城市边缘区产业园与农村的协调发展研究

产业园与农村作为城市边缘区的重要组成部分,存在着空间、经济、社区建设及社会保障等方面的问题。研究借鉴了国外"一村一社""工业转移"等实践经验,提出了"村企互动"的发展模式;在明确产业园与农村协调发展的基本思路后,通过统一城乡规划、整合村企空间,鼓励产业合作、共同发展经济,共享服务设施、促进社区融合,提供社会保障、保障最低诉求,转变政府观念、提供政策与财政支持等方法,探索城市边缘区产业园与农村的协调发展。     

Design criteria for impact factors based on dynamic on-site data in railway bridges

To evaluate the dynamic behaviours of bridges, many researchers have analysed interactions between vehicles and bridges with numerical methods instead of field loading tests. However, conventional numerical methods take too much time and cost to evaluate the impact factor of bridges in design and maintenance practice. The objective of this study was to propose improved design criteria by using impact factors based on natural frequency rather than span length of railway bridges using dynamic field load-carrying capacity test database. The improved design criteria use a different methodology than that outlined in the International Union of Railway specifications Code. Statistical regressions are applied to more easily estimate the natural frequency of a bridge with a span length of 20?m or longer with steel plate girder or truss superstructures. Calculated impact factors were compared to impact factors obtained from field measurements. Results indicated that the improved method could provide a very reliable estimation for actual impact factors. Since the suggested impact factor criteria are conservative, the proposed method can be used in design and management stages to consider dynamic effects of railway bridges in a more intuitive manner.     

Minimum void ratio characteristic of soils containing non-plastic fines

The minimum void ratio is an index widely used to indicate the contraction characteristics and the densest state of soils. The minimum void ratio obtained by the traditional test method has been utilized to represent the density of soils irrespective of their fines content despite the restriction (FC ≤ 5%). By considering the effect of the blow count, pore water, and their primary properties, the applicability of the minimum void ratio to soils containing fines was examined with an automatic tapping machine. It was confirmed that the blow count of the traditional method is not sufficient for soils with a high fines content. Furthermore, the presence of pore water had a significant effect on the minimum void ratio of soils containing fines. The characteristics of the cyclic minimum void ratio, which indicates the minimum void ratio obtained throughout the repetition of liquefaction and drainage, were also examined.     

Variance‐based global sensitivity analysis for fuzzy random structural systems

There have been increasing advances in the sophisticated approaches like fuzzy randomness to handle different uncertainties in civil engineering; however, less attention has been paid to the formulation of a sensitivity analysis for fuzzy random structural systems. In this study, the main objective is to present the formulation of fuzzy Sobol sensitivity indices to quantify the influence of fuzzy random structural parameters. Meanwhile, uncertainty in derivation of limit states and acceptance criteria in collapse analysis is addressed briefly and treated using fuzzy model parameters. To show the application of the established sensitivity test, the collapse behavior of a steel moment frame subjected to sudden column removal is evaluated thoroughly. The proposed fuzzy sensitivity indices are determined for the problem and the overall influence of fuzzy acceptance criteria on the collapse assessment is shown using fragility analysis. The results show that the presented fuzzy sensitivity analysis can give detailed insight into the characteristics of fuzzy random systems, and the epistemic uncertainty in derivation of limit states can have significant effects on the reliability‐based collapse analysis. It is worth mentioning that to alleviate high computational demands in fuzzy probabilistic collapse analysis, a neural network metamodel is applied in conjunction with the genetic algorithm which is also of practical value to engineers and researchers.     

城中村改造中的“增长联盟”研究——以珠海市山场村为例

分析了我国城中村改造中参与主体的联盟、组织和作用机制等问题,指出当前我国城中村改造与城市更新的地方政治结构不同,解释城市更新的“增长联盟”框架不能直接套用到城中村改造中去:一方面,城中村改造突破了“增长联盟”的主体关系,投资方与原有村民结成了紧密的联盟关系,打破了原有政府权力和开发资本的联盟;另一方面,增长与反增长的边界变得模糊,在经济利益的影响下,不同参与主体倾向于选择性增长(介于增长与反增长之间)。以珠海市山场村改造为例,实证了上述研究发现,进一步完善和发展了原有的“增长联盟”理论。     

机场工程建设安全管控模式研究——以浦东国际机场三期扩建工程为例

随着信息化、全球经济化的发展,人们出行面临越来越多的选择,特别是航空出行越来越成为更多人的选择,因此 对于民用机场的新建、改扩建等越来越迫在眉睫。民用机场工程建设扩张也带来危机,安全方面的困境层出不穷,安全管理 理念越来深入人心,机场的建设给管理和运行带来更高的要求。大型枢纽机场不能再停留在传统的工程项目管理水平上,而 是要建立科学有效的体系、采取有效的措施,在施工安全管控上加强与完善。以浦东国际机场三期扩建工程为例,以施工阶 段业主方的角度阐述机场工程建设安全管控模式。以期为类似工程建设安全管控提供借鉴和指导。     

部分预制装配型钢混凝土柱抗震性能试验研究

为充分发挥型钢混凝土结构受力性能及预制装配结构施工性能方面的优势，提出了部分预制装配型钢混凝土实心柱(PPSRC柱)和空心柱(HPSRC柱)，结合2个系列10个柱试件的拟静力试验，对两种柱的抗震性能进行了研究。通过对试件的破坏形态、滞回曲线、骨架曲线、耗能能力及变形能力、承载力及刚度退化的研究，并结合各试件的实测应变结果，对柱截面形式、轴压力、配箍率和现浇混凝土强度对PPSRC柱和HPSRC柱抗震性能的影响进行了分析。研究结果表明：PPSRC柱试件的最终破坏形态分为弯曲破坏与弯剪破坏，HPSRC柱试件均发生弯剪破坏，所提出的高强高性能预制混凝土外壳能够很好地与型钢及现浇混凝土协同工作，主要受力方向型钢与外部混凝土之间未发现明显的黏结裂缝；由于内部混凝土的存在，PPSRC柱相比于HPSRC柱拥有更好的耗能及变形能力；轴压力较低、配箍率较大的试件表现出更好的耗能能力及变形能力。通过对两种柱试件的受弯承载力分析可知，中低轴压比的PPSRC柱与HPSRC柱拥有相近的受弯承载力，在同一结构中HPSRC柱可与PPSRC柱沿竖向混合使用，以有效避免柱变截面处的刚度及承载力突变带来的影响。     

配置高强箍筋混凝土框架梁端抗震性能试验研究

进行15个框架梁端试件的低周反复加载试验,其中试件的剪跨比包括1.4、2.5和3.4,试件的受力纵筋为HRB500级钢筋,箍筋为970MPa级PC钢棒和HRB400级钢筋。研究配置高强纵筋和高强箍筋的混凝土框架梁端的破坏特征、滞回曲线、骨架曲线、位移延性和刚度退化等抗震性能和极限承载力,分析平均约束应力（ ）的影响,并利用试验结果对比分析了中国、美国和日本相关标准的受剪承载力计算公式。结果表明：提高 可限制试件裂缝开展,降低破坏程度,使试件滞回曲线饱满,并可提高其抗震性能与极限承载力,但对受弯破坏试件的承载力和位移延性的提高幅度不大,且过大的 会使梁身过强而出现梁端结合面破坏;达到极限承载力时,所有试件的受力纵筋均屈服,受剪破坏试件中PC钢棒箍筋的实测最大应变值为 ;当取 为钢筋实测屈服强度且 ≤3.5MPa时,按《混凝土结构设计规范》（GB 50010-2010）和《高强箍筋混凝土结构技术规程》（CECS 356-2013）计算受剪承载力与试验值之比平均分别为0.91和0.87。     

相邻深大基坑安全距离理论分析与数值模拟

以两相邻深基坑为工程背景,采用极限平衡理论和平面滑裂面假定,对坑间有限土体建立了土压力计算模型。推导出考虑桩土摩擦、土质参数、坑间超载、基坑间距、邻近基坑支撑轴力等因素的主动土压力计算公式,给出了土压力保持不变时的基坑间距,即安全距离b的表达式。参数分析表明:安全间距b随两相邻基坑的开挖深度、桩土摩擦系数的增加而增大,随土体内摩擦角的增大而减小。接着采用PLAXIS有限元软件选取HS本构模型建立两相邻基坑数值模型,对安全距离的各影响因素开展了规律性研究,分析了不同基坑间距下土压力的数值解与本文理论解沿挖深的分布规律,发现二者有较好的吻合性,进一步验证了本文理论的合理性。     

抽水蓄能电站高压压水试验成果分析

结合某抽水蓄能电站高压压水试验资料,分析在高压水作用下岩体的透水率、临界压力等特性。