MOST likely, the reason(s) a basement wall can crack-leak-bow is from one OR more of following---
1) the SOIL that was used as Backfill against the outside of the wall settled/compacted which causes a spring-like lateral force against the way and caused the wall to crack-leak-begin to bow inward. Most builders use the SAME soil that was excavated to backfill, a few will use a LITTLE gravel-peastone BUT, still backfill w/mostly the same soil which was excavated.
2) the backhoe/equipment operator didn`t know and/or didn`t use any-enough CARE when backfilling heavy/large amounts of same soil against newly built walls. Walls where steel reinforcing rods were NOT used or sometimes, bsmt floor was NOT poured/installed and they still backfilled. Thing about using heavy equipment ALONE is that the WEIGHT of the equipement itself, when operated near/along basement walls can/could cause a wall to crack/bow.
3) the soil that was used for backfill finally got its first few soaking/rain and its always possible that, when clay is used as backfill against bsmt walls it, expands when it gets wet and then, contracts. THIS kind of Lateral-SOIL-PRESSURE OFTEN causes new/old wall(s) to crack,leak,bow inwards.
4) Tree ROOTS, roots can grow along/against outside of basement walls and certainly could cause a crack, leak, help push a wall inward.
5) some cracks/leaks can be caused from underground vibrations, again, from heavy equipment being operated close by, like in the street or even from house being close to a highway, yup.
Don`t believe me, fine...read this...
http://www.bobvila.com/HowTo_Library/Why-Foundations_Fail-Foundation-A2095.html
take time and read it....
for instance, see --Compaction-- 2nd para
"The problem is that the PRESSURE from the compacting process gets transmitted THROUGH the Soil to the WALL. Basement walls have been known to CRACK or fall over while earth is being dumped against them OR,compacted around them; so foundations should ALWAYS be BRACED BEFORE Backfilling.
AFTER compaction, SOIL is under compression like a spring and CONTINUE`s to PUSH Against the foundation as it tried to expand.......in practice sands and gravels densify or compact more readily than silts or clays, creating LESS of this springlike FORCE--one more GOOD reason to use them for backfilling!!!!
--Careful On Construction Site--
"When there`s a heavy load on the ground next to a foundation, some of the PRESSURE is transferred to the WALL.During construction, bulldozers and trucks that come near a basement wall can add enough surcharge Pressure to damage the wall. A NEW building being built next to an existing basement can also INCREASE the Underground PRESSURE and DAMAGE the EXISTING foundation..."
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