In this article (and video above), I solve a consolidation of clay practice problem that you will encounter during the FE exam. This example is of a geotechnical investigation at a proposed road construction site that contains a subsurface clay soil layer and looks at the consolidation of that layer.
This sample problem has been provided to us by PrepFE. PrepFE is one of the most effective FE exam self-study prep services out there and happens to be one of the most affordable too. It is an app that gives you access to countless sample FE problems to bolster your self-study efforts.
The Question Is:
A geotechnical investigation at a proposed road construction site spotted a 7 ft thick weak clay layer, 10 feet below the ground surface. On top of the weak clay layer, there is 10 feet of fill material. A sample was obtained from the drilling investigation and was subsequently sent to a lab for testing. The lab results for the weak clay layer and the fill material layer can be seen below. Assume building a road on top of the soil profile will increase vertical stress by 100 psf at the midpoint of the weak clay layer and the clay layer is a normally consolidated clay. What is most nearly the primary consolidation of the weak clay layer?