Engineering and Construction

INTRODUCTION
Geotechnical earthquake engineering can be defined as that subspecialty within the field of geotechnical engineering that deals with the design and construction of projects in order to resist the effects of earthquakes. Geotechnical earthquake engineering requires an understanding of basic geotechnical principles as well as an understanding of geology, seismology, and earthquake engineering. In a broad sense,  seismology can be defined as the study of earthquakes. This would include the internal behavior of the earth and the nature of seismic waves generated by the earthquake.

For geotechnical earthquake engineering of soils and foundations, the types of activities that may need to be performed by the geotechnical engineer include the following:

• Subsurface exploration for geotechnical earthquake engineering, i.e., the screening investigation and the quantitative evaluation.
• Total stress and effective stress analyses for geotechnical earthquake engineering
• Bearing capacity analyses for geotechnical earthquake engineering
• For the design earthquake, determining the peak ground acceleration and magnitude of the earthquake
• Investigating the possibility of liquefaction at the site
• Investigating the stability of slopes for the additional forces imposed during the design earthquake
• Calculating the settlement of the foundation caused by the design earthquake
• Performing calculations to assess the effect of the earthquake on retaining walls
• Considering foundation alternatives to mitigate the effects of earthquakes

In terms of the accuracy of the calculations used to determine the earthquake induced soil move-
ment, Tokimatsu and Seed (1984) conclude:

It should be recognized that, even under static loading conditions, the error associated with the estimation of settlement is on the order of ±25 to 50%. It is therefore reasonable to expect less accuracy in predicting settlements for the more complicated conditions associated with earthquake loading.... In the application of the methods, it is essential to check that the final results are reasonable in the light of available experience.