A New Physical Model for Studying Flow Direction and Other Influencing Parameters on the Internal Erosion of Soils

Abstract

In internal erosion studies, the effect of seepage flow direction in soil and soil layers has received little attention. However, in geotechnical structures, such as earth dams or even natural deposits, the flow may not be perpendicular to the layers or in line with the gravity. Hence, in this article, a special physical model is introduced with both the possibility of changing the flow angles relative to the direction of gravity and the possibility of studying heterogeneous specimens in internal erosion. In addition, the effect of flow direction, inclination of layers, and plasticity index on the internal erosion (suffusion) of gap-graded soil with two types of fines, bentonite and rock flour, has been tested and analyzed. Additionally, a new method for specimen preparation of the gap-grading soils called the “ideal moisture content method” has been presented. Based on the results, the greater the angle of the flow vector is in relation to the direction of gravity; the occurrence and continuation of erosion takes place in higher gradients. Furthermore, in general, in the case of layers perpendicular to the flow, the rate of flow discharge and amount of the eroded particles in the same conditions are less than those of layers parallel with the flow. Moreover, layer direction affects the shape of pipes created because of the erosion.