If you have ever been curious about the Cone Penetration Testing (CPT) business, you have come to the right place. In today’s post we are going to take a dive into the basic concepts and what expanding into CPT can do for your engineering business.
Geotechnical Engineers and CPT Testing
Geotechnical engineering is a branch of civil engineering that focuses on the engineering behavior of earth materials. Geotechnical engineers have been using Cone Penetration Testing (CPT) for over 40 years to assist in the design and construction of foundations, embankments and other structures. The standardized CPT works by pushing a 55-60 degree cone into the ground at a rate of 1-2 cm per second and is used to identify the conditions in the upper 100 feet of the subsurface. The data compiled from this testing is valuable for assessing the subsurface stratigraphy associated with soft materials, discontinuous lenses, organic materials, potentially liquified materials (such as sand, silt and granule gravel), and predicting landslides or ground settling.
The cone resistance in conjunction with the friction ratio can also be used to determine soil types. While these results are often more accurate when referring to textbook soils, there are some major benefits to utilizing CPT techniques as opposed to drilling. In fact, there are a number of different advantages of CPT, including: economically friendly testing, as well as its ability to perform at a fast rate and effective in characterizing large volumes of soil without having to do a large number of laboratory testing. CPT is also accurate, eliminating the possibility of disturbances to soil samples and sample storage.
By leveraging CPT results, engineers can determine the best methods for several aspects of design and construction projects.
- Detect lenses, thin layers and sand stringers.
- Evaluate the thickness and extent of compressible soil layer.
- Determine the magnitude of consolidation settlements and the time rate of consolidation.
- Determine the stability of natural and man-made slopes.
- Assess the risks to the construction site, for example, earthquakes, landslides, sinkholes, soil liquidations, debris flow and rockfalls.
This information is invaluable for the geological engineer to understand before embarking on the design and construction of projects, such as bridges, roads, embankments and deep or shallow foundations. Not only is it imperative for the safety of site workers but also for the longevity and stability of the structure after completion.