排序方式: 共有64条查询结果,搜索用时 15 毫秒
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同深基坑开挖引起紧邻地铁车站变形特性研究 总被引:3,自引:3,他引:0
旷庆华 《铁道标准设计通讯》2015,(5):130-132,137
紧邻已建成地铁车站单侧基坑开挖卸载会引起车站结构不均匀变形,但目前对其变形机制还缺乏系统认识。结合长沙地区某地铁车站工程实例,基于数值方法对同深基坑开挖引起的紧邻地铁车站结构变形发展变化规律进行分析,并讨论有效控制车站结构变形的主要施工措施。研究结果表明,随着开挖深度的增加,地铁车站围护结构水平变形逐渐增大,且增长的幅度逐渐减小;地铁车站主体结构整体刚度较大,对由基坑开挖引起的土体变形传递具有遮拦作用。 相似文献
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Powder segregation induced by mold filling is an important phenomenon that affects the final quality of metal injection molding (MIM). The prediction of segregation in MIM requires a bi-phase flow model to describe distinctly the flows of metallic powder and polymer binder. Viscous behaviors for the flows of each phase should hence be determined. The coefficient of interaction between the flows of two phases should also be evaluated. However, only viscosity of the mixed feedstock is measurable by capillary tests. Wall sticking is supposed in the traditional model for capillary tests, while the wall slip is important to be taken into account in MIM injection. Objective of the present paper is to introduce the slip effect in bi-phase simulation, and search the suitable way to determine the viscous behaviors for each phase with the consideration of wall slip in capillary tests. Analytical and numerical methods were proposed to realize such a specific purpose. The proposed method is based on the mass conservation between the capillary flows in mono-phase model for the mixed feedstock and in bi-phase model for the flows of two phases. Examples of the bi-phase simulation in MIM were realized with the software developed by research team. The results show evident segregation, which is valuable for improving the mould designs. 相似文献
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《铁道标准设计通讯》2017,(4):131-135
以乌鲁木齐轨道交通2号线高铁站基坑支护方案变更为背景,梳理桩锚-土钉复合支护的受力机理和特点。运用PLAXIS分析基坑开挖周边土体变形和临近桥墩的侧移情况,定量给出桩锚-土钉复合支护的经济性分析。工程实测数据表明,桩锚-土钉复合支护可有效控制基坑侧向变形,实现对临近桥墩桩基础的保护。相对于传统围护-内支撑形式,桩锚-土钉复合支护造价低廉、可节省大量工程投资,经济效益显著。 相似文献
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地铁深基坑支护结构位移动态预测 总被引:5,自引:0,他引:5
利用反分析和已有监测成果,用以弹性抗力为基础的杆系有限元法编制程序。分析计算深基坑的分层开挖和逐层支撑各工况下支护桩的内力与位移,预测各工况下支护桩体的水平位移。以深圳地铁罗湖站安全线深基坑为实例,预测20m和25m桩在不同工况下的水平位移。预测结果与实测结果吻合较好,按预测值对施工方案进行了优化。 相似文献
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Research purposes: By contrast of concept, process, and examples of the partial coefficient design method and the design method based on reliability index, this paper has revealed the essence of the two kinds of design methods, namely for the design method based on reliability index, the concept of probability is directly introduced into design and for the design method of partial coefficient, the probability thought is reflected in the middle of the design, and has analyzed their common and obvious differences, which will provide the guidance for engineering design and research personnel to reasonably choose design method according to the actual situation. Research conclusions: (1) The partial coefficient design method, relatively simple, safe, suitable for conventional design, is a practical design method. (2) Reliable indicator design method, which can give attention to both safety and economy, the design process is complex, suitable for special design, is the ideal design way and the method of scientific research. (3) For the retaining structure engineering design, the partial coefficient method can be adopted. (4) The research conclusion has guiding significance for engineering design and research personnel to choose the retaining structure design method. 相似文献
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拟建的京张城际铁路以隧道方式穿过水关长城,分析列车振动对长城的动力影响十分必要。基于《古建筑防工业振动技术规范》,预测了3种运行速度下的14个隧道点位列车振动对长城的影响。结果表明,隧道列车振动传播到长城基部地面后的地面最大振动速度值较小,低于古建筑的振动速度容许限值。可以认为采取深埋隧道穿越水关长城所在区域,对长城影响较小,深埋隧道方案是可行的。 相似文献
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