While many people have never heard of it, geotechnical drilling is a crucial step in preparing a site for the construction of a large building. Before the construction of a new building can begin, soil samples must be taken in order to determine various qualities about a site, which helps in making decisions about what can (or at least should) be built there. While the purpose of geotechnical drilling is the same, there are many different ways to go about collecting a sample. Different methods are chosen for a variety of different reasons, including the type of soil being tested. For instance, frozen soil in Denver would be collected much differently than the warm ground in sunny Spring Hill. Geotechnical drilling samples can be either disturbed or undisturbed, depending on how they are collected.
Disturbed samples can be taken in a variety of ways, including machine or hand driven augers and shovels. A hole or a pit is carved out to a predetermined depth and a bit of the soil is examined, usually by an engineer or geologist on site. Not much can be done with a disturbed sample. Only if the tests being done are not in relation to the structural stability of the site, can a disturbed sample be taken. However, once the soil has been altered, it can no longer be relied upon for more critical examinations. In these cases, other approaches must be taken.
If engineers need a more specific glimpse of what a site can stand, more complicated procedures must be undergone in order to get a sample that hasn’t been altered by machinery or other equipment. These are referred to as undisturbed samples and are a lot more reliable for structural information than their disturbed counterparts. Collecting these kinds of samples is more difficult; requiring the use of specialized equipment such as Shelby Tube or piston samplers.
Even though they aren’t something you hear about every day, these sorts of investigations are happening all around us and are very important to making sure that a newly-started project doesn’t end in disaster. In a developing area such as Spring Hill, geotechnical drilling is a daily occurrence, but without performing this seemingly small task, the city may literally collapse.
*Disclaimer: The views expressed here are those of the authors and do not necessarily represent or reflect the views of Amdrill Inc*