sinking slab has been slab jacked 3 times. sinking again

We built a new house 20 years ago. We moved in and in the first year the back corner of the family room was sinking. Builder said it was just settling. We ended up having to have it slab jacked three times. In addition the other side of the room by the door to patio sank also. What caused the4 problem and how can we fix it for good.. There is a berm behind the house. It is a large bank and we have had two sets of drains put across the whole back of the whole house.
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The only conclusion that can be drawn from the data is that the support for the lab is compressible. You need to get a pit or a borehole to find out what is down there, before doing any more jacking.
If you look at a terrain map you might be able to guess what is going on: maybe the berm is to control a river or stream, and your plot encroaches into the stream deposits (peat?).
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On Thursday, 15 January 2015 21:44:03 UTC+7, Kathy wrote:

The only conclusion that can be drawn from the data is that the "support" underlying the slab is compressible. You need to get a pit or a borehole to find out what is down there, before doing any more jacking.
If you look at a terrain map you might be able to guess what is going on: maybe the berm is to control a river or stream, and your plot encroaches into the stream deposits (peat?).
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