The retaining wall is holding level backfill, but if I need to design a 12ft maximum height (from top of footing to top of retaining wall), is there a limiting criteria on how height I can go with the masonry wall stem?.
If you wish to build a simple gravity wall with masonry, a rule of thumb is the base (and all wall) width must be at least 1/3 the height. So for a 12 foot high wall it must be four feet thick (front to back) as SOLID MASONRY and all mortared together in one solid block. That means all cavities must be filled with mortar. If any saturated backfill or inclined backfill, that requires an even thicker wall front to back.
In answer to XR250, no design, but I've built several retaining walls using rocks and boulders, no mortar. Height to 8 and 10 ft. Cheated a little with front face laid back a little. Numerous large concrete block walls with significant sloping front face can be found in Dubuque, IA. Cuts way down on that 1/3 requirement. I did one such with height about 25 ft. laid well back against a hill with sloping backfill, designed, yes gravity. Most ready-mix concrete plants these days save the remains of each load in forms roughly 3 x3 x 5 ft. which make pretty neat gravity walls and can be run up higher than the 1/3 limit by using geogrid, again designed.
