地基不均匀沉降时埋地管涵纵向力学模型探讨

地基不均匀沉降是影响埋地管涵纵向力学性状的主要因素之一。针对Winkler地基模型的缺陷,采用Pasternak双参数地基模型建立了较为合理的考虑地基差异沉降的埋地管涵纵向力学模型,得到了沉陷区埋地管涵的挠曲线表达式,进而对埋地管涵的纵向力学性状要素进行分析,表明管涵结构的挠度、转角、弯矩、剪力均在差异沉降处有突变,且各要素受不均匀沉降的影响范围有限。     

Elasto-plastic stability of single-layer reticulated shells

Investigation of elasto-plastic stability of reticulated shells has gradually become more and more attractive to researchers. However, the analysis of the elasto-plastic stability is much more complicated than the elastic analysis, because of the involvement of both the geometrical nonlinearity and the material nonlinearity and the interactions of the two. Taking into consideration of material nonlinearity, the elasto-plastic stability behaviour of reticulated shells will be significantly different, which can only be revealed by large amount of geometrically and material nonlinear analysis of the structures. The elasto-plastic stability of seven types of commonly used single-layer reticulated shells (Kiewitt-8, Kiewitt-6, Geodesic, Schwedler Bidirectional, Schwedler Monoclonal, Sunflower, and Radial Rib) was investigated systematically with ANSYS, in which more than 2000 cases of geometrically and material nonlinear analysis were conducted with different initial geometrical imperfections, geometrical, structural and load parameters. Based on the analytical results and via comparison between elastic and elasto-plastic buckling loads, the plasticity influence coefficients were summarized for each type of the reticulated domes. These coefficients can be used to predict accurately the elasto-plastic buckling load in design practice of the reticulated domes, which is an easy way for designers to evaluate stability of the reticulated shells.     

中国建筑设计的导读者:访第五届“梁思成建筑奖”获奖者、北京市建筑设计研究院顾问总建筑师柴裴义

<正>精心耕耘,必有所获。几十年的努力与打拼,也得到了应有的回报。2009年获得梁思成奖,这是建筑业界对我建筑生涯的肯定。面对这些荣誉我诚惶诚恐,既有喜悦,也感到很大的压力。唯有在今后更加努力,带领年轻的建筑师去进一步探索各领域建筑创作之真谛,创作出更优秀的建筑作品回报社会。以上既是北京市建筑设计研究院     

液压捣固机夹实液压缸漏油的原因分析及改进

针对液压捣固机使用过程中经常出现夹实液压缸一快一慢的现象,分析其原因是由于强烈振动引起活塞与活塞杆之间的圆螺母松动,液压油外泄,系统压力降低所致。在不影响活塞强度的情况下,在活塞内圈上车出一定宽度的沟槽,加O形密封圈密封,可有效解决液压油外泄的问题,提高捣固机的作业效率。     

地下热水的水化学资料在判断断层中的应用——以聊城市城区地热田为例

聊城市城区西部临清拗陷区地下热水在水平方向上的水文地球化学特征具有明显的块段性,大致可分为F2断裂以东和F2断裂以西两个块段,这两个块段地下热水在主要离子组分、微量元素和特征系数等方面均有一定差异。本文根据地下热水水化学资料,判断出了F2断裂的大致位置,同时从地下热水水化学特征的块段性差异和地下热水的变质程度两个方面说明了F2断裂的判断依据。     

Vacuum-drain consolidation induced pressure distribution and ground deformation

The method of using a surface or subsurface soil layer as an air-sealing layer to carry out vacuum consolidation is referred to as the vacuum-drain method. A method of determining the vacuum-drain consolidation induced vacuum pressure distribution in the ground has been proposed based on unit cell finite element analysis results. With the calculated vacuum pressure distribution, a method for calculating the settlement–time curve and the lateral displacement profile at the edge of the vacuum consolidation area has been established. Finally, the proposed methods were applied to a project using the vacuum-drain method at Tokyo Bay in Japan. Comparing the calculated results with the measured field values indicates that the methods can be a useful tool for designing vacuum consolidation project.     

地铁振动在建筑物中的传播和砂垫层减振研究

结合位于上海地铁10号线正上方的某教学楼工程,建立土-结构相互作用的平面有限元模型,研究了砂垫层在地铁振动减振方面的效果以及振动在建筑中的传播规律,同时揭示了地铁振动和地震波的差异,指出地铁振动模拟时模型单元的划分应该考虑地铁振动优势频率的影响,得到了砂垫层地铁振动隔振效果不明显的结论。最后给出了工程实际采用的隔振措施及其他可以采用的隔振措施。     

澳大利亚、新加坡交通行业职业资格建设及启示

介绍澳大利亚和新加坡在交通行业从业人员培训和考试的现状,以及相关职业资格制度的建设,对上海如何加快推进交通行业职业资格工作带来的启示。     

柔性节点钢框架的二阶弹塑性极限承载力研究

本文将有限元与Rayleigh-Ritz法相结合,建立了柔性节点钢框架的二阶弹塑性分析法。本文方法由于具有有限元与Rayleigh-Ritz法各自的优点,因而不仅有效地减少了所需求解的未知量,而且具有内存少、速度快和计算精度高等特点。对算例的分析研究表明,节点柔性将显著影响钢框架结构的稳定和极限承载力,而影响程度主要取决于梁线刚度与节点刚度系数之比EI/K_oι和柱中最大轴压比N/N_Y。经对大量算例结果的分析归纳,本文给出了考虑节点柔性的钢框架极限承载力实用计算方法,计算精度能满足工程需要。     

西部地区煤矿建井存在的一些问题思考

介绍了西部地区白垩系、侏罗系煤系地层岩石特性及软弱岩石井巷支护等问题。结合工程实际,对西部地区矿井冻结工程设计、施工中出现的问题,以及孔隙水含水岩层注浆效果差等问题进行了分析,并提出了相应对策,对西部地区矿井设计和施工具有借鉴作用。