Abstract: The high cost of urban space has significantly increased the demand for tunnels in big urban centers. In such areas, settlement induced by the tunnel excavation may cause serious damage to nearby structures. Therefore, it is necessary to investigate effective means of controlling tunnel-induced settlements. In many countries, tunnel in soil and rock mass are constructed using new Austrian tunneling method (NATM) for its flexibility to adapt to different ground conditions and use of simple equipments. Ago, tunnel designs by NATM are generally based on empirical methods taking into account local experiences. But this method is said to be observational and cannot illustrate the construction process and the stress and strain changing. So that, with the developing of PC and numerical method, using FEM and other method have been utilized in geotechnical engineering. At first, the paper shows the principles of NATM, and illustrating the two key: excavating unloading node force on the tunnel boundary and constructing steps. And on the base of above illustration, utilizing finite element code ABAQUS analyzing and modeling a tunnel. From obtained results, it is shown that the finite element method can model tunnel constructing process reasonably.

Key words: rock mechanics, NATM, FEM, ABAQUS