The majority of slope stability analyses performed in practice still use traditional limit equilibrium approaches involving methods of slices that have remained essentially unchanged for decades. This was not the outcome envisaged when Whitman & Bailey (1967) set criteria for the then emerging methods to become readily accessible to all engineers. The finite element method represents a powerful alternative approach for slope stability analysis which is accurate, versatile and requires fewer a priori assumptions, especially, regarding the failure mechanism. Slope failure in the finite element model occurs 'naturally' through the zones in which the shear strength of the soil is insufficient to resist the shear stresses. The paper describes several examples of finite element slope stability analysis with comparison against other solution methods, including the influence of a free surface on slope and dam stability. Graphical output is included to illustrate deformations and mechanisms of failure. It is argue...

Slope stability analysis by finite elements

A study on the influence of the plasticity index (PI) on the cyclic stress‐strain parameters of saturated soils needed for site‐response evaluations and seismic microzonation is presented. Ready‐to‐use charts are included, showing the effect of PI on the location of the modulus reduction curve G/Gmax versus cyclic shear strain γc, and on the material damping ratio λ versus γc curve. The charts are based on experimental data from 16 publications encompassing normally and overconsolidated clays (OCR=1-15), as well as sands. It is shown that PI is the main factor controlling G/Gmax and λ for a wide variety of soils; if for a given γc PI increases, G/Gmax rises and λ is reduced. Similar evidence is presented showing the influence of PI on the rate of modulus degradation with the number of cycles in normally consolidated clays. It is concluded that soils with higher plasticity tend to have a more linear cyclic stress‐strain response at small strains and to degrade less at larger γc than soils with a lower PI. ...

Effect of Soil Plasticity on Cyclic Response

INTRODUCTION For slopes, the factor of safety F is traditionally de®ned as the ratio of the actual soil shear strength to the minimum shear strength required to prevent failure (Bishop, 1955). As Duncan (1996) points out, F is the factor by which the soil shear strength must be divided to bring the slope to the verge of failure. Since it is de®ned as a shear strength reduction factor, an obvious way of computing F with a ®nite element or ®nite difference program is simply to reduce the soil shear strength until collapse occurs. The resulting factor of safety is the ratio of the soil's actual shear strength to the reduced shear strength at failure. This `shear strength reduction technique' was used as early as 1975 by Zienkiewicz et al. (1975), and has since been applied by Naylor (1982), Donald & Giam (1988), Matsui & San (1992), Ugai (1989), Ugai & Leshchinsky (1995) and others. The shear strength reduction technique has a number of advantages over the method of slices for slope stability analysis. Most importantly, the critical failure surface is found automatically. Application of the technique has been limited in the past due to the long computer run times required. But with the increasing speed of desktop computers, the technique is becoming a reasonable alternative to the method of slices, and is being used increasingly in engineering practice. However, there has been little investigation of the accuracy of the technique. In this paper, factors of safety obtained with the shear strength reduction technique are compared to limit analysis solutions for a homogeneous embankment.

Slope stability analysis by strength reduction

Finite element slope stability analysis by shear strength reduction technique

Two-dimensional slope stability analysis by limit equilibrium and strength reduction methods

https://www.jstage.jst.go.jp/article/sandf1972/15/4/15_4_43/_pdf

Methods to estimate lateral force acting on stabilizing piles

Design Method for Stabilizing Piles Against Landslide—One Row of Piles

Effects of some factors on the excess pore pressure are clarified, followed by an examination of the reliability of cyclic pore pressure measurement, the normalization of stresses, and the failure due to cyclic loading of clays. An equation of the residual excess pore pressure, represented as a function of both the maximum cyclic shear strain and the overconsolidation ratio, is deduced. An overconsolidated state due to the cyclic stress-strain history is similar in strength to one due to the ordinary overconsolidation history. In spite of the temporary loss in strength and deformation modulus immediately after cyclic loading, the dissipation of pore pressures leads to higher strength and deformation modulus than the initial ones before cyclic loading. It is implied that cyclic stress-strain history can be one of the factors causing natural ground to become lightly overconsolidated.

Cyclic Stress-Strain History and Shear Characteristics of Clay

https://www.jstage.jst.go.jp/article/sandf1972/22/1/22_1_1/_pdf

Tamotsu Matsui

Papers

Finite element slope stability analysis by shear strength reduction technique

Methods to estimate lateral force acting on stabilizing piles

Design Method for Stabilizing Piles Against Landslide—One Row of Piles

Cyclic Stress-Strain History and Shear Characteristics of Clay

Extended Design Method for Multi-Row Stabilizing Piles against Landslide