Fractures are ubiquitous in geological formations which are home to various subsurface resources and engineering systems. In applications as CO2 storage and geothermal energy extraction, deformation of the porous medium is often inevitable under typical operating condititions. For geothermal applications, such are in fact typically used to enhance the permeability of the system and thus increase eficacy, yet also increase the potential for induced seismicty. In other words, fractures both significantly affect fluid flow as well as they can weaken the structural stability of the entire system. Thus, accurate numerical modeling is of increased importance to ensure viable and safe operation. Mathematical models for flow in deformable fractured porous media [4] are typically built on poromechanics models, coupling flow and deformation in a multiphysics fashion. Additional contact conditions at fractures model non-penetration and frictional contact. Resolving such conditions results in a model with variational structure which has a non-smooth and non-linear character; the actual active contact area is part of the unknown. The resulting system is commonly solved by a non-smooth Newton method [4], close to a primal-dual active set method [2]. Yet, due to the strong nonlinearities, robustness and convergence issues may arise. In this talk, we discuss strategies, aiming at improved stability at the cost of mere linear convergence, based on iterative coupling [3] and stabilization [1] techniques which have proven successful for parts of the considered model. REFERENCES [1] J. W. Both, M. Borregales, J. M. Nordbotten, K. Kumar, and F. A. Radu. Robust fixed stress splitting for biot’s equations in heterogeneous media. Applied Mathematics Letters, 68:101–108, 2017. [2] S. Hüeber, G. Stadler, and B. I. Wohlmuth. A primal-dual active set algorithm for three-dimensional contact problems with coulomb friction. SIAM Journal on Scientific Computing, 30(2):572–596, 2008. [3] K. Ito and K. Kunisch. Augmented lagrangian methods for nonsmooth, convex optimization in hilbert spaces. Nonlinear Analysis: Theory, Methods & Applications, 41(5-6):591–616, 2000. [4] I. Stefansson, I. Berre, and E. Keilegavlen. A fully coupled numerical model of thermo-hydro-mechanical processes and fracture contact mechanics in porous media. Computer Methods in Applied Mechanics and Engineering, 386:114122, 2021.