Confluent biological tissues can be thought of as active multicellular systems: they consume energy (ATP) to generate motion or change their conformation. This activity affects the pressure that a tissue exerts on a wall in a sophisticated way. Biological cells are much more complex than synthetic colloidal particles: they can deform, fluctuate, adapt, communicate, in ways that are inaccessible to synthetic units. In this internship, we want to explore numerically how the activity affects the pressure exerted by an active cellular system on a wall. Different models of active cells will be proposed and compared. A one-dimensional theoretical approach can also be envisaged. This study will also address the question of how to measure non-perturbatively the pressure in a tissue. In recent years, deformable particles have been used as probes for measuring stress within confluent biological tissues. However, it is known that the pressure is generally not a state function for active fluids, implying that the force exerted by an active fluid on a wall may depend on their specific interaction.