Ground improvement under an existing building 1

[clarke1973]

Does anyone have any experience with this?
We have a client with a processing facility in the Middle East. A couple of the smaller ancillary buildings have experienced some significant settlement recently (> 100mm). The cause is not yet known and the original soil investigation report is apparently not available. Obviously we will be engaging a geotechnical expert to investigate, but in the interim I wanted to have a look at possible methods of ground remedial works to give the client an idea what to expect cost wise.
would greatly appreciate any thoughts or advice.

 

[dik]

Do you know the type of soil, and, the magniude of the loading, and, how long has the soil been loaded?

Dik

 

[clarke1973]

dik,
Information we have so far is that the soil consists of silty sand layers with coral deposits. The water table is understood to be +4m below ground.
The main processing building (single story, steel framed open warehouse type structure) is on isolated pad foundations with the ground slab 'on grade'. It is unknown yet whether this building has any problems. The smaller single story concrete buildings, which have settled are on raft foundations.

 

[dik]

Have you engaged a geotekkie? familiar with the area and soils?

Dik

 

[oldestguy]

A common techniques is done in cases where, not only used for raising things back up, but compacting loose ground is called compaction grouting. Pipes are driven to various depths and a cement grout is pumped there,sometimes with the pipe gradually being withdrawn. One has to keep careful watch on the surface elevations to control what happens. Only well experienced contractors should be used. One must also be watchful of any existing drainage pipes, such as those carrying waste water. It is hell to pay if they accidentally fill your sanitary sewer with grout. Other damages can result,such as raising an area well away from where you think it is going. Another thing, paying for the grout quantity on a unit price basis can really hit you, especially if the estimated quantity is exceeded in order to accomplish the job. Do not use a contractor who is a "slab jacker", since that experience is no where close to the skill needed.