Oil and gas pipelines crossing complex geological regions are often subjected to additional loads induced by soil movement during service, resulting in pipeline deflection and deformation. As critical components of oil and gas pipelines, abnormal bending strain data based on IMU (inertial measurement unit) can be caused by bends, which is considered to affect the accurate assessment of pipeline bending deformation states. The positions and geometric characteristics of bends are aimed to be accurately identified based on pipeline centerline data, providing technical support for pipeline bending strain analysis and safety assessment. Based on the pipeline centerline coordinates obtained from IMU, the cubic spline interpolation method was applied to segmentally fit the eastward, northward, and upward trends of the pipeline. The curvature was calculated to determine the locations and geometric characteristics of the bends. The proposed method was verified using the centerline data and MFL (magnetic flux leakage) results from a 4.4 km long-distance pipeline. The error in bend start and end positioning is controlled within 0.025 m by the proposed bend identification method. For detection sensitivity, small bends that cannot be detected by MFL are identified by the proposed method, and the total number of bends identified is 8.0% higher than that detected by MFL. Regarding detection reliability, a recognition accuracy of 96.4% is achieved by this method among the 137 bends detected by MFL. The positions and angles of bends can be quickly and accurately located by the proposed bend identification method based on pipeline centerline coordinate data. The method is applicable to the identification of both hot and cold bends. The analysis of abnormal pipe bending strain measurements based on inertial measurement units is supported by this method, and technical support is provided for constructing of three-dimensional digital models of aging pipelines.
TANG Yu, HOU Yan-fang, SHU Jie, LIN Dong, TU Sheng-wen.
Bend Identification Techniques Based on Pipeline Centerline Coordinate Date[J].
Science Technology and Engineering, 2026, 26(14): 5956-5966 DOI:10.12404/j.issn.1671-1815.2503170
传统的开挖检测方法仅能针对管道的局部位置,难以对长输管道进行全线安全评价。惯性测量单元(inertial measurement unit, IMU)搭载于管道内检测器,在管内流动介质的推动下沿管道前进,记录管道中心线坐标数据和俯仰角、航向角等姿态信息[7-10]。随着定位算法、对准技术和解算方法的不断发展,管道内检测器的速度与位置信息准确度显著提升,从而能够较为准确地获取中心线经纬度和高程等空间信息[8,11-12]。在此基础上,结合空间坐标转换技术,刻画管道三维空间走势并计算弯曲应变,并开展管道安全评价,可克服传统开挖检测的局限性。其中,精准识别管道弯头是管道安全评价的关键环节,直接影响评价结果的准确性。方威伦等[13]通过IMU数据分析发现,在冻土区管道融沉风险段的识别过程中,管道整体位移引发的弯曲变形、凹陷及弯头等局部变形均会在检测数据中表现为较大的应变信号,进而干扰融沉段识别效果。赵晓明等[14]指出,应排除弯头等超阈值弯曲应变变化点,并单独考虑弯头处管道曲率的计算精度。何仁洋等[15]在进行基于IMU数据的应变解析时同样指出,弯头特征识别是确保管道安全评估精度和可靠性的前提。
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