盾构隧道结构耐久性问题思考

Structural durability of shield tunnel lining is a trans scale problem from mesoscopic material to macroscopic structure. With increasing amount of shield tunnel construction in China, the issues related to structural durability become more prominent. In this paper, the typical applications of shield tunnel lining in China and other countries are introduced. The service conditions and diseases of shield tunnel lining structure are then analyzed. The factors affecting the structural durability of shield tunnel lining, such as material, design, environment, construction, management and maintenance, are summarized. The research results and progress related to structural durability of shield tunnel lining are then reviewed in terms of tunnel durability, durability evaluation and prediction, durability ensuring techniques. Finally, the existing problems and future research directions in structural durability of shield tunnel lining are discussed in terms of durability ensuring techniques, impact of diseases and accidents, tunnel evaluation and rehabilitation, arrangement of secondary lining and establishment of dynamic evaluation system for structural durability.     

整体桥H型钢-RC阶梯桩与土相互作用拟静力试验

以H型钢-RC阶梯桩模型试验为背景,进行了2根H型钢-RC阶梯桩(HS-RC-0.25、HS-RC-0.50)及1根H型钢桩(HS)的低周往复荷载拟静力试验;在桩顶施加水平位移荷载,埋设应变片与土压力计,采用特殊设计的桩身水平变位测试方法,得到了H型钢-RC阶梯桩桩身破坏特点、沿桩深方向的桩身水平位移与应变、骨架曲线和滞回性能曲线;利用OpenSEES对比分析了桩顶自由与固定条件下阶梯桩桩顶水平变位能力,得到了阶梯桩水平承载力折减系数与转化系数,对比了利用折减系数得到的模型桩水平承载力计算值与试验值。试验结果表明：H型钢桩的桩顶弹性变形为2～25 mm,其水平变形能力强,承载能力好,加载全过程滞回环饱满,耗能效果好;刚度比对阶梯桩的破坏模式无显著影响,阶梯桩的上段钢桩均无明显的屈曲破坏,变截面处混凝土严重剥落且破坏位置相同;随刚度比增大,阶梯桩-土体系屈服位移及屈服荷载均提高,HS-RC-0.25较HS-RC-0.50桩顶屈服位移减小了29.15%,桩身应变突变减小;阶梯桩的滞回环在加载初期因为滑移表现为捏拢状,而在加载后期过渡为饱满的梭形,耗能效果良好,HS-RC-0.50加载全过程...     

Eradication of algae in ships＇ ballast water by electrolyzing

In order to verify the effectiveness of electrolytic treatment on ships＇ ballast water, experiments are carried out by a pilot system in laboratory. The raw seawater and seawater with different concentrations of different algae are simulated as ships＇ ballast water. The algae in the raw seawater can be killed if it is treated by electrolysis with an initial residual chlorine concentration of 5 mg/L. If the seawater with one kind of algae （Nitzschia closterum, Dicrateria spp., or Pyramidomonnas sp.105cells/mL） is treated by electrolysis with an initial residual chlorine concentration of 5 mg/L the alga can be sterilized, If the seawater with one kind of algae （Dunaliella sp., Platymonas or Chlorella spp.） is directly treated by electrolyzing with an initial residual chlorine concentration of 4 mg/L, the instant mortality changes with the concentration of different algae. However, after 72 hours, in all treated samples, there are no live algal cells found.     

Quasi-static Compressive Behavior of U-type Corrugated Cores Sandwich Panels

金属基夹层板在船舶耐撞及防护结构设计中的应用研究成为国内外研究热点,夹层板具有高效的吸能特性,尤其是夹芯层结构.以U型折叠式金属基夹层板为研究对象,对夹芯层开展横向压皱力学行为实验研究,利用有限元软件Abaqus对其进行数值仿真研究,对比分析夹芯层结构的压皱力、变形、吸能和平均压皱强度等参数,数值仿真分析了不同单元变形模式(ModeI和Mode II)、初始变形对压皱性能的影响.研究表明:试验研究与数值仿真分析得到的U型夹芯层结构压皱性能吻合较好.夹芯层结构变形模式对结构的压皱行为及其压皱性能有显著的影响,变形模式I的吸能效率、平均压皱强度等性能参数均高于变形模式II.初始缺陷决定了结构的变形模式,随着初始塑性位移缺陷增加夹芯层结构的压皱性能下降.     

加筋土地基试验研究

通过对一综合利用加筋土技术的工程进行现场测试，着重研究了反映加筋土地基工作性能的诸多指标（如竖向土压力、筋带内力、沉降特性、非加筋区地表运动）的分布规律，并探讨了加载对以上指标的影响。     

Eradication of algae in ships’ ballast water by electrolyzing

1 Introduction1 The introduction of invasive marine species into new environments by ships’ ballast water, attached to ships’ hulls and via other vectors, has been identified by the Global Environment Facility (GEF) as one of the four greatest threats t…     

非接触式IC卡在轮渡售检票系统的应用

介绍了轮渡非接触式IC卡售检票系统的组成和工作原理,该设备在实际应用中具有很高的可靠性和安全性,实际应用效果良好。