Malcom Joab, BSc., MSc, DIC, MAPETT, R.Eng

A Chat with Engineer Malcom Joab, an accomplished Geotechnical Engineer

Engineer Malcom Joab has had a rewarding and accomplished Career in Geotechnical Engineering spanning a period of 30 plus years. Malcom is a Registered specialist Geotechnical Engineer with the Board of Engineering of Trinidad and Tobago, a Member of the Association of Professional Engineers of Trinidad and Tobago and currently serves as a member of the D19 – Soil and Rock Committee of the American Society for Testing & Materials (ASTM) which assesses and votes on updates to current and new ASTM specifications for testing methods on soil and rock. The latter, in particular, allows him to stay up to date on testing methods and reporting on soil and rock materials.

As a Director of the consultancy geotechnical engineering practice of Geotech Associates Ltd, Malcom has been at the forefront of many major Geotechnical Investigations in Trinidad and Tobago, the wider Caribbean, Central and South America. He therefore has a profound understanding of the vital role of geotechnical engineering in civil engineering projects and is expertly competent to caution that you neglect the recommendations of a geotechnical investigation report at your peril.

Q1. Congratulations on achieving your specialist registration status with the Board of Engineering in Geotechnical Engineering, having been previously registered as a Civil Engineer! You have been practicing in this specialist field for quite some time, can you tell us about your journey in specializing in Geotechnical Engineering?

Thank you very much. My journey over the last 30 plus years has been very rewarding both personally and professionally. I have had the opportunity to practice in many very different geotechnical environments in almost each of the English-speaking territories of the Caribbean, Central and South America, and it has truly been a tremendous experience … thus far!

Q2. How do you perceive the role of geotechnical engineering in civil engineering projects, and what motivated you to pursue this specialization?

I see the role of geotechnical engineering in civil engineering projects as a vital one. You neglect the recommendations of a geotechnical investigation report at your peril. I recall a professor of geotechnical engineering once saying, “If you don’t pay for a geotechnical investigation before the construction project, you’ll pay for it dearly during and after its completion.”

My first motivation to pursue this specialization came as a second-year student at UWI, when I first studied Soil Mechanics. Like many, I thought that civil engineering was synonymous with structural engineering, until I realized that everything you build rests ultimately on the ground – that’s where the geotechnical engineer comes in. I subsequently went on to study advanced Foundation Engineering in final year, writing my own computer program in FORTRAN to solve a 2D consolidation problem using the finite difference technique. Then, I read for MSc and DIC degrees at Imperial College, London, under luminaries such as Professors Sir A.W. Skempton, J.B. Burland, R. Chandler, P. Vaughn, and D.M. Potts, to name a few. These engineers revolutionized geotechnics over the course of decades all over the world, and they were an incredible inspiration. I was hooked!

Q3. Geotechnical engineering deals with the behavior of earth materials, like soil and rock, and their interaction with structures. Can you share any specific project experience where your geotechnical expertise significantly influenced the project’s outcome?

When I was a student at Imperial College, two of my lecturers: Professors Burland and Potts, worked on correcting the excessive lean of the Leaning Tower of Pisa, using inter alia the finite element method and advanced computer soil models. The finite element technique has always been a passion of mine, and, over the last decade, I have used this technique often in geotechnical engineering on projects both locally and regionally.

One of our clients was involved with the construction of an earth embankment which varied in height from about 2 – 8 m, and their client had very stringent settlement limitations. Initially an expensive solution was proposed by others, and our client was interested in saving time and cost. To complicate matters further, there was also a concern regarding slope instability, the rate of construction of the embankment, and at one end, there was a very complicated geometric form which rendered conventional/plane strain analysis inapplicable.

Based on my review of the available geotechnical data and a supplemental borehole advanced by ourselves, I calibrated advanced soil models, constructed a 3D analytical embankment, checked for embankment stability, both under static and earthquake conditions, and predicted the amount and rate of settlement using an advanced finite element modelling technique. Furthermore, I was engaged to monitor both the consolidation settlement and soil pore water pressures. When a comparison was made between the actual and predicted settlement amount and rate, they were essentially identical. This led to a significant cost and time savings to the project over the original option.

Q4. What are some common challenges you’ve encountered in geotechnical engineering projects, and how have you overcome them?

I would categorize the common challenges as twofold: dated ways of thinking, and the everybody-is-an-expert scenario. Firstly, some engineers may have been exposed to some aspect of soil mechanics/geotechnics during their formative years at university. However, the practice of geotechnical engineering has developed significantly, particularly within the last 20 – 25 years or so. So, when I propose a new technique or computational methodology, it can be met with skepticism and resistance. Secondly, the everybody-is-an-expert scenario is much more widespread (i.e., not only confined to engineers). Even if someone has never heard of the field of geotechnical engineering, they nonetheless have all the answers.

How have I overcome these challenges? My first response is to listen intently. Although their responses may be dated or generally inaccurate, there can be, most times, some nugget of information which can prove helpful in the geotechnical study. My second response is to inform. I endeavor to create a rapport so they may understand either the recent advances in the field or specifics about the geotechnical project/problem itself.

Q5. Geotechnical investigations play a crucial role in project planning and design. Could you discuss your approach to conducting thorough geotechnical investigations, including the methods and techniques you utilize?

The first order of business in approaching a thorough geotechnical investigation is to have a verygood understanding of what the Client is proposing to construct or, as in the case of forensic studies, a very good understanding of the nature of the problem. In other words – begin with the end in mind. Next in the process is designing an adequate geotechnical study. To aid in this regard, I review previous geotechnical and geological studies conducted in a similar geotechnical/geological regime to gain an understanding of the nature of the deposits.

Geotechnical studies include determining the scope of the fieldwork, which includes the number and depths of the boreholes, test-pits and/or scope of geophysical measurements; the number and type of laboratory tests; and types of geotechnical analyses. The primary aim of the field and laboratory work is to provide sufficient input parameters for the geotechnical analyses … the end result.

Q6. How do you stay updated with the latest advancements and technologies in geotechnical engineering, and how do you incorporate them into your practice?

At Imperial College I was exposed to their process of inquisitiveness and innovation. I left with the intention to apply this process to my practice locally. Fortunately, the senior professionals at Geotech Associates Ltd.  at the time supported this. Staying updated has taken various forms. Firstly, at Geotech we have a wide variety of reference books and academic journals on a wide variety of geotechnical sub-specializations. Additionally, the company has also sponsored my attendance at many conferences, symposia and short courses at universities and research/manufacturing companies in the United States and United Kingdom.

These training courses have resulted in the company widening its portfolio to provide additional services such as pile dynamic analyses, construction vibration monitoring and analyses, 3D finite element analysis, and the geophysical techniques, viz. 2D multichannel analysis of surface waves (MASW) and electrical resistivity tomography (ERT).

These additional services have revolutionized geotechnical practice, and it means that we can provide greater geotechnical data from which we can provide more detailed geotechnical information and analyze the subsurface accordingly.

Currently I serve as a member of the D19 – Soil and Rock Committee of the American Society for Testing & Materials (ASTM). In my view, ASTM specifications are the most widely used testing specifications locally, and being a part of this committee, which assesses and votes on updates to current and new ASTM specifications for testing methods on soil and rock ensures that I stay up to date on testing methods and reporting.

Q7. Collaboration is often essential in engineering projects. How do you effectively collaborate with other professionals, such as structural engineers and architects, to ensure that geotechnical considerations are integrated into the overall project design?

I agree that collaboration is very important in many, if not all, engineering projects. I think that communication is vital in the process of collaboration. Effective communication itself is multifaceted. On several projects, not only am I striving to communicate clearly in our geotechnical reports, emails, and letters of correspondence, I have found that being able to make effective presentations has become increasingly important, particularly in a post-COVID world in which video conferencing is increasingly used.

I recall being on a project in which the Client requested weekly meetings to keep all abreast of geotechnical matters and I found that preparing and delivering weekly presentations effectively went a long way in addressing the concerns of the Client, facilitating any questions, and giving the technical reasons why certain geotechnical decisions had to be made.

Q8. Can you share any experience where you had to make critical decisions based on geotechnical data and analysis? How did you ensure the accuracy and reliability of your decisions?

In answering this question, I would refer to the project I just mentioned. In that project, my review of the previous geotechnical data together with my own, in conjunction with the geotechnical analyses showed that a conventional manner of approaching this problem was, in this case, not required. This was a critical shift. To improve the accuracy and reliability of that decision, field monitoring was used and continuously compared with the theoretical analyses. This is an important aspect of geotechnical engineering. Because geotechnics deals with a natural material which is often nonhomogeneous and exhibits non-linear and hysteretic behavior, field monitoring is a vital component to ensure that the analytical predictions are valid.

Q9. Geotechnical engineering involves risk assessment and mitigation strategies. Can you discuss your approach to identifying potential risks in a project and developing mitigation measures to address them?

As I mentioned earlier, having a clear understanding of the proposed development and/or site history (in the case of a forensic study) is very important. Secondly, having a good understanding of the geology and geomorphology of the area is also important. Thirdly, I rely on my experience and/or those of colleagues who would have conducted geotechnical studies in the area. Finally, there are published guidelines in respect of designing a geotechnical investigation. With these in my “geotechnical toolbox” I am equipped to reduce risk on a project.

Q10. As a specialist in geotechnical engineering, what advice would you give to junior engineers who are interested in pursuing a similar career path? What skills and knowledge do you consider essential for success in this field? Geotechnical engineering is a very rewarding field. It can be extremely taxing at times, but nonetheless when a project is completed there are a few things which can top your feeling of pride and accomplishment at a job well done. Modern geotechnical engineering is now a very multifaceted practice. I would suggest that the skills and knowledge necessary would be a strong mathematical and statistical base, strong programming, and computing skills, very good geological and applied geophysical knowledge, very good interpersonal skills, and an ability to stay abreast of a field which is changing quickly.