Deformation monitoring system and method based on distributed optical fiber or arrayed grating optical fiber

Abstract

This invention discloses a deformation monitoring system and method based on distributed optical fiber or arrayed grating optical fiber, relating to the field of deformation measurement technology. It can at least partially solve the problem of long-term real-time monitoring of deformation of ground, seabed, three-dimensional buildings, or three-dimensional columnar objects in the prior art. The deformation monitoring system based on distributed deformation sensing optical fiber or arrayed grating optical fiber in the embodiments of this invention includes a composite modulation and demodulation instrument with a distributed optical fiber deformation sensing port, and several deformation measurement or monitoring armored optical cables uniformly covering and fixed to the measurement or monitoring target. The deformation measurement or monitoring armored optical cables include distributed deformation sensing optical fibers or arrayed deformation sensing grating optical fibers for transmitting deformation sensing signals to the composite modulation and demodulation instrument in real time. The distributed optical fiber deformation sensing port of the composite modulation and demodulation instrument is connected to the distributed deformation sensing optical fibers or arrayed deformation sensing grating optical fibers of the deformation measurement or monitoring armored optical cables.

Description

Technical Field

[0001] This invention belongs to the field of deformation measurement technology, specifically relating to a deformation monitoring system and method based on distributed optical fiber or arrayed grating optical fiber. Background Technology

[0002] Fiber optic sensing technology originated in 1977 and has developed rapidly alongside fiber optic communication technology. It is an important indicator of a country's level of informatization. Fiber optic sensing technology is widely used in military, defense, aerospace, industrial and mining enterprises, energy and environmental protection, industrial control, medicine and health, metrology and testing, construction, and home appliances. Currently, there are hundreds of fiber optic sensing technologies, enabling the sensing of physical quantities such as temperature, pressure, flow rate, displacement, vibration, rotation, bending, liquid level, velocity, acceleration, sound field, current, voltage, magnetic field, and radiation with varying performance.

[0003] Land subsidence is a geological phenomenon caused by ground or seabed deformation, and it is a form of geological deformation. Land subsidence can be natural or anthropogenic. It is a destructive phenomenon and process caused by internal or external geological dynamics or human activities, resulting in changes in the landform. If land subsidence causes economic losses or casualties, it becomes a geological hazard. Examples include mountain uplift or basin subsidence caused by tectonic movements, groundwater extraction, and mining, which are caused by human activities such as ground fissures, land subsidence, and collapses. With the intensification of human activities, anthropogenic factors have become a significant cause of land subsidence and geological hazards.

[0004] Crustal deformation refers to the phenomena and corresponding changes in the Earth's crustal surface, such as uplift, tilting, and faulting, caused by internal and external forces. Repeated or continuous observation of the relative changes in the Earth's crustal surface in a region is called crustal deformation measurement, which includes global plate movement monitoring, national and regional crustal deformation measurement, fault deformation measurement, and point-based deformation measurement.

[0005] Ground deformation measurement mainly includes ground subsidence and seismic deformation monitoring. Currently, the main methods used in traditional ground deformation measurement include leveling, GPS, and Synthetic Aperture Radar Interferometry (InSAR). Crustal deformation observation can be performed through instrumental measurements, such as using lasers to measure changes in distance between surface markers and using levels to measure changes in elevation between fixed ground points. These data provide a basis for earthquake prediction. Direct observation of crustal deformation is of great significance in studying geodynamics, tectonic movements, crustal stability assessment, and the role of crustal deformation in earthquake formation.

[0006] With the development of optical technology, optical measurement methods have emerged for measuring the deformation of ground or structural surfaces. Optical measurement methods apply optical principles and experimental techniques to study mechanical quantities such as stress, strain, displacement, and deformation in structures. These methods include photoelasticity, holographic interferometry, laser speckle interferometry, and moiré pattern methods. Fiber optic deformation measurement uses optical fibers as the sensing medium. Utilizing optical principles and techniques, it measures the changes in optical parameters such as intensity, phase, polarization state, and wavelength of light caused by external factors (such as stretching, compression, and deformation) to measure the deformation of the object being measured.

[0007] In addition, quasi-distributed fiber optic sensors, such as fiber Bragg grating (FBG) sensors, have emerged. However, the measurement points of FBG sensors are limited by the laser bandwidth. Distributed fiber optic sensing technology is maturing, and distributed fiber optic sensors based on backscattering Rayleigh scattering exhibit good accuracy, linearity, and repeatability in deformation measurement, showing the potential to replace traditional deformation measurement technologies and FBG sensors in many fields. Distributed fiber optic sensors feature extremely high measurement point density, controllable spacing, small mass, corrosion resistance, electrical insulation, high accuracy, and good repeatability. Furthermore, due to their relatively soft and tough properties, they have good adaptability to the shape of structural surfaces. Summary of the Invention

[0008] The purpose of this invention is to propose a deformation monitoring system and method based on distributed optical fiber or arrayed grating optical fiber. This involves burying a deformation measurement or monitoring armored optical cable, composed of distributed deformation sensing optical fiber or high-density arrayed deformation sensing grating optical fiber, in a mesh-like pattern below ground or seabed, or fixing it to the outer surface of buildings or large-scale foundation engineering structures requiring deformation monitoring, or directly wrapping it around the outer surface of columnar objects such as pipelines. This allows the armored optical cable to be connected to a composite modulation and demodulation instrument, forming a deformation monitoring system based on distributed optical fiber or high-density arrayed grating sensing. This overcomes the shortcomings of existing high-density, high-resolution deformation measurement technologies for ground, seabed, building structures, or columnar objects such as pipelines. It enables long-term, real-time monitoring and measurement of potential damage or destruction caused by deformation on the outer surfaces of ground, seabed, large-scale foundation engineering structures, and columnar objects such as pipelines. This provides an indispensable means, system, and method to ensure the long-term stable, safe, and reliable operation of ground, seabed, large-scale foundation engineering structures, pipelines, and other facilities.

[0009] To achieve the above objectives, the specific technical solution of the present invention is as follows:

[0010] This invention proposes a deformation monitoring system based on distributed optical fiber or arrayed grating optical fiber, including a composite modulation and demodulation instrument with a distributed optical fiber deformation (DSS) sensing port, and several deformation measurement or monitoring armored optical cables uniformly covered and fixed on the measurement or monitoring target. The deformation measurement or monitoring armored optical cables include distributed deformation sensing optical fibers or arrayed deformation sensing grating optical fibers for transmitting deformation (DSS) sensing signals to the composite modulation and demodulation instrument in real time. The distributed optical fiber deformation (DSS) sensing port of the composite modulation and demodulation instrument is connected to the distributed deformation sensing optical fibers or arrayed deformation sensing grating optical fibers of the deformation measurement or monitoring armored optical cables.

[0011] In some alternative embodiments, the composite modem has a distributed fiber temperature (DTS) sensing port, and the deformation measurement or monitoring armored optical cable includes two multimode optical fibers for measuring temperature changes along its length. The ends of the two multimode optical fibers are fused together into a U-shaped structure, and the two distributed fiber temperature (DTS) sensing ports of the composite modem are connected to the two multimode optical fibers of the deformation measurement or monitoring armored optical cable.

[0012] In some optional embodiments, the distributed deformation sensing fiber of the armored optical cable for deformation measurement or monitoring includes a bend-insensitive deformation sensing fiber, which is a single-mode fiber or a special deformation-sensitive fiber.

[0013] In some alternative embodiments, the deformation measurement or monitoring armored optical cable further includes a sheath for wrapping the bend-insensitive deformation sensing optical fiber, and a continuous stainless steel tube for wrapping the sheath and the multimode optical fiber.

[0014] In some optional embodiments, the array deformation sensing grating fiber of the deformation measurement or monitoring armored optical cable includes a cladding, a core, a high-density array grating inscribed on the core, and a multi-core grating; wherein the inscription density of the high-density array grating is between 1 meter and 10 meters.

[0015] In some optional embodiments, the measurement or monitoring target is a two-dimensional or three-dimensional measurement or monitoring target area located on the surface or seabed. A number of deformation measurement or monitoring armored optical cables form a two-dimensional or three-dimensional deformation measurement or monitoring network adapted to the monitoring target. The two-dimensional or three-dimensional deformation measurement or monitoring network is buried in the two-dimensional or three-dimensional measurement or monitoring target area on the surface or seabed by digging trenches. The shape of the two-dimensional or three-dimensional deformation measurement or monitoring network includes any one of rectangular grid or concentric circle.

[0016] In some optional embodiments, the measurement or monitoring target is a three-dimensional building with different deformation magnitudes and directions. Several deformation measurement or monitoring armored optical cables form a three-dimensional building deformation measurement or monitoring network. The deformation measurement or monitoring armored optical cables of the three-dimensional building deformation measurement or monitoring network are all fixed parallel to the outer surface of the three-dimensional building along the direction of larger deformation.

[0017] In some optional embodiments, the target for measurement or monitoring is a cylindrical three-dimensional column, and the deformation measurement or monitoring armored optical cable is tightly wound and fixed to the outer surface of the three-dimensional column in a spiral shape to form a spiral deformation measurement or monitoring network.

[0018] Another aspect of the present invention provides a deformation monitoring method based on distributed optical fiber or arrayed grating optical fiber, applicable to any of the above-described deformation monitoring systems based on distributed optical fiber or arrayed grating optical fiber, specifically including the following steps:

[0019] S1: Connect the first end of the distributed optical fiber or array deformation sensing grating optical fiber of the deformation measurement or monitoring armored optical cable to the deformation sensing (DSS) optical fiber signal input end of the composite modem instrument, and connect the first ends of the two multimode optical fibers of the deformation measurement or monitoring armored optical cable to the temperature sensing (DTS) dual-ended optical fiber signal input end of the composite modem instrument.

[0020] S2: Start the composite modulation and demodulation instrument to perform real-time deformation modulation and demodulation on the deformation measurement or monitoring armored optical cable deployed on the outer surface of underground or seabed or large foundation structure or pipeline. At the same time, it also performs real-time temperature change signal modulation and demodulation on the two multimode optical fibers.

[0021] S3: Load the coordinates of each deformation measurement or monitoring armored optical cable onto a 3D topographic map or 3D stereoscopic map, where:

[0022] The coordinates of armored optical cables buried on the ground or seabed for deformation measurement or monitoring need to be loaded onto a three-dimensional topographic map of the area covered by the two-dimensional or three-dimensional deformation measurement or monitoring network.

[0023] The coordinates of armored optical cables fixed to the outer surface of a three-dimensional building for deformation measurement or monitoring need to be loaded onto a three-dimensional model of the building's structural surface.

[0024] The coordinates of armored optical cables that are spirally wound and fixed to the outer surface of a three-dimensional column need to be loaded onto a three-dimensional columnar graph on the outer surface of the three-dimensional column.

[0025] S4: The deformation data of each deformation measurement or monitoring armored optical cable, which is modulated and demodulated in real time by the composite modulation and demodulation instrument, is corrected for temperature drift based on the temperature change along the deformation measurement or monitoring armored optical cable, and the corrected deformation data of the deformation measurement or monitoring armored optical cable after temperature drift is input and displayed in real time on the three-dimensional topographic map, three-dimensional stereo map or three-dimensional columnar plot.

[0026] S5: Perform three-dimensional surface interpolation on the real-time deformation data of the armored optical cable after temperature drift correction for deformation measurement or monitoring, and display the deformation data after three-dimensional surface interpolation on a three-dimensional topographic map, three-dimensional stereo map or three-dimensional columnar plot with different color marks in real time.

[0027] S6: To conduct comprehensive analysis of real-time measurement or monitoring data of three-dimensional deformation of the ground and seabed, and to conduct real-time long-term deformation measurement or monitoring of fluid changes in underground or seabed oil and gas reservoirs and the injection and extraction status of oil and gas resources in gas and oil storage facilities, as well as to conduct measurement or monitoring of natural earthquakes, collapses, subsidence or landslides based on real-time long-term deformation measurement or monitoring data of the ground or seabed caused by changes in the geostress field below the ground or seabed, and to issue early warnings or alarms in a timely manner.

[0028] S7: To conduct real-time long-term measurement or monitoring of the three-dimensional deformation of the outer surface of a three-dimensional building, so as to measure or monitor the potential risk of damage to the three-dimensional building structure caused by geological disasters under the three-dimensional building structure in real time, and to issue early warnings or alarms in a timely manner.

[0029] S8: To perform real-time long-term measurement or monitoring of the three-dimensional deformation of the outer surface of a cylindrical three-dimensional columnar object, so as to measure or monitor the potential risk of damage to the structure of the three-dimensional columnar object caused by geological disasters under the object in real time, and to issue early warnings or alarms in a timely manner.

[0030] In some optional embodiments, prior to step S1, the following steps are also included:

[0031] Step S0: Cover and fix several deformation measurement or monitoring armored optical cables to the monitoring target;

[0032] When measuring or monitoring ground deformation, according to the design of the ground deformation measurement or monitoring network, shallow trenches are dug along the two-dimensional or three-dimensional survey lines on the ground, and the armored optical cable for deformation measurement or monitoring is laid to the bottom of the trench and then fixed below the ground surface with cement.

[0033] When measuring or monitoring seabed deformation, shallow trenches are excavated along two-dimensional or three-dimensional survey lines on the seabed according to the design of the seabed deformation measurement or monitoring network, and armored optical cables for deformation measurement or monitoring are laid and buried at the bottom of the trenches.

[0034] When measuring or monitoring the deformation of a three-dimensional building, it is necessary to use optical cable fixing clips, fixing strips, or fixing cement to firmly fix the armored optical cable for deformation measurement or monitoring to the outer surface of the three-dimensional building where deformation monitoring is required.

[0035] When measuring or monitoring the deformation of a cylindrical three-dimensional column, the deformation measurement or monitoring armored optical cable needs to be tightly wound and fixed to the outer surface of the three-dimensional column in a spiral shape.

[0036] The beneficial effects of this invention are:

[0037] This invention proposes to bury armored optical cables composed of distributed optical fibers or high-density array gratings in a mesh-like pattern below the ground or seabed, or fix them to the outer surface of three-dimensional building structures requiring deformation monitoring, or wrap them around the outer surface of three-dimensional columnar objects such as pipelines. These cables are then connected to the deformation sensing (DSS) optical fiber signal input end and the temperature sensing (DTS) dual-ended optical fiber signal input end of a composite modulation and demodulation instrument, forming a deformation monitoring system based on distributed optical fiber or high-density array grating sensing. This system can be effectively applied to the monitoring of deformation on the ground and seabed, the structural health status of buildings and large-scale foundation engineering projects, and the monitoring of the safety of three-dimensional columnar structures. It provides a low-cost, high-density, high-precision, and high-reliability dynamic monitoring method and technology for the deformation distribution changes of ground or seabed or three-dimensional buildings or three-dimensional columnar objects. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of an armored optical cable for deformation measurement or monitoring that includes distributed optical fibers, as described in an embodiment of the present invention.

[0039] Figure 2 This is a schematic diagram of the structure of a high-density array deformation sensing grating fiber in an armored optical cable for deformation measurement or monitoring, according to another embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram of the deployment of armored optical cables for deformation measurement or monitoring in a grid pattern covering the earth's surface or seabed in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the deployment of armored optical cables for deformation measurement or monitoring in a concentric circle pattern covering the earth's surface or seabed in an embodiment of the present invention.

[0042] Figure 5 This is a schematic diagram of the deployment of armored optical cables for deformation measurement or monitoring, which are fixed to the outer surface of a three-dimensional building in an embodiment of the present invention.

[0043] Figure 6 This is a schematic diagram of the layout of the armored optical cable for deformation measurement or monitoring, which is spirally wound and fixed to the outer surface of a three-dimensional column in an embodiment of the present invention.

[0044] Figure label:

[0045] 1-Two-dimensional or three-dimensional deformation measurement or monitoring network; 2-Three-dimensional building deformation measurement or monitoring network; 3-Helical deformation measurement or monitoring network; 4-Composite modulation and demodulation instrument; 5-Deformation measurement or monitoring armored optical cable; 20-Cladding; 21-Fiber core; 22-High-density array grating; 23-Multi-core grating; 51-Bend-insensitive deformation sensing fiber; 52-Sheath; 53-Multimode fiber; 54-Stainless steel tube; 55-U-shaped structure. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0047] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "longitudinal," "lateral," "horizontal," "inner," "outer," "front," "rear," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "have," "install," "connect," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0050] like Figures 1 to 6As shown, this embodiment provides a deformation monitoring system based on distributed optical fiber or arrayed grating optical fiber. It includes a composite modem 4 with a distributed shape sensing (DSS) port and several deformation measurement or monitoring armored optical cables 5 uniformly covered and fixed on the target being measured or monitored. The deformation measurement or monitoring armored optical cables 5 include distributed deformation sensing optical fibers or arrayed deformation sensing grating optical fibers for transmitting deformation (DSS) sensing signals to the composite modem 4 in real time. The distributed optical fiber deformation (DSS) sensing port of the composite modem 4 is connected to the distributed deformation sensing optical fibers or arrayed deformation sensing grating optical fibers of the deformation measurement or monitoring armored optical cables 5. In this embodiment, the composite modem 4 has distributed temperature sensing modulation and demodulation functions as well as distributed optical fiber deformation modulation and demodulation or high-density arrayed grating 22 deformation modulation and demodulation functions. In this embodiment, the deformation measurement or monitoring armored optical cables 5 are armored optical cables with deformation measurement or deformation monitoring functions.

[0051] In some optional embodiments, the composite modulation and demodulation instrument 4 has a distributed fiber temperature (DTS) sensing port, and the deformation measurement or monitoring armored optical cable 5 includes two multimode optical fibers 53 for measuring temperature changes along its length. The tail ends of the two multimode optical fibers 53 are fused into a U-shaped structure 55, and the two distributed fiber temperature (DTS) sensing ports of the composite modulation and demodulation instrument 4 are connected to the two multimode optical fibers 53 of the deformation measurement or monitoring armored optical cable 5.

[0052] In some alternative embodiments, such as Figure 1 As shown, the distributed optical fiber of the armored optical cable 5 for deformation measurement or monitoring includes a bend-insensitive deformation sensing fiber 51, which is a single-mode fiber or a special deformation-sensitive fiber.

[0053] In some alternative embodiments, the deformation measurement or monitoring armored optical cable 5 further includes a sheath 52 for wrapping the bend-insensitive deformation sensing optical fiber 51, and a continuous stainless steel tube 54 for wrapping the sheath 52 and the multimode optical fiber 53.

[0054] In some alternative embodiments, such as Figure 2As shown, the deformation measurement or monitoring armored optical cable 5 comprises a cladding 20, a fiber core 21, a high-density array grating 22 inscribed on the fiber core 21, and a multi-core grating 23; wherein the inscription density of the high-density array grating 22 is between 1 meter and 10 meters. For the measurement or monitoring of large-scale underground or seabed deformation targets, the inscription density of the array grating can be between 5 meters and 10 meters. For the measurement or monitoring of small-scale underground or seabed deformation targets, the inscription density of the array grating can be between 1 meter and 3 meters. The measurement or monitoring armored optical cable fabricated with a high-density inscribed array grating has higher deformation measurement or monitoring accuracy and sensitivity.

[0055] In some alternative embodiments, such as Figure 3 and Figure 4 As shown, the measurement or monitoring target is a two-dimensional or three-dimensional measurement or monitoring target area located on the surface or seabed. Several deformation measurement or monitoring armored optical cables 5 form a two-dimensional or three-dimensional deformation measurement or monitoring network 1 adapted to the monitoring target. The two-dimensional or three-dimensional deformation measurement or monitoring network 1 is buried in the two-dimensional or three-dimensional measurement or monitoring target area on the surface or seabed by digging trenches. The shape of the two-dimensional or three-dimensional deformation measurement or monitoring network 1 includes either a rectangular grid or concentric circles. After burying the two-dimensional or three-dimensional deformation measurement or monitoring network 1 in a shallow trench on the surface, it is then fixed with cement. In this embodiment, for two-dimensional or three-dimensional measurement or monitoring target areas located on the surface or seabed, the effect of arranging the two-dimensional or three-dimensional deformation measurement or monitoring network 1 in a rectangular grid or concentric circles is not significantly different; the main consideration is the ease of installation and deployment.

[0056] In some alternative embodiments, such as Figure 5 As shown, the target of measurement or monitoring is a three-dimensional building with varying deformation magnitudes and directions. Several armored optical cables 5 for deformation measurement or monitoring form a three-dimensional building deformation measurement or monitoring network 2. All armored optical cables 5 in the three-dimensional building deformation measurement or monitoring network 2 are fixed parallel to the outer surface of the three-dimensional building along the direction of greater deformation. In this embodiment, the three-dimensional building can be a large-scale foundation engineering structure.

[0057] In some alternative embodiments, such as Figure 6 As shown, the target for measurement or monitoring is a cylindrical three-dimensional columnar object. The deformation measurement or monitoring armored optical cable 5 is tightly wound and fixed in a spiral shape to the outer surface of the three-dimensional columnar object to form a spiral deformation measurement or monitoring network 3. In this embodiment, the three-dimensional columnar object can be a cylindrical columnar object such as a pipeline.

[0058] Another aspect of the present invention provides a deformation monitoring method based on distributed optical fiber or arrayed grating optical fiber, applicable to any of the above-described deformation monitoring systems based on distributed optical fiber or arrayed grating optical fiber, specifically including the following steps:

[0059] S1: Connect the first end of the distributed deformation sensing fiber or array deformation sensing grating fiber of the deformation measurement or monitoring armored optical cable 5 to the deformation sensing (DSS) fiber signal input end of the composite modem 4, and connect the first ends of the two multimode fibers 53 of the deformation measurement or monitoring armored optical cable 5 to the temperature sensing (DTS) dual-ended fiber signal input end of the composite modem 4.

[0060] S2: Start the composite modulation and demodulation instrument 4 to perform real-time deformation modulation and demodulation on the deformation measurement or monitoring armored optical cable 5 laid on the outer surface of underground or seabed or large foundation structure or pipeline. At the same time, the real-time temperature change signal along the line is also modulated and demodulated on the two multimode optical fibers 53.

[0061] S3: Load the coordinates of each deformation measurement or monitoring armored optical cable 5 onto a three-dimensional topographic map or three-dimensional stereoscopic map, where:

[0062] The coordinates of armored optical cables 5 buried on the ground or seabed for deformation measurement or monitoring need to be loaded onto a three-dimensional topographic map of the area covered by the two-dimensional or three-dimensional deformation measurement or monitoring network 1.

[0063] The deformation measurement or monitoring of armored optical cables fixed to the outer surface of a three-dimensional building requires the coordinates to be loaded onto a three-dimensional model of the building's structural surface.

[0064] The deformation measurement or monitoring of armored optical cables that are spirally wound and fixed to the outer surface of a three-dimensional columnar object requires the coordinates to be loaded onto a three-dimensional columnar graph on the outer surface of the three-dimensional columnar object.

[0065] S4: The deformation data of each deformation measurement or monitoring armored optical cable 5, which is modulated and demodulated in real time by the composite modulation and demodulation instrument 4, is corrected for temperature drift of the optical cable based on the temperature change along the deformation measurement or monitoring armored optical cable 5, and the corrected deformation data along the deformation measurement or monitoring armored optical cable 5 after temperature drift is input and displayed in real time on the three-dimensional topographic map, three-dimensional stereo map or three-dimensional columnar plot.

[0066] S5: Perform three-dimensional surface interpolation processing on the real-time deformation data of the armored optical cable 5 after temperature drift correction for deformation measurement or monitoring, and display the deformation data after three-dimensional surface interpolation processing on a three-dimensional topographic map, three-dimensional stereo map or three-dimensional columnar plot with different color marks in real time; there are many mathematical methods for three-dimensional surface interpolation processing in this field, which will not be elaborated here.

[0067] S6: To conduct comprehensive analysis of real-time measurement or monitoring data of three-dimensional deformation of the ground and the seabed, and to conduct real-time long-term deformation measurement or monitoring of fluid changes in underground or seabed oil and gas reservoirs and the injection and extraction status of oil and gas resources in gas and oil storage facilities, as well as to conduct measurement or monitoring of natural earthquakes, collapses, subsidence or landslides based on real-time long-term deformation measurement or monitoring data of the ground or seabed caused by changes in the geostress field below the ground or seabed, and to issue early warnings or alarms in a timely manner.

[0068] S7: Real-time long-term measurement or monitoring of three-dimensional deformation of the outer surface of a three-dimensional building, in order to measure or monitor the potential risks of damage to the three-dimensional building structure caused by ground deformation below the three-dimensional building structure or geological disasters such as landslides, mudslides, floods or heavy rainstorms, and to issue early warnings or alarms in a timely manner.

[0069] S8: Real-time long-term measurement or monitoring of the three-dimensional deformation of the outer surface of a cylindrical three-dimensional columnar object, in order to measure or monitor the potential risks of damage to the structure of the three-dimensional columnar object caused by ground deformation below the object, landslides, mudslides, floods, or heavy rainstorms, and to issue early warnings or alarms in a timely manner.

[0070] S9: Based on Brillouin Optical Time Domain Reflectometry (BOTDR), this distributed fiber optic deformation detection technology has the advantages of single-ended input, long measurement distance, measurable breakpoints, and fully distributed detection. It can be effectively applied to ground and seabed deformation, structural health monitoring of buildings and large-scale foundation engineering, and monitoring of the structural safety of three-dimensional columnar objects such as pipelines.

[0071] S10: The BOTDR-based deformation detector combines coherent detection and microwave heterodyne sweep frequency method to detect Brillouin scattering signals. It utilizes the high-speed computing advantage of FPGA to achieve Brillouin scattering signal noise reduction and Brillouin gain spectrum demodulation, thereby improving the real-time performance of deformation detection or monitoring.

[0072] In some optional embodiments, prior to step S1, the method further includes:

[0073] Step S0: Cover and fix several deformation measurement or monitoring armored optical cables 5 to the monitoring target;

[0074] When measuring or monitoring ground deformation, according to the design of the ground deformation measurement or monitoring network, a shallow trench is dug along the two-dimensional or three-dimensional survey line on the ground, and the armored optical cable 5 for deformation measurement or monitoring is laid to the bottom of the trench and then fixed below the ground surface with cement.

[0075] When measuring or monitoring seabed deformation, based on the design of the seabed deformation measurement or monitoring network, shallow trenches are excavated along the two-dimensional or three-dimensional survey lines on the seabed, and the armored optical cable 5 for deformation measurement or monitoring is laid and buried at the bottom of the trench.

[0076] When measuring or monitoring the deformation of a three-dimensional building, the armored optical cable 5 for deformation measurement or monitoring needs to be tightly and securely fixed to the outer surface of the three-dimensional building where deformation measurement or monitoring is required, using optical cable fixing clips, fixing strips, or fixing cement.

[0077] When measuring or monitoring the deformation of a cylindrical three-dimensional column, the deformation measurement or monitoring armored optical cable 5 needs to be tightly wound and fixed to the outer surface of the three-dimensional column in a spiral shape.

[0078] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A deformation monitoring system based on distributed optical fiber or arrayed grating optical fiber, characterized in that, The instrument includes a composite modulation and demodulation instrument (4) with a distributed fiber deformation sensing port, and several deformation measurement or monitoring armored optical cables (5) uniformly covered and fixed on the measurement or monitoring target. The deformation measurement or monitoring armored optical cable (5) includes a distributed deformation sensing fiber or an array deformation sensing grating fiber for transmitting deformation sensing signals to the composite modulation and demodulation instrument (4) in real time. The distributed fiber deformation sensing port of the composite modulation and demodulation instrument (4) is connected to the distributed deformation sensing fiber or the array deformation sensing grating fiber of the deformation measurement or monitoring armored optical cable (5). The composite modulation and demodulation instrument (4) has distributed optical fiber temperature sensing ports. The deformation measurement or monitoring armored optical cable (5) includes two multimode optical fibers (53) for measuring the temperature change along its line. The tail ends of the two multimode optical fibers (53) are fused into a U-shaped structure (55). The two distributed optical fiber temperature sensing ports of the composite modulation and demodulation instrument (4) are connected to the two multimode optical fibers (53) of the deformation measurement or monitoring armored optical cable (5). The distributed deformation sensing fiber of the armored optical cable (5) for deformation measurement or monitoring includes a bend-insensitive deformation sensing fiber (51), which is a single-mode fiber or a special deformation-sensitive fiber. The deformation measurement or monitoring armored optical cable (5) also includes a sheath (52) for wrapping the bending-insensitive deformation sensing optical fiber (51), and a continuous stainless steel tube (54) for wrapping the sheath (52) and the multimode optical fiber (53). The array deformation sensing grating fiber of the armored optical cable (5) for deformation measurement or monitoring includes a cladding (20), a core (21), a high-density array grating (22) inscribed on the core (21), and a multi-core grating (23); wherein the inscription density of the high-density array grating (22) is between 1 meter and 10 meters. When the measurement or monitoring target is a two-dimensional or three-dimensional measurement or monitoring target area located on the surface or seabed, a number of deformation measurement or monitoring armored optical cables (5) form a two-dimensional or three-dimensional deformation measurement or monitoring network (1) adapted to the measurement or monitoring target. The two-dimensional or three-dimensional deformation measurement or monitoring network (1) is buried in the two-dimensional or three-dimensional measurement or monitoring target area on the surface or seabed by digging trenches. The shape of the two-dimensional or three-dimensional deformation measurement or monitoring network (1) includes any one of rectangular grid or concentric circle. When the target of measurement or monitoring is a three-dimensional building with different deformation magnitudes and directions, several deformation measurement or monitoring armored optical cables (5) form a three-dimensional building deformation measurement or monitoring network (2). The deformation measurement or monitoring armored optical cables (5) of the three-dimensional building deformation measurement or monitoring network (2) are all fixed parallel to the outer surface of the three-dimensional building along the direction with larger deformation. When the target of measurement or monitoring is a cylindrical three-dimensional column, the deformation measurement or monitoring armored optical cable (5) is tightly wound and fixed in a spiral shape on the outer surface of the three-dimensional column to form a spiral deformation measurement or monitoring network (3).

2. A deformation monitoring method based on distributed optical fiber or arrayed grating optical fiber, applicable to the deformation monitoring system based on distributed optical fiber or arrayed grating optical fiber as described in claim 1, characterized in that, Specifically, the following steps are included: S1: Connect the first end of the distributed deformation sensing fiber or array deformation sensing grating fiber of the deformation measurement or monitoring armored optical cable (5) to the deformation sensing fiber signal input end of the composite modulation and demodulation instrument (4), and connect the first ends of the two multimode fibers (53) of the deformation measurement or monitoring armored optical cable (5) to the temperature sensing dual-ended fiber signal input end of the composite modulation and demodulation instrument (4). S2: Start the composite modulation and demodulation instrument (4) to perform real-time deformation modulation and demodulation on the deformation measurement or monitoring armored optical cable (5) laid on the outer surface of underground or seabed or large foundation structure or pipeline, and at the same time, perform real-time temperature change signal modulation and demodulation on the two multimode optical fibers (53). S3: Load the coordinates of each deformation measurement or monitoring armored optical cable (5) onto a three-dimensional topographic map or three-dimensional stereoscopic map, where: The coordinates of armored optical cables (5) buried on the ground or seabed for deformation measurement or monitoring need to be loaded onto the three-dimensional topographic map of the area covered by the two-dimensional or three-dimensional deformation measurement or monitoring network (1); The coordinates of the armored optical cable (5) fixed to the outer surface of the three-dimensional building for deformation measurement or monitoring need to be loaded onto the three-dimensional solid model of the three-dimensional building structure. The deformation measurement or monitoring armored optical cable (5) is spirally wound and fixed on the outer surface of a three-dimensional columnar object. The coordinates need to be loaded onto the three-dimensional columnar diagram on the outer surface of the three-dimensional columnar object. S4: The deformation data of each deformation measurement or monitoring armored optical cable (5) modulated and demodulated in real time by the composite modulation and demodulation instrument (4) is corrected for temperature drift according to the temperature change along the deformation measurement or monitoring armored optical cable (5), and the temperature drift-corrected deformation data of the deformation measurement or monitoring armored optical cable (5) is input and displayed in real time on the three-dimensional topographic map, three-dimensional stereo map or three-dimensional columnar plot; S5: Perform three-dimensional surface interpolation on the real-time deformation data of the armored optical cable (5) after temperature drift correction for deformation measurement or monitoring, and display the deformation data after three-dimensional surface interpolation on the three-dimensional topographic map, three-dimensional stereo map or three-dimensional columnar diagram in real time with different color marks; S6: To conduct comprehensive analysis of real-time measurement or monitoring data of three-dimensional deformation of the ground and seabed, and to conduct real-time long-term deformation measurement or monitoring of fluid changes in underground or seabed oil and gas reservoirs and the injection and extraction status of oil and gas resources in gas and oil storage facilities, as well as to conduct measurement or monitoring of natural earthquakes, collapses, subsidence or landslides based on real-time long-term deformation measurement or monitoring data of the ground or seabed caused by changes in the geostress field below the ground or seabed, and to issue early warnings or alarms in a timely manner. S7: To conduct real-time long-term measurement or monitoring of the three-dimensional deformation of the outer surface of a three-dimensional building, so as to measure or monitor the potential risk of damage to the three-dimensional building structure caused by geological disasters under the three-dimensional building structure in real time, and to issue early warnings or alarms in a timely manner. S8: To perform real-time long-term measurement or monitoring of the three-dimensional deformation of the outer surface of a cylindrical three-dimensional columnar object, so as to measure or monitor the potential risk of damage to the structure of the three-dimensional columnar object caused by geological disasters under the object in real time, and to issue early warnings or alarms in a timely manner.

3. The deformation monitoring method based on distributed optical fiber or arrayed grating optical fiber according to claim 2, characterized in that, Before step S1, the following is also included: Step S0: Cover and fix several deformation measurement or monitoring armored optical cables (5) to the measurement or monitoring target; When measuring or monitoring the deformation of the ground, according to the design of the ground deformation measurement or monitoring network, a shallow trench is dug along the two-dimensional or three-dimensional survey line of the ground, and the armored optical cable (5) for deformation measurement or monitoring is laid to the bottom of the trench and then fixed below the ground surface with cement. When measuring or monitoring seabed deformation, based on the design of the seabed deformation measurement or monitoring network, shallow trenches are dug along the two-dimensional or three-dimensional survey lines on the seabed, and the armored optical cable (5) for deformation measurement or monitoring is laid and buried at the bottom of the trench. When measuring or monitoring the deformation of a three-dimensional building, it is necessary to use optical cable fixing clips, fixing strips, or fixing cement to firmly fix the armored optical cable (5) for deformation measurement or monitoring to the outer surface of the three-dimensional building that needs to be measured or monitored. When measuring or monitoring the deformation of a cylindrical three-dimensional column, the deformation measurement or monitoring armored optical cable (5) needs to be tightly wound and fixed to the outer surface of the three-dimensional column in a spiral shape.

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