Vibroreplacement Columns

[roryg90]

I am looking at design options to strengthen the ground conditions for a proposed motorway embankment using vibro-replacement stone columns. There is a soft clay layer beneath the embankment which results in a deep seated slip failure upon loading of the embankment untreated. I am using oasys slope software and have managed to create a design using a square grid with 0.5 diameter columns spaced at 1.5m intervals which seems to work with an acceptable factor of safety. Do the triangular grids make much difference, cant seem to find anything to suggest the difference or benefit of the different grids?

 

[Guest262653]

It's all about the equivalent area for each grid type. I enclose a spreadsheet where you can see the difference in efficiency of the different grids (triangular, square and hexagonal).

 

[GeoPaveTraffic]

You also need to consider strain compatibility. If you aren't careful, the stone columns will be much stiffer than the surrounding soil and will attract more load than just the equivalent area.

Mike Lambert