Roadbed differential settlement monitoring system with tracing and positioning functions

Abstract

The utility model belongs to the field of roadbed automatic monitoring, and discloses a roadbed differential settlement monitoring system with tracing and positioning functions, which comprises a plurality of distributed optical cables which are arranged in a roadbed in a criss-cross manner, and each distributed optical cable comprises a distributed strain sensing optical fiber and a GPS (Global Positioning System) transmission line; the plurality of GPS sensors are arranged at intersections of the criss-cross distributed optical cables, and each GPS sensor is connected with the GPS transmission line at the corresponding position; the optical fiber sensing demodulator is connected with the distributed strain sensing optical fiber; the GPS receiver is connected with the GPS transmission line; and the data storage device is connected with the optical fiber sensing demodulator and the GPS receiver. According to the utility model, the requirement of rapid and long-term large-range monitoring on the differential settlement of the roadbed can be met, and reliable technical support is provided for safe operation of roadbed engineering.

Description

Technical Field

[0001] The utility model belongs to the field of roadbed automatic monitoring, and in particular relates to a roadbed uneven settlement monitoring system with a tracing and positioning function. Background Art

[0002] As an important part of the road structure, the stability of the roadbed is directly related to the performance and driving safety of the road. However, in actual projects, the roadbed is often affected by various factors such as uneven filling, large differences in the thickness of the soft soil layer, and water erosion. Especially in the connection section between the rigid bridge and the flexible roadbed and the parts that are frequently subjected to traffic loads, the deformation of the roadbed will continue to accumulate, eventually leading to the occurrence of uneven settlement. This uneven settlement not only has a great adverse impact on construction and transportation, but may also cause a series of road diseases, seriously affecting the service life of the road and driving safety.

[0003] In order to effectively deal with the problem of uneven roadbed settlement, a variety of monitoring technologies have been traditionally used, such as the settlement plate method, the settlement meter method, and the monitoring pile method. These monitoring methods generally deploy monitoring sections at important locations and areas, and monitor the deformation of these section positions to ultimately determine the locations with large settlements and take corresponding prevention and control measures. However, these traditional monitoring technologies have many limitations, such as the inability to monitor for a long time, the inability to achieve continuous monitoring, and low monitoring efficiency. These problems have greatly limited traditional monitoring technologies in practical applications, making it difficult to meet the needs of rapid, long-term, and large-scale monitoring of uneven roadbed settlement. Summary of the invention

[0004] In view of the problems existing in the prior art, the utility model provides a roadbed uneven settlement monitoring system with a traceability positioning function, which can meet the needs of rapid, long-term and large-scale monitoring of roadbed uneven settlement, and provide reliable technical support for the safe operation of roadbed projects.

[0005] In order to solve the above technical problems, the utility model is implemented through the following technical solutions:

[0006] A roadbed uneven settlement monitoring system with retrospective positioning function, comprising:

[0007] A plurality of distributed optical cables are crisscrossed and arranged in the roadbed, each of the distributed optical cables comprising a distributed strain sensing optical fiber and a GPS transmission line;

[0008] A plurality of GPS sensors are arranged at the intersection of the crisscrossing distributed optical cables, and each of the GPS sensors is connected to the GPS transmission line at a corresponding position;

[0009] An optical fiber sensing demodulator connected to the distributed strain sensing optical fiber;

[0010] A GPS receiver connected to the GPS transmission line;

[0011] A data storage device is connected to the optical fiber sensor demodulator and the GPS receiver.

[0012] Furthermore, the monitoring system also includes:

[0013] A power supply device is electrically connected to the optical fiber sensor demodulator and the GPS receiver.

[0014] Furthermore, the power supply device is a photovoltaic power supply device.

[0015] Furthermore, a first protective sand layer is laid below the distributed optical cable, a second protective sand layer is laid above the distributed optical cable, and the GPS sensor is located between the first protective sand layer and the second protective sand layer.

[0016] Furthermore, in the transverse direction of the roadbed, the distance between two adjacent distributed optical cables is 5m to 10m.

[0017] Furthermore, along the longitudinal direction of the roadbed, the distance between two adjacent distributed optical cables is 10m to 50m.

[0018] Furthermore, each of the distributed optical cables further comprises:

[0019] A coating layer covering the outer surface of the distributed strain sensing optical fiber and the outer surface of the GPS transmission line;

[0020] An inner sheath covering the outer surface of the coating layer;

[0021] An outer sheath covering the outer surface of the inner sheath;

[0022] The reinforcing steel wire is arranged in the outer sheath.

[0023] Furthermore, the data storage device uses wireless communication with the optical fiber sensor demodulator and the GPS receiver.

[0024] Compared with the prior art, the utility model has at least the following beneficial effects:

[0025] The utility model provides a roadbed uneven settlement monitoring system with a tracing and positioning function. When the roadbed settles, the distributed strain sensing optical fiber corresponding to the location where the settlement occurs can monitor the strain information. The strain information is demodulated by the optical fiber sensor demodulator and sent to the data storage device. At the same time, the position of the GPS sensor corresponding to the location where the settlement occurs will change. The GPS receiver receives the GPS positioning information of the GPS sensor through the GPS transmission line and sends it to the data storage device. Researchers use the strain data and GPS positioning information stored in the data storage device, and combine each distributed optical cable and the position of each GPS sensor in the roadbed to determine the location where the settlement occurs. The utility model uses GPS positioning technology to trace the settlement value of the roadbed along the distributed optical cable 24 hours a day, locate the settlement position of the roadbed along the roadbed in real time, and realize the tracing and positioning function of the roadbed uneven settlement monitoring system. Based on optical fiber sensing technology, distributed strain sensing optical fibers are laid along the transverse and longitudinal sections of the roadbed to realize the settlement monitoring along the transverse and longitudinal sections of the roadbed, and the transverse and longitudinal settlement changes of the roadbed are measured in real time. This system can not only be applied to the roadbed construction stage, but also provide comprehensive monitoring and data support for the road operation, maintenance and repair stages. The system is less affected by climate and will not be unable to be measured due to rain, snow and extreme weather. It can operate around the clock, effectively ensuring the monitoring frequency, saving time, reducing manpower and material input, and has high monitoring efficiency. In summary, the utility model can meet the needs of rapid, long-term and large-scale monitoring of uneven settlement of the roadbed, provide reliable technical support for the safe operation of roadbed projects, and thus help improve the driving quality and road capacity of the road surface. It can also significantly reduce the safety hazards of motor vehicle driving and improve driving comfort, which is of great significance for ensuring road traffic safety and extending the service life of roads.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the specific implementation modes of the present invention, the drawings required for use in the description of the specific implementation modes will be briefly introduced below. Obviously, the drawings described below are some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 This is a schematic diagram of the overall structure of a roadbed uneven settlement monitoring system with a retrospective positioning function proposed by the utility model;

[0029] Figure 2This is a schematic diagram of the longitudinal section structure of a roadbed uneven settlement monitoring system with a retrospective positioning function proposed by the utility model;

[0030] Figure 3 This is a schematic diagram of the cross-sectional structure of a roadbed uneven settlement monitoring system with a retrospective positioning function proposed by the utility model;

[0031] Figure 4 This is a schematic diagram of the cross-section of a distributed optical cable material in a roadbed uneven settlement monitoring system with a traceability positioning function proposed by the utility model;

[0032] Figure 5 This is a plan view schematic diagram of the laying of distributed optical cables in a roadbed uneven settlement monitoring system with a traceability positioning function proposed by the utility model.

[0033] In the figure: 1-distributed optical cable; 11-distributed strain sensing optical fiber; 12-GPS transmission line; 13-coating layer; 14-inner sheath; 15-outer sheath; 16-reinforced steel wire; 2-GPS sensor; 3-optical fiber sensor demodulator; 4-GPS receiver; 5-data storage device; 6-photovoltaic power supply device; 7-first protective sand layer; 8-second protective sand layer; a-roadbed; b-foundation. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0035] Combination Figures 1 to 4 As shown, the embodiment of the utility model provides a roadbed uneven settlement monitoring system with a retroactive positioning function, which aims to achieve real-time monitoring and retroactive positioning of roadbed settlement through advanced distributed optical fiber sensing technology and GPS positioning technology. The settlement monitoring system mainly includes a distributed optical cable 1, a GPS sensor 2, an optical fiber sensor demodulator 3, a GPS receiver 4 and a data storage device 5, and the specific layout and connection are as follows:

[0036] like Figure 1 As shown, several distributed optical cables 1 are laid in a crisscross pattern in the roadbed a to ensure that the optical cables cover the entire monitoring area. Figure 4 As shown, each distributed optical cable 1 includes a distributed strain sensing optical fiber 11 and a GPS transmission line 12, wherein the distributed strain sensing optical fiber 11 is used for strain monitoring, and the GPS transmission line 12 is used for GPS signal transmission.

[0037] like Figure 1 As shown, several GPS sensors 2 are arranged at the intersection of the crisscross distributed optical cables 1. In other words, GPS sensors 2 are installed at the intersection of the crisscross distributed optical cables 1. Each GPS sensor 2 is connected to the GPS transmission line 12 at the corresponding position to ensure the stable transmission of GPS signals.

[0038] like Figure 1 As shown, the optical fiber sensor demodulator 3 is connected to the distributed strain sensing optical fiber 11 to demodulate the optical fiber sensing signal and obtain the roadbed strain data. The GPS receiver 4 is connected to the GPS transmission line 12 to receive the positioning information sent by the GPS sensor 2. The data storage device 5 is connected to the optical fiber sensor demodulator 3 and the GPS receiver 4 to store the strain data and GPS positioning information in real time.

[0039] It should be understood that when laying the distributed optical cables 1 and the GPS sensors 2, the actual positions of each distributed optical cable 1 and each GPS sensor 2 in the roadbed a are calibrated, that is, it is known where each distributed optical cable 1 and each GPS sensor 2 are located in the roadbed a, and these calibration data are recorded and saved for comparison with the data collected by the system during subsequent monitoring, so as to determine the settlement position.

[0040] Specifically, the principle of using the monitoring system provided in this embodiment to monitor roadbed settlement is as follows: when the roadbed settles, the distributed strain sensing optical fiber 11 corresponding to the location where the settlement occurs can monitor the strain information, and the strain information is demodulated by the optical fiber sensor demodulator 3 and sent to the data storage device 5. At the same time, the position of the GPS sensor 2 corresponding to the location where the settlement occurs will change. The GPS receiver 4 receives the GPS positioning information of the GPS sensor 2 through the GPS transmission line 12 and sends it to the data storage device 5. Researchers use the strain data and GPS positioning information stored in the data storage device 5, and combine them with the positions of each distributed optical cable 1 and each GPS sensor 2 in the roadbed a to determine the location where the settlement occurs.

[0041] It should be noted that the judgment process of the settlement position can be completed by researchers manually comparing data. Preferably, these data are configured to a computer, which can quickly complete the comparison and analysis and generate a roadbed settlement monitoring report to provide decision support for roadbed maintenance and management.

[0042] For example, Figure 5As shown, several distributed optical cables 1 and GPS sensors 2 are laid along the horizontal and vertical directions of the roadbed a, and the distributed optical cables 1 and GPS sensors are numbered. From the initial position to the final position, the distributed optical cables 1 laid horizontally are named “HJ01, HJ02, HJ03…”, and the distributed optical cables 1 laid vertically are named “ZJ01, ZJ02, ZJ03…”, and the GPS sensors 2 set at the junction are named “HZ11, HZ12, HZ13…HZ21, HZ22, HZ23…”. For example, when the distributed strain sensing optical fiber 11 in the distributed optical cable 1 ZJ01 detects strain information, it means that the location of the optical cable has subsided. At this time, the positioning information of some or all of the GPS sensors 2 located on the optical cable will inevitably change. By combining the strain information and the positioning information, the location where the subsidence occurred can be quickly determined. For example, if the positioning information of the two GPS sensors 2 HZ11 and HZ12 changes, it can be known that the position between the two GPS sensors has subsided.

[0043] In this embodiment, the optical fiber sensor demodulator 3 and the GPS receiver 4 are connected to the distributed optical cable 1 through the optical cable external lead wire to realize the collection of deformation data and position information.

[0044] In one embodiment, if Figures 1 to 3 As shown, the monitoring system also includes a power supply device 6, which is electrically connected to the optical fiber sensor demodulator 3 and the GPS receiver 4 to ensure that these two core components can obtain a stable and continuous power supply. It should be noted that the power supply device 6 should have safety functions such as overvoltage protection and overcurrent protection to ensure the stability and safety of the system operation. According to actual needs, the power supply device 6 can be powered by AC power, solar power or battery power to meet the monitoring needs in different environments.

[0045] Preferably, the power supply device 6 adopts an efficient and environmentally friendly photovoltaic power supply device, which converts solar energy into electrical energy to provide a stable and continuous power supply for the optical fiber sensor demodulator 3 and the GPS receiver 4. The photovoltaic power supply device should have an intelligent charging management function to ensure the charging efficiency and battery life of the system battery. Considering the diversity of the roadbed monitoring environment, the design of the photovoltaic power supply device should have good waterproof and dustproof performance to adapt to harsh outdoor environments.

[0046] In one possible implementation, Figure 2 and Figure 3As shown, the distributed optical cable 1 and the GPS sensor 2 are physically protected. A first protective sand layer 7 is laid under the distributed optical cable 1. The sand layer can effectively isolate the optical cable from the roadbed soil below to prevent the optical cable from being damaged by soil pressure or movement. A second protective sand layer 8 is laid above the distributed optical cable 1. The sand layer also plays an isolation and protection role to prevent the traffic load or environmental factors above from damaging the optical cable. The GPS sensor 2 is cleverly placed between the first protective sand layer 7 and the second protective sand layer 8, which can ensure close contact between the sensor and the roadbed soil to accurately measure the settlement data, and can effectively isolate the sensor from external physical impact or damage through the two layers of protective sand layers. Exemplarily, the thickness of the first protective sand layer 7 and the second protective sand layer 8 are both 3 cm.

[0047] Preferably, by adjusting the layout density of the distributed optical cables 1 to ensure the accuracy and comprehensiveness of monitoring, the distance between two adjacent distributed optical cables 1 along the transverse direction of the roadbed a is 5m to 10m; along the longitudinal direction of the roadbed a, the distance between two adjacent distributed optical cables 1 is 10m to 50m. Such a layout density design is intended to ensure that the monitoring system can capture every subtle settlement change on the roadbed a, thereby improving the accuracy and reliability of monitoring. At the same time, the layout density can also effectively control the monitoring cost and achieve the best cost performance while ensuring the monitoring quality.

[0048] In one possible implementation, Figure 4 As shown, each distributed optical cable 1 also includes a coating layer 13, an inner sheath 14, an outer sheath 15 and a reinforcing steel wire 16. The coating layer 13 is coated on the outer surface of the distributed strain sensing optical fiber 11 and the outer surface of the GPS transmission line 12, providing a first layer of protection to prevent the optical fiber and the transmission line from being directly corroded by the external environment. The inner sheath 14 is coated on the outer surface of the coating layer 13 as a second layer of protection to further enhance the compression and tensile strength of the optical cable. The outer sheath 15 is coated on the outer surface of the inner sheath 14 as the outermost layer of protection. The reinforcing steel wire 16 is arranged in the outer sheath 15 to enhance the overall strength of the optical cable and prevent it from being broken or damaged during construction or use. Each distributed optical cable 1 has durability and stability, and can work stably for a long time in various harsh environments, providing reliable data support for monitoring uneven subsidence of roadbed.

[0049] In one embodiment, wireless communication is adopted between the data storage device 5 and the optical fiber sensor demodulator 3 and the GPS receiver 4 to achieve real-time and efficient data transmission. Wireless communication not only improves the speed and accuracy of data transmission, but also greatly simplifies the wiring complexity of the system and reduces maintenance costs. At the same time, wireless communication also enhances the flexibility and scalability of the system, making it easier for the system to adapt to different monitoring environments and requirements.

[0050] For example, the installation process of a roadbed uneven settlement monitoring system with retrospective positioning function is as follows:

[0051] Step S1: fill the roadbed a and lay the distributed optical cable 1; according to the roadbed filling requirements, fill the roadbed on the foundation b to the bottom design elevation. Lay a 3cm thick first protective sand layer 7 at the pre-installation position of the distributed optical cable 1 and the GPS sensor 2. Lay a number of distributed optical cables 1 and GPS sensors 2 horizontally and vertically along the roadbed, and number the distributed optical cables 1 and GPS sensors 2. From the initial position to the final position, the horizontally laid optical cables are named "HJ01, HJ02, HJ03...", and the longitudinally laid optical cables are named "ZJ01, ZJ02, ZJ03...". GPS sensors are set at the junction and named "HZ11, HZ12, HZ13...HZ21, HZ22, HZ23..."

[0052] Step S2: Install the fiber optic sensor demodulator 3 and the GPS receiver 4; the fiber optic sensor demodulator 3 and the GPS receiver 4 are placed in an equipment box, which is used to protect the instruments. The power supply device 6 is powered by a photovoltaic panel and is installed on the upper surface of the equipment box.

[0053] Step S3: Connect the distributed optical cable 1 and the GPS sensor 2; connect the distributed optical cable 1, the GPS sensor 2, the optical fiber sensor demodulator 3 and the GPS receiver 4 through the optical cable external lead wires laid along the longitudinal section of the roadbed. A 3 cm thick second protective sand layer 8 is laid on the upper part of the installed optical cable and GPS sensor to protect the distributed optical cable 1 and the GPS sensor 2 from being damaged by the construction, and the surface filling of the base bed is completed at the same time.

[0054] In this embodiment, the GPS receiver 4 collects GPS signals, the optical fiber sensor demodulator 3 receives the roadbed settlement monitoring data along each distributed strain sensing optical fiber 11 and the position data of the distributed optical cable 1, and the deformation data along the roadbed is associated with the corresponding GPS position data. The monitoring system monitors whether there is abnormal settlement by analyzing the processed data. When an abnormality is detected, the system records the time point when the abnormality occurs and the location information of the preliminary positioning. Based on the location information of the preliminary positioning, combined with the real-time location information recorded by the GPS sensor, the specific location when the abnormal settlement occurs is traced back. When the system detects abnormal settlement and successfully traces the location, it triggers the alarm mechanism and sends an alarm message to the relevant personnel of the data monitoring center.

[0055] It should be noted that the specific location and quantity of the distributed optical cable 1 and GPS sensor 2 can be adjusted comprehensively according to the actual project monitoring section location requirements, monitoring accuracy, site conditions and other factors. They can be laid in the base or surface layer of the roadbed a, and the thickness of the laid fine sand protection layer should be determined comprehensively according to multiple factors such as the cable burial depth, roadbed conditions, load conditions, etc. The system can adjust the data collection interval as needed.

[0056] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0057] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0058] In the present invention, unless otherwise clearly defined and limited, the terms "connected", "connection" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0060] In the present utility model, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0061] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the utility model, which are used to illustrate the technical solution of the utility model, rather than to limit it. The protection scope of the utility model is not limited thereto. Although the utility model is described in detail with reference to the above-mentioned embodiments, ordinary technicians in this field should understand that any technician familiar with the technical field can still modify the technical solution recorded in the above-mentioned embodiments within the technical scope disclosed by the utility model, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiment of the utility model, and should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model shall be based on the protection scope of the claims.

Claims

1. A roadbed uneven settlement monitoring system with retrospective positioning function, characterized in that: include: A plurality of distributed optical cables (1) are arranged in a crisscross pattern in a roadbed (a), each of the distributed optical cables (1) comprising a distributed strain sensing optical fiber (11) and a GPS transmission line (12); A plurality of GPS sensors (2) are arranged at the intersection of the crisscrossing distributed optical cables (1), and each of the GPS sensors (2) is connected to the GPS transmission line (12) at a corresponding position; An optical fiber sensing demodulator (3) connected to the distributed strain sensing optical fiber (11); A GPS receiver (4) connected to the GPS transmission line (12); A data storage device (5) is connected to the optical fiber sensor demodulator (3) and the GPS receiver (4).

2. A roadbed uneven settlement monitoring system with retrospective positioning function according to claim 1, characterized in that: The monitoring system also includes: A power supply device (6) is electrically connected to the optical fiber sensor demodulator (3) and the GPS receiver (4).

3. The roadbed uneven settlement monitoring system with retrospective positioning function according to claim 2 is characterized in that: The power supply device (6) is a photovoltaic power supply device.

4. The roadbed uneven settlement monitoring system with retrospective positioning function according to claim 1 is characterized in that: A first protective sand layer (7) is laid below the distributed optical cable (1), a second protective sand layer (8) is laid above the distributed optical cable (1), and the GPS sensor (2) is located between the first protective sand layer (7) and the second protective sand layer (8).

5. The roadbed uneven settlement monitoring system with retrospective positioning function according to claim 1 is characterized in that: Along the transverse direction of the roadbed (a), the distance between two adjacent distributed optical cables (1) is 5m to 10m.

6. A roadbed uneven settlement monitoring system with retrospective positioning function according to claim 5, characterized in that: Along the longitudinal direction of the roadbed (a), the distance between two adjacent distributed optical cables (1) is 10m to 50m.

7. The roadbed uneven settlement monitoring system with retrospective positioning function according to claim 1 is characterized in that: Each of the distributed optical cables (1) further comprises: A coating layer (13) covering the outer surface of the distributed strain sensing optical fiber (11) and the outer surface of the GPS transmission line (12); An inner sheath (14) covering the outer surface of the coating layer (13); An outer sheath (15) covering the outer surface of the inner sheath (14); A reinforcing steel wire (16) is arranged in the outer sheath (15).

8. The roadbed uneven settlement monitoring system with retrospective positioning function according to claim 1 is characterized in that: The data storage device (5) uses wireless communication with the optical fiber sensor demodulator (3) and the GPS receiver (4).

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