Abstract:

The shieldbored running tunnel from Panda Avenue Station to Zoo Station of No. 5 bid section of Phase I project of Line 3 of Chengdu Metro crosses underneath Chuanshan interchange. The mentioned running tunnel is located in mudstone and clay ground, and the interchange above the running tunnel has strict requirement on the ground settlement. The following countermeasures are taken: 1) Special chemical ground conditioning agents are used to control the boring parameters; 2) For sections with high settlement control requirement, prereinforcement from the ground surface is executed before shield passes and reinforcement from inside the tunnel is executed after the shield passes. The construction practice shows that the countermeasures taken can bring the ground surface settlement under effective control and can ensure the safety of the tunneling and the normal operation of the interchange. The paper can provide reference for similar projects in the future. 

Key words: Chengdu Metro, shieldbored tunnel, Chuanshan interchange, reinforcement, monitoring