共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
瓦斯隧道通风控制系统是利用自动瓦斯监测系统对隧道内施工环境进行监测和对通风设备运行状态进行控制,在实时检测隧道内CH4、CO、风速、温度等参数的基础上,将这些数据传送到地面监控室的计算机,计算机再以检测到的环境参数为依据,对瓦斯隧道内通风状况进行动态分析与预警,为实时掌握瓦斯隧道通风安全状况提供技术手段,提高瓦斯隧道施工通风的管理水平,从而保证隧道施工安全有效地进行.文章以兰渝铁路梅岭关隧道为例,介绍了瓦斯隧道的施工通风方案、通风系统检测、通风安全预警以及瓦斯监测系统的的现场应用. 相似文献
3.
4.
板桃隧道出口岩溶段桩基托梁施工 总被引:1,自引:0,他引:1
文章简要介绍渝怀铁路板桃隧道出口DK215+693~+759段溶洞、暗河整治中桩基托梁的施工技术,可为今后类似工程的设计和施工提供依据. 相似文献
5.
昆仑山隧道在衬砌完成后,多处发生渗水现象.根据实地调查,隧道内最主要的出水点主要集中在3个地段DK976+283右侧避车洞、DK976+793左侧避车洞和DK977+573左侧避车洞.根据隧道内出水严重程度、地表示踪剂投放条件,以及水害治理的紧迫性,分3个阶段进行昆仑山隧道渗漏水连通试验.试验研究认为,因施工扰动局部改变了隧道穿越区域多年冻土的水-盐循环条件和水流场,并对隧道穿越区域的温度场造成较大的影响,以至于隧道内渗(涌)水与地表水之间,以及隧道衬砌背后与破碎围岩之间的地下水连通,造成隧道内多处发生渗(涌)水的现象.文章还针对性地提出了水害整治建议. 相似文献
6.
宜万铁路野三关隧道602溶腔处治 总被引:1,自引:0,他引:1
文章主要介绍宜万铁路野三关隧道DK124+602高压富水溶腔的规模与处治技术.602溶腔影响隧道纵向达20 m,向上与3号暗河连通,最大涌水量48万m3/d,实测水压1.0 MPa.该溶腔段施工采取了高位排水降压、帷幕注浆、管棚预支护等技术措施,实现了降压、加固、堵水、肪渗的目的,防止高压渗水直接传递给隧道结构,为隧道开挖通过溶腔及运营结构安全提供了重要保障. 相似文献
7.
8.
铁路隧道穿越岩溶群区施工控制技术研究 总被引:1,自引:0,他引:1
文章以渝(重庆)怀(怀化)铁路板桃隧道为工程背景,阐述了该隧道穿越DK215+650~DK216+105段岩溶群区的施工技术.为确保施工工期,施工中采取了"先绕行后处理"的原则,设置施工迂回导洞绕行岩溶区,并通过横通道与正线相连.针对岩溶区内不同的溶洞类型分别采取跨越、支顶、锚喷支护、浆砌片石回填等技术措施,同时根据暗河与溶洞内的水流大小及流向采取了诸如涵洞、小桥等设施或开凿泄水洞将水排出洞外,安全稳妥地通过了455 m岩溶群区.本工程取得的经验可供类似工程施工中借鉴. 相似文献
9.
10.
铁路隧道施工阶段监控量测是保障信息化施工的重要手段,目前关于隧道监控量测项目及内容主要通过围岩级别定性判定,未建立统一的定量化评价体系。基于风险分析理论,依据隧道发生风险概率指数与风险后果指数,建立铁路隧道施工阶段监测等级及划分方法。将未确知测度理论作为风险概率指数评价方法,选取岩石风化程度、岩石质量指标和单轴饱和抗压强度等8个影响指标,构建指标测度函数,结合改进层次分析法对各评价指标进行赋权,依照置信度识别准则判定风险概率指数,定量计算监测等级指数确定监控量测等级及相应的监测内容。以渝昆铁路小草坝隧道为例,对该隧道3个里程区段进行施工阶段监测等级划分,评价结果显示DK344+200~DK344+220区段监测等级为C。 相似文献
11.
12.
Ingmar Andrasson 《先进运输杂志》1998,32(1):23-34
A survey of research and development in advanced transit has been made by Chalmers University of Technology in Gothenburg in cooperation with Trans21 in Boston. Summary findings are reported for fourteen academic research programs and ten development programs for PRT. An earlier version of this paper was presented at the International Conference of PRT and other Emerging Systems held in Minneapolis in 1996. 相似文献
13.
管道风险分析指数评分法中重要步骤之一就是确定影响管道事故因素的权重,各个管道风险因素在整个管道事故中所占的权重是不相同的。针对目前管道风险分析指数评分法基本假设之一(各因素的分值范围都是0~100分),为了更加客观、准确、合理地反映各个风险因素对于管道事故的影响程度,提出并论述了依据层次分析法的数学逻辑性进行综合计算得出管道风险因素的权重,然后对评分法中各个因素的最高分值,根据其权重不同进行相应调整,从而增强评价者对风险因素的认识和评判能力,提高管道风险评价结果的准确性。 相似文献
14.
The concept of accessibility has acquired numerous meanings along multiple dimensions during the century of its evolution. This essay argues for the salience of two dimensions: application-based and definition-based. In its application, accessibility has incorporated positive and normative dimensions which have varied in prominence over time. In its definition, accessibility has varied between a mode of evaluation incorporating measured mobility and proximity, on the one hand, and a predefined market basket of urbanist improvements to transportation and land use systems, on the other. Advocates of the accessibility shift should emphasize both the measured approach to accessibility and accessibility’s normative side. 相似文献
15.
16.
17.
Nicholas B. Taylor 《运输规划与技术》2018,41(1):37-57
ABSTRACTPredicting the risk of traffic demands and delays exceeding critical limits at road junctions, airports, hospitals, etc., requires knowing how both mean and variance of queue size vary over time. Microscopic simulation can explore variability but is computationally demanding and gives only sample results. A computationally efficient approximation to the mean is used in many modelling tools, but only empirical extensions for variance in particular situations have been available. The paper derives theoretical formulae for time-dependent and equilibrium variance, believed to be novel and to apply generally to queues covered by the Pollaczek–Khinchin mean formula, and offering possible structural insights. These are applied in an extended approximation giving mutually consistent mean and variance estimates with improved accuracy. Tests on oversaturated peak demand cases are compared with Markov probabilistic simulation, demonstrating accuracy (R2?>?0.99) for typical random, priority-like (M/M/1) and traffic-signal-like (M/D/1) queues. Implications for risk analysis, planning and policy are considered. 相似文献
18.
The big paradigm for cities nowadays is to study the movement of pedestrians at the interface between metro and bus systems – metro–bus interchanges. When these interchanges are not well designed, walking is inefficient and can be unsafe for pedestrians. This paper analyses, by means of a pedestrian microsimulation model, metro–bus interchange spaces in order to propose planning guidelines for the city of Santiago de Chile. Specific objectives are (1) to identify the variables that provide efficiency and safety in those spaces; (2) to simulate different scenarios using the pedestrian simulation model LEGION; (3) to propose planning and design guidelines for pedestrian spaces at metro–bus interchanges; and (4) to contrast the recommendations in the recently opened terminal station on Line 1 of Metro de Santiago: Los Dominicos Station. 相似文献
19.
20.
在公路沥青混凝土路面配合比设计中,矿料配合比设计是一个重要环节。研究发现,通过使用计算机和Excel软件,在各种表格的单元格中设置相应计算公式、宏和绘图步骤,输入各种配合矿料的累计通过百分率后,通过简单的人机对话,完成各种矿料百分含量数据的输入和调整,自动生成各种图表;在质量监督中,通过现场检测混合矿料的级配,输入现场矿料、水泥混合累计通过百分率可自动判定其级配是否合格。 相似文献