Rail transit tunnel settlement monitoring method and system

Abstract

The invention provides a rail transit tunnel settlement monitoring method and system, and the method comprises the following steps: arranging displacement sensors at a vault, a haunch, a side wall and a bottom plate at preset intervals in a rail transit tunnel according to the structure and geological conditions of the tunnel; collecting measurement data of the displacement sensor at a preset time interval; the collected measurement data are preprocessed, a three-dimensional finite element model of the tunnel is established, inversion analysis is conducted in combination with the preprocessed measurement data, and meanwhile the settlement amount is calculated in combination with a settlement model; when the settlement value exceeds a preset settlement safety threshold value, an alarm device is triggered to give an alarm, and a settlement report is generated. Safety accidents caused by settlement can be effectively avoided, and normal operation and the service life of a rail transit system are guaranteed.

Description

Technical Field

[0001] The present invention belongs to the field of rail transit, and in particular relates to a method and system for monitoring the settlement of a rail transit tunnel. Background Art

[0002] With the rapid development of rail transit, tunnels, as an important part of it, will be affected by many factors during long-term operation, such as geological conditions, train vibration, groundwater changes, surrounding construction, etc., which may cause tunnel settlement. Tunnel settlement will affect the smoothness of the track and the safe operation of the train, and may even cause serious safety accidents. At present, the existing tunnel settlement monitoring methods have some limitations, such as low monitoring accuracy, limited monitoring range, low data collection and processing efficiency, and inability to monitor continuously in real time. Therefore, a more accurate, efficient, real-time and comprehensive rail transit tunnel settlement monitoring method and system is needed to ensure the safe operation of rail transit. Summary of the invention

[0003] The purpose of the present invention is to provide a method and system for monitoring the settlement of a rail transit tunnel, so as to overcome the problems of low monitoring accuracy, limited range, and inability to continuously monitor in real time in the prior art, and to achieve accurate, efficient, real-time and comprehensive monitoring of the settlement of a rail transit tunnel, thereby ensuring the safe operation of rail transit.

[0004] The technical solution of the present invention is as follows: A method for monitoring settlement of a rail transit tunnel comprises the following steps: In rail transit tunnels, displacement sensors are arranged at predetermined intervals on the arch, haunch, side wall and floor according to the structure and geological conditions of the tunnel; collecting measurement data of the displacement sensor at predetermined time intervals; Preprocess the collected measurement data. Establish a three-dimensional finite element model of the tunnel, perform inversion analysis based on the preprocessed measurement data, and calculate the settlement based on the settlement model; When the settlement value exceeds the preset settlement safety threshold, the alarm device is triggered to sound an alarm and generate a settlement report.

[0005] Furthermore, the preprocessing includes: Remove noise through adaptive filtering algorithm; By calculating the mean and standard deviation, outliers that exceed the mean are eliminated.

[0006] Furthermore, the three-dimensional finite element model of the tunnel is established and the inversion analysis is performed in combination with the pre-processed data as follows: According to the tunnel design, construction data and geological survey report, a three-dimensional finite element model is constructed through ABAQUS or ANSYS software to divide the tunnel structure and rock and soil units.

[0007] Assigning material properties to the tunnel structure and rock and soil units; Set boundary conditions based on burial depth and geology; The preprocessed data is input into the three-dimensional finite element model, and the actual parameters of the rock mass and structure are determined using an optimization algorithm such as the least square method.

[0008] Furthermore, the prediction of the settlement trend by combining the settlement model is specifically as follows: According to the structural and rock and soil parameters obtained by inversion, the settlement is calculated according to the settlement model; the settlement model is specifically: , Where S is the final settlement, is the volume compressibility coefficient, is the vertical additional stress, H is the soil thickness.

[0009] Furthermore, the settlement safety threshold is determined according to the design specifications, structural requirements and operational safety requirements of the tunnel.

[0010] The present invention also provides a rail transit tunnel settlement monitoring system, comprising: The displacement sensor system is composed of displacement sensors arranged at predetermined intervals at the arch, arch waist, side wall and bottom plate in the rail transit tunnel; A data acquisition system is connected to the displacement sensor system and collects measurement data of the displacement sensor at predetermined time intervals; Data preprocessing system, preprocessing the collected data; Finite element analysis and inversion system, used to establish a three-dimensional finite element model of the tunnel, set boundary conditions and perform inversion analysis; The settlement prediction system calculates the settlement amount using the settlement model in combination with the parameters obtained by inversion; The alarm and report generation system triggers the alarm device when the settlement value exceeds the preset settlement safety threshold and generates a settlement report.

[0011] Furthermore, the displacement sensor includes a laser displacement sensor, a static level or a strain displacement sensor.

[0012] Furthermore, the alarm device of the alarm and report generating system includes an audible and visual alarm, a text message alarm and a remote monitoring platform alarm.

[0013] Compared with the prior art, the present invention has the following advantages: The present invention achieves comprehensive and targeted monitoring of key parts of the tunnel by arranging displacement sensors at predetermined intervals at the arch, haunch, side wall and bottom plate in the rail transit tunnel according to the structure and geological conditions, and can timely capture settlement information at different positions. Secondly, the measurement data of the displacement sensor is collected at predetermined time intervals, and the data is preprocessed. The noise is removed by using an adaptive filtering algorithm, and the outliers are eliminated by calculating the mean and standard deviation, which effectively ensures the quality of the data and provides a reliable data basis for subsequent analysis. Furthermore, a three-dimensional finite element model of the tunnel is established and inversion analysis is performed in combination with the preprocessed data, so that the mechanical state of the tunnel structure and rock and soil can be more accurately understood, and the actual parameters are determined by the optimization algorithm to ensure the accuracy of the model. At the same time, the settlement is calculated in combination with the settlement model, and the structural and rock and soil parameters obtained by inversion are comprehensively considered, so that the calculation of the settlement is more scientific and reasonable. Moreover, when the settlement value exceeds the settlement safety threshold determined according to the tunnel design specifications, structural requirements and operational safety requirements, the alarm device will be triggered to sound an alarm and generate a settlement report. The alarm device includes multiple methods such as sound and light alarms, SMS alarms and remote monitoring platform alarms, which can transmit settlement risk information to operation and maintenance personnel in a multi-channel and timely manner, providing sufficient information support for taking targeted maintenance and preventive measures, thereby greatly improving the safety of rail transit tunnels and the reliability of operations, effectively avoiding safety accidents caused by settlement, and ensuring the normal operation and service life of the rail transit system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the description and claims, serve to illustrate the embodiments of the invention. Where appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method.

[0015] Figure 1 A schematic diagram of the process of the present invention is shown. DETAILED DESCRIPTION

[0016] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0017] like Figure 1 As shown, the implementation of the rail transit tunnel settlement monitoring method of the present invention mainly includes the following steps: arrangement and installation of displacement sensors, data acquisition and preprocessing, establishment and inversion analysis of a three-dimensional finite element model, settlement calculation and prediction, and alarm and report generation, specifically: Arrangement and installation of displacement sensor: According to the tunnel structure and geological survey report, determine the key monitoring positions of the tunnel, including the arch, arch waist, side wall and floor, etc. For areas with stable geological conditions and simple structures, the displacement sensors are arranged at a spacing of 20 meters; for areas with complex geological conditions (such as soft soil layers, faults, karst caves, etc.) or special structural parts (such as tunnel bends, connecting sections, etc.), the spacing of the displacement sensors is reduced to 5-10 meters.

[0018] Select laser displacement sensors, static levels or strain gauge displacement sensors for layout. During installation, ensure that the sensor is installed accurately, so that its measurement direction is consistent with the settlement direction of the tunnel structure, and is firmly fixed to the tunnel structure to avoid displacement or loosening of the sensor due to vibration or other external factors. For example, for laser displacement sensors, ensure that the relative position of the transmitter and receiver is stable and not affected by environmental factors such as water vapor and dust in the tunnel; for static levels, ensure that there is no leakage in the connecting pipe and that it is installed horizontally to ensure the accuracy of liquid level measurement.

[0019] Data collection and preprocessing: The data acquisition system is used with a data acquisition card or microcontroller as the core, connected to the displacement sensor, and a data acquisition channel is established. During normal operation, the data acquisition interval is set to once every 2 hours; when the tunnel is under construction or there are other construction activities in the surrounding area, the collection interval is shortened to once every 30 minutes. The collected data includes the measurement value of the displacement sensor and the precise timestamp, which is stored in the local storage device or cloud database.

[0020] The least mean square algorithm is used to remove noise, calculate the mean and standard deviation of the collected data, and remove data points that are out of range for the displacement data stored over a period of time.

[0021] Establishment and inverse analysis of three-dimensional finite element model: Create a 3D finite element model: According to the tunnel design drawings, construction data and geological survey reports, a three-dimensional finite element model was established using ABAQUS software. The tunnel lining structure was divided into shell elements, and the element size was adjusted according to the curvature and structural complexity of the tunnel, generally around 0.5-1 meters; the rock and soil body was divided into tetrahedral solid elements, and the element size was around 1-2 meters.

[0022] For tunnel lining, material properties are assigned to its units according to the designed concrete strength grade. For example, for C30 concrete, the elastic modulus is 30GPa, the Poisson's ratio is 0.2, and the density is 2500kg / m³; for rock and soil, different material properties are assigned to different soil layers according to the geological survey report.

[0023] Fixed constraints are applied to the bottom boundary of the model to limit the vertical displacement of the nodes; corresponding horizontal constraints are applied to the side boundaries based on the ground stress measurement data; considering the weight of the surface buildings and traffic loads, equivalent surface loads or displacement boundary conditions are applied to the surface boundaries. For example, for surface buildings, according to their weight and distribution area, an equivalent uniformly distributed load is calculated and applied to the corresponding surface units.

[0024] The preprocessed displacement data are input into the established three-dimensional finite element model, and the least square method is used as the optimization algorithm to finally obtain the structural and geotechnical parameters that are more in line with the actual situation.

[0025] According to the structural and geotechnical parameters obtained by inversion, the settlement model is used Calculate the amount of settlement.

[0026] The settlement model is derived based on the one-dimensional compression theory in soil mechanics: According to the soil compression test, under the condition of lateral confinement, the porosity ratio of the soil is e Vertical compressive stress There is a linear relationship between them, expressed as: , in, is the compression factor, in , represents the change in porosity caused by a change in unit vertical compressive stress. The negative sign indicates that the porosity decreases with increasing pressure. The change of void ratio, is the change in vertical compressive stress.

[0027] Volume compression factor It is defined as the volume change per unit volume of soil caused by a change in unit vertical compressive stress, and is related to the compression coefficient The relationship is: , in, is the initial void ratio of the soil.

[0028] Will Substituting it into the volume compression coefficient formula, we get: , in, The change of void ratio, is the change in vertical compressive stress, is the initial void ratio of the soil.

[0029] According to the definition of soil compressibility, the compression deformation (i.e. settlement) S of the soil layer is related to the change in porosity and initial soil thickness HThe expression is: , When the vertical additional stress increases from 0 to When , the porosity ratio changes to .

[0030] Will Transformed into ,here, , put it into the settlement formula and get: , The negative sign is eliminated during the substitution process. This is because in practical applications, we focus on the absolute value of the settlement, that is, the magnitude of the soil compression deformation, and do not care about the corresponding relationship between the direction of the change in the void ratio (increase or decrease) and the direction of the stress change (only from the perspective of numerical calculation).

[0031] Volume compression factor Determined by indoor compression test, for example, testing the soil sample at the bottom of the tunnel and calculating the volume compression coefficient based on the test data; vertical additional stress Including the stress caused by the soil's own weight and external load; for the soil's own weight, according to the formula Calculation, assuming that the thickness of the soil covering the tunnel bottom is h = 10m, m is meter, and the weight of the soil is , N is the unit of force, Newton, then the vertical additional stress caused by the soil's own weight is ; For external loads, the additional stress generated at the bottom of the tunnel is calculated according to the Boussinaisk solution, and then superimposed with the stress generated by the soil's own weight; soil layer thickness H According to the geological survey report, these parameters are substituted into the settlement model to calculate the final settlement.

[0032] Alarm and report generation: Settlement threshold setting: According to the design specifications and operational safety requirements of the tunnel, the settlement safety threshold is set at 30mm for the arch of the subway tunnel and 20mm for the arch of the high-speed railway tunnel. For different structural parts (such as side walls, bottom plates, etc.), corresponding thresholds are set according to the structural bearing capacity and safety requirements.

[0033] When the calculated settlement exceeds the settlement safety threshold, the alarm device is triggered. The alarm device includes an audible and visual alarm, a text message alarm, and a remote monitoring platform alarm. For example, a PLC is used to control the audible and visual alarm. When the settlement exceeds the threshold, the PLC sends a trigger signal to the audible and visual alarm, causing it to sound an audible and visual alarm. Through the SMS gateway, a text message notification containing settlement information is sent to relevant managers. At the same time, on the remote monitoring platform, the alarm information is notified to the operation and maintenance personnel in the form of a pop-up window, email, or message push.

[0034] Generate a settlement report, which includes: Basic information of settlement monitoring: including the monitored tunnel location, monitoring time range, sensor layout information, etc.

[0035] Sedimentation data and analysis results: including sedimentation amount, sedimentation rate (calculated by dividing the difference in sedimentation between adjacent time points by the time interval), and sedimentation trend analysis results (derived from physical and mechanical models and time series analysis results).

[0036] Structural and geotechnical parameters: List the actual parameters of the structure and geotechnical mass obtained through inversion analysis, as well as their impact on settlement.

[0037] Recommended measures: Based on the settlement situation, give corresponding maintenance suggestions, such as increasing the monitoring frequency, taking reinforcement measures or suspending operations.

[0038] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for monitoring settlement of a rail transit tunnel, characterized in that: The following steps are involved: In rail transit tunnels, displacement sensors are arranged at predetermined intervals on the arch, haunch, side wall and floor according to the structure and geological conditions of the tunnel; collecting measurement data of the displacement sensor at predetermined time intervals; Preprocess the collected measurement data. Establish a three-dimensional finite element model of the tunnel, perform inversion analysis based on the preprocessed measurement data, and calculate the settlement based on the settlement model; When the settlement value exceeds the preset settlement safety threshold, the alarm device is triggered to sound an alarm and generate a settlement report.

2. The method for monitoring settlement of a rail transit tunnel according to claim 1, characterized in that: The pre-processing comprises: Remove noise through adaptive filtering algorithm; By calculating the mean and standard deviation, outliers that exceed the mean are eliminated.

3. The method for monitoring settlement of a rail transit tunnel according to claim 1, characterized in that: The three-dimensional finite element model of the tunnel is established and the inversion analysis is performed in combination with the pre-processed data as follows: According to the tunnel design, construction data and geological survey report, a three-dimensional finite element model is constructed using ABAQUS or ANSYS software to divide the tunnel structure and rock and soil units; Assigning material properties to the tunnel structure and rock and soil units; Set boundary conditions based on burial depth and geology; The preprocessed data is input into the three-dimensional finite element model, and the actual parameters of the rock mass and structure are determined by the least square method.

4. The method for monitoring settlement of a rail transit tunnel according to claim 1, characterized in that: The prediction of the settlement trend by combining the settlement model is specifically as follows: According to the structural and rock and soil parameters obtained by inversion, the settlement is calculated according to the settlement model; the settlement model is specifically: ， Where S is the final settlement, is the volume compressibility coefficient, is the vertical additional stress, H is the soil thickness.

5. The method for monitoring settlement of a rail transit tunnel according to claim 1, characterized in that: The settlement safety threshold is determined according to the design specifications, structural requirements and operational safety requirements of the tunnel.

6. A rail transit tunnel settlement monitoring system applied to the rail transit tunnel settlement monitoring method according to any one of claims 1 to 5, characterized in that: include: The displacement sensor system is composed of displacement sensors arranged at predetermined intervals at the arch, arch waist, side wall and bottom plate in the rail transit tunnel; A data acquisition system is connected to the displacement sensor system and collects measurement data of the displacement sensor at predetermined time intervals; Data preprocessing system, preprocessing the collected data; Finite element analysis and inversion system, used to establish a three-dimensional finite element model of the tunnel, set boundary conditions and perform inversion analysis; The settlement prediction system calculates the settlement amount using the settlement model in combination with the parameters obtained by inversion; The alarm and report generation system triggers the alarm device when the settlement value exceeds the preset settlement safety threshold and generates a settlement report.

7. The rail transit tunnel settlement monitoring system according to claim 6, characterized in that: The displacement sensor includes a laser displacement sensor, a static level or a strain type displacement sensor.

8. The rail transit tunnel settlement monitoring system according to claim 6, characterized in that: The alarm device of the alarm and report generating system includes an audible and visual alarm, a text message alarm and a remote monitoring platform alarm.

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