Discussion on Structural Health Monitoring of Urban Underground Road Tunnel

The number of urban underground road tunnels in China is increasing year by year,and health monitoring of tunnels is an effective management method to ensure their structural integrity.However,for shorter underground road tunnel projects,insufficient investment often leads to less frequent application of health monitoring systems.The application of intelligent structural health monitoring means can not only reduce the project cost but also help workers fully understand the actual situation of the tunnel structure.Therefore,this paper analyzes the characteristics,problems,and design of the urban underground road tunnel structural health monitoring system,and discusses the implementation of the urban underground road tunnel structural health monitoring system.

Drivers'fixation transfer characteristics in urban tunnels

To improve the safety performance of urban tunnels,the fixation transfer characteristics of drivers with different driving experience levels in urban tunnels were investigated.First,a real vehicle test was performed in an urban tunnel,and the eye movement data of 10 drivers with different driving experience levels were collected using a Dikablis eye-tracking system.Second,the driver fixation range was divided into eight areas of visual interest by using the K-means clustering method,and the fixations in different sections of the tunnel were comparatively analyzed.Finally,on the basis of the divided areas of visual interest,fixation transfer rules and the stationary distribution characteristics of drivers with different driving experience levels on different sections of the tunnel were discussed using Markov theory.Results indicate that drivers'probability of repeated fixation is greater and that the efficiency of visual search is lower at internal sections of tunnels than in external sections.Drivers obtain information mainly from the straight upper front and straight lower front areas,and the probabilities of fixation points in these two areas at the threshold and exit sections are significantly higher than those in other sections.Relative to experienced drivers,novice drivers allocate little attention to the straight upper front area and rear-view mirrors.Hence,they have weak fixation when looking forward,and they lack experience in obtaining information on rear-approaching vehicles and controlling speed.

Tunnelling performance prediction of cantilever boring machine in sedimentary hard-rock tunnel using deep belief network

Evaluating the adaptability of cantilever boring machine(CBM) through in-depth excavation and analysis of tunnel excavation data and rock mass parameters is the premise of mechanical design and efficient excavation in the field of underground space engineering.This paper presented a case study of tunnelling performance prediction method of CBM in sedimentary hard-rock tunnel of Karst landform type by using tunneling data and surrounding rock parameters.The uniaxial compressive strength(UCS),rock integrity factor(Kv),basic quality index([BQ]),rock quality index RQD,brazilian tensile strength(BTS) and brittleness index(BI) were introduced to construct a performance prediction database based on the hard-rock tunnel of Guiyang Metro Line 1 and Line 3,and then established the performance prediction model of cantilever boring machine.Then the deep belief network(DBN) was introduced into the performance prediction model,and the reliability of performance prediction model was verified by combining with engineering data.The study showed that the influence degree of surrounding rock parameters on the tunneling performance of the cantilever boring machine is UCS > [BQ] > BTS >RQD > Kv > BI.The performance prediction model shows that the instantaneous cutting rate(ICR) has a good correlation with the surrounding rock parameters,and the predicting model accuracy is related to the reliability of construction data.The prediction of limestone and dolomite sections of Line 3 based on the DBN performance prediction model shows that the measured ICR and predicted ICR is consistent and the built performance prediction model is reliable.The research results have theoretical reference significance for the applicability analysis and mechanical selection of cantilever boring machine for hard rock tunnel.

Effects of Urban Morphology Changes on Ventilation： Studies in Wind Tunnel

This paper presents study of the effects of urban morphology changes on ventilation dynamics through a comparative study between blocks of Copacabana and Ipanema neighborhoods, located in Rio de Janciro City, Brazil. The study was developed with the aid of experimental simulations in a wind tunnel, taking into account the urban morphology and its relations to open spaces. A diagnosis was produced through the exam of the wind effects in relation to the volume of built and non-built spaces. The effects were classified as positive or negative, in relation to the tropical climate. At first, both blocks studied, one in Ipanema and one in Copacabana, were selected according to common characteristics, which establish a relation between the two regions, such as the distance to the beach and the presence of a public square. The results confirmed our expectations showing Ipanema as a more ventilated area.

Research on Deformation Control Indicators and Standard of Urban Traffic Tunnel Construction Adjacent to High-rise Building

The biggest environmental problem caused by the construction of tunnels adjacent to high-rise buildings is the settlement of buildings.The paper analyzes the influence of tunnel excavation on the deformation of the superstructure and the deformation mode of the superstructure.It introduces the indicators and standards for the construction control of tunnel adjacent to the building at home and abroad.Combined with the Yuzhong tunnel project under construction in Chongqing,the main monitoring indicators and control standards of the Yuzhong Tunnel passing through the main buildings are given after comprehensive analysis and considerations,which provide a reference for the deformation control indicators of similar urban traffic tunnels adjacent to high-rise buildings.

Simulation Analysis of CO Concentration Distribution in Beijing Yuntong Tunnel

In this paper, the concentration distribution of CO emitted by motor vehicles in Beijing Yuntong Tunnel is simulated and analyzed based on Fluent numerical simulation software. Firstly, the physical model of tunnel geometry is established. Secondly, the suitable control equations and boundary conditions are selected to describe the diffusion distribution of pollutants in the tunnel. At the same time, the reliability of the model is verified according to the measured data, and the distribution law of CO concentration in the tunnel is observed through the simulation results. The tunnel is unorganized at the entrance of the tunnel. In the simulation results, the CO concentration at the entrance of the tunnel is far more than the CO unorganized emission limit in Beijing. The CO emission of the tunnel should be purified to prevent pollution of the urban environment.

极端环境隧道建造面临的主要问题及发展趋势

聚焦艰险山区、深水海域与城市敏感区3类极端环境,全面梳理和总结了在此环境下隧道建造面临的主要问题、相关技术突破和未来发展趋势。针对艰险山区中极高地应力、高地温、高海拔以及活动断裂带等极端条件,总结分析围岩和隧道的变形机制、破坏机制及防护措施,并指出未来可通过大数据、机器学习等手段建立更精准的预测模型,以实现隧道建造过程的实时监控和风险评估;针对深水海域中高水压、高烈度地震、强侵蚀环境等极端条件,分析多因素耦合下沉管法及盾构法隧道管片及接头的劣损和破坏机制,总结提升其力学和耐久性能的主要技术措施,并提出未来仍需针对海底隧道管片接头的防水、抗震及抗侵蚀性能开展更深入的研究,以形成完整的理论和技术体系;针对城市敏感区隧道穿越既有隧道、敏感建构筑物、地下障碍物等挑战,总结分析盾构法和顶管法施工环境响应规律、地层变形评估方法和控制技术措施,提出未来可采用机器学习等技术辅助隧道建设,以提升预测和控制的准确性,减小建设过程对城市环境的扰动。目前,相关研究成果为极端环境下的隧道工程建设提供了重要支撑,但部分技术仍需进一步在实践中完善并形成规范,以指导后续的工程建设;而随着新一代信息技术的发展,未来隧道建造必将朝着数字化、智能化、自动化的方向发展,从而保障极端环境下隧道建设的安全、绿色、高效。

城市交通隧道电动汽车火灾安全研究进展

城市电动汽车数量增加给城市交通隧道消防安全带来了新的挑战。论文首先归纳了隧道内电动车辆火灾研究的科学问题和关键技术问题,总结了电动汽车火灾成因及研究手段、火灾燃烧热特性、燃烧产物特性等领域的研究成果,分析了隧道狭长受限空间结构对电动汽车火灾发展过程的影响,探讨了城市交通隧道电动汽车火灾的消防救援。根据现行消防标准规范及隧道消防设计指南,讨论了应对电动汽车火灾交通隧道消防系统设计需要改进的要点。研究表明,新能源车火灾场景比燃油车火灾场景更复杂,主要表现在电池不稳定的喷射火源、持续时间、峰值热释放和峰值温度、汽车带电风险等方面。目前电动汽车火灾实体试验研究主要是在大空间或者开放空间中进行,隧道受限空间对电池燃烧特性影响、电动汽车火灾羽流特性以及有毒烟气蔓延及控制还缺乏系统性研究。研究成果能够为城市交通隧道的消防设计、安全运营以及应急救援预案制定提供参考。

城市轨道交通超长隧道双车追踪模式下火灾烟气控制与人员安全疏散研究

[目的]城市轨道交通发车间隔一般较短,在超长隧道内会出现同方向行驶两列列车的情况,一旦发生火灾容易造成重大财产损失和人员伤亡,因此需对超长隧道双车追踪模式下的火灾烟气蔓延规律和人员安全疏散策略进行研究。[方法]采用FDS(火灾动力学模拟)软件和Path-finder软件,建立超长隧道火灾模型和人员安全疏散模型,对双车追踪模式下的火灾烟气蔓延规律,以及人员疏散进行仿真分析。[结果及结论]双车追踪模式下,前车尾部着火,通过临界风速纵向通风可保证前车火灾安全;火源下游烟气前锋的蔓延速度为3.20 m/s,至600 s时烟气蔓延至后车,620 s时烟气可完全覆盖后车;烟气温度沿隧道纵向衰减很快,且温度衰减符合双指数模型规律。双车追踪模式下,减小联络通道间距可减少人员疏散总时间,对人员疏散时离开列车的时间影响不大;开启列车端门和疏散平台一侧车门,可显著减少人员疏散时间。在超长隧道双车追踪的最不利火灾场景下,人员疏散存在困难,可通过减小联络通道间距保障人员疏散安全。

城市浅埋隧道自然排烟竖井临界间距研究

竖井间距会改变竖井内外压差,当竖井内外压差为0时,隧道火灾烟气将无法排出,此时竖井对应位置为竖井临界间距。由竖井内外口压差理论分析,给出竖井临界间距理论模型,再采用FDS模拟进行仿真验证。结果表明:设置竖井可明显降低隧道温度,竖井间距为临界间距时,温度下降幅度接近150℃,人员疏散路径温度低于60℃,竖井排烟效率在55%~80%,可有效进行竖井排烟;当竖井间距大于竖井临界间距时,隧道内烟气压强小于竖井出口处风压,竖井排烟效率低于50%。

城市连续隧道交织区主线交织车辆换道点选择行为研究

基于城市连续隧道交织区分析主线交织车辆换道点选择行为,以实地采集的车行轨迹数据为基础,利用随机森林模型分析主线车辆换道点选择行为特征及影响行为决策的影响因素,而后分别采用支持向量机模型与随机森林模型进行换道点选择行为决策建模和对比分析。研究结果表明:影响主线交织车辆换道点选择的主要因素为目标车辆状态以及本车道的后车状态,且经特征筛选之后建立换道决策模型的精度更高,其中支持向量机模型可以较好的刻画换道行为,模型的预测精度不低于85%。研究成果有助于在仿真模型中更准确描述换道点选择行为,同时为城市连续隧道交织区的优化和辅助驾驶策略制定提供支撑。

广州城市快捷路二期过江通道总体设计

广州城市快捷路二期是广州中心城区内外环之间的辅助环形连续交通道路,同时也是白鹅潭地区“三环七射”道路骨架系统的三环之一,过江通道两岸具有接线路网复杂、沿线城中村及建设地块密集等特点,总体设计难度大。详述了过江通道建设的意义,综合考虑总体规划、城中村改造计划、征地拆迁、环境效应和江中通航要求等因素,先进行线位比选,然后进行过江桥隧方案比选,最后通过隧道工法比选,对过江通道总体设计做了细致的分析比对,最终选取了过江沉管隧道作为实施方案。该项目对缓解城市交通压力和加速项目沿线经济快速发展具有重要意义,同时也为沉管隧道建设进一步积累经验。

城轨项目基坑施工对综合管廊盾构井的影响分析

本文以广州市天河智慧城科韵路段综合管廊K4井为研究对象,进行临近城轨项目基坑施工对综合管廊盾构井的影响分析。利用岩土工程专用软件Midas/GTS进行有限元模拟,通过对关键施工步骤的数据统计,分析了临近基坑开挖对K4井地层位移、地连墙位移、内支撑轴力的变化及其影响规律,并提出了合理的建议和措施,保证了基坑的安全施工。

基准排放因子更新对隧道需风量的影响研究

为解决交通车辆持续更新导致的城市隧道内通风系统设计浪费和运营闲置,研究基准排放因子更新对隧道需风量的影响,并建立2种应对车辆更新的基准排放因子计算方法.首先,通过理论分析明确需风量计算式中随时间更新的关键参数为基准排放因子;随后,根据定量分析得到基准排放因子和纵坡-车速系数更新对需风量的影响;最后,结合国外理念和实际设计经验,提出2种考虑时间更新的基准排放因子计算方法.研究结果表明:我国道路隧道通风设计规范在制定基准排放因子时参考了世界道路协会(PIARC)通风报告,并分析得到了参考理由;与2000年相比,2021年的CO、NOx和PM基准排放限值分别降低了81.6%、76.7%和97.9%;建立了使用机动车污染物排放限值作为基准排放因子的最不利设计方法,计算出2018年各污染物基准排放因子(CO为0.0011 m^(3)/(辆·km),PM为0.4610 m^(2)/(辆·km)),相比于2014年《细则》分别降低84.3%和77.0%.建立并验证了基准排放因子计算方法,为城市道路隧道通风系统设计提供参考.

浅埋矩形顶管施工对临近管线与地表的影响研究

矩形顶管施工引起的地表变形特征与圆形顶管或盾构隧道存在显著差异。为了明确浅埋矩形顶管施工过程中的地表沉降特征以及顶管施工对下方既有盾构隧道的影响,根据现场矩形顶管施工监测结果,分析矩形顶管施工过程中地表的变形规律,以及顶管下方既有盾构隧道的变形情况。传统的Peck公式适用于圆形顶管或圆形盾构隧道,因此采用改进的Peck公式来描述矩形顶管引起的地表变形特征;根据现场监测分析顶管施工引起的地表变形、管线变形和下卧隧道沉降规律。研究表明:改进的Peck公式相比于传统的Peck公式可以准确描述矩形顶管施工引起的地表变形规律;顶管施工引起地表和上方管线的沉降规律是一致的,但与下卧隧道的变形规律存在显著差别。

武汉长大隧道污染物浓度特征及净化系统效果验证

基于城市隧道因受规划、景观、用地等限制,无法任意设置高空排风塔集中排放隧道汽车尾气,为了解决城市隧道汽车尾气污染物问题,研究隧道废气就地净化技术应用于城市隧道工程的适用性。以武汉长江隧道为研究对象,利用污染物实时在线监测仪器,如颗粒物分析仪、氮氧化物分析仪以及一氧化碳分析仪,监测隧道内汽车尾气主要污染物,得出污染物浓度特征,PM_(2.5)的日均质量浓度为257.04 g/m^(3),PM10的日均质量浓度为287.53 g/m^(3),NO_(2)的日均质量浓度为109.02 g/m^(3),均超过《环境空气质量标准》(GB 3095—2012)及其修改清单中的二级标准。结合隧道工程区域环境空气质量规划和隧道结构特征,设计城市隧道空气净化系统的技术方案并验证其净化效果。

老旧城区微型管廊的设计创新与实践研究

为解决微型管廊渗水积水、检修困难和施工空间受限等问题,推动微型管廊在老旧城区的广泛应用,通过分析,创新性地在微型管廊盖板间设置榫卯结构和加设胶质薄膜,解决盖板渗水问题;在微型管廊底部设计排水与管线出线空腔,解决微型管廊积水问题;通过设计平躺式检修系统(包括导轨、可升降滑动检修床等),解决因微型管廊空间狭小引起的检修困难问题;通过设置混凝土衬墙和取消基坑肥槽以最大限度减小微型管廊施工所占空间。最后,以多宝路历史文化街区市政基础设施提升工程项目为例,介绍2条街巷微型管廊设计的总体理念、技术手段和实施方法。研究表明:在微型管廊底部设置排水与管线出线空腔,不仅可以更集约化地布管及保证管廊不积水,而且能避免管线在微型管廊顶部出线造成的检修困难;微型灌注桩+内撑+衬墙的组合方式可以满足施工场地受限情况下的施工需求,且基本不影响两侧现有建筑的安全。

我国城市地下空间盾构法隧道工程技术新进展

基于盾构施工特点,对盾构法施工技术的发展过程和创新进展进行调查研究,总结盾构法施工技术在地铁、市政公路、城市铁路、城市水工隧洞、城市综合管廊等工程中的最新应用,阐述城市盾构法隧道在地质条件多样化、越江跨海常态化、结构断面多元化、地面条件复杂化、隧道结构耐久性等方面面临的技术挑战。介绍超大直径盾构装备、大直径泥水盾构常压换刀、多模盾构、类矩形盾构隧道建造、联络通道机械法施工、软硬极端悬殊地层掘进、富水砂卵石地层土压平衡盾构、地下高地震烈度盾构隧道减隔震抗震和超长距离综合施工等技术创新成果;总结不良地质识别、设备状态实时感知、同步推拼连续掘进、盾构自动驾驶技术、盾构智能化管控平台等盾构智能掘进技术进展;指出城市地下空间建设盾构法隧道工程的发展趋势,地铁隧道、城市道路、综合管廊、城市给排水等设施需要不断更新,并网络化,盾构法隧道技术需要不断发展,盾构法隧道智能化施工需日趋精益。未来盾构装备将朝着“多模式、无刀化、外星化”等多元化,多源信息感知、管片智能拼装、地质探测预报、自主感知掘进决策等智能化以及特大直径、超长距离、超大埋深、超高水压等方向发展。

城市道路隧道晚高峰环境参数时空差异性分析

隧道内晚高峰的出现会导致交通流量的时空分布发生很大的变化,并进一步影响隧道内的环境参数及CO浓度。为了改善隧道内环境质量,研究人员于晚高峰时段对玉涵路隧道内空气温度、风速、CO浓度、CO_(2)浓度和颗粒物浓度进行了详细的现场实测。测试结果表明:节假日的交通晚高峰时长更短以及高峰车流量更低,从而引起节假日的风速、温升、CO_(2)增量较工作日平稳且状况更优;工作日洞内风速减小1.7~3.2 m/s,纵向温升为6.1~7.7℃;随着车辆行驶速度延迟时间的增大,风速、温升、CO_(2)增量延迟时间呈增大趋势,最大延迟时间可达70 min;工作日隧道通风应考虑交通高峰开始后20 min至交通高峰结束后70 min时间段的延迟时间。

西安地铁6号线某隧道穿越地裂缝带设防措施研究

[目的]西安地铁6号线二期工程某隧道沿线分布有7条地裂缝,工程性质较差,施工时可能会造成隧道局部坍塌,以及基底不均匀沉降,从而加剧地裂缝活动,严重威胁城市轨道交通的建设和运营。因此,有必要对6号线某隧道穿越地裂缝带进行设防研究。[方法]基于对与西安地铁6号线二期工程相交的各条地裂缝历史活动特性分析,对各条地裂缝对地铁影响程度分级进行定性评价。综合该分级定性评价结果,隧道与地裂缝的空间相对关系,以及地裂缝在百年使用期内最大垂直位移量设计建议值,对地裂缝垂直、水平及轴向位移量,以及隧道结构纵向设防长度进行了估算。依据二类地裂缝场地的工程防治原则,针对隧道穿越地裂缝带提出相应设防措施。[结果及结论]6号线某隧道穿越地裂缝带的设防措施为:隧道衬砌结构采取分段设缝,扩大隧道断面净空及局部衬砌加强,接缝处采用柔性接头。该设防措施目前已经成功保障了7条地铁线路的安全施工与运营。