I wanted to consider building on poor land, the idea is to use drainage piping to build housing and business premises. Just a general consideration. I know others consider sandy soil areas are poor soils to build on, again the difficulty of initial soil clearance. I thought of foundation raft treatments but noted uplift might be possible. With a project in Greece they used previously mentioned elsewhere stone columns as a foundation support for sunken road tunnel sections. I understand a success and know this would lead to a less differential settlement foundation. Back to the land alteration you can use localised materials as possible soil replacement. I know on site soil particles can be investigated, can have economical benefits as well.