Pipeline structure health monitoring and landslide early warning method and system

Abstract

The application discloses a pipeline structure health monitoring and landslide early warning method and system, and the method comprises the following steps: S1, a centrifugal simulation test platform is built; S2, strain data collected by the centrifugal simulation test platform is acquired; S3, based on plane strain theory, the collected strain data is pretreated, including main strain calculation, azimuth calculation and data denoising; S4, data analysis is carried out on the pretreated data, including coupling law analysis and parameter influence quantitative analysis, and key influence laws are obtained; and S5, based on the key influence laws, early warning criteria are customized, and finally, a two-level early warning system is built, so that the real-time calculation and early warning of the azimuth and the main strain are realized. The application combines the main strain amplitude and the spatial azimuth, makes up for the defects that the traditional method only analyzes the strain size and ignores the direction, and realizes the accurate quantitative analysis of the mechanical response under the three-dimensional multi-axial stress of the pipeline.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, and in particular to a method and system for monitoring the health of pipeline structures and providing early warning of landslides. Background Technology

[0002] 70% of my country's buried oil and gas pipelines are located in mountainous areas of southwest China and other regions prone to geological disasters. Lateral landslides (landslides perpendicular to the pipeline's direction) are a major threat to pipeline safety. Lateral landslides can cause permanent ground deformation, subjecting pipelines to multiaxial composite loads such as tension, compression, shear, and torsion. This can lead to failures such as local buckling, tensile cracking, and ellipticization of the pipeline cross-section. Large-diameter, high-strength (X70, X80) flexible pipelines are particularly susceptible to buckling failure due to their large diameter-to-thickness ratio, seriously affecting the safety of energy transmission.

[0003] The current analysis and testing technologies for buried pipelines in landslide areas face the following core problems, which are also the key challenges that this invention aims to address: 1. Strain analysis is one-sided and ignores dynamic changes in azimuth angle: Traditional methods only monitor the strain amplitude in the axial / circumferential direction of the pipeline, without capturing the changes in the spatial azimuth angle of the principal strain (the angle between the principal strain direction and the longitudinal axis of the pipeline). This makes it impossible to reflect the redistribution characteristics of the three-dimensional multiaxial stress of the pipeline, and it is also difficult to identify the asymmetric strain field caused by bending-shear coupling and neutral axis offset.

[0004] 2. Inaccurate analysis of pipe-soil interaction: Existing two-dimensional models cannot capture the out-of-plane response and multiaxial stress coupling effect of the pipeline, and do not quantitatively analyze the influence of key parameters such as soil dry density and moisture content on pipe-soil interaction. The numerical simulation results are greatly affected by the soil constitutive model and the calibration of pipe-soil interface parameters, resulting in low reliability.

[0005] 3. Lack of a coupled analysis system in experimental methods: Centrifuge physical simulation test is a reliable means to study the interaction between pipe and soil, but existing tests only focus on the deformation and strain of the pipe and have not established a synergistic analysis method of principal strain and azimuth, so they cannot reveal the dynamic coupling law between the two.

[0006] 4. Lack of effective leading indicators for disaster early warning: Traditional monitoring uses strain accumulation as the basis for early warning, but strain accumulation is a result of the later stage of landslides and cannot achieve early warning; existing technologies have not found a temporal relationship between azimuth changes and strain accumulation, and lack early warning indicators that can identify changes in soil-pipe interaction in advance.

[0007] 5. Insufficient applicability of existing design standards: The strain limits of current pipeline design standards (such as ASCE) do not take into account the extreme load characteristics of lateral landslides. Under actual landslide action, the tensile and compressive strains of pipelines are likely to exceed the standard limits, and the design scheme cannot meet the engineering safety requirements. Summary of the Invention

[0008] This invention aims to overcome the shortcomings of existing technologies and provide a method and system for monitoring pipeline structural health and providing early warning of landslides. While existing technologies have attempted to monitor pipeline strain using strain gauges and fiber optic sensors, or to study pipeline deformation through centrifuge tests, none of them have combined the principal strain amplitude with azimuth orientation for synergistic analysis. Nor have they clarified the quantitative impact of soil density and moisture content on the pipeline principal strain-azimuth coupling response through controlled variable experiments, and they have not proposed an early warning criterion based on azimuth changes.

[0009] This invention is achieved using the following technical solution: a method for monitoring the health of pipeline structures and providing early warning of landslides, comprising the following steps: S1: Construct a centrifugation simulation test platform; S2: Acquire strain data collected by the centrifugal simulation test platform; S3: Based on plane strain theory, the collected strain data is preprocessed, including principal strain calculation, azimuth calculation and data denoising; S4: Perform data analysis on the preprocessed data, including coupling law analysis and parameter influence quantitative analysis, to obtain key influence laws; S5: Based on key impact patterns, early warning criteria were customized, and a two-level early warning system was finally established to achieve real-time calculation and early warning of azimuth and main strain.

[0010] Furthermore, the centrifuge simulation test platform is constructed proportionally to the prototype to ensure stress similarity between the test and the prototype. Specifically, it includes: a soil centrifuge unit, a slope soil model, a buried pipeline model, and a sensing and monitoring system.

[0011] Furthermore, the soil centrifuge unit is equipped with a centrifuge to simultaneously collect strain and slope deformation data; The slope soil model is a slope model prepared from soil, and the slope model is prepared by a layered compaction method; The buried pipeline model is simulated using a scaled-down stainless steel pipe and is buried at a pre-set sliding surface on the slope. The sensing and monitoring system is equipped with multiple sensors to collect data on the deformation process of the slope and pipeline.

[0012] Furthermore, step S2 specifically involves: collecting measured strain data of the tensile outer surface and compressive inner surface of multiple monitoring cross sections in three directions (-45°, 0°, and +45°) using a centrifugal simulation test platform; simultaneously, collecting data covering the entire process of the centrifuge loading from 0g to 75g and holding the load for 10 minutes to obtain strain time history data.

[0013] Furthermore, step S3 includes the following sub-steps: S31: Principal strain calculation: Based on plane strain theory, the measured strain data are transformed into normal strain εx, εy and shear strain γxy in the xy plane, and then the principal strain is calculated; S32: Azimuth calculation: The principal strain azimuth α is defined as the maximum principal tensile strain ε x The angle between the direction of the pipe and the longitudinal axis follows the right-hand rule; S33: Data Denoising Processing: Fast Fourier Transform is used to denoise and smooth the time history data of principal strain and azimuth angle to eliminate interference from experimental noise and ensure the validity of the data.

[0014] Furthermore, the formula for calculating the principal strain is: ; Where, ε x For the maximum principal tensile strain, ε y This represents the minimum principal compressive strain.

[0015] Furthermore, the formula for calculating the azimuth angle is: .

[0016] Furthermore, the coupling law analysis includes: Timing characteristic analysis: Extract the initial response time of principal strain and azimuth angle, analyze the temporal relationship between the two, and clarify the order of azimuth angle rotation and strain accumulation; Spatial characteristic analysis: By comparing the asymmetry of principal strain amplitude and azimuth variation on different cross sections of the pipeline and tensile / compression surfaces, the stress redistribution law caused by bending-shear coupling and pipe-soil interaction is clarified. Failure characteristic analysis: Combining pipeline deformation images captured by centrifuge, the correlation between principal strain-azimuth coupling response and failure mode is analyzed to determine the coupling characteristic threshold before failure.

[0017] Furthermore, the quantitative analysis of the parameter influence specifically involves: based on the results of multiple sets of experimental conditions, quantitatively analyzing the influence of soil dry density ρ and moisture content ω on the pipeline principal strain-azimuth coupling response, calculating the principal strain change rate and azimuth fluctuation amplitude corresponding to parameter changes, and thus clarifying the key influence laws.

[0018] Furthermore, step S5 specifically involves: based on the temporal characteristic that azimuth rotation precedes strain accumulation, a azimuth-priority early warning criterion is customized: abnormal azimuth rotation is used as an early warning indicator for buried pipeline landslide disasters, and the principal strain amplitude is used as an indicator of the degree of damage in the later stages of the disaster. The two are combined to construct a two-level early warning system, thereby realizing real-time calculation and early warning of azimuth and principal strain.

[0019] This invention also provides a pipeline structure health monitoring and landslide early warning system, the system comprising: The pipeline monitoring unit includes multiple right-angle strain gauges attached to the tension-bearing outer surface and the compression-bearing inner surface of the pipeline, used to collect strain data in three directions: -45°, 0°, and +45°. The data acquisition and processing unit is electrically connected to the strain flower and is configured to perform principal strain and azimuth angle calculation, fast Fourier transform denoising, and time series feature extraction. The early warning output unit, connected to the data acquisition and processing unit, is configured to output a first-level early warning signal and a second-level early warning signal based on the progressive triggering logic of the cumulative rotation amplitude of the azimuth angle and the strain amplitude.

[0020] The beneficial effects of this invention are as follows: This invention establishes a principal strain-azimuth angle collaborative analysis system for buried pipelines, combining the principal strain amplitude with the spatial azimuth angle. This overcomes the shortcomings of traditional methods that only analyze strain magnitude while ignoring direction, enabling precise quantitative analysis of the mechanical response of pipelines under three-dimensional multiaxial stress. It reveals the core temporal law that azimuth angle rotation precedes strain accumulation, discovers early warning indicators for landslide disasters, and overcomes the lag problem of traditional methods that rely on strain accumulation for early warning. Furthermore, it constructs a 1:75 standardized centrifugal simulation test system that strictly follows the similarity law, ensuring the consistency between experimental data and engineering reality, and providing a reliable experimental method for pipe-soil interaction analysis.

[0021] This invention quantitatively analyzes the influence of soil dry density and moisture content on the mechanical response of pipelines, providing quantitative parameters for soil improvement and burial depth design of pipelines in landslide areas. It clarifies the failure modes of pipelines under different soil conditions and proposes targeted design suggestions: strengthening local reinforcement of pipelines in low-density soil areas, enhancing the overall buckling resistance of pipelines in high-density soil areas, and focusing on soil and water conservation and shear resistance measures in high-moisture-content soil areas, thus compensating for the deficiencies of existing design standards. Based on experimental results, it optimizes the strain design limits for pipelines in landslide areas, providing a more practical basis for engineering design.

[0022] This invention proposes an angle-priority early warning criterion for landslide disasters. Abnormal rotation with an azimuth angle of 20-40° is designated as a Level 1 warning (early stage), and exceeding the limit for principal strain amplitude is designated as a Level 2 warning (late stage), thus constructing a two-level early warning system to achieve early identification of landslide disasters. The collaborative analysis method of this invention can be directly integrated into existing pipeline real-time monitoring systems such as Distributed Fiber Optic Sensing (DFOS). By adding an azimuth angle analysis module, the early warning accuracy and response speed of the monitoring system are improved without large-scale modification of existing monitoring equipment, demonstrating good compatibility.

[0023] The centrifuge simulation test system of this invention adopts a standardized design and can adjust soil parameters, pipeline model parameters and scale ratio according to different engineering scenarios. It is suitable for the side slip and landslide response analysis of buried pipelines with different geological conditions and specifications. The principal strain-azimuth angle co-analysis method is based on plane strain theory and right-angle strain rosette data. The calculation method is simple and easy to implement, and can be extended to the mechanical response analysis of buried pipelines under the action of other geological disasters such as earthquakes and fault activity. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0028] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0029] See Figure 1 A method for monitoring the health of pipeline structures and providing early warning of landslides includes the following steps: S1: Construct a centrifugation simulation test platform; S2: Acquire strain data collected by the centrifugal simulation test platform; S3: Based on plane strain theory, the collected strain data is preprocessed, including principal strain calculation, azimuth calculation and data denoising; S4: Perform data analysis on the preprocessed data, including coupling law analysis and parameter influence quantitative analysis, to obtain key influence laws; S5: Based on key impact patterns, early warning criteria were customized, and a two-level early warning system was finally established to achieve real-time calculation and early warning of azimuth and main strain.

[0030] In this embodiment, the centrifuge simulation test platform is constructed at a scale of 1:75 to ensure the stress similarity between the test and the prototype. It mainly consists of four parts: a soil centrifuge platform, a slope soil model, a buried pipeline model, and a sensor monitoring system. The parameters of each part strictly follow the centrifuge test similarity law (length ratio 1 / 75, acceleration ratio 75, strain / friction angle and other dimensionless parameters are consistent).

[0031] Geotechnical centrifuge platform: A Tianjin University TLJ-100A geotechnical centrifuge was used, with a maximum acceleration of 200g and a test load of 75g. It was equipped with a 96-channel data acquisition system (48 channels for strain measurement, 16 channels for acceleration, 16 channels for voltage, and 16 channels for current) to simultaneously acquire strain and slope deformation data. It should be noted that the centrifuge data acquisition system needed to be calibrated and zeroed before the test to ensure data acquisition accuracy. The centrifuge was loaded at a uniform rate, linearly from 0g to 75g, held at that load for 10 minutes, and data was acquired synchronously throughout the entire process.

[0032] Slope soil model selection: Chengdu Longquanshan red bed weathered silty clay (low plasticity silt ML), with a particle size distribution of 94.68% particles smaller than 0.0075mm, a uniformity coefficient Cu=16.05, and a curvature coefficient Cc=1.01, indicating well-graded silty soil; Model preparation: The slope model dimensions are 600mm (length) × 700mm (width) × 500mm (height), with a slope toe angle of 45° and a preset 45° sliding surface (typical instability mode of red bed clay); It is prepared using a layered compaction method, with a compaction layer thickness of 50mm and a compaction energy of 577kJ / m³. 3 It should be noted that when preparing the soil model, the moisture content was calibrated using a microwave drying method, with the error controlled within ±0.3%. Controlled variable design: Four experimental conditions were set up, changing only the soil dry density ρ and moisture content ω, while keeping other parameters constant, to achieve univariate analysis. The conditions are as follows: Table 1 Operating Conditions

[0033] Deformation monitoring: Marker pins are placed every 5cm on the slope surface, and the displacement of the marker pins is recorded in real time by a high-definition camera (accuracy 0.1mm) built into a centrifuge to track the slope sliding process.

[0034] Buried pipeline model, prototype matching: The prototype is an X80 high-strength steel pipe (outer diameter 1422mm, wall thickness 26mm, diameter-to-thickness ratio 54.69) used in the China-Russia / China-Myanmar oil and gas pipeline. Model design: A scaled-down 304 stainless steel pipe is used for simulation, with an outer diameter of 19mm, a wall thickness of 0.35mm, a diameter-to-thickness ratio of 54.29 (consistent with the prototype), a Poisson's ratio of 0.29, and a yield strength of 210MPa. Fixed support frames are set at both ends of the pipeline to prevent overall displacement of the pipeline during the test without affecting local deformation. Layout: The pipeline is buried at a pre-set sliding surface on the slope, with a burial depth-to-diameter ratio H / D=2.6, and five monitoring cross-sections are symmetrically arranged along the length of the pipeline. The strain rosette of the pipeline model must be tightly bonded to the pipeline surface without air bubbles to avoid strain measurement errors.

[0035] The sensing and monitoring system includes: strain monitoring: right-angle strain gauges (RSRs) are attached to the tensile outer surface (outward slope) and compressive inner surface (inward slope) of the pipeline at five monitoring cross-sections. The strain gauges measure a range of ±20000με with an accuracy of 2.01±1%, collecting strain data in three directions: -45°, 0°, and +45°; deformation monitoring: a high-definition camera built into the centrifuge simultaneously captures the deformation process of the slope and the pipeline with a resolution of 0.1mm; data synchronization: strain and deformation data are synchronously recorded through the centrifuge data acquisition system with consistent timestamps to ensure the accuracy of time-series analysis.

[0036] In this embodiment, step S2 specifically involves: collecting measured strains at three directions (-45°, 0°, and +45°) on the tensile outer surface and compressive inner surface of five monitoring cross sections of the pipeline, denoted as εi(-45°), εi(0°), and εi(45°); and obtaining strain time history data by collecting data covering the entire process of the centrifuge loading from 0g to 75g and holding the load for 10 minutes.

[0037] In this embodiment, the principal strain is calculated as follows: Based on plane strain theory, the strain rosette measured data is converted into normal strains εx and εy and shear strain γxy in the xy plane, and then the principal strains (maximum tensile strain and minimum compressive strain) are calculated. The calculation formula is as follows: Transformation between normal strain and shear strain: ; Principal strain calculation: ; Where εx is the maximum principal tensile strain and εy is the minimum principal compressive strain; calculate the maximum principal tensile strain εmax-o and the minimum principal compressive strain εmin-o on the tensile outer surface of the pipe, and the maximum principal tensile strain εmax-i and the minimum principal compressive strain εmin-i on the compressive inner surface.

[0038] Azimuth calculation: The principal strain azimuth α is defined as the maximum principal tensile strain ε. xThe angle between the direction and the longitudinal axis (0°) of the pipe is calculated using the right-hand rule, as follows: ; The azimuth angle αo of the tensioned outer surface and the azimuth angle αi of the compression inner surface of the pipe are calculated respectively to reflect the spatial rotation characteristics of the principal strain direction.

[0039] Data denoising: Fast Fourier Transform (FFT) is used to denoise and smooth the time history data of principal strain and azimuth, eliminating interference from experimental noise and ensuring the validity of the data.

[0040] In this embodiment, the principal strain-azimuth coupling law analysis mainly includes: Timing characteristic analysis: Extract the initial response time of principal strains (εmax-o, εmin-i) and azimuth angles (αo, αi), analyze their temporal relationship, and clarify the order of azimuth rotation and strain accumulation.

[0041] Spatial characteristic analysis: By comparing the asymmetry of principal strain amplitude and azimuth angle changes on different cross sections of the pipeline and tensile / compressive surfaces, the stress redistribution law caused by bending-shear coupling and pipe-soil interaction is revealed.

[0042] Failure characteristic analysis: Combining the pipeline deformation images captured by centrifuge, the correlation between the principal strain-azimuth coupling response and failure modes such as pipeline buckling and tensile cracking is analyzed to determine the coupling characteristic threshold before failure.

[0043] In this embodiment, the influence of soil parameters is quantitatively analyzed: based on the results of four sets of test conditions, the influence of soil dry density ρ and moisture content ω on the pipeline principal strain-azimuth coupling response is quantitatively analyzed, the principal strain change rate and azimuth fluctuation amplitude corresponding to parameter changes are calculated, and the key influence laws are identified.

[0044] In this embodiment, step S5 specifically involves: based on the temporal characteristic that azimuth rotation precedes strain accumulation, an angle-priority early warning criterion is proposed: abnormal azimuth rotation (20~40°) is used as an early warning indicator for buried pipeline landslide disasters, and the principal strain amplitude is used as an indicator of the degree of damage in the later stage of the disaster. The two are combined to construct a two-level early warning system.

[0045] Furthermore, this invention also provides a pipeline structure health monitoring and landslide early warning system, which includes: a pipeline monitoring unit comprising multiple right-angled strain gauges attached to the tension-bearing outer surface and compression-bearing inner surface of the pipeline for collecting strain data in three directions: -45°, 0°, and +45°; a data acquisition and processing unit electrically connected to the strain gauges and configured to perform principal strain and azimuth angle calculation, fast Fourier transform denoising, and temporal feature extraction; and an early warning output unit connected to the data acquisition and processing unit and configured to output a first-level early warning signal and a second-level early warning signal based on a progressive triggering logic of the cumulative rotation amplitude of the azimuth angle and the strain amplitude.

[0046] Using the centrifugal simulation test system and collaborative analysis method described above, full-process data for four working conditions were obtained. Analysis revealed the core coupling law of principal strain-azimuth angle of buried pipelines under lateral slip and landslide action, which can provide a basis for engineering applications and early warning criteria formulation. 1. No landslide condition (TC): The pipeline only experiences slight settlement deformation, the principal strain amplitude is small and symmetrically distributed, the azimuth angle is stable without obvious rotation, the interaction between the pipe and the soil is in a uniformly constrained state, and the pipeline deformation is controllable.

[0047] 2. Landslide Condition (T-1 / T-2 / T-3): The amplitude of the principal strain in the pipeline increases significantly, and the azimuth angle rotates rapidly from 20 to 40°. Moreover, the azimuth angle rotation always precedes the strain accumulation. This time series characteristic provides a core leading indicator for early warning of landslide disasters.

[0048] 3. Effect on soil dry density: Dry density increased by 14.3% (1.4 → 1.6 g / cm³). 3 The maximum principal tensile strain of the pipeline increased by 2.69%, while the maximum principal compressive strain decreased by 89.39%. The high-density soil enhanced the constraint on the pipeline, and the pipeline deformation manifested as uniform beam-like bending, with reduced local stress concentration.

[0049] 4. Effect of soil moisture content: When the moisture content increases by 9% (11%→20%), the maximum principal tensile strain of the pipeline increases by 9.75% (3.62 times the effect of dry density), while the maximum principal compressive strain decreases by 85.11%. High moisture content softens the soil, reduces the shear resistance at the pipe-soil interface, and causes significant tensile-torsional combined deformation of the pipeline, resulting in high-frequency and large fluctuations in the azimuth angle, and the most unstable pipe-soil interaction.

[0050] 5. Strain limit verification: Under a 75g load, the maximum principal tensile strain of the pipeline under landslide conditions is 0.53-0.64%, and the maximum principal compressive strain is 0.71-0.84%, both exceeding the allowable limits of the ASCE standard (tensile strain 35‰, compressive strain 5.5-6.7‰). The pipeline design strain limit needs to be optimized for lateral landslides.

[0051] 6. Failure Mode Association: Landslides in low-density soils are prone to causing local strain concentration and azimuth fluctuations in pipelines, leading to local buckling; landslides in high-moisture-content soils are prone to causing combined tensile and torsional deformation in pipelines, leading to ellipticization and tensile cracking of the cross-section; landslides in high-density soils are prone to causing overall beam bending of pipelines, leading to overall buckling.

[0052] For the foregoing embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily essential to this application.

[0053] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Modifications and variations made by those skilled in the art without departing from the spirit and scope of the invention should be within the protection scope of the appended claims.

Claims

1. A method for monitoring the health of pipeline structures and providing early warning of landslides, characterized in that, Includes the following steps: S1: Construct a centrifugation simulation test platform; S2: Acquire strain data collected by the centrifugal simulation test platform; S3: Based on plane strain theory, the collected strain data is preprocessed, including principal strain calculation, azimuth calculation and data denoising; S4: Perform data analysis on the preprocessed data, including coupling law analysis and parameter influence quantitative analysis, to obtain key influence laws; S5: Based on key impact patterns, early warning criteria were customized, and a two-level early warning system was finally established to achieve real-time calculation and early warning of azimuth and main strain.

2. The pipeline structure health monitoring and landslide early warning method as described in claim 1, characterized in that, The centrifuge simulation test platform is constructed proportionally to the prototype to ensure stress similarity between the test and the prototype. Specifically, it includes: a soil centrifuge unit, a slope soil model, a buried pipeline model, and a sensing and monitoring system.

3. The pipeline structure health monitoring and landslide early warning method as described in claim 2, characterized in that, The soil centrifuge unit is equipped with a centrifuge to simultaneously collect strain and slope deformation data; The slope soil model is a slope model prepared from soil, and the slope model is prepared by a layered compaction method; The buried pipeline model is simulated using a scaled-down stainless steel pipe and is buried at a pre-set sliding surface on the slope. The sensing and monitoring system is equipped with multiple sensors to collect data on the deformation process of the slope and pipeline.

4. The method for monitoring pipeline structure health and providing early warning of landslides as described in claim 1, characterized in that, Step S2 specifically involves: collecting measured strain data from the tensile outer surface and compressive inner surface of multiple monitoring cross sections in three directions: -45°, 0°, and +45° using a centrifugal simulation test platform; simultaneously, collecting data over the entire process of the centrifuge loading from 0g to 75g and holding the load for 10 minutes to obtain strain time history data.

5. The pipeline structure health monitoring and landslide early warning method as described in claim 1, characterized in that, Step S3 includes the following sub-steps: S31: Principal strain calculation: Based on plane strain theory, the measured strain data are transformed into normal strain εx, εy and shear strain γxy in the xy plane, and then the principal strain is calculated; S32: Azimuth calculation: The principal strain azimuth α is defined as the maximum principal tensile strain ε x The angle between the direction of the pipe and the longitudinal axis follows the right-hand rule; S33: Data Denoising Processing: Fast Fourier Transform is used to denoise and smooth the time history data of principal strain and azimuth angle to eliminate interference from experimental noise and ensure the validity of the data.

6. The pipeline structure health monitoring and landslide early warning method as described in claim 5, characterized in that, The formula for calculating the principal strain is: ； Where, ε x For the maximum principal tensile strain, ε y The minimum principal compressive strain; The formula for calculating azimuth is: 。 7. The pipeline structure health monitoring and landslide early warning method as described in claim 1, characterized in that, The coupling law analysis includes: Timing characteristic analysis: Extract the initial response time of principal strain and azimuth angle, analyze the temporal relationship between the two, and clarify the order of azimuth angle rotation and strain accumulation; Spatial characteristic analysis: By comparing the asymmetry of principal strain amplitude and azimuth variation on different cross sections of the pipeline and tensile / compression surfaces, the stress redistribution law caused by bending-shear coupling and pipe-soil interaction is clarified. Failure characteristic analysis: Combining pipeline deformation images captured by centrifuge, the correlation between principal strain-azimuth coupling response and failure mode is analyzed to determine the coupling characteristic threshold before failure.

8. The method for monitoring pipeline structure health and providing early warning of landslides as described in claim 1, characterized in that, The quantitative analysis of the parameter influences specifically involves: based on the results of multiple sets of experimental conditions, quantitatively analyzing the influence of soil dry density ρ and moisture content ω on the pipeline principal strain-azimuth coupling response, calculating the principal strain change rate and azimuth fluctuation amplitude corresponding to parameter changes, and thus clarifying the key influence patterns.

9. The method for monitoring pipeline structure health and providing early warning of landslides as described in claim 1, characterized in that, Step S5 specifically involves: based on the temporal characteristic that azimuth rotation precedes strain accumulation, a azimuth-priority early warning criterion is customized: abnormal azimuth rotation is used as an early warning indicator for buried pipeline landslide disasters, and the principal strain amplitude is used as an indicator of the degree of damage in the later stages of the disaster. The two are combined to construct a two-level early warning system, thereby realizing real-time calculation and early warning of azimuth and principal strain.

10. A pipeline structure health monitoring and landslide early warning system, characterized in that, include: The pipeline monitoring unit includes multiple right-angle strain gauges attached to the tension-bearing outer surface and the compression-bearing inner surface of the pipeline, used to collect strain data in three directions: -45°, 0°, and +45°. The data acquisition and processing unit is electrically connected to the strain flower and is configured to perform principal strain and azimuth angle calculation, fast Fourier transform denoising, and time series feature extraction. The early warning output unit, connected to the data acquisition and processing unit, is configured to output a first-level early warning signal and a second-level early warning signal based on the progressive triggering logic of the cumulative rotation amplitude of the azimuth angle and the strain amplitude.

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