Sand cone (replacement) test is normally carried out to determine the in-situ and compacted density of soils. This testing method is not suitable for granular soils with high void ratio because they contain large voids and openings which provide an access for sand to enter these holes during the test. Moreover, soils under testing should have sufficient cohesion so as to maintain the stability of the sides of excavation during the excavation step in sand cone (replacement) test. In addition, organic or highly plastic soils are also considered not suitable for this test because they tend to deform readily during the excavation of holes and they may be too soft to resist the stress arising from excavation and from placing the apparatus on the soils.
This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.
If you have a query, you can ask a question here.