侵蚀坑作用下承插式埋地管道完整性评价方法

发布时间：2018-09-14 07:40

【摘要】：侵蚀坑的出现具有时间与空间的任意性,使得传统离散式传感器难以对埋地管道附近侵蚀坑的出现与发展进行监测,分布式光纤传感器的优势为此类分布式监测提供了可能。但由于分布式光纤的自身局限,无法对承插式管道的接口处进行有效监测,而有限元分析的反演法则可拟补这一缺陷。根据上述思路,结合管身分布式应变监测数据与管道三维非线性有限元修正模型,建立了侵蚀坑作用下承插式埋地管道完整性评价方法,以及设计了多种管口变形测量装置。主要有以下内容：1)基于ANSYS有限元分析软件,通过应用超弹性单元、土体弹塑性分析、管口与橡胶密封圈的接触分析和管土接触分析等高度非线性分析,以及生死单元技术,建立了侵蚀坑作用下包含承插式柔性接口的埋地管道三维非线性有限元模型。通过计算侵蚀坑的形状与位置、管体内压、管道上方覆土高度等,分析了侵蚀坑作用下埋地管道结构响应与破坏机理。2)当埋地承插式管道遭遇侵蚀坑时,提出了一种基于分布式应变测量光纤监测与三维非线性有限元分析的埋地管道完整性评价的方法。通过进行全尺寸埋地管道在侵蚀坑作用下的监测试验,利用分布式光纤传感器监测管身纵向应变,确定侵蚀坑区域与范围,由埋地管道试验所处环境结合上述建模方法建立有限元模型,并应用监测数据与手动调节法修正承插式埋地管道模型参数,进而由有限元分析获得管口的应力应变和管道剩余承载能力,最后综合利用上述方法对承插式埋地管道的完整性进行综合评价。此方法不但弥补了分布式应变监测技术难以测量管口应力和变形的不足,而且克服了数值模型难以精确模拟埋地管道实际结构状态的局限,为埋地管道的结构状态退化评价和剩余寿命预测提供了科学依据。3)为弥补光纤监测管口的不足,设计了多种光纤测量管口变形装置与监测方法,并通过几组模型试验说明了每种测量装置的测量方式的可行性与测量结果的有效性,为今后分布式光纤对管道的监测提供了一定的使用与设计思路。
[Abstract]:The occurrence of erosion pits is arbitrary in time and space, which makes it difficult for traditional discrete sensors to monitor the occurrence and development of erosion pits near buried pipelines. The advantages of distributed optical fiber sensors make it possible for this kind of distributed monitoring. However, due to the limitations of the distributed optical fiber, it is impossible to monitor the interface of the socket pipe effectively, and the inversion law of finite element analysis can remedy this defect. According to the above ideas, combined with the distributed strain monitoring data of pipe body and the three-dimensional nonlinear finite element correction model of pipeline, a method for evaluating the integrity of buried pipeline under the action of erosion pit is established, and a variety of pipe opening deformation measuring devices are designed. The main contents are as follows: (1) based on ANSYS finite element analysis software, through the application of hyperelastic element, elastoplastic analysis of soil, contact analysis between pipe opening and rubber seal ring and soil-pipe contact analysis, as well as birth and death element technology, A three dimensional nonlinear finite element model of buried pipeline with flexible interface under the action of erosion pit is established. By calculating the shape and position of the erosion pit, the pressure inside the pipe and the height of the overlying soil above the pipe, the structural response and failure mechanism of the buried pipeline under the action of the erosion pit are analyzed. A method for evaluating the integrity of buried pipelines based on distributed strain measurement fiber-optic monitoring and 3D nonlinear finite element analysis is proposed. Through the monitoring test of full-scale buried pipeline under the action of erosion pit, the longitudinal strain of pipe body is monitored by distributed optical fiber sensor, and the area and range of erosion pit are determined. The finite element model is established from the environment of buried pipeline test combined with the above modeling method, and the parameters of embedded buried pipeline model are modified by monitoring data and manual adjustment method. The stress and strain of the pipe mouth and the residual bearing capacity of the pipeline are obtained by the finite element analysis. Finally, the integrality of the embedded pipeline is evaluated synthetically by the above methods. This method not only makes up for the shortage of distributed strain monitoring technology which is difficult to measure the stress and deformation of pipe mouth, but also overcomes the limitation of numerical model which is difficult to accurately simulate the actual structural state of buried pipeline. This paper provides a scientific basis for structural degradation evaluation and residual life prediction of buried pipeline. In order to make up for the shortage of optical fiber monitoring pipe mouth, a variety of optical fiber measuring devices and monitoring methods are designed. The feasibility of each measuring device and the effectiveness of the measurement results are illustrated through several model tests, which provide a certain application and design idea for the monitoring of pipeline by distributed optical fiber in the future.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU991.36;TU992.23

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