Qiu, T. and Fox, P.J., 2008. Effective soil density for propagation of small strain shear waves in saturated soil. Journal of geotechnical and geoenvironmental engineering, 134(12), pp.1815-1819.
Qiu, T. and Fox, P.J., 2008. Effective soil density for propagation of small strain shear waves in saturated soil. Journal of geotechnical and geoenvironmental engineering, 134(12), pp.1815-1819.
I could not access the actual article, probably because of problems from this end (south Brasil). HOWEVER this modest amount of information SUGGESTS regression function (linear, quadratic, cubic??). Iff you have access to the original data (supplementary material perhaps), you might try running regression analyses and formulate any sigificant tendencies from there. Best wishes, may God guide all!