This dissertation forms part of a larger research field which deals with using seismic monitoring systems to better understand the behavior of natural rock slope appealing to the laboratory and in-situ experiments and the numerical simulation. For this purpose, a small scale rock mass, former instrumented from the geo-hydro-mechanical point of view, bas been chosen for installing a seismic monitoring system. ln this site, it is possible to easily induce a known hydraulic charging and to measure displacements and pressures in many meaningful points. The results of the in-situ experiments highlight the existence of micro-seismicity induced by a variation of water pressures and the repetitiveness either of the hydro-mechanical and micro-seismic behavior. From results, it bas been hypothesized that the micro-seismic activity onsets when water pressure increases in less permeable zones. The Finite Elements numerical modeling of the site allows to calculate the stress variations due to hydraulic charging and to assess if stress variations could generate seismic sources. Series of cores have been taken from the site in order to tested rock material and rock fractures in laboratory, associated with acoustic emissions. lt results that little stress variations due to water pressure, calculated for the site, do not explain the micro-seismicity observed in laboratory. A micro-mechanical model using Boundary Elements Method (Displacements Discontinuity Method) which simulates the hydro-mechanical behaviour of rock joints sample under normal compression is proposed taking into account the joint topography. Results confirm the laboratory observations and show that the hydrostatic charging can induce instabilities, when contact areas open, comparable to the ill-situ micro-seismicity.