北京地铁6号线盾构区间叠落隧道设计思考

近年来地铁工程受城区规划条件、既有建构（筑）物和车站设置形式等因素影响,出现了大量的近接工程,盾构区间叠落隧道作为自身近接工程的一种已在地铁6号线实施,作为北京第一批开通运营的区间叠落隧道,本文通过对其受影响较大的先实施下方隧道的受力特点进行重点分析,找出控制工况,核算结构受力,确定管片加强及隧道内临时台车支护方案,并通过沉降变形和实施效果监测的分析,满足规范和风险控制要求。     

长益城际宁乡Q2网纹黏土工程地质特性研究

研究目的:长沙至益阳城际铁路宁乡境内广泛分布Q2网纹状红黏土,这种土体性质有很强的区域性,城际铁路对路基的沉降变形控制十分严格,所以针对此类路基如何采用合理的处理方法是一个关键问题.为了全面了解宁乡Q2网纹状红黏土的工程性质,结合现场地质调绘、钻探、原位测试及室内试验,对土体的形态成因、物理性质、强度特性、变形固结特性以及膨胀特性进行系统的探讨,为路基设计提供可靠的依据.研究结论:网纹状土是在湿热的气候条件及多水的环境下,红黏土经多次淋溶沉淀作用而形成;网纹土的孔隙比比一般黏土要大,饱和度一般低于90％,为非饱和土;液限及液性指数较高,为高液限土;天然状态下网纹土的强度较高,一般处于硬塑～坚硬状态,承载力可达200 kPa;网纹土属于中压缩性土,下层网纹土压缩性比上层土要高;网纹土是典型的超固结土,表层的超固结比达到15.4;网纹土一般为弱膨胀土.     

A self-regulation traffic-condition-based route guidance strategy with realistic considerations: Overlapping routes,stochastic traffic,and signalized intersections

Variable message signs that provide various types of route guidance information have been widely deployed in large cities. To release proper information only using easily collected data, a simple traffic-condition-based (TCB) route guidance strategy was recently proposed. The strategy works based on the estimation of free-flow and congested traffic conditions and is capable of approximating user optimal equilibrium stably. Due to little consideration of the complexity of urban road networks, the TCB strategy is still away from field applications in urban areas. To further push the strategy toward field tests, this article improves the TCB strategy in the following aspects: supplementing the strategy with a self-regulation ability by considering existing traffic conditions; decomposing link capacity to solve the problem of overlapping routes by comparing link capacity on alternative routes; coping with stochastic traffic; and the impact of signalized intersections by utilizing aggregated data. A scenario for an urban road network in Beijing, China, is simulated to test the improved strategy, and the simulation results clearly indicate the effectiveness of the proposed improvements. The improvements extend the TCB strategy on moderately complicated urban road networks, and still have the advantages of simple diversion rules, easily obtained input data, and stable and effective diversion processes.     

小间距长距离上下重叠盾构隧道施工关键技术

针对重叠隧道小间距、长距离的特点,根据三维数值模拟分析结论提出“先下后上”的总体施工原则,重点阐述盾构掘进控制、夹层土注浆加固和洞内临时支撑台车隧道加固等关键措施,通过监测结果有效验证了其成功,可为今后的重叠隧道设计、施工管理提供经验借鉴。     

西安地铁左右线交叠转换盾构施工变形规律研究

交叠隧道在施工过程中对周围地层存在反复扰动,针对其力学行为和变形规律的研究十分有必要。以西安地铁临潼线左右线交叉叠落盾构隧道施工为背景,研究线路左右线隧道空间交叉转换施工下周围地层的变形规律及后施工隧道(左线)对已完成隧道(右线)的扰动情况。研究表明:隧道施工完成后,地表沉降槽整体呈条带状且沿区间走向分布;地表沉降随隧道垂直交叠程度的增加而增加,地表沉降最大值为9.79 mm,位于左右线完全垂直交叠位置处;左线隧道对先施工完成的右线隧道的影响主要表现为侧向推挤和增大地层附加应力的作用,但在垂直交叠位置扰动影响较小;施工扰动引起右线隧道最大水平位移为1.75 mm,最大沉降为1.97 mm。     

第34届海洋、离岸及极地工程国际会议(英文)

正St.John's,Newfoundland,Canada,May 31-June 5,2015 OMAE2015 is the ideal forum for researchers,engineers,managers,technicians and students from the scientific and industrial communities from around the world to: meet and present advances in technology and its scientific support;     

On Social Distress,Littering and Nature Conservation: The Case of Jisr A-Zarka

Studying perceptions of litter and littering behavior among marginalized, poor and undeveloped communities is important since these populations frequently inhabit important conservation sites. Jisr-A-Zarqa ("Jisr"), is a coastal town on the Mediterranean shores of Israel and one of Israel’s poorest, densely populated communities. Litter accumulation in the streets and beach of Jisr is a known problem, and its proximity to the nearby stream and beach makes the study of littering important for the conservation of the coastal and marine habitats. I studied residents’ perceptions of litter and littering practices and found that littering and waste accumulation are surface indicators of profound underlying social, economic and political constraints, problems and distresses. These must be considered as an integrated context and addressed when designing litter-reducing interventions.     

Social Networks of Alaska Fishing Communities

Fishing community social networks function as channels for transfer of fishery knowledge, resources, and business transactions that help mitigate risks and shocks associated with altered access to fishery resources. Research on such networks in Alaska is limited despite their cultural importance and community reliance on fisheries. We contribute to scholarship of fishery social networks by assessing Alaska fishing community perspectives of challenges related to fisheries policy and management, and the existing social networks that aid in overcoming these challenges. Our findings show that the greatest challenges fishing communities face pertaining to fishery management are high costs of participating in catch share programs, restricted subsistence fishing activity due to decline in salmon, and complex regulations. Social networks exist for coping with these challenges; fishery information, and resources such as food, fuel and medicines are shared between communities. However, networks for accessing fishery support services are centralized in fewer larger communities and hubs such as Anchorage. Smaller and remote communities are the most compromised in this regard given the distance they must travel to access fishery support services. Leveraging social networks for sharing resources and improving fishery support services in smaller communities will increase their adaptive capacity and ability to maintain participation in Alaska fisheries.     

高速铁路CPⅢ网区段搭接数据处理研究

研究目的:高速铁路轨道控制网(CPIII)相邻区段的搭接是否合理将直接影响轨道的平顺性,影响轨道长短波检测的计算结果。本文针对国内轨道控制网CPⅢ两种主要的区段衔接方法,结合工程实际进行了研究。给出两种搭接计算的算法,对两种算法的结果进行比较,并对其优缺点进行分析对比;对搭接平差前超限情况的处理方法进行阐述,为类似工程应用提供参考。研究结论:在相邻两段CPⅢ网独立平差后搭接区点的坐标较差≤3 mm情况下,两种方法得到的搭接平滑结果,均可以满足轨道长短波检测的需要。从测量理论和实践应用出发,严密平差搭接的方法应该更可靠,搭接数据处理的可操作性更强,更适用于工程测量实际情况。     

柴油机进气管瞬态流动均匀性三维数值模拟

运用计算流体力学方法对柴油机进气管瞬态流动过程进行了三维数值模拟,讨论了在进气重叠期内,不同工况下进气管内部流场的变化情况。分析了柴油机进气增压压力、转速以及进气重叠时间对各进气歧管出口空气质量流量、进气分配质量、进气最大不均匀度的动态影响。计算结果表明:柴油机进气增压压力越低,进气最大不均匀度越大;进气重叠角越大,进气最大不均匀度也越大;柴油机低转速工作时的进气最大不均匀度要高于高转速最大不均匀度。通过提高进气增压压力、合理优化进气管几何结构,可以减小柴油机在进气过程中出现的进气分配不均匀现象。