The Role of Geotechnical Engineers in Land Damage Assessments

Land damage assessments help us to gain a deep and granular understanding of the damage caused to a specific patch of earth - information that can inform the management of that land moving forward. And a geotechnical engineer plays a key role in this assessment process.

What is that role exactly? In this guide we'll dig a little deeper into the role of a geotechnical engineer, including the what's, whys and how's of assessing land damage.

Why is a land damage assessment important in the first place? Put simply, in order to mitigate or fix an issue, you first have to understand that issue.

A land damage assessment is a comprehensive evaluation process that aims to understand the nature and cause of land damage. Based on the findings, engineers will have the information they need to plan remediation or mitigation efforts that guard against the same damage happening again.

While the properties and the structural integrity of the soil will be different from site to site, the insights drawn from one land damage assessment can often be applied elsewhere.

The importance of land damage assessments is only increasing as our world warms and extreme weather events become more common. Certain areas are beginning to experience natural hazards that they haven't seen in living memory, so it's critical to understand how the land behaves under these foreign conditions.

This is why insurance companies are so eager to assess and understand land damage, as it will inform their risk analysis as we begin to sail into uncharted waters.

Land damage can come in a wealth of different forms, caused by a wealth of different events and forces:

• A geophysical event like an earthquake or volcano
• An extreme weather event like a cyclone or flood
• Gradual natural processes like coastal or wind erosion
• Landslides and slope failures
• Sinkholes and ground subsidence
• Human activities like mining damage and industrial spills that work their way into the soil and groundwater
• Construction project issues like building foundation cracks or subsidence

Land damage assessments are utilised in a number of situations, including:

Disaster recovery: Assessing damage after natural disasters like earthquakes, floods and landslides, as we did with our Horseshoe Lake regeneration project after the Canterbury earthquakes.

Construction: Evaluating the stability of land before and after construction projects.

Environmental management: Monitoring and mitigating the impact of human activities on land, like our work on the Tunnel Beach hiking trail.

Agriculture: Assessing soil health and damage to optimise farming productivity.

No matter the setting, the root cause, or the damage inflicted, a geotechnical engineer will be the driving force behind a land damage assessment. They are tasked with analysing and evaluating the physical properties of the soil and rock to understand how these factors influence the stability and usability of the land.

They will also determine how future damage can be planned for and mitigated, in an attempt to ensure the same issues don't arise again.

What does a land damage assessment look like? While each appraisal will be inherently unique, at a basic level all assessments will feature the following steps:

1. Site investigation

Geotechnical engineers will begin by conducting geotechnical surveys to gather data on soil composition, rock formations, groundwater levels and range of other geological factors. This involves techniques like drilling, sampling and in-situ testing to assess how the damage has affected the site's geological and hydrological characteristics.

2. Geotechnical analysis

The geotechnical engineers evaluate the stability of slopes, embankments and foundations. They analyse the soil samples in laboratories to understand the physical and mechanical properties - soil density, shear strength, compressibility and more - and gain an understanding of how the ground will behave under different conditions.

3. Risk assessment

The assessors analyse the data for insights. They use computer modelling and simulations to identify the risk of landslides, subsidence and ground movement, and how the land will respond to natural forces like water infiltration and seismic activity.

4. Risk mitigation

Based on the risk assessment, the geotechnical engineer will design mitigation measures that prevent or minimise land damage. These might include drainage systems, retaining walls, ground reinforcement techniques, soil stabilisation methods, or advising a specific approach to construction or farming.

Why hire a geotechnical engineer to assess land damage? First and foremost, you can't conduct a land damage assessment without one. But investing in these niche experts can also offer the following benefits:

1. A better understanding of your site: As experts in soil and rock mechanics, geotechnical engineers will provide you with a detailed analysis of the properties of your site, which allow you to maximise your use of that land.
2. Identifying risks: A geotechnical engineer will also give you a complete view of potential hazards, and prepare for the most likely risks, whether landslides, soil liquefaction, subsidence or groundwater issues.
3. Effective remediation plans: The engineer can design solutions to guard against these risks, to stabilise and reinforce the land, to improve drainage and water movement, and to ensure long-term stability.
4. Informed decision-making: Geotechnical engineers ensure you're armed with all the information you need. Detailed reports and recommendations help property owners, developers and authorities to make better decisions about how to use and develop land.
5. Ensuring compliance: Geotechnical engineers will know all the boxes you need to tick. They will ensure both the assessments and the remediation plans meet all the relevant legal and regulatory standards, to ensure you don't get blindsided by an obscure rule or forgotten form.
6. Save money: The most compelling reason to hire a geotechnical engineer? By identifying issues and providing effective solutions, they can save you significant time and money by avoiding future damage. A relatively small investment now can translate to millions of dollars in savings down the line.

Land damage assessments are critical for gaining a deeper understanding of your site, and how different factors have changed its composition. At Eliot Sinclair our expert geotechnical engineers use advanced technology and techniques to gain a deep understanding of your land, and how best to mitigate future risks, to help you maximise the use of that land both now and into the future.

Get in touch today to find out how we can help you.