Abstract:

The cost and risk increase with shield diameter increase. Based on Shiziyang Tunnel on FoshanDongguan Intercity Railway, the risks existed in equipment type selection, longdistance deadend tunneling, uppersoft lowerhard strata and fault and fracture zone during largediameter slurry shield boring in complex strata with high water pressure and strong permeability are analyzed. The equipment adaptability is improved from the selection of atmospheric pressure cutterhead and slurry circulation system; the excavation parameter control method for excavation management and slurry management is determined; and construction countermeasures for uppersoft lowerhard strata and fault fracture zones are proposed to avoid significant geological risks and ensure construction safety of underwater largediameter shield.

Key words: largediameter slurry shield, construction risk, control countermeasure, equipment type selection, tunneling parameter, uppersoft lowerhard strata, fault fracture zone