With the acceleration of the construction of a strong transportation country,the multi-modal transportation"data brain"has become an important engine driving and leading the high-quality development of the transportation industry.However,there is currently no consensus in the academic community on the definition and connotation of the"data brain"in comprehensive transportation,and its functional positioning and service boundaries have not been systematically and comprehensively studied.Based on a systematic review of literature on intelligent transportation systems,in the paper,the definition and connotation of the"data brain"in comprehensive transportation are proposed,the basic characteristics of"comprehensive perception,spatiotemporal interaction,intelligent deduction,and iterative evolution"are analyzed,and a comparative analysis perspective is used to explore the service boundaries of the"data brain"in comprehensive transportation.The functional positioning of the"data brain"in comprehensive transportation is clarified from multiple dimensions such as biomimetic simulation,scenario application,sustainability,and social responsibility,aiming to provide theoretical support for the joint construction of the"data brain"in multi-modal transportation across the country,and fully leverage the amplification,superposition,and multiplication effects of comprehensive transportation data elements.
In order to solve the adverse effects of hidden landslide disasters in densely vegetated mountainous areas on the whole life cycle of expressways,by taking advantage of the characteristics of airborne LiDAR to penetrate vegetation,a high-precision DEM with a spatial resolution of 0.2 m is obtained for the highway under construction in the G0321 Qimen to Anhui-Jiangxi boundary section(K2+430～K14+750),a remote sensing interpretation method suitable for dense vegetation mountainous areas is prepared,a sample database of landslide disasters in the study area is established,and the accuracy of remote sensing interpretation is verified through manual field review.Comprehensively Considering the topography,meteorology and hydrology,and field verification,8 disaster-causing evaluation factors are selected,and the information coupled MaxEnt model(Ⅳ-MaxEnt)is used to evaluate the susceptibility of landslides in dense vegetation mountainous areas.The evaluation results show that the empirical RMS value of the receiver operating characteristic curve(ROC)of the evaluation model is 0.901,indicating that the accuracy of the model has high accuracy,which is of great engineering significance for the route selection,construction and operation stages of the expressway.
为研究大吨位PC箱梁在整孔预制过程中水化热温度场的分布特征和发展规律,对50 m PC箱梁在浇筑过程中进行了水化热温度场的现场监测和分析.研究结果表明:箱梁在整孔预制过程中水化热温度呈现出"快速升温—高温持续—缓慢降温"的发展过程,各截面温度分布左右对称,最高温出现在S1截面腹板中部的芯部,达到74℃,S1、S2截面的最高温度均超过了 70℃,且高温持续时间较长;各截面温差呈现出"快速增大—缓慢减小"的发展过程,最大温差均出现在腹板—顶板交接处与顶板表面之间,且左右两侧温差分布基本一致,S1、S2截面的最大温差均超过25℃,易造成混凝土的开裂,应在箱梁施工过程中采取相应的控温措施.研究成果可为大吨位PC箱梁的整孔预制提供参考.
The CPC Central Committee has positioned Xiong’an New Area as an “innovative development demonstration area for implementing the new development concept”. The transportation of Xiong’an new area should set a good example and take the lead in the comprehensive, accurate and complete implementation of the new development concept. Transportation bears the functional positioning of “pioneer”, “main skeleton” and “relief carrier” in the planning and construction of Xiong’an new area. Focus on the long-term strategic planning and vivid practice of 15 main directions of transportation development in Xiong’an new area. Systematically deconstruct the experience, measures and schemes of Xiong’an transportation to fully grasp, accurately understand and totally implement the new development concept. It provides an important reference for accelerating the pilot construction of traffic power in Xiong’an new area and building a traffic demonstration benchmark for implementing the new development concept.
Business model innovation faces multiple tests of legitimacy. Most extant research in this area has been conducted from institutional and strategic perspectives while paying insufficient attention to the perspective of evaluators. Based on the institutionalization of China's online car-hailing industry from 2012 to 2018, this paper analyzes the legitimacy judgment of the stakeholders from the perspective of evaluator categorization and explores the legitimation mechanism of business model innovation. It finds that evaluators judge the legitimacy of business models based on category cognition. Therefore, to achieve the bridging, spillover, and accumulation effects of legitimacy, the legitimation strategy of online car-hailing platforms should dynamically adapt to different evaluators, judgment models, and categorization standards. Ultimately, as quantitative changes lead to qualitative changes, the legitimation of innovative business models is achieved in this way. In this process, stakeholders categorize and evaluate online car-hailing based on prototypes and value goals, and establish a two-way interactive mechanism, which is from behavior guided by cognition to cognition given feedback by behavior. This paper combines the legitimacy judgment with category theory to explain how individual cognition drives the emergence of new categories and identifies a series of legitimacy strategies based on categorization, thus providing theoretical support and practical inspiration for exploring the legitimation of business model innovation.
For the bridge tower with large inclination angle, the beam element in Midas finite element software is used to model and analyze the bridge tower structure, and its accuracy is difficult to guarantee. In this paper, taking the construction of a suspension bridge’s inward-inclined tower as the research background, the finite element simulation of the inward-inclined bridge tower is carried out by using the two modeling methods of the beam element and the solid element. The calculation accuracy of the beam element model, the specific position and the jacking force applied by the active transverse brace of the inward-inclined bridge tower are determined, and the field test of the tower bottom stress during the construction process is performed. The results show that: when the inclination angle of the bridge tower is small (5 °), the beam element element is used for modeling and analysis, which has fast calculation speed and high calculation accuracy; When the inclination angle is 15 °, the error of the beam element model exceeds 30%, and it is recommended to use the solid model for calculation; the active cross brace plays a key role in controlling the stress at the bottom of the tower column before the lower cross beam is applied. And after the construction of the cross beam, the active cross brace forms a closed frame structure with the lower tower column, and the subsequent cross brace has little impact on the stress at the bottom of the tower column; Compared with increasing the number of temporary cross braces, increasing the jacking force can improve the stress at the bottom of the tower. And by adjusting the position of the active cross brace and applying the appropriate active jacking force, the stress at the root of the tower column can be greatly improved.
针对共振碎石化后沥青加铺层的反射裂缝防治机理和作为长寿命路面结构的应用问题,使用有限元方法对水泥混凝土路面沥青加铺层和共振碎石化后沥青加铺层的受力特性和疲劳寿命进行了分析,研究了共振碎石化后沥青加铺层在各影响因素下的裂缝尖端应力强度因子和疲劳寿命变化规律.结果表明,共振碎石化技术有效减小了沥青加铺层的层底应力和裂尖应力强度因子,疲劳寿命是水泥混凝土路面直接沥青加铺层的8.75倍,可满足长寿命路面的设计要求.共振碎石化后沥青加铺层的疲劳寿命随面层模量和轴载的增大而递减,随共振结构层模量的增大而先减后增,随面层厚度和车速的增大而递增.
浮式跨海大桥是实现横跨宽广深邃峡湾或海峡的理想结构.回顾了浮式跨海大桥结构的演进和流固耦合作用模拟技术的发展,总结了两种不同的浮式跨海大桥结构数学模型的构建方法(将浮桥视为超大型浮式结构或多浮体系统);给出了浮桥结构的数学模型和数值方法,指出流固耦合作用对结构荷载、结构阻尼等的影响是不可忽略的;总结了求解运动方程的频域方法和时域方法,指出时域方法在解决非线性问题时更具优势;比较了两种常用于浮桥结构中系泊系统的数值模型(准静态模型和动态模型)的优劣.在此基础上,阐明了现有浮桥模拟技术的不足,提出需要为离散型浮筒支承的浮式跨海大桥建立黏性流体、多结构体、阻尼系统和锚泊系统全耦合的数学模型.最后,对浮式跨海大桥流固耦合作用模拟方法进行了展望.
随着大规模公路路网的建成,下一步的发展重点将转向公路基础设施的运营管理.为了充分发挥公路管养过程中数据价值并增强各类数据的可读性,主要围绕公路基础设施数字化管养的目标,结合SpringBoot+VUE轻量级框架以及ECharts前端数据可视化技术研究设计了一种搭建高效、通用性强的公路数字化管养平台快速开发框架,并进行了平台实现和应用.通过对公路管理各阶段数据关系以及管养业务需求进行分析,设计平台总体架构和功能模块,进行平台技术架构选择和平台前后端开发.最后,通过在苏州实地实验对平台进行应用验证.该平台实现了管养数据可视化、整合和挖掘、交互与共享,提高管养业务效率、积累公路数据资产.
以湖北宜巴高速咸池沟大桥下游处渣场中的千枚岩弃渣为研究对象,结合室内大型三轴试验,基于离散元软件PFC 3D,建立了大型三轴剪切试验数值模型,从宏观和细观角度分析了含石量对土石混合体剪切特性的影响以及试样变形破坏的机理.试验结果表明:试样的内摩擦角随含石量的增加而增加,黏聚力则随着含石量的增加呈现出先增加后减小的趋势,在50％含石量处取得最大黏聚力;剪切过程中试样的体应变表现为先剪缩后剪胀,含石量越高,剪胀性越强;从细观尺度上揭示了土石混合体在剪切中变形破坏的机理,初期的剪缩是由于加载板向下移动,试样被压密、高度减小所致,剪切中后期试样中部的颗粒朝向与竖直方向呈约45°的方向向两侧运动,形成两个共轭剪切带,试样在宏观上表现剪胀,随着含石量的增加,试样中部颗粒运动的速度更快,宏观表现出的剪胀性越显著.
超声检测设备的垂直线性或增益线性直接影响缺陷当量尺寸的准确度.针对A型脉冲式超声检测仪器或设备,标准GB/T 27664.1-2011、GB/T 27664.3-2012以及检定规程JJG746-2004中提出了三种垂直或增益线性的测试方法和性能要求,JB/T 9214-2010中也提出了垂直线性测试方法和NB/T 47013.3-2015中提出了相对应的性能要求.作者采用不同标准、规程中提出的四种方法对同一台超声检测设备的垂直或增益线性进行测试,对这四种测试方法和性能要求做出了详细对比.GB/T 27664.1的方法适用于制造或维修后的超声检测仪,其性能要求最严格,验收标准为全屏高度±2％以内;GB/T 27664.3的方法适用于按规定周期在检测现场的超声仪器和探头的组合设备,验收标准为全屏高度±2％～±3％以内;JJG746适用于超声仪的检定校准,验收标准为不大于6％;JB/T 9214的方法适用于按规定周期在检测现场的组合设备,NB/T 47013.3中的验收标准为不大于5％.四种方法的侧重点不同,为不同场合垂直线性或增益线性的测试提供了借鉴.
由于起升高度限位失效引起的起重机械事故较多,为提高起重设备本质安全,降低事故发生率,国家市场监管总局在全国范围内开展了起重机械隐患排查治理工作,要求新出厂的桥门式起重机加装高度限位装置,在用的桥门式起重机逐步加装高度限位装置,对高度限位装置的数量和形式作出了明确的要求,但未明确高度限位装置应达到何种控制要求.通过对一台典型的桥门式起重机的电气原理图的控制电路提出改进措施,以达到提高设备安全性和便于维修的目的.对于电动单梁起重机,根据其不同的使用场所,提出不同的控制要求,便于大量使用的电动单梁起重机通过简单的线路改进提升本质安全,实现快速的整改目的,有助于本次隐患排查治理工作的顺利推进.
焊接是压力管道安装施工的关键步骤,焊缝也是在安装和使用过程中最容易产生缺陷的位置.本文分析了压力管道焊接缺陷的常见类型及其影响,引用机械设计制造工艺相关理论,并结合具体检验案例,指出了城镇燃气压力管道施工单位质量控制方面的关键要点,论证了压力管道安装使用过程中检验检测工作的重要性.
锅炉是能耗大户,特别是近些年来,随着社会经济发展,环境保护力度加强,淘汰了环保不达标的燃煤锅炉,新安装的锅炉以燃天然气居多,但燃气使用成本比以前燃煤高许多,所以为了降低锅炉能耗,节约成本,在锅炉尾部烟道设置烟气热量冷凝回收装置节能冷凝器;但是在实际生产中,节能冷凝器安装使用过程中也产生了新的问题,同时由于节能器不属于锅炉本体的承压部件,容易被忽视,如果操作或者安装不正确,会带来严重的安全隐患,本文是作者结合在工业锅炉检验工作中,对常压节能冷凝器发现的一些问题,以及可能产生的后果进行探讨分析并总结经验.
本文针对压力容器监督检验过程中发现不符合项时,提出运用模糊评价法对发现的不符合项风险等级和整改成本进行评价,评价结果分为高、中、低三个等级,再构建不符合项严重程度等级评估矩阵.将严重程度评估为高等级作为监督检验机构签发《特种设备监督检验意见通知书》的依据,严重程度评估为中、低等级时则由监检员发出《特种设备监督检验联络单》.
针对通用有限元软件应用到产品设计分析中的建模复杂、工作量大、耗时费力的问题,提出利用ANSYS提供的二次开发工具APDL参数化编程语言,面向U型门式起重机整体结构为对象,利用APDL语言建立门式起重机参数化有限元分析模型,通有限元计算结果与理论计算对比验证,跨中最大应力差1.48％,最大变形差1.2％;悬臂最大应力差4.7％,最大变形差6％,表明计算准确可靠,对门式起重机设计提供了具有工程意义的分析手段.
近年很多飞行塔类游乐设施将电梯限速器引入到设备中,作为下行超速的保护装置.而游乐设施使用单位不同于电梯维护保养单位,对限速器日常使用和维护保养不熟悉.本文重点指出游乐设施使用单位对于限速器的维护保养.
PE管道电熔接头相控阵超声检测技术是一项新型、成熟的无损检测技术,NB/T47013.15-2021相控阵超声检测标准与2021年颁布实施,但如何在现场进行电熔接头相控阵检测,标准要求却相对模糊,本文通过对PE管道电熔接头相控阵超声检测设备详细介绍,对该检测技术全过程测试,使该技术能够正确应用于现场检测.
