1 Aims and overview ¿ slopes, geology and materials 1.1 Introduction 1.2 Overview of recent developments and trends 1.2.1 Increasing frequency and impact of disasters from slope failures and landslides 1.2.2 Climate change, global warming and sea level rise 1.2.

3 Built slopes ¿ lessons from the catastrophic impacts of Hurricane Katrina 1.2.4 New developments related to slope analysis 1.2.5 Importance of probabilistic analysis 1.2.6 GIS-based methods and analyses 1.2.

7 Assessments concerning very large landslides 1.2.8 Landslide frequency related to magnitude 1.2.9 Assessing regional landslide susceptibility and hazard 1.2.10 Development and use of slope stability software 1.2.

11 Need to strengthen the fundamentals of geomechanics and slope analysis 1.3 Main aim and scope of this book 1.4 Aims of geotechnical slope analysis 1.5 Natural slopes ¿ regional and site-specific analyses 1.6 Natural slopes ¿ factors affecting stability 1.7 Built slopes, unreinforced and reinforced 1.7.1 Unreinforced slopes 1.

7.2 Reinforced slopes 1.8 Geomorphology and slopes 1.9 Types of slope movement and landslides 1.9.1 Processes and types of slope movement 1.9.2 Pre-failure and post-failure movements 1.

9.3 Failures of slopes in poorly compacted fill 1.9.4 Some observed data concerning magnitude of movements in soil and rock slopes 1.9.5 Rainfall as a triggering factor for slope failures or for the occurrence of landslides 1.9.6 Available methods for seepage analysis 1.

10 Geology and slopes 1.10.1 Fabric 1.10.2 Geological structure 1.10.3 Geological structure and tendency of slope movement 1.10.

4 Ground water 1.10.5 Seismic effects 1.10.6 Ground stresses or ¿initial¿ stresses 1.10.7 Weathering 1.10.

8 Previous landslide activity 1.11 The nature of soils 1.12 The nature of rocks Appendix to chapter 1 2 Basic geotechnical concepts 2.1 Introduction 2.2 Stress and strain 2.2.1 Elastic (recoverable) stresses and strains in soil and rock 2.2.

2 Irrecoverable strains in soil and rock 2.3 The principle of effective stress in soil and rock 2.3.1 Saturated soil 2.3.2 Unsaturated soil 2.3.3 Different types and sources of pore water pressure 2.

3.4 Reservoir filling and artesian pressures ¿ an example, the 1963 Vaiont slide 2.4 Shear strength of soils 2.4.1 Dry or saturated soils 2.4.2 Unsaturated soils 2.4.

3 Slope failures involving unsaturated soil slopes 2.4.4 Factors influencing shear strength parameters 2.4.5 Measurement of shear strength under different drainage conditions 2.4.6 Peak, ultimate and residual shear strength 2.4.

7 Factors influencing residual shear strength 2.4.8 Undrained strength of fissured clays 2.5 Mohr-Coulomb criterion in terms of principal stresses and stress path concept 2.5.1 Stress paths 2.5.2 Failure plane inclination and intermediate principal stress 2.

5.3 Coulomb failure criterion for compression and extension tests 2.6 Shear strength of rocks 2.6.1 A rock mass as a discontinuum 2.6.2 Example of the importance of discontinuities in rock ¿ the occurrence of catastrophic landslides 2.6.

3 Griffith theory of rock fracture 2.6.4 Shear failure along rough discontinuity 2.6.5 Continuity of jointing and actual area of contact 2.6.6 Curved strength envelopes 2.6.

7 Strength of filled discontinuities 2.6.8 Shear strength of closely jointed or fractured rock 2.6.9 Determination of shear strength 2.7 Plasticity and related concepts 2.8 Excess pore water pressures 2.9 Relationships between drained and undrained strength of cohesive soils 2.

9.1 Unique w-p-q relationships at peak and ultimate strength 2.9.2 Undrained strength and pore pressure parameterat failure 2.9.3 Relative magnitude of drained and undrained strength 2.9.4 "¿ ¿¿0" concept 2.

9.5 Anisotropy of shear strength 2.10 Progressive failure of slopes 2.11 Residual strength and other factors in progressive failure 2.12 Progressive failure and the stress field 2.13 Numerical examples 3 Performance indicators and basic probability concepts 3.1 Introduction and scope 3.1.

1 Preliminary decisions concerning type of analysis 3.1.2 Choice of performance indicators 3.1.3 Contents of this chapter 3.2 Deterministic approach 3.2.1 Global and local factors of safety 3.

2.2 Critical seismic coefficient as alternative to factor of safety 3.2.3 Progressive failure and system aspects 3.2.4 Performance indicators for stress-deformation analyses 3.2.5 Threshold or allowable values of factor of safety 3.

3 Probabilistic approach 3.3.1 Uncertainties and the probabilistic framework 3.3.2 Systematic uncertainties and natural variability of geotechnical parameters 3.4 Reliability index, probability of failure and probability of success (reliability) 3.5 Considering thresholds ¿ minimum reliability index, maximum probability of failure 3.6 Spatial, temporal and system aspects 3.

7 Susceptibility, hazard and risk 3.8 Further comments on geotechnical uncertainties 3.8.1 Introduction 3.8.2 Basic statistical parameters 3.8.3 Variability of soil properties and errors 3.

9 Variance of F for simple slope problems 3.10 Using probabilistic analysis 3.10.1 Requirements and limitations: discussions during early phase of development 3.10.2 Example of a probabilistic slope study, De Mello (1977) 3.10.3 Errors and probability of failure, Wu and Kraft (1970) Appendix I to chapter 3 C3I.

1 Axioms and rules of probability C3I.2 Conditional probability and statistical independence C3I.3 Total probability and Bayes¿ theorem C3I.4 Random variables and probability distributions C3I.5 Moments of a random variable C3I.6 The normal distribution C3I.6.1 The standard normal variate C3I.

6.2 Application of standard normal variate C3I.7 Logarithmic normal distribution C3I.8 Joint distribution, covariance and correlation C3I.9 Moments of functions of random variables C3I.9.1 Sum of variates x1, x2 etc. C3I.

9.2 Product of independent variates x1, x2, x3, etc. C3I.9.3 First order approximation for general functions Appendix II to chapter 3 C3II.1 Equations for a capacity ¿ demand model (after Harr, 1977) C3II.1.1 Safety margin and factor of safety C3II.

1.2 Defining probability of failure and reliability C3II.1.3 Probability of failure with normal distribution C3II.1.4 Probability of failure with lognormal distribution C3II.1.5 Safety margin required for given reliability Appendix III to chapter 3 4 Limit equilibrium methods I ¿ planar failure surfaces 4.

1 Introduction to limit equilibrium methods 4.1.1 Methods considered in chapters 4 and 5 4.1.2 Scope of limit equilibrium studies 4.1.3 The concept of slip surfaces 4.1.

4 Defining factor of safety as per concept of limit equilibrium 4.1.5 Alternatives to conventional safety factor 4.1.6 Saturated and unsaturated soil slopes 4.2 Infinite slopes in cohesionless soils 4.2.1 Dry cohesionless soil 4.

2.2 Submerged cohesionless soil 4.2.3 Cohesionless soil with seepage parallel to slope 4.2.4 Rapid drawdown of water level in a slope of cohesionless soil 4.3 Infinite slopes in cohesive soil 4.3.

1 Seepage through a slope ¿ simple cases 4.3.2 Rapid drawdown of water level in a slope of cohesive soil 4.4 Ultimate inclination of natural slopes 4.5 Vertical cuts in cohesive material 4.5.1 Unsupported height of a vertical cut and tension crack depth 4.5.

2 Tension crack depth for use in stability analysis 4.6 Plane failure in rock slopes 4.7 Plane failure with water in tension crack 4.7.1 Conventional analysis 4.7.2 Alternative ways of defining F 4.8 Interpretation of strength data for use in stability calculations 4.

9 Two-dimensional sliding along one of two joint sets 4.10 Continuity of jointing 4.11 Wedge method or sliding block method of two-dimensional analysis 4.11.1 Bi-planar slip surface 4.11.2 Tri-planar sliding surface 4.12 Failure of three-dimensional wedge 4.

13 Layered natural deposits and the effect of water pressure 4.13.1 Interbedded sand and clay layers 4.13.2 Interbedded sandstones and shales 4.14 Earth dams ¿ plane failure analyses 4.14.1 Introduction 4.

14.2 Simple sliding block analysis 4.14.3 Hydraulic fill dam 4.15 Slurry trench stability 4.15.1 Cohesionless soil 4.15.

2 Cohesive soil ¿ soft clay 5 Limit equilibrium methods II ¿ general slip surfaces and beyond critical equilibrium 5.1 Introduction and scope 5.1.1 Drainage conditions ¿ choice between effective stress and total stress analysis 5.1.2 Shapes of slip surfaces