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1、地铁项目的数据通信系统总体设计，研发，测试，实施DCS、SDH、无线通信、地铁无线覆盖、铁路通信信号应用化开发Wireless networking in tunnelling projectsTunnelling and Underground Space Technology隧道和地下工程空间科技学学报Emerging collaborative technologies and working methods often require tremendous engineering and organisational efforts for successful implementat
2、ion of information and communication technologies (ICTs). According to a research conducted in Turkish construction industry, most of the problems that occur during the construction phase are due to lack of co-operation and communication between designers and contractors and lack of prompt expert de
3、cisions during on-site engineering. Similar to any major construction project, tunnelling projects success is highly dependent on collaborative team work where communication and information exchange take place between project members. Distributed collaborative teamwork, as the case in most of the la
4、rge scale construction projects as well as tunnelling projects, empowered by state of the art information and communication technology, promises more efficient work processes, reduced travelling needs, and increased opportunities for project communication. Following the fast development of mobile co
5、mputing in recent years, many sectors have adopted mobile devices and wireless technologies enabling real-time information transfer thereby improving business processes. For some years, the feasibility of implementing wireless solutions to construction sites has been researched. Potentially, mobile
6、and wireless technologies enable construction staff to be more flexible in terms of location and time. For better use of mobile collaboration in construction projects, mobile technologies and construction sector have to be examined in some detail to implant the most suitable technology for real-time
7、 information access and improved collaboration of distributed teams in construction. However, case studies in construction are very limited in number and scope. This paper discusses and proposes an implementation scenario of wireless networking in Marmaray; a multi-site tunnelling project in Istanbu
8、l. Benefits, possible problems and cost assessments are discussed.Article Outline1. Introduction2. Tunnelling projects and the relevance of efficient communication3. Wireless local area networks (WLANs) 3.1. WLAN design3.2. WLAN security4. Implementation Scenario Marmaray project 4.1. Project detail
9、s . Immersed tunnel under Bosphorus. Underground tunnels. Stations4.2. Proposed mobile collaboration in marmaray project & WLAN design . Mobile collaboration .1. Advantages of using wireless communication and mobile collaboration.2. Execution of the works. Wireless local area network design and calc
10、ulation of overall system cost .1. High gain directional antenna (ANT24-1801).2. Wireless access point (DWL-2700 AP).3. Estimated overall system cost for Marmaray project5. Conclusion6. Further researchMonitoring of rail corrugation growth due to irregular wear on a railway metro curveWearShort-pitc
11、h rail corrugation developing on the low rail in sharp curves is a problem experienced by many railway networks worldwide. Because of the large existence of small radius curves, metro lines are particularly affected. This case study is performed as part of a project which aims at developing a numeri
12、cal tool for prediction of rail corrugation growth on curves. The development of corrugation on a 120m radius curve of the Stockholm metro has been monitored by repeated measurements of rail roughness and train pass-by noise. Within a grinding interval of 1 year, severe short-pitch corrugation was b
13、uild up with maximum peak-to-peak magnitudes of about 0.15mm. Spectral analysis of measurement data shows large roughness magnitudes in the wavelength interval 414cm, with peaks at approximately 5cm and 8cm. The corrugation pattern has a pure longitudinal direction (with corrugation ridges transvers
14、e to the track direction) and an irregularly varying magnitude along the 100m long measured track section. The roughness growth rate increased with time until 300 days after rail grinding, thereafter only moderate additional roughness growth was observed. Because of moderate train speeds of about 30
15、km/h, the rolling noise caused by the corrugation has a low-frequency content (200Hz). A 10.1dB unit increase (139300 days after grinding) in roughness level in the wavelength interval 414cm was found to correspond to an increase in rolling noise level in the frequency interval 60200Hz of 4.9dB. In
16、dry weather conditions, discomfort related to pass-by noise is rather linked to the occurrence of wheel squealing than to rolling noise.Article Outline1. Introduction2. Test site 2.1. Traffic conditions and properties of the traintrack system2.2. Measurement setup3. Measurement equipment4. Results 4.1. Gradual development of corrugation4.2. Corrugation characteristics4.3. Train pass
