This query would be better posted over in alt.home.repair.
Simply disturbing soil will not bring about a leak in a basement -- damage
to the wall, changes in water flows, hydrostatic pressure, and so forth are
all likely culprits.
Your first step here is to determine just what the cause of the water
infiltration might be -- your post did not have much in the way of details
about the problem area, so it's tough to really tell. Once you have
determined how the water's getting in, then you can select the right
Cement block foundations can use things like DryLok to seal seapage off,
while others (as well as block based setups) can use products like SaniTred
to totally water proof the walls (supposedly -- never tried it). There is a
type of cement that will expand as it dries, typically sealing cracked areas
that are leaking. Both DryLok as well as expanding cement are available at
most large home improvement stores (such as Home Depot and Lowes).
Once a basement starts to leak, the problem will only get worse if the right
solution is not put in place early on -- I speak from experience on that
one, as we're battling a major problem in our basement (stone foundation)
that weren't so bad when it first started.
Take it by the numbers -- figure out exactly where the problem is and THEN
devise your solution.