掘进机滚刀最优破岩刀间距的分析与计算

为进一步提高掘进机刀盘滚刀的破岩效率,在刀盘设计过程中确定合理的刀间距显得尤为重要。文章在利用岩石破碎角推导破岩刀间距范围的基础上,基于RFPA分析系统,进行了双刀、三刀作用下的不同刀间距破岩效果的分析,并推导出了最优破岩刀间距的计算公式;为验证刀间距计算公式的准确性,基于自主研制的滚刀岩机作用综合试验台,进行了三滚刀顺次滚压作用下的不同刀间距破岩效率的试验研究。试验结果验证了所推导的最优刀间距计算公式的科学性,进一步完善了刀盘刀具高效破岩理论。     

复合盾构刀具布置分析与研究

复合型盾构施工中,直接与岩土体接触的刀盘,其上刀具的布置是否合理直接影响盾构施工的顺利进行和施工成本。文章从复合盾构刀具布置的基本原则出发,指出了复合盾构滚刀刀间距的布置方式,利用等磨损原则分析了复合盾构刀具布置不同半径上每条轨迹应布置的刀具数量,阐述了不同刀具的螺旋曲线布置方法,并利用实例验证了利用该方法布置复合盾构刀具的合理性。     

预切槽刀具切削岩土介质特性研究

为了研究预切槽刀具对两种典型岩土介质的切削特性,文章采用颗粒离散元法建立刀具切削岩土介质的仿真模型,分析刀具切削两种不同岩土介质的动态过程、受力以及能耗变化等特性。研究结果表明:切削软土时易在刀刃前方发生堆积效应,受力发生在整个前刀刃上,而切削软岩时刀具受力几乎只发生在刀尖上;切削两种岩土介质时刀具所受水平力远大于其垂直力,切削软岩相比切削软土时受力波动更为剧烈,裂纹数目增长趋势也存在差异;随切深和刀前角改变两种岩土介质的破坏范围和破坏形式均发生转变;切削两种岩土介质的受力随切深增加而增加,随刀前角增加而减小,但对于软土,切深必须大到一定程度后刀前角对刀具受力才有显著影响,切深相比刀前角对刀具受力影响更大;切削两种岩土介质的切削比能耗随切深增加而减少,随刀前角增加也减少且减少幅度越来越大。     

全断面隧道掘进机锥面刀盘滚刀破岩机制研究

为揭示全断面隧道掘进机（TBM）锥面刀盘的滚刀破岩机制，明确滚刀安装排布对岩石破碎效果的影响规律，在对锥面刀盘多台阶悬切破岩模式分析的基础上，基于颗粒离散元方法构建锥面刀盘滚刀破岩数值模型并进行试验验证，开展锥面刀盘“平-锥”过渡区域滚刀破岩过程的数值模拟研究。研究结果表明：锥面刀盘锥区滚刀的破岩本质为临空面辅助破岩，破岩效果受到盘面锥角、滚刀间距、滚刀安装倾角的共同影响；为提高锥面刀盘破岩效率，可适当增大盘面锥角、减小锥区滚刀间距、增大滚刀安装倾角使锥区“斜刀正装”；对于抗压强度为180 MPa的极硬花岗岩，为确保高效破岩，建议盘面锥角为25°，锥区滚刀间距不大于70 mm，滚刀安装倾角与盘面锥角接近。     

行星刀盘方顶管全断面切削混凝土试验研究

目前盾构隧道联络通道主要采用土体加固暗挖法进行施工,但在复杂工况环境下仍存在极大施工风险。文章通过采用专门研制的行星刀盘方顶管对不同强度等级的混凝土试块进行全断面切削试验,对顶管刀具选型及布置、行星刀盘顶管切削性能等进行了研究,可为今后采用顶管法直接切削混凝土复合管片的盾构隧道联络通道的施工提供相应的技术储备,避免移除管片暴露加固土体,以大大降低盾构隧道联络通道施工风险。     

超大直径泥水平衡盾构断层破碎带掘进关键技术研究

为研究超大直径泥水平衡盾构穿越断层破碎带施工技术，以深圳某隧道工程为依托，对超大直径泥水平衡盾构穿越断层破碎带工程特点及难点进行分析，重点分析了泥水平衡盾构掘进过程中滞排、结泥饼、刀具磨损严重等问题产生的原因，并研究了泥水平衡盾构穿越断层破碎带的关键技术。针对滞排、结泥饼问题，在盾构机选型阶段优化刀盘结构设计，并采用大格栅+双破碎机排渣破碎系统、气垫直排式及主机段小循环模式等针对性措施，提高泥浆携渣能力、输送能力，降低渣土滞排和结泥饼的风险；针对刀具磨损严重问题，提出强化刀具状态监测及“逢红必检、有损必换”、杜绝刀具“带病作业”的刀具管理方针，确保刀具状态监测的可靠性和准确性，提高刀具使用寿命；最后，结合现场实践总结出“预防为主、防治结合、综合治理”的施工原则，采取辅助气压掘进模式穿越断层破碎带；通过对施工过程的研究分析，得到盾构掘进参数、泥水参数建议值以及各项针对性解决措施。     

复合地层盾构刀具磨损控制技术研究

文章以杭州地铁2号线杭发厂站—人民路站盾构区间隧道工程为背景,首先对盾构穿越上软下硬复合地层段的刀具磨损情况进行了分析,揭示了刀具严重磨损所导致的一系列施工异常现象,包括盾构掘进参数异常、盾构出土异常、地表严重沉降等;其次,针对盾构刀具非预见性严重磨损的工况,提出了地基加固结合常压换刀的处理方法,以及后续盾构掘进过程中土体改良、设备配置优化、参数控制等措施。结果表明,通过对复合地层的盾构施工措施进行优化,刀具磨损量控制在允许范围内。     

大直径泥水盾构刀盘刀具应用技术

长大隧道地质情况变化较大,盾构施工中刀盘刀具面临较多问题,尤其刀盘的磨损及刀具损坏是施工中经常遇到的一大难题,加强刀盘刀具技术管理成为大直径复杂地层泥水盾构施工管理的重要环节。文章以广深港客运专线狮子洋隧道盾构施工为例,从影响刀盘磨损及刀具损坏的原因分析至对刀盘的技术管理进行了分析研究,总结出了大直径复杂地层泥水盾构施工刀盘应用技术,对类似项目的盾构施工具有一定的借鉴和参考价值。     

土体力学参数随隧道施工动态变化对地层扰动影响的研究

文章基于土的三相体系,并依据隧道施工对土体扰动区域的划分,推导得出土体孔隙比与体应变的关系;运用有限元法计算不同区域的体应变,参考土体力学参数与孔隙比的关系,计算扰动土体力学参数在隧道开挖前后的变化,进而研究考虑土体力学参数变化与否对地层扰动的影响差异。计算实例分析表明:相对于假设隧道开挖过程中土体力学参数恒定的情况,在考虑土体力学参数改变情况下地表最大沉降增大8.1%,塑性区域范围面积增大55.6%。     

盾构机刀盘的地质适应性设计研究

为了提高盾构机的地质适应性,减少盾构施工过程中因地质因素造成的工程问题,盾构机刀盘必须根据地质条件进行地质适应性设计.文章基于多个盾构隧道施工实践,分析了国内外盾构隧道施工中出现的掘进困难、刀盘刀具快速磨损、结泥饼和开挖面失稳等工程问题,发现刀盘对岩土类型、岩土物理力学性质和水文地质条件不适应是产生这些工程问题的根本原因.基于岩土体与刀盘相互作用的机理和盾构施工经验,文章分别总结了刀盘结构、刀具选型布置和刀盘碴土改良装置在地质适应性方面的设计经验.     

Analysis of factors affecting the choice of route of pedestrians

Pedestrians as compared to vehicular traffic enjoy a high degree freedom of movement even in heavily congested areas. Consequently, there are more alternative links available to pedestrians between a given origin‐destination (O‐D) pair. This paper describes a study done by the University of Calgary to evaluate the factors affecting the choice of route on intra‐CBD trips or trips within the Central Business District (CBD).

An origin destination survey conducted in downtown Calgary, Alberta enabled the identification of the most significant factors influencing the choice. These factors were analyzed in relation to the physical characteristics of the location, personal characteristics of the trip maker and the type of the trip.

It appears that most people chose the shortest link and factors such as the level of congestion, safety or visual attractions were only secondary. This suggests that the length should be made a major consideration when planning and designing pedestrian links.     

实现多组态计量软件集中监控的可行性分析

天然气自动计量系统有多种组态软件,由于软件的不相通性,造成了计量系统数据采集的通用性差、数据传输与入库的时效性差、数据利用的可靠性低.结合各组态软件的实际情况,从设计上充分利用Oracle大数据处理能力以及Partition(分区表)的特性,实现历史数据的存储,应用WebService与COM+数据访问组件提供多层数据访问架构,采用OPC与DDE工业数据交换协议,实现了各站场计量数据的实时上传,为连续数据采集和实时监控提供了可能,节约了改造成本.     

注汽管道承压能力评估和实物试验验证

基于失效评估图技术对某注汽管道进行了承压能力评价,给出了管线在不同腐蚀壁厚情况下的极限承压能力和极限裂纹尺寸。并利用实物爆破试验验证了评价方法的安全性和有效性,通过对爆破断口进行宏观和微观分析,发现管段的开裂属于脆性开裂。     

Direct analysis of the perceived importance of attributes of reliability of travel modes in urban travel

Reliability of travel modes was found to be the most important characteristic of transportation systems in several attitudinal investigations of individual travel behavior. This paper represents the first part of a research effort aimed at gaining a better understanding of the characteristics of reliability of transportation modes in urban travel. In this research, reliability characteristics are identified; their importance relative to each other is assessed, and an insight into possible structure of an objective reliability index is discussed. The research is based on perceived values of reliability, which were identified through a large attitudinal survey conducted in the Chicago metropolitan area.     

盾构隧道管片接头抗剪力学性能研究

通过对南京长江盾构隧道环向管片接头进行的三组原型抗剪(无螺栓剪切、有螺栓逆剪和有螺栓顺剪)加载试验,分析研究了管片接头在剪力作用下的受力、变形和破坏特征,给出了管片接头混凝土接触面的静摩擦系数,得到了接头剪力主要由混凝土接触面承担、破坏形式为连接斜螺栓剪切延性破坏的结论。通过对管片结构的有限元数值模拟计算得出:接头处的剪力与轴力比小于接缝面的摩擦系数,管片不会发生相互错动,结构是稳定的。     

管道施工组织设计

在管道工程建设中，管道施工组织设计是一项重要的经济管理性文件，也是验证施工企业在工程建设中具有的施工实力和管理水平的综合技术能力体现。它对工程建设项目施工全过程活动的质量、进度、技术、安全、经济和管理组织起着不可估量的重要作用。     

Non-parametric analyses of efficiency of airports

This paper estimates the efficiencies and productivity changes of 12 international airports in the Asia-Pacific region based on data from 1998 to 2006. We apply stochastic frontier analysis (SFA) to compute efficiency estimates and use the Malmquist productivity index (MPI) to analyze productivity changes. We use the SFA model with a translog-type production function after testing the statistical hypotheses. According to the results of the SFA hypothesis tests, airports have experienced a technological regression; the deviations from the efficiency frontier are caused more by technical inefficiency than random noise. However, the inefficiency was found to decrease. The MPI reveals a declining trend resulting more from technological change than from efficiency change, with a decrease in inefficiency. Taken together, both the hypothesis tests and the MPI not only provide consistent conclusions, but also suggest that airports should concentrate on technological progress.     

波纹管应力分析研究进展

评述了波纹管应力理论研究方法的进展情况，围绕解析法、工程近似法和数值法，对波纹管理论研究中的一些主要成果作了较详细的回顾和总结，对各种研究方法作出了评价，展望了亟待解决的一些问题。     

Evaluation of pedestrian crosswalk level of service (LOS) in perspective of type of land-use

In India pedestrians usually cross the road at mid-block crosswalks due to ease of access to their destination or the development of adjacent land use types such as shopping, business areas, school and residential areas. The behaviour of pedestrian will change with respect to different land use type and this change in behaviour of pedestrian further reflects change in perceived level of service (LOS). So, it is important to evaluate the quality of service of such crossing facilities with respect to different land-use type under mixed traffic conditions. In this framework, pedestrian perceived LOS were collected with respect to different land-use type such as shopping, residential and business areas. The ordered probit (OP) model was developed by using NLOGIT software package, with number of vehicles encountered, road crossing difficulty as well as safety considered as primary factors along with pedestrian individual factors (gender and age), land-use type and roadway geometry. From the model results, it has been concluded that perceived safety, crossing difficulty, land-use condition, number of vehicles encountered, median width and number of lanes have significant effect on pedestrian perceived LOS at unprotected (un-signalized) mid-block crosswalks in mixed traffic scenario. The inferences of these results highlights the importance of land use planning in designing a new set of pedestrian access facilities for unprotected mid-block crosswalks under mixed traffic conditions. Also the study results would be useful for evaluating pedestrian accessibility taking into account different land-use type and planning required degree of segregation with vehicular movement at unprotected mid-block crosswalk locations.     

埋地管道防腐保温层失效评价

明确埋地管道防腐保温层的技术评价标准,对埋地钢质管道的安全运行,延长管道使用寿命具有重要意义。为了对埋地管道防腐保温层做出有效评价,从间接检测与开挖检测2个方面,结合现场检测数据,提出了基于防腐保温层的电流衰减率、绝缘电阻率、质量状况与厚度的分级评价标准及基于4种评价指标的综合评判方法。工程实践表明,该评价标准对防腐保温层是否存在失效能做出有效判断。