Erosão em ravinas e o mecanismo de alargamento lateral

Abstract

Erosion in ravines and its influence on sediment production in river basins are discussed in this dissertation. The mechanism of lateral rupture by rupture, a characteristic step of the development of the ravines, is studied analytically. The analytical procedure is based on a ravine wall stability analysis, which takes into account the variation of soil physical conditions and their resistance with the variation of moisture content imposed by hydrormeteorological conditions. The analysis results in the formulation of equations for the critical conditions of enlargement, for different situations, considering the influence of infiltration, groundwater and the presence of cracks and traction. The critical condition for enlargement in each situation is associated with critical humidity and when it is caused by infiltration the minimum time required for the break to occur is established by the Horton Infiltration curve. For simplicity, the infiltrated slide is calculated to a point representative of average conditions.