How Does Geogrid Reinforcement Actually Work?

From building a simple wall that is 3-feet (0.9m) in height to walls that are over 50 ft (15.3m), we put a lot of faith in these layers of geogrid reinforcements that are installed in and behind the Allan Block units.  So how do they do it?  The answer lies in how the soil interacts with the geogrid.

The Chinese were on to something when they were building the Great Wall of China.  As the stacked the dirt the realized that as the pile grew higher it also grew wider.  They needed a way to hold the dirt in place as it was stacked higher.  They used Tamarisk branches to hold everything together like you see roots do for a living tree.  The dirt gets trapped in the opening and cannot move.  Obviously, we have evolved from using branches and now have manufactured geogrid reinforcement to serve the purpose, but the concept is still that same.  The dirt gets trapped in the opening of the geogrid and cannot move.  By placing multiple layers of geogrid behind the wall it hold the entire area together as one structure.  We refer that to a composite mass consisting of block, rock and soil all held together by the geogrid reinforcement. 

 

So the concept is simple.  The longer your geogrid layers the more mass you have in your structure. Therefore, when you have that tall retaining wall the layers of geogrid are longer to withstand the increased pressure due to the height.  There is a great video here that explains how the concept works.  http://youtu.be/BQ2w6A23ElQ

For more infomation on geogrid or other reinforcement options, visit our website at allanblock.com