Geotechnical HOME

Steve Hencher - 455 pages - Language: English - Publisher: CRC Press; 2nd Edition (November, 2017).

Practical Engineering Geology provides an introduction to the way projects are managed, designed and constructed, and how the engineering geologist can contribute to cost- effective and safe project achievement. The need for a holistic view of geological materials, from soil to rock, and of geological history is emphasised.

Chapters address key aspects of: Geology for engineering and ground modelling + Site investigation and testing of geological materials + Geotechnical parameters + Design of slopes, tunnels, foundations, and other engineering structures + Identifying hazards + Avoiding unexpected ground conditions.

This second edition includes a new chapter on environmental issues covering hydrogeology, considerations of climate change, earthquakes, and more. All chapters have been updated, with extensively revised figures throughout and several new case studies of unexpected ground conditions. The book will support practising engineering geologists and geotechnical engineers, as well as MSc level students of engineering geology and other geotechnical subjects.

The major subdivisions of geological time is into eras, periods, and epochs. These separations are based on fossil evidence and on extinctions. For example, the Mesozoic era ended with an abrupt termination of the dinosaurs, now usually attributed to a severe climate change following the impact of a meteor. Breaks in deposition of sediments create erosional surface ‘‘unconformities.’’

The ‘‘Paleozoic era’’ literally means ‘‘ancient-life-time’’ and was dominated by invertebrates including many varieties of now-extinct shellfish. The ‘‘Mesozoic era,’’ or ‘‘middle-life-time,’’ was a time of dinosaurs and the earliest mammals. The ‘‘Cenozoic era,’’ or ‘‘recent-life-time,’’ is dominated by mammals.

Unconformities are very common and subdivide a rock column into ‘‘formations’’ of consistent geological age. ‘‘Formation’’ is not a time designation but a rock designation, and a single formation may incorporate a variety of rock layers. Formations for the most part are identified from fossils, which is very important in exploration drilling for oil.

Radioactive dating depends on constant rates of radioactive decay of certain isotopes, and indicates that the majority of geological time was without life except for single-celled plants, or algae. These rocks generally have been buried under younger rocks and constitute part of the ‘‘basement complex.’’ They may be lumped together in age as ‘‘pre-Cambrian,’’ which means that they originated prior to the earliest, Cambrian, period of the Paleozoic era. Granitic shield areas often are referred to as ‘‘pre-Cambrian shield.’’