Reinforced soil
Reinforced soil
(OP)
while constructing a reinforced soil wall
is there any other reason for providing Machine direction(MD) of grid (reinforcement) wrt face of the wall for connection.
what if MD reinforcement provided parallel to the face of wall
is there any other reason for providing Machine direction(MD) of grid (reinforcement) wrt face of the wall for connection.
what if MD reinforcement provided parallel to the face of wall





RE: Reinforced soil
RE: Reinforced soil
I'm referring to typical HDPE uni axial grids
principal strength direction to be kept perpendicular to face of the wall.
what is the purpose/mechanism behind it
can any one clarify this.
thanks
RE: Reinforced soil
RE: Reinforced soil
EIT
www.HowToEngineer.com
RE: Reinforced soil
The Cross-Machine Direction (CMD or XD) is across the width of the roll and most uniaxial geogrids have a significantly lower strength in the CMD than the MD (often less than half). So placing geogrid in wrong direction will result in an insufficient reinforcement strength and affect the factor of safety of the wall.
RE: Reinforced soil
www.PeirceEngineering.com
RE: Reinforced soil
contractors want always find the shortcut to finish the job very quickly and if there is no proper QC on site failures most propably will happen as showed you by Penc.
however sometimes consider the dimensions of the wall you might want to use a bidirectional geogrid that can be unrolled along the wall. you need to consider the following:
- a bidirectional geogrid is about 30-40% more expensive than a monod.
- the wall cannot be very high because the lenght of the reinforcement has to be less than the size of the roll. usually ggr comes in max 4m wide and considering a rule of thumb (L=0.7H - BS 8006) you can use this method for wall not higher than 5.7m
usually for very small walls I saw geotextile nonwoven being used. it is fine but remember that geotextile is not consider as reinforcement because does not show any long term properties, it creeps (stretches under constant loading) and does not have any tensile strength after couple of years.
if your wall is a temporary wall with a high not more than 5m without any restriction deformations, use a geotextile woven at bidirectional.
otherwise ggr monodirectional.
hope it helps
RE: Reinforced soil
Good post except for the comment that geotextiles are not considered reinforcement. This is completely false. The highest strength geosyntehtic reinforcement on the market are geotextiles (less open area means more strength) and are used for reinforcement applications.
Nonwoven geotextiles are not reinforcement geotextiles but don't lump all geotextiles into the same pile, they are vastly different. Nonwoven vs. woven, PET vs. PP, yarn vs. fiber, etc. all factor into what each geotextile should be used for. Some are used for drainage, some for separation and some most definitely are used for REINFORCEMENT!