That is the wedge of soil you will be holding up with the wall, this acts as one single mass.
Start at the base of the wall and draw a line all the way up to final grade equal to the angle of repose (angle the soil naturally won't cave in at) for your particular soil (say 45 degrees for arguments sake).
Retaining walls are both the wall itself and a wedge of soil behind it. With the newer colors and finishes we engineers are even able to satisfy ornery architects. Much about these walls has just recently been learned and now, with proper installation, they make a much better alternative than the concrete retaining wall as shown above. SRWs (See ) have become much more competitive now that they have beaten the bad rap from past years. If I do nothing to the block but have them just stacked and mortared together then should I wait to backfill between the dirt and wall until after the slab is poured ? There will not be a concrete slab poured on the inside against the block for maybe until next spring/summer. Should I pour the first few layers of block with concrete or is it really necessary ? There is no vertical rebar.too late for that. The gravel will help from any freeze heaving ect. With the deepest part being around 5' deep (half of that is undisturbed dirt) and then backfilled with gravel my question is would you do anything special to the block to secure it ? Most of the other dirt around the house will be approx. I also want to strengthen the below grade block wall with something like a 1/4" thick Quickrete 5000 spread over it and then seal and then gravel backfill. However the space between the concrete block wall and the dirt will be backfilled with gravel. This deepest place will have about 5' of dirt high. By the way the lines are where the water and electric will be entering. This pictures shows the footer next to the deepest wall of dirt where there will be a concrete block wall placed.