Evaluate Reliability of Morgenstern–Price Method in Vertical Excavations

Considering force and moment equilibrium equations simultaneously, Morgenstern–Price’s method is more well mannered than other computational algorithms in slope stability field. On the other hand, because of its simplification, Rankine’s theory has its particular fans in handy calculations and pre-estimations of safe depth in vertical self-stable excavations, classically and academically. To have a comparison of abovementioned methods’ results, in this study, a variety of analyses have been performed using the Morgenstern–Price’s algorithm with SLIDE software in which the cohesion factor of soil changes over a range between 5 and 95 kPa and the inner friction angle is applied less than 40°. The analyses results including self-stable excavation depths between 1 and 8 m and related factors of safety (1–3) are derived and collected in a 90° slope. Moreover, using Rankine’s formula in the same geometry, the determination of safe vertical self-stable excavation depth is performed in various factors of safety. Finally, a relation between two methods is presented as a correlation as well as a reliability evaluation.