The underwater slopes of hydraulic earth structures subjected to the effect of a longitudinal flow are usually protected by a stone revetment obtained by filling stone into the water with subsequent leveling.The shortcomings of this method are: the large consumption of stone, high labor intensity, long construction time, and poor quality and reliability of the revetment.The method of self-placment of stone is free of these shortcomings [i].The essence of the method of self-placement of stone is that in the low-flow period an additional shoulder of soil (sand) with a horizontal berm above the water level is filled to the design outline.Material intended for revetting the slope is placed on the berm. During the flood the revetting material, as the slope and berm are eroded, gradually moves to the slope, forming the revetment.The method of self-placement has been rather thoroughly investigated under laboratory conditions [2]. The main purpose of the experiments was to establish the mechanism of formation of a revetment by self-placement of stone. A generalization of the experimental results made it possible to compile a scheme of formation of the revetment by self-placement of stone ( Fig. i). At flow velocities exceeding the nonerodible for sand, the slope begins to be eroded, but more intensely at the base, and its steepness gradually increases.Erosion occurs with the formation of mobile ridges, collapse of the slope does not occur. On reaching a steepness m~ = 2.5, individual stones begin to move down slope, and each stone rolls into a pit forming at the bottom near it. As the number of stones increases on the slope, the rate of erosion decreases and the height of the ridges decreases.When m 2 = 2, mass movement of the stones downslope begins.The stones, moving downward, wobble, turn, but do not turn over. In the presence of a nonerodible bottom, a part of the stones is placed on the bottom.A steepness m 2 = 2 is preserved until complete protection of slope by stones. Stabilization of the slope occurs as a result of mutual adjustment of individual stones so that the sucking of sand from under ends. The revetted slope remains stable with increase of flow velocity to the noneroding for the revetting material on the slope.Gravel with a size of 3-7 mm was used in the experiments as a model of stone. The thickness of the revetment layer in all experiments was equal to the size of one particle over the entire slope. The maximum density of gravel on the slope was obtained with its six-layer thickness in the fill on the berm.With a two-layer thickness of the gravel layer, the slope is not protected at all.The ratio of the density of placement in the fill on the berm and density of placement on the slope, called the self-placement coefficient, in the experiments reaches k s = 1.5. For sphericla particles the theoretical value k s = 1.2. It is obvious that for material with alarge degree of nonuniformity of the fractional composition, k s = i.O.Experiments completely confirmed the calculation scheme of self-placement (Fig....