铁路隧道钻爆法机械化修建设计关键技术北大核心CSCD

隧道钻爆法机械化修建方法是以全工序高效率大型机械配套为基础,用以解决复杂山区长大山岭隧道安全、优质、高效及经济等施工问题的一种技术方法。文章从隧道设计角度论述了钻爆法机械化修建面临的掌子面安全控制与洞身段变形控制两大关键挑战,并总结了以机械化全断面全地质型施工技术、掌子面稳定性评价方法、掌子面超前主动支护技术、掌子面超前支护“定量化”精准设计技术、低预应力锚杆主动支护技术、早高强喷混凝土主动支护技术、初期支护快速成环封闭技术、围岩形变压力计算方法等为核心的隧道钻爆法机械化修建设计关键技术,为推广应用隧道钻爆法机械化修建方法提供技术支撑。     

重载货车驾驶人驾驶风格识别与量化研究

重载货车驾驶人的激进驾驶风格具有强烈的习惯性特征和风险性特征，一旦养成很难矫正，且极易诱发交通事故。针对现有研究极少关注重载货车驾驶人驾驶风格的不足，本文基于某全国货运监管平台提供的云南省重载货车低频轨迹数据，从风格聚类、风格识别和风格评估这3个方面，提出综合考虑疲劳驾驶特征和超速驾驶特征的重载货车驾驶人驾驶风格分析方法。首先，基于轨迹数据蕴含驾驶人驾驶行为模式的特点，构建表征重载货车驾驶人驾驶风格的疲劳驾驶和超速驾驶特征集；其次，利用因子分析进行特征约简，并采用K-均值聚类方法划分重载货车驾驶人的驾驶风格；然后，构建基于支持向量机的驾驶风格识别模型，并与梯度提升决策树的识 别结果进行对比；最后，基于疲劳驾驶特征和超速驾驶特征的累积分布，建立基于 CRITIC (Criteria Importance Though Intercriteria Correlation)赋权法的重载货车驾驶人驾驶风格量化评估 模型。研究结果表明：经过特征约简，提取的疲劳因子和超速因子能综合反映上述两类特征集 80.838%的信息；根据疲劳因子和超速因子可将驾驶风格划分为4种类别，即稳健型、超速型、疲劳型和危险型，相应重载货车驾驶人比例依次为62.60%、25.02%、7.40%和4.98%；基于支持向量机的重载货车驾驶人驾驶风格识别模型对不同风格的识别准确率均大于97%，整体表现优于梯度提升决策树；基于CRITIC赋权法的驾驶风格评估模型能有效量化重载货车驾驶人的驾驶风格， 其中稳健型驾驶人表现最好，75%以上的驾驶人风格评估总分高于60分；危险型驾驶人表现最差，75%以上的驾驶人风格评估总分低于20分。研究结果可为重载货车驾驶人不良驾驶行为的监测、干预和管理提供理论依据和技术支撑。     

基于自稳式钢支撑基坑支护结构的基坑开挖研究

建筑基坑开挖对周边地表及建筑物影响较大,且其稳定性难以控制。为此,本文提出基于自稳式钢支撑基坑支护结构的建筑基坑开挖方法。以某地铁车站基坑工程为研究对象,采用自稳式钢支撑基坑支护结构——双排围护桩与双排注浆钢管支撑相结合的支护模式,并布设针对建筑物、钢支撑和地表观测点,实时监测基坑开挖后邻近区域地表及建筑物沉降情况。结果表明:三个钢支撑极限承载力均达到1100 kN;采用自稳式钢支撑基坑支护结构邻近建筑物测点地表下沉幅度较小;基坑开挖对周边区域地表沉降影响存在时空效应,在地下水位较高条件下距离较近的周边建筑物受基坑开挖影响沉降显著。     

Electric vehicles revisited: a review of factors that affect adoption

Electric vehicles (EVs) were recently reintroduced to the global car market. These are an improvement over their predecessors in performance and electric driving range. Although the uptake of EVs has been notable in a short period of time, most government goals for adoption have not been met. This paper reviews a growing body of peer-reviewed literature assessing factors affecting EV adoption. Several important gaps in knowledge are identified. First, there is mixed evidence of the effectiveness of government incentives in encouraging EV uptake and particularly little knowledge in regards to issues of timing and magnitude. The literature shows that public charging infrastructure is an important factor associated with EV uptake, though the direction of causality is yet unclear. Public charging infrastructure can ease range anxiety, particularly for battery electric vehicles, but there is little guidance as to the way in which government should best go about ensuring the provision of infrastructure. Lastly, the nascent EV market means that studies primarily rely on surveys about hypothetical situations. There is strong evidence that actual purchases are much lower than consumers’ stated preferences. Improving understanding of this “attitude–action” gap is important to better informing studies of EV uptake over time.     

Effects of job demands and social interactions on fatigue in short sea cargo shipping

Although fatigue is considered an important problem in shipping, little is known about potential mitigating factors or resources for coping. Adopting a Job Demands–Resources framework, this article examines the effects of both job demands (stressors) and resources on fatigue, focusing on social interactions on board as a potential source of social support. Using an incomplete repeated-measures design, the study combined information from documents with surveys on seven cargo ships. Findings indicated that fatigue levels were highest for those working on deck and for individuals at higher hierarchical levels. Higher numbers of port calls (and to some extent lower numbers of days at sea) also increased fatigue levels. By contrast, night watches and the number of days in port had no effect on fatigue. Supportive social interactions reduced fatigue (main effect), but their effect was weaker when the number of port calls increased (interaction effect). All main effects were mediated by individuals’ perceptions of work pressure. Taken together, findings highlight the importance of considering social interactions on board to advance our understanding of stressors and strain in seafaring.     

Personalised feedback and eco-driving: An explorative study

Conventional road transport has negative impact on the environment. Stimulating eco-driving through feedback to the driver about his/her energy conservation performance has the potential to reduce CO₂ emissions and promote fuel cost savings. Not all drivers respond well to the same type of feedback. Research has shown that different drivers are attracted to different types of information and feedback. The goal of this paper is to explore which different driver segments with specific psychographic characteristics can be distinguished, how these characteristics can be used in the development of an ecodriving support system and whether tailoring eco-driving feedback technology to these different driver segments will lead to increased acceptance and thus effectiveness of the eco feedback technology. The driver segments are based on the value orientation theory and learning orientation theory. Different possibilities for feedback were tested in an exploratory study in a driving simulator. An explorative study was selected since the choice of the display (how and when the information is presented) may have a strong impact on the results. This makes testing of the selected driver segments very difficult. The results of the study nevertheless suggest that adapting the display to a driver segment showed an increase in acceptance in certain cases. The results showed small differences for ratings on acceptation, ease of use, favouritism and a lower general rating between matched (e.g., learning display with learning oriented drivers) and mismatched displays (e.g., learning display with performance oriented drivers). Using a display that gives historical feedback and incorporates learning elements suggested a non-verifiable increase in acceptance for learning oriented drivers. However historical feedback and learning elements may be less effective for performance oriented drivers, who may need comparative feedback and game elements to improve energy conserving driving behaviour.     

微振动浅孔控制爆破在基坑开挖中的应用

某地铁盾构始发井处基坑岩层属于坚硬裂隙岩,岩石呈块状或巨块状,采用非炸药爆破方式施工很难对石方进行开挖,且该基坑紧邻小区建筑物及交通要道,炸药爆破极易对周边环境和安全造成影响,因此在基坑开挖中采用了微振动浅孔控制爆破方法。介绍了采用微振动浅孔控制爆破的技术方案(包括爆破参数选择、爆破施工流程及相关工作)和安全防护措施。爆破振动监测及数据处理分析表明,采用微振动浅孔控制爆破技术并制定严密可靠的安全防护措施,能够有效控制爆破飞石、噪声及冲击波,是一种安全、经济、有效的施工方法。     

超大型深基坑对高速铁路桥墩稳定性影响分析

随着近邻高速铁路沿线房地产的开发,建筑基坑施工有可能影响到高速铁路桥梁、路基的稳定性,为了减小基坑开挖产生的不利影响,确保高速铁路行车安全,通过大型有限元软件计算以及现场位移、水位等实时检测手段进行稳定性分析,同时,研究了深基坑开挖及抽水过程对高速铁路桥梁桩基变形的影响规律及范围。结果显示,基坑自身的稳定性及其降水后的水位位置,对高速铁路桥梁桥墩的水平位移有着重要影响,且这种影响关系是复杂的,影响范围较大,因此,不能仅以基坑与高速铁路的距离是否在20m以上作为安全标准,而应根据基坑深度、大小以及需要降水的程度,结合其与高速铁路距离、地层土质力学参数等因素,综合评价其对高速铁路的影响。     

特殊环境下上跨铁路高架桥关键技术应用研究

结合嘉闵高架路(春申铁路段)工程设计实例,详细介绍嘉闵高架路(春申铁路段)工程的桥型选择、孔跨布置以及采用的实施"北竹港河道下穿既有沪春铁路扩孔工程+北竹港河中筑岛"方案、"沪杭客运专线两侧桥墩钢盖梁方案"、"桥梁关键施工工艺预设计"、"既有百年低高度T梁桥套箱改造成框架桥方案"及"沪杭客运专线特大桥桥墩承台近距离框架桥基坑围护方案"等关键技术。     

LNG低温管托的结构特点及材料选用

LNG(液化天然气)在输送过程中,冷量泄漏易汽化产生BOG气体,会严重影响接收站的经济收益。在设计过程中,考虑低温管托需承重,其选用的保冷材料与管道本体不同,选择合适的结构和材料,可以最大限度地减少冷量泄漏。文中介绍一种低温管托的设计要求、结构特点和材料选用,该管托在实际应用过程中表现出良好的保冷性能且施工方便,值得推广应用。