When developing a new property or performing major renovations on an existing one, an important preparatory step is to have a geotechnical site investigation. These investigations are performed by geotechnical engineers or engineering geologists in order to obtain information on the physical properties of soil and rock around a site to design earthworks and foundations for proposed structures.
A site investigation can include such methods as geological mapping, geophysical methods and photogrammetry, or it can be as simple as walking around the site to observe the physical conditions. For almost all tests however, soil samples are taken.
There are two types of samples that can be taken: disturbed and undisturbed samples. A disturbed sample is one in which the structure of the soil has been changed sufficiently that tests of structural properties of the soil will not be representative of the conditions on site (also known as “in-situ”), and only some properties can be determined. An undisturbed sample is one where the condition of the soil in the sample is close enough to the conditions of the soil in-site to allow tests of structural properties of the soil to be used to approximate the properties of the soil in-situ.
Disturbed samples are usually taken from the site to be given laboratory tests that measure a variety of soil properties, such as moisture content, density, and particle size distribution. Undisturbed samples, which involve tests that have to be done on site, are usually done to measure the structure of the soil as well as its composition.
Soil sampling is an important part of geotechnical site investigation, but it is not the only step. Most site investigations will require a number of investigation techniques that require knowledge and skills that only well trained professionals are able to perform. If you have a property that you intend to renovate or do new work on, and you would like more information about what site investigation should be performed before work begins, you can contact EnviroTech for advice on 1300 888 324.