共查询到18条相似文献，搜索用时 406 毫秒
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采用三维非线性有限单元法对牛牛混凝土面板堆石坝施工期和蓄水期的应力变形进行模拟计算,并结合沈珠江提出的指数型曲线流变模型,采用自行编制的有限元程序对大坝进行了三维流变分析,得到了坝体、面板在各个时期的应力和变形情况,以及堆石流变对坝体应力变形的影响;计算面板和周边缝位移时采用了三维子模型法,根据实际的坝体填筑、蓄水过程,对每一期面板浇筑之前的坝体上游面位移进行修正,并通过在面板与堆石体之间设置三维面-面摩擦接触单元,来有效模拟面板的应力、变形,为该坝的进一步优化设计提供了有益的建议。 相似文献
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高混凝土面板堆石坝流变的三维有限元数值模拟 总被引：4，自引：0，他引：4
采用一种新的能模拟高围压条件的堆石料幂函数流变本构模型,对水布垭面板堆石坝进行了考虑堆石料流变特性的应力-应变仿真分析。结果表明,考虑堆石料流变特性后的坝体变形有明显的增加,坝体应力有所松弛。堆石体的流变特性使得面板的挠度有所增加,面板顺坡向和坝轴向拉应力极值有所增大。对于分期浇筑面板、分期蓄水的高混凝土面板堆石坝,选用合适的流变本构模型正确地模拟堆石体的流变特性,其结果可以为大坝填筑进度及面板分期浇筑时间的确定提供参考,对于正确地预测大坝的应力变形也具有重要意义。 相似文献
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流变变形对高面板堆石坝面板脱空的影响分析 总被引：8，自引：3，他引：5
面板堆石坝尤其是高面板堆石坝的运行实践表明,堆石的流变现象比较显著。采用基于直接约束算法的接触力学分析方法模拟了混凝土面板和堆石体之间的接触关系。考虑堆石体的流变特性,并结合天生桥一级面板堆石坝的现场观测结 果,对高面板堆石坝中的面板脱空问题进行了有限元计算分析,研究了坝体流变变形对面板脱空和垫层亏坡问题的影响。 相似文献
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运用复合材料法模拟土工格栅加筋单元,对格栅加筋堆石坝坝顶堆石进行了数值模拟。计算中,土石料采用非线性弹性模型模拟,并用拟静力法模拟地震动荷载。对无地震和有地震两种情况下的加筋效果及加筋层数和格栅模量对加筋效果的影响进行了分析研究,并对格栅加筋机理加以解释。数值模拟结果表明：格栅加筋有利于增加土石坝坝顶堆石的稳定性和抗震性能,随加筋层数和格栅模量的增加,加筋效果愈加显著。 相似文献
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利用邓肯E-B模型,对洮水水库面板堆石坝在施工期和蓄水期的变形应力进行有限元计算分析,获得了堆石体和面板的变形、应力分布。结果表明,所设计的面板堆石坝变形、应力是合理的。 相似文献
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《岩土力学》2006,27(7):1170-1170
该书系统介绍了作者在国家“九、五”重点科技攻关计划中有关面板坝大型振动台模型试验与动力分析方面的研究成果。内容包括：根据土石料的静、动力特性，探索建立了面板坝振动台模型试验的相似律，探讨了面板坝大型振动台模型试验方法和测试技术。利用具有世界先进水平的大型三向模拟地震振动台进行了大量二维、三维面板坝振动模型试验。模型坝设计中考虑了多项影响因素，研究了各项因素对试验结果的影响。得到了模型坝的动态特性及各项地震反应性状，为改进和验证面板坝地震动力反应分析方法提供了全面系统的基本资料。采用等效线性法对不同模型坝和不同试验方案进行了二维、三维地震动力反应分析，经过与模型试验结果比较分析，验证和改进了面板坝等效线性动力计算方法。 相似文献
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基于搜集的国内多座土石坝堆石料的动力试验成果,研究了堆石料的振动残余变形特性。在整理试验数据过程中,尝试对沈珠江模型进行改进,改进模型充分考虑固结比对堆石料振动残余变形特性的影响,并能更好地拟合试验数据。通过对理想面板堆石坝进行地震动残余变形计算,对比分析了与沈珠江模型、孔宪京改进模型以及凌华改进模型的异同,阐述了本次改进模型的合理性。此外,在统计大量试验数据的基础上,给出了 - 与 - 关系曲线的平均线及上、下包络线,采用该统计曲线对理想面板堆石坝进行了地震残余变形敏感性分析。计算结果表明：参数c4、c5对坝体残余变形影响较大,参数c1、c2影响程度较小;选取均值曲线参数可应用于缺乏动力试验的中小型土石坝抗震设计。 相似文献
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面板堆石坝垂直缝破坏下三维渗流场有限元模拟 总被引：1，自引：0，他引：1
采用改进节点虚流量法求解无压稳定渗流场,并引入无厚度的裂缝模型对破坏的垂直缝渗流行为进行模拟,得到面板堆石坝裂缝渗流问题的有限元分析方法,并编制Fortran程序。以某混凝土面板堆石坝为例,计算了面板单一垂直缝破坏和多条垂直缝破坏条件下的三维渗流场,得到不同条件下渗流场的水头分布、浸润线以及渗漏量,系统分析了面板堆石坝在垂直缝破坏条件下的稳定渗流场规律和特点。结果表明,该方法能对渗流逸出点和浸润线进行准确定位,还能很好地模拟面板垂直缝破坏对坝区渗流场的影响,可以为面板堆石坝的接缝设计提供参考。 相似文献
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Numerical simulation methods are extensively used to analyze the stress and displacement of concrete‐faced rockfill dams (CFRD). The results of these methods are influenced by fuzzy factors, i.e. geometric features, material properties, loads and boundary conditions, which exist widely in the engineering of CFRD as a kind of commonly uncertain factor. To solve this problem, the information entropy theory and the conventional method of structure analysis, namely, finite element method (FEM), were combined in this work. Information entropy, as an effective tool of measuring uncertainty, was used to represent the uncertainty of CFRD. Based on the model that can transform fuzzy information entropy into random information entropy, fuzzy structure can be transformed into equivalent random structure, then mechanical characteristics of CFRD were analyzed by well‐developed stochastic FEM. As an example, one CFRD was chosen to analyze the structure, and the result shows that this method is effective. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Numerical evaluation of soft inter‐slab joint in concrete‐faced rockfill dam with dual mortar finite element method 
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下载免费PDF全文 Recently constructed concrete‐faced rockfill dams (CFRDs) often use soft inter‐slab joints to prevent axial compression‐induced extrusion damage in the concrete face. Due to the complexity of the multibody contact and the lack of information on the actual behavior of soft joints, it is highly challenging to numerically assess the effect of soft joints in CFRDs. In this paper, we present a numerical approach for the three‐dimensional modeling of CFRDs with hard and soft joints. A dual mortar finite element method with Lagrange multiplier is developed to treat the multibody contact in hard joints with impenetrability condition. The soft joint slab‐filler‐slab contact system is modeled using an equivalent contact interface approach, where the soft contact constraints are imposed using a perturbed Lagrange formulation. Through a series of laboratory tests, the mechanical behavior of soft joint is investigated. An extrusion model for the soft joint is presented and implemented in the dual mortar finite element method. The proposed numerical method is applied to the three‐dimensional analysis of Tianshengqiao‐1 CFRD. Despite the complex multibody contact and strong material and geometry nonlinearities in the CFRD, the proposed method is stable and capable of capturing salient characteristics of the CFRD. Numerical results show that in Tianshengqiao‐1, the employment of soft joints can effectively reduce the axial compression stress, thus greatly alleviating the risk of extrusion damage in the concrete face. 相似文献
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采用挤压边墙技术的高面板坝裂缝成因分析 总被引：3，自引：2，他引：1
为加快施工进度,国内很多高面板堆石坝都采用了挤压边墙技术,用上游坡面的挤压边墙代替传统的垫层。挤压边墙的施工特点决定了其与上覆面板之间的结构关系将与传统的面板-垫层有很大差别。虽然目前面板坝的施工技术和施工水平较以前有较大的提高,但少数工程仍然出现了比较严重的面板裂缝,而采用挤压边墙技术的面板坝施工期出现的裂缝分布规律与采用面板-垫层施工方法有明显的不同。面板裂缝的产生与面板施工期的应力变形状态密切相关,目前面板堆石坝计算中采用的整体模型方法对面板的概化较多,得到的面板应力精度较差。根据挤压边墙实际的施工特点,提出采用子模型法分析面板的应力变形,对某面板坝工程裂缝成因的分析结果表明,温降和上游坡面局部高程不平整引起的面板与挤压边墙之间的局部约束过大是导致面板裂缝的主要原因。 相似文献
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This study evaluated the behaviour of a concrete face rockfill dam (CFRD) built on river gravel foundation on the basis of in-situ measurement records and numerical analysis. The monitoring records were obtained from a detailed deformation-monitoring system. A 3D finite element analysis was performed to assess long-term dam behaviour. The behaviour of the CFRD built on river gravel foundation was analysed comprehensively. A discussion of behaviour, especially with relevance to the behaviour of dams built on stiff-foundation, was included. The effect of the river gravel foundation was analysed, and the exact mechanisms were discussed. The relative contribution of various factors on the long-term behaviour of the CFRD was also studied. In-situ measurements were compared with numerical results to discuss the capability of the numerical model to predict the dam behaviour. 相似文献