I'm putting in a small retaining wall made of 6x6 timbers. I need to secure them with 2' rebar driven into the ground. On the second image I circled the problem area. A piece of rebar will need to go into this corner, but it's too close to the marked gas line, which means I need to dig to find the actual location before doing anything else. I dug down over 2ft, about 3 feet across, no gas line. I understand it can be deeper, or further away from the locate. It could also be below the pavers. I'm tired of digging. I'm thinking instead, I'll dig the trench for the timbers in this location 6" deeper, fill with concrete, and set the timbers in the wet concrete with 1' rebar already driven into the timber. In the 3rd photo, the grey is concrete and the brown is limestone screenings. The limestone will already be in place and level before pouring the concrete. Would this be an ok solution? Do I need to worry about frost heave? This is southern Ontario.