If you are interested in dynamic Soil-structure interaction you may try to find NIST Report GSR 21-971-21 “Soil Structure Interaction for Building Structures” for simplified calculation of spring stiffness. If you need more insight in the topic I recommend the classical book of Wolf "Dynamic Soil-Structure Interaction". The more recent book of Wolf & Deeks "Foundation Vibration Analysis" provides a good approximate method for calculation of frequency-dependent impedance.

Dear Muhammed,

I don't know if you mean vertical or horizontal soil spring, So, I attached both of them

I hope this helps you 

good luck

Dear Sir,

pl check it.

http://pwp.net.ipl.pt/alunos.isel/33082/coeficientesRigidez/paper.pdf

You can see Bowels, which give approximate eq . k = 120 q, q: is soil bearing capacity.

dear Muhammad

attached reference may be beneficial for you

It is a good  reference DR Amjad.

Respected all,

Thanks for your replies :)

Dear Ahmed Ebid

Could you share English version of material for Kh?

Thanks a lot.

Dear Debendra Neupane ,

Please find the attached documents, I hope they will be useful

regards

Dear Ahmed, thank you very much.