Geotechnical Engineering: Big Ideas and Fundamental Understandings
(Below is the text of a letter in response to recent exchanges on the USUCGER e-mail list. USUCGER, The United States Universities Council on Geotechnical Education and Research)
The recent posts regarding content for an introductory course in geotechnical engineering have raised some interesting topics and questions. However, in discussing this topic, we should also consider the breadth of institution types, missions, and students as well as the variation in civil engineering curricula at those institutions (e.g., whether a second course in geotechnical engineering is offered at a strictly undergraduate college). This diversity of institutional settings and curricula means that a one-size-fits-all set of student learning outcomes for an introductory course in geotechnical engineering may not be a realistic goal. That said, the current discussion is immensely valuable and perhaps could be focused more on the big ideas and fundamental understandings that such a course should provide to the students and less on specific student learning outcomes.
Big ideas are described by Wiggins & McTighe in Understanding by Design (2005) as the high-level concepts that “connect the dots for the learner by establishing learning priorities… they serve as ‘conceptual Velcro’ – they help the facts and skills stick together and stick in our minds!” (p. 66). Hansen in Idea-Based Learning (2011) describes big ideas as those concepts that characterize and are essential to the discipline and notes that two or three big ideas are typically sufficient for a course.
I propose that an introductory course in geotechnical engineering could be built around the following three big ideas:
- The practice of geotechnical engineering (i.e., the role of geotechnical engineering in a typical construction project and the process of careful synthesis of limited evidence, past experience, and engineering principles in decision making)
- Soil behavior is distinctly different from the behavior of other engineering materials
- The limitations inherent in a single course in geotechnical engineering permits only partial exploration of the engineering performance of soil and rock materials
Once the big ideas are identified, Hansen recommends that the next step is to describe the enduring understandings. In defining the term, Hansen states that enduring understandings “have withstood the test of time… and they are what the students should take away from their studies long after a given course has ended.” (p. 37) In geotechnical engineering the term “enduring” may be optimistic since the field is still relatively young and continues to develop. I propose the term “fundamental understandings” is better suited to this exercise.
The fundamental understandings associated with each of the big ideas listed above might be the following:
- The practice of geotechnical engineering:
- The geotechnical engineer has an important and specific role in the design and construction of a project.
- The interface of the built environment and the natural environment is unique to each site and project.
- The inherent variability of soil and rock creates uncertainty that can be addressed through skilled application of reliability analyses and risk management.
- The geotechnical engineer must communicate clearly in order to practice ethically and to limit liability.
- Soil behavior is distinctly different from the behavior of other engineering materials:
- A separate vocabulary is needed to describe soils and their behavior.
- Water, its presence or absence, has a significant effect on the behavior of soils.
- The settlement of soils is a complex function of multiple dependent and independent factors.
- The strength of soils is a complex function of multiple dependent and independent factors.
- The limitations inherent in a single course in geotechnical engineering permits only partial exploration of the engineering performance of soil and rock materials:
- Coursework in geology provides a geotechnical engineer with understandings of geological processes that provide the context for subsurface conditions at a site.
- Coursework in rock mechanics is necessary to understand the properties of rock formations and design methods for interfaces between bedrock and built structures.
- An introductory course provides limited practice in the application of the topics covered to engineering design. Further coursework in foundations, slope stability, retaining wall design etc., is necessary to practice geotechnical engineering.
I believe it may be possible to come to general agreement on the big ideas and fundamental understandings that should be the foundation of an introductory course in geotechnical engineering and I look forward to continued discussion on this topic. If we can articulate the big ideas and fundamental understandings, all of us who teach these classes can benefit by using this framework to design courses that address these topics while also being in alignment with our particular institutional type, mission, and students.