桥梁桩基施工技术应用研究

文章对桥梁桩基施工技术的应用进行研究,主要介绍桥梁桩基施工的重要性,阐述桥梁桩基施工流程,总结桥梁桩基施工技术优缺点及桥梁桩基施工技术优化策略。希望通过相关研究,为桥梁桩基施工技术的实际应用提供一定的参考。     

桥梁桩基施工常见质量问题及处治措施

文章根据桥梁桩基施工实践,分析了桥梁桩基施工中的常见质量问题,提出了针对性的处治措施,为施工企业的桩基施工工作提供经验借鉴。     

桥梁桩基施工中的常见问题及处理措施探讨

在桥梁工程施工的过程当中,桥梁桩基施工是相对比较重要的一个部位,桥梁桩基能够有效分散桥梁上方所承载的压力,并将其转移到桥梁的地基上,以此减少对桥梁的损害。因桩基的施工质量对桥梁工程的整个施工质量会产生最直接的影响,对桥梁的功能、结构、使用寿命等方面有着积极作用,基于此,我们一定要重视桥梁桩基施工的质量问题。但在实际桥梁桩基施工的过程中,在多种不利因素作用和影响之下,会出现很多问题,进而导致桥梁桩基出现质量问题,受到破坏。本文中,笔者对我国桥梁桩基施工过程中的一些关键技术进行了总结,对施工过程中出现的一些问题进行了研究,并对产生这些问题的主要原因进行了分析,最终根据这些原因提出了一些有效的处理对策,旨在提升桥梁桩基施工的整体质量和水平。     

桥梁桩基施工中存在的质量问题及解决策略

桥梁桩基施工质量的好坏直接决定了整个桥梁的稳定性和使用寿命,因此对桩基的施工质量控制成为重中之重。基于桥梁桩基施工中的重要性进行分析,探讨了桥梁桩基在施工中存在的问题,提出桩基施工质量控制优化及问题处理措施,指出在解决施工中存在的问题时,要根据实际施工现场情况来选取施工工艺和相关技术,对各个环节严格把关,从而提高施工质量。     

喀斯特地区桥梁桩基稳定性评价及施工决策优化设计

由于桥梁桩基工程属于地下隐蔽工程,工程质量除受岩土工程条件、基础与结构设计、桩土相互作用、施工工艺以及专业水平和经验等关联因素影响,另外喀斯特地区的地面塌陷,也会降低桥梁基础的稳定性,对桩基施工质量造成破坏。文章通过研究基于模糊算法的六冬水库大桥桩基施工项目实例,提出喀斯特地区桥梁桩基施工决策方法,构建喀斯特地区桥梁桩基稳定性模糊评价模型,优化了喀斯特地区桥梁桩基设计和施工过程,确保了决策的正确性,在提高桥梁基础稳定性和桩基施工质量方面发挥了积极作用。     

地铁隧道施工对附近桥梁桩基的影响及控制措施研究

地铁隧道施工过程中会对附近的桥梁桩基造成扰动等影响,对桥梁结构的稳定性带来一定冲击。文章介绍了桥梁桩基的作用机理,分析了桥梁桩基各部分载荷受力情况,并对引起桥梁桩基形变的主要因素以及桥梁桩基形变的主要模式进行了研究,提出了控制桥梁桩基形变的具体措施。     

山区斜坡桥梁桩基施工策略研究

文章对山区斜坡桥梁桩基的载荷原理进行了分析,并结合桩基附近地质的弱化特点,提出了山区斜坡桥梁桩基施工稳定性控制模型,通过特定试验结果对比、分析和验证了该模型的正确性与可行性。同时,对桩体的弹性阈量以及嵌固深度等进行了细致的讨论,研究其对山区斜坡桥梁桩基施工过程中的稳定性的影响,研究表明,桩基深度以及弹性阈量对山区斜坡桥梁桩基在施工过程中的稳定性均有较大影响。     

某大桥裸露斜坡岩层桩基施工

某桥梁部份桩基位于直接裸露的岩面上,且岩层的倾斜面度达到20度左右,本桩基的施工,为其它相似类型桥梁的桩基施工提供了参考和借鉴。     

公路桥梁桩基施工质量影响因素分析

为提高公路桥梁桩基施工质量,分析公路桥梁桩基施工的影响因素,阐述常见的质量问题,提出对应的解决策略,得出桥梁桩基施工质量控制方法。     

岩溶强发育区桩基施工技术研究

针对柴河特大桥岩溶强发育区桩基施工特点,以12#主墩桥梁桩基施工为例,对岩溶强发育区桩基施工方法及特点进行阐述,重点对地质核查、施工准备、外钢护筒设置和冲击钻孔施工等流程进行系统说明。研究成果为岩溶地区桥梁桩基施工提供了参考。     

管道风险分析指数评分法中分值调整初探

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。     

A new approach for modeling of Fundamental Diagrams

According to the intra-vehicle interaction, a traffic flow can generally be divided into three homogeneous states (1) that of free driving, (2) that of bunched driving, and (3) that of standing. The parameter describing the state of free driving is the desired speed, for the state of bunching it is the intra-vehicle gaps (time headway) within the convoy and the mean speed of the convoy, and for the state of standing it is the maximum jam density. These are the most essential parameters which do not depend on the actual traffic situation.This paper introduces a new model which considers the Fundamental Diagram (equilibrium speed–flow–density relationship) as a function of the homogeneous states. All traffic situations in reality can be considered as combinations of the homogeneous states and therefore can be described by the essential parameters mentioned above. The non-congested (fluid) traffic is a combination (superposition) of the states of free driving and bunched driving, the congested (jam, stop, and go) traffic is a combination of the states of bunched driving (go) and standing (stop). The contribution of the traffic states within the differently congested traffic situations can then be easily obtained from the queuing and probability theory. As a result, Fundamental Diagram in all equilibrium traffic situations is derived as simple functions of the essential parameters.According to the new model the capacity of freeways and rural highways can be determined by measuring the essential parameters. This is much easier than measuring the capacity directly.Furthermore, the probabilities of the various traffic states can be obtained from the new model. This leads to new possibilities in real-time controlling and telematics.The new model is verified by comprehensive measurements carried out on freeways and rural highways in Germany.     

输油站场清管系统应力分析

清管是输油管道重要的常规作业之一,是保证管线长期按照设计输量运行的重要保障。目前,对输油站场的清管系统在运行工况下的应力分析较少,特别是没有考虑由于清管器本身对管道所造成的冲击对管道应力分布的影响,所以有必要对输油站场清管工况下的管道进行应力分析。文中采用CAESAR Ⅱ软件对某输油站清管工况下管道系统进行应力分析,建立了清管器受力模型,通过编制VB程序计算了清管器的冲击产生的集中应力大小,并以假设清管器产生的冲击力最大的情况下得出整个管道的一、二次应力分布,找出了一、二次应力分布的关键点,并进行了校核,满足管道的强度要求,所用方法有利于更好地保证清管作业安全。     

Competition policy and the liberalisation of European aviation

The European aviation industry is undergoing a process of liberalisation. One of the important lessons of American deregulation was that the industry is not perfectly contestable. One implication of this is that actual competition on a route is important in order to be able to secure the benefits of deregulation or liberalisation. Another is that effective competition policy is important in order to prevent anti-competitive mergers or predatory behaviour. This paper reviews the merger investigations in European aviation which have accompanied the search by carriers to secure the benefits of market power, and considers the extent of route competition within the European Community and its relationship to the different route licensing policies of different national governments. The paper considers the extent of present competition on the busiest routes, and stresses the importance of cabotage rights in opening up the European market to effective competition.     

The quality of survey data: Telephone versus face-to-face interviews

Those designing surveys and producing data have always been concerned about its quality. The increasing stringency of the financial constraints which affect public authorities and the increased scope of involvement in the regulation of urban travel has led us to pay even greater attention to the quality of data. This issue is frequently covered in the literature on survey methods. However, comparisons between different survey methods are more rarely conducted. The decision to conduct such an analysis is partly the result of the development of telephone use to the detriment of other survey modes in many countries and also the development of Computer-Aided Telephone Interviewing (CATI) which facilitates the running and monitoring of the survey.This paper examines several aspects of this question in order to compare the performance of telephone and face-to-face interviews. The first aspect is the representativeness of the sample, and therefore relates mainly to the issue of nonresponses and the choice of a sample base. The second concerns the accuracy of the information and involves the choice of a survey area and the recording of all trips, including short-distance travel. Finally, the quality of data is obviously determined by the quality of the responses given by those interviewed.The answers we give frequently depend on the objective of the surveys, which leads us to put forward a table which summarizes the performance of telephone and face-to-face interviews on the basis of the main objective of the survey. Broadly, the telephone seems to be the favoured tool for surveys in the area of transport planning and surveys which aim to provide data for forecasting models, mostly on the grounds of cost. However, face-to-face techniques are often preferred for surveys which aim to discover and analyze the factors which explain individual travel behaviour.     

Development and evaluation of a knowledge-based system for traffic congestion management and control

This paper describes a real-time knowledge-based system (KBS) for decision support to Traffic Operation Center personnel in the selection of integrated traffic control plans after the occurrence of non-recurring congestion, on freeway and arterial networks. The uniqueness of the system, called TCM, lies in its ability to cooperate with the operator, by handling different sources of input data and inferred knowledge, and providing an explanation of its reasoning process. A data fusion algorithm for the analysis of congestion allows to represent and interpret different types of data, with various levels of reliability and uncertainty, to provide a clear assessment of traffic conditions. An efficient algorithm for the selection of control plans determines alternative traffic control responses. These are proposed to an operator, along with an explanation of the reasoning process that led to their development and an estimation of their expected effect on traffic. The validation of the system, which is one of only few examples of validation of a KBS in transportation, demonstrates the validity of the approach. The evaluation results, in a simulated environment demonstrate the ability of TCM to reduce congestion, through the formulation of traffic diversion and control schemes.     

Effects of built environment on walking at the neighbourhood scale. A new role for street networks by modelling their configurational accessibility?

The hypothesis of this paper is that some features of the built environment, particularly those concerned with the accessibility of the street network, could be associated with the proportion of pedestrians on all trips (modal split) found in different parts of a city. Quantitative analysis (bi-variate correlation and a multiple regression model) was used to establish the association between variables. The study area covered a substantial part of the metropolitan area in Madrid, Spain. Results showed a consistent influence of five particular indexes in the multi-variate model. Not surprisingly for this kind of research, four of them described density and mix of land uses. But perhaps more interestingly, the first one was a measure of the accessibility of the public space network, a less prominent variable in literature to date. This variable is called herein configurational accessibility, calculated using Space Syntax, an urban morphology theory. The relevance of configurational accessibility is probably related to its surprising ability to synthesize global and perceived properties of street networks at the same time. The findings introduce the idea that the configuration of the urban grid can influence the proportion of pedestrians (as a part of total trips in any transport mode) who choose to walk on single-journey trips. The discussion links with the current debate about walkability indexes and the need of empirical support for the chosen variables and also with transport planning. Because the relevance of the street network’s role is not so easy to grasp, inputs from configurational theory and the pedestrian potential underlying this fact are also discussed at the end of the paper.     

Financing urban rail projects: The case of Los Angeles

This paper describes the potential use of the financing strategy of value capture or benefit assessment for an urban mass transportation project. The paper describes the legal background to the use of benefit assessment, and the process of implementation for the first construction phase of the Los Angeles Metro Rail project. The process of developing the benefit assessment structure was a consultative one, utilizing technical inputs from a team of specialist consultants, a task force consisting of major developers and property owners in the affected area, and politicians representing many of the interests in the region. The initial benefit assessment districts were set up to raise $130 million of the cost of the first 4.4 miles of the rail project, and are based on the benefits accruing to certain categories of property in the vicinity of stations. The assessment would be collected for about 18 years and bonding would be used to provide the capital at the time of construction.The paper describes the procedure for setting boundaries, the structuring of the assessment rates, the definition of benefiting properties, and the uses and tenure of the assessment. In almost all cases, the theory of value capture indicated a different result than was achieved from a consensus of the task force, and the nature of these differences is explored in the paper. The establishment of the benefit assessment districts withstood early court challenges, but has subsequently been appealed and was overturned on appeal. Action is pending with the Supreme Court currently, and efforts are also underway to pass new legislation to deal with some of the issues raised in the court proceedings.