This paper presents a numerical analysis of swelling deformations in the Pfaendertunnel near Bregenz/Austria, which is a well-known example for swelling in claystones. The constitutive model used in this study employs a semi-logarithmic reduction of swelling strains with stress level and exponential convergence with final swelling strains over time. Input swelling parameters for the analysis were derived from laboratory swelling tests. Due to the wide range of experimental results, upper and lower bounds of swelling parameters were used in the analysis. Calculated invert heave was in particular sensitive to the choice of teh maximum swelling pressure, which governs both the swelling strain at stress point level and the size of the swellling zone below the tunnel invert. Good match with the in-situ measurements was obtained for a maximum swelling pressure of 1500 kPa, which represents the upper edge of the experimental values and is significantly lower than the overburden pressure of about 4900 kPa.