阅读说明：本技术 海底管道在位状态的检测方法及检测系统 (Detection method and detection system for in-place state of submarine pipeline ) 是由 刘锦昆 冯春健 张先锋 蒋习民 陈同彦 王保计 徐辉 邵怀海 高文 季文峰 王林 于 2019-01-30 设计创作，主要内容包括：本发明公开了一种海底管道在位状态的检测方法及检测系统,其中该检测方法包括：确定需要进行在位状态检测的一段海底管道被测段；沿海底管道被测段水平间隔一测量距离以测取海底管道被测段的数个三维坐标；分别确定各三维坐标在同一水平面以及同一垂直面上的曲率；分别确定各三维坐标在同一水平面以及同一垂直面上的弯曲应变；与依据所获取的海底管道被测段特性参数确定的海底管道被测段的横截面设计允许应变进行比较,判断海底管道被测段的在位状态；本发明可对海底管道在位状态进行检测,且不受挖沟下沉深度不均匀、地基下沉、侧向滑移等因素影响,可为定量评估海底管道健康状态及制定海底管道隐患治理方案提供基础性数据。(The invention discloses a detection method and a detection system for the in-place state of a submarine pipeline, wherein the detection method comprises the following steps: determining a section of a submarine pipeline to be detected, which needs to be subjected to in-situ state detection; horizontally spacing a measuring distance along the measured section of the submarine pipeline to measure a plurality of three-dimensional coordinates of the measured section of the submarine pipeline; respectively determining the curvatures of the three-dimensional coordinates on the same horizontal plane and the same vertical plane; respectively determining the bending strain of each three-dimensional coordinate on the same horizontal plane and the same vertical plane; comparing the strain with the allowable strain of the cross section design of the measured section of the submarine pipeline determined according to the acquired characteristic parameters of the measured section of the submarine pipeline, and judging the in-place state of the measured section of the submarine pipeline; the invention can detect the in-place state of the submarine pipeline, is not influenced by factors such as uneven trenching sinking depth, foundation sinking, lateral sliding and the like, and can provide basic data for quantitatively evaluating the health state of the submarine pipeline and formulating a submarine pipeline hidden danger treatment scheme.)

1. A method for detecting the in-place state of a submarine pipeline is characterized by comprising the following steps:

determining a section of a submarine pipeline to be detected, which needs to be subjected to in-situ state detection;

horizontally spacing a measuring distance along the measured section of the submarine pipeline to measure a plurality of three-dimensional coordinates of the measured section of the submarine pipeline;

respectively determining the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane;

according to the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane, respectively determining the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain of each three-dimensional coordinate on the same vertical plane;

determining the allowable strain of the cross section design of the measured section of the submarine pipeline according to the acquired characteristic parameters of the measured section of the submarine pipeline;

and respectively comparing the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain on the same vertical plane with the cross section design allowable strain of the measured section of the submarine pipeline so as to judge the in-place state of the measured section of the submarine pipeline.

2. The method according to claim 1, wherein the three-dimensional coordinates of the measured section of the submarine pipeline are measured by single-beam or multi-beam measurement.

3. The method for detecting the in-place state of a submarine pipeline according to claim 1, wherein the curvature of each of the three-dimensional coordinates on the same horizontal plane and the curvature on the same vertical plane are determined by cubic spline functions, respectively.

4. The method for detecting the in-place state of a submarine pipeline according to claim 3, wherein the curvature of each of the three-dimensional coordinates in the same horizontal plane is determined by a cubic spline function, and the method comprises:

calculating the coordinate (x) of the ith three-dimensional coordinate on the same horizontal plane_i,y_i) Second derivative M of_H,iWherein i is more than or equal to 1,

the calculation method comprises the following steps:

wherein h is_H,i＝x_i-x_i-1，d_H,i＝6f[x_H,i-1,x_H,i,x_H,i+1]；

Calculating the coordinate (x) of the ith three-dimensional coordinate on the same horizontal plane_i,y_i) First derivative m of_H,iWherein i is more than or equal to 1,

the calculation method comprises the following steps:calculating the curvature kappa of the ith three-dimensional coordinate on the same horizontal plane_H,i，

The calculation method comprises the following steps:

determining the curvature of each three-dimensional coordinate on the same vertical plane through a cubic spline function, wherein the method comprises the following steps:

calculating the coordinates of the ith three-dimensional coordinate on the same vertical plane (L)_i,Z_i) Second derivative M of_V,iWherein L_iThe length of the ith three-dimensional coordinate from the starting point of the measured section of the submarine pipeline, Z_iIs the vertical variation of the ith three-dimensional coordinate relative to the starting point of the measured section of the submarine pipeline, i is more than or equal to 1,

the calculation method comprises the following steps:

wherein h is_v,i＝L_i-L_i-1，

d_v,i＝6f[L_v,i-1,L_v,i,L_v,i+1]；

Calculating the coordinates of the ith three-dimensional coordinate on the same vertical plane (L)_i,Z_i) First derivative m of_v,iWherein i is more than or equal to 1,

the calculation method comprises the following steps:

calculating the curvature kappa of the ith three-dimensional coordinate on the same vertical plane_V,i，

The calculation method comprises the following steps:

5. the method according to claim 4, wherein the bending strains of the three-dimensional coordinates on the same horizontal plane and the bending strains of the three-dimensional coordinates on the same vertical plane are respectively determined by calculating the bending strain of the ith three-dimensional coordinate on the same horizontal plane_H,iThe calculation method comprises the following steps:

calculating the bending strain of the ith three-dimensional coordinate on the same vertical plane_v,iThe calculation method comprises the following steps:in the formula, D is the outer diameter of the measured section of the submarine pipeline.

6. The method for detecting the in-place state of the submarine pipeline according to claim 1, wherein the method for determining the cross-sectional design allowable strain of the measured section of the submarine pipeline according to the acquired characteristic parameters of the measured section of the submarine pipeline comprises the following steps:

whereinIn the formula_dDesigning allowable strain for the cross section of the measured section of the submarine pipeline, wherein the characteristic parameters comprise: gamma rayIs a factor of strain resistance, t₂D is the outer diameter of the measured section of the submarine pipeline, sigma_hFor pipe hoop stress, F_yFor the lowest yield strength of the pipeline, α_hα for the ratio of pipe yield_gwIs the butt weld coefficient.

7. The method for detecting the in-place state of the submarine pipeline according to claim 1, wherein the method for judging the in-place state of the detected section of the submarine pipeline comprises the following steps: when the bending strain of the ith three-dimensional coordinate on the same horizontal plane or the same vertical plane is larger than the allowable strain of the cross section design of the measured section of the submarine pipeline, wherein i is larger than or equal to 1, the pipeline section represented by the ith three-dimensional coordinate is in an unhealthy state, otherwise, the pipeline section represented by the ith three-dimensional coordinate is in a healthy state.

8. A subsea pipeline in-place status detection system, comprising: the device comprises a measuring device, a memory, an input device, a processor and a computer program which is stored on the memory and can run on the processor, wherein the measuring device is electrically connected with the processor and used for measuring a plurality of three-dimensional coordinates of a measured section of the submarine pipeline; the input device is electrically connected with the processor and used for inputting the characteristic parameters of the detected section of the submarine pipeline; wherein the processor implements the following steps when executing the computer program:

respectively determining the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane;

according to the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane, respectively determining the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain of each three-dimensional coordinate on the same vertical plane;

determining the allowable strain of the cross section design of the measured section of the submarine pipeline according to the characteristic parameters of the measured section of the submarine pipeline;

and respectively comparing the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain on the same vertical plane with the cross section design allowable strain of the measured section of the submarine pipeline so as to judge the in-place state of the measured section of the submarine pipeline.

9. The system for detecting the in-place state of a submarine pipeline according to claim 8, wherein the measuring device is used for acquiring a plurality of three-dimensional coordinates of the measured section of the submarine pipeline by single-beam or multi-beam surveying.

10. The system for detecting the in-place state of a submarine pipeline according to claim 8, further comprising an output device for outputting the strain and/or bending strain and/or in-place state of the cross-sectional design of the measured section of the submarine pipeline, wherein the strain and/or bending strain and/or in-place state of the measured section of the submarine pipeline is/are the curvature and/or bending strain of the three-dimensional coordinates of the measured section of the submarine pipeline on the same horizontal plane and the same vertical plane.

Technical Field

The invention relates to the field of submarine pipeline structural engineering, in particular to a submarine pipeline in-place state detection method and system.

Background

After the submarine pipeline is laid on the seabed, the pipeline can be bent and deformed in the vertical direction and the horizontal direction under the influences of seabed fluctuation, trenching sinking unevenness, wave flow action and the like. At present, the prediction of the in-place form of the submarine pipeline is based on the form of the sea bed surface, and the strain prediction of the submarine pipeline is carried out by adopting a finite element method, wherein the finite element method is used for solving the strain state adaptive to the form of the sea bed surface by taking the height fluctuation of the sea bed surface as a constraint boundary condition and utilizing the mechanical corresponding relation among the load, the rigidity and the deformation of the submarine pipeline. However, the finite element method usually requires to know the load or forced displacement and deformation history of the pipeline in advance, and therefore, the finite element method can only be applied to the mechanical state analysis before the submarine pipeline is trenched and buried. When the submarine pipeline is buried, the limited unit method has poor accuracy for measuring the in-place form of the submarine pipeline because the transverse deformation of the submarine pipeline is difficult to consider and the submarine pipeline is influenced by uneven sinking depth of a trench, foundation sinking, lateral sliding and the like.

Disclosure of Invention

The invention provides a method and a system for detecting the in-place state of a submarine pipeline, aiming at the technical problem that the in-place state of the submarine pipeline after trenching and burying of the submarine pipeline can only be predicted and cannot be analyzed in the related art.

In order to achieve the above object, the present technical solution provides a method for detecting an in-place state of a submarine pipeline, comprising the steps of: determining a section of a submarine pipeline to be detected, which needs to be subjected to in-situ state detection; horizontally spacing a measuring distance along the measured section of the submarine pipeline to measure a plurality of three-dimensional coordinates of the measured section of the submarine pipeline; respectively determining the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane; respectively determining the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain of each three-dimensional coordinate on the same vertical plane according to the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane; determining the allowable strain of the cross section design of the measured section of the submarine pipeline according to the acquired characteristic parameters of the measured section of the submarine pipeline; and respectively comparing the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain on the same vertical plane with the cross section design allowable strain of the measured section of the submarine pipeline so as to judge the in-place state of the measured section of the submarine pipeline.

As another implementation of the technical scheme, a plurality of three-dimensional coordinates of the measured section of the submarine pipeline are measured through single-beam or multi-beam measurement.

As another implementation of the present technical solution, the curvatures of the three-dimensional coordinates on the same horizontal plane and the same vertical plane are determined by cubic spline functions, respectively.

As another implementation of the present technical solution, a curvature of each three-dimensional coordinate on the same horizontal plane is determined by a cubic spline function, and the method includes:

calculating the coordinate (x) of the ith three-dimensional coordinate on the same horizontal plane_i,y_i) Second derivative M of_H,iWherein i is more than or equal to 1, and the calculation method comprises the following steps:wherein h is_H,i＝x_i-x_i-1，d_H,i＝6f[x_H,i-1,x_H,i,x_H,i+1]；

Calculating the coordinate (x) of the ith three-dimensional coordinate on the same horizontal plane_i,y_i) First derivative m of_H,iWherein i is more than or equal to 1, and the calculation method comprises the following steps:

calculating the curvature kappa of the ith three-dimensional coordinate on the same horizontal plane_H,i，

The calculation method comprises the following steps:

determining the curvature of each three-dimensional coordinate on the same vertical plane through a cubic spline function, wherein the method comprises the following steps:

calculating the coordinates of the ith three-dimensional coordinate on the same vertical plane (L)_i,Z_i) Second derivative M of_V,iWherein L_iIs the length of the ith three-dimensional coordinate from the starting point of the measured section of the submarine pipeline, Z_iIs the vertical variation of the ith three-dimensional coordinate relative to the starting point of the measured section of the submarine pipeline, i is more than or equal to 1,

the calculation method comprises the following steps:wherein h is_v,i＝L_i-L_i-1，d_v,i＝6f[L_v,i-1,L_v,i,L_v,i+1]；

Calculating the coordinates of the ith three-dimensional coordinate on the same vertical plane (L)_i,Z_i) First derivative m of_v,iWherein i is more than or equal to 1, and the calculation method comprises the following steps:

calculating the curvature kappa of the ith three-dimensional coordinate on the same vertical plane_V,i，

The calculation method comprises the following steps:

as another implementation of the technical scheme, a specific method for respectively determining the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain on the same vertical plane is to calculate the bending strain of the ith three-dimensional coordinate on the same horizontal plane_H,iThe calculation method comprises the following steps:

calculating the bending strain of the ith three-dimensional coordinate on the same vertical plane_v,iThe calculation method comprises the following steps:in the formula, D is the outer diameter of the measured section of the submarine pipeline.

As another implementation of the technical solution, the method for determining the allowable strain of the cross-section design of the measured section of the submarine pipeline according to the acquired characteristic parameters of the measured section of the submarine pipeline comprises the following steps:whereinIn the formula_dDesigning allowable strain for the cross section of the measured section of the submarine pipeline, wherein the characteristic parameters comprise: gamma rayIs a factor of strain resistance, t₂For the wall thickness of the pipeline after corrosion, D is the outer diameter of the measured section of the submarine pipeline, sigma_hFor pipe hoop stress, F_yFor the lowest yield strength of the pipeline, α_hα for the ratio of pipe yield_gwIs the butt weld coefficient.

As another implementation of the technical scheme, the method for judging the in-place state of the detected section of the submarine pipeline comprises the following steps: when the bending strain of the ith three-dimensional coordinate on the same horizontal plane or the same vertical plane is larger than the allowable strain of the cross section design of the measured section of the submarine pipeline, wherein i is larger than or equal to 1, the pipeline section represented by the ith three-dimensional coordinate is in an unhealthy state, otherwise, the pipeline section represented by the ith three-dimensional coordinate is in a healthy state.

In order to achieve the above object, the present technical solution further provides a system for detecting an in-place state of a submarine pipeline, including: the device comprises a measuring device, a memory, an input device, a processor and a computer program which is stored on the memory and can run on the processor, wherein the measuring device is electrically connected with the processor and is used for measuring a plurality of three-dimensional coordinates of a measured section of the submarine pipeline; the input device is electrically connected with the processor and used for inputting the characteristic parameters of the detected section of the submarine pipeline; the processor, when executing the computer program, implements the steps of: respectively determining the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane; respectively determining the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain of each three-dimensional coordinate on the same vertical plane according to the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane; determining the allowable strain of the cross section design of the measured section of the submarine pipeline according to the characteristic parameters of the measured section of the submarine pipeline; and respectively comparing the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain on the same vertical plane with the cross section design allowable strain of the measured section of the submarine pipeline so as to judge the in-place state of the measured section of the submarine pipeline.

As another implementation of the technical scheme, the measuring device acquires a plurality of three-dimensional coordinates of the measured section of the submarine pipeline through single-beam or multi-beam surveying.

The technical scheme also comprises an output device which is used for outputting the curvature and/or bending strain and/or in-place state of the strain and/or the three-dimensional coordinates of the measured section of the submarine pipeline on the same horizontal plane and the same vertical plane according to the cross section design of the measured section of the submarine pipeline.

The detection method and the detection system for the in-place state of the submarine pipeline can detect the in-place state of the laid or buried submarine pipeline in real time, and the detection process and the detection result are not influenced by factors such as uneven trenching sinking depth, foundation sinking, lateral sliding and the like.

Drawings

Fig. 1 is a flow chart of steps of the method for detecting the in-place state of the submarine pipeline according to the present invention.

Fig. 2 is a structural diagram of the device of the detection system for the in-place state of the submarine pipeline according to the invention.

Reference symbols in the drawings indicate:

101 a measuring device; 102 an input device; 103 a processor.

Detailed Description

The following detailed description and technical contents of the present invention are described with reference to the drawings, which are provided for reference and illustration purposes only and are not intended to limit the present invention.

The invention provides a submarine pipeline in-place state detection method based on three-dimensional coordinates of the submarine pipeline in-place state, which is characterized in that bending curvatures of the submarine pipeline on a horizontal plane and a vertical plane are respectively calculated through a cubic spline function, so that bending strains of the submarine pipeline on the horizontal plane and the vertical plane are obtained, and then the strain is allowed to be analyzed by combining with the cross section design of a detected section of the submarine pipeline, so that the deformation condition and the stress strain level of the submarine pipeline are accurately reflected.

As shown in fig. 1, an embodiment of the present invention provides a method for detecting an in-place status of a submarine pipeline, which comprises the following steps:

step S1: determining a section of a submarine pipeline to be detected, which needs to be subjected to in-situ state detection;

step S2: horizontally spacing a measuring distance along the measured section of the submarine pipeline to measure a plurality of three-dimensional coordinates of the measured section of the submarine pipeline, wherein the measuring distances can be unequal or equal;

step S3: respectively determining the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane;

step S4: respectively determining the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain of each three-dimensional coordinate on the same vertical plane according to the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane;

step S5: determining the allowable strain of the cross section design of the measured section of the submarine pipeline according to the acquired characteristic parameters of the measured section of the submarine pipeline; in the present invention, the step of determining the cross-sectional design allowable strain of the measured section of the submarine pipeline according to the characteristic parameters may be performed in any step prior to the step of judging the in-place state of the measured section of the submarine pipeline.

Step S6: and respectively comparing the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain on the same vertical plane with the cross section design allowable strain of the measured section of the submarine pipeline so as to judge the in-place state of the measured section of the submarine pipeline.

The curvature of each three-dimensional coordinate on the same horizontal plane and the same vertical plane is calculated by applying a cubic spline function, and specifically, the curvature of each three-dimensional coordinate on the same horizontal plane is determined by the cubic spline function, and the method comprises the following steps:

calculating the coordinate (x) of the ith three-dimensional coordinate on the same horizontal plane_i,y_i) Second derivative M of_H,iWherein i is more than or equal to 1, and the calculation method comprises the following steps:wherein h is_H,i＝x_i-x_i-1，d_H,i＝6f[x_H,i-1,x_H,i,x_H,i+1]；

Calculating the coordinate (x) of the ith three-dimensional coordinate on the same horizontal plane_i,y_i) First derivative m of_H,iWherein i is more than or equal to 1, and the calculation method comprises the following steps:

calculating the curvature kappa of the ith three-dimensional coordinate on the same horizontal plane_H,iThe calculation method comprises the following steps:

calculating the curvature of each three-dimensional coordinate on the same vertical plane through a cubic spline function, wherein the method comprises the following steps:

calculating the coordinates of the ith three-dimensional coordinate on the same vertical plane (L)_i,Z_i) Second derivative M of_V,iWherein L_iIs the length of the ith three-dimensional coordinate from the starting point of the measured section of the submarine pipeline, Z_iThe vertical variation of the ith three-dimensional coordinate relative to the starting point of the measured section of the submarine pipeline is represented, i is more than or equal to 1, and the calculation method comprises the following steps:wherein h is_v,i＝L_i-L_i-1，d_v,i＝6f[L_v,i-1,L_v,i,L_v,i+1]；

Calculating the coordinates of the ith three-dimensional coordinate on the same vertical plane (L)_i,Z_i) First derivative m of_v,iWherein i is more than or equal to 1, and the calculation method comprises the following steps:

calculating the curvature kappa of the ith three-dimensional coordinate on the same vertical plane_V,iThe calculation method comprises the following steps:

the method for respectively determining the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain on the same vertical plane comprises the following steps: calculating the bending strain of the ith three-dimensional coordinate on the same horizontal plane_H,iThe calculation method comprises the following steps:

calculating the bending strain of the ith three-dimensional coordinate on the same vertical plane_v,iThe calculation method comprises the following steps:in the formula, D is the outer diameter of the measured section of the submarine pipeline.

The method for determining the allowable strain of the cross section design of the measured section of the submarine pipeline according to the characteristic parameters of the measured section of the submarine pipeline is obtained according to a submarine pipeline system (SY/T10037-2010), and comprises the following steps:whereinIn the formula_dDesigning allowable strain for the cross section of the measured section of the submarine pipeline, wherein the characteristic parameters comprise: gamma rayAs a factor of the resistance to strain,t₂for the wall thickness of the pipeline after corrosion, D is the outer diameter of the measured section of the submarine pipeline, sigma_hFor pipe hoop stress, F_yThe lowest yield strength, Delta, of the pipeline_hα for the ratio of pipe yield_gwIs the butt weld coefficient.

The specific method for judging the in-place state of the measured section of the submarine pipeline comprises the following steps: when the bending strain of the ith three-dimensional coordinate on the same horizontal plane or the same vertical plane is larger than the allowable strain of the cross section design of the measured section of the submarine pipeline, wherein i is larger than or equal to 1, the pipeline section represented by the ith three-dimensional coordinate is in an unhealthy state, otherwise, the pipeline section represented by the ith three-dimensional coordinate is in a healthy state.

As shown in fig. 2, according to another embodiment of the present invention, a system for detecting an in-place status of a submarine pipeline includes: a measuring device 101, a memory (not shown), an input device 102, a processor 103, and a computer program stored in the memory and capable of running on the processor 103, wherein the measuring device 101 is electrically connected to the processor 103 for measuring three-dimensional coordinates of a measured section of the submarine pipeline; the input device 102 is electrically connected to the processor 103 for inputting the characteristic parameters of the measured section of the submarine pipeline; the processor 103, when executing the computer program, performs the steps of: respectively determining the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane; respectively determining the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain of each three-dimensional coordinate on the same vertical plane according to the curvature of each three-dimensional coordinate on the same horizontal plane and the curvature of each three-dimensional coordinate on the same vertical plane; determining the allowable strain of the cross section design of the measured section of the submarine pipeline according to the characteristic parameters of the measured section of the submarine pipeline; and respectively comparing the bending strain of each three-dimensional coordinate on the same horizontal plane and the bending strain on the same vertical plane with the cross section design allowable strain of the measured section of the submarine pipeline so as to judge the in-place state of the measured section of the submarine pipeline.

The measuring device 101 of the present invention is selected from measuring devices installed at the bottom of a measuring vehicle (measuring vessel) by horizontally spacing a measuring distance (the measuring vessel travels in the direction of the submarine pipeline at different or the same distance intervals)) Transmitting single or multiple beams for determining a plurality of (i) three-dimensional coordinates (X) of a measured section of a submarine pipeline_i、Y_i、Z_i) The three-dimensional coordinates of the starting point (starting point, i ═ 0) of the measured section of the submarine pipeline can be defined as (0, 0). The invention can also adopt other measuring methods to measure the three-dimensional coordinates of the submarine pipeline, such as a magnetic measuring method, an ultra-low frequency electromagnetic positioning technology, a GPS/INS combined positioning technology and the like.

The input device 102 of the present invention is used to input characteristic parameters for determining the allowable strain of the cross-sectional design of the measured section of the submarine pipeline and the bending strain of the pipeline section, and the input device 102 may be a keyboard, a touch pad or a touch screen, a data input port, etc., which is not limited by the present invention. The characteristic parameters include: gamma rayIs a factor of strain resistance, t₁For the wall thickness of the pipeline after corrosion, D is the outer diameter of the measured section of the submarine pipeline, sigma_hFor pipe hoop stress, F_yFor the lowest yield strength of the pipeline, α_hα for the ratio of pipe yield_gwIs the butt weld coefficient.

The present invention may further include an output device (not shown) to output the curvature and/or bending strain and/or in-situ state of the three-dimensional coordinates of the measured section of the submarine pipeline calculated by the processor 103 on the same horizontal plane and the same vertical plane, and/or the cross-sectional design of the measured section of the submarine pipeline allows strain, and the output device may be a display device, a printing device, a mobile terminal, etc., which is not limited in this respect.

The measured result according to the invention is illustrated by the following data of a section of submarine pipeline in a certain coastal area of China measured by the invention, the specification of the steel pipe of the measured section of the submarine pipeline is 762mm × 17.5.5 mm, the material of the steel pipe is API X60, and the yield strength of the steel is 415MPa, and the measured coordinate of the section of the measured section of the submarine pipeline is as follows:

the curvature and bending strain of the section of pipeline in the measured section of subsea pipeline are given in the following table:

according to the characteristic parameters of the measured section of the submarine pipeline, under the current state, the design allowable strain of the cross section of the measured section of the submarine pipeline is 2.6 per thousand, so that the bending strain of the section of the submarine pipeline in the measured section of the submarine pipeline is within the design allowable range.

The detection method and the detection system for the in-place state of the submarine pipeline can provide important basic data for quantitatively evaluating the health state of the submarine pipeline and for managing the integrity of the submarine pipeline and formulating a hidden danger treatment scheme.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and other equivalent changes made by applying the patent concepts of the present invention should fall within the scope of the present invention.