What is Geotechnical Engineering and Do I Need a Geotechnical Investigation For My Building Project?

We often appreciate the design and construction aspects of a project, but we rarely think about all of the planning that goes into laying the groundwork to ensure the safety of the public and to help minimise the impact on the environment.

Important roles such as environmental engineers, geotechnical engineers and soil engineering are vital to informing the design process of any problems and helping to ensure the right measure are put in place to ensure the safety and success of a building process.

What Is Geotechnical Engineering?

Also known as “soil mechanics” or “rock mechanics” geotechnical engineering involves defining the soil’s strength and deformation properties. Geotechnical engineering incorporates a range of specialist fields such as soil and rock mechanics, geophysics, hydrogeology and associated disciplines such as geology.

As a branch of civil engineering, geotechnical engineering is important when it comes to the planning of infrastructures such as roads and tunnels, as well as buildings and other constructions such as mining and drilling operations both onshore and offshore. 

Geotechnical engineers provide the vitally important support that is needed in the design and construction industry, whether it’s ground and environment testing and analysis to the assessment of risk to humans and the environment.

What a ground assessment takes into account:

● Weight

● Porosity

● void-to-solid particle ratio

● Permeability

● Compressibility

● Maximum Shear Strength

● Bearing Capacity

● Deformations

A professional ground assessment is a necessary part of the ground working industry, analysing a host of soil mechanics which are vitally important to the safety of the workers and environment, and are key to the success of the project. By evaluating the risks you can put in place the steps necessary for reducing the danger to both people and the surroundings. 

Engineers also examine environmental issues such as floodplains and water tables. These assessments are important to understand if the ground area is suitable for a proposed project, and can provide an understanding of what needs to be done in terms of equipment and processes in order to make the ground safe and economically viable.

Geotechnical surveys allow engineers to evaluate the stability of the ground, including any slopes and soil deposits, assess any risks including contamination, and help to determine what type of foundations and earthworks will be required. Surveys also highlight the potential for risks such as earthquakes, landslides, seismic activity, floods and what should be put in place to mitigate the risks associated.

Geotechnical engineers are responsible for ensuring that important infrastructure such as roads, highways and railways are properly designed and maintained to ensure their longevity. This can include the measures required to protect roads from landslides, foundations for bridges and more.

All buildings, including high-rise structures, bridges, towers, antennas and essentially every major building has a foundation carefully designed by teams of geotechnical engineers to ensure it can withstand the surrounding environmental demands

Assessment of surrounding environments is crucially important, to determine the risk of landslides that threaten public safety, particularly in busy areas and major roads, geotechnical engineers provide reports on the likelihood of risks and the measures that should be taken to ensure public safety.

Geotechnical engineers are heavily involved in the design and construction of tunnels, subways and underground facilities used in tunnels, as well as underground and overground transport links and railways, waterways and waste storage. Often geotechnical engineers will be present throughout the construction process to support the development as it progresses and faces new challenges.

Large scale geotechnical engineering projects include the assessment of everything from the bed of lakes and rivers, the examination of shorelines and the wider knock-on effects to the surrounding ecosystem that a dam will have. 

Rubbish sites must be carefully planned to ensure that solid waste is isolated from the environment to protect public health. Landfills contain industrial, agricultural and household waste. This waste may contain many harmful chemicals, pesticides and biological compounds. Specially designed systems are required for separating these elements, preventing harm to the public and the environment by ensuring they are separated and disposed of responsibly.

Geotechnical engineers are vital in ensuring the stability of deep excavations. Shoring operations allow deep excavation to take place in urban areas which are vital for the construction of underground railways, roads, drainage and more in heavily built-up areas. 

Mining and drilling excavations deep below ground are incredibly risky operations which pose a significant danger to both the health of employees as well as the surrounding environment, so a thorough assessment is necessary to minimise danger.

Principles of physics and chemistry are used to modify the characteristics and properties of the subsurface so that it can support civil infrastructure that would otherwise not be possible. For example, the importing of soil and material to improve the stability and safety of the ground surface is just one example. 

Natural processes such as longshore drift and extreme weather can erode the natural landscape. Heavy rainfall, snowfall, tornadoes, hurricanes and floods can quickly change the landscape, therefore, in some cases, it is necessary to mitigate against this damage if construction work is due to take place or it poses a danger to life.

If a site has been contaminated with harmful chemicals, posing a threat to health and the environment, geotechnical engineers are often called in to assess the situation and determine the best course of action. Geoenvironmental engineers use numerous techniques to remove contaminated soil. Soil stabilisation and chemical oxidation are examples of processes employed to convert contaminated soils into non-hazardous soils to make the ground suitable for engineering projects.

Any proposed change in the structure or shape of the ground needs to be geotechnically assessed. When proposing a project you may not be aware of the environmental considerations, restraints and necessary measures that need to be handled in order for the project to be both legally and physically possible. Realising there are environmental issues with your project once it is underway can be costly, causing unforeseen delays and disasters during the building process that could have been avoided with professional help.

A key part of any site assessment involves understanding the engineering proposed for the site. Whether it’s housing, industry, a pipeline, roads or any other civil engineering work, the suitability should be assessed as early as possible in the project timeline. Choose a geotechnical engineer that endeavours to understand your project and how it interacts with the surrounding environment that is prepared to work around your project schedule. Larger projects often require ongoing geotechnical monitoring alongside the construction or engineering work.

Cheap site investigation can actually be a false economy. According to The New Civil Engineer: “Often the cheaper the site investigation, the more risk there is.” Poor site investigation can mean a lot of things. It may be a result of poorly designed surveys, under-sampling or lack of flexibility to respond to business needs on-site. It could also be down to poor acquisition or analysis resulting in unreliable results, or results that are delivered too late to influence the design process. If you compromise on quality in favour of a lower upfront price you run the risk of overlooking many important aspects of the project. Whether it’s in the form of a disaster or simply delays to the building process, these are costly aspects which should not be overlooked. In more serious cases, environmental considerations that are overlooked can result in reduced longevity of a finished project being compromised or the final project not being able to perform its function properly.

Whether it’s for agriculture, commercial or a domestic engineering project, we can provide the geotechnical engineering solutions to meet the needs of your project. From site investigation, foundation design, contaminated land development, mining risk assessments, gas monitoring, retaining wall design and much more. Get in touch with us today if you would like to learn more.