Understanding a Soil Report

Association of Construction and Development
October 23, 2012 — 3,899 views  

Understanding a Soil Report

The soil beneath a structure can provide critical information about the viability of a particular building project. Geotechnical soil reports, also known as soil surveys, analyze the various types of soils in a particular area to reveal their unique properties and conditions. Some kinds of soils are better suited for construction than others. They can displace weight loads much more evenly without risking harm to the structure because of shifting. Soil reports are critical pieces of information to engineers, builders and inspectors. Understanding their contents can make or break a project.

A soil report first describes the proposed building project, outlines its scope and identifies its location. To analyze the soil, the geotechnical engineer takes soil samples and processes them. The report will then list the methods use to extract the samples and the techniques used to analyze them. Next, conditions of the project site are discussed. Here is a typical list of such conditions:

- Landslides
- Terrain
- Geology
- Seismic characteristics
- Any prior land usage
- Water table
- Faults located near the project
- Miscellaneous items like sink holes

From this list, the report will move on to making specific recommendations about the project. These recommendations touch on such subjects as dewatering, load requirements and possible settlement issues. Next, the report will have maps detailing all of the above information in visual form. The maps are usually listed in order of the data points. Locations where samples were taken will be marked on the maps along with the locations of fault lines and geological features.

The sample logs describe the characteristics of the samples that were taken earlier. Each sample consists of a long plastic tube that clearly shows the transition between different soil levels. The types of soil displayed in the sample have specific densities, moisture levels and attributes, all of which will be included in this section of the report. 

Along with the sample elements, test results are also written up. These tests determine such as things as contamination, direct shear stress and the size of individual soil particles. Details about the soil particles themselves, like their granularity, may also be included.

The soil report contains many pieces of valuable information. Structural or design engineers can use the report to modify the plans for a project to compensate for deficiencies. Soil tests help people above the ground understand what is below the ground.


Association of Construction and Development