Civil and Building Engineering.

The geologist uses a variety of tools to study the earth, perhaps to depths of hundreds of meters, to gain information on a variety of matters, such as the occurrence of petroleum products, the prediction of earthquakes, and the science of the earth. While these matters are of general interest, the engineering
geologist has a particular interest in near-surface geology, principally to guide the subsurface investigation and planning for construction.

The work of the engineering geologist is crucial in the design and construction of dams and major earthworks and is somewhat less important in the design of foundations. The design of the subsurface investigation for a
project begins with a study of the geologic process that resulted in the creation of the soil and rock at the site. The investigation continues, with near-surface geology playing an important role as the final design of the foundation is made and the completed foundation is observed.

An interesting fact is that the late Dr. Karl Terzaghi, the father of modern geotechnical engineering, began his studies of soil with a study of geology and maintained an intense interest in geology throughout his career. An early paper (Terzaghi, 1913) dealt with karst geology and a later one with the limitations of subsurface investigations in revealing all information of significance (Terzaghi, 1929). In a paper about Terzaghi’s method of working,

Bjerrum (1960) wrote: ‘‘The intimate knowledge of the geology of the whole area is as necessary for his work as the subsoil exploration which follows.’’

There is good reason to believe that Terzaghi’s method of working remains a valid guideline.

Presented here are brief discussions of geologic processes that affect the character of near-surface soils, availability of information on geology to the engineer, an example of the geology of a selected area, and geologic features that affect subsurface investigations and designs.