During the construction of shie ld tunnels，support pressure is usually applied at the work face to prevent
excessive tunneling—induced soil movement or collapse．However，the selection and control of appropriate support
pressure is difficult due to variation of soil conditions and uncerlainty in construction．Support pressure should be
controlled SO that it is not SO low as to cause face collapse and not SO high as to induce ground hogging．Numerical
simulation is employed to study how the soil parameter and ground water affect the support pressure，and to give the
proper support pressure at the excavation face in a case study．
Keywords：shield tunnel；excavati‘on face；numerical solution；support pressure
