In recent years, the authors and co-workers have developed a 3D finite element model for coupled two-phase thermo-hydro-mechanical problems (THGM) in fractured rock masses. In this model, zero-thickness interface elements are used to explicitly represent the THGM behaviour of discontinuities (fractures, joints, bedding planes, etc.) in the rock mass. The model has been implemented in the finite element code DRAC5, which is equipped with fracture-based interface elements and MPI parallel capabilities [1]. The governing equations consider two fluid phases (liquid and gas) and two species (water and gas). The liquid phase includes only water species, while the gas phase includes water vapour and gas species. The parameters of the liquid retention and relative permeability curves assigned to the interface elements (e.g. gas entry value, residual liquid saturation) are updated with the mechanical aperture of the discontinuity. The model was introduced in a previous paper with three, single-element verification examples demonstrating the model capabilities [2]. In the present paper, new multi-element application examples are presented a “sandwich” domain composed of two horizontal layers of unsaturated porous medium separated by a discontinuity. Three cases with different boundary conditions are investigated, including an analysis of the sensitivity of the results to the discontinuity opening. The results show the ability of the model to realistically reproduce the essential role of discontinuities in the overall behaviour of a rock mass. REFERENCES [1] Garolera, D., “Zero-thickness interface elements in petroleum geomechanics: sand production and hydraulic fracture” Dr. Thesis, UPC (2017). [2] L. Barandiarán, J. Liaudat, C. M. López and I. Carol. Numerical modelling of two-phase flow in fractured rock masses using zero-thickness interface elements. Presentations and videos to 16th International Conference on Computational Plasticity (COMPLAS 2021) 2021. Pages 1-12. https://www.scipedia.com/sj/complas2021