What is Geotechnical Engineering?

Aerial View of a Geotechnical engineering project

Geotechnical engineering explains the mechanics of soils and rocks and their engineering applications to the development of humankind.

The story of the engineering relationship between humans and earth, it is a branch of civil engineering that can be traced back as far as ancient times.

Today, geotechnical engineering is a crucial component in modern building practices, especially where the design and construction of major civil engineering and construction projects are concerned.

In this guide, we look at the history of geotechnical engineering, its practical applications and importance.

A Brief History of Geotechnical Engineering

Modern geotechnical engineering came to prominence between 1700 and 1900, when scientists such as Coulomb, Darcy and Atterberg published key theories on soil mechanics and the movement of water through soil.

Building on these theories, the landmark publication ‘Theoretical Soil Mechanics’, written by legendary civil engineer Karl Terzaghi in 1925, set the course for modern geotechnics.

Terzaghi, along with colleagues in 20 different countries, went on to establish the International Society for Soil Mechanics & Geotechnical Engineering (ISSMGE) In 1936.

Made up of 19,000 members across 89 countries, the ISSMGE is the leading professional body representing the interests and activities of geotechnical engineers the World over (source: ISSMGE).

Geotechnical Engineering Explained

The job of geotechnical engineers is to create a more sustainable World by investigating, designing and building through the soil and rocks that our World is built upon.

Geotechnical engineering examines the strength and deformation properties of soil, as-well as other important materials such as clay, silt, sand and rock.

A major branch of civil engineering, it is comprised of a number of specialist fields.  These are:

• Soil and rock mechanics – describes the behaviour of soils, providing the theoretical basis for analysis in geotechnical engineering;

• Geophysics – uses maths and physics to analyse the Earth’s internal structure and dynamics;

• Hydrogeology – examines the movement, behaviour and quality of water found underground (i.e. in the soil and rocks of the Earth’s crust);

• Engineering geology – combining the fields of Earth sciences and engineering, engineering geology examines the likely impact major construction developments will have on the land they are built on.

Where major building developments are concerned, geotechnical engineering is required to determine ground strength prior to construction.

Furthermore, it is crucial in the design and analysis of a range of structures that are supported by soil or rock, including building foundations, embankments, roads, tunnels, levees and landfills.

Typical Duties of Geotechnical Engineers

Geotechnical engineers spend most of their time in the field and conducting analyses in geotechnical laboratories.

A varied and challenging role, no two days are the same – the range of activities a geotechnical engineer will tackle on a daily basis depends very much on the number and scope of projects at hand.

A multi-disciplined profession, typical duties include:

• Subsurface investigation: Collection of soil samples to determine stress bearing capability and the stability of the ground

• Field testing: Once the subsurface investigation has been carried out, further testing is required to determine if the quality of the land in use will present any safety risks

• Computer analysis: Using specialist software, the findings of any subsurface investigation and field testing are analysed, the results of which will usually contribute to the development of earthworks and the construction of foundations.

Geotechnical engineers will also be required to attend regular client meetings to provide project status reports and discuss budget and time constraints.

The Importance of Geotechnical Engineering

‘Everything you see around you is supported by soil and rock; anything that is not supported by soil or rock either floats, flies or falls down’ (source: whatisgeotech.org).

History teaches us many valuable lessons.  In the past, a lack of geotechnical awareness has been the catalyst for a series of disasters and near misses.

Take for instance Paris in the 1700s, which started to collapse due to underground limescale quarries used to create the icon buildings it is famous for.

Amidst a growing population and an increased need for buildings and appropriate infrastructure, human safety is paramount.  The analysis of rock and soil mechanics can help to vastly improve building and infrastructure integrity, preventing collapse and, worst still, catastrophe.

Climate change is also an issue.  One of the defining issues of our time, the threat of climate change, alongside the frequency and severity of natural disasters, demands stronger infrastructure.  The collapse of the water defence system of New Orleans in 2003, as a result of the hurricane Katrina, is testament to this.