在既有建筑下修建浅埋暗挖岩石车站的关键技术

在既有建筑下方修建浅埋暗挖岩石车站的工程难度极大,如何保证上部既有建筑的安全和正常使用以及新建工程的安全是设计、施工的难点。以重庆北站(南广场)为例,提出在既有建筑下方修建浅埋暗挖岩石车站的若干关键技术,并通过数值模拟、现场监测进行验证,可为类似工程提供参考。研究结果表明：对大跨度、扁平的单层暗挖车站,在浅埋岩层中近距离下穿建筑物时采用中洞法是合理可行的,通过采取适当的工程措施能避免上部基础产生冲切破坏,有效保护建筑物,中洞结构施工是变形控制的关键工序;对浅埋岩层中的多层多跨地下结构,提出拱柱法的施工方法,解决传统PBA (框—梁—拱)工法应用于岩层时存在的开挖工序多、施工效率低等问题,能有效控制地层及上部建筑变形,其中地下一层结构施工是变形控制的关键工序。该方法对强风化及更好岩层中变形控制严格的地下车站具有重要应用价值。     

管制扇区优化划分的方法及计算机实现技术

扇区划分是空中交通管理的一项重要工作，它直接影响空域的容量和安全性。分析、确定了管制空域结构拓扑描述的数学模型、管制员的管制工作负荷统计方法、工作负荷计算的数学模型等扇区优化设计工作的理论基础，建立扇区划分的数学方法，并编制了基于管制员工作负荷的扇区优化应用软件，实际算例的计算结果验证了扇区优化数学理论基础和应用软件的正确性。     

非政府组织的兴起及其作用

非政府组织作为政府和企业以外的社会组织的第三种形式之一，在当前人类社会活动的不同领域正在发挥着其不可或缺的日益重要的作用。非政府组织概念最初由联合国首先加以使用，并对其合法性做了严格的界定。近些年来，非政府组织在我国也开始发展起来，并且已经在一些社会问题突出的领域，如环境保护、扶贫帮困等方面，发挥其特有的重要作用。随着公共管理的健全和发展，非政府组织应作创新发展。中国作为有重要地位的、在国际上负有重要责任的大国，其非政府组织也应在国际性的活动中发挥与之相应的作用。     

航迹分区处理的实现方法

讨论在搜索雷达分扇区录取目标点迹的前提下,完成目标航迹建立的问题。通过延迟半个扇区处理的方法,有效避免了目标因跨扇区飞行所产生的航迹重新建立问题。在航迹处理过程中,将航迹分类处理,有效地解决了航路交叉问题,同时又利于计算机程序的实现。     

Transportation survey and rideshare matching model for rural communities

A simple and flexible low technology rideshare matching model was developed for a rural area. A brief survey form provided information on distance to work, fuel consumption and currently used transportation mode in conj unction with information on employment location and work schedule. The model developed used a computerized system for proximity matching of potential ride sharers. An existing computer program with detailed modifications was used for data analysis. Unlike other rideshare matching programs, this model relies on grouping by community names to match riders.     

Do reforms reduce the magnitudes of cost overruns in road projects? Statistical evidence from Norway

Although governments often respond to the prevalent cost overruns of transportation projects by reforming the agencies charged with overseeing the construction of projects, the transportation research literature has not provided statistical evidence as to whether such reforms assist in reducing cost overruns. This paper provides such evidence using the Norwegian road sector as a case study. The agency in question was reformed twice, from a monopolistic to a semi-monopolistic organization, and finally, to a fully competitive organization in which road construction was divided out into a separate company and privatized. In this work, we use statistical inferences to explore the related issues. The data set is composed of 1045 projects evenly distributed across the three organizational forms. The results demonstrate that the impact of the reforms has not been equal. The most important impact occurred in the final reform of full competition in which both the cost overruns and delays in construction among larger projects were greatly reduced. The second reform appears to have had a contrasting impact. For transportation research in general, we call for additional studies that will reveal the extent to which efforts carried out by governments (such as reforms) improve the efficiency of these sectors.     

Impacts of combining partial and general equilibrium modelling in freight transport analyses – a forest sector case study from Norway

Abstract

The forest sector in Norway is very transport intensive, accounting for approximately 14% of total domestic freight transport traffic on Norwegian roads. This paper presents an analysis linking a general equilibrium freight transport modelling tool with a partial equilibrium model of the forest sector. The freight transport model predicts transport costs, modal split and transport patterns, and the results are treated as inputs to the forest sector model. The objective of the paper is to analyse the modelling effect of taking forest sector model effects back into the freight transport model and treated as new demand. Compared to a base scenario for the year 2020, we compare analyses with and without this new demand from the forest sector model back into the freight transport modelling tool.     

中国碳中和目标下交通部门低碳发展路径研究

实现碳达峰、碳中和目标（以下简称“双碳”目标）的关键是能源系统绿色低碳转型。交通部门在我国碳排放中占有较大比重且仍在继续增加,加快推进交通部门低碳转型极为迫切。分析了中国交通部门的碳排放现状和主要特点,结合已有的国家政策、目标和以往的研究,提出交通部门的碳中和发展路径。在碳中和目标下,中国需在交通运输结构优化、替代燃料技术推广和能效提升等多方面努力,力争在2030年前实现碳达峰,并在2060年将排放控制在1亿t以内。     

基于中间产品的造船采购成本控制

中间产品是现代造船的一大管理特征.据统计,造船成本中大约有65%-73%是外购材料、设备,其中有大量作业还需要外协加工,该特点决定了船厂对原材料供应商及船用配套企业有着很强的依赖性.因此基于中间产品,梳理造船供应链,选择合格供应商,对控制造船采购成本具有至关重要的作用.     

富地表水浅埋偏压隧道围岩变形的实时监测研究

偏压隧道一般位于风化破碎岩层、堆积层、冲积层或坡积层等较松软地层,埋深往往较浅,在隧道开挖过程中,洞顶下沉较大,难以形成自然平衡拱.通过研究广珠铁路江门隧道典型断面围岩周边水平位移、拱顶沉降和地表沉降的实测数据,分析了隧道开挖引起围岩变形与破坏特征.分析表明,周边水平收敛和拱顶沉降均为开挖初期变化速率较快,开挖一段时间后变形趋于稳定.