Lot of literature are there related to research on stabilization of soft clay using stone column. I suggest you to search in research gate itself by stabilization of soft clay using stone column. Also, you may try from google search..

if you have any of this please send it

The question is also, why do you want to use stone columns to stabilize the soft clay layer? Have you already assessed that this is the best solution in your specific case? What mineralogy of clay is it?

Find attached the paper that is relevant to your work. I recommend you to read this paper for your reference..