I've been having many problems with the land around the house. I think my house land has sunk something like 1 meter now. I had to add 3 more flights of stairs just to get to the house. Fortunately the house is on beam and is not sinking. But everything not connected to the house is cracking and sinking. It really causes problems with the driveway and other areas. Will the sinking ever stop or will I have to add another 3 flights of stairs in 10 years. I really don't know what to do because I had to redo the piping under the house and add 1 meter to the pipes. How far will it sink? Will BKK one day be under water?

How about pulling a load of topsoil up down to the hard stuff and adding some of that red make-up clay (bakerite is it?), and then bunging the original topsoil back on after. Or perhaps a load of rebar meshing on the level it is now and then a mixture of clay and topsoil?

Bangkok is definitely sinking but a metre in 10 years sounds very high. Whereabouts in Bangkok are you and are you near any industrial complexes that are using a lot of well water?

Putting a load of topsoil down to the "hard stuff" may be probhibitively expensive as the first sand is around 20 metres, which is normally where piles are driven to. The bottom of the Bangkok clay is around 80 metres. As there no laterite within a 100km of Bangkok, this will also be expensive and keep going down anyway.