How to confirm stone columns where installed successfully? 1

[pelelo]

Engineers,

I am involved in a project which the original geotechnical investigation recommended stone columns due to the soil conditions.

Client is asking to the geotechnical consultant (not to the stone column contractor) if there is a way to confirm if the stone columns really densified or improved the ground.

It is my understanding that running a plate load test could be an option.

Also another option I think could be to run SPTs nearby the original SPTs and compare.

Any thoughts?. Thanks.

 

[LittleInch]

Maybe obtain this study?

https://www.sciencedirect.com/science/article/abs/pii/S2214391224002265

Also https://www.issmge.org/uploads/publications/1/31/1997_03_0036.pdf

Did you do any looking online?

 

[EireChch]

In soft soils, stone columns offer very little improvement. Only in generally firm CLAY and granular material do they offer some improvement in the ground between the columns.

A plate load test on top of the column on confirms the E' of the column material. This can be checked against the design assumption.

The best verification of a stone column improved ground is by a zone load test , typically a 2-3m square foundation placed on the columns. The position of the ZLT in relation to the column can be up for debate i.e. ZLT centered over a column, or placed on ground between columns