Abstract:

Line 1 of Hangzhou Metro passes through Qiantang River formation, which contains large amount of methane. Therefore, there is great risk in shield tunneling. The methane is mainly located at the junction between the silty clay and silty sand. Methane releasing trials are made so as to understand the occurrence characteristics of the methane and, in turn, to make preparations to take countermeasures. During the shield tunneling, no methane outburst occurs, which demonstrates that the methane releasing is effective.

Key words: Line 1 of Hangzhou Metro, methane, occurrence, release, blowout