Abstract:

Classical teaching of rock mechanics, with lectures using photographs, makes it difficult to put students in contact with the reality of what they are learning. Similarly, virtual environments place students in real scenarios, but prevents them from interacting comfortably and easily with reality. For this reason, the Educational Innovation in Geotechnics Group of the Universidad Politécnica de Madrid in collaboration with the Faculty of Geology of the Universidad de Oviedo have developed a methodology to facilitate student's learning of geomechanical stations through the combination of:
(i) laboratory recreations of rocky outcrops; and
(ii) a flipped classroom methodology.

As a newer aspect, 3D printings of "rock mass sections" have been used, combined with a device (or base) that allows the samples to be placed and oriented in space. Using photogrammetric techniques (in particular, the Structure from Motion photogrammetric technique), computer models of rock slopes have been recreated from photographs of real outcrops. These computer models, once edited, have been printed using a 3D printer. The printed models (or “rock mass sections”) can be placed on a base where the orientation of the sample can be fixed, recreating the real “in situ” conditions of the outcrop. In this way, the student can interact with these samples by placing the measurement devices on them to take the necessary information and to carry out the geomechanical station. Thus, for example, a compass can be placed on a discontinuity plane to know its orientation, or the Barton comb can be used to obtain a roughness profile. During the last academic year, two pilot experiences of the developed methodology have been carried out. These experiences have been done in the Civil Engineering School of the Universidad Politécnica de Madrid and in the Faculty of Geology of the Universidad de Oviedo, in subjects of two degrees that give great importance to the characterization of the ground (particularly, to the rocky mass) but with two clearly differentiated approaches (design versus characterization) that involve students with different previous training and concerns. For the student's previous work, typical of the flipped classroom methodology, a video was recorded with a real example of how a geomechanical station is made in the field.

The (in-person) laboratory practice included:
(i) a presentation by the teacher,
(ii) a time for the student to practice freely, and
(iii) an evaluable exercise in which the student made a geomechanical station.

The tests took before and after the experience showed an improvement in the understanding of geomechanical stations; moreover, the students showed a good performance in the use of the measurement devices. The surveys carried out on both students and teachers have reflected a positive opinion of the methodology, although some of its limitations have been highlighted, since it is not possible to incorporate the measurement of all the parameters of the geomechanical stations into the laboratory practice. One of the advantages of the proposed methodology is that enable to have a database of outcrops with different characteristics (which can be reprinted in the case of deterioration) and that can be oriented in different positions, thus simulating different settings and enriching student work.

Keywords:

Inverted Classroom, Geotechnics, Geomechanical Stations, 3D Printing, Rock Mechanics.