Fundamentals of Engineering Design
188.8.131.52 Stability of Steep Slopes
Currently, the Thorne (1988) model is used to determine the stability of steep stream bank slopes.
Slopes greater then 60 degrees to the horizontal are classified as steep.
The Darby and Thorne (1996a,b) model utilizes a similar interface as the DECBank program, in
that it reads and interprets HEC-2 input data files to develop the required bank heights and angles for
stability calculations. Unlike the DECBank, the Darby and Thorne (1996a,b) model can directly account
for pore and confining water pressures, in the determination of the factor of safety of a stream bank. The
Darby and Thorne (1996a,b) model performs all stability calculations in Metric units, so the user is required
to convert or obtain singular or average values of cohesion and unit weight to or in Metric units.