青龙深“U”形拱坝静、动力分析及承载能力研究

发布时间：2018-02-21 02:32

本文关键词： U形拱坝弹塑性有限元渐进破坏过程极限承载能力地震动响应　出处：《武汉大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着碾压混凝土筑坝技术的不断发展,国内外碾压混凝土拱坝的建设越来越成熟。依据拱坝坝址的地形和地质条件,为了更适于发挥拱的作用,往往选择在左右对称的V形河谷修建双曲拱坝。而"U"形碾压混凝土薄、高拱坝在国内外尚不多见,湖北省青龙拱坝因地形条件的独特,尤为特殊,其岸坡坡角在628m-737m高程处高达60°-87°,两侧山体陡峻,呈狭窄的深"U"形,拱坝厚高比为0.18,是极为典型的"U"形薄拱坝。目前,国内外学者对常规"V"形拱坝的静、动力特性及其破坏机制做了深入的研究,而"U"形薄、高拱坝的静、动力特性及安全度的研究亦为鲜见。基于此,本文首先采用静力有限单元法对青龙"U,"形拱坝进行静力分析,探究出其应力分布规律与常规"V"型拱坝的根本性差异,即在距坝底1/4坝高的下游坝面拱冠处出现较大面积的拉应力区,由此引发对青龙"U"形薄拱坝破坏机制及安全度的探讨。继而采用三维弹塑性有限元方法,基于Drucker-Prager准则,利用强度储备系数法及超载法,分别对青龙拱坝的极限承载能力进行弹塑性有限元分析。运用位移突变法、塑性区贯通及收敛性等破坏判据,探讨其破坏机制,评价其整体安全度,总结了青龙"U"形薄拱坝在极限承载过程中的渐进破坏模式特点,并指出其在极限承载过程中由于应力的自行调整,拉应力减小或消失,满足稳定安全要求。最后,基于地震动力分析的有限单元方法,对青龙"U"形拱坝进行模态分析,了解其固有频率和振型,并在此基础上分别采用振型叠加反应谱法和时间历程法对青龙"U"形拱坝进行动力响应分析,总结其不同于常规"V"形拱坝的动力响应特性,对青龙拱坝的抗震安全评价提供了理论基础,并给出了相应的抗震安全措施。本文的研究成果不仅对实际工程的设计及建设具有实际指导作用,而且对类似工程有相应的借鉴和参考意义。
[Abstract]:With the continuous development of roller compacted concrete, RCC arch dam construction at home and abroad more and more mature. On the basis of arch dam is the terrain and geological conditions to make it more suitable to play the role of arch, often choose the V shaped Valley in a symmetrical building double curvature arch dam. The "U" shaped roller compacted concrete thin, high arch dam at home and abroad it is not rare, Hubei province Qinglong arch dam because of the terrain conditions are unique, in particular, the angle of slope in 628m-737m elevation up to 60 DEG -87 DEG, on both sides of the mountain is steep, narrow and deep "U" shape, arch thickness height ratio is 0.18, is a typical "U" shape thin arch dam. At present, domestic and foreign scholars on the conventional "V" shaped arch of the static, dynamic characteristics and failure mechanism was researched, and the "U" shaped thin, high arch dam static, study on the characteristics and safety of power is also rare. Based on this, this paper first uses static finite element method of Qinglong "U, The shape of arch dam by static analysis, exploring the fundamental difference should force distribution with the conventional "V" type of arch dam, in the dam downstream from dam 1/4 high arch dam larger tensile stress area appears at the crown, resulting in the Qinglong "U" shaped thin arch dam failure mechanism and safety degree. By using three-dimensional elastoplastic finite element method, based on the Drucker-Prager criterion, the strength reserve coefficient method and overload method respectively on ultimate bearing capacity of arch dam Qinglong elastic-plastic finite element analysis. Using the displacement mutation method, plastic zone connection and the convergence criterion, discuss the failure mechanism, evaluation the global safety degree, summarizes the Qinglong "U" shaped thin arch dam in the ultimate progressive failure mode features in the process, and pointed out that in the ultimate process due to the stress of self adjustment, the tensile stress decreases or disappears, meet the safety requirements. Finally, stability, The finite element method of seismic dynamic analysis based on Qinglong "U" shaped arch dam modal analysis, the natural frequency and vibration mode, and on this basis respectively by using the mode superposition response of Qinglong "U" shaped arch dam analysis of dynamic response spectrum method and time history method, the total response of the node is different from the conventional the "V" shape of arch dam, provides a theoretical basis for seismic safety evaluation of Qinglong arch dam, seismic and gives the corresponding security measures. This research not only has practical guidance for the design and construction of practical engineering, and have the corresponding reference for similar projects.

【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV642.4

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