Abstract:

 Taking a project in Shanghai as example, this paper briefly introduces the parameters and methods of horizontal freezing technology at the shield machine launching shaft and some special notice items in construction. The process flowchart of EPB shield boring in horizontal freezing soil and the methods and special measures to prevent freezing of cutter head and water and sand gushing at the portal are presented in detail. The influence degree of frostheave and thawingsubsidence is analyzed on basis of the monitoring data. Measures such as special segments, embedded injection pipes in station structure and tracing grouting are taken to avoid the influence of frostheave and thawingsubsidence on the environment. Thus the safety of shield machine launching and ground surface environment is ensured.