Example of cone penetration tests on clay ground

The figure shows an example of in-flight cone penetration test results. Cone tip resistance, Qc, total resistance including tip resistance and skin friction, Qt, and penetration rate, v, are plotted against depth in the figure. Some 260 mm deep uniform clay bed were prepared by consolidating clay slurry at vertical pressure of 300 kPa in the laboratory floor. Since cone penetrometer (10 mm diameter) was intruded shortly after the centrifugal acceleration reached 100 G, undrained strength of the clay bed was considered to remain unchanged. But due to the high hydrostatic pressure in the accelerated model, tip resistance was observed to increase slightly with depth.