Practice-Centric Geotechnical Education
PRACTICE-CENTRIC GEOTECHNICAL EDUCATION
Hasan Abdullah
Chief Research Officer, Central Soil & Materials Research Station, New Delhi–110 016, India.
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ABSTRACT: The paper, first, establishes the uniqueness of geotechnical engineering discipline. In case of significant geotechnical engineering works, such as large dams and long tunnels, the primary source of uniqueness is the ‘non-conformist’ nature of the huge mass of earth, because it is formed in the vast and varied laboratory of Nature, over the mind-boggling, geological time scale. The uniqueness of the discipline demands that special attention is paid towards the relationship between theory, education, professional practice and research in geotechnical engineering, and, the hybrid approach, comprising scientific idealisation(s) and empirical criteria, is adopted in order to find optimal and safe solutions for geotechnical engineering questions. In fact, every major geotechnical engineering work needs to be treated as a research project, and solved ingeniously, thereby advancing the discipline in the process. The paper concludes with a plea for an attitudinal change towards geotechnical engineering education and profession.
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Practice-Centric Geotechnical Education
1. INTRODUCTION
The general purpose of education is to lessen our ignorance. And, with the advancement of knowledge, its compartmentalisation became inevitable—for the tiny human mind of even the greatest intellectual colossus could not contain all knowledge even pertaining to a given specialisation. However, it is necessary that we do not lose sight of the interconnections between different facets of knowledge, before delving deep into a specific domain.
The school level education provides the broad base and readies the student for reception of specialised education. And, I am of the convinced view that irrespective of the specialised stream of knowledge that one pursues at the undergraduate and graduate levels, one needs to pursue science stream at the school level, as that helps the development of one’s cognitive abilities best.
The undergraduate and graduate level education is primarily meant to equip one for meeting the challenges of professional practice. And, therefore, especially in case of geotechnical engineering practice, where, more often than not, in a given situation, different theories cannot be applied in a copy-book style, and every major project is pregnant with the possibility of uniqueness and surprises, education needs to be practice-centric, and, the professional practice research-oriented. The naturally occurring earthen material—i.e., soil or rock, formed as a result of natural processes spread over geological time scale—is highly varied over space. And, in geotechnical engineering, the theories have serious limitations.
The foregoing prods one to first appreciate the uniqueness of the discipline of geotechnical engineering, and then critically examine the existing relationship between education and professional practice in this special area. Finally, the exercise leads to some loud thinking with regard to relationship between education and profession in the field of geotechnical engineering.
2. Uniqueness of geotechnical engineering
The vagaries of Nature spread over geological time-scale, produce high variability with regard to the properties and responses of a geotechnical material—soil, and particularly rock. For large dams or long tunnels, not only high variability of the influenced strata is the norm, but even singularities, termed geological surprises, are common. To do engineering, one assumes the rock to be “continuous, homogeneous, isotropic, and linearly elastic” (acronym CHILE), whereas, in reality, and invariably, the rock-mass is discontinuous, inhomogeneous, anisotropic, and non-elastic (acronym DIANE). Moreover, the rock refuses to slavishly conform to our principles and theories.
Given the practicability aspect, i.e., keeping the constraints of knowledge, technology, economics and time in view, surprises with regard to the anticipated properties and parameters of the rock-mass, over the zone of influence of the proposed structure, can hardly be avoided. The geophysical methods, employed to ‘scan and predict’ the properties of rock-mass spread over vast volume, are indirect, and have limitations; and, cannot ensure elimination of the possibility of a geological surprise.
Drilling, resorted to get the direct information on the substratum, brings in clarity, and helps in the interpretation of the geophysical data. Drilling gives line-wise information, whereas the geophysical methods cover a vast area but give inferred information. And, therefore, these two methods are used in conjunction so as to obtain optimum information employing minimal resources.
The rock-mass has several peculiarities, which cannot be captured in the laboratory sample. And, often, these features of rock-mass—for instance, folds and faults—are very crucial, and govern the response of the rock-mass in real life situations. Also, to be noted is that in the laboratory, the rock sample is divorced from the in situ environment, i.e., the in situ stress is absent in the laboratory. The macro-level features and variability of rock-mass, and the difference of several orders of scale between laboratory sample and the in situ mass, put a big question mark over the applicability of the laboratory assessment of rock to its in situ behaviour. However, as assessment of rock in-situ is a very expensive proposition—in terms of time and money, both—great reliance on the laboratory evaluation of rock is practically inevitable.
The methodology employed to understand rock involves ‘mechanical addition’ of responses—as if these take place in isolation, and one-after-the-other; whereas, in real life, different phenomena act simultaneously. And, it is quite obvious that in general, the two- simultaneous actions and those very actions but ‘one-by-one’ would not yield identical results.
The foregoing aspects provide uniqueness to the profession of geotechnical engineering, and these necessitate that the subject of geotechnical engineering—in terms of (concrete materialist) practice—is given a special treatment. The history of the development of geotechnical engineering, however, has shown that the practice, in a way, precedes the discovery of principles, and generalizations have serious limitations while dealing with the naturally occurring rock-mass. The uniqueness of rock in some detail has been discussed by Abdullah et al. (2004).
In certain situations, the scientific idealisations lead to absurd answers, and to make the assumptions that are appropriate for a given problem is a very crucial first step in solving a geotechnical question. On the other hand, an empiricism-based formulation not only lacks the perfectly scientific underpinnings, but is also based only on the evidence available with the one who has advanced the theory; whereas, more often than not, a crucial aspect—the uniqueness of Nature that seldom replicates herself—makes most geotechnical questions site-specific.
The foregoing demands that ingenuity needs to be the watchword, while dealing with geotechnical engineering problems of significance; and, it also underlines the importance of research. And, the viewpoint that accords primacy to solution of practical problems—even in education —has a case, which deserves our serious consideration.
3. Geotechnical engineering education
At the top end, the pursuance of doctoral degree is the intensive exploration of an uncharted course in a very narrow domain. However, the geotechnical engineering is introduced at the undergraduate level; and, to squeeze in more knowledge may not be feasible. But, the importance of properly designed graduate curriculum cannot be over-emphasised as there seems to be quite some gulf between the courses of study and the professional practice, and it is here that the real all-rounder geotechnical engineering professional of tomorrow is groomed.
3.1 Graduate-level Curriculum
In order to optimally prepare the geotechnical engineering professional with holistic understanding of the subject, the two components of the curriculum, namely theory and practical, both, need to be re-designed, and adequately supplemented by the real-life problems.
The apportioning of time between theory and practical needs to be looked into, and what all should be covered under theory, and what shall be the approach and orientation of teaching also need consideration. The philosophy behind the course design should provide a good and comprehensive introduction of the discipline, and include the justification for the course and its design.
The foundation course shall be made the all-important pivot, around which the whole curriculum develops. Also, each topic must be introduced enunciating its philosophy, so as to place it in proper perspective. The holistic perspective and the context need to be given adequate importance.
In theory, the students need to be explained the basics of the discipline and the issues of fundamental import, and also taught as to “how to catch the fish”. It is not the ‘solution’ of a problem that is all-important, but the knowledge about ‘the way to attack’ a problem, and ‘why to attack’ in a particular way are hugely significant issues.
The details pertaining to ‘what’ of theory can be gone into by the students on their own; the teacher’s input needs to be with regard to the significance of different aspects, so that the students can appreciate the real import and applicability of different formulations. The teacher needs to explain as to which theory shall be applicable under what circumstances, and what factors/parameters would have crucial bearing in which case.
3.1.1 The Practical Work
Not only the practical class, where the student learns to conduct specific tests, but visits to project sites of significant geotechnical problems, in situ testing, instrumentation, assignments (dealing with back analysis of problems and failures) and all other components that help solve real life problems should be treated as the constituents of the practical work, so that the student develops the real feel for the subject, and appreciates the role of theory in practice.
The philosophy of REMIT (Rock Engineering Mechanisms Information Technology), enunciated by Hudson (1992) should also be introduced as it helps one realise that because of our inability to take simultaneous cognisance of different phenomena, the methodology of ‘fragmentation and assimilation’—where we first try to solve the problem part-by-part, and then integrate the ‘solutions’ thus obtained—is normally employed. However, it takes one away from reality, and introduces distortion/error because, actually, different phenomena act simultaneously.
In the conventional practical classes, where the laboratory investigations are conducted, more emphasis needs to be laid on the limitations and applications of the particular test rather than on conducting the test. To answer the “why, and why not” of every involved step is more crucial than memorisation of the details of testing. The students should be made to realise that every attendant circumstance has a bearing on the obtained result.
The compatibility between different parameters and properties of a given rock needs to be emphasised. In case of the wide variation in a parameter, say the Young’s Modulus values, of a given rock type from a given area, the same needs to be explained. And, this divergence may be explained by the wave velocity (compression and shear), evaluated under dry and saturated, both, states (Abdullah et. al, 1999; 2002). Similarly, different properties and parameters of rock, evaluated in the laboratory, may also help one better appreciate the value of (and the scatter in) different properties and parameters.
The teacher needs to discuss all aspects of laboratory assessment. The drilling, core recovery, drillhole log, storage of core etc., and also the number of samples tested, the inherent variability of the rock, all, would have to be taken into account, while recommending the value of any parameter for design. If the laboratory testing were accompanied with the above discussion, then that would go a long way in widening the horizon of the student (Abdullah et al. 2007). It would make the student realise that one couldn’t be oblivious of attendant circumstances, while using the value of Young’s Modulus—or for that matter any other parameter—say, in numerical modelling. The ‘why’ has to be explained for all that one does. Once the student learns to raise the right questions, to find the correct answer(s) would only be a small step from there.
Let us now take up in situ testing. It may not be feasible for the students to carry out in situ tests, because of the time involved. However, the tie-up with the organisations involved in in situ assessment can help students witness the in-situ tests, and also appreciate the pluses and minuses of in situ testing. The special lectures (in person, or audio-visual) by these specialists can also help broaden the horizon of the students. The reports of these organisations can also be studied and reviewed by the students.
One other component of Practical Work is the Assignments. The Case Studies provide a very useful way to develop holistic understanding. The students have to be made to interlink different aspects, in order to comprehensively grapple with the problem. Every student must be given a different assignment, and asked to present his/her work before the whole class, to be followed by a discussion.
Instrumentation is a very important—however, quite neglected—component of practical work. The role of instrumentation, in a major project, commences at the pre-construction stage, and continues throughout the construction phase, and is important even in post-construction (or in-service) period. It is through instrumentation alone that assumptions and theories are verified, and knowledge advanced.
Physical Modelling is also a way to understand, and advance, geotechnical engineering. However, with passing time, due to advancements in computational facilities and numerical methods, the attention towards Physical Modelling has been getting diminished. However, ultimately, every theory has to be physically ‘verified’, as a naturally occurring material is not obliged to conform to assumptions—explicitly stated, or implied. Hence, in order to make our understanding of the earth forming materials ever better, and make our theories more realistic, these need to be continually revised in the light of the actual responses’ data collected over time.
Application of Finite Element Method in Geotechnical Engineering is taught, and must be continued. The practical work must involve exposure to at least some of the commercially available software codes. However, more important is that the students are made aware as to how to evaluate these codes.
3.2 Research Work
There needs to be more interaction between those involved in research work at the institutes of higher learning and the professional practitioners. If, on one hand, the educational institutes tend to unfairly gravitate towards idealised (not to say sterile) theorisation, the practicing professionals tend to disregard theoretical insights altogether. The former perhaps prefer the certainties afforded by the theories, whereas the latter are attracted towards only that is directly applicable. However, a balance needs to be struck between the two; and, not only should the research activity be made more practice-oriented, the practice also needs to be integrated more with research activity.