Risk Management For Beijing Subway Tunnel Construction Using The New Austrian Tunneling Method: A Case Study

According to Beijing Subway's extensive expansion plan, the total length of subway lines will reach 1,050 km by 2020, in comparison with 638 km by the end of 2018. The new Austrian tunneling method (NATM) is widely adopted in Beijing subway construction. This paper proposes a fuzzy analytic network process to evaluate the risk for Beijing subway tunnel construction using NATM. Firstly, the risk breakdown structure (RBS)-work breakdown structure (WBS) was introduced for risk identification and 5 major risk factors of the construction projects were identified. Then the model is refined by two-round of Delphi survey and 16 sub-factors are selected. Secondly, the fuzzy analytic network process (FANP) was used to structure the FANP model hierarchically and the weights of the factors and sub-factors of the FANP were calculated. Finally, the refined model is applied to Beijing Subway Line 6 project and a series of risk control measures were taken. The risk control system was shown to be effective and ensure the success of tunnel excavation. This model is believed to serve as a valuable reference for future subway construction in Beijing using NATM in congested urban area.