Abstract:

Jiefangdalu station is an interchange station between Line 1 and Line 2 of Changchun Metro. The station is constructed by topdown construction method under the protection of castinsitu arch. The excavation sequence of the pilot tunnels is optimized so as to shorten the construction period and facilitate the construction organization. The ground surface settlement data of the station is analyzed and the pattern of the ground surface settlement of stations in Northeast China constructed by topdown construction method under the protection of castinsitu arch is obtained. The causes for the ground surface settlement are analyzed in terms of ground conditions, construction techniques and construction process. Countermeasures, including grouting reinforcement, proper pilot tunnel construction sequence and proper support dismantling, are proposed so as to control the ground surface settlement.

Key words: Metro station, topdown construction method under protection of castinsitu arch, ground surface settlement