Retaining Wall - Stones and Support?
This idea should draw some flak from the hard core concrete workers but here goes. Go ahead and put in your sidewalk ,figure 4 inches in the walk area ,but make the walk 40 inches wide , so a poured wall, 8 inches thick, the heighth you need,leaning slightly to the house can sit on the walk so to speak, only have piers going down to the three foot level every 10 feet , and have the crete footer (the walk) at least 8 inches thick. The whole walk and poured walls will be depending on the deep piers for anchoring. You can put in three inch pvc pipe for spreaders and to let out trapped water. You can use half inch osb board for form work,but buy the longest 2x4's available and install on edge with threaded rod going through the 3 and a half inch way . First 2x4's two inches from bottom of osb boards and 12 inches up for the next row and 12 on up. Keep your crete a number 4 slump so you don't get the pressure. Run a string to keep your wall straight at the bottom, and stick short lengths of re-bar in walk where wall sets. The secret in a wall pour is to have plenty of wall ties (bought from a concrete company) or buy threaded rod, but you need plenty of them, at least within a foot from each other in your case. But very close to the bottom with a furring strip jamming the osb board with nails in the concrete. So there, and fine tune please.