160 km/h梯形轨枕轨道安全性、平稳性及轮轨振动特性在线实测

全面介绍梯形轨枕轨道在铁道科学研究院国家铁道试验中心R1432m环行道上开展安全性、平稳性及轮轨振动特性测试的方案、测试指标、评判标准及测试结果。采用8辆编组160 km/h动力集中电动车组,测试速度为100、120、140、165 km/h,测试对比断面包括2种梯形轨枕及环行道既有有砟轨道,测试指标包括脱轨系数、轮重减载率、轮轨横向力等安全性指标、钢轨及梯形轨枕垂横向动态变形、车体垂横向振动加速度等稳定性指标、钢轨垂横向振动加速度等轮轨振动特性指标及梯形轨枕应力变化等,上述各项指标的实测结果均低于相关规范标准的限值,且基本与有砟轨道对比断面的测试数据相近,表明梯形轨枕在安全性、稳定性及轮轨振动特性方面可满足160 km/h速度级线路的应用要求,可为该速度级的轨道减振技术提供借鉴与参考。     

城市轨道交通高架线噪声源强取值研究

随着车辆噪声规范的不断完善及钢轨打磨技术的成熟,车辆系统噪声及轮轨噪声有明显改善。济南轨道交通R1号线环评报告参考北京地铁13号线的监测结果,采用93d B作为噪声源强的合理性有待验证。为了使噪声源强取值更加科学,能够更经济合理地进行城市轨道交通高架线降噪方案设计,依靠专业的测试机构,按照环评导则中要求的测试方案对南京机场线(S1线)以及宁天城际(S8线)高架线进行噪声源强实地测试,修正后得出的噪声源强最大值为85 d B。因此,93 d B作为噪声源强参考取值已经不再适用。R1号线按照85 d B进行设计,将节省降噪措施造价约3 000万。     

杭州湾跨海大桥北航道桥斜拉索减振研究

运用福斯(Foss)迭代法求解设置黏性剪切阻尼器(VSD)减振拉索的振动方程,得到复特征值和对数衰减率。以对数衰减率大于等于0.03为目标函数,对杭州湾跨海大桥北航道桥斜拉索减振用VSD进行优化设计,并对安装VSD的减振效果进行分析。结果表明:减振拉索的每阶模态均有对应的VSD最优插板面积,高阶模态的最优插板面积小于低阶模态,高阶模态的对数衰减率受插板面积的影响比低阶模态大;在不考虑其他因素条件下插板面积大于150cm2时便可有效抑制斜拉索的各种风致振动;高阶模态的最大对数衰减率所对应的温度高于低模态最大对数衰减率所对应的温度,低温时低阶模态的对数衰减率大于高阶模态的对数衰减率,温度较高时高阶模态的对数衰减率大于低阶模态的对数衰减率。杭州湾跨海大桥北航道桥斜拉索安装VSD后,对数衰减率从0.015～0.0196提高到0.03～0.11,有效地减小了斜拉索的各种风致振动,达到了减振效果及设计目标。     

广东西部沿海铁路江门南站软土土性参数随机场特性研究

研究目的:广东西部沿海铁路江门南站范围内分布有较厚的软土,其成因为潭江入海口海陆交互相冲积,土性主要为淤泥质黏土和粉质黏土,局部有沙砾夹层,为了满足承载力及工后沉降的要求,路基基底必须采用复合地基进行加固。合理选择土性参数是复合地基设计的关键,由于土体是在自然条件下形成的,其性质表现出很大的变异性,所以采用概率分析方法设计复合地基显得更加合理。土性参数随机场特性研究可以为复合地基概率设计方法提供依据,本文利用CPT资料对江门南站软土土性参数的随机场特性进行了研究。研究结论:形成了比较系统的随机场研究方法,得到了主要土层的方差折减函数;统计得到了压缩模量、承载力及抗剪强度指标的均值和方差,利用方差折减函数对方差进行了修正,为路基概率设计方法提供依据。     

五跨连续拱桥落架施工控制分析

利民桥为5跨连续拱桥,以其落架施工为研究背景,采用刚度折减的方法进行有限元模拟分析,并对应力、变形进行监控。通过实测值与理论值的对比分析可以看出,文章采取的落架方案满足设计要求,对同类桥梁的施工具有参考意义。     

Experimental investigations on the damping effect due to passengers on flexural vibrations of railway vehicle carbody and basic studies on the mimicry of the effect with simple substitutions

The effect of passengers on a railway vehicle is usually considered as additional mass in designing a carbody. However, previous studies by means of stationary excitation tests or running tests using actual vehicles indicate that passengers behave not as mass but as damping. In this paper, the authors examined the passengers' damping effect under controlled excitation conditions on a roller rig through a series of excitation tests using a commuter-type vehicle. Large and multi-modal reductions of flexural vibrations of the carbody were observed when passengers existed. Influences of the number of passengers, distributions and postures of passengers were investigated. The authors also tried to mimic the damping effect by passengers using flexible tanks filled with fluids. Three kinds of fluids which have different viscosities have been tested. As a result of the excitation tests, good vibration reduction effects were observed by applying those tanks, and it has been found that the flexible tanks filled with fluids bring about vibration reduction effect (including multi-modal reduction) which is equal to or rather better than the case of similar mass of passengers in the carbody; the difference of viscosity gave little affect on the damping abilities. From these measurement results, a possibility of realising effective damping devices against flexural vibrations of railway vehicle carbodies representing passengers damping effect, in a simple, economical and environmental friendly way, has been demonstrated.     

溶液燃烧法制备TiV_(0.1)Mn_(0.1)Er_(0.01)O_x催化剂催化还原NO_x的性能研究

为了拓宽选择性催化还原NO_x钒基催化剂的活性温度窗口,采用溶液燃烧合成法制备了TiV_(0.1)O_x催化剂,依次加入Mn元素与Er元素形成新的催化剂,分别对它们进行了SCR活性及选择性测试,发现负载Mn元素可以提高钒基催化剂的低温活性,同时也会降低钒基催化剂的高温活性,负载适量的Er元素可以提高钒基催化剂的高温活性和N_2选择性。利用N2吸附脱附法进行BET比表面积和孔容孔径分析,发现负载Er元素增大了比表面积,进而提升了催化剂活性。利用X射线衍射(XRD)图谱进行晶体结构分析,所有催化剂样品均没有发现VO_x,MnO_x或ErO_x的衍射峰,说明溶液燃烧法制备的催化剂活性组分在TiO2颗粒上呈无定型态分布,分散度高。最终优选出最佳Mn和Er比例的TiV_(0.1)Mn_(0.1)Er_(0.01)O_x催化剂,在160~470℃之间保持80%以上的NO_x去除率。     

轻型汽车CO2排放测量不确定度评定

CO₂排放是汽车污染物排放检测的一项重要技术指标,它表征的是汽车排出污染物的多少和车辆能耗高低的参考标准之一,用以控制汽车使用中产生的污染物排放量,避免对环境产生损害。按照GB 18352.6-2016《轻型汽车污染物排放限值及测量方法(中国第六阶段)》的规定使用全球统一的轻型车测试循环工况进行常温下冷启动后污染物排放试验,并对测量结果进行不确定度评定。文章阐述了轻型汽油车CO₂排放测试所用的测试原理、法规工况曲线、测试设备、数学模型等,通过分析影响试验结果的各因素来源,综合计算得出轻型车CO₂排放测试结果的扩展不确定度和相对扩展不确定度。     

Traffic safety,usability and streetscape effects of new design principles for major urban roads

An important aspect of area-wide traffic calming concepts is the integration of major urban roads, because 70 to 80 percent of all urban accidents occur on major roads. Traffic calming which is primarily based on the locational shift to such main thoroughfares is socially injust, because — in spite of all disturbances on those streets — about one quarter of the urban population live there. Social justice can only be somewhat achieved if the expenditures for traffic calming and streetscaping are not used — as today is most common — for accumulating the advantages in the low traffic side streets, but aimed at a partial balance and compensation for the strains caused by car traffic on the major streets. Some compensatory measures and new design principles will be discussed. Backgrounds are the experience in six German model cities of area-wide traffic calming, several research projects and the discussion about new guidelines for major urban roads. Where traffic and environmental burdens focus, the concentration concept should be extended by compensatory measures. That is the state of discussion in Germany examplified by nine topics.This is an edited version of a speech presented by the author at the International Conference Living and Moving in Cities in Paris, January 1990.     

上软下硬地层地铁隧道与近接桥梁桩基的相互影响分区研究

依托青岛红岛—胶南城际轨道交通工程侧穿多座桥梁的工程实例,采用有限元强度折减法,对上软下硬地层桩基近接影响下的隧道安全系数变化规律进行研究。结果表明:1)水平方向上,随水平净距增大,隧道安全系数增加,至1倍洞径后,安全系数趋于稳定;2)竖直方向上,随埋深增加,隧道安全系数表现为先增大后减小;3)桩基的存在将降低隧道安全系数,增加隧道达到最大安全系数所需的埋深。通过有无桩基对比,对不同相对位置关系下的地铁隧道近接桥梁施工影响程度进行判定:1)总体上竖向的影响范围和影响程度均大于横向;2)当隧道埋深位于桩底以上时,近接施工几乎只对隧道产生影响;3)当隧道埋深位于桩底以下时,近接施工对于隧道和桥梁桩基均有不同程度的影响,当隧道位于桩底时达到最大。通过样条函数插值补全和多重二次曲面拟合的方法,给出影响系数通用分区图,并结合数值模拟下的桩基受力变形特征,得出影响系数0.8对应的等值线为强影响区与弱影响区的分界线,影响系数1的等值线为弱影响区与无影响区的分界线。通过影响分区结论与监测数据对比,验证了研究成果的实用性。