Abstract:

The author summarizes the types and characteristics of Metro works accidents, introduces the stateofart of shieldbored tunnels both in China and foreign countries, especially the stateofart of shieldbored tunnels in Beijing, analyzes the advantages and disadvantages of tunnels bored by shield machines and discusses the necessity to study on risks in construction of shieldbored tunnels. The author focuses on 11 major risks in construction of shieldbored tunnels, i.e., risks in geology forecasting accuracy, risks in adaptability and reliability of shield machines, risks in shield launching and arriving, risks in instability of working face, risks in tail seal failure, risks in boring in heterogeneous ground, risks in severe ground loss and differential settlement, risks in encountering obstacles, risks in tunnel uplifting, risks in connection tunnel construction and risks in instability of open cut foundations, and provides feasible countermeasures. Besides, he introduces and analyzes the typical accidents occurring during the construction of shieldbored tunnels both in China and foreign countries. This paper can provide reference for the analysis, prediction, prevention and evading of risks in construction of shieldbored tunnels in the future.

Key words: shield bored tunnel, construction, risk, evading, countermeasure, Metro, accident