmission ratios are compared. If the vibration transmission ratio of the later vibration transmission ratio is greater than that of the earlier vibration transmission ratio, a disconnection event is recorded; otherwise, no record is made. The ratio of the number of disconnection events within the preset statistical period to the total number of comparisons is calculated to obtain the transmission disconnection trend of the designated zone. This reflects whether the transmission attenuation phenomenon of structural vibration in the designated zone shows a continuously increasing evolutionary characteristic. The larger the value, the more frequently the vibration transmission weakening phenomenon caused by structural discontinuity occurs in the designated zone. The disconnection trend is passed to the baseline construction module.

[0024] It should be explained that the historical operation and maintenance database is a data storage system used to store maintenance information of the tunnel structure during its service life; the preset entry and exit collection durations can be set according to the average driving speed of passing vehicles and the spatial length of the designated zones; the accelerometer is a vibration acquisition device used to collect the acceleration change signal generated by the structure under external loads; the preset statistical period can be set according to the traffic flow characteristics and monitoring frequency requirements of the tunnel structure.

[0025] In the benchmark construction module, the historical database is accessed to retrieve the peak grouting pressure of the designated zone. The peak grouting pressure refers to the maximum grouting pressure value extracted when grout is injected into the designated zone during the grouting operation of the corresponding maintenance batch. The larger the value, the more fully the structural voids are filled by grout during the grouting process. The peak grouting pressure was used for abrupt change screening analysis. Specifically, the peak grouting pressures within the same defined zone were arranged in chronological order to form a grouting peak pressure sequence. The difference between adjacent grouting peak pressures is calculated to obtain the peak pressure change range. The peak pressure change range is then compared with a preset peak pressure change threshold to determine whether there is a sudden grouting pressure event. If the peak pressure change is greater than the preset peak pressure change threshold, it is marked as a grouting pressure change event; otherwise, it is not considered a grouting pressure change event. The number of grouting pressure abrupt events in the grouting peak pressure sequence is statistically analyzed to obtain the number of grouting pressure abrupt events. The ratio of the number of grouting pressure abrupt events to the total number of statistical grouting peak pressure differences is calculated to obtain the grouting solidification index for the delineated zone. The grouting curing index reflects the stability of the pressure response during the grouting operation within the designated zone. The higher the value, the higher the frequency of sudden changes in the peak grouting pressure between different maintenance batches, indicating that there are significant changes in the pore state or permeability conditions of the structure during the grouting process, and the consistency of the grouting curing state is low.

[0026] The grouting curing index and the transmission discontinuity trend were standardized to obtain the grouting curing coefficient and the transmission discontinuity coefficient, respectively. Calculation of grouting reference layer based on grouting curing coefficient and transmission discontinuity coefficient: ,in, and As a preset adjustment factor, The curing coefficient of the grouting is... To transmit the disconnection coefficient, This serves as a reference layer for grouting. The larger the grouting reference level, the stronger the structural discontinuity background formed by historical grouting maintenance in the delineated area, and there is a risk of misjudging the structural response abnormalities caused by historical grouting maintenance background as newly added cavities during service. The grouting reference level is passed to the cavity discrimination module.

[0027] It should be explained that the preset peak pressure change threshold can be set according to the quantile value or fluctuation range of the historical grouting peak pressure change amplitude; the standardization processing method includes, but is not limited to, standard linear transformation based on interval scaling, Z-Score standardization method based on statistics, or normalization method based on nonlinear mapping function. The application method of standardization processing will not be elaborated here; the preset adjustment factor can be set according to the sensitivity of the tunnel structure to historical maintenance background or vehicle load characteristics.

[0028] In the sealing assessment module, time-series data of seepage conductivity and lining surface temperature are simultaneously collected for each designated zone within a preset monitoring period, forming a time series. Seepage conductivity is obtained by conductivity sensing units deployed behind the lining. Its physical meaning is the conductivity of water through the lining-surrounding rock system under a unit potential gradient. Seepage conductivity reflects the connectivity of water channels behind the lining; a higher value indicates lower water flow resistance and weaker sealing ability of the grouting material; a lower value indicates higher obstruction of the seepage channels and a more significant sealing effect.

[0029] The surface temperature of the lining is continuously collected by temperature sensing units deployed on the lining surface. This data reflects the thermal response of the lining structure under the combined effects of ambient temperature disturbances and internal medium heat conduction. The magnitude of the change reflects the continuity of the heat transfer path of the medium behind the lining and the grouting filling state. The larger the magnitude of the change, the more easily the surface temperature of the lining changes with the ambient temperature, the more continuous the heat transfer path of the medium behind the lining, and the possible presence of voids or water channels inside. The smaller the magnitude of the change, the more effectively the temperature fluctuations are attenuated by the medium behind the lining, and the more obvious the blocking effect of the grout on the heat conduction path.

[0030] It should be noted that the conductivity sensing unit is located at the monitoring position behind the lining and is used to obtain the electrical conduction characteristics of the medium behind the lining under preset excitation conditions. The seepage conductivity is calculated by applying a stable potential difference across the monitoring medium and measuring the corresponding conduction current. The temperature sensing unit is located in the near-field region of the lining surface and is used to continuously collect the lining surface temperature data according to a preset sampling period to form the lining surface temperature time series information.

[0031] After obtaining the time series of the lining surface temperature, the first time derivative of the lining surface temperature is calculated to obtain the rate of temperature change, as expressed below: ; in, For the rate of temperature change, For a moment The collected surface temperature of the lining. For a moment The collected surface temperature of the lining. For a moment and time The time interval.

[0032] The corresponding rate of change of the ambient reference temperature is obtained within the time interval. Based on this, the temperature hysteresis coefficient is defined as: ; in, The temperature hysteresis coefficient, For the rate of temperature change, For the rate of change of ambient reference temperature, This is a preset feature to prevent small positive numbers with a denominator of zero.

[0033] The temperature hysteresis coefficient is used to quantify the degree of lag in the response of the lining surface temperature to changes in ambient temperature. Its value ranges from 0 to 1. The larger the temperature hysteresis coefficient, the slower the response of the lining surface temperature to changes in external temperature, indicating that the heat conduction path of the medium behind the lining is blocked, and the grouting body is densely filled with low porosity. The smaller the temperature hysteresis coefficient, the more synchronous the temperature response, indicating that there is a continuous cavity or water channel behind the lining, and the heat transfer efficiency is high.

[0034] It should be noted that the rate of change of the ambient reference temperature is used to characterize the intensity of the change in the external temperature field, which is unaffected by the medium behind the lining, within the same monitoring time interval. Specifically, the ambient surface temperature is acquired by an ambient temperature sensing unit deployed at a location outside the tunnel where it is not in contact with the lining, and its sampling time interval is consistent with that of the lining surface temperature. The corresponding rate of change of the ambient reference temperature is obtained by performing a first-order time difference operation on the continuously acquired time series of ambient surface temperatures.

[0035] The seepage conductivity and temperature hysteresis coefficient were normalized to obtain normalized seepage conductivity and normalized temperature hysteresis coefficient, and the grouting sealing characteristics were constructed, defined as follows: ; in, Features of grouting and sealing This is the normalized temperature hysteresis coefficient. To normalize the percolation conductivity, It is a preset positive constant used to prevent the denominator from approaching zero.

[0036] Grouting sealing characteristics are used to quantify the comprehensive sealing effect of the grout in both hydraulic conductivity and thermal conduction. The larger the value, the stronger the thermal hysteresis capacity under unit seepage conductivity conditions, indicating that the grouting sealing is more dense and complete. The smaller the value, the stronger the seepage conductivity or the weaker the thermal hysteresis effect, and the lower the integrity of the grouting sealing.

[0037] The grouting and sealing characteristics are compared with the preset sealing judgment threshold: When the grouting and sealing characteristics are lower than the sealing judgment threshold, it indicates that the delineated zone shows a trend of weakened grouting and sealing capacity, that is, there is an abnormal change in at least one dimension of hydraulic conductivity or thermal conduction blocking capacity, indicating that the sealing integrity of the grout body for potential seepage channels or voids may deteriorate. Based on this, the delineated zones that meet the above conditions are screened and marked to form marked delineated zones. The marked delineated zones are used to indicate candidate areas with abnormal grouting and sealing conditions, and are then passed to the cavity discrimination module as key analysis objects in the subsequent analysis.

[0038] When the grouting and sealing characteristics are not lower than the sealing judgment threshold, it indicates that the grouting and sealing of the designated area is in a stable state, and its seepage conduction capacity and heat conduction blocking capacity have not shown significant abnormal deviations relative to the historical benchmark. The grouting body still effectively seals the potential voids or seepage channels behind the lining.

[0039] For designated zones where the grouting and sealing characteristics are not lower than the sealing judgment threshold, the sealing assessment module determines them as zones in a stable sealing state, does not perform marking processing on them, and maintains the regular monitoring strategy, thereby avoiding misidentification of inherent structural discontinuities formed by historical grouting maintenance as new risk sources.

[0040] It should be noted that the threshold for determining grouting is based on historical operational data and zonal statistical characteristics. Specifically, historical grouting and grouting characteristic data of the corresponding designated zone under stable operating conditions are retrieved, a statistical distribution interval of the grouting and grouting characteristics is constructed, and a statistical quantity representing the lower limit level under normal grouting conditions is calculated based on this statistical distribution as the grouting determination threshold.

[0041] In the cavity discrimination module, images of the lining surface corresponding to the marked and delineated zones are acquired, and the number of wet spots appearing on the lining surface is detected and counted. A wet spot refers to a localized area of ​​high humidity or visible watermarks formed on the lining surface, caused by water seepage or moisture migration from behind the lining. Based on the characteristics of reduced local reflectivity and color change exhibited by wet spots on the lining surface, a combination of threshold segmentation and connected component analysis is used to identify high-humidity areas in the lining surface image. False wet spot areas caused by stains, shadows, or differences in surface materials are removed through morphological processing. Finally, the wet spots that pass the discrimination are counted to obtain the number of wet spots in the marked and delineated zones.

[0042] The number of wet spots is used to characterize the spatial dispersion of water activity behind the lining. The larger the value, the more seepage channels or cavities are connected to the lining surface, and the wider the range of water activity. The smaller the value, the more concentrated or restricted the water activity, and the fewer seepage channels are behind the lining.

[0043] After obtaining the number of wet spots, the cavity discrimination module incorporates the grouting reference level output by the benchmark construction module to correct the grouting and sealing features: Specifically, to reduce the influence of historical grouting background on the judgment of the current sealing status, the cavity discrimination module performs linear reduction correction on the grouting sealing features, defining the corrected grouting sealing features as follows: ; in, To correct the grouting and sealing characteristics, This is a characteristic of grouting and sealing. This serves as a reference layer for grouting.

[0044] When the grouting reference level approaches 0, it indicates that the influence of historical grouting is negligible, and the modified grouting sealing characteristics are close to the original grouting sealing characteristics. When the grouting reference level approaches 1, it indicates that the historical grouting background is dominant, and the modified grouting sealing characteristics are significantly reduced, in order to avoid misjudging the structural non-uniformity left over from historical grouting as new risks.

[0045] To eliminate the impact of differences in the area of ​​different zones on the comparability of wet spot quantity, the wet spot quantity is normalized by area, and the wet spot density is defined as the ratio of the wet spot quantity to the lining surface area of ​​the corresponding marked zone.

[0046] Wet spot density characterizes the number of water activity connectivity points per unit area. The larger the value, the more seepage channels or cavities formed behind the lining are connected to the lining surface.

[0047] To jointly determine the wet spot density and the modified grouting and sealing characteristics, the wet spot density is normalized to obtain the normalized wet spot density, which has a value range of 0 to 1.

[0048] After obtaining the modified grouting and sealing characteristics and the normalized wet spot density, the cavity discrimination module constructs a cavity activation discrimination index to determine the risk of cavity reactivation, which is defined as: ; in, The cavity activation discriminant index, To normalize the wet spot density, To correct the grouting and sealing characteristics, and The preset exponential coefficient.

[0049] The cavity activation discriminant index reflects the intensity level of water activity diffusion under the condition of unit effective plugging capacity. The larger the value, the more the water activity has been spatially distributed in multiple points under the condition of insufficient plugging capacity, which is more consistent with the characteristics of cavity re-establishment and activation.

[0050] The cavity activation discrimination index is compared with the preset cavity activation judgment threshold: When the cavity activation discrimination index is greater than or equal to the cavity activation judgment threshold, it is determined that there is a risk of cavity reactivation in the corresponding marked area, triggering a cavity regeneration prompt. When the cavity activation discrimination index is less than the cavity activation judgment threshold, it is determined that there is no risk of cavity reactivation in the corresponding marked area, and cavity regeneration prompt is not triggered.

[0051] The cavity regeneration indicator is a risk indication information output by the cavity discrimination module. It is used to characterize the possibility that the corresponding delineated area has the possibility of cavity re-establishment and entering the activation state. It indicates that the delineated area has the key characteristics of cavity regeneration under the coupled conditions of water activity diffusion and grouting sealing capacity decay, and should be included in the scope of key attention and further verification.

[0052] It should be noted that the preset index coefficients are used to adjust the weights of normalized wet spot density and modified grouting and plugging characteristics in the cavity activation discrimination index, reflecting the relative impact of water activity diffusion and plugging capacity decay on the cavity activation risk. The specific setting process is based on historical monitoring data and confirmed cavity evolution examples: First, normalized wet spot density, modified grouting and plugging characteristics, and actual cavity status judgment results corresponding to multiple delineated zones at different operational stages are collected to construct a sample dataset; then, the values ​​of α and β are determined by minimizing the discrimination error; the cavity activation judgment threshold is used to distinguish whether the marked delineated zones have entered a high-risk state of cavity reactivation, and its setting is based on statistical distribution. Specifically, the time series of the cavity activation discrimination index corresponding to each marked delineated zone during historical operation under the condition that no cavity regeneration event has occurred is retrieved, the statistical distribution interval of the index is constructed, and a statistical quantity that can characterize the upper limit of normal fluctuations is selected as the cavity activation judgment threshold, such as the mean-weighted standard deviation.

[0053] Finally, it should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0054] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0055] In this document, the singular forms “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that terms such as “comprising / including” or “having” specify the presence of the stated features, integrals, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integrals, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0056] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0057] The above description of the disclosed embodiments will enable those skilled in the art to make or use various modifications to these embodiments. It will be readily apparent to those skilled in the art that the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A tunnel structure monitoring system based on multi-source sensing, characterized in that: It includes a disconnection identification module, a baseline construction module, a plugging evaluation module, and a cavity identification module. The functions of each module are as follows: The disconnection identification module acquires the grouting maintenance information of the lining area to be tested, and divides the lining area to be tested into zones based on the grouting maintenance information. When a vehicle enters a zone, the module collects the structural vibration data of the zone and generates a transmission disconnection trend, which is then transmitted to the baseline construction module. The baseline construction module is used to access the historical database to retrieve the peak grouting pressure of the designated area, use the peak grouting pressure to perform abrupt change screening analysis to generate the grouting solidification index, and combine the grouting solidification index with the transmission discontinuity trend to locate the grouting reference level of the designated area, and then pass the grouting reference level into the cavity discrimination module. The sealing assessment module is used to collect the seepage conductivity and lining surface temperature of each designated zone, calculate the temperature hysteresis coefficient based on the lining surface temperature, assess the grouting sealing characteristics in combination with the seepage conductivity, use the grouting sealing characteristics to screen and mark the designated zones, and then transmit the marked designated zones to the cavity discrimination module. The cavity discrimination module is used to detect the number of wet spots in the marked and delineated areas, correct the grouting and sealing characteristics according to the grouting reference level, and determine whether to trigger a cavity regeneration prompt based on the number of wet spots.

2. The tunnel structure monitoring system based on multi-source sensing according to claim 1, characterized in that: In the disconnection identification module, grouting maintenance information of the lining area to be tested is obtained from the historical database, including the type of grouting material and the range of grouting locations; Among them, the grouting material type refers to the type of grout in the maintenance batch; the grouting location range refers to the spatial range of the grouting operation in the tunnel lining; Based on the grouting location range, the grouting action range corresponding to the maintenance batch is extracted. Using the grouting action range as the basic boundary, the lining area to be tested is divided into multiple initial sections. Furthermore, the consistency of grouting material type is judged for initial sections that are adjacent or have overlapping areas, resulting in different delineation zones.

3. The tunnel structure monitoring system based on multi-source sensing according to claim 1, characterized in that: In the disconnection identification module, when a vehicle enters a designated zone, the moment when the vehicle enters the boundary of the designated zone is taken as the entry time. Within a preset entry acquisition time after the entry time, vibration response signals are acquired by an acceleration sensor, and the vibration acceleration amplitude sequence in the vibration response signal is extracted as the structural vibration data on the entry side. The departure time is defined as the moment when the vehicle approaches the exit boundary of the designated zone and leaves the designated zone. Within the preset departure acquisition time before the departure time, vibration response signals are acquired and vibration acceleration amplitude sequences are extracted as structural vibration data on the exit side.

4. A tunnel structure monitoring system based on multi-source sensing according to claim 3, characterized in that: In the disconnection identification module, the average values ​​of the structural vibration data on the entry side and the exit side are calculated to obtain the average vibration amplitude on the entry side and the average vibration amplitude on the exit side. The vibration transmission ratio is obtained by calculating the ratio of the average amplitude of the vibration on the inlet side to the average amplitude of the vibration on the outlet side. Within a preset statistical period, the vibration transmission ratios of each defined zone are recorded in chronological order, and the vibration transmission ratios of two adjacent zones are compared to screen for events that exacerbate the disconnection. The transmission disconnection trend is calculated based on the number of disconnection events within a preset statistical period.

5. A tunnel structure monitoring system based on multi-source sensing according to claim 1, characterized in that: In the baseline construction module, the historical database is accessed to retrieve the peak grouting pressure of the designated zone; The peak grouting pressure was used for abrupt change screening analysis. Specifically, the peak grouting pressures within the same defined zone were arranged in chronological order to form a grouting peak pressure sequence. The difference between adjacent grouting peak pressures is calculated to obtain the peak pressure change amplitude. The peak pressure change amplitude is compared with the preset peak pressure change threshold to screen out grouting pressure abrupt events. The grouting pressure abrupt events in the grouting peak pressure sequence are statistically analyzed to obtain the number of grouting pressure abrupt events, and the grouting solidification index is calculated based on the number of grouting pressure abrupt events. The grouting curing index and the transmission discontinuity trend were standardized to obtain the grouting curing coefficient and the transmission discontinuity coefficient, respectively. The grouting reference layer is calculated based on the grouting curing coefficient and the transmission discontinuity coefficient.

6. The tunnel structure monitoring system based on multi-source sensing according to claim 1, characterized in that: In the sealing assessment module, the seepage conductivity and lining surface temperature of each designated zone are collected synchronously within a preset monitoring period and a time series is formed. The seepage conductivity is obtained by the conductivity sensing unit, and its physical meaning is the ability of water to pass through the lining-surrounding rock system under a unit potential gradient. The surface temperature of the lining is continuously collected by the temperature sensing unit, reflecting the thermal response state of the lining structure under the combined effects of ambient temperature disturbance and internal medium heat conduction. After obtaining the time series of the lining surface temperature, the first time derivative of the lining surface temperature is calculated to obtain the rate of temperature change. Within the same time interval corresponding to the time series, the rate of change of the environmental reference temperature is obtained, and the temperature hysteresis coefficient is defined as: ; in, The temperature hysteresis coefficient, For the rate of temperature change, For the rate of change of ambient reference temperature, It is a preset small positive number.

7. A tunnel structure monitoring system based on multi-source sensing according to claim 6, characterized in that: In the grouting assessment module, the seepage conductivity and temperature hysteresis coefficient are normalized to obtain normalized seepage conductivity and normalized temperature hysteresis coefficient, and grouting grouting characteristics are constructed: ; in, This is a characteristic of grouting and sealing. This is the normalized temperature hysteresis coefficient. To normalize the percolation conductivity, It is a preset positive constant; When the grouting and sealing characteristics are lower than the preset sealing judgment threshold, the determination is to screen and mark the delineated areas to form marked delineated areas; When the grouting and sealing characteristics are not lower than the preset sealing judgment threshold, the zone is determined to be a stable sealing state zone and no marking process is performed.

8. A tunnel structure monitoring system based on multi-source sensing according to claim 7, characterized in that: In the cavity discrimination module, the lining surface image corresponding to the marked and delineated partition is obtained, and the number of wet spots appearing on the lining surface is detected and counted. By introducing the grouting reference level output by the baseline construction module, a linear reduction correction is performed on the grouting sealing features, and the corrected grouting sealing features are defined as follows: ; in, To correct the grouting and sealing characteristics, This is a characteristic of grouting and sealing. This serves as a reference layer for grouting. The number of wet spots is normalized by area, and the wet spot density is defined as the ratio of the number of wet spots to the lining surface area of ​​the corresponding marked partition. The wet spot density is normalized to obtain the normalized wet spot density.

9. A tunnel structure monitoring system based on multi-source sensing according to claim 8, characterized in that: In the cavity discrimination module, after obtaining the modified grouting and sealing characteristics and the normalized wet spot density, a cavity activation discrimination index is constructed: ; in, The cavity activation discriminant index, To normalize the wet spot density, To correct the grouting and sealing characteristics, and The preset exponential coefficient; When the cavity activation discrimination index is greater than or equal to the cavity activation judgment threshold, it is determined that there is a risk of cavity reactivation in the corresponding marked area, triggering a cavity regeneration prompt. When the cavity activation discrimination index is less than the cavity activation judgment threshold, it is determined that there is no risk of cavity reactivation in the corresponding marked area, and cavity regeneration prompt is not triggered. The cavity regeneration prompt is a risk indication information output by the cavity discrimination module, used to characterize the possibility that a cavity in the corresponding defined partition may be re-established and enter an active state.

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