轨道交通中线测设统一数学模型的建立   总被引：4，自引：0，他引：4  

吴浩  花向红  王新洲  周庆俊 《武汉大学学报(信息科学版)》2002,27(5):478-482

根据对常用的两种中线测设数学模型的分析，从线路中线曲率半径的特点出发，提出了中线整体积分数学模型，并导出其计算公式。为了实现整体积分模型的计算，对龙贝格积分算法进行了改进，并用于武汉市轨道交通一号线一期工程的中线测设。比较和分析表明，从实用性和精度等方面来说，整体积分模型是目前轨道交通最优的中线测设模型。  相似文献   

真空管磁浮列车T形槽轨平顺度检测方法研究及应用     

何勇  刘成龙  杨雪峰  段博凯 《测绘通报》2019,(6):117-120

针对T形槽轨平顺度的测量、分析与调整方法进行了研究,旨在解决T形槽轨建设中难以对其平顺度进行检测和分析的问题采用自由测站测量技术在管内构建高精度三维控制网.解决了因管内环境条件限制而难以建立测量基准的问题;基于此控制网,釆用自由设站测呈与极坐标测址法相结合的技术测得槽轨上各测点的三维坐标,为槽轨平顺度的分析提供了基础数据;为对槽轨平顺度质量进行判定,运用统计分析方法将槽轨上各测点的偏差悄况量化为4项统计指标.结果表明选用的4项指标能够定量和全面地反映槽轨平顺度质量;为提高槽轨平顺度,提出了基于槽轨上各测点的偏差计算调整量和据此对槽轨进行精调的方法.结果表明该方法能显著提高槽轨平顺度。  相似文献   

基于公交大数据的满载率推算方法 ——以深圳市为例     

闻帅  黄正东 《测绘通报》2019,(9):99-103

城市可持续发展需要提升公共交通的供给能力。公汽满载率是公交规划、调度和服务评价等方面的重要参数。在公交信息化水平不断提升的背景下,由公交IC卡数据和公共汽车GPS数据等构成的公交大数据为获得相对精确的客流提供了可能。虽然已有相对稳定的OD推算方法,但对于公汽满载率的研究尚不够充分。本文提出基于历史公交大数据的大规模公交出行链搜素算法,在此基础上构建公共汽车满载率数据库,并以深圳市为例揭示了高满载率线路段的时空分布特征。本文研究对于揭示公汽服务整体水平和探测关键公交廊道具有较大价值。  相似文献   

轨道交通典型隔振屏障隔振效果模型试验研究     

刘晶磊  张瑞恒  赵晓玉  刘恒  赵倩  王奥运 《地震工程与工程振动》2019,39(1):231-241

为了研究轨道交通中几种典型隔振屏障的隔振效果,本文通过室外模型试验,以振动加速度级作为振动评价标准,对其做出分析并给出相应评价。结果表明:(1)土体振动主要是由中低频振动波引起的;(2)对比分析几种典型连续隔振屏障的隔振效果:空沟>地下连续墙>碎石填充沟>橡胶填充沟;综合考察几种非连续隔振屏障得出:混凝土桩的隔振效果优于隔振井;隔振效果优劣比较为:混凝土实心桩>混凝土空心桩>PVC空井>碎石填充井>橡胶填充井;(3)对于单排混凝土空心桩,空心率越大,隔振效果相对越差;空心桩内部形状的改变对隔振效果影响不大,外部形状的改变对隔振效果有一定程度影响,但效果不显著,且桩体外截面为方形时的隔振效果较圆形差。  相似文献   

Bedrock geology controls on catchment storage,mixing, and release: A comparative analysis of 16 nested catchments          下载免费PDF全文

Laurent Pfister  Núria Martínez‐Carreras  Christophe Hissler  Julian Klaus  Gwenael E. Carrer  Mike K. Stewart  Jeffrey J. McDonnell 《水文研究》2017,31(10):1828-1845

The bedrock controls on catchment mixing, storage, and release have been actively studied in recent years. However, it has been difficult to find neighbouring catchments with sufficiently different and clean expressions of geology to do comparative analysis. Here, we present new data for 16 nested catchments (0.45 to 410 km²) in the Alzette River basin (Luxembourg) that span a range of clean and mixed expressions of schists, phyllites, sandstones, and quartzites to quantify the relationships between bedrock permeability and metrics of water storage and release. We examined 9 years' worth of precipitation and discharge data, and 6 years of fortnightly stable isotope data in streamflow, to explore how bedrock permeability controls (a) streamflow regime metrics, (b) catchment storage, and (c) isotope response and catchment mean transit time (MTT). We used annual and winter precipitation–run‐off ratios, as well as average summer and winter precipitation–run‐off ratios to characterise the streamflow regime in our 16 study catchments. Catchment storage was then used as a metric for catchment comparison. Water mixing potential of 11 catchments was quantified via the standard deviation in streamflow δD (σδD) and the amplitude ratio (A_S/A_P) of annual cycles of δ¹⁸O in streamflow and precipitation. Catchment MTT values were estimated via both stable isotope signature damping and hydraulic turnover calculations. In our 16 nested catchments, the variance in ratios of summer versus winter average run‐off was best explained by bedrock permeability. Whereas active storage (defined here as a measure of the observed maximum interannual variability in catchment storage) ranged from 107 to 373 mm, total catchment storage (defined as the maximum catchment storage connected to the stream network) extended up to ~1700 mm (±200 mm). Catchment bedrock permeability was strongly correlated with mixing proxies of σδD in streamflow and δ¹⁸O A_S/A_P ratios. Catchment MTT values ranged from 0.5 to 2 years, based on stable isotope signature damping, and from 0.5 to 10 years, based on hydraulic turnover.  相似文献   

Isotope-aided modelling of ecohydrologic fluxes and water ages under mixed land use in Central Europe: The 2018 drought and its recovery     

Aaron Smith  Doerthe Tetzlaff  Lukas Kleine  Marco P. Maneta  Chris Soulsby 《水文研究》2020,34(16):3406-3425

Understanding the interactions of vegetation and soil water under varying hydrological conditions is crucial to aid quantitative assessment of land-use sustainability for maintaining water supply for humans and plants. Isolating and estimating the volume and ages of water stored within different compartments of the critical zone, and the associated fluxes of evaporation, transpiration, and groundwater recharge, facilitates quantification of these soil–plant-water interactions and the response of ecohydrological fluxes to wet and dry periods. We used the tracer-aided ecohydrological model EcH₂O-iso to examine the response of water ages of soil water storage, groundwater recharge, evaporation, and root-uptake at a mixed land use site, in northeastern Germany during the drought of 2018 and in the following winter months. The approach applied uses a dynamic vegetation routine which constrains water use by ecological mechanisms. Two sites with regionally typical land-use types were investigated: a forested site with sandy soils and a deep rooting zone and a grassland site, with loamier soils and shallower rooting zone. This results in much younger water ages (<1 year) through the soil profile in the forest compared to the grass, coupled with younger groundwater recharge. The higher water use in the forest resulted in a more pronounced annual cycle of water ages compared to the more consistent water age in the loamier soil of the grasslands. The deeper rooting zone of the forested site also resulted in older root-uptake water usage relative to soil evaporation, while the grassland site root-uptake was similar to that of soil evaporation. Besides more dynamic water ages in the forest, replenishment of younger soil waters to soil storage was within 6 months following the drought (cf. >8 months in the grassland). The temporal evaluation of the responsiveness of soil and vegetation interactions in hydrologic extremes such as 2018 is essential to understand changes in hydrological processes and the resilience of the landscape to the longer and more severe summer droughts predicted under future climate change.  相似文献   

地铁对交通可达性的改善分析——以福州地铁前期线网为例     

孙朝锋  林西雁  陈晓毅  余明 《福建地理》2013,(4):87-92

在ArcGIS软件支持下,构建福州交通网络数据库,并结合多种数据和多种分析方法对福州地铁1、2号线路的交通进行了可达性评价．首先通过ArcGIS中的叠加分析、缓冲区分析、建模等手段对地铁沿线的道路网分布现状进行研究,发现地铁1、2号线建成后将大大缩短通行时间,提高了城市外围地区的交通可达性．其次,利用网络分析工具计算得出地铁将平均减少市民出行时间8．88min,减少地铁沿线出行时间11．6min,在出行高峰期的影响更为显著,可减少将近20min．研究结果可为交通部门提供参考．  相似文献   

基于InSAR的城市地下轨道交通沉降与灾害监测     

邱亚辉  别伟平  薄志毅  李长青  郑阔  郎博 《测绘通报》2020,(2):107-112

城市地铁建设会对邻域造成地质环境损伤,甚至发生灾变。传统基于点位测量的方法在实际应用过程中存在野外作业周期长、受天气影响及耗费大量人力物力等缺点。因此,本文基于城市地下轨道交通安全施工中的应用需求,以天津市地铁五号线为例,利用27景TerraSAR数据和PS-InSAR时序监测方法,对地下轨道交通地铁站和隧道施工影响进行了监测和评估。结果表明,PS-InSAR能在施工期间监测到地铁线及周边的形变,有利于城市轨道交通全生命健康监测。  相似文献   

水准测量技术在宁波市轨道交通3号线工程中的应用分析     

徐巍 《北京测绘》2020,(1):126-130

交通轨道施工环境复杂,周围高层建筑物林立,威胁着建设工程安全施工。因此,加强大型建设项目施工过程中的形变监测有助于施工项目安全开展。本文以水准测量技术为监测手段,对宁波市轨道交通3号线工程进行了形变监测,文章从3个方面进行形变分析。监测结果表明,深层土体位移最大为131.37 mm,支护桩顶部水平位移最大为2 mm,支护桩顶部沉降位移最大为2.1 mm,地表沉降最大为201.4 mm,项目施工开始至结束,未出现报警值情况,说明建设工程整体设计合理,认为该建设工程项目对临近建筑物影响不大,可以安全施工。  相似文献   

洛哌丁胺对大鼠慢传输型便秘模型的稳定性研究          下载免费PDF全文

黄亚娟  蒋士生  向燕芳 《应用海洋学学报》2020,36(7):153

目的：观察洛哌丁胺对大鼠慢传输型便秘模型稳定性的影响。方法：将20只大鼠随机分成对照组、模型组、模型维持组、治疗组,每组各5只。模型组、模型维持组、治疗组予洛哌丁胺混悬液灌胃,对照组以等体积的0.9%氯化钠注射液灌胃,连续6 d。造模第7天开始模型维持组继续予洛哌丁胺混悬液灌胃,治疗组灌胃莫沙必利混悬液,对照组及模型组灌胃等体积0.9%氯化钠注射液。观察大鼠造模前、造模6d和干预6d后的一般情况、6 h粪便粒数及重量、粪便含水率及大肠墨汁推进率。结果：造模6 d后大鼠出现活动减少,采食减少,毛发枯萎脱落,尿黄,大便数量及含水量减少;模型组造模停止6 d后及治疗组干预后大鼠一般情况改善,采食量、体质量增长,粪便粒数、粪便含水率均增加。各组大鼠6 h粪便粒数、重量、含水量方面,造模6d后,模型组、模型维持组、治疗组与对照组组间比较及造模前后组内比较,差异均有统计学意义（P<0.05）;对照组、模型组、治疗组与模型维持组比较,差异均有统计学意义P<0.05）;治疗组、模型维持组、模型组干预6d后与造模6d后比较,差异均有统计学意义（P<0.05）。对照组、模型组、治疗组与模型维持组大鼠大肠墨汁推进率比较,差异均有统计学意义（P＜0.05）。结论：洛哌丁胺大鼠慢传输型便秘模型是一种相对简便的慢传输型便秘大鼠模型,模型停药后可自愈,需用药物维持模型的稳定性。  相似文献