共查询到20条相似文献,搜索用时 62 毫秒
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基于非线性指数型动接触本构模型,对实际键槽模型进行简化处理。采用的本构模型可以考虑缝面的开合非线性以及横缝键槽的咬合作用。采用点-面接触模型模拟横缝的非线性动接触行为,精细研究了缝面开度、径向位移的变化及其对坝体应力状态的影响,并与平缝结果进行了比较。以一座拟建的混凝土重力拱坝,探讨了横缝及其诱导缝对大坝工作性态的影响,并对横缝键槽的影响进行了综合分析。研究表明,横缝的径向滑移量要远大于开度,当考虑诱导缝时,由于大坝整体性受到削弱,横缝开度变大;考虑键槽效应后,径向滑移效应大幅减小,而法向开度增大,坝踵处的主拉应力以及拱冠梁顶处的拱向拉应力的最大值均变大。 相似文献
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考虑流固耦合效应的辽宁葠窝水库溢流坝段抗震性能分析 总被引:1,自引:0,他引:1
针对辽宁葠窝水库混凝土重力坝抗震问题,采用耦合的拉格朗日-欧拉有限元分析技术,建立了可考虑库水-坝体-基岩动力耦合效应的典型溢流坝段抗震分析数值模型。模型中,采用等效一致粘弹性边界模拟基岩的人工截断边界;采用混凝土弥散裂缝本构模型模拟混凝土的动力特性。根据烈度与地震动之间的关系,确定了水库坝体抗震设计的输入加速度峰值。据此,分析了在不同季节水位变化条件下坝体地震反应的基本特性。研究表明:完好的辽宁葠窝水库混凝土重力坝溢流坝段能满足8度的抗震设防烈度要求。地震下溢流坝段峰值位移出现在胖坝和瘦坝的坝顶迎水面位置处,胖坝的动位移较瘦坝动位移大。胖坝在闸墩与溢流堰交接处出现了拉应力最大值。有库水条件下,瘦坝峰值拉应力出现在坝趾处,无库水条件下,瘦坝最大拉应力出现在溢流堰与闸墩交接处。 相似文献
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为了研究混凝土重力坝在地震动荷载作用下的潜在失效模式,以金安桥碾压混凝土重力坝5号非溢流坝段为例,运用粘弹性边界法和流固耦合法建立了反映重力坝在地震动作用下动力响应特征的坝体-地基-库水抗震分析模型。基于增量动力分析(IDA)法:绘制了以相对位移转角为x轴(损伤指标,DM)和峰值地面加速度为y轴(强度指标,IM)的IDA曲线簇;分析了金安桥大坝在极端荷载作用下的潜在失效模式和其在不同峰值地面加速度下重力坝的损伤破坏过程。结果表明:金安桥大坝在地震动荷载作用下,可能发生功能失效的地方多出现在坝体折坡处、碾压分区交界处、坝踵与坝基交界处、廊道顶等应力集中处。因此,加强对这些区域的抗震防护有利于提高大坝整体的抗震水平。 相似文献
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Adrian E. Scheidegger 《Surveys in Geophysics》1985,7(3):259-271
This brief review demonstrates the significance, on a global scale, of joints as shearing surfaces in the neotectonic stress field. Thus, the principal directions of the neotectonic stress field can be determined by a statistical treatment of joint orientation data. These principal stress directions agree with those postulated from plate tectonic theory in every case, on five continents. 相似文献
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J. C. Jaeger 《Pure and Applied Geophysics》1959,43(1):148-158
Summary The conditions for sliding over artificial joint surfaces have been studied experimentally by cutting rock cylinders at various angles to their axes and studying slip over these surfaces in a triaxial testing apparatus. The types of joint used were: (i) filled with plaster to simulate a soft joint filling, (ii) bare surfaces ground approximately flat, and (iii) natural surfaces across which shear failure had taken place. The results agreed reasonably well with the simple theory for a constant coefficient of friction. Measured coefficients of friction lie in the range 0.5–0.8 and differ by surprisingly little between the various surfaces. The surfaces across which sliding has taken place exhibit interesting slickenside phenomena. Subsidiary failures frequently occur which cut across the joint surfaces. 相似文献
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The paper proposes an alternative method for the earthquake-resistant design of HDC external beam-column joints which is based
on the assumption that the load transferred from the beam and column elements to the joint is predominantly resisted by a
diagonal strut mechanism. The validity of the proposed method is verified experimentally through a comparative study of the
behaviour of seven full-size beam-column joint sub-assemblages—three of them designed in compliance with the current European
Codes and four in accordance with the proposed method—under cyclic loading. The results obtained indicate that, in contrast
with the specimens designed in compliance with current code provisions, those designed so as to comply with the proposed specifications
fully satisfy the code performance requirements. 相似文献
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The behavior of bridge monolithic connections is modeled using a simplified mathematical model that accounts for stress equilibrium,
compatibility of deformations, and the state of bond of longitudinal column bars anchored through the joint panel. In this
regard, a stress gradient factor is introduced, to model the profile of bar stresses along the anchorage. To establish this
factor, two independent mechanisms of stress transfer are considered: a bond mechanism between the anchored bars and the surrounding
concrete and a friction mechanism between the anchored bars and the transverse bars that enclose and restrain the anchorages.
The model is used for calculation of the shear stress–shear strain relationship of all tests found in the international literature
on bridge monolithic connections that showed shear type of failure under simulated seismic loading. Joint strength values
calculated with the proposed model are compared with the experimental results. Based on this comparison the proposed model
is verified for use in interpretation of bridge monolithic connection behavior and design. 相似文献
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Nonlinear aspects of energy dissipation in wood-panel joints 总被引:1,自引:1,他引:0
Sara Casciati 《地震工程与工程振动(英文版)》2007,6(3):259-268
The joints connecting vertical and horizontal elements are the "weak link" in structural systems assembled from wood panels. If they are too weak, local failures may occur, resulting in performance that is significantly below expectations. If they are too resistant, the joints may be unable to dissipate energy during vibrations, thus possibly initiating a fast progressive failure. This paper re-processes and re-elaborates the results of shaking table tests previously carried out by the author and other co-workers. The goal is to assess the feasibility of a joint which is able to dissipate energy during vibration, without degrading the connection performance. 相似文献
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We have found some mistakes in the article by Sara Casciati(2007).The revisions are given below:
1.The last sentence of the first paragraph in p.262 "(Casciati and Faravelli,2007)" should be changed to "(Casciati and Faravelli,1991)". 相似文献
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空间KT型方管加强节点的承载力性能研究 总被引:2,自引:1,他引:1
通过有限元软件ANSYS对空间KT型方管相贯焊接加强节点轴力和弯矩作用下的极限承载力进行了数值模拟研究,采用的加强方式在主管内部设置纵向加劲肋.研究结果表明这种加强方式对于空间KT型节点的单项承载力都有不同程度的提高作用,且提高幅度与几何参数有关. 相似文献