Abstarct: One of the most important issues encountered by the dam and geotechnical engineers in the field of earth and earth-rockfill dams is the slope stability analysis and the failure surface analysis and also the procedure of determining the slopes failure. The most common methods of slopes stability analysis are the limit equilibrium methods and the finite element method which can be calculated by manual calculation and computer programs such as slope/w and plaxis are utilized for this purpose and also for the determination of the critical failure surface but the plotting and determination of these failure surfaces which are known as the slip arc have not been performed yet in an actual and practical manner. In this thesis, the plotting and determination of these slip arcs have been accomplished in a real and practical way by a modern method during the drilling of the reconnaissance trench. In addition, using the liquid colored indicator and also the calculation of the slopes stability coefficient by it have been considered in a completely visual and accurate manner to prepare the most appropriate design for the restoration of Shurak earth-rockfill dam in Shirvan which has experienced a damage of slip arc type. In the presented restoration design for the reoperation of the mentioned dam, the maximum height considered for drawing off the crown of Shurak dam is 5 to 6 meters. However, this value has been obtained at least equal to 10 meters according to the information yielded from the instrument prepared in the dam body in the restoration design. The results of this research about the stability factor and also the visual modeling of the slip arc have been compared to and validated by theoretical methods including mathematical calculations and also Slope/w simulation software.