Method and device for tunnel advanced geological prediction and safety monitoring based on optical fiber sensing

Abstract

This invention discloses a method and device for advanced geological prediction and safety monitoring of tunnels based on fiber optic sensing. The method includes: S1, deploying sensing optical fibers in the excavated section of the tunnel to be monitored; S2, demodulating the strain and strain rate of the soil and rock mass along the route of the sensing fibers, obtaining the deformation and strain distribution of the soil and rock mass from the deformation strain, and extracting site vibration information from the site vibration strain rate; S3, analyzing the site vibration information to obtain the measured surface wave dispersion curve, and deducing the target three-dimensional geological model; S4, advanced geological prediction of the tunnel; S5, tunnel construction safety monitoring; S6, post-construction safety monitoring of the tunnel. This invention uses fiber optic sensing technology to continuously monitor the deformation strain of the soil and rock mass and the site vibration strain rate throughout the entire construction and service life of the tunnel. The data obtained at different times can be used for advanced geological prediction, tunnel construction safety monitoring, and post-construction safety monitoring of the tunnel, meeting various safety monitoring needs of tunnel engineering.

Description

Technical Field

[0001] This invention relates to the field of tunnel advanced geological prediction and safety monitoring technology, and more specifically, to a method and device for tunnel advanced geological prediction and safety monitoring based on fiber optic sensing. Background Technology

[0002] Advanced geological forecasting for tunnels involves assessing and predicting the geological conditions of the rock and soil masses in front of and around the tunnel face during tunnel excavation. Data is obtained through various advanced geological forecasting methods to evaluate the structural characteristics, lithological features, and groundwater distribution of the rock and soil masses ahead of the tunnel. This allows for early prediction and warning of potential construction difficulties and geological problems, providing a scientific basis for tunnel excavation and ultimately ensuring construction safety and project quality.

[0003] Commonly used methods for advanced geological prediction of tunnels include advanced drilling, electrical methods, electromagnetic methods, and seismic wave methods. Among these, the seismic wave method is one of the mainstream methods currently in use. This method utilizes the propagation characteristics of seismic waves in underground rock and soil masses. By analyzing the propagation velocity and attenuation of seismic waves, it infers geological information such as the lithology, soil properties, structural characteristics, fissure and karst cave development, and groundwater distribution of the rock and soil mass. Currently, traditional seismic wave sensing systems mainly consist of seismographs, geophones, and data processing systems. However, due to limitations in instruments and power supply, the deployment and maintenance costs of traditional seismic wave sensing systems are high, the data acquisition range is limited, and it is difficult to achieve high-density real-time monitoring and early warning.

[0004] Distributed acoustic wave sensing technology, a branch of fiber optic sensing, was proposed in the 1990s and has been increasingly applied in the field of geological and seismic monitoring in recent years. This technology uses optical fibers as sensors, measuring the strain rate of the fiber by monitoring changes in the phase information of coherent Rayleigh scattered light, thereby sensing underground vibrations. By analyzing the time difference in the reception of Rayleigh scattered light, the location of the buried optical fiber corresponding to the vibration information is determined, thus monitoring and analyzing the underground structure of rock and soil and other geological conditions. Currently, the sensing length of distributed acoustic wave sensing technology can extend to tens of thousands of meters, the vibration detection bandwidth can reach tens of thousands of hertz, and the array spacing can be flexibly adjusted, with a spatial resolution as low as one meter. In the field of seismic monitoring, distributed acoustic wave sensing technology can sense underground vibration signals in real time and continuously. Compared with traditional seismic wave sensing systems, distributed acoustic wave sensing technology has advantages such as wide coverage, high spatial resolution, and good real-time performance, enabling better real-time monitoring of underground structures.

[0005] Meanwhile, Brillouin scattering-type fiber optic sensing technology in fiber optic sensing can measure the strain of the fiber by monitoring the frequency shift of the Brillouin scattered light in the fiber, and analyze the abnormal deformation of the rock and soil around the tunnel wall. It is worth noting that the phase change of Rayleigh scattered light in distributed acoustic wave sensing technology and the frequency shift of Brillouin scattered light in Brillouin scattering-type fiber optic sensing technology are both affected by the ambient temperature. However, Raman scattering-type fiber optic sensing technology in fiber optic sensing can calculate the ambient temperature by the ratio of the intensity of Stokes light and anti-Stokes light. Therefore, when monitoring strain and strain rate based on Brillouin scattering and Rayleigh scattering, the ambient temperature can be determined based on Raman scattering, and the influence of the ambient temperature can be corrected and eliminated.

[0006] Based on this, the present invention proposes a method and device for advanced geological prediction and safety monitoring of tunnels based on fiber optic sensing. The method utilizes a fiber optic sensing system to acquire strain and strain rate information at various points along the fiber optic cable arrangement in the tunnel to be tested, analyzes the underground structure, predicts the characteristics and changes of the geological conditions ahead of the tunnel, performs advanced geological prediction for tunnel excavation, monitors tunnel construction safety and post-construction safety, and provides timely early warning of potential safety problems in the tunnel. Summary of the Invention

[0007] The purpose of this invention is to provide a method and device for advanced geological prediction and safety monitoring of tunnels based on fiber optic sensing, so as to overcome the defects of the existing technology.

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

[0009] A method for advanced geological prediction and safety monitoring of tunnels based on fiber optic sensing includes the following steps:

[0010] S1. Before or during the lining of the excavated section of the tunnel to be tested, sensor optical fibers are arranged on the sidewalls, bottom plate, top plate and working face of the excavated section of the tunnel.

[0011] S2. During tunnel construction, for two adjacent tunnel faces with fiber optic sensing, the time interval between the start of fiber optic sensing at the first face and the start of fiber optic sensing at the second face is defined as a monitoring cycle. During tunnel operation, a natural month is defined as a monitoring cycle. Within each monitoring cycle, equal time intervals are divided into multiple monitoring periods. During different monitoring periods within different monitoring cycles, the fiber optic demodulator emits laser pulses to the fiber optic sensing and receives the Brillouin scattered light propagating backward from the sensing. The demodulated optical signal is used to obtain the frequency shift of the Brillouin scattered light, thus obtaining strain information at various points along the fiber optic sensing route. This strain information is then categorized into soil and rock deformation. Strain and field vibration strain are obtained from the deformation strain of the soil and rock mass, which gives the deformation strain distribution of the soil and rock mass at the location of the sensing fiber under each monitoring period in each monitoring cycle. Under different monitoring periods in different monitoring cycles, the fiber optic demodulator emits laser pulses to the sensing fiber and receives the Rayleigh scattered light propagating backward from the sensing fiber. The demodulated optical signal obtains the phase change of the Rayleigh scattered light and obtains the strain rate information at each point along the line of the sensing fiber. The strain rate information is divided into soil and rock deformation strain rate and field vibration strain rate. Based on the frequency and time characteristics of the field vibration strain rate under each monitoring period in each monitoring cycle, the field vibration information of the corresponding monitoring cycle and monitoring period is extracted.

[0012] S3. During each monitoring period of each monitoring cycle, based on regional geological reports, regional geological maps, and previous exploration data, obtain the main distribution of soil and rock masses along the tunnel to construct an initial three-dimensional geological model. Then, based on the shear modulus G and density ρ of the soil and rock masses, use the formula... The shear wave velocity *v* of the soil and rock mass is calculated to obtain the shear wave velocity structure of the initial three-dimensional geological model. The propagation of surface waves in the initial three-dimensional geological model is simulated using the finite element method, and the simulated surface wave dispersion curve is obtained through numerical simulation. At each monitoring period under each monitoring cycle, the site vibration information measured by the fiber optic demodulator is filtered to distinguish vibration information generated by different vibration events. Vibration information with high signal-to-noise ratio is extracted, and the extracted vibration information is processed using frequency-time analysis to obtain the measured surface wave dispersion curve. The difference between the simulated and measured surface wave dispersion curves is compared, and an iterative optimization algorithm is used to continuously adjust the geological characteristics of the soil and rock mass in the initial three-dimensional geological model until the error between the simulated and measured surface wave dispersion curves at the same monitoring period under the same monitoring cycle meets the site monitoring accuracy requirements. The adjusted initial three-dimensional geological model is then determined as the target three-dimensional geological model for the corresponding monitoring cycle and monitoring period.

[0013] S4. During the current monitoring period when the sensing fiber optic cables are first deployed at the tunnel face, based on the target 3D geological model obtained during the monitoring period before the continued excavation at the tunnel face, the geological characteristics of the rock and soil in front of the tunnel face are obtained, and an advanced geological forecast report is issued. The advanced geological forecast report is updated in a timely manner based on the target 3D geological model obtained during the monitoring period after the continued excavation at the tunnel face. The stability of the rock and soil in front of the tunnel face is analyzed based on the target 3D geological model obtained in the current monitoring period, and the stability characteristic value of the rock and soil structure is calculated. When the stability characteristic value of the rock and soil structure in front of the tunnel face exceeds the warning threshold of the stability characteristic value of the rock and soil structure, an automatic alarm is triggered, and handling suggestions are proposed in light of engineering problem examples.

[0014] S5. During tunnel construction, based on the site vibration information acquired during each monitoring period under each monitoring cycle, tunnel construction noise and vibration data are extracted to obtain the daily construction time, frequency, and progress. The monitored construction time, frequency, and progress are compared with the construction plan and current specifications to assess the compliance of the construction. Based on the target three-dimensional geological model acquired during each monitoring period under each monitoring cycle, the stability of the rock and soil mass around the tunnel wall and in front of the tunnel face is analyzed. The stability characteristic value of the rock and soil mass structure and the difference between the stability characteristic values ​​of the rock and soil mass structure are calculated. When the stability characteristic value of the rock and soil mass structure exceeds the stability characteristic value of the rock and soil mass structure, an early warning is issued. The system automatically alarms when the difference in the characteristic values ​​of the stability of the soil and rock structure exceeds the warning threshold, and provides handling suggestions based on engineering problem examples. Based on the deformation and strain data of the soil and rock mass acquired during each monitoring period under each monitoring cycle, the system obtains the deformation status of the soil and rock mass surrounding the tunnel wall, calculates the characteristic values ​​of soil and rock deformation and strain, and the difference between these characteristic values. It automatically alarms when the characteristic value of soil and rock deformation and strain exceeds the warning threshold, or when the difference between these characteristic values ​​exceeds the warning threshold, and provides handling suggestions based on engineering problem examples.

[0015] S6. During tunnel operation, the stability of the surrounding rock and soil mass is analyzed based on the target three-dimensional geological model obtained during each monitoring period under each monitoring cycle. The stability characteristic value and the difference between the stability characteristic values ​​of the rock and soil mass are calculated. An automatic alarm is triggered when the stability characteristic value of the rock and soil mass exceeds the warning threshold, or when the difference between the stability characteristic values ​​of the rock and soil mass exceeds the warning threshold for the difference between the stability characteristic values ​​of the rock and soil mass. Treatment suggestions are also provided based on engineering problem examples. Furthermore, the deformation of the surrounding rock and soil mass is obtained based on the deformation and strain data of the rock and soil mass obtained during each monitoring period under each monitoring cycle. The deformation and strain characteristic value and the difference between the deformation and strain characteristic values ​​of the rock and soil mass are calculated. An automatic alarm is triggered when the deformation and strain characteristic value of the rock and soil mass exceeds the warning threshold, or when the difference between the deformation and strain characteristic values ​​of the rock and soil mass exceeds the warning threshold for the difference between the deformation and strain characteristic values ​​of the rock and soil mass. Treatment suggestions are also provided based on engineering problem examples.

[0016] Furthermore, the principle for arranging the sensing optical fibers in step S1 is as follows: the sensing optical fibers are continuously laid out on the tunnel sidewalls, bottom plate, and top plate, while the sensing optical fibers are intermittently laid out on the tunnel face.

[0017] Further, the specific steps in step S1 of arranging sensing optical fibers in the sidewalls, bottom slab, top slab, and working face of the excavated section of the tunnel include: excavating small trenches in the sidewalls, bottom slab, top slab, and working face of the excavated section of the tunnel, burying the sensing optical fibers inside the trenches, and backfilling and fixing them with soil or construction grout; the sensing optical fibers arranged in the sidewalls, bottom slab, and top slab of the tunnel are connected to an optical fiber demodulator at one end at the tunnel excavation inlet, and a free section is left at the end near the tunnel excavation working face. As the tunnel is continuously excavated, the free section of the optical fiber is continuously arranged along the newly excavated section in the tunnel; the sensing optical fibers arranged in the tunnel working face are connected to an optical fiber demodulator at one end, and are directly removed after monitoring as the tunnel is excavated. As the tunnel is excavated, the sensing optical fibers are re-arranged in the new working face to be monitored.

[0018] Further, in step S2, the deformation strain of the rock and soil body is the strain generated by the internal deformation of the rock and soil body, the site vibration strain is the strain generated by the rock and soil body sensing the site vibration signal, the deformation strain rate of the rock and soil body is the strain rate generated by the internal deformation of the rock and soil body, and the site vibration strain rate is the strain rate generated by the rock and soil body sensing the site vibration signal; the sources that excite the site vibration signal include construction noise, environmental noise, and man-made earthquakes, and man-made earthquakes include various types such as heavy hammer strikes and gunpowder explosions.

[0019] Furthermore, the geological characteristics of the rock and soil mass in step S3 include lithological distribution, porosity, development of fissures and karst caves, and groundwater distribution. After the tunnel is excavated, the actual geological characteristics of the newly excavated section are added to the initial three-dimensional geological model of the latest monitoring period under the current monitoring cycle, and the resulting new three-dimensional geological model is set as the initial three-dimensional geological model of the next adjacent monitoring cycle and monitoring period.

[0020] During the current monitoring cycle, the actual geological characteristics of the newly excavated section of the tunnel are compared with the geological characteristics reflected by the target three-dimensional geological model obtained through deduction. The differences between the two are analyzed, the errors of the target three-dimensional geological model are identified, and the parameters of the iterative optimization algorithm are improved. In the next monitoring cycle, the improved iterative optimization algorithm is used to adjust the initial three-dimensional geological model.

[0021] Furthermore, step S5, which involves extracting tunnel construction noise vibration data based on site vibration information acquired during each monitoring period under each monitoring cycle, to obtain the daily construction time, frequency, and progress, specifically includes: analyzing the extracted tunnel construction noise vibration data; obtaining the start and end times and working periods of daily construction based on the time characteristics of noise vibration; obtaining the working frequencies of different construction equipment and procedures based on the frequency distribution of noise vibration and the noise frequency characteristics generated by different types of construction equipment; and determining the progress of construction based on the intensity, frequency changes, and vibration location of noise vibration.

[0022] Furthermore, in steps S4, S5, and S6, the stability characteristic values ​​of the rock and soil mass structure include at least the length of crack development, the size of karst cave development, the width of fault development, the groundwater level, the range of weak rock strata development, and the range of unstable areas; in steps S5 and S6, the deformation and strain characteristic values ​​of the rock and soil mass include at least daily strain, monthly strain, and cumulative strain; the difference in the stability characteristic values ​​of the rock and soil mass structure is the maximum difference between the stability characteristic values ​​of the rock and soil mass structure in the latest monitoring period under the current monitoring cycle and the stability characteristic values ​​of the rock and soil mass structure in the monitoring period under other previous monitoring cycles; the difference in the deformation and strain characteristic values ​​of the rock and soil mass is the maximum difference between the deformation and strain characteristic values ​​of the rock and soil mass in the latest monitoring period under the current monitoring cycle and the deformation and strain characteristic values ​​of the rock and soil mass in the monitoring period under other previous monitoring cycles; and different warning thresholds for the stability characteristic values ​​of the rock and soil mass structure, the difference in the stability characteristic values ​​of the rock and soil mass structure, the warning threshold for the deformation and strain characteristic values ​​of the rock and soil mass, and the warning threshold for the difference in the deformation and strain characteristic values ​​of the rock and soil mass are preset for the rock and soil mass located at different locations in the tunnel according to current specifications and construction requirements.

[0023] Furthermore, throughout the entire construction and service life of the tunnel, historical and real-time data are analyzed regularly. The structural stability and deformation strain characteristics of the surrounding rock and soil of the tunnel wall are compared with those of each monitoring period under each monitoring cycle. Time periods with obvious anomalies and abnormal trends are identified. The construction and natural factors that caused the anomalies and abnormal trends are analyzed, and monitoring reports are generated to facilitate improvements and prevention in the subsequent construction and use of the tunnel.

[0024] This invention provides an apparatus for implementing the aforementioned method for advanced geological prediction and safety monitoring of tunnels based on fiber optic sensing. The apparatus includes a sensing fiber, a fiber optic demodulator, and a central processing station. The fiber optic demodulator emits laser pulses into the sensing fiber and receives Brillouin scattered light, Rayleigh scattered light, and Raman scattered light propagating backwards from the sensing fiber. It demodulates the optical signals to obtain the frequency shift of the Brillouin scattered light, the phase change of the Rayleigh scattered light, and the intensity of the Raman scattered light, thereby obtaining strain information and strain rate information at various points along the sensing fiber's arrangement. The central processing station includes:

[0025] The data receiving and processing module is used to divide the monitoring cycle and monitoring period, acquire the strain information and strain rate information of the rock and soil mass measured by the fiber optic integrated demodulator, distinguish the strain information into the deformation strain of the rock and soil mass and the site vibration strain, distinguish the strain rate information into the deformation strain rate of the rock and soil mass and the site vibration strain rate, extract the site vibration information from the site vibration strain rate, obtain the measured surface wave dispersion curve, and deduce the target three-dimensional geological model for each monitoring period under each monitoring cycle.

[0026] The tunnel advanced geological prediction module is used to obtain the geological characteristics of the rock and soil in front of the tunnel face based on the target three-dimensional geological model obtained in the current monitoring cycle, and generate an advanced geological prediction report.

[0027] The tunnel construction safety monitoring module is used to extract tunnel construction noise vibration data based on site vibration information obtained during tunnel construction, to obtain daily construction time, frequency and progress, in order to assess the standardization of tunnel construction; and to analyze the stability of the rock and soil around the tunnel wall and in front of the tunnel face based on the target three-dimensional geological model obtained from the site; and to obtain the deformation of the rock and soil around the tunnel wall based on the deformation strain of the rock and soil obtained from the site.

[0028] The tunnel construction safety monitoring module is used to analyze the stability of the rock and soil surrounding the tunnel wall during tunnel use based on the target three-dimensional geological model obtained from the site; and to obtain the deformation of the rock and soil surrounding the tunnel wall based on the deformation strain of the rock and soil obtained from the site.

[0029] The tunnel safety early warning module is used to automatically trigger an alarm during tunnel construction and use. Based on the monitoring results of the tunnel advanced geological prediction module, tunnel construction safety monitoring module, and tunnel post-construction safety monitoring module, the module triggers an alarm when the stability characteristic value of the rock and soil mass exceeds the early warning threshold, the deformation and strain characteristic value of the rock and soil mass exceeds the early warning threshold, or the difference between the stability characteristic values ​​of the rock and soil mass exceeds the early warning threshold, or the difference between the deformation and strain characteristic values ​​of the rock and soil mass exceeds the early warning threshold. The module analyzes the engineering geological problems of the tunnel rock and soil mass corresponding to the monitoring cycle and monitoring period corresponding to the automatic alarm and generates a report with suggestions for handling engineering problems.

[0030] Furthermore, the tunnel safety early warning module incorporates an engineering problem instance database. This database covers problems encountered during tunnel construction and use, along with corresponding handling methods. For automatically alarmed tunnel geotechnical problems, the module retrieves similar engineering instances from the database by analogy with the site's main geological conditions, tunnel excavation depth and burial conditions, and engineering geological problem types. Based on the handling methods and strategies in the most similar engineering instances, an engineering problem handling suggestion report is generated. The module also records in detail the engineering problems, handling methods, and handling effects of the monitored tunnels, and inputs these new records into the engineering problem instance database to continuously update and expand its capacity.

[0031] Compared with the prior art, the advantages of the present invention are as follows:

[0032] 1. This invention uses fiber optic sensing technology to continuously monitor the deformation and strain of the soil and rock mass and the site vibration strain rate during the entire construction and service period of the tunnel. The data obtained at different times can be used for tunnel advanced geological prediction, tunnel construction safety monitoring and tunnel post-construction safety monitoring, meeting the diverse needs of tunnel engineering safety monitoring.

[0033] 2. This invention uses optical fiber sensing to monitor site vibration. Compared with the traditional seismic wave method tunnel advanced geological prediction system, the optical fiber sensing-based tunnel advanced geological prediction system has the advantages of high resolution, long sensing distance, good continuity, and simple structure. It can be continuously deployed over a long sequence and a large area, making up for the problem of difficult deployment of traditional seismic wave sensing systems. It is well applicable to tunnel monitoring sites with long time intervals, large areas, and complex environments.

[0034] 3. This invention uses sensing optical fibers for advanced geological prediction and tunnel safety monitoring. Due to the advantages of optical fiber materials such as corrosion resistance, electromagnetic interference resistance, small size, light weight, flexibility and toughness, compared with other tunnel monitoring equipment and instruments that are susceptible to electromagnetic interference and have a large size, sensing optical fibers have stronger portability and embeddability, and can be applied to tunnels with various usage types, excavation methods and excavation sizes, making them highly operable.

[0035] 4. The sensing optical fiber used in this invention can be continuously deployed along the tunnel axis during tunnel excavation. After deployment, it can be connected to the optical fiber demodulator to monitor the tunnel at any time. It can achieve continuous monitoring of the entire length and cycle of the tunnel without moving it. Moreover, there is no need to retrieve the monitoring optical fiber after the monitoring period ends. It is simple to use and has low maintenance costs. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart of the tunnel advanced geological prediction and safety monitoring method based on fiber optic sensing in an embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram of a tunnel advanced geological prediction and safety monitoring device based on fiber optic sensing, as described in this embodiment of the invention.

[0039] Figure 3 This is a schematic diagram illustrating the application scenario of the tunnel advanced geological prediction and safety monitoring method based on fiber optic sensing in an embodiment of the present invention. Detailed Implementation

[0040] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0041] See Figure 1 As shown in the figure, this embodiment deploys a fiber optic sensing-based tunnel advanced geological prediction and safety monitoring device in a hydraulic tunnel constructed using the drill-and-blast method to conduct long-term monitoring of soil deformation and site vibration. The specific implementation steps are as follows:

[0042] Step S1, Device Setup: After the excavation length of the tunnel to be tested reaches 50m, small trenches are excavated on the sidewalls, floor, and face of the excavated section of the tunnel. The sensing optical fibers are buried inside the trenches and backfilled with construction grout to fix them. The sensing optical fibers deployed on the tunnel sidewalls and floor are connected to the fiber optic demodulator at one end near the tunnel excavation inlet, with a free section at the end near the tunnel face. The length of the free section is the remaining excavation length of the tunnel. As the tunnel is continuously excavated, the free section of the optical fiber is continuously deployed along the newly excavated section within the tunnel. The sensing optical fibers deployed at the tunnel face are arranged in a cross pattern, with one end connected to the fiber optic demodulator. After monitoring at this face, they can be directly removed as the tunnel is excavated. As the tunnel is excavated, the sensing optical fibers are re-deployed at the new face to be tested every 5m.

[0043] Step S2, Data Acquisition: During tunnel construction, for two adjacent tunnel faces with fiber optic sensing, the time interval from the start of fiber optic sensing at the previous face to the start of fiber optic sensing at the next face is defined as a monitoring cycle. During tunnel operation, a natural month is defined as a monitoring cycle. Within each monitoring cycle, starting from the beginning of the monitoring cycle, monitoring periods are divided into 8-hour intervals. After dividing into several monitoring periods, if the remaining time of the monitoring cycle is less than 8 hours, the remaining time is defined as a monitoring period. In different monitoring periods under different monitoring cycles, the fiber optic demodulator emits laser pulses to the fiber optic sensing and receives the Brillouin scattered light propagating backward from the fiber optic sensing. The demodulated optical signal is used to obtain the frequency shift of the Brillouin scattered light, thus obtaining the transmission signal. The strain information at each point along the fiber optic cable is used to distinguish between soil deformation strain and site vibration strain. The soil deformation strain is used to obtain the soil deformation strain distribution at the fiber optic cable location during each monitoring period under each monitoring cycle. During different monitoring periods under different monitoring cycles, the fiber optic demodulator emits laser pulses to the fiber optic cable and receives Rayleigh scattered light propagating backward from the fiber optic cable. The demodulated optical signal is used to obtain the phase change of the Rayleigh scattered light, thus obtaining the strain rate information at each point along the fiber optic cable. The strain rate information is distinguished between soil deformation strain rate and site vibration strain rate. Based on the frequency and time characteristics of the site vibration strain rate during each monitoring period under each monitoring cycle, the site vibration information for the corresponding monitoring cycle and monitoring period is extracted.

[0044] Step S3: Data Processing; During each monitoring period of each monitoring cycle, based on regional geological reports, regional geological maps, and previous exploration data, the main distribution of soil and rock masses along the tunnel is obtained, an initial three-dimensional geological model is constructed, and the shear modulus G and density ρ of the soil and rock masses are calculated using the formula... The shear wave velocity *v* of the soil and rock mass is calculated to obtain the shear wave velocity structure of the initial three-dimensional geological model. The finite element method is used to simulate the propagation of surface waves in the initial three-dimensional geological model, and the simulated surface wave dispersion curve is obtained through numerical simulation. At each monitoring period under each monitoring cycle, the site vibration information measured by the fiber optic demodulator is filtered to distinguish the vibration information generated by different vibration events. Vibration information with high signal-to-noise ratio is extracted from vibration events (construction noise, environmental noise), and the extracted vibration information is processed using the frequency-time analysis method to obtain the measured surface wave dispersion curve. The difference between the simulated surface wave dispersion curve and the actual surface wave dispersion curve is compared, and the geological characteristics of the soil and rock mass in the initial three-dimensional geological model are continuously adjusted using an iterative optimization algorithm, including lithology distribution, porosity, fissure and karst development, and groundwater distribution, until the error between the simulated surface wave dispersion curve and the actual surface wave dispersion curve in the same monitoring period under the same monitoring cycle meets the site monitoring accuracy requirements. The adjusted initial three-dimensional geological model is then determined as the target three-dimensional geological model for the corresponding monitoring cycle and monitoring period.

[0045] Algorithm optimization: In the current monitoring cycle, compare the actual geological characteristics of the newly excavated section of the tunnel with the geological characteristics reflected by the deduced target three-dimensional geological model, analyze the differences between the two, identify the errors of the target three-dimensional geological model, improve the iterative optimization algorithm parameters, and in the next monitoring cycle, use the improved iterative optimization algorithm to adjust the initial three-dimensional geological model.

[0046] Pre-set warning thresholds: Pre-set warning thresholds for soil and rock masses located at different locations in the tunnel, including warning thresholds for six structural stability characteristic values ​​of soil and rock masses and warning thresholds for the differences between the corresponding structural stability characteristic values ​​of soil and rock masses, such as fracture development length, karst cave development size, fault development width, groundwater level elevation, weak rock layer development range, and unstable area range. Pre-set warning thresholds for three deformation and strain characteristic values ​​of soil and rock masses and warning thresholds for the differences between the corresponding deformation and strain characteristic values ​​of soil and rock masses, such as daily strain, monthly strain, and cumulative strain.

[0047] Step S4: Advanced Geological Prediction of the Tunnel; During the current monitoring period when the sensing fiber optic cables are first deployed at the tunnel face, based on the target 3D geological model obtained during the monitoring period before the continued excavation at the tunnel face, the geological characteristics of the rock and soil mass in front of the tunnel face are obtained, and an advanced geological prediction report is issued. The advanced geological prediction report is updated in a timely manner based on the target 3D geological model obtained during the monitoring period after the continued excavation at the tunnel face. The stability of the rock and soil mass in front of the tunnel face is analyzed based on the target 3D geological model obtained in the current monitoring period, and the stability characteristic value of the rock and soil mass structure is calculated. When the stability characteristic value of the rock and soil mass structure in front of the tunnel face exceeds the warning threshold of the stability characteristic value of the rock and soil mass structure, an automatic alarm is triggered, and handling suggestions are proposed in light of engineering problem examples.

[0048] Step S5: Tunnel Construction Safety Monitoring; During tunnel construction, noise and vibration data are extracted from site vibration information acquired during each monitoring period under each monitoring cycle. Based on the temporal characteristics of noise and vibration, the start and end times and working hours of daily construction are obtained. Based on the frequency distribution of noise and vibration, combined with the noise frequency characteristics generated by different types of construction equipment, the working frequencies of different construction equipment and processes are obtained. Based on the intensity, frequency changes, and vibration location of noise and vibration, the progress of construction processes such as blasting and excavation is determined, resulting in the daily construction time, frequency, and progress. The monitored construction time, frequency, and progress are compared with the construction plan and current specifications to evaluate the compliance of the construction. Based on the target three-dimensional geological model obtained during each monitoring period under each monitoring cycle, the tunnel wall surroundings and the tunnel face are analyzed. The system assesses the stability of the soil and rock mass ahead, calculates the characteristic values ​​of soil and rock structure stability and their differences, and automatically alarms when either the characteristic value or the difference exceeds a warning threshold. It also provides handling suggestions based on engineering problem examples. Furthermore, it assesses the deformation and strain of the soil and rock mass surrounding the tunnel wall based on data from various monitoring periods within each monitoring cycle, calculates the characteristic values ​​and differences of soil and rock deformation and strain, and automatically alarms when either exceeds a warning threshold or the difference exceeds a warning threshold. Finally, it provides handling suggestions based on engineering problem examples.

[0049] Step S6: Post-construction safety monitoring of the tunnel; During the tunnel's operation, the stability of the surrounding rock and soil is analyzed based on the target three-dimensional geological model obtained during each monitoring period under each monitoring cycle. The stability characteristic value and the difference between the stability characteristic values ​​of the rock and soil are calculated. An automatic alarm is triggered when the stability characteristic value of the rock and soil exceeds the warning threshold, or when the difference between the stability characteristic values ​​of the rock and soil exceeds the warning threshold for the difference between the stability characteristic values ​​of the rock and soil. Treatment suggestions are then proposed based on engineering problem examples. The deformation of the surrounding rock and soil is obtained based on the deformation and strain of the rock and soil obtained during each monitoring period under each monitoring cycle. The deformation and strain characteristic value and the difference between the deformation and strain characteristic values ​​of the rock and soil are calculated. An automatic alarm is triggered when the deformation and strain characteristic value of the rock and soil exceeds the warning threshold, or when the difference between the deformation and strain characteristic values ​​of the rock and soil exceeds the warning threshold for the difference between the deformation and strain characteristic values ​​of the rock and soil. Treatment suggestions are then proposed based on engineering problem examples.

[0050] This embodiment also includes monitoring report generation; throughout the entire construction and use period of the tunnel, historical and real-time data are analyzed regularly, and the structural stability and deformation strain characteristics of the soil and rock surrounding the tunnel wall are compared with those of each monitoring period under each monitoring cycle. Time periods with obvious abnormal values ​​and trends are identified, and the construction and natural factors that caused the abnormal values ​​and trends are analyzed to generate monitoring reports for improvement and prevention in the subsequent construction and use of the tunnel.

[0051] This embodiment also includes database updates; detailed records of engineering problems, handling methods, and handling effects of the monitored tunnels are recorded, and these new records are entered into the engineering problem instance database to continuously update and expand the capacity of the engineering problem instance database.

[0052] See Figure 3 As shown, this invention provides an apparatus for implementing the aforementioned method for advanced geological prediction and safety monitoring of tunnels based on fiber optic sensing. The apparatus includes a sensing fiber, a fiber optic demodulator, and a central processing station. The fiber optic demodulator is used to emit laser pulses into the sensing fiber and receive Brillouin scattered light, Rayleigh scattered light, and Raman scattered light propagating backwards from the sensing fiber. The demodulated optical signal is used to obtain the frequency shift of the Brillouin scattered light, the phase change of the Rayleigh scattered light, and the intensity of the Raman scattered light, thereby obtaining strain information and strain rate information at various points along the sensing fiber's arrangement. The central processing station includes:

[0053] The data receiving and processing module is used to divide the monitoring cycle and monitoring period, acquire the strain information and strain rate information of the rock and soil mass measured by the fiber optic integrated demodulator, distinguish the strain information into the deformation strain of the rock and soil mass and the site vibration strain, distinguish the strain rate information into the deformation strain rate of the rock and soil mass and the site vibration strain rate, extract the site vibration information from the site vibration strain rate, obtain the measured surface wave dispersion curve, and deduce the target three-dimensional geological model for each monitoring period under each monitoring cycle.

[0054] The tunnel advanced geological prediction module is used to obtain the geological characteristics of the rock and soil in front of the tunnel face based on the target three-dimensional geological model obtained in the current monitoring cycle, and generate an advanced geological prediction report.

[0055] The tunnel construction safety monitoring module is used to extract tunnel construction noise vibration data based on site vibration information obtained during tunnel construction, to obtain daily construction time, frequency and progress, in order to assess the standardization of tunnel construction; and to analyze the stability of the rock and soil around the tunnel wall and in front of the tunnel face based on the target three-dimensional geological model obtained from the site; and to obtain the deformation of the rock and soil around the tunnel wall based on the deformation strain of the rock and soil obtained from the site.

[0056] The tunnel construction safety monitoring module is used to analyze the stability of the rock and soil surrounding the tunnel wall during tunnel use based on the target three-dimensional geological model obtained from the site; and to obtain the deformation of the rock and soil surrounding the tunnel wall based on the deformation strain of the rock and soil obtained from the site.

[0057] The tunnel safety early warning module is used to automatically trigger an alarm during tunnel construction and use. Based on the monitoring results of the tunnel advanced geological prediction module, tunnel construction safety monitoring module, and tunnel post-construction safety monitoring module, the module triggers an alarm when the stability characteristic value of the rock and soil mass exceeds the early warning threshold, the deformation and strain characteristic value of the rock and soil mass exceeds the early warning threshold, or the difference between the stability characteristic values ​​of the rock and soil mass exceeds the early warning threshold, or the difference between the deformation and strain characteristic values ​​of the rock and soil mass exceeds the early warning threshold. The module analyzes the engineering geological problems of the tunnel rock and soil mass corresponding to the monitoring cycle and monitoring period corresponding to the automatic alarm and generates a report with suggestions for handling engineering problems.

[0058] In this embodiment, the tunnel safety early warning module has a built-in engineering problem instance database. This database covers problems encountered during tunnel construction and use, along with corresponding handling methods. For automatically alarmed tunnel rock and soil engineering geological problems, the module retrieves similar engineering instances from the database by analogy with the main geological conditions of the site, the tunnel's excavation depth and burial conditions, and the type of engineering geological problem. Based on the handling methods and coping strategies in the most similar engineering instance, an engineering problem handling suggestion report is generated. The module also records in detail the engineering problems, handling methods, and handling effects of the monitored tunnels, and inputs these new records into the engineering problem instance database to continuously update and expand its capacity.

[0059] This invention employs fiber optic sensing technology to continuously monitor the deformation and strain of the soil and rock mass and the site vibration strain rate throughout the entire construction and service period of the tunnel. The data obtained at different times can be used for advanced geological forecasting of the tunnel, tunnel construction safety monitoring, and post-construction safety monitoring, thus meeting various tunnel engineering safety monitoring needs.

[0060] This invention uses optical fiber sensing to monitor site vibration. Compared with traditional seismic wave tunnel advanced geological prediction systems, the optical fiber sensing-based tunnel advanced geological prediction system has advantages such as high resolution, long sensing distance, good continuity, and simple structure. It can be continuously deployed over a long sequence and a large area, making up for the problem of difficult deployment of traditional seismic wave sensing systems. It is well applicable to tunnel monitoring sites with long time intervals, large areas, and complex environments.

[0061] This invention uses sensing optical fibers for advanced geological prediction and tunnel safety monitoring. Due to the advantages of optical fiber materials such as corrosion resistance, electromagnetic interference resistance, small size, light weight, flexibility and toughness, compared with other tunnel monitoring equipment and instruments that are susceptible to electromagnetic interference and have a large size, sensing optical fibers have stronger portability and embeddability, and can be applied to tunnels with various usage types, excavation methods and excavation sizes, making them highly operable.

[0062] The sensing optical fiber used in this invention can be continuously deployed along the tunnel axis as the tunnel is excavated. After deployment, it can be connected to the optical fiber demodulator to monitor the tunnel at any time. It can achieve continuous monitoring of the entire length and cycle of the tunnel without moving it. Moreover, there is no need to retrieve the monitoring optical fiber after the monitoring period ends. It is simple to use and has low maintenance costs.

[0063] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, the patent owner may make various modifications or alterations within the scope of the appended claims, and such modifications or alterations shall be within the scope of protection of the present invention as long as they do not exceed the scope of protection described in the claims.

Claims

1. An apparatus for implementing a method for advanced geological prediction and safety monitoring of tunnels based on fiber optic sensing, characterized in that, Methods for advanced geological prediction and safety monitoring of tunnels include the following steps: S1. Before or during the lining of the excavated section of the tunnel to be tested, sensor optical fibers are arranged on the sidewalls, bottom plate, top plate and working face of the excavated section of the tunnel. S2. During tunnel construction, for two adjacent tunnel faces with fiber optic sensing, the time interval between the start of fiber optic sensing at the first face and the start of fiber optic sensing at the second face is defined as a monitoring cycle. During tunnel operation, a natural month is defined as a monitoring cycle. Within each monitoring cycle, equal time intervals are divided into multiple monitoring periods. During different monitoring periods within different monitoring cycles, the fiber optic demodulator emits laser pulses to the fiber optic sensing and receives the Brillouin scattered light propagating backward from the sensing. The demodulated optical signal is used to obtain the frequency shift of the Brillouin scattered light, thus obtaining strain information at various points along the fiber optic sensing route. This strain information is then categorized into soil and rock deformation. Strain and field vibration strain are obtained from the deformation strain of the soil and rock mass, which gives the deformation strain distribution of the soil and rock mass at the location of the sensing fiber under each monitoring period in each monitoring cycle. Under different monitoring periods in different monitoring cycles, the fiber optic demodulator emits laser pulses to the sensing fiber and receives the Rayleigh scattered light propagating backward from the sensing fiber. The demodulated optical signal obtains the phase change of the Rayleigh scattered light and obtains the strain rate information at each point along the line of the sensing fiber. The strain rate information is divided into soil and rock deformation strain rate and field vibration strain rate. Based on the frequency and time characteristics of the field vibration strain rate under each monitoring period in each monitoring cycle, the field vibration information of the corresponding monitoring cycle and monitoring period is extracted. S3. During each monitoring period of each monitoring cycle, based on regional geological reports, regional geological maps, and previous exploration data, obtain the main distribution of soil and rock masses along the tunnel to construct an initial three-dimensional geological model. Then, based on the shear modulus G and density ρ of the soil and rock masses, use the formula... The shear wave velocity *v* of the soil and rock mass is calculated to obtain the shear wave velocity structure of the initial three-dimensional geological model. The propagation of surface waves in the initial three-dimensional geological model is simulated using the finite element method, and the simulated surface wave dispersion curve is obtained through numerical simulation. At each monitoring period under each monitoring cycle, the site vibration information measured by the fiber optic demodulator is filtered to distinguish vibration information generated by different vibration events. Vibration information with high signal-to-noise ratio is extracted, and the extracted vibration information is processed using frequency-time analysis to obtain the measured surface wave dispersion curve. The difference between the simulated and measured surface wave dispersion curves is compared, and an iterative optimization algorithm is used to continuously adjust the geological characteristics of the soil and rock mass in the initial three-dimensional geological model until the error between the simulated and measured surface wave dispersion curves at the same monitoring period under the same monitoring cycle meets the site monitoring accuracy requirements. The adjusted initial three-dimensional geological model is then determined as the target three-dimensional geological model for the corresponding monitoring cycle and monitoring period. S4. During the current monitoring period when the sensing fiber optic cables are first deployed at the tunnel face, based on the target 3D geological model obtained during the monitoring period before the continued excavation at the tunnel face, the geological characteristics of the rock and soil in front of the tunnel face are obtained, and an advanced geological forecast report is issued. The advanced geological forecast report is updated in a timely manner based on the target 3D geological model obtained during the monitoring period after the continued excavation at the tunnel face. The stability of the rock and soil in front of the tunnel face is analyzed based on the target 3D geological model obtained in the current monitoring period, and the stability characteristic value of the rock and soil structure is calculated. When the stability characteristic value of the rock and soil structure in front of the tunnel face exceeds the warning threshold of the stability characteristic value of the rock and soil structure, an automatic alarm is triggered, and handling suggestions are proposed in light of engineering problem examples. S5. During tunnel construction, based on the site vibration information acquired during each monitoring period under each monitoring cycle, tunnel construction noise and vibration data are extracted to obtain the daily construction time, frequency, and progress. The monitored construction time, frequency, and progress are compared with the construction plan and current specifications to assess the compliance of the construction. Based on the target three-dimensional geological model acquired during each monitoring period under each monitoring cycle, the stability of the rock and soil mass around the tunnel wall and in front of the tunnel face is analyzed. The stability characteristic value of the rock and soil mass structure and the difference between the stability characteristic values ​​of the rock and soil mass structure are calculated. When the stability characteristic value of the rock and soil mass structure exceeds the stability characteristic value of the rock and soil mass structure, an early warning is issued. The system automatically alarms when the difference in the characteristic values ​​of the stability of the soil and rock structure exceeds the warning threshold, and provides handling suggestions based on engineering problem examples. Based on the deformation and strain data of the soil and rock mass acquired during each monitoring period under each monitoring cycle, the system obtains the deformation status of the soil and rock mass surrounding the tunnel wall, calculates the characteristic values ​​of soil and rock deformation and strain, and the difference between these characteristic values. It automatically alarms when the characteristic value of soil and rock deformation and strain exceeds the warning threshold, or when the difference between these characteristic values ​​exceeds the warning threshold, and provides handling suggestions based on engineering problem examples. S6. During tunnel operation, the stability of the surrounding rock and soil is analyzed based on the target three-dimensional geological model obtained during each monitoring period under each monitoring cycle. The stability characteristic value and the difference between the stability characteristic values ​​of the rock and soil are calculated. An automatic alarm is triggered when the stability characteristic value of the rock and soil exceeds the warning threshold, or when the difference between the stability characteristic values ​​of the rock and soil exceeds the warning threshold for the difference between the stability characteristic values ​​of the rock and soil. Treatment suggestions are also provided based on engineering problem examples. Furthermore, the deformation of the surrounding rock and soil is obtained based on the deformation and strain data of the rock and soil obtained during each monitoring period under each monitoring cycle. The deformation and strain characteristic value and the difference between the deformation and strain characteristic values ​​of the rock and soil are calculated. An automatic alarm is triggered when the deformation and strain characteristic value of the rock and soil exceeds the warning threshold, or when the difference between the deformation and strain characteristic values ​​of the rock and soil exceeds the warning threshold for the difference between the deformation and strain characteristic values ​​of the rock and soil. Treatment suggestions are also provided based on engineering problem examples. The principle for arranging the sensing optical fibers in step S1 is as follows: the sensing optical fibers on the tunnel sidewalls, bottom plate and top plate are laid continuously, while the sensing optical fibers on the tunnel face are laid intermittently. The specific steps of deploying sensing optical fibers in the excavated section of the tunnel in step S1 include: excavating small trenches in the excavated section of the tunnel, burying the sensing optical fibers inside the trenches, and backfilling and fixing them with soil or construction grout; the sensing optical fibers deployed in the tunnel sidewalls, bottom slabs, and top slabs are connected to an optical fiber demodulator at one end at the tunnel excavation inlet, and a free section is left at the end near the tunnel excavation face. As the tunnel is continuously excavated, the free section of the optical fiber is continuously deployed along the newly excavated section in the tunnel; the sensing optical fibers deployed in the tunnel face are connected to an optical fiber demodulator at one end, and are directly removed after monitoring as the tunnel is excavated. As the tunnel is excavated, the sensing optical fibers are re-deployed in the new tunnel face to be monitored. In step S2, the deformation strain of the soil and rock mass is the strain generated by the internal deformation of the soil and rock mass, the site vibration strain is the strain generated by the soil and rock mass sensing the site vibration signal, the deformation strain rate of the soil and rock mass is the strain rate generated by the internal deformation of the soil and rock mass, and the site vibration strain rate is the strain rate generated by the soil and rock mass sensing the site vibration signal; the sources that excite the site vibration signal include construction noise, environmental noise and man-made earthquakes, and man-made earthquakes include various types such as hammering and gunpowder explosion; The geological characteristics of the soil and rock mass mentioned in step S3 include lithological distribution, porosity, development of fissures and karst caves, and groundwater distribution. After tunnel excavation, the actual geological characteristics of the newly excavated section are added to the initial three-dimensional geological model of the latest monitoring period in the current monitoring cycle. The resulting new three-dimensional geological model is set as the initial three-dimensional geological model for the next adjacent monitoring cycle and monitoring period. In the current monitoring cycle, the actual geological characteristics of the newly excavated section of the tunnel are compared with the geological characteristics reflected by the derived target three-dimensional geological model. The differences between the two are analyzed, the errors of the target three-dimensional geological model are identified, and the parameters of the iterative optimization algorithm are improved. In the next monitoring cycle, the improved iterative optimization algorithm is used to adjust the initial three-dimensional geological model. Step S5, which involves extracting tunnel construction noise and vibration data based on site vibration information acquired during each monitoring period under each monitoring cycle, to obtain the daily construction time, frequency, and progress, specifically includes: analyzing the extracted tunnel construction noise and vibration data; obtaining the start and end times and working periods of daily construction based on the time characteristics of noise vibration; obtaining the working frequencies of different construction equipment and procedures based on the frequency distribution of noise vibration and the noise frequency characteristics generated by different types of construction equipment; and determining the progress of construction based on the intensity, frequency changes, and vibration location of noise vibration. In steps S4, S5, and S6, the stability characteristic values ​​of the rock and soil mass include at least the length of crack development, the size of karst cave development, the width of fault development, the groundwater level, the range of weak rock strata development, and the range of unstable areas. In steps S5 and S6, the deformation and strain characteristic values ​​of the rock and soil mass include at least daily strain, monthly strain, and cumulative strain. The difference in the stability characteristic values ​​of the rock and soil mass is the maximum difference between the stability characteristic values ​​of the rock and soil mass in the latest monitoring period under the current monitoring cycle and the stability characteristic values ​​of the rock and soil mass in the monitoring period under other previous monitoring cycles. The difference in the deformation and strain characteristic values ​​of the rock and soil mass is the maximum difference between the deformation and strain characteristic values ​​of the rock and soil mass in the latest monitoring period under the current monitoring cycle and the deformation and strain characteristic values ​​of the rock and soil mass in the monitoring period under other previous monitoring cycles. For the rock and soil mass located at different locations in the tunnel, different warning thresholds for the stability characteristic values ​​of the rock and soil mass, the difference in the stability characteristic values ​​of the rock and soil mass, the deformation and strain characteristic values ​​of the rock and soil mass, and the difference in the deformation and strain characteristic values ​​of the rock and soil mass are preset according to current specifications and construction requirements. Throughout the entire construction and use period of the tunnel, historical and real-time data are analyzed regularly. The structural stability and deformation strain characteristics of the surrounding rock and soil of the tunnel wall are compared with those of each monitoring period under each monitoring cycle. The time periods with obvious abnormal values ​​and trends are identified. The construction and natural factors that cause abnormal values ​​and trends are analyzed, and monitoring reports are generated to improve and prevent the tunnel in subsequent construction and use. The device includes a sensing fiber, a fiber optic demodulator, and a central processing station. The fiber optic demodulator is used to emit laser pulses into the sensing fiber and receive Brillouin scattered light, Rayleigh scattered light, and Raman scattered light propagating backward from the sensing fiber. The demodulated optical signal obtains the frequency shift of the Brillouin scattered light, the phase change of the Rayleigh scattered light, and the intensity of the Raman scattered light, thus obtaining strain information and strain rate information at various points along the sensing fiber's arrangement. The central processing station includes: The data receiving and processing module is used to divide the monitoring cycle and monitoring period, acquire the strain information and strain rate information of the rock and soil mass measured by the fiber optic integrated demodulator, distinguish the strain information into the deformation strain of the rock and soil mass and the site vibration strain, distinguish the strain rate information into the deformation strain rate of the rock and soil mass and the site vibration strain rate, extract the site vibration information from the site vibration strain rate, obtain the measured surface wave dispersion curve, and deduce the target three-dimensional geological model for each monitoring period under each monitoring cycle. The tunnel advanced geological prediction module is used to obtain the geological characteristics of the rock and soil in front of the tunnel face based on the target three-dimensional geological model obtained in the current monitoring cycle, and generate an advanced geological prediction report. The tunnel construction safety monitoring module is used to extract tunnel construction noise vibration data based on site vibration information obtained during tunnel construction, to obtain daily construction time, frequency and progress, in order to assess the standardization of tunnel construction; and to analyze the stability of the rock and soil around the tunnel wall and in front of the tunnel face based on the target three-dimensional geological model obtained from the site; and to obtain the deformation of the rock and soil around the tunnel wall based on the deformation strain of the rock and soil obtained from the site. The tunnel construction safety monitoring module is used to analyze the stability of the rock and soil around the tunnel wall based on the target three-dimensional geological model obtained from the site during the tunnel's use; and to obtain the deformation of the rock and soil around the tunnel wall based on the deformation strain of the rock and soil obtained from the site. The tunnel safety early warning module is used to automatically alarm during tunnel construction and use based on the monitoring results of the tunnel advanced geological prediction module, tunnel construction safety monitoring module, and tunnel post-construction safety monitoring module. When the stability characteristic value of the rock and soil mass exceeds the early warning threshold, or when the difference between the stability characteristic values ​​of the rock and soil mass exceeds the early warning threshold, or when the difference between the deformation and strain characteristic values ​​of the rock and soil mass exceeds the early warning threshold, the module analyzes the engineering geological problems of the tunnel rock and soil mass corresponding to the monitoring cycle and monitoring period of the automatic alarm and generates a report on engineering problem handling suggestions. The tunnel safety early warning module has a built-in engineering problem instance database. This database covers problems encountered during tunnel construction and use, along with corresponding handling methods. For automatically alarmed tunnel geotechnical problems, the module retrieves similar engineering instances from the database by analogy with the site's main geological conditions, tunnel excavation depth and burial conditions, and engineering geological problem types. Based on the handling methods and strategies in the most similar engineering instances, the module generates an engineering problem handling suggestion report. It also records in detail the engineering problems, handling methods, and handling effects of the monitored tunnels, and inputs these new records into the engineering problem instance database to continuously update and expand its capacity.

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