公路桥梁沉降段的路基设施建设探讨

在进行公路桥梁项目施工建设过程中,沉降段路基的处理是需要重点关注的一环。相较传统施工方式来说,沉降段路基施工要求较高,这是因为施工环境已经产生了变化,要保证选择的路基设施科学合理、符合实际施工情况,方可充分保证公路桥梁项目的整体质量。所以,应该根据施工条件,合理建设路基设施,让沉降段整体质量有效提高,为人们的安全出行提供保障。本文以此展开分析论述,探究了沉降段路基设施建设要点,以期能为同类型工程项目提供有效参考。

高速公路路基排水设施的病害及其治理措施研究

简述高速公路路基排水设施的使用要求,阐述了冲淤破坏、沟渠损坏、进出水口堵塞、超高渐变段积水和路基病害等方面的路基排水设施常见病害。结合实际制定病害处理方案,采用新型施工技术优化排水设施,通过路基边坡加固治理和做好排水设施的养护管理等措施,为治理高速公路路基排水设施的病害提供了有益的参考。

高速公路路基排水设施病害类型及处治技术研究

结合实际工程,详细介绍了高速公路边沟、排水沟、截水沟、急流槽、桥涵以及中央分隔带等部位常见的路基排水设施的病害类型,重点对路基排水设施病害处治措施进行研究。

浅谈公路路基排水施工技术

路基的病害有多种,形成病害的因素也很多,但水的作用是主要因素之一,路基的强度与稳定性同水的关系十分密切。路基范围内排水处理的好坏对路基的整体稳定和防止路基病害具有很大影响,因此路基施工中,必须十分重视排水工程。本文主要从路基排水的目的和任务、路基排水设施和施工方面做了简要的论述。

高速公路路基防护、排水工程施工管理要点

基于目前公路桥梁施工建设质量受水文地质环境的影响,文章以实际工程项目为例,分析了项目施工管理的特点,并提出了优化施工管理的措施方法,其目的是为相关建设者提供一些理论依据。

A Smooth Expansion Model for PKI

The expansibility of PKI is expected to have the features that when the amount of user exceeds the system capacity, the users’ requirement can still be met by simply expanding the number of PKI entities and management levels, and this expansion should be achieved smoothly from the original system. The upward, downward, and horizontal expansions of PKI are discussed in this paper. A path discovery method is suggested to reduce the effect of PKI expansion to the end entities, so as to enhance the availbility of PKI services.

Spatial spillover effects of transport infrastructure on regional economic growth

Spatial spillover effects,either positive or negative,of transport infrastructure,highways/expressways,etc.,on regional economic growth are proposed.Using the panel data for 11 cities of Zhejiang province from 1994 to 2003,a spatial production function is applied to examine the spatial spillovers which can be generated as a positive output spillover from the transport infrastructure between neighboring cities.Some spatial weighted matrices are adopted to define different neighboring cities to measure how easily factors or economic activities can migrate between regions.The estimation results show that the output elasticity of the highway infrastructure in 11 cities are all insignificant at a 5% significance level;hence,highway infrastructure in a region cannot explain the same region's economic growth.On the other hand,the highway infrastructure of other contiguous regions has positive spillover effects on a same region's economic growth.

Infrastructure-based localisation of automated coal mining equipment

A novel radar-based system for longwall coal mine machine localisation is described. The system, based on a radar-ranging sensor and designed to localise mining equipment with respect to the mine tunnel gate road infrastructure, is developed and trialled in an underground coal mine. The challenges of reliable sensing in the mine environment are considered, and the use of a radar sensor for localisation is justified. The difficulties of achieving reliable positioning using only the radar sensor are examined. Several probabilistic data processing techniques are explored in order to estimate two key localisation parameters from a single radar signal, namely along-track position and across-track position, with respect to the gate road structures. For the case of across-track position, a conventional Kalman filter approach is sufficient to achieve a reliable estimate. However for along-track position estimation, specific infrastructure elements on the gate road rib-wall must be identified by a tracking algorithm. Due to complexities associated with this data processing problem, a novel visual analytics approach was explored in a 3D interactive display to facilitate identification of significant features for use in a classifier algorithm. Based on the classifier output, identified elements are used as location waypoints to provide a robust and accurate mining equipment localisation estimate.

Health Impact Assessment of Air Pollution in Some Regions in Albania

Air is the ocean we breathe. Air supplies us with oxygen which is essential for our bodies to live. 99.9% air is nitrogen, oxygen, water vapor and inert gases. Human activities can release substances into the air, some of which can cause problems for humans, plants and animals. There are several main types of pollution and well-known effects of pollution which are commonly discussed. These include smog, acid rain, the greenhouse effect, and ＂holes＂ in the ozone layer. Each of these problems has serious implications for our health and well-being as well as for the whole environment. The age and health condition are more important also at the response opposite the pollution of air. During the last decade in our country such as result of freely population movement, development and growth of their industrial activities, growth of vehicle number, collapse of roadway infrastructure etc., an increase of air quality pollution is evident. In this study, we exhibited the causers, such as increasing of number of the old cars, which is an important factor of the air pollution and, at the same time, we exhibited the pollution indicators of the air quality, such as PM I 0, total dust, dust levels outdoors and indoors, which are in the high levels. These factors indicated on human health. We have observed the health indicators, especially lung diseases such as bronchial asthma with higher percentage, chronic bronchitis and lung cancer. There was consistency in the finding that relates the acute increases in urban air pollution and the short-term health effects or patients suffering from chronic obstructive pulmonary diseases.

Formation of Los Angeles's low density and high car dependence

As a typical car-dependent city, Los Angeles （LA） is extensively used as an example in research to illustrate car influences on city form. Focusing on the features of LA＇s geologic conditions and civil circumstances, we argued that the relationship between LA＇s low-density pattern and car dependence is more involved than previously deemed simple causality. The low density should be primarily credited to the spacious requirement of the mining industry, frequent earthquakes and multiethnic population of the city. Off reserves in LA fueled its economic boom and fast urbanization that coincided with the start of mass production of cheap cars, and cars became medium-priced consumables for average families. Politicians preference for short constrnction-period projects enabled fast establishment of LA＇s highway infrastructure. The popularity of car use in return faciliatated further development of the low-density pattern of the city. The low-density urban form and car dependence created environmental and social problems for LA. Looking at P. R. China＇s motorization and urban development, we found that the trajectory of Beijing＇s motorization between 197g and 2003 coincides with that of the U.S. in the 1910s and 1920s. Lessons from LA＇s urban and transportation development should be suggestive to China＇s urban and transportation planning.

Traffic Calming in Quebec： Speed Humps and Speed Cushions

Speed management is an essential tool in ensuring the improved safety of users of urban roads, particularly vulnerable users. It relies on several measures： awareness campaigns, speed control, as well as the development and operation of the road infrastructure. Municipalities in Quebec are increasingly resorting to the development of traffic calming measures, and are facing numerous questions concerning their installation and their effectiveness. To respond to this need, the ministere des Transports du Quebec （Quebec Department of Transport） has begun publishing a series of fact sheets on a variety of traffic calming measures, including speed humps and speed cushions, raised crosswalks and intersections, neckdowns, centre islands and chicanes. A general fact sheet introduces all of the measures and notably outlines the procedure for pre-implementation analysis. Each fact sheet dedicated to an individual measure outlines the implementation context, advantages and disadvantages, geometric characteristics, effectiveness at reducing speed, and maintenance requirements, including winter maintenance. Two fact sheets are already published： the general fact sheet and the fact sheet on speed humps and speed cushions. The fact sheets as well as examples of measures implemented in municipalities are available on the minist6re＇s web site under Partenaires-Municipalites-Securite routiere.

Railway Accident Prevention and Infrastructure Protection

Railway accident prevention and protection are a key part of a wider picture of transport safety. The rail sector thus needs to improve its knowledge of trespassing and suicide, including at level crossing, in order to work out suitable responses by analyzing measures already taken in various countries, Governments, the rail industry and road organizations have been implementing a variety of countermeasures for many years to improve railway safety. These actions are substantial and have resulted in a continuing decrease in the number and the severity of accidents. This paper presents existing suitable techniques that are used in the preventative measures targeted to reduce railway suicides, trespassing and level crossing user accidents. It describes them in terms of their capability to effectively reduce accidents, their cost-effectiveness and their integration within the railway transport system as a whole.

Scalable and Identifier/Locator-Splitting Routing Protocol for Mobile Ad Hoc Networks

In the traditional Intemet Protocol （IP） architecture, there is an overload of IP sermntic problems. Existing solutions focused mainly on the infrastructure for the fixed network, and there is a lack of support for Mobile Ad Hoc Networks （MANETs）. To improve scalability, a routing protocol for MANETs is presented based on a locator named Tree-structure Locator Distance Vector （TLDV）. The hard core of this routing method is the identifier/locator split by the Distributed Hash Table （DHT） method, which provides a scalable routing service. The node locator indicates its relative location in the network and should be updated whenever topology changes, kocator space ks organized as a tree-structure, and the basic routing operation of the TLDV protocol is presented. TLDV protocol is compared to some classical routing protocols for MANETs on the NS2 platform Results show that TLDV has better scalability. Key words：

Spatiotemporal Patterns of Road Network and Road Development Pri-ority in Three Parallel Rivers Region in Yunnan,China:An Evaluation Based on Modified Kernel Distance Estimate

Road network is a critical component of public infrastructure,and the supporting system of social and economic development.Based on a modified kernel density estimate(KDE)algorithm,this study evaluated the road service capacity provided by a road network composed of multi-level roads(i.e.national,provincial,county and rural roads),by taking account of the differences of effect extent and intensity for roads of different levels.Summarized at town scale,the population burden and the annual rural economic income of unit road service capacity were used as the surrogates of social and economic demands for road service.This method was applied to the road network of the Three Parallel River Region,the northwestern Yunnan Province,China to evaluate the development of road network in this region.In results,the total road length of this region in 2005 was 3.70×104km,and the length ratio between national,provincial,county and rural roads was 1∶2∶8∶47.From 1989 to 2005,the regional road service capacity increased by 13.1%,of which the contributions from the national,provincial,county and rural roads were 11.1%,19.4%,22.6%,and 67.8%,respectively,revealing the effect of′All Village Accessible′policy of road development in the mountainous regions in the last decade.The spatial patterns of population burden and economic requirement of unit road service suggested that the areas farther away from the national and provincial roads have higher road development priority(RDP).Based on the modified KDE model and the framework of RDP evaluation,this study provided a useful approach for developing an optimal plan of road development at regional scale.

Engineering Geological Assessment for Route Selection of Railway Line in Geologically Active Area:A Case Study in China

The Cheng-Lan railway links Chengdu, a central city in Southwestern China, and Lanzhou, a central city in Northwestern China. The railway passes through the Longmenshan fault zone (Wenchuan earthquake happened there on May 12, 2008), Minjiang fault zone, and Dongkunlun fault zone, which are all active. It runs over the Yangtze River and the Yellow River, and crosses high mountains and deep valleys. There exists, along the railway's alignment, different kinds of strata of hard granite and soft, weak metamorphic rocks such as carbonaceous slate, schist, and phyllite. It is, therefore, a key issue for such an infrastructure construction to assess the engineering geological conditions and risks, so as to mitigate or avoid possible georisks and to offer optional designs. Geological survey and georisk assessment along the railway corridor are carried out. Special attention is given to active faults, earthquakes and seismic zones. Based on these, discussions about geological aspects for route selection of the railway are conducted and countermeasures for georisk control are proposed accordingly. Main conclusions are achieved as follows: (1) Geohazards such as landslides, rockfalls and debries flows dominate both the route selection of the railway and the engineering structures (e.g., tunnels or bridges) adopted; (2) Tunnel has been proved to be an excellent structure for linear engineering in geologically active area; and (3) In the case where avoiding is impractical, necessary protection measures should be taken to engineering slopes in high earthquake intensity areas, especially the area with earthquake of Ms. 8 or greater.

Advanced Methods of Evaluating Benefits from Improved Flood Immunity in Queensland

The regular occurrence and the high costs of flooding to both road agencies and communities is a strong impetus to investigate the methodologies applied to evaluating flood immunity road projects. Very little literature exists on methods of evaluating the benefits of improving flood immunity through better road infrastructure. This paper attempts to address some of the numerous issues hindering the accurate evaluation of flood immunity road projects. The methodologies presented in this paper are designed to evaluate benefits that are not normally included or not fully considered in evaluations; such benefits include reduced flood related road accidents, costs of not travelling during the closure period and additional costs from unanticipated flood events. A key focus of the paper is the consideration of the evaluation of improved flood immunity from a network perspective rather than the typical approach of evaluating flood immunity projects in isolation to each other. The application of the proposed methodologies is demonstrated with a hypothetical example of a typical rural network subjected to regular flooding. The results of the analysis, conducted using the proposed methodologies, reveals that the currently applied methodologies account for less than half the likely value of benefits of a package of projects that will prevent the complete isolation of communities during serious flood events.

Comparison of Crack Width and Space between SCC and Conventional Concrete Beams

Concrete is a material which is in wide use in engineering especially in construction engineering and road infrastructure facilities. Development trends for high rise constructions, modern skyscrapers indicate that building such constructions with normal concretes and low consistency is impossible, therefore there is a need for concrete with high processes because of great amount of reinforcement in cross-section of concrete elements. Solution for such construction is self-compacting concrete because of its ability to fill good formworks without compaction and vibration. Considering this fact, researches for cracks, mechanical characteristics of concrete and deformations have been conducted worldwide. In this paper, we conducted an experimental research to determine the cracks on beams of self-compacting concrete and compared it with conventional concrete. The experimentally-obtained results will be presented for both types of concrete for： module of elasticity, compression strength, crack with and cracks spacing for duration failure testing time t = 400 days.

Influence and Control Strategy for Local Settlement for High-Speed Railway Infrastructure

This paper discusses the main impact factors of the local settlement and differential settlement of high- speed railway lines. The analysis results show that groundwater exploitation is the direct cause of differ- ential settlement. Based on the study of ballastless track additional load and of vehicle, track, and bridge dynamic responses under different differential settlements, a control standard of differential settlement during operation is proposed preliminarily.

Aspects of Railway Capacity and Occupation Time Estimation

The priority of the EU transport policy in railway sector is to open up the railway market. The objective is to provide railway undertakings with access to the railway network on equal terms. The main problem is determining the infrastructure capacity. A variety of methodologies are used across Europe for the capacity estimation of railway infrastructure. This diversity has forced railway infrastructure managers to seek a new, common methodology. The UIC methodology is an easy way to calculate the capacity consumption. However, there the possibility to expound this methodology in different ways, which can result in different capacity consumptions. There isan advantage to improve this methodology and to set a clear and unified method of occupation time estimation. The fundamental improvement to UIC methodology is the definition of the occupation time by the trains. This paper gives a description of Slovak and UIC methodologies as a basis for a newly developed approach. The new way of estimation of the capacity consumption （occupation time） is based on a graphic approach. The new methodology concerns the estimation of the infrastructure occupation time and is a conceptual framework developed by the authors for an easier evaluation of occupation time in train traffic diagrams. The new methodology makes the UIC methodology more usable and enables more exact results to be obtained from infrastructure capacity examination.

The Impact of the Maputo Development Corridor on Wealth Creation within the Region It Serves

The Maputo Development Corridor along the N4 toll road between the north-eastern provinces of South Africa and Maputo （the capital and main port of Mozambique） was initiated in 1996. A Development Corridor can be seen as a concept to elevate an area to a certain level of development. One of the objectives of this project was investment in transport infrastructure in order to create an enabling environment for economic growth and development. The project is also in line with the 1995 Spatial Development Initiatives of the South African Government that attempt to improve investment in those areas were the greatest potential for growth exists. This paper addresses economic wealth creation within the broader region that the N4 toll road and the corridor currently serve. The research revealed that the areas closer to the N4 corridor had higher growth in terms of economic output as measured by Gross Valued Added than those further removed. There were a stronger correlation between growth in employment and proximity to the road corridor for the manufacturing, construction, trade and transport sectors. Analysis done also shows that income per capita has grown at a faster rate in areas closer to the corridor that areas further removed.