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海洋地震频繁且海底土体环境复杂,当地震导致断层土体发生永久变形后,穿越断层的海底埋地管道也将受迫发生变形。为确定变形后的管道能否正常工作,需根据实际工况对其进行应变响应预测。首先通过有限元计算软件ABAQUS建立管道与走滑断层的三维实体模型,模拟管-土间的接触作用并通过等效边界方法修正模型,得到管道局部屈曲破坏形式及应变分布情况。然后,通过调整有限元模型参数对断层交角、管道工作内压、管道径厚比对管道极限塑性应变的影响进行敏感性分析,定性分析不同敏感性因素对穿越走滑断层海底管道应变响应的影响。最后,在数值模拟数据的基础上通过MATLAB软件利用基于遗传算法优化的BP神经网络实现对管道应变响应的精确预测。结果表明:穿越走滑断层管道在发生局部屈曲时,可根据轴向压缩应变突变现象确定管道局部屈曲时对应的断层位移,并且断层交角、管道工作内压和管道径厚比都会对跨断层管道应变响应产生影响。 相似文献
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在考虑管道的材料非线性和几何非线性、管土相互作用的非线性和管道接口非线性的基础上,建立了由管体梁单元、三向土弹簧单元和接口单元组成的埋地非连续管道在断层位移作用下的有限元模型,并以美国密歇根大学Junhee等(2010)所做的跨断层水泥管试验为原型进行了模拟分析。有限元结果给出的水泥管最终变形、接口转角、接口位移与实验结果基本一致,表明本文提出的跨断层埋地非连续管道抗震计算的有限元分析方法具有一定的合理性。有限元结果和试验结果都表明,在逆冲断层作用下,水泥管的破坏主要是因为在管道接口处的轴向压力和弯矩的耦合作用,在断层附近的管道接口承受了较大的转动和压缩位移。本文所提出的分析方法可推广到埋地非连续管道在其它永久地面变形作用下的有限元分析。 相似文献
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碳纤维增强复合材料（CFRP）被广泛应用于工程结构加固领域,以提高结构抵抗变形的能力。基于管道-土体相互作用三维非线性有限元分析方法,研究逆断层作用下埋地油气钢管经外包CFRP加固后的非线性响应规律和破坏模式。基于Hashin失效准则模拟CFRP受力破坏过程,与相关理论公式进行对比验证,并对加固前后逆断层错动连续埋地钢管力学响应进行分析。研究结果表明,CFRP加固钢管可显著提高其抵抗逆断层错动的能力,0°/90°为最佳缠绕角度;管道内压的施加虽抑制了管道轴向应变的增加,但当管道发生局部屈曲后,管道内压会导致管道屈曲集中于应力最大处;管道内压的施加不仅增强了CFRP加固钢管的抗变形能力,还抑制了CFRP加固钢管发生局部屈曲后应变的发展。 相似文献
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埋地管道地震作用下的破坏因素源于地震引起的永久地面变形(PGD),其中管道-土体间相互作用决定土体位移作用到管体的大小。利用离心机试验技术模拟埋地管道在逆断层大位移下的反应特性,重点讨论断层与管道的交角、断层位移大小、管土相互作用、管径和埋深五个参数对管道破坏的影响水平。实验结果表明:上述参数对管道断层作用的反应均有明显影响,其中断层的位移量、管土相互作用、埋深和管径的影响更为显著。本文的研究结果对于管道经过断层区的抗震设计有十分重要的意义。 相似文献
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强烈地震引起的地面永久性大变形是导致埋地供水管线损坏的主要威胁之一。该研究借鉴链式结构的设计思想,基于传统承插式管道接口形式,研发了一种新型管道抗震接口,其可支持一定的轴向伸缩自由变形。当接口变形量达至极限状态时,接口发生自锁现象并能提供较高的抗拉承载力,进而带动相邻管道滑移,以抵消断层错动引起的变形量。针对新型抗震接口开展了轴向力学性能试验,并建立了跨断层下的管线数值模型;同时,数值结果与相关全尺寸试验进行对比验证。该研究以土体压实条件和断层穿越管道位置作为关键变量,研究了加固前后断层错动下承插式管道的力学响应。研究结果表明：提出的抗震接口能够有效地提高管道抵抗地面大变形能力,并且提高接口的轴向抗拉拔能力是提升管道抗断层错动能力的关键;对于松砂土跨断层下的承插式管道接口震损较为严重;断层穿越管道不同的位置会造成不同的接口变形规律;国内规范中管道接口的转角限值过于保守,不利于对跨断层承插式管道安全性能进行合理验算。 相似文献
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跨断层隔震管道分析 总被引：2，自引：2，他引：0
埋地管道在断层错动作用下的内力分析及其抗震措施一直是生命线工程的一个重要问题与研究热点。对地下管道在断层错位下的响应计算,取得的成果较多,比较经典的有Newmark-Hall方法和Kennedy方法。后来又出现基于壳模型的简化方法,如高田至郎提出的简化计算方法等。相对来讲,关于管道抗震措施的研究成果较少。本文提出一种抗震措施,进行了基于壳模型的有限元动力数值模拟,并与4种松到中密场地土条件下的埋地管道断层错位响应进行对比分析。计算结果表明,本方法中三种长度管道的最大轴向拉应变远小于埋地管道的最大轴向拉应变,而且最大轴向压应变亦不大。 相似文献
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穿越逆冲断层的埋地管道非线性反应分析 总被引：2，自引：0，他引：2
穿越逆冲断层的埋地管道在地震作用下,容易发生局部屈曲或整体失稳等形式的破坏,研究逆冲断层作用下的埋地管道地震反应规律,对管道抗震设计及施工等具有重要的意义。本文将埋地管线及周围土体从半无限地球介质中取出,分别以空间薄壳单元和实体单元进行离散,采用非线性接触力学方法模拟管、土之间的滑移、分离及闭合现象;采用线性位移加载模拟断层的错动,考虑了系统初始应力状态的影响,对土体未开裂前的管土相互作用系统进行了拟静力数值分析;分析了位错量、土体刚度、埋设深度、径厚比及跨越角度对埋地管道反应的影响,得出了一些有益的结论。 相似文献
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Simplified design methods for obtaining the maximum strain in pipelines crossing active faults proposed by Newmark, Kennedy and Wang have not considered the section deformation of the pipe. In this study, a new simplified method is developed for obtaining the maximum strain in steel pipes crossing faults considering non‐linearity of material and geometry of pipe section. It is assumed that the pipe will bend near the fault and the geometry of pipe in the longitudinal direction will change according to a bent deformation. On the other hand, the relation between maximum strain and bent angle has been obtained using a beam–shell hybrid FEM for different pipe‐fault conditions. The developed method can be used for calculating the maximum strains for fault‐crossing steel pipes with different angles of crossing both in tension and compression, by considering the deformation of the pipe cross‐section. Copyright © 2001 John Wiley Sons, Ltd. 相似文献
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Permanent earthquake‐induced actions in buried pipelines: Numerical modeling and experimental verification 
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下载免费PDF全文 《地震工程与结构动力学》2018,47(4):966-987
Buried pipelines are often constructed in seismic and other geohazard areas, where severe ground deformations may induce severe strains in the pipeline. Calculation of those strains is essential for assessing pipeline integrity, and therefore, the development of efficient models accounting for soil‐pipe interaction is required. The present paper is aiming at developing efficient tools for calculating ground‐induced deformation on buried pipelines, often triggered by earthquake action, in the form of fault rupture, liquefaction‐induced lateral spreading, soil subsidence, or landslide. Soil‐pipe interaction is investigated by using advanced numerical tools, which employ solid elements for the soil, shell elements for the pipe, and account for soil‐pipe interaction, supported by large‐scale experiments. Soil‐pipe interaction in axial and transverse directions is evaluated first, using results from special‐purpose experiments and finite element simulations. The comparison between experimental and numerical results offers valuable information on key material parameters, necessary for accurate simulation of soil‐pipe interaction. Furthermore, reference is made to relevant provisions of design recommendations. Using the finite element models, calibrated from these experiments, pipeline performance at seismic‐fault crossings is analyzed, emphasizing on soil‐pipe interaction effects in the axial direction. The second part refers to full‐scale experiments, performed on a unique testing device. These experiments are modeled with the finite element tools to verify their efficiency in simulating soil‐pipe response under landslide or strike‐slip fault movement. The large‐scale experimental results compare very well with the numerical predictions, verifying the capability of the finite element models for accurate prediction of pipeline response under permanent earthquake‐induced ground deformations. 相似文献
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The seismic response analysis of buried pipelines at fault crossings is a complex problem requiring nonlinear 3D soil-structure and large deformation analyses. Such analyses are computationally expensive and the results are hard to evaluate. Therefore, a simple numerical model is needed for engineering and design offices to determine the seismic demand of steel pipes at fault crossings. This paper presents a simplified numerical model for buried steel pipes crossing strike-slip faults and oriented perpendicular to the fault. Two pipes with different diameter to thickness (D/t) ratios and steel grades are used in the study. The proposed model permits plastic hinge formations in the pipe due to incrementally applied fault movements, allows determination of the critical length of the pipeline and measure strains developed on the tension and compression sides in the pipe. The model also considers the effect of bending as well as axial strains due to stretching. 相似文献
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A new shell finite element method (FEM) model with an equivalent boundary is presented for estimating the response of a buried
pipeline under large fault movement. The length of affected pipeline under fault movement is usually too long for a shell-mode
calculation because of the limitation of memory and time of computers. In this study, only the pipeline segment near fault
is modeled with plastic shell elements to study the local buckling and the large section deformation in pipe. The material
property of pipe segment far away from the fault is considered as elastic, and nonlinear spring elements at equivalent boundaries
are obtained and applied to two ends of shell model. Compared with the fixed-boundary shell model, the shell model with an
equivalent boundary proposed by the study can remarkably reduce the needed memory and calculating time.
Foundation item: National Natural Sciences Foundation of China (50078049).
Contribution No. 04FE1017, Institute of Geophysics, China Earthquake Administration. 相似文献
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跨断层隔震管道管端与土体相互作用分析 总被引：1，自引：0，他引：1
断层错动是造成埋地管道破坏的重要因素之一,因此,跨断层埋地管道在断层错动下的破坏机制、模型设计与参数分析和管道抗断层措施一直是生命线工程的前沿问题。对跨断层管道内力分析取得的成果较多,比较经典的是Newm ark-Hall方法、Kennedy方法和王汝梁方法,后来又出现基于壳模型的有限元分析方法。现有的管道抗断层措施具有其优点的同时亦有其不足。本文基于壳模型的有限元动力数值模拟,对一种管道跨断层隔震措施进一步研究,考虑管端与土体相互作用计算隔震管段的断层错动响应。计算结果表明拉应变容易在土中的管段传递,相比较而言,压应变不容易在土中的管段传递;最大拉应变降低比较多,最大压应变降低比较少。根据分析结果,对跨断层隔震管段边界条件的选取提出建议。 相似文献
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An equivalent-boundary method for the shell analysis of buried pipelines under fault movement 总被引：2，自引：0，他引：2
Introduction The history of research work on the response of buried pipeline under the fault movement hasbeen about 30 years. Several simplified design methods have been proposed to obtain the maxi-mum stress or strain in pipe. These methods include the theoretical method and the finite elementmethod (FEM). In the theoretical method, the pipe is usually modeled as a cable (Newmark, Hall1975; Kennedy, et al, 1977) or a beam (Wang, Wang, 1995; LIU, ZHANG, 2002). These theoreti-cal me… 相似文献
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This paper deals with seismic wave propagation effects on buried segmented pipelines. A finite element model is developed for estimating the axial pipe strain and relative joint displacement of segmented pipelines. The model accounts for the effects of peak ground strain, shear transfer between soil and pipeline, axial stiffness of the pipeline, joint characteristics of the pipeline, and variability of the joint capacity and stiffness. For engineering applications, simplified analytical equations are developed for estimating the maximum pipe strain and relative joint displacement. The finite element and analytical solutions show that the segmented pipeline is relatively flexible with respect to ground deformation induced by seismic waves and deforms together with the ground. The ground strain within each pipe segmental length is shared by the joint displacement and pipe barrel strain. When the maximum ground strain is higher than 0.001, the pipe barrel strain is relatively small and can be ignored. The relative joint displacement of the segmented pipeline is mainly affected by the variability of the joint pullout capacity and accumulates at locally weak joints. 相似文献