Abstract Because of the complexity and uncertainty of geological conditions, risk assessments for the construction safety of underwater shield tunnels have become an important research topic in underground engineering. Based on the Nanjing Weisan Road river-crossing tunnel construction, this paper analyzes the identification of construction risk factors and evaluation of construction risks in the shield-driven section and formulates control measures for the various risk factors. The analysis results show that hyperbaric intervention in the shield chamber is the primary goal of risk control for such shield tunnels as the Nanjing Weisan Road river-crossing tunnel, which passes through mixed ground with high water pressure and permeability for long distances. Risk may be reduced by reducing the changing times of cutters, setting a reasonable face support pressure and ensuring the formation of a stable filter cake on the working face. Risk during the process of shield tunnelling is mainly controlled by the detection of shield tunnelling parameters and cause analysis of parameter anomalies while the shield machine is shut down; complete risk control measures, such as a risk emergency plan and emergency supplies, are also important measures for reducing risks.
Abstract：
Because of the complexity and uncertainty of geological conditions, risk assessments for the construction safety of underwater shield tunnels have become an important research topic in underground engineering. Based on the Nanjing Weisan Road river-crossing tunnel construction, this paper analyzes the identification of construction risk factors and evaluation of construction risks in the shield-driven section and formulates control measures for the various risk factors. The analysis results show that hyperbaric intervention in the shield chamber is the primary goal of risk control for such shield tunnels as the Nanjing Weisan Road river-crossing tunnel, which passes through mixed ground with high water pressure and permeability for long distances. Risk may be reduced by reducing the changing times of cutters, setting a reasonable face support pressure and ensuring the formation of a stable filter cake on the working face. Risk during the process of shield tunnelling is mainly controlled by the detection of shield tunnelling parameters and cause analysis of parameter anomalies while the shield machine is shut down; complete risk control measures, such as a risk emergency plan and emergency supplies, are also important measures for reducing risks.
.Construction Risk Assessment for the Shield-Driven Section of the Nanjing Weisan Road River-Crossing Project[J] MODERN TUNNELLING TECHNOLOGY, 2015,V52(4): 49-54
2015, Vol. 52 