Bearing Capacity from Hand Penetrometer Test

Hand penetrometers are a very gross test method. I would not recommend it for any test where an accurate bearing capacity was required, or any structure was to be built based on the data. Hand penetrometers are highly variable, inaccurate and susceptible to influence from the operator. No two operators apply the same pressures or action times consistently throughout the testing. Nor do they apply the same pressure through out the duration of one test or across multiple tests. Plus hand penetrometers have very limited operating ranges. Nothing tested would give you comparable accuracy or precision as you might see with a CPT or SPT.

Penetrometers are indeed a gross test method which produce inconsistent results for the reasons Guest cited, and this becomes readily apparent in the hands of an inexperienced operator. Needless to say, penetrometers remain the most popular of the methods used. Veterans of the technique know to apply pressure in a sinusoidal scheme having a period of around 2 Hz, with an amplitude roughly proportional to the compaction of the test material. Superior results are obtained by allowing at least 20 minutes for each test, with plenty of time between tests to mitigate operator fatigue and to avoid placing excessive stress on the instrument. Consistently following these guidelines will ensure repeatable, accurate results and years of service.

Recent advances in penetrometer technology have resulted in the development of competing methods, including this one. However, the stock penetrometer continues to remain the most popular tool in the operator's arsenal because it is a mature, "tried-and-true" technology that's easy to use even by the most inexperienced journeyman.