Teaching an introductory course in soil mechanics using problem based learning

Engineering a natural material to produce a structure with form and function can prove challenging for an undergraduate student. First encounters with soil as an engineering material can undermine a student’s confidence in their analytical thinking. Moreover, predicting the behaviour and strength of soil with the same degree of certainty as other common engineering materials i.e. those which obey the well established theories of elasticity and plasticity is at the core of this unease. Unfortunately the mechanics of soil behaviour requires a broadening of the conceptual ‘model’ for interpreting or predicting its response when loaded. The struggle to move from continuum mechanics in the case of steel for example, to a particulate material in the case of soil disturbs the students fragile understanding already gained from such compliant materials. The challenge is often exacerbated by the lack of a unifying context within which the knowledge can be applied and tested. In this paper we reflect on numerous iterations conducted over a seven year period delivering an introductory course in soil mechanics. The course is taken by the civil engineering (CE) and construction management and engineering (CME) programmes at the University of Limerick. The paper explains how the initial offering has changed to produce a carefully considered problem or trigger for learning so the intended engineering tenets are mastered. This is accomplished using a collaborative pedagogy which places small student teams at the heart of the learning process. Analysis of student results over a five year period and feedback from the 2014 cohort gathered anonymously using audience response units (clickers) are presented. These are discussed in light of instructional changes made by the lecturer that have resulted in a significant upward trend in overall performance over the past two years. In the most recent instructional intervention, use of flipped learning resources and re-sequencing of core material delivery to be more in line with the demands of the Problem Based Learning (PBL) trigger appear to have contributed positively to this year’s improvement.