Risk-based Design Research Of Escape Channels In Shanghai Yangtze River Tunnel

With the social development and industrial progress, more and more highway tunnels are built, and the occurrence probability and impact of tunnel fire have been growing as well. Since tunnel fire is so rampant, the problems concerning with rescue and escape, with the loss of damage, and with the setting laws of escape channels in the tunnel for the sake of escape have been hot issues in underground engineering research. This paper takes Shanghai Yangtze River Tunnel as the background, relies on the National Scientific and Technological Support- Research of Hazard Prevention and Mitigation of Urban Underground Space (2006BAJ27B04), relies on State Hi-tech Research and Development Plan of 863 Program- Research of Long Tunnel Project Risk Assessment and Early Warning Technology (2006AA04Z442), and relies on New Century Excellent Talents Program of Ministry of Education (NCET-04-0368). The basic theory of risk, such as Fuzzy Comprehensive Evaluation and Fault Tree Analysis, as well as FDS (Fire Dynamics Simulator) theory are used to obtain the rational space of escape channels, for example connection tunnels. The conclusions and results of this paper will provide some references to escape-rescue section design of road tunnels. The main contents of this paper are shown as follows.Firstly, four ways of escape methods in tunnel are discussed carefully. They are bottom escape channel, connection tunnel, shaft and service tunnel. Their strong points and shortcomings are analyzed, which eventually indicate their applicable conditions.Secondly, thousands of road tunnels are collected and researched to find out the factors, which may influence the setting of escape channels. Finally forty-five factors are obtained, which reflect both the concern of construction and concern of fire condition in operation period. AHP is used to get the weight of these factors to the setting of escape channels. Fuzzy Comprehensive Evaluation is used to choose the suitable type of escape channels in Shanghai Yangtze River Tunnel.Thirdly, FDS software is used to simulate the fire condition of Shanghai Yangtze River Tunnel, considering different wind velocity values. Three values of temperature, visibility and concentration of carbon monoxide are being compared to get the available safety egress time. At last, the setting space and section of escape channel are provided by making use of the evacuation empirical formula, which assumes that running people may be viewed as a flow.Fourthly, FTA is being used to evaluate the risk points of construction of connection tunnel in Shanghai Yangtze River Tunnel. The most risky events are being obtained as well as the corresponding measures.