Abstract:

Nowadays, shield tunneling in fractured bed rock zones and uppersoft lowerhard ground is widely discussed. In the paper, two project cases, i.e., Shiziyang tunnel on GuangzhouShenzhenHong Kong highspeed railway and Xiangjiang rivercrossing tunnel on ChangshaZhuzhouXiangtan intercity highspeed railway are studied, with the geological conditions of these two tunnels, problems occurring during tunneling and countermeasures taken analyzed. The adaptability of EPB shield and slurry shield to such unfavorable geological conditions is analyzed, and recommendations are made on the application of dualmode shield and cutting tool replacement under atmospheric conditions. The paper can provide reference for similar project in the future.

Key words: tunnel, fractured zone, uppersoft lowerhard ground, surface subsidence, building subsidence, EPB shield, slurry shield