Abstract:

The water inrush and mud gushing induced large ground surface settlement and segment deformation would occur during earth pressure balance (EPB) shield tunneling in sandy stratum with high water pressure. A refined numerical model for EPB shield tunneling in Xiaodongmen StationWuchang Railway Station section on Wuhan Metro Line No. 7, considering fluidsolid coupling of water and soil, is established so as to study the influences of water inrush at shield tunneling face on ground surface settlement and internal stresses of segment and anchor bolt. The study results show that: 1) The water inrush volume at tunneling face and ground surface settlement show linear relationship; and that and internal stress of segment anchor bolt show nonlinear relationship. 2) Large water inrush volume would lead to squeezing deformation of tunnel crown top, and would further induce damage of segment and yielding of anchor bolt. As a result, attentions should be paid on reducing water inrush volume.

Key words: shield tunnel, earth pressure balance (EPB) shield, fluidsolid coupling, numerical simulation, mud gushing and water inrush at tunneling face, ground surface settlement, internal stress of segment, internal stress of anchor bolt