I started an analysis to study the affect of rainfall infiltration on slope but it take too much time.
I feel your pain Sohaib, coupled flow deformation takes a lot of steps and a long time, ESPECIALLY for transient uncoupled flow. In my experience several hour run times on a fast multi core computer are typical for this type of analysis.
Keeping as much of the problem linear as you can will help. Mohr-coulomb model and simplify the suction-permeability curve, cut the curve off at Kr=0.01 so the permeability doesn't not drop too much. Trying to make the mesh or parameters so that the changes across one element in the model are as small as possible. Try to find the optimum reduced model/mesh size. Simplify as much as you can. Once it's working as you expect, then add complexity and let it run over night.
More obviously faster computer. more memory, and run locally.
Martin
Hello Sohaib,
Martin before me gave some nice tips.
I would add, check if you have large differences in permeabilities, too. Numerical analyses do not really "like" differences between the high and low permeable soils to be in the order of 1E6 and larger.
If you have a material that is with a very (very) small value for permeability consider switching it to non-porous as for the geotechnical water flow analysis, that layer will not really affect the water flow.