Constructing dams by direct blaring has become widespread in the USSR. The main advantages of this method is the reduction in construction time and labor. The quality of dams constructed by blasting has not been examined in detail heretofore and, therefore, in this atticle on the basis of the authors" investigations and data obtained by other investigators an attempt is made to analyze the quality of these darns and to reveal factors affect-Lug it.The main indices givetning the quality of such dams are the patticle-size distribution, density, and permeability coefficient. Other indices such as the angle of friction, deformability, etc., are their derivatives and can be determined under laboratory conditions. The percolation properties also depend directly on the density and the patticle-size distn'bution, but presently there are no sufficiently reliable calculation methods for establishing this relation and laboratory percolation experiments are too arbitaty, therefore for crucial structures the permeability coefficient is usually also a control index and is determined under full-scale conditions.The experience of world and Soviet darn construction shows that the requirements imposed on the particlesize distribution of the rock mass of the shoulders, which are the main elements on which depend the strength and deformabiiity of dams, are constantly and successively being changed. The development of civil engineering and and increase in the height of dams being constructed cause this.