场地震陷对地下管线影响研究
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摘要
地震引起的地层沉陷导致埋地管线破坏的事例有很多,为了保证埋地管线的安全和正常使用,研究场地震陷对埋地管线的影响具有重要意义。本文运用ANSYS有限元分析软件,考虑管-土相互作用,对震陷区埋地管线进行了一系列的数值模拟研究,模拟内容包括三大非线性:几何大变形非线性、材料非线性及接触非线性,并对震陷区埋地管线的反应特点进行了分析。论文主要进行了如下工作:
1.总结了埋地管线的抗震研究的一些成果并介绍了震陷区埋地线反应分析研究现状;阐述了震陷区埋地管线抗震研究的必要性,在此基础上提出了论文的研究目标和方法。
2.分析了已有的各种数值模型的优劣,在此基础上确定了本文研究中采用的模型。其中土体采用D-P实体模型,管线采用线弹性壳模型,管-土相互作用采用接触模型,管土体系采用三维模型。
3.阐述了采用ANSYS有限元分析软件进行震陷区管线数值模拟的基本思路,包括非线性分析在ANSYS中的实现、单元选取、有效计算区域、边界条件确定方法、管土体系模型的确立。对于震陷区的实现论文采用的是对一定区域下土体进行挖空,然后模拟土体自重作用下的反应,这样可以实现土体漏斗状的震陷效果,而且土体的变形是连续的。经过模拟试算,震陷效果符合实际情况。
4.研究了土体材料性质、土体震陷量、震陷区大小、管线埋置深度、不同径厚比及相同径厚比这一系列工况下对管线反应的影响,寻找了管线破坏的敏感因子,得出了一些有益的研究成果:1)震陷区管线的反应因土体性质的差别相应有很大差别;2)土体震陷量越大,管线反应越大,但当震陷量达到一定值时,管线反应变化不大;3)震陷区在一个合适的范围内时,它对管线的破坏影响最大;当震陷区小于或大于这个范围时,对管线的影响都小于这个特定震陷区域范围对管线的影响;4)埋深越浅的管线所产生的附加应力和附加应变越大;5)震陷区对管线的破坏影响随径厚比增大而增大;6)径厚比不变时,震陷区对管线的影响随管线直径减小而增大。
5.对论文工作进行了分析与总结,最后提出下一步工作展望。
论文研究成果对震陷区管线的抗震设计有重要参考价值。
A lot of buried pipelines have been destructed by the stratum subsidence, which is caused by the earthquake. In order to guarantee its’security and normal service, It is significant to study the influence of settlement region to the buried-pipeline.
The buried-pipeline in the settlement region has been simulated by the finite element software ANSYS. Nonlinear analysis is considered, geometric gross distortion nonlinear, material nonlinear and contact nonlinear. The following points are discussed in this thesis:
1. Some seismic research achievements of buried pipeline are summarized and the research status on response analysis of buried pipeline in settlement region is introduced. Based on this idea, the research method and research target is put forward.
2. The advantages and disadvantages of theories on various numerical models are analyzed. Based on the analysis, D-P model is used for soil body, shell model is used for pipeline, contiguity model is used for pipe-soil interaction and three-dimensional models are used for the system which is composed of soil and pipeline.
3. The basic ideas of numerical simulation by the finite element software ANSYS is introduced. The realization of nonlinear in ANSYS、the choose of element type、the effective calculation area、the method of confirming boundary conditions and the establishment of pipe-soil interaction model are included. The settlement region is realized by such method in this research: The soil under a certain area is dug hollow, and the response of soil under self weight is simulated. The funnel-shaped effect of ground settlement which is caused by earthquake is realized, and the deformation of soil is continuous. Though simulation and trial calculation, the effects of ground settlement is in accord with the fact.
4. The response of pipeline is influenced by a series of conditions, which include material properties, amount of seismic subsidence, dimension of settlement area, the depth of pipeline buried, the same and the different diameter-thickness ratio. The effects of a series of model parameters to the response of pipeline are studied, and some meaningful results have been obtained. 1)The different responses of pipeline in settlement region are showed because of different soil property. 2)The more amount of seismic subsidence,the larger response of pipeline is. But when the amount of seismic subsidence is at a certain value, the change of response of pipeline is very little.3)When the dimension of settlement area is at an appropriate range, destruction influence to the pipeline is largest. 4)The more shallow the pipeline buried, the larger the additional stress and additional strain is. 6)The destruction influence of settlement region to the pipeline is increased with the larger diameter-thickness ratio. 6)The destruction influence of settlement region to the pipeline is increased with the smaller diameter, when the diameter-thickness ratio is in the same size.
5. The study is summarized and analyzed, and the research need to be done next is presented.
The important reference value for seismic design of pipeline in settlement region is provided by the research results.
1.总结了埋地管线的抗震研究的一些成果并介绍了震陷区埋地线反应分析研究现状;阐述了震陷区埋地管线抗震研究的必要性,在此基础上提出了论文的研究目标和方法。
2.分析了已有的各种数值模型的优劣,在此基础上确定了本文研究中采用的模型。其中土体采用D-P实体模型,管线采用线弹性壳模型,管-土相互作用采用接触模型,管土体系采用三维模型。
3.阐述了采用ANSYS有限元分析软件进行震陷区管线数值模拟的基本思路,包括非线性分析在ANSYS中的实现、单元选取、有效计算区域、边界条件确定方法、管土体系模型的确立。对于震陷区的实现论文采用的是对一定区域下土体进行挖空,然后模拟土体自重作用下的反应,这样可以实现土体漏斗状的震陷效果,而且土体的变形是连续的。经过模拟试算,震陷效果符合实际情况。
4.研究了土体材料性质、土体震陷量、震陷区大小、管线埋置深度、不同径厚比及相同径厚比这一系列工况下对管线反应的影响,寻找了管线破坏的敏感因子,得出了一些有益的研究成果:1)震陷区管线的反应因土体性质的差别相应有很大差别;2)土体震陷量越大,管线反应越大,但当震陷量达到一定值时,管线反应变化不大;3)震陷区在一个合适的范围内时,它对管线的破坏影响最大;当震陷区小于或大于这个范围时,对管线的影响都小于这个特定震陷区域范围对管线的影响;4)埋深越浅的管线所产生的附加应力和附加应变越大;5)震陷区对管线的破坏影响随径厚比增大而增大;6)径厚比不变时,震陷区对管线的影响随管线直径减小而增大。
5.对论文工作进行了分析与总结,最后提出下一步工作展望。
论文研究成果对震陷区管线的抗震设计有重要参考价值。
A lot of buried pipelines have been destructed by the stratum subsidence, which is caused by the earthquake. In order to guarantee its’security and normal service, It is significant to study the influence of settlement region to the buried-pipeline.
The buried-pipeline in the settlement region has been simulated by the finite element software ANSYS. Nonlinear analysis is considered, geometric gross distortion nonlinear, material nonlinear and contact nonlinear. The following points are discussed in this thesis:
1. Some seismic research achievements of buried pipeline are summarized and the research status on response analysis of buried pipeline in settlement region is introduced. Based on this idea, the research method and research target is put forward.
2. The advantages and disadvantages of theories on various numerical models are analyzed. Based on the analysis, D-P model is used for soil body, shell model is used for pipeline, contiguity model is used for pipe-soil interaction and three-dimensional models are used for the system which is composed of soil and pipeline.
3. The basic ideas of numerical simulation by the finite element software ANSYS is introduced. The realization of nonlinear in ANSYS、the choose of element type、the effective calculation area、the method of confirming boundary conditions and the establishment of pipe-soil interaction model are included. The settlement region is realized by such method in this research: The soil under a certain area is dug hollow, and the response of soil under self weight is simulated. The funnel-shaped effect of ground settlement which is caused by earthquake is realized, and the deformation of soil is continuous. Though simulation and trial calculation, the effects of ground settlement is in accord with the fact.
4. The response of pipeline is influenced by a series of conditions, which include material properties, amount of seismic subsidence, dimension of settlement area, the depth of pipeline buried, the same and the different diameter-thickness ratio. The effects of a series of model parameters to the response of pipeline are studied, and some meaningful results have been obtained. 1)The different responses of pipeline in settlement region are showed because of different soil property. 2)The more amount of seismic subsidence,the larger response of pipeline is. But when the amount of seismic subsidence is at a certain value, the change of response of pipeline is very little.3)When the dimension of settlement area is at an appropriate range, destruction influence to the pipeline is largest. 4)The more shallow the pipeline buried, the larger the additional stress and additional strain is. 6)The destruction influence of settlement region to the pipeline is increased with the larger diameter-thickness ratio. 6)The destruction influence of settlement region to the pipeline is increased with the smaller diameter, when the diameter-thickness ratio is in the same size.
5. The study is summarized and analyzed, and the research need to be done next is presented.
The important reference value for seismic design of pipeline in settlement region is provided by the research results.
引文
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[2]沈世杰,关于地下管道的抗震问题,1972,5
[3]刘爱文.基于壳模型的埋地管线抗震分析.中国地震局地球物理研究所博士研究生学位论文,1996
[4]宋珺.地震作用下埋地长距离输水管道动力特性研究.太原理工大学硕士研究生学位论文,2005
[5]马正茂,冯启民,高惠瑛.跨断层长输油(气)管道抗震研究与实践.世界地震工程,2002,18(3):24-31
[6]林巧艺.厦门市燃气管道设计与施工中的抗震措施
[7]孙建刚,滕振超,王伟,魏志真.渭惠渠跨越管道地震动响应分析.世界地震工程,2004,20(4):112-118
[8]严定中,余建星,王永功,王亮.基于砂土液化分析的穿越管道抗震可靠性.自然灾害学报,2004,13(5):113-116
[9]郭恩栋,刘红丽,吴伟.长距离输油管线震后功能状态分析.地震工程与工程振动,2005,25(5):165-168
[10]吴少艳,无德军,陈东.地震对市政管道的破坏及管道的抗震处理.地震工程与工程振动,2006,26(3):200-202
[11]代以斌,万江飞,李惟恒,甄剑超.高温热油管道在盾构内的敷设方式.2006,17(6):30-31
[12]赵林,冯启民.埋地管线有限元建模方法研究.地震工程与工程振动,2001,21(2):53-57
[13]孙刚,蒋录珍,温旭光.跨断层地下管道破坏的数值模拟.山西建筑,2006,32(5):114-115
[14]柳金海主编.不良条件管道工程设计与施工手册.中国物价出版社,1992
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