retaining-walls - Question and answers

As a landscape architect, I'm working on a project where we need a 2-meter high retaining wall made of concrete blocks. The soil is clay-rich and tends to retain water, so I'm worried about hydrostatic pressure. I've already planned for a gravel backfill, but I'm unsure about the specifics of weep holes, drainage pipes, and whether to include geogrids or other reinforcements. Any detailed advice would be appreciated!