A goaf high-speed railway subgrade settlement monitoring and early warning system and method

Abstract

The application provides a goaf high-speed railway subgrade settlement monitoring and early warning system and method, which combines GNSS settlement measurement technology, array displacement meter settlement measurement technology and distributed optical fiber settlement measurement technology to form integrated multi-directional monitoring on a goaf, avoids deep settlement and occurrence of a situation that the overall goaf cannot show settlement influence, and can reduce missed detection by using multiple measurement technologies.

Description

A monitoring and early warning system and method for subgrade settlement in high-speed railways in mining subsidence areas Technical Field

[0001] This invention belongs to the technical field of roadbed monitoring, and in particular relates to a monitoring and early warning system and method for roadbed settlement in mining subsidence areas of high-speed railways. Background Technology

[0002] A goaf is an area and extent of surface deformation and damage caused by the instability of the surrounding rock after underground mining, resulting in displacement, cracking, fracturing, and collapse, until the overlying strata subside and bend. As the area of ​​goafs continues to increase, more and more construction projects inevitably face the impact of goafs. There are increasingly more instances of utilizing abandoned goaf sites for construction. The gradual expansion of high-speed railway networks necessitates their passage through goafs, but goafs are prone to uneven settlement and deformation, posing a serious threat to high-speed railway safety and the lives and property of people. Therefore, accurate monitoring and prediction of goaf settlement and horizontal deformation are of great significance for railway safety.

[0003] Currently, there are many methods for settlement monitoring, such as manual leveling, settlement plate method, electromagnetic stratified settlement meter method, horizontal inclinometer method, and laser displacement measurement. Traditional settlement monitoring instruments are mostly point-based, which have drawbacks such as missed detections, large monitoring errors, low automation level, and large workload. At the same time, most existing monitoring methods are traditional manual monitoring, which is greatly affected by human factors, has insufficient monitoring frequency, cannot meet the requirements of high-precision monitoring, and has a lag. Due to the wide measurement range, large amount and complexity of data, and environmental factors such as weather, traditional monitoring methods cannot meet the requirements of real-time and accurate monitoring. In terms of monitoring dimensions, current high-speed railway subgrade settlement analysis mainly focuses on the overall analysis of the subgrade, ignoring the analysis of deep settlement and failing to obtain the settlement situation of the deep structure inside the overburden. Summary of the Invention

[0004] To overcome the shortcomings of the existing technology, this invention provides a monitoring and early warning system and method for subgrade settlement in high-speed railways in goaf areas. By combining GNSS settlement measurement technology, array displacement meter settlement measurement technology, and distributed optical fiber settlement measurement technology, the system monitors the goaf area from two dimensions: the surface and the deep overburden layer. This avoids situations where deep subsidence occurs but the overall goaf area does not show any settlement impact.

[0005] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solution: a high-speed railway subgrade settlement monitoring and early warning system for mining subsidence areas, comprising:

[0006] Monitoring and early warning terminals, as well as GNSS settlement acquisition devices, array displacement meter acquisition devices, and distributed optical fiber acquisition devices that communicate with the monitoring and early warning terminals;

[0007] The GNSS settlement acquisition device includes a GNSS transmitter set outside the surface movement edge of the goaf and a GNSS receiver set at the monitoring point in the goaf to monitor and measure the settlement at the monitoring point in the goaf area.

[0008] The array-type displacement meter acquisition device includes displacement meters laid along key unstable sections of the high-speed railway subgrade to monitor and measure surface subsidence in the goaf area.

[0009] The distributed optical fiber acquisition device includes distributed optical fibers installed at key instability points of the high-speed railway subgrade to monitor and measure deep subsidence inside the overburden of the goaf.

[0010] The monitoring and early warning terminal receives and processes monitoring and measurement data from the GNSS settlement acquisition device, array displacement gauge, and distributed optical fiber acquisition device to achieve multi-dimensional settlement monitoring and early warning of the goaf area.

[0011] A second aspect of the present invention is a method for monitoring and early warning of subgrade settlement in high-speed railways in mining subsidence areas, comprising:

[0012] Acquire various types of settlement monitoring data, including data collected by GNSS settlement acquisition devices at monitoring points in the goaf area, data collected by array displacement gauge acquisition devices at key unstable sections of the high-speed railway subgrade, and data collected by distributed optical fiber acquisition devices at key unstable points of the high-speed railway subgrade.

[0013] Settlement values ​​were calculated using a sedimentation calculation model for the various types of collected data.

[0014] The obtained settlement value is compared with the preset settlement threshold to conduct monitoring and early warning.

[0015] The above one or more technical solutions have the following beneficial effects:

[0016] This invention combines GNSS settlement measurement technology, array-type displacement gauge settlement measurement technology, and distributed fiber optic settlement measurement technology to achieve integrated, multi-directional monitoring of the goaf area. This avoids situations where deep-seated settlement occurs without the overall goaf area showing any settlement impact. The use of multiple measurement technologies reduces missed detections and effectively provides safety assurance for trains traveling in various complex natural environments, demonstrating broad applicability.

[0017] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 is a schematic diagram of the framework of a high-speed railway subgrade settlement monitoring and early warning system in a mining subsidence area according to Embodiment 1 of the present invention;

[0020] Figure 2 is a schematic diagram of the monitoring point arrangement in Embodiment 1 of the present invention.

[0021] In the diagram, 1 is the leveling instrument measuring point, 2 is the track, 3 is the critical instability section, and 4 is the critical instability point. Detailed Implementation

[0022] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0024] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0025] Example 1

[0026] As shown in Figure 1, this embodiment discloses a high-speed railway subgrade settlement monitoring and early warning system in a mining subsidence area, comprising:

[0027] Monitoring and early warning terminals, as well as GNSS settlement acquisition devices, array displacement meter acquisition devices, and distributed optical fiber acquisition devices that communicate with the monitoring and early warning terminals;

[0028] The GNSS settlement acquisition device includes a GNSS transmitter set outside the surface movement edge of the goaf and a GNSS receiver set at the monitoring point in the goaf to monitor and measure the settlement at the monitoring point in the goaf area.

[0029] The array-type displacement meter acquisition device includes displacement meters laid along key unstable sections of the high-speed railway subgrade to monitor and measure surface subsidence in the goaf area;

[0030] The distributed optical fiber acquisition device includes distributed optical fibers installed at key instability points of the high-speed railway subgrade to monitor and measure deep subsidence inside the overburden of the goaf.

[0031] The monitoring and early warning terminal receives and processes monitoring and measurement data from the GNSS settlement acquisition device, array displacement gauge, and distributed optical fiber acquisition device to achieve multi-dimensional settlement monitoring and early warning of the goaf area.

[0032] In this embodiment, the GNSS settlement acquisition device mainly measures the settlement of multiple monitoring points in the goaf area, including multiple monitoring stations and one reference point. A monitoring station refers to a GNSS signal receiver, and the reference station refers to a GNSS signal transmitter. The GNSS receiver is communicatively connected to a monitoring terminal. The monitoring terminal processes the signal using GNSS processing software, which incorporates an RTK high-frequency algorithm. The data is then displayed through a visualization platform. The RTK algorithm obtains the ground coordinates based on the received known satellite position information using the four-sphere positioning principle. The RTK differential positioning method compares the known coordinates of the reference station with the measured coordinates to obtain a common error value within a certain range of the measurement area centered on the reference station. The built-in RTK algorithm can eliminate the common error value at the measurement point, obtaining the precise coordinates of the measurement point. The settlement value is displayed by comparing the magnitude of these real-time coordinates before and after the change.

[0033] Before carrying out engineering construction in a goaf area, an engineering survey should be conducted in advance to ascertain the engineering geological conditions such as the underlying lithology of the overlying rock strata and foundation soil, regional geological structure, mining history, current mining status, mining scope and depth, distribution of goaf tunnels, cross-sectional dimensions and corresponding surface locations, and overlying rock and collapse types, development patterns, lithological combinations and their stability.

[0034] By analyzing data from the goaf exploration, the mining dip angle is determined, thereby identifying the surface movement edge. A benchmark station is then set outside this edge, where deformation is minimal and stability is high. Monitoring points are established at the goaf settlement monitoring points. Using the coordinates of the benchmark station, the distance to the satellite is tracked and measured. The satellite coordinates are then calculated. Based on these coordinates, the distance from the receiver to the satellite is measured. The receiver's position is calculated using a three-sphere or four-sphere positioning method. Settlement measurements are then taken at the monitoring points based on changes in relative coordinates.

[0035] This embodiment uses the setting of 3 monitoring stations as an example for explanation. Two monitoring stations are set at two points near the intersection of the railway line and the perimeter of the goaf, without affecting the railway operation. One monitoring station is set at the center point of the settlement funnel near the goaf.

[0036] In this embodiment, the array-type displacement gauge acquisition device includes multiple measuring units of equal length. Each measuring unit is a high-strength waterproof sealed tube made of 304 stainless steel, with a displacement gauge built into it. The displacement gauge measures vertical displacement and includes a built-in temperature measuring unit for automatic temperature compensation. The displacement gauges are laid laterally on the ground surface, perpendicular to the train's direction of travel, to monitor vertical settlement and horizontal displacement. The displacement gauges are laterally arranged at key instability sections along the railway line. The array-type displacement gauge is a linear displacement measuring device that places the displacement gauge inside a stainless steel tube. It is arranged at key instability sections, laid laterally perpendicular to the train's direction of travel. The array-type displacement gauge can simultaneously measure horizontal and vertical displacement. The data output from this array-type displacement gauge is the vertical and horizontal displacement. Each measuring unit node integrates a high-performance processor to quickly process the acquired data, perform real-time calculations, and directly output the calculation results.

[0037] Multiple measurement units are internally connected through a bus structure. Each measurement unit independently acquires and processes loudness data. The acquired data is aggregated to the control unit via the bus. This control unit communicates with the outside world through a cable interface, using a standard RS485 interface (default) or RS232 interface for output. It can be directly connected to a DTU, serial server, or other data acquisition device without the need for dedicated data acquisition equipment.

[0038] The DTU (Digital Terminal Unit) data transmission method converts serial port data into IP data, which is then transmitted via a wireless communication network. Each measuring unit of the array displacement gauge integrates a high-performance processor for rapid data processing and real-time calculations, directly outputting the results. This significantly reduces the amount of data transmitted over long distances and the computational load on the platform. During long-term monitoring, damage to individual measuring points will not affect data continuity or impact other nodes.

[0039] As shown in Figure 2, the critical instability section is the plane perpendicular to the railway track line where the critical instability point is located. The critical instability point is determined based on the remaining subsidence value ΔW and the remaining horizontal deformation value Δε. If either ΔW ≥ 100 mm or Δε ≥ 2 mm / m is satisfied, the point is determined to be the critical instability point.

[0040] Taking a coal seam dip angle α of less than 15° as an example, the formula for calculating the expected surface subsidence of the goaf based on the probability integral method is as follows:

[0041]

[0042] Where x and y are the relative coordinates of the calculation point; W cm For maximum subsidence, under fully mined conditions, Wcm =M·q·cosα, where M is the normal thickness of the mined ore seam, q represents the subsidence coefficient, α is the dip angle of the coal seam, r is the main influence radius, D is the mining area of ​​the coal seam, and η and ζ are calculation coefficients.

[0043] The formula for calculating the predicted horizontal deformation of the goaf based on the probability integral method is as follows:

[0044]

[0045]

[0046] Among them, U cm The maximum horizontal movement value is U, representing the maximum horizontal movement along the strike of the coal seam. cm =b·W cm b is the horizontal movement coefficient, determined based on the lithology of the overlying strata; θ0 is the angle of propagation of mining influence, determined based on the lithology of the overlying strata.

[0047] The remaining displacement deformations ΔW and Δε are determined by subtracting the already occurred displacement deformation value from the expected value of surface displacement deformation under mining conditions. The already occurred displacement deformation value is determined based on the difference between the current topography and the original topography, according to the survey data.

[0048] In this embodiment, the distributed optical fiber acquisition device includes distributed optical fiber sensors arranged at the boreholes. Boreholes are set at key instability points, and the distributed optical fiber sensors detect deep settlement within the overburden. Boreholes are drilled at the key instability points, and the distributed optical fiber sensors are inserted along the holes. The system is then connected to the monitoring host for on-site debugging. After debugging, the soil is backfilled and compacted. One end of the optical fiber is tied to an L-shaped bracket, and the other end is inserted into the soil surface for positioning. After the distributed optical fiber sensors are connected to the acquisition device, they can display the corresponding data along the optical fiber line (i.e., under the overburden). This is the function of the sensor acquisition device.

[0049] After the distributed fiber optic sensors are deployed, they are connected to the automated data acquisition instrument. By setting the data acquisition frequency, the automated data acquisition instrument connects to the wireless terminal device through the connection interface, and then the wireless terminal device transmits data to the monitoring and early warning terminal through the wireless communication network.

[0050] In this embodiment, a tilting machine is also deployed while drilling holes at the critical instability point to arrange distributed fiber optic sensors, in order to measure the tilt angle of the critical instability point and determine whether horizontal displacement has occurred.

[0051] In this embodiment, leveling instruments are installed every 10m along the railway line and at key instability points within the goaf area to monitor surface subsidence.

[0052] In this embodiment, the monitoring and early warning terminal has a preset settlement threshold judgment algorithm to determine whether the collected settlement data exceeds a preset threshold. If it exceeds the threshold, the alarm system is controlled to issue a tiered alarm; otherwise, the data is stored in the database. At the critical instability points, both array-type displacement gauges and levels were used to measure settlement, with the level data being the most accurate. Each measurement technique can produce a curve showing the relationship between displacement and time at the corresponding point, and each displacement is judged individually based on a threshold.

[0053] During the construction and operation phases of high-speed railways, the settlement monitoring environment often includes noise from train vibrations and construction interference. Therefore, it is necessary to filter the collected data to ensure its accuracy. The real-time data collected on-site is filtered and denoised using an adaptive filtering algorithm based on Kalman filtering, with the algorithm having a built-in acquisition unit.

[0054] According to the provisions of my country's "Design Code for High-Speed ​​Railways" TB 10621-2014, it is recommended to set settlement thresholds of 2mm, 15mm, and 30mm, which can be adjusted according to the actual situation of the project. When the settlement is less than 2mm, it indicates that the roadbed is gradually settling from a stable state, indicating a change in roadbed stability, reminding the railway operation department to strengthen the monitoring of roadbed settlement; when the settlement is greater than or equal to 2mm but less than 15mm, it indicates that the settlement is already relatively large, and the railway operation department should refer to the system's suggestions to prepare possible contingency plans; when the settlement is greater than or equal to 15mm but less than 30mm, it indicates that the roadbed settlement is already quite serious, reminding the railway operation department to take timely action, referring to the system's suggestions to adjust the rail surface elevation to the design elevation, and if adjustment is not possible, railway operation should be stopped immediately; when the settlement is greater than or equal to 30mm, it indicates that the settlement is very serious, and there may be a risk of derailment, requiring immediate cessation of railway operation.

[0055] Furthermore, real-time data collected on-site is stored in a cloud storage big data center via LAN, WLAN, and 5G. A visualization system allows for the retrieval of historical settlement data maps from the project site at any time. Simultaneously, based on on-site data and the analysis of high-speed railway settlement big data using machine learning and deep learning technologies, a built-in grey prediction algorithm in the intelligent cloud platform can predict future settlement data based on past settlement data, generating a future settlement trend curve. Based on the distribution of mine tunnels and geological conditions in the goaf areas, the causes of settlement at alarm locations can be analyzed. Through IoT technology, nearby cameras are accessed to display the real-time situation, and the coordinates of the alarm location and the situation are notified to relevant personnel via SMS. Based on maintenance and reinforcement suggestions provided by the intelligent cloud platform, measures are taken at the alarm location.

[0056] It can also include mobile terminals, allowing on-site inspection personnel to submit on-site inspection results and upload on-site location information and image information to the cloud storage big data center in real time.

[0057] Example 2

[0058] The purpose of this embodiment is to provide a method for monitoring and early warning of subgrade settlement in high-speed railways in mining subsidence areas, including:

[0059] Acquire various types of settlement monitoring data, including data collected by GNSS settlement acquisition devices at monitoring points in the goaf area, data collected by array displacement gauge acquisition devices at key unstable sections of the high-speed railway subgrade, and data collected by distributed optical fiber acquisition devices at key unstable points of the high-speed railway subgrade.

[0060] Settlement values ​​were calculated from the various types of collected data.

[0061] The obtained settlement value is compared with the preset settlement threshold to conduct monitoring and early warning.

[0062] Example 3

[0063] The purpose of this embodiment is to provide a computing device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the above-described method.

[0064] Example 4

[0065] The purpose of this embodiment is to provide a computer-readable storage medium.

[0066] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the steps of the above method.

[0067] The steps and methods involved in the apparatuses of Embodiments 2, 3, and 4 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.

[0068] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0069] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A monitoring and early warning system for subgrade settlement in high-speed railways in mining subsidence areas, characterized in that, include: Monitoring and early warning terminals, as well as GNSS settlement acquisition devices, array displacement meter acquisition devices, and distributed optical fiber acquisition devices that communicate with the monitoring and early warning terminals; The GNSS settlement acquisition device includes a GNSS transmitter positioned outside the surface movement edge of the goaf and a GNSS receiver positioned at monitoring points in the goaf to monitor and measure settlement at these monitoring points. The array-type displacement gauge acquisition device includes displacement gauges laid along key unstable sections of the high-speed railway subgrade to monitor and measure surface settlement in the goaf. Each array-type displacement gauge includes multiple measurement units, each including a pipe and a displacement gauge installed within the pipe. The displacement gauges are laid laterally on the surface, perpendicular to the train's direction of travel, for vertical settlement and horizontal displacement monitoring. The distributed optical fiber acquisition device includes distributed optical fibers positioned at key unstable points in the high-speed railway subgrade to monitor and measure deep settlement within the overlying rock of the goaf. The remaining surface subsidence and remaining horizontal deformation values ​​are determined using a probability integral method. Key unstable points are identified based on whether the remaining subsidence or remaining horizontal deformation values ​​exceed preset thresholds. The monitoring and early warning terminal receives and processes the monitoring and measurement data from the GNSS settlement acquisition device, the array-type displacement gauges, and the distributed optical fiber acquisition device to achieve multi-dimensional settlement monitoring and early warning for the goaf.

2. The high-speed railway subgrade settlement monitoring and early warning system in a mining subsidence area as described in claim 1, characterized in that, It also includes an inclinometer, which is placed at the critical instability point of the high-speed railway subgrade to measure the inclination angle of the critical instability point.

3. The high-speed railway subgrade settlement monitoring and early warning system in a mining subsidence area as described in claim 1, characterized in that, It also includes a level instrument, which is set at key instability points of the high-speed railway subgrade and at intervals along the railway line to monitor surface subsidence.

4. The high-speed railway subgrade settlement monitoring and early warning system in a mining subsidence area as described in claim 1, characterized in that, The monitoring point is located at the intersection of the railway line and the perimeter of the goaf, or at the center of the settlement funnel in the goaf.

5. The high-speed railway subgrade settlement monitoring and early warning system in a mining subsidence area as described in claim 1, characterized in that, The monitoring and early warning terminal makes judgments based on the monitoring data received from the GNSS settlement acquisition device, the array displacement meter acquisition device, and the distributed optical fiber acquisition device, and issues graded early warnings and displays the geographical location corresponding to the early warning area.

6. A method for monitoring and early warning of subgrade settlement in high-speed railways in mining subsidence areas, characterized in that, include: This system acquires various types of settlement monitoring data, including data collected by a GNSS settlement acquisition device at monitoring points in the goaf area, data collected by an array-type displacement gauge acquisition device at key instability sections of the high-speed railway subgrade, and data collected by a distributed optical fiber acquisition device at key instability points of the high-speed railway subgrade. The array-type displacement gauge comprises multiple measurement units, each including a pipe and a displacement gauge installed within the pipe. The displacement gauge is laid laterally on the ground surface, perpendicular to the train's direction of travel, for vertical settlement monitoring and horizontal displacement monitoring. The key instability section is the surface perpendicular to the railway track line, and the key instability point is determined by the magnitude of the remaining surface subsidence and remaining horizontal deformation calculated using a probability integral method. Settlement values ​​are calculated from the acquired data of various types. The obtained settlement values ​​are compared with preset settlement thresholds for monitoring and early warning.

7. The method for monitoring and early warning of subgrade settlement in high-speed railways in mining subsidence areas as described in claim 6, characterized in that, The data collected by the GNSS settlement acquisition device is used to obtain corresponding settlement values ​​through adaptive algorithms and RTK high-frequency algorithms.

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