Submarine pipeline stability discrimination method based on seabed scour mechanism analysis

Abstract

The invention discloses a submarine pipeline stability discrimination method based on submarine scour mechanism analysis, and relates to the technical field of submarine facility protection, basic data of a target sea area are obtained, and the basic data comprise geological information of an area where a submarine pipeline is located, hydrological information of a sea area near the pipeline and pipeline information; performing feature analysis on the basic data of the target sea area, and extracting feature data related to water flow scouring, wave scouring and soil particle movement; according to the method, the risk area which is easily influenced by scouring around the pipeline is accurately identified through seabed scouring mechanism analysis, and then key monitoring and early warning are performed on the risk area, so that protection measures are strengthened in a targeted manner, and the influence of scouring on the stability of the pipeline is dynamically evaluated through continuous monitoring and analysis; the problems of pipeline deformation and stress concentration caused by scouring can be found in time, a maintenance strategy is adjusted according to the problems, the pertinence of safety protection is improved, resources can be effectively saved, and the maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of submarine facility protection, and in particular to a submarine pipeline stability determination method based on submarine scouring mechanism analysis. Background Art

[0002] Seabed scour refers to the phenomenon that sediments are moved due to the impact of waves and currents at the point where marine engineering structures contact the seabed. The marine environment is complex and changeable. During the laying and operation of submarine pipelines, they will be affected by many factors, including waves, currents, sediment conditions, etc. The scour phenomenon may cause the sediments around the submarine pipeline to flow away, causing the pipeline to lose support, and then cause safety risks such as pipeline displacement, deformation, and even fracture. Therefore, accurately assessing the impact of submarine scour on pipeline stability is of great significance to ensure the safe operation of the pipeline.

[0003] The seabed scouring mechanism involves multiple interferences such as ocean currents, waves, and sediment particle movements. The interaction between the various movements makes the scouring mechanism more complicated. A single assessment of the impact of scouring movement on the stability of submarine pipelines will lead to a decrease in overall accuracy and even misleading results. Therefore, how to comprehensively consider the interference of multiple movements of the seabed scouring mechanism to accurately judge the stability of the submarine pipeline is a problem we need to solve. To this end, a method for determining the stability of submarine pipelines based on the analysis of the seabed scouring mechanism is proposed. Summary of the invention

[0004] The present invention aims to provide a method for determining the stability of a submarine pipeline based on the analysis of the submarine scour mechanism, so as to solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for determining the stability of a submarine pipeline based on the analysis of the submarine scouring mechanism comprises the following steps: Step 1: Obtain basic data of the target sea area, including geological information of the area where the submarine pipeline is located, hydrological information of the sea area near the pipeline, and pipeline information; Step 2: Perform feature analysis on the basic data of the target sea area, extract feature data related to current scouring, wave scouring and sediment particle movement, and analyze the migration and deposition trends of sediment particles under seabed scouring conditions; Step 3: Based on the analysis results of current scouring, wave scouring and sediment particle movement, the scouring depth of sediments around the submarine pipeline in the target sea area is determined; Step 4: Obtain the stress threshold and deformation threshold of the submarine pipeline based on the pipeline information, and evaluate the abnormal state of the submarine pipeline under the scouring action in combination with the analysis result of the scouring depth, so as to determine the stability of the submarine pipeline; Step 5: Based on the assessment results of submarine pipeline stability, issue risk warning information and formulate targeted protective measures.

[0006] A further improvement of the technical solution of the present invention is that in step 1, the process of acquiring the basic data of the target sea area is: According to the specific location and direction of the submarine pipeline, the sea area where data needs to be collected is delineated, and the turning points, intersections, key nodes in deep water areas, as well as potential risk areas in areas prone to geological disasters and channel intersections are identified as key locations for data collection; Use geological exploration technology (gravity exploration) to obtain geological information on seabed topography, stratigraphic structure, and bottom type, and consult historical geological data to obtain information on geological changes, seismic activity, and fault distribution in the target sea area. Use data from existing ocean observation stations to obtain hydrological information on tides, currents, waves, temperature, and salinity in the sea area near the pipeline; Obtain pipeline design drawings, construction records, and operation logs from pipeline construction and operation units, extract basic information about the pipeline (material, diameter, wall thickness, burial depth, anti-corrosion measures, etc.), and use submarine pipeline inspection equipment based on CT principles to conduct non-destructive inspections on the pipeline to obtain operating status information on pipeline wall thickness, defect distribution, and corrosion degree; The collected geological information, hydrological information and pipeline information are integrated to form a basic sea area data sequence table, which contains the name, source, time, location and numerical information of the data. The integrated data is verified to ensure the accuracy, completeness and consistency of the data, and the relevant data of the basic sea area data sequence table is stored in the database.

[0007] A further improvement of the technical solution of the present invention is that in step 2, the analysis process of sediment particle migration and deposition trend is: Extract the sea area basic data sequence table from the database, and perform feature analysis on the target sea area basic data in the sea area basic data sequence table, and extract the features related to current scouring, wave scouring and sediment particle movement respectively; Based on the hydrological information data in the sea area basic data sequence table, determine the parameters of ocean current speed, direction, wave height, period, and direction to analyze the ocean current scouring characteristics and wave scouring characteristics, and based on the geological information data, determine the parameters of sediment particle size distribution, density, and permeability to analyze the movement characteristics of sediment particles; Extract the parameters of ocean current speed and direction, determine the characteristic values ​​of ocean current scouring force and ocean current power, extract the wave height, period, and direction parameters from the wave data, determine the characteristic values ​​of wave dynamic pressure and shear force, and determine the characteristic values ​​of sediment erosion rate and deposition rate based on the determined sediment particle size distribution, density, and permeability parameters; Based on the characteristic values ​​of ocean current scouring force and ocean current power, combined with sediment characteristics, the ocean current scouring trend index is calculated to analyze the scouring trend of ocean current on sediment particles, and to clarify the migration direction and intensity of sediment particles under the action of ocean current scouring; Based on the characteristic values ​​of wave dynamic pressure and shear force, combined with sediment characteristics, the wave scouring trend index is calculated to analyze the scouring trend of waves on seabed sediments and clarify the migration direction and intensity of sediment particles under wave scouring. The current scouring trend index and the wave scouring trend index are superimposed and analyzed, the interaction between currents and waves is integrated to calculate the sediment particle movement trend index, and the migration and deposition trend of sediment particles under the combined action of currents and waves is comprehensively analyzed.

[0008] A further improvement of the technical solution of the present invention is that the expression of the ocean current scouring tendency index is: ; in, is the ocean current scouring trend index, The value range is between 0 and 1. is the actual ocean current scouring force, which is calculated based on ocean current speed, direction and sediment characteristics. is the benchmark current scouring force, which is a preset reference value used to standardize the current scouring force, V is the actual current speed, is the reference current speed, and Correspondingly, is the median particle size of the sediment, is the baseline sediment particle size, which is a preset reference value used to standardize particle size. is the density of sediment particles, is the water density, when When it is close to 1, it means that the ocean current is strong and the sediment particles are easily washed away. When it is close to 0, it means that the scouring force of the ocean current is weak and the sediment particles are not easily scoured; The expression of the wave scour tendency index is: ; in, is the wave wash trend index, The value range is between 0 and 1. is the actual wave dynamic pressure, calculated based on wave height, period and direction, is the baseline wave dynamic pressure, which is a preset reference value used to standardize the wave dynamic pressure. is the actual wave shear force, which is calculated based on the wave characteristics and sediment characteristics. is the baseline wave shear force, which is a preset reference value used to standardize the shear force. When it is close to 1, it means that the wave scouring force is strong and the sediment particles are easily washed away. When it is close to 0, it means that the wave scouring force is weak and the sediment particles are not easily scoured; The expression of the sediment particle movement trend index is: ; in, is the sediment particle movement trend index, The value range is between 0 and 1. When it is close to 1, it means that the sediment particles are easily washed away by the combined action of currents and waves, and the migration and deposition trends are obvious. When it is close to 0, it means that the sediment particles are not easily washed away by the combined action of currents and waves, and the migration and deposition trends are weak.

[0009] A further improvement of the technical solution of the present invention is that in step 3, the calculation process of the scouring depth of the sediments around the submarine pipeline in the target sea area is: Traverse the hydrological, geological and sediment particle data of the target sea area in the sea area basic data sequence table, analyze the sediment erosion rate around the submarine pipeline based on the current speed, wave height, sediment particle size distribution and sediment characteristics, combined with the interaction of current and waves, and the start-up and transportation process of sediment particles, and determine the sediment deposition rate around the submarine pipeline by combining the current speed, wave characteristics, sediment particle characteristics and seabed topography factors, and analyzing the sedimentation process and deposition conditions of sediment particles; Analyze the migration direction of sediment particles according to the direction and speed of ocean currents and waves and the starting and transport characteristics of sediment particles, and analyze the deposition location of sediment particles according to the sedimentation process and deposition conditions of sediment particles; Select a numerical simulation method that combines computational fluid dynamics (CFD) and discrete element method (DEM). According to the characteristics of the target sea area and the calculation requirements, determine the parameters and boundary conditions of the numerical simulation method. Combined with the combined effects of current scouring, wave scouring and sediment particle movement, as well as the influence of seabed topography and sediment characteristics, build a scouring depth estimation model based on sediment erosion rate and deposition rate. According to the model requirements, the corresponding parameters are input, including current velocity, wave height, sediment particle size distribution, sediment characteristics and seabed topography, and numerical simulation methods are used for calculation to obtain the actual scouring depth of sediments around the submarine pipeline in the target sea area. The calculation results are verified and checked to ensure the accuracy and reliability of the results.

[0010] A further improvement of the technical solution of the present invention is that the calculation expression of the actual scouring depth is: ; in, is the actual scouring depth, is the actual ocean current velocity (m / s), indicating the ocean current velocity around the submarine pipeline. is the benchmark current speed (m / s), which is a preset reference value used to standardize the current speed. H is the actual wave height (m), which indicates the wave height around the submarine pipeline. is the reference wave height (m), is the median particle size of the sediment (m), is the baseline sediment particle size (m), which is a preset reference value used to standardize the sediment particle size. is the density of sediment particles (kg / m³), indicating the density of sediment particles, is the water density (kg / m³), indicating the density of water, S is the seabed topography slope (°), indicating the slope of the seabed topography, is the base seafloor topography slope (°), which is a preset reference value used to standardize the seafloor topography slope.

[0011] A further improvement of the technical solution of the present invention is that in step 4, the evaluation process of the abnormal state of the submarine pipeline under the scouring effect is: Extract relevant data on pipeline materials, pipeline dimensions and design parameters from the collected pipeline information, determine pipeline diameter and reference diameter to analyze stress threshold and deformation threshold of submarine pipeline; According to the pipeline material characteristics and design parameters, combined with relevant standards (API, ASME, etc.), determine the pipeline stress threshold, and then determine the actual pipeline stress and pipeline yield strength threshold; According to the size, material properties and design parameters of the pipeline, combined with the deformation limit of the pipeline during normal use, the deformation threshold of the pipeline is determined, and then the elastic modulus and reference elastic modulus of the pipeline material are determined. The deformation threshold is related to the displacement and strain parameters of the pipeline and is used to evaluate the deformation of the pipeline under scouring. Combined with the scour depth analysis results and relevant pipeline standards, the actual scour depth and scour depth threshold are determined, and based on the pipeline stress threshold and deformation threshold, the abnormal scour state coefficient is comprehensively calculated to evaluate the abnormal state of the submarine pipeline under scour; According to the size of the abnormal scour state coefficient, it is judged whether the submarine pipeline is in an abnormal scour state. If the abnormal scour state coefficient is less than the preset abnormal threshold, it is considered that the pipeline is in an abnormal scour state, and further stability assessment is performed on the pipeline in the abnormal scour state.

[0012] A further improvement of the technical solution of the present invention is that the calculation expression of the abnormal flushing state coefficient is: ; in, is the abnormal scour state coefficient, The value range is between 0 and 1. is the actual scour depth, which is obtained based on the scour depth analysis results. is the scour depth threshold, which is related to the stability of the pipeline, E is the elastic modulus of the pipeline material, is the reference elastic modulus, used to standardize the elastic modulus, is the actual pipeline stress, which is calculated based on the pipeline stress conditions. is the yield strength threshold of the pipeline, R is the pipeline diameter, A reference diameter used to standardize pipe diameters.

[0013] A further improvement of the technical solution of the present invention is that in step 5, the process of issuing risk warning information is as follows: According to the stress threshold and deformation threshold of the submarine pipeline and the scouring depth analysis results, the pipeline material, size and design parameters as well as the stress of the pipeline under scouring are analyzed to comprehensively evaluate the stability of the submarine pipeline; Based on the assessment results, determine the stability status of the submarine pipeline, including stable, relatively stable, and unstable, and identify potential unstable factors and risk points; Based on the assessment results of submarine pipeline stability, risk warnings are issued to relevant personnel. The risk warning information includes the location of risk points, risk level, possible impact range, and recommended preventive measures; Develop targeted protective measures based on the risk warning results of submarine pipeline stability. For unstable factors of scour pit type, adopt riprap, artificial seaweed, and drainage protection measures to increase the support and stability of the pipeline. For potential risks of geological disasters, strengthen geological monitoring and early warning, and take timely response measures. For risks of external force damage, strengthen pipeline inspection and maintenance, and promptly discover and deal with potential safety hazards; Regularly monitor the status of submarine pipelines and collect feedback information to evaluate the effectiveness of protective measures, adjust protection strategies as needed, and record all risk assessments, risk warning information issuance, and protection measures implementation processes to prepare stability assessment reports.

[0014] Due to the adoption of the above technical solution, the present invention has the following technical advances compared with the prior art: The present invention provides a submarine pipeline stability judgment method based on submarine scour mechanism analysis. Through the submarine scour mechanism analysis, the risk area around the pipeline that is susceptible to scour is accurately identified, and then the risk area is monitored and warned, so as to strengthen the protection measures in a targeted manner. Moreover, through continuous monitoring and analysis, the influence of scour on pipeline stability is dynamically evaluated, and pipeline deformation and stress concentration problems caused by scour can be discovered in time, and the maintenance strategy can be adjusted accordingly, which not only improves the pertinence of safety protection, but also effectively saves resources and reduces maintenance costs.

[0015] The present invention provides a submarine pipeline stability judgment method based on submarine scour mechanism analysis. Through the submarine scour mechanism analysis, the stability of the submarine pipeline under the influence of multiple factors such as geology, hydrology, and the pipeline itself can be accurately evaluated, the loss of sediments around the pipeline can be clearly identified, and the risks that may affect the stability of the pipeline can be identified in time, so that corresponding protective measures can be taken to improve the safety and reliability of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0017] Figure 1 is a flow chart of the method of the present invention; Figure 2 is a flow chart for analyzing sediment particle migration and deposition trends of the present invention; Figure 3 This is a flow chart for calculating the scouring depth of sediments around the submarine pipeline in the target sea area of ​​the present invention; Figure 4 The present invention is a flow chart for evaluating the abnormal state of a submarine pipeline under scouring. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Embodiment 1, as Figures 1 to 3 As shown, the present invention provides a method for determining the stability of a submarine pipeline based on the analysis of the submarine scouring mechanism, comprising the following steps: Step 1: Obtain basic data of the target sea area, including geological information of the area where the submarine pipeline is located, hydrological information of the sea area near the pipeline, and pipeline information. According to the specific location and direction of the submarine pipeline, define the scope of the sea area where data needs to be collected, and identify the turning points, intersections, key nodes in deep water areas of the pipeline, as well as potential risk areas in areas prone to geological disasters and channel intersections as key locations for data collection. Use geological exploration technology (gravity exploration) to obtain geological information on seabed topography, stratigraphic structure, and bottom type, and consult historical geological data to obtain information on geological changes, seismic activities, and fault distribution in the target sea area. Use data from existing ocean observation stations to obtain hydrological information on tides, currents, waves, temperature, and salinity in the sea area near the pipeline, and add hydrological monitoring stations at key locations. Stations are set up to conduct real-time monitoring to ensure the timeliness and accuracy of data. Design drawings, construction records, and operation logs of pipelines are obtained from pipeline construction units and operating units. Basic information of pipelines (material, diameter, wall thickness, burial depth, anti-corrosion measures, etc.) is extracted. Submarine pipeline inspection equipment based on CT principle is used to conduct non-destructive inspection of pipelines to obtain operating status information such as pipeline wall thickness, defect distribution, and corrosion degree. The collected geological information, hydrological information, and pipeline information are integrated to form a basic data sequence table for the sea area, where the basic data sequence table for the sea area contains the name, source, time, location, and numerical information of the data. The integrated data is verified to ensure the accuracy, completeness, and consistency of the data. The relevant data of the basic data sequence table for the sea area is stored in the database; Step 2, perform feature analysis on the basic data of the target sea area, extract feature data related to current scouring, wave scouring and sediment particle movement, and analyze the migration and deposition trend of sediment particles under seabed scouring conditions, extract the basic data sequence table of the sea area from the database, and perform feature analysis on the basic data of the target sea area in the basic data sequence table of the sea area, respectively extract features related to current scouring, wave scouring and sediment particle movement, determine the parameters of current speed, direction, wave height, period and direction based on the hydrological information data in the basic data sequence table of the sea area to analyze the current scouring characteristics and wave scouring characteristics, and determine the parameters of sediment particle size distribution, density and permeability based on the geological information data to analyze the sediment particle movement characteristics, extract the parameters of current speed and direction, determine the characteristic values ​​of current scouring force and current power, and extract wave height, Period and direction parameters are used to determine the characteristic values ​​of wave dynamic pressure and shear force. According to the determined sediment particle size distribution, density, and permeability parameters, the characteristic values ​​of sediment erosion rate and deposition rate are determined. Based on the characteristic values ​​of ocean current scouring force and ocean current power, combined with sediment characteristics, the ocean current scouring trend index is calculated to analyze the scouring trend of ocean current on sediment particles, and the migration direction and intensity of sediment particles under the action of ocean current scouring are clarified. Based on the characteristic values ​​of wave dynamic pressure and shear force, combined with sediment characteristics, the wave scouring trend index is calculated to analyze the scouring trend of waves on seabed sediments, and the migration direction and intensity of sediment particles under the action of wave scouring are clarified. The ocean current scouring trend index and the wave scouring trend index are superimposed for analysis, and the interaction between ocean current and waves is comprehensively considered to calculate the sediment particle movement trend index, and the migration and deposition trend of sediment particles under the combined action of ocean current and waves is comprehensively analyzed; Furthermore, the expression of the ocean current scouring trend index is: ; in, is the ocean current scouring trend index, The value range is between 0 and 1. is the actual ocean current scouring force, which is calculated based on ocean current speed, direction and sediment characteristics. is the benchmark current scouring force, which is a preset reference value used to standardize the current scouring force, V is the actual current speed, is the reference current speed, and Correspondingly, is the median particle size of the sediment, is the baseline sediment particle size, which is a preset reference value used to standardize particle size. is the density of sediment particles, is the water density, when When it is close to 1, it means that the ocean current is strong and the sediment particles are easily washed away. When it is close to 0, it means that the scouring force of the ocean current is weak and the sediment particles are not easily scoured. By combining the scouring force of the ocean current with the characteristics of the sediment, the logarithmic function and the radical formula are used to describe the influence of the ocean current velocity and the sediment particle size on the scouring trend, and the scouring trend of the ocean current on the sediment particles is comprehensively evaluated. By comparing the actual value with the benchmark value, the direction and intensity of the migration of sediment particles under the action of the ocean current scouring are quantified, so as to evaluate the influence of the ocean current scouring on the stability of the submarine pipeline in a specific sea area; The expression of wave scour tendency index is: ; in, is the wave wash trend index, The value range is between 0 and 1. is the actual wave dynamic pressure, calculated based on wave height, period and direction, is the baseline wave dynamic pressure, which is a preset reference value used to standardize the wave dynamic pressure. is the actual wave shear force, which is calculated based on the wave characteristics and sediment characteristics. is the baseline wave shear force, which is a preset reference value used to standardize the shear force. When it is close to 1, it means that the wave scouring force is strong and the sediment particles are easily washed away. When it is close to 0, it means that the wave scouring force is weak and the sediment particles are not easily scoured. By combining the wave dynamic pressure and shear force, the logarithmic function and radical formula are used to describe the influence of wave characteristics and sediment particle size on the scouring trend, and the scouring trend of waves on seabed sediments is comprehensively evaluated. By comparing the actual value with the benchmark value, the direction and intensity of sediment particle migration under the action of wave scouring are quantified, so as to evaluate the influence of wave scouring on the stability of submarine pipelines in specific sea areas; The expression of sediment particle movement trend index is: ; in, is the sediment particle movement trend index, The value range is between 0 and 1. It is the ocean current scouring trend index, which reflects the scouring trend of ocean current on sediment particles. is the wave scouring trend index, which reflects the scouring trend of waves on seabed sediments. When it is close to 1, it means that the sediment particles are easily washed away by the combined action of currents and waves, and the migration and deposition trends are obvious. When it is close to 0, it means that the sediment particles are not easily washed away by the combined action of currents and waves, and the migration and deposition trends are weak. By combining the current scouring force with the wave scouring force, the logarithmic function and radical formula are used to describe the influence of the current and wave characteristics and the sediment particle size on the scouring trend, and the migration and deposition trends of the sediment particles under the combined action of currents and waves are comprehensively evaluated. By superimposing the current scouring trend index and the wave scouring trend index, the direction and intensity of the migration of sediment particles under the combined action of currents and waves are quantified, so as to evaluate the influence of current and wave scouring on the stability of submarine pipelines in specific sea areas. Step 3: Based on the analysis results of ocean current scouring, wave scouring and sediment particle movement, the scouring depth of sediments around the submarine pipeline in the target sea area is clarified. The hydrological, geological and sediment particle data of the target sea area in the sea area basic data sequence table are traversed. According to the ocean current velocity, wave height, sediment particle size distribution and sediment characteristics, combined with the interaction of ocean current and waves, and the start-up and transport process of sediment particles, the sediment erosion rate around the submarine pipeline is analyzed. Combined with ocean current velocity, wave characteristics, sediment particle characteristics and seabed topography factors, the sedimentation process and deposition conditions of sediment particles are analyzed to determine the sediment deposition rate around the submarine pipeline. According to the flow direction and velocity of ocean current and waves and the start-up and transport characteristics of sediment particles, the migration direction of sediment particles is analyzed, and according to the sedimentation of sediment particles, the sediment deposition rate around the submarine pipeline is determined. The sedimentation process and deposition conditions are analyzed, the deposition position of sediment particles is analyzed, and a numerical simulation method combining computational fluid dynamics (CFD) and discrete element method (DEM) is selected. According to the characteristics of the target sea area and the calculation requirements, the parameters and boundary conditions of the numerical simulation method are determined. In addition, the combined effects of current scouring, wave scouring and sediment particle movement, as well as the influence of seabed topography and sediment characteristics are combined to build a scouring depth estimation model based on sediment erosion rate and deposition rate. According to the model requirements, the corresponding parameters are input, including current velocity, wave height, sediment particle size distribution, sediment characteristics and seabed topography. The numerical simulation method is used for calculation to obtain the actual scouring depth of sediments around the submarine pipeline in the target sea area, and the calculation results are verified and checked to ensure the accuracy and reliability of the results. Furthermore, the calculation expression of the actual scour depth is: ; in, is the actual scouring depth, which indicates the actual scouring depth of the sediments around the submarine pipeline under specific conditions. is the actual ocean current velocity (m / s), indicating the ocean current velocity around the submarine pipeline. is the benchmark current speed (m / s), which is a preset reference value used to standardize the current speed. H is the actual wave height (m), which indicates the wave height around the submarine pipeline. is the base wave height (m), which is a preset reference value used to standardize wave height. is the median particle size of the sediment (m), is the baseline sediment particle size (m), which is a preset reference value used to standardize the sediment particle size. is the density of sediment particles (kg / m³), indicating the density of sediment particles, is the water density (kg / m³), indicating the density of water, S is the seabed topography slope (°), indicating the slope of the seabed topography, is the base seafloor topography slope (°), which is a preset reference value used to standardize the seafloor topography slope. When the scouring depth increases Increases, indicating that the greater the current speed, the more serious the scouring. When H increases, the scouring depth Increase means the wave height is bigger and the scouring is more serious. When the scouring depth increases decreases, indicating that the larger the sediment particles are, the less likely they are to be washed away. When S increases, the depth of scouring Increased, indicating that the seafloor topography slope is steeper and the scouring is more severe; Step 4: Obtain the stress threshold and deformation threshold of the submarine pipeline based on the pipeline information, and evaluate the abnormal state of the submarine pipeline under the scouring action in combination with the analysis result of the scouring depth, so as to determine the stability of the submarine pipeline; Step 5: Based on the assessment results of submarine pipeline stability, issue risk warning information and formulate targeted protective measures.

[0020] Embodiment 2, as Figure 4 As shown, based on Example 1, the present invention provides a technical solution: Preferably, in step 4, the evaluation process of the abnormal state of the submarine pipeline under the scouring effect is: From the collected pipeline information, relevant data on pipeline materials, pipeline dimensions and design parameters are extracted, and the pipeline diameter and reference diameter are determined to analyze the stress threshold and deformation threshold of the submarine pipeline. The material composition and heat treatment process of the submarine pipeline are understood through the pipeline material. The pipeline material affects the stress threshold of the pipeline. The pipeline dimensions include the diameter and wall thickness of the pipeline, which are used to calculate the deformation threshold of the pipeline. The design pressure and design temperature of the pipeline are obtained through the design parameters to determine the stress condition of the pipeline under normal working conditions. According to the pipeline material characteristics and design parameters, the stress threshold of the pipeline is determined in combination with relevant standards (API, ASME, etc.), and then the actual pipeline stress and the yield strength threshold of the pipeline are determined. The stress threshold is related to the yield strength, tensile strength and sensitivity to hydrogen-induced stress cracking of the pipeline. The stress threshold decreases with the increase of the yield strength and tensile strength of the alloy, and is affected by the ambient temperature. The influence of the stress, hydrogen pressure and purity factors is taken into consideration. According to the size, material properties and design parameters of the pipeline, combined with the deformation limit of the pipeline during normal use, the deformation threshold of the pipeline is determined, and then the elastic modulus and reference elastic modulus of the pipeline material are determined. The deformation threshold is related to the displacement and strain parameters of the pipeline, and is used to evaluate the deformation of the pipeline under the action of scouring. Combined with the scouring depth analysis results and relevant pipeline standards, the actual scouring depth and scouring depth threshold are determined, and based on the pipeline stress threshold and deformation threshold, the abnormal scouring state coefficient is comprehensively calculated to evaluate the abnormal state of the submarine pipeline under the action of scouring. According to the size of the abnormal scouring state coefficient, it is judged whether the submarine pipeline is in an abnormal scouring state. If the abnormal scouring state coefficient is less than the preset abnormal threshold, it is considered that the pipeline is in an abnormal scouring state, and the pipeline in the abnormal scouring state is further evaluated for stability; Furthermore, the calculation expression of the abnormal scour state coefficient is: ; in, is the abnormal scour state coefficient, The value range is between 0 and 1. is the actual scour depth, which is obtained based on the scour depth analysis results. is the scour depth threshold, which is related to the stability of the pipeline, E is the elastic modulus of the pipeline material, is the reference elastic modulus, used to standardize the elastic modulus, is the actual pipeline stress, which is calculated based on the pipeline stress conditions. is the yield strength threshold of the pipeline, R is the pipeline diameter, is the reference diameter used to standardize pipe diameters. When it is close to 1, it means that the scouring depth and stress level of the pipeline are close to the threshold value, and the pipeline is in a normal state. When it is close to 0, it means that the scour depth or stress level of the pipeline far exceeds the threshold, the pipeline is in an abnormal state, and maintenance measures are required; In step 5, the process of issuing risk warning information is as follows: According to the stress threshold and deformation threshold of the submarine pipeline and the results of the scouring depth analysis, the pipeline material, size and design parameters and the stress of the pipeline under scouring are analyzed, and the stability of the submarine pipeline is comprehensively evaluated. According to the evaluation results, the stability state of the submarine pipeline is determined, including stable, relatively stable and unstable, and potential unstable factors and risk points are identified. According to the evaluation results of the submarine pipeline stability, risk warning is carried out and risk warning information is issued to relevant personnel. The risk warning information includes the location of the risk point, the risk level, the possible impact range, and the recommended preventive measures. For the risk warning results of the submarine pipeline stability, targeted protective measures are formulated. Among them, for the unstable factors of the scouring pit type, riprap, artificial seaweed, and sinking drainage protection measures are taken to increase the support and stability of the pipeline. For the potential risks of geological disasters, geological monitoring and early warning are strengthened, and response measures are taken in time. For the risks of external force damage, pipeline inspection and maintenance are strengthened, potential safety hazards are discovered and handled in time, the status of the submarine pipeline is monitored regularly, feedback information is collected to evaluate the effectiveness of protective measures, and protective strategies are adjusted according to needs. All risk assessments, risk warning information issuance and protective measures implementation processes are recorded, and then a stability assessment report is compiled.

[0021] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for determining the stability of a submarine pipeline based on the analysis of the submarine scour mechanism, characterized in that: The following steps are involved: Step 1: Obtain basic data of the target sea area, including geological information of the area where the submarine pipeline is located, hydrological information of the sea area near the pipeline, and pipeline information; Step 2: Perform feature analysis on the basic data of the target sea area, extract feature data related to current scouring, wave scouring and sediment particle movement, and analyze the migration and deposition trends of sediment particles under seabed scouring conditions; Step 3: Based on the analysis results of current scouring, wave scouring and sediment particle movement, the scouring depth of sediments around the submarine pipeline in the target sea area is determined; Step 4: Obtain the stress threshold and deformation threshold of the submarine pipeline based on the pipeline information, and evaluate the abnormal state of the submarine pipeline under the scouring action in combination with the analysis result of the scouring depth, so as to determine the stability of the submarine pipeline; Step 5: Based on the assessment results of submarine pipeline stability, issue risk warning information and formulate targeted protective measures.

2. A method for determining the stability of a submarine pipeline based on the analysis of the submarine scour mechanism according to claim 1, characterized in that: In step 1, the process of acquiring the basic data of the target sea area is as follows: According to the specific location and direction of the submarine pipeline, the sea area where data needs to be collected is delineated, and the turning points, intersections, key nodes in deep water areas, as well as potential risk areas in areas prone to geological disasters and channel intersections are identified as key locations for data collection; Use geological exploration technology to obtain geological information on seabed topography, stratigraphic structure, and bottom type, and consult historical geological data to obtain information on geological changes, seismic activity, and fault distribution in the target sea area. Use data from existing ocean observation stations to obtain hydrological information on tides, currents, waves, temperature, and salinity in the sea area near the pipeline; Obtain pipeline design drawings, construction records, and operation logs from pipeline construction and operation units, extract basic information about the pipeline, and use a submarine pipeline inspection device based on the CT principle to perform non-destructive inspection of the pipeline to obtain operating status information such as pipeline wall thickness, defect distribution, and corrosion degree; The collected geological information, hydrological information and pipeline information are integrated to form a basic sea area data sequence table, where the basic sea area data sequence table contains the name, source, time, location, and numerical information of the data. The integrated data is verified and the relevant data of the basic sea area data sequence table is stored in the database.

3. A method for determining the stability of a submarine pipeline based on the analysis of the submarine scour mechanism according to claim 2, characterized in that: In step 2, the analysis process of sediment particle migration and deposition trend is as follows: Extract the sea area basic data sequence table from the database, and perform feature analysis on the target sea area basic data in the sea area basic data sequence table, and extract the features related to current scouring, wave scouring and sediment particle movement respectively; Based on the hydrological information data in the sea area basic data sequence table, determine the parameters of ocean current speed, direction, wave height, period, and direction to analyze the ocean current scouring characteristics and wave scouring characteristics, and based on the geological information data, determine the parameters of sediment particle size distribution, density, and permeability to analyze the movement characteristics of sediment particles; Extract the parameters of ocean current speed and direction, determine the characteristic values ​​of ocean current scouring force and ocean current power, extract the wave height, period, and direction parameters from the wave data, determine the characteristic values ​​of wave dynamic pressure and shear force, and determine the characteristic values ​​of sediment erosion rate and deposition rate based on the determined sediment particle size distribution, density, and permeability parameters; Based on the characteristic values ​​of ocean current scouring force and ocean current power, combined with sediment characteristics, the ocean current scouring trend index is calculated to analyze the scouring trend of ocean current on sediment particles, and to clarify the migration direction and intensity of sediment particles under the action of ocean current scouring; Based on the characteristic values ​​of wave dynamic pressure and shear force, combined with sediment characteristics, the wave scouring trend index is calculated to analyze the scouring trend of waves on seabed sediments and clarify the migration direction and intensity of sediment particles under wave scouring. The current scouring trend index and the wave scouring trend index are superimposed and analyzed, the interaction between currents and waves is integrated to calculate the sediment particle movement trend index, and the migration and deposition trend of sediment particles under the combined action of currents and waves is comprehensively analyzed.

4. A method for determining the stability of a submarine pipeline based on the analysis of the submarine scour mechanism according to claim 3, characterized in that: The expression of the ocean current scouring tendency index is: ； in, is the ocean current scouring trend index, is the actual ocean current scouring force, is the reference current scouring force, V is the actual current velocity, is the reference current speed, and Correspondingly, is the median particle size of the sediment, is the reference sediment particle size, is the density of sediment particles, is the water density, when When it is close to 1, it means that the ocean current is strong and the sediment particles are easily washed away. When it is close to 0, it means that the scouring force of the ocean current is weak and the sediment particles are not easily scoured; The expression of the wave scour tendency index is: ； in, is the wave wash trend index, is the actual wave dynamic pressure, is the reference wave dynamic pressure, is the actual wave shear force, is the reference wave shear force, when When it is close to 1, it means that the wave scouring force is strong and the sediment particles are easily washed away. When it is close to 0, it means that the wave scouring force is weak and the sediment particles are not easily scoured; The expression of the sediment particle movement trend index is: ； in, is the sediment particle movement trend index, when When it is close to 1, it means that the sediment particles are easily washed away by the combined action of currents and waves, and the migration and deposition trends are obvious. When it is close to 0, it means that the sediment particles are not easily washed away by the combined action of currents and waves, and the migration and deposition trends are weak.

5. A method for determining the stability of a submarine pipeline based on the analysis of the submarine scour mechanism according to claim 4, characterized in that: In step 3, the calculation process of the scouring depth of the sediments around the submarine pipeline in the target sea area is: Traverse the hydrological, geological and sediment particle data of the target sea area in the sea area basic data sequence table, analyze the sediment erosion rate around the submarine pipeline based on the current speed, wave height, sediment particle size distribution and sediment characteristics, combined with the interaction of current and waves, and the start-up and transportation process of sediment particles, and determine the sediment deposition rate around the submarine pipeline by combining the current speed, wave characteristics, sediment particle characteristics and seabed topography factors, and analyzing the sedimentation process and deposition conditions of sediment particles; Analyze the migration direction of sediment particles according to the direction and speed of ocean currents and waves and the starting and transport characteristics of sediment particles, and analyze the deposition location of sediment particles according to the sedimentation process and deposition conditions of sediment particles; Select a numerical simulation method that combines computational fluid dynamics and discrete element method, determine the parameters and boundary conditions of the numerical simulation method according to the characteristics of the target sea area and the calculation requirements, and build a scouring depth estimation model based on sediment erosion rate and deposition rate in combination with the combined effects of current scouring, wave scouring and sediment particle movement, as well as the influence of seabed topography and sediment characteristics; According to the model requirements, the corresponding parameters are input, including current velocity, wave height, sediment particle size distribution, sediment characteristics and seabed topography, and numerical simulation methods are used for calculation to obtain the actual scouring depth of sediments around the submarine pipeline in the target sea area.

6. A method for determining the stability of a submarine pipeline based on the analysis of the submarine scour mechanism according to claim 5, characterized in that: The calculation expression of the actual scouring depth is: ； in, is the actual scouring depth, is the actual ocean current speed, is the reference current speed, H is the actual wave height, is the base wave height, is the median particle size of the sediment, is the reference sediment particle size, is the density of sediment particles, is the water density, S is the seabed topography slope, is the base seafloor topography slope.

7. A method for determining the stability of a submarine pipeline based on the analysis of the submarine scour mechanism according to claim 6, characterized in that: In step 4, the evaluation process of the abnormal state of the submarine pipeline under the scouring effect is as follows: Extract relevant data on pipeline materials, pipeline dimensions and design parameters from the collected pipeline information, determine pipeline diameter and reference diameter to analyze stress threshold and deformation threshold of submarine pipeline; According to the pipeline material characteristics and design parameters, combined with relevant standards, the pipeline stress threshold is determined, and then the actual pipeline stress and pipeline yield strength threshold are determined; According to the size, material properties and design parameters of the pipeline, combined with the deformation limit of the pipeline during normal use, the deformation threshold of the pipeline is determined, and then the elastic modulus and reference elastic modulus of the pipeline material are determined; Combined with the scour depth analysis results and relevant pipeline standards, the actual scour depth and scour depth threshold are determined, and based on the pipeline stress threshold and deformation threshold, the abnormal scour state coefficient is comprehensively calculated to evaluate the abnormal state of the submarine pipeline under scour; According to the size of the abnormal scour state coefficient, it is judged whether the submarine pipeline is in an abnormal scour state. If the abnormal scour state coefficient is less than the preset abnormal threshold, it is considered that the pipeline is in an abnormal scour state, and further stability assessment is performed on the pipeline in the abnormal scour state.

8. The method for determining the stability of a submarine pipeline based on the analysis of the submarine scour mechanism according to claim 7, characterized in that: The calculation expression of the abnormal flushing state coefficient is: ； in, is the abnormal scour state coefficient, The value range is between 0 and 1. is the actual scouring depth, is the scour depth threshold, E is the elastic modulus of the pipeline material, is the reference elastic modulus, is the actual pipe stress, is the yield strength threshold of the pipeline, R is the pipeline diameter, is the reference diameter.

9. A method for determining the stability of a submarine pipeline based on the analysis of the submarine scour mechanism according to claim 8, characterized in that: In step 5, the process of issuing risk warning information is as follows: According to the stress threshold and deformation threshold of the submarine pipeline and the scouring depth analysis results, the pipeline material, size and design parameters as well as the stress of the pipeline under scouring are analyzed to comprehensively evaluate the stability of the submarine pipeline; Based on the assessment results, determine the stability status of the submarine pipeline, including stable, relatively stable, and unstable, and identify potential unstable factors and risk points; Based on the assessment results of submarine pipeline stability, risk warnings are issued to relevant personnel. The risk warning information includes the location of risk points, risk level, impact range, and recommended preventive measures; Formulate targeted protective measures based on the risk warning results of submarine pipeline stability; Regularly monitor the status of submarine pipelines and collect feedback information to evaluate the effectiveness of protective measures, adjust protection strategies as needed, and record all risk assessments, risk warning information issuance, and protection measures implementation processes to prepare stability assessment reports.

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