Deformation and Noneroding Velocities in Channels Composed of Inequigranular Soils

Abstract

The noneroding velocities in channels composed of inequigranular soils that are determined with consideration of the formation of a natural channel bed armor layer are overstated in the construction codes and regulations (SNiP-06.03.85). It is suggested to use in calculations the noneroding velocities determined with the formation of natural armoring and to calculate the depth of scouring and diameter of armor by the method proposed herein or A. V. Magomedova’s method. This article examines deformations of a model canal channel in inequigranular, noncohesive, rather coarse-grained soils with an average particle diameter greater than 0.55 mm, in which the formation of natural armor is possible at velocities insignificantly exceeding the noneroding. A calculation scheme is proposed. It is suggested to consider channel scour normal to the slopes. It is suggested to estimate the time of deformations with the use of the probabilistic formula based on K. I. Rossinksii’s model for bedload discharge. To determine the diameter of the natural armor and scour depth, a calculation method is proposed which gives values close to those obtained in experiments.