The range of problems that geotechnical engineers must face is increasing in scope and complexity. Some examples are the collapse of unsaturated soils, foundations on expansive clays, tunnelling in sulphate bearing materials, control of subsidence due to oil or gas extraction, and containment of toxic or hazardous waste. In addition, potential climate change may pose new problems in areas such as slope stability or permafrost thawing as well as placing new emphasis on topics such as radioactive waste disposal or deep CO2 sequestration. Classical saturated Soil Mechanics is often insufficient to provide the understanding and tools to tackle these issues effectively.
In the lecture, a number of developments incorporating the effects of new phenomena and new variables on the behaviour of soils will be described and discussed. Recent developments in Unsaturated Soil Mechanics will be reviewed first. It will be shown that they provide a consistent framework for understanding the engineering behaviour of unsaturated soils and the effects of suction and moisture changes. Building on those developments, soil behaviour is further explored by considering the effect of high and low temperatures as well as of chemical variables. The resulting generalised view of soil behaviour is then applied in the analysis of field situations.
The lecture will present documented case histories that demonstrate the relevance and implications of the developments described for geotechnical engineering practice.
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