Engineering and Construction

An engineering geologist is defined as an individual who applies geologic data, principles, and interpretation so that geologic factors affecting planning, design, construction, and maintenance of civil engineering works are properly recognized and utilized (Geologist and Geophysicist Act, 1986). In some areas of the United States, there may be minimal involvement of engineering geologists except for projects involving such items as rock slopes or earthquake fault studies. In other areas of the country, such as California, the geotechnical engineer and engineering geologist usually performs the geotechnical investigations jointly. The majority of geotechnical reports include both engineering and geologic aspects of the project and both the geotechnical engineer and engineering geologist both sign the report. For example, a geotechnical engineering report will usually include an opinion by the geotechnical engineer and engineering geologist on the engineering and geologic adequacy of the site for the proposed development.

Table 1.3 (adapted from Fields of Expertise, undated) presents a summary of the fields of expertise for the engineering geologist and geotechnical engineer, with the last column indicating the areas of overlapping expertise. Note in Table 1.3 that the engineering geologist should have considerable involvement with foundations on rock, field explorations (such as subsurface exploration and surface mapping), groundwater studies, earthquake analysis, and engineering geophysics. Since geologic processes form natural soil deposits, the input of an engineering geologist can be invaluable for nearly all types of foundation engineering projects.

Because the geotechnical engineer and engineering geologist work as a team on most projects, it is important to have an understanding of each individual’s area of responsibility. The area of responsibility is based on education and training. According to the Fields of Expertise (undated), the individual responsibilities are as follows:

Responsibilities of the Engineering Geologist

1. Description of the geologic environment pertaining to the engineering project
2. Description of earth materials, such as their distribution and general physical and chemical characteristics
3. Deduction of the history of pertinent events affecting the earth materials
4. Forecast of future events and conditions that may develop
5. Recommendation of materials for representative sampling and testing
6. Recommendation of ways of handling and treating various earth materials and processes
7. Recommendation or providing criteria for excavation (particularly angle of cut slopes) in materials where engineering testing is inappropriate or where geologic elements control stability
8. Inspection during construction to confirm conditions

Responsibilities of the Geotechnical Engineer

1. Directing and coordinating the team efforts where engineering is a predominant factor
2. Controlling the project in terms of time and money requirements and degree of safety desired
3. Engineering testing and analysis
4. Reviewing and evaluating data, conclusions, and recommendations of the team members
5. Deciding on optimum procedures
6. Developing designs consistent with data and recommendations of team members
7. Inspection during construction to assure compliance
8. Making final judgments on economy and safety matters