Soil Engineering Reports: Why You Need Them and How They Work

Also known as soils reports and geotechnical investigations, soil engineering reports are investigations undertaken by geotechnical engineers to discover the properties of soil and earthworks at a proposed or existing building site. These geotechnical soils reports help developers understand the status of the ground where they plan to build structures, and they also help contractors understand how to repair buildings that have been damaged by natural disasters. These reports may be required by local or state regulations, so read on to learn more about soil reports and what they can tell you.


What Does a Soil Report Tell You?

There are thousands of different kinds of soil, and each soil type behaves differently. In areas that are prone to natural disasters, such as mudslides and earthquakes, some types of soil may shift or compact, which could ruin the foundation of your building and cause your structure to collapse. A soil report for your foundation or any other part of your structure will provide you with a detailed snapshot of the type of soil that exists under your proposed building site. The main purpose of a soil report is to provide you with a professional analysis on the safety of your planned structure, but a thorough soil report can also provide a bunch of other information that may be useful to developers. Soil reports vary in intensiveness. In some cases, a geotechnical professional may be able to provide you with everything you need to know about your site with a cursory walk around the property. In other instances, both surface and sub-surface soil samples may be extracted and subjected to laboratory testing. In addition, geotechnical engineers might employ geophysical tools, such as spectral analysis and surface wave reflection, to get an even more detailed grasp of the status of your soil.  

What Are the Stages of Site Investigation?

Not every soil investigation follows the same steps. However, there are a few stages that even the most detailed soil reports follow. Here are a few of the stages that you’ll probably encounter as your soil report gets underway:

1. Select a Geotechnical Engineer

First, you’ll need to select the right geotechnical engineering firm for your purposes. As you select the perfect company, make your choice based on each firm’s reputation, experience in the industry, and level of certification.

2. Soil Investigation

Some soil investigations may be limited to obtaining surface soil samples or simply walking around the property and gauging the properties of soil visually. While your soil investigation could take less than an hour to complete, it’s also possible that your geotechnical engineers might end up performing complex geophysical tests.

3. Acquisition of Soil Samples

For most soil reports, geotechnical engineers acquire samples of the soil at the surface of your property and the soil beneath the surface. Depending on the circumstances, either disturbed or undisturbed samples may be acquired. Disturbed samples contain soil that has been mixed or moved around in a way that changes its composition, but undisturbed samples have been jostled and rearranged as little as possible.

4. Lab Testing

Once the soil samples have been acquired from your site, your geotechnical engineering firm will transport these samples for testing. A variety of parameters, such as Atterberg limits and particle size, will be determined, and specialized tests, such as R-Value tests and direct shear tests, will also be performed to get even more data. These tests will give your geotechnical engineering firm an in-depth look at the makeup of your site’s soil and how it will perform under pressure.

5. Thorough Reporting

Whether you’re getting a soil report for construction or the repair of an existing structure, your geotechnical engineer will provide a detailed report back for your consideration. Your finished report will contain a wide variety of different data points, but when combined, these disparate pieces of data will paint a comprehensive picture of how safe your soil is and which measures will need to be taken to ensure the structural integrity of your building.  

How Much Does a Soil Investigation Cost?

The price of a soil engineering report depends on the type of report you choose. Non-intensive types of soil investigation, such as modified soils reports, are the least expensive, but the price of your soil report rises as more specialized techniques are employed. Additionally, every building site is different, and your geotechnical engineer will need to take any unique property quirks into consideration as they perform your soil investigation. Here at AES, we offer a full suite of soil investigation services that will provide you with a comprehensive look at the safety of the soil underneath your property. From environmental site assessments to advanced geophysical techniques, our services provide you with everything you need to know about the viability of your new building site and what it will take to recover from natural disasters. To get started with an estimate, give us a call at 818-552-6000 today!
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