טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentRobert Shukha
SubjectEffect of a Nonlinear Strength Law on Static and Pseudo-
Static Slope Stability Problems
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Emeritus Baker Rafael (Deceased)


Abstract

Most conventional slope stability calculations are based on the linear Mohr-Coulomb failure criterion. However, a substantial amount of experimental evidence suggests that failure criteria of many soils are not linear, particularly in the range of small normal stresses. This departure from linearity is significant for slope stability calculations since for a wide range of practical stability problems, critical slip surfaces are shallow and normal stresses acting on such surfaces are small.

The main purpose of the present work was to study the effect off strength envelope's nonlinearity on slope stability calculations, and this is done by two different approaches: 1) Conventional Limiting Equilibrium (L-E) and 2) Strength Reduction Method (S-R) which has been implemented with finite difference program "FLAC- Fast Lagrangian Analysis of Continua".

Extensive comparison has been studied in terms of both critical heights and safety factors between the two envelopes. The main results following from this comparison are: When there is a significant mismatch between the ranges of experimental and relevant normal stresses, results obtained based on the two strength criteria are very different, with the non-linear criterion providing usually more conservative results. Consequently it appears justified to use the non-linear criterion in order to insure safe design. Another aspect which has been studied in this research is the effect of the Pseudo-Static forces on slope stability and it presents a complete design chart for pseudo-static analysis of homogeneous slopes based on a rigorous formulation of the slope stability problem.