Chetu, your question looks more simple in appearance than it is. You will be modeling Earth Push, and if we continue using the procedures derived by Coulomb is because in 3 centuries we have not been able for something as general show useful results in practice. Then, if you admit some -reasonable, conservative- internal angle of friction and some specific weight for your saturated soil, you can derive the active push you want by Coulomb's method either by closed form formulation (the case would be covered for example by our spanish NBE AE 88 provisions) or directly by analysis of equilibrium in the wedges behind the wall. I have posted a sheet in the Mathcad Collaboratory that would permit such analysis for any analytical backfill surface.