The action of research focus on the untreated fine behavior of the soil constructions, and the the hydromechanical not saturated coupling. This domain of behavior is not taken into account in the design of such constructions, it is not teached in schools and no reference guide dealing with this problem exists. The most used professionnal guide GTR indicates the conditions of use of materials (traficability and compaction). Nevertheless, the problems of stability of the constructions in fine soils, their breath (frost / unfrost, moistening, infiltration / evaporation, capillary) and deformations associated during the construction or after the reception of the construction are not approached. The analysis of the pathologies on the existing soils constructions shows that the majority of the disorders are connected to unknown hydric conditions into fine soil constructions.. The TerreDurable project provides a guide needed by profession and gives a methodology of design which is founded on on scientific data and on experience of the practitioners. The objective of this project is to propose a methodology of study for the new soil constructions but also for the repair of the existing constructions which present disorders connected to the unsaturation phenomena. The project should be labelled by the center of excellence INDURA