铁路小件货物快运产品开行方案研究

随着我国铁路小件货物快运市场的需求日益增长,为了提高铁路小件货物快捷运输产品的市场竞争力,需要提供多等级的小件货物快捷运输服务,并配套相应产品的开行方案.文中以京广通道为例,提出在该通道上组织3种速度等级的小件货物快运产品———高速行邮专列、特快行邮专列、行包专列,并制定了该通道2015年的小件货物快运产品开行方案.     

采用减隔震装置的轨道交通槽形梁桥动力性能

从桥梁减隔震的机理出发,以我国正在建设的某轨道交通槽形梁桥为工程背景,采用非线性有限元及车桥耦合振动分析理论,综合研究了轨道交通槽形梁桥采用减隔震装置前后的抗震性能和轨道交通车辆的走行性.研究结果表明,采用减隔震装置可明显改善轨道交通槽形梁桥的抗震性能,并能确保轨道交通车辆日常行车的要求.     

基于同心圆分簇的无线传感器网络路由协议的研究

针对无线传感器网络中LEACH协议的簇头分布不均匀以及不适合远距离传输数据的缺点,提出一种基于同心圆的分簇路由协议(CBCR).CBCR不仅改进选簇方法,而且引入管理节点负责簇头的选举.给出该协议的实现过程,通过与LEACH的比较,证明该协议能有效延长网络存活时间.     

后12.5 m时期长江口航道面临的机遇、挑战与对策*

历时40年研究和13年建设的长江口深水航道治理工程已于2011年5月实现了12.5 m深水航道正式通航,长江口航道体系格局因此发生了历史性变化,跨入了后12.5 m时代.在对长江口航道现状及问题分析的基础上,探讨后12.5 m时期长江口航道可能面临的各种机遇和挑战,并提出相应的治理对策.     

钦州港总体布局规划方案泥沙回淤研究

为研究和分析广西钦州港研究总体规划方案实施后港池及航道泥沙淤积情况,在二维潮流、波浪数学模型研究成果及现场水文测验和底质分析的基础上,利用泥沙冲淤计算公式,采用正常天气及台风天气情况,对造成港池及航道淤积的悬移质和推移质量值分别进行计算和分析,可为后续工程建设中的泥边淤积研究工作提供参考。     

Distributed mass/discrete floe model for pack ice rheology computation

A new model, called the distributed mass/discrete floe model, is proposed for performing practical computations of mesoscale pack ice rheology. This model possesses the advantages of both the continuum and the discrete element models: it can express the discrete nature of pack ice, for which it is difficult to use a continuum model, and requires a much shorter computation time than a discrete element model. The pack ice is divided into ice bunches in which the floes, assumed to be distributed uniformly, are modeled as inelastic disks or rectangles floating on the water. The ice interaction forces are formulated from the relationship between the impulse on the bunch and the variation of momentum in the bunch. The ocean flow is calculated simultaneously with the floe movement using a multilayer model. In a circulating water channel, drift tests of physical model floes were performed in order to investigate the characteristics of their motion and interaction with ocean structure models. Near the structure, the floe motion depends on the floe shape. Disk floes show a lateral motion in front of the structure. They flow out around both sides of the structure and the number of floes in front of the structure decreases with the lapse of time. On the other hand, rectangular floes scarcely flow laterally. The number of floes in front of the structure remains constant over time. These experiments indicate that when the motion of pack ice around a structure is simulated, it is important to consider the floe shape. The disk floe motion and the rectangular floe motion can be regarded as extreme cases of pack ice motion. Actual pack ice motion may be between these two extremes. Computations were carried out using the distributed mass/discrete floe (DMDF) model. Simulation results were compared with the circulating water channel experiment results and sea ice motion in the southern part of the Sea of Okhotsk. The DMDF model predicted the circulating water channel drift test results quite closely. The DMDF model results also compared quite well with the sea ice motion.     

黄河中卫段复合型滩险整治技术

对兼具"浅、急、弯、险"特点的黄河宁夏中卫下滩河段的复合型滩险整治技术进行研究。在深入分析滩性的基础上,提出多方案设计,通过物理模型试验优化比选。试验表明:挖槽上段采用复式断面、增加滩险进口段宽度和深度,有利于减小滩段水面比降、减小流速。尽管上段水位降幅较大,给上游河段带来不利影响,但整治效果最佳。工程实施后通航水流条件良好,航道条件得到有效改善,为类似滩险的整治提供参考。     

长江澄通河段通州沙西水道整治工程对分流比影响研究

为增加长江澄通河段沿江深水岸线资源,拟进行通州沙西水道整治工程,主要包括边滩圈围工程、洲头潜堤工程、西水道疏浚工程。利用一二维耦合潮流数学模型,模拟计算不同整治方案实施前后的汊道分流比,分析研究工程对通州沙河段的影响。研究结果表明:边滩圈围和潜堤工程、西水道航道疏浚工程、上游径流条件等都将影响通州沙西水道的分流比;仅仅实施边滩圈围和潜堤工程,将减少西水道分流比,而疏浚工程将使西水道分流比有所增加;整治工程实施后,通州沙河段分流比的改变程度主要取决于西水道的疏浚深度,因此,为维持该河段河势稳定应慎重选择西水道的疏浚尺度。     

三峡升船机下游引航道非恒定流波动特性试验研究*

通过1:80的三峡枢纽及下游引航道整体物理模型研究了典型的大坝泄洪、电站调峰、船闸泄水及其叠加工况下的升船机下游引航道非恒定流波动特性。结果表明：三峡枢纽下游引航道内的水位波动是引航道波流运动和两坝间流量差引起的河道涨、落水长波耦合叠加的结果。枢纽进行百年一遇洪水调节时升船机下闸首水位波动最大小时变幅061 m/h。当大坝泄洪单次调节流量小于2 000 m3/s时,升船机下闸首水位波动小时变幅小于042 m/h。电站调峰运行时,升船机引航道水位波动首波幅值随流量变幅和变率的增大而增大,最大小时变幅则取决于流量变幅和两坝间净流量大小。船闸双线同时泄水时升船机下闸首水位最大小时变幅018 m/h,基本不影响升船机运行。     

连云港港30万吨级航道工程抛泥悬浮物扩散观测研究

依托连云港港30万吨级航道工程,分析了ADCP走航式测沙技术应用于含沙量较低的连云港淤泥质海岸的可行性,重点研究主航道疏浚土在抛泥作业过程中产生的悬浮物扩散运动规律及其对连云港徐圩港区航道回淤的影响。研究成果可为连云港港30万吨级航道抛泥作业的改进提供参考。