Ardebil field, which has over 1000 hectare fertile land, needs about one billion meter for farming, there for, the significance of using dam and flood water in order to restore the level of water to its initial level is obvious in this field at the time of harvest. Pirtaghis bursts dam is located 70 km from Miyaneh near Pirtaghi village in the study phase. Due to the importance of dam endurance and probable damage caused by dam destruction, it seems necessary to investigate the changes in dam foundation and its bearing capacity in this regard, meeting and allowed bearing capacity of rock foundation are important. Pirtaghi is located in Basaltic tuff zone. This the study embarks on the investigation of the effect of structure construction with different widths and various condition with on displacement values and dam foundation meeting using oftware. In the first step, the structure construction for all widths of 20 to 40 meters in the center of the structure, a lifting was observed because of soft layers of tuff Basaltic in the structure. The highest lifting was obtained for the foundation with 40 meter width which was 39 mm. In the second step, the condition of structure construction and 50 meter high watering were investigation. In this case, the meeting in two sides increased. The lifting of the center decreased as well. However, lifting in the was seen for all widths. In the third step, the condition of dam construction and 100 meter watering were investigation in two phases. The maximum meeting was 42mm wide and the maximum lifting was 32mm for the same width. In the fourth step, the condition of structure construction and its 150 meter watering were investigation in three phases in which, for width of 20 to 30 meters, no lifting was found. For widths of 40 meter, lifting decreased as much as 20mm. But the maximum meeting increased and reached 60mm. These figures were compared with the analytic measurements from classic relations and showed that although, theres a good adjustment between them, in some layers of the ground, theres a noticeable difference in higher levels. This difference indicates that obtained relation from analytic methods are inconsistent