The paper presents a critical review of the state of the art of geotechnical engineering of natural slopes, cuts and fills in soil. Topics which are covered include the pre and post failure mechanics at the micro and macro scale, including discussion of contractant and other strain weakening soils, creep, progressive and retrogressive failure and fissured clays. Geotechnical investigation requirements and methods for analysis of stability and deformations, and for analysis of post failure velocity and travel distance are reviewed. It is concluded that many slope instability hazards may be managed by traditional factor of safety methods, but that it is important that the post failure behaviour be considered. Observational, and risk assessment methods may be more appropriate than the traditional methods in many cases.
This paper sets out to present a critical review of the state of the art of geotechnical engineering of natural slopes, cuts and fills in soil. This includes site characterization, including the geology and hydrogeology, the establishment of the material properties and pore pressures, the mechanics of sliding at the micro and macro scale, analysis of stability, deformations pre and post failure, and management of the slope hazard. The emphasis is on practical issues, and the integration of engineering geology, hydrogeology, rock and soil mechanics. We will be seeking to demonstrate that it is now practical to quantify the potential post failure deformations sufficiently well that their assessment should be part of any geotechnical assessment of a slope. In this way, the engineering of a slope can be linked to the consequences of failure, allowing better management of the risks. We have also emphasized those situations which are not well modelled by conventional effective stress analyses.