Abstract: The construction procedure, construction method and construction technology of “subtunnel into main tunnel” method are presented, with the construction of doublearch mined tunnel constructed by “subtunnel into main tunnel” method of XiliDaxuecheng section on No. 5 line of Shenzhen Metro as an example. The problems occurred during the excavation, such as large ground settlement, much water leakage and bad watersealing effect and the improvement of the lining method, are analyzed. The treatments are proposed according to the experience. The paper can provide reference for similar projects in the future.

Key words: urban Metro, doublearch mined tunnel, “subtunnel into main tunnel&rdquo, method