PBA工法中边桩参数对结构稳定性的影响研究

以北京地铁6号线北海北站工程为背景,采用FLAC3D数值模拟的方法,研究不同的边桩嵌入深度和边桩直径下地层沉降、边桩水平位移和洞底塑性区的规律。研究分析表明:地表沉降和边桩水平位移随着边桩嵌入深度的增加而减少;当嵌入深度一定时,不同边桩直径下对边桩水平位移的影响大于对地表沉降的影响;嵌入深度与洞底塑性区特性具有明显关系,嵌入深度小会使洞底、洞顶土体产生较大塑性区。     

深厚软基路堤塑料套管桩处理固结及沉降规律

塑料套管桩（TC桩）作为一种应用于深厚软土地基的地基处理技术,具有施工快速、沉降小、承载力高等优点。针对增强体加固软土地基的作用特点,分析研究了TC桩处理地基的固结及沉降规律。根据未贯穿软（弱）土层的TC桩为不透水层及加固层、下卧层为单向固结的假设及孔隙水压力连续条件,将TC桩的加固层及下卧层视为双层复合地基,运用双层地基固结理论获得加固层及下卧层的平均固结度,并在此基础上提出了TC桩处理软土地基的沉降计算方法。之后,结合岳阳至常德高速公路试验段工程对本文研究成果进行验证,结果表明采用本文方法计算的固结度及沉降值与实测成果接近,说明该计算方法是合理的。最后,综合分析了桩长、桩间距对沉降的影响,其结论可为工程实践提供理论指导。     

钢筋混凝土框架结构塑性设计的讨论

介绍了钢筋混凝土框架塑性设计的优点,分析框架结构的承载力极限状态和正常使用极限状态,以及几种主要失效形式,说明塑性设计中需要的几方面的假设。对比国内外对超静定结构塑性设计中关于塑性铰区计算公式的选取,以及对优化设计的分析,给出对钢筋混凝土框架结构设计的一点建议。     

镍／聚四氟乙烯复合电镀新工艺的研究

利用电沉积方法制取了镍/聚四氟乙烯复合膜，研究了电流密度、温度、表面活性剂、预镀等因素对复合镀膜的影响，从而得取了最佳工艺条件，结果表明镀膜质量良好，耐磨性大大提高。     

钢管混凝土轴心受压短柱的徐变分析

在继效流动理论的基础上，对长期荷载作用下钢管混凝土的轴心受压徐变进行了分析。针对钢管混凝土受力的特点，对计算模型进行简化，提出了一维的钢管混凝土徐变计算公式，与文献［５］中基于试验回归得到的徐变计算公式进行比较，结果符合较好。     

Derivation of plastic framing requirements for polar ships

A new International Association of Classification Societies standard for polar ship design, in the form of a unified requirement is being developed by an international committee with representatives from many classification societies and with the active participation of many polar nations. The framing structural requirements have been developed by a combination of analysis of existing rules and ships, finite element (FE) analysis and analytical solutions of plastic collapse mechanisms. This paper describes the derivation of the 3-hinge and asymmetrical shear plastic collapse mechanisms using work–energy principles. Energy methods are robust and well suited for developing design standards. The results are shown to compare well with non-linear FE analyses of frame strength.     

铟电极上电催化还原CO2

采用电镀法制备了In/Cu、In/Fe电极.用电化学测试方法考察了上述电极对CO2在0.2 moL/L的KHCO3溶液中还原反应的电催化活性,并对反应主要产物及电流效率进行分析.实验结果表明,基体上电镀铟有利于CO2的电催化还原,电还原产物主要是甲酸;在几种电极中,In/Cu电极的电催化活性最高,在-1.8 V时获得甲酸的电流效率为32.2%.最后展望了基体电镀的研究方向.     

薄壁圆柱在轴向冲击力作用下的动力学响应

利用有限元软件ABAQUS分析了钢和铝合金薄壁圆柱在轴向冲击力作用下的动力学响应。在相同的参数条件和初边值条件下,通过与相关文献的数值结果对比验证了所取参数的正确性和可靠性。讨论了不同碰撞速度,不同质量比,不同边界条件对平均作用力,塑性铰的形状和个数的影响。数值实验表明,随着碰撞速度的提高,平均作用力会相应增大,撞击薄壁结构的刚性质量块和薄壁结构的质量比对平均作用力没有影响。薄壁结构吸收的能量和薄壁结构本身的几何特性和材料特性将决定变形后塑性铰的个数。     

SMA-13沥青混合料细观模拟分析

为了研究SMA-13改性沥青混合料承受动态荷载时内部的应变特征以及塑性损伤规律,对SMA-13改性沥青混合料试件进行了CT扫描,并进行了动态模量试验,基于CT扫描图像以及动态模量试验结果,利用医学影像学软件MIMICS对试件的局部建立了非均质有限元模型,并利用ANSYS有限元软件进行了应变特征与塑性损伤模拟,通过分析发现,胶砂的极限应变水平是模型宏观应变水平的8～9倍,混合料的塑性损伤多发生在较大骨料的边界处,随温度升高,塑性损伤出现在相同位置,塑性损伤区域扩展增大.     

Design method for steel deck plates under quasi-static patch loads with allowable plastic deformations

Plastic deformation of plates in steel deck structures under heavy vehicle or helicopter wheel loads is common in ships and offshore structures, and is therefore of significant interest to designers of ro-ro/cargo ships, helicopter-carrying ships and offshore platforms. To provide insight into the plastic deformation of plates, the nonlinear elasto-plastic response of stiffened steel plates loaded quasi-statically by a central rigid rectangular indenter is investigated both experimentally and numerically. The numerically-determined stiffened plate permanent deflections compare well with those obtained experimentally. The concept of applying the elasto-plastic method to the design of deck plates under wheel patch loads is introduced, and the design principle of wheel patch loaded plating is studied together with the design criteria. A simple design formula to determine plating thickness is proposed based on an acceptable level of permanent set. Ship-mounted helideck plating design cases are given to illustrate the elasto-plastic method, and comparisons are made between the thicknesses derived using the proposed design formula and those found from Lloyd's Register (LR), Bureau Veritas (BV) and DNV-GL rule requirements.