During the construction of shie ld tunnels，support pressure is usually applied at the work face to prevent u3Do~RyL[
excessive tunneling—induced soil movement or collapse．However，the selection and control of appropriate support PV,"-Nv ,
pressure is difficult due to variation of soil conditions and uncerlainty in construction．Support pressure should be m4gU*?
controlled SO that it is not SO low as to cause face collapse and not SO high as to induce ground hogging．Numerical G+yL;G/
simulation is employed to study how the soil parameter and ground water affect the support pressure，and to give the Zu=kT}aGg
proper support pressure at the excavation face in a case study． \|Qb[{<:,
Keywords：shield tunnel；excavati‘on face；numerical solution；support pressure
