The ground water has significant influence on the stability of tunnel face. This report describes the method of evaluating tunnel face stability by a numerical analysis taking the above-mentioned effects into account.  This method applies the finite element analysis (FEA) based on the plastic theory, or the so-called rigid plastic finite element analysis (RPFEA).  In this report, we represent the effect of the ground water when water pressure is applied as a force on the ground. First, we consider the effect of draw-down of the groundwater level by a nonmulti-element model of a two dimensional analysis (2DA). Next, we evaluate the face stability of an actual tunnel by a multi-element model of 2DA.  The subject is a railway tunnel of Tohoku-Shinkansen, constructed in soft ground by the shotcrete tunneling method, or the currently so-called NATM.  The ground water level is very high, while the over burden is small.  The ground near the face is sandy with a clay layer. For this reason, the tunnel face is unstable.  We evaluate the stability of the tunnel face by the proposed method.

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