Australian Engineering Geology – State Of The Art

Engineering Geology is the science devoted to the investigation, study and solution of the engineering and environmental problems which may arise as the result of the interaction between geology and the works and activities of man, as well as to the prediction and of the development of measures for prevention or remediation of geological hazards (IAEG, 2024).

Engineering geology is an essential input to geotechnical engineering for the simple fact that without geological input or an engineering geological model there is nothing to base the engineering upon. Whilst there is appreciable overlap between the skillset possessed by the geotechnical engineer and the engineering geologist, it is the engineering geologist who brings an understanding of earth processes, and geological history to the development of the ground model, and it is the engineering geologist who through their understanding of natural processes identifies and assesses geological hazards to the project.

The geology of Australia includes virtually all known rock types, spanning a geological time period of over 3.8 billion years, including some of the oldest rocks on earth. It is a complex geological setting, with complex geological processes acting which makes the need for sound engineering geological input to our projects all the more critical.

The inherent Australian landscapes provide a myriad of both typical and atypical natural geological and geomorphological characteristics, with a rich history of landform development associated with changes in facies and structural controls overprinted by a unique set of Quaternary conditions, with many areas affected by relatively recent (in geological time) volcanic activity.

The transported and/or parent rock weathered derived soils forming the uppermost strata in many places include common varieties (alluvial, colluvial, estuarine, marine, aeolian, residual) and uncommon types such as duricrusts, reactive, sodic and acid sulphate soils. These uncommon types of soils provide challenges to the design and construction of the built environment in terms of their potential for reuse, taking into consideration sustainability, as well as their actual behaviour as a result of natural or anthropogenic changes or impacts.

The importance of the Engineering Geology discipline to Australia is significant and is often misunderstood and/or under-valued, both by government, construction and mining-based industries, learned societies and Academica alike.

Engineering Geologists have, continue to and will in the future, play key roles, in the development, and often through the full life cycle, of major infrastructure projects covering the full gambit of urban or greenfield terrestrial and marine environments in this country. From the concept level in terms of review of existing information and remote sensing; through to site reconnaissance and mapping; designing, managing and interpreting associated geotechnical investigations; geological and geotechnical model development; design parameter definition and ground behaviour analysis; assessment of construction materials; earthworks, slope stability and natural terrain hazard assessment, as well as associated risk management and the derivation of mitigation measures/strategies, all fall under the sphere of the discipline.

Often engineering disciplines outside the realms of ground engineering, as well as client organisations and/or decision makers, do not have the necessary knowledge/experience to differentiate between the skill sets of Engineering Geologists and Geotechnical Engineers, and for the most part they don’t need to – as far as they are concerned, they need to get ‘geotech’ done.

If one considers ‘geotechnical practice’ or ‘geotechnics’ to encompass the range of geological and engineering skills necessary to service projects, then skills in geotechnics can be considered to cover a spectrum between geological skills, typically taught through geoscience education, and engineering skills taught through an engineering education. Most, if not all geotechnical practitioners have at least an awareness of the skills brought by their counterparts – engineering geologists have at least an awareness of geotechnical engineering and geotechnical engineers have at least an awareness of engineering geology. However, within the geotechnical profession there are practitioners who through further study or vocational training advance their skills further along the spectrum. There are practitioners with geoscience backgrounds competent to perform what might traditionally be considered engineering functions and vice versa, engineers competent to perform what might traditionally be considered geological functions. This is a wonderful characteristic of the geotechnical profession. It brings together people with backgrounds in science and engineering, their skills are combined to provide ‘geotechnics’ and there are opportunities to develop new skills throughout a career in the field.

Simplistically and traditionally, Australian educated Geotechnical Engineers are more likely to have followed a hybrid path studying both civil/structural engineering aspects coupled with specific units or modules in geotechnical engineering such as earthworks, foundation design and earth-retaining structures. They may be more focussed on soil mechanics and the associated behaviour of pedological strata (soils) and may typically lack knowledge of the fundamentals of geology such as the theory of super-position and structural geology. In this way the role of Engineering Geologists generally lies in the methods required to “read the landscape”, define associated ground models, understand how the ground might respond to change caused by a project and how the ground might impact on a project and to offer solutions to manage the ground response. The engineering geologist can also bring knowledge of rock and its weathering profile and engineering behaviour that is generally lacking from Australian engineering education.

Often Engineering Geologists are the first to site with critical inputs into the actual early decision-making process and the development of projects in terms of their locality, form and the approval of funding for later design phases, as well as if projects are ultimately built or not. Their influence on the cost and direction of projects can be very significant – for example the development of a sound conceptual ground model early in a project could lead to a decision to align a tunnel through better ground or perhaps not tunnel at all which could have significant impact on subsequent design and construction costs.

The criticality of the accuracy and representativeness of baseline ground conditions derived from good landform analysis, understanding of geological history and processes, supplemented by site investigations cannot be underestimated. This information is used to inform model development, design parameter definition and associated ground behaviour assessments which has a direct bearing on the appropriateness of the associated design of works, related relevant construction methodologies, programs and costs. This means that if the factual information and its interpretation is not satisfactory this can and has led to exponential problems (including potential health and safety risk) through a project life cycle which has often resulted in costly and adversarial legal disputes not just in Australia but internationally. The added focus on the importance of Engineering Geology in this context cannot be underestimated as Australia is fast approaching, and if not has overtaken, the US in terms of proportional litigations for construction projects including and often related to claims of “unforeseen ground conditions”.

With the importance of Engineering Geology to the development of key infrastructure and therefore its impacts on the Australian community as a whole, it is disheartening that the discipline in Australia is at present only offered at tertiary educational level as modules, without the re- establishment of standalone either undergraduate or postgraduate courses being offered. The problem is further compounded by the fact that there is no professional registration scheme available in Australia that recognises the discipline in its singularity and therefore its importance, being absorbed into geotechnical engineering professional qualifications, where candidates have been deemed to follow university degrees in line with the “Washington Accord”. There are therefore a significant number of practising Engineering Geologists in Australia providing key inputs to projects that are presently marginalised in terms of the recognition of their critical skillsets to geotechnics and to various industries. The situation may become worse in the near future with seemingly a complete non-recognition of the discipline and its importance within the present Registered Professional Engineer schemes that have been enacted into legislation in certain States, which could be followed in the same vein soon by the remaining States and Territories.

In addition, the tandem effects of the lack of taught courses coupled with the lack of professional recognition and registration, and therefore a clear path of career development, may mean that the actual discipline could be considered as on the “endangered” list and liable to extinction in the future much like the dinosaurs that are often encountered around Winton in Central Queensland. A significant step change is therefore needed by decision makers in recognising the critical value that the discipline brings to the development of our society with the provision of the necessary education, training and professional pathways to encourage future Engineering Geologists to start and ultimately fulfill a very rewarding and significant career. The geotechnical profession is simply not complete without its geological component, and the consequences of that can only be dire.

The Australian Geomechanics Society recognises the importance of Engineering Geology to the Australian society, which has formed the basis of this themed issue that also celebrates the 60th anniversary of the foundation of the International Association for Engineering Geology and the Environment (IAEG). The papers/editorials presented in this Special Edition cover both the aforementioned problems of establishing professional pathways for Engineering Geologists in Australia, as well as showcasing the variations in geology over the Continent and the associated risks and mitigation measures and designs/approaches to deal with their inherent characteristics.

The link between the provision of appropriate education/training and registration for Australian Engineering Geologist is mutually exclusive, which has been attempted to be encapsulated in Figure 1. These issues are felt to be of such criticality to the discipline in terms of its place and development in our society, that as part of this Special Edition separate and stand-alone editorials are provided at the front of this publication, exploring in more detail these issues, before the presentation of technical papers.

In terms of registration for Engineering Geologists in Australia, existing avenues do presently exist with in-country and international learned societies. However, their registration requirements and the value they bring to practising Engineering Geologists, in terms of technical recognition and associated “formal signoff/approval” rites and associated responsibilities, within the Construction/Infrastructure industries are varied. In many cases existing practitioners either do not have the right academic qualifications and/or there is a lack of industry/governing authority recognition of the registrations being presently offered (see Figure 2).