Most of our physical infrastructure is built on unsaturated soils, yet for both technical and historical reasons, educators continue to reserve the teaching of unsaturated soil mechanics to the graduate level curriculum. Billions of dollars are at risk annually from moisture-sensitive soil damage to infrastructure. At the other extreme, billions of dollars are wasted annually due to overly conservative structures that are designed based on an assumption of saturated soil properties. Improving student understanding of unsaturated soil behavior could result in large cost savings in both the public and private sectors. In addition, a recent survey indicates that a majority of geotechnical faculty think that unsaturated soils mechanics should be introduced at the undergraduate level. Students' depth of understanding of soils as an engineering material would be greatly enhanced via introduction of geotechnical principles for unsaturated conditions, with the saturated soil case being presented as a subset of the broader theory. This project involves developing student-centered lecture and laboratory modules on the basic principles of unsaturated soils theory and the application of these principles to problems of movement of structural foundation systems. The modules emphasize solving geo-hazard problems of collapsible and expansive soils. Emerging geotechnical challenges in the energy sector are used as additional motivational examples. These modules are being pilot-tested on students at seven universities, with a large and diverse set of students to ensure that the modules are not biased toward a particular subset of students.
Intellectual Merit: Design changes between saturated- and unsaturated-soil assumptions can be extremely significant with regard to infrastructure cost (both initial and operating), public safety, worker safety during construction, and longevity of structures. Implementation of mechanics of unsaturated soils into practice is critical for sustainable, cost-effective, and safe construction practices. Additionally, emerging geotechnical challenges, such as those associated with development of traditional and alternative energy applications, commonly require knowledge of unsaturated soil mechanics. An important step to implementation of unsaturated soil mechanics principles into practice is the introduction of this information into the undergraduate civil engineering curriculum. However, unsaturated soil mechanics principles are rarely taught in introductory geotechnical engineering courses. In this study, an interdisciplinary team of geotechnical engineers and educational technology faculty and students developed educational modules for use in undergraduate curriculum. These modules have been widely distributed, including through a well-advertised website: https://sites.google.com/a/asu.edu/unsaturated-soils-theory-in-undergraduate-civil-engineering-curriculum/. A sample slide from the module on Stress State Variables is attached as an image to this summary. The slide demonstrates the role of soil suction, a key stress state variable for unsaturated soil response, through a well-known example of sand castle construction. There are lecture modules, laboratory modules, and materials that can be used by faculty at any university, and all are available through the above-referenced web site. A part of the research was aimed at observing the learning outcomes that result from implementation of these learning materials. A pre- and post- class survey was performed to help the research group improve the learning material. Students were asked a series of 14 questions; they included demographic and attitudinal data. Six questions were based on a Likert-type from 1 Strongly Disagree, 2 Disagree, 3 Neither, 4 Agree, and 5 Strongly Agree, three were open-ended and five were demographic. All attitudinal questions were designed to elicit students’ attitudes regarding the learning material developed by the design team. Faculty at pilot-testing universities were also asked to participate in surveys and in an interview conducted using a semi-structured interview protocol. Survey questions included yes/no, Likert-type and open-ended questions. Faculty were also asked to complete open-ended questions to elicit their attitudes towards the learning materials. The instructional design team also participated in an interview using the semi-structured interview protocol. The interview protocol included Likert-type and several open-ended questions. All input was used to improve learning modules. Dick, et. al (2011) was used as a guide to completing the learning material. Different iterations of the learning material were developed as the team used feedback from the faculty and student surveys, interviews and personal discussions. The team used a nine-question survey of student understanding in basic and essential unsaturated soil concepts. Development of one of the learning modules on the state of stress in soils was completed and tested in the fall of 2012. By the fall of 2013, the team had completed and tested the entire learning unit, including a lecture on the state of stress in soils, a lecture on the soil-water characteristic curve, a pre-laboratory lecture on axis translation and laboratory exercises. The students’ scores with only one module indicated no significant gains. This indicated that, although there was a slight gain in pre-test to post-test scores, the use of only one module is not enough to garner significant gains. However, when most of or the entire learning unit was implemented in the fall of 2013 we did find a significant gain from pre-test. This result would indicate that when the students are exposed to most or the entire curriculum developed by the team, they are capable of significant growth. Broader Impacts: Billions of dollars are at risk annually from moisture-sensitive soil damage to public infrastructure, and opportunities for large cost savings arising out of improved fundamental understanding of unsaturated soil behavior are great. Through availability of the learning modules to geotechnical faculty, the introduction of unsaturated soil behavior into the undergraduate engineering curriculum is facilitated, which can lead to widespread adoption of these cost-saving methodologies in engineering practice. It is expected that the teaching of unsaturated soil mechanics at the introductory geotechnical engineering level will promote its use in engineering practice. The use of unsaturated soil mechanics in the design of engineering structures will lead to more cost-effective and sustainable public infrastructure in the future. This project included education of underrepresented STEM student participants as well as students in educational technology. The interdisciplinary nature of the research team, blending expertise in geotechnical engineering and instructional technology, supports innovative research into pedagogy for engineering education. The project emphasis on introduction of new educational materials to a change-resistant audience has general applicability to engineering curriculum change. References: Dick, W., Carey, L, & Carey, J. O. (2011). The Systematic Design of Instruction (7th ed.). Upper Saddle River, NJ: Pearson.
