This study is a part of a wide multi-scale research based on in situ experiments and laboratory tests. The latest, radial water injections in the centre of the lower joint wall are done at constant normal stress ranging from 0 to 110 MPa and at pressures from 0 to 4 MPa. Four hydromechanical tests have been performed in the L3S laboratory on fractured limestone samples (two diaclase and two bedding plane). The measurement analysis shows a relation between the contact surface variations and the flow values inside the fracture. The hydromechanical modelling performed using 3DEC code can be improved compared with the previous analysis due to the modification of the relation between the joint hydraulic opening and the joint mechanical closure. The gap between simulations and measurements can be related to fracture asperity degradation and turbulent flow that have not been taken into account in the modelling.