Mad Mike
Geotechnical
- Sep 26, 2016
- 220
I have a major bulk earthworks project commencing in the next few months and value engineering is currently underway.
A costly aspect of the bulk earthworks is constructing high shale fill embankments over valley bottoms underlain by high plasticity transported clays. Rather than remove these clays (they are thick), I designed the new embankments to be constructed off a very high tensile strength (800kN/m) basal geogrid.
I've since been approached by an established engineering firm marketing cellular geogrids, comprising perforated geocells with very light uniaxial grids. The ultimate tensile strength on their uniaxial grids is just 50kN/m, however, I am being assured that by packing these cells (200mm depth) with a high quality crushed stone, the tensile performance will be every bit as great as the 800kN grids I had specified.
I'm having a very hard time believing this. My question is, have any of the geotech. guys used cellular geogrids as a single basal reinforcement layer to high fill embankments? I can picture it working in a number of applications, but a single layer at the base of a high fill embankment (40 - 60 feet) over a fat clay foundation is not one of them...
Thanks in advance,
Mike
A costly aspect of the bulk earthworks is constructing high shale fill embankments over valley bottoms underlain by high plasticity transported clays. Rather than remove these clays (they are thick), I designed the new embankments to be constructed off a very high tensile strength (800kN/m) basal geogrid.
I've since been approached by an established engineering firm marketing cellular geogrids, comprising perforated geocells with very light uniaxial grids. The ultimate tensile strength on their uniaxial grids is just 50kN/m, however, I am being assured that by packing these cells (200mm depth) with a high quality crushed stone, the tensile performance will be every bit as great as the 800kN grids I had specified.
I'm having a very hard time believing this. My question is, have any of the geotech. guys used cellular geogrids as a single basal reinforcement layer to high fill embankments? I can picture it working in a number of applications, but a single layer at the base of a high fill embankment (40 - 60 feet) over a fat clay foundation is not one of them...
Thanks in advance,
Mike