康明斯高强度球铁曲轴研究

比较了由三种不同牌号材质所加工出的6BT球铁曲轴疲劳强度及安全系数,探讨了不同的材质和强化工艺对6BT球铁曲轴的影响,为选择合适的球铁材料及提高6BT球铁曲轴的性能提供了参考。     

未打穿半透水下卧层的竖井地基固结解析研究

本文发展了考虑半透水下卧层的未打穿竖井地基固结解析理论 ,并分析了此类地基的固结基本形状。研究表明 ,半透水边界对竖井地基固结过程有较大影响 ;下卧层半透水综合参数 Rv 越大 ,固结越快 ;当其增大到一定程度时 ,其影响可忽略 ,即半透水边界可作为完全透水边界来处理     

南京疏港公路近距离路堑开挖对栖霞山铁路隧道结构的影响研究

南京市龙潭港疏港一级公路在栖霞山铁路隧道北侧呈近距离平行延伸，挖方路基距离铁路隧道的最小净距仅为11．9m，按相关规范推算现有铁路隧道宽9m，高8．5m。为了确保施工期间沪宁铁路栖霞山隧道的正常运营，必须对设计路线给予正确合理的分析评估，以保证设计方案合理、参数取舍可行，最终对路堑的施工方法、施工方案提出了工程预防措施。     

Spillback congestion in dynamic traffic assignment: A macroscopic flow model with time-varying bottlenecks

In this paper, we propose a new model for the within-day Dynamic Traffic Assignment (DTA) on road networks where the simulation of queue spillovers is explicitly addressed, and a user equilibrium is expressed as a fixed-point problem in terms of arc flow temporal profiles, i.e., in the infinite dimension space of time’s functions. The model integrates spillback congestion into an existing formulation of the DTA based on continuous-time variables and implicit path enumeration, which is capable of explicitly representing the formation and dispersion of vehicle queues on road links, but allows them to exceed the arc length. The propagation of congestion among adjacent arcs will be achieved through the introduction of time-varying exit and entry capacities that limit the inflow on downstream arcs in such a way that their storage capacities are never exceeded. Determining the temporal profile of these capacity constraints requires solving a system of spatially non-separable macroscopic flow models on the supply side of the DTA based on the theory of kinematic waves, which describe the dynamic of the spillback phenomenon and yield consistent network performances for given arc flows. We also devise a numerical solution algorithm of the proposed continuous-time formulation allowing for “long time intervals” of several minutes, and give an empirical evidence of its convergence. Finally, we carry out a thorough experimentation in order to estimate the relevance of spillback modeling in the context of the DTA, compare the proposed model in terms of effectiveness with the Cell Transmission Model, and assess the efficiency of the proposed algorithm and its applicability to real instances with large networks.     

中、下承式拱桥吊索张力测定的振动法实用公式

考虑吊索弯曲刚度和两端固定边界条件的影响，引入参数简化吊索张力与其横向振动频率之间关系的超越方程，采用数值计算和曲线拟合的方法，推导出了考虑吊索弯曲刚度和吊索两端边界条件影响的，由吊索振动频率计算吊索张力的实用计算公式，并将该公式运用于下承式拱桥施工现场吊索张力的测定。通过与现场实测数据的比较表明：该公式具有较高的精度和一定的实用价值。     

挤密砂桩加固高速公路软基的现场试验研究

通过在广贺高速公路北江特大桥桥头设置软基试验段,对挤密砂桩加固软基处理进行标贯、静力触探和监测等试验,对挤密砂桩抗砂土液化和加固效果方面进行研究,根据得出的数据进行分析,总结了挤密砂桩在处理砂土液化及软土地基处理方面的一些主要效果及特点。     

Marine Social Science for the Peopled Seas

Coastal communities, indigenous peoples, and small-scale fishers rely on the ocean for livelihoods, for subsistence, for wellbeing and for cultural continuity. Thus, understanding the human dimensions of the world’s peopled seas and coasts is fundamental to evidence-based decision-making across marine policy realms, including marine conservation, marine spatial planning, fisheries management, the blue economy and climate adaptation. This perspective article contends that the marine social sciences must inform the pursuit of sustainable oceans. To this end, the article introduces this burgeoning field and briefly reviews the insights that social science can offer to guide ocean and coastal policy and management. The upcoming United Nations Decade of Ocean Science for Sustainable Development (2021–2030) provides a tremendous opportunity to build on the current interest, need for and momentum in the marine social sciences. We will be missing the boat if the marine social sciences do not form an integral and substantial part of the mandate and investments of this global ocean science for sustainability initiative.     

乡村道路砂石路面沥青稀浆封层技术应用

从材料选择、施工工艺、质量控制、实用效果等几方面对乡村道路砂石路面沥青稀浆封层技术做了探讨。     

盾构站内过站条件下地铁明挖车站上部结构施工支撑方案研究

昆明轨道交通4号线苏家塘站为盾构整机站内过站车站,受两迁一改和地质条件影响,土建施工进度较计划滞后。为满足后续盾构过站和二次始发后,轨道运输车辆通行对车站站台层通行净空的基本要求,提出2种可以满足车站上部结构继续施工的支撑方案--门式支架支撑方案、中板结构加强方案。通过理论分析结合有限元数值仿真模拟,综合比较方案实施对车站施工进度的基本要求、对后续盾构施工工期影响、经济性等6个方面,认为2种支撑方案均能够提供上部结构施工的支撑反力,但应充分结合土建施工进度及盾构过站时间要求选用支撑方案,以便能够更好地控制投资并满足工期要求。     

循环经济在发达国家的应用

循环经济作为新型工业化道路的最高形式,是预防和控制污染,提高资源综合利用率,实现经济、社会和环境综合效益的根本途径,是一项可持续发展的系统工程。通过简要介绍循环经济的基本特征,结合发达国家发展循环经济的实例,研究循环经济的实现策略,总结发达国家的成功经验,以期对我国发展循环经济有一定借鉴作用。