The main purpose of this study is to obtain factor of safety against basal heave in deep excavation using finite element method. Two total stress undrained soil models namely The Mohr Coulomb (=0) model and The Undrained Soft Clay model were used for simulating the excavation cases. These two models have been validated by simulating TNEC excavation case which has well documented data and soil properties. In addition, two failure excavation cases are included for developing reasonable method in obtaining factor of safety number. The Method A is developed based on the shear strength reduction method and the method B is modification of the method A where wall bottom movement and soil bottom heaving behavior take into consideration for obtaining the factor of safety. Both methods can yield reasonable factor of safety depends on soil constitutive model that is used. Based on analyses results, the method A is more compatible with The Undrained Soft Clay model, whereas the method B is more compatible with The Mohr Coulomb (=0) model. Furthermore, increasing wall stiffness not affect too much in increasing excavation stability but increasing of wall penetration depth affects a lot in the increment of excavations stability.

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