Geogrids

Geogrids

Geogrids can be used to increase the bearing capacity of foundations in weak soils. See Fig. 10.1. Geogrids distribute the load so that the factor of safety against bearing failure is increased. See Fig. 10.2. Due to the geogrid, the foundation load is better distributed. Hence the pressure on the weak soil layer is reduced. Pressure reduction occurs since the load is distributed into a larger area.

Figure 10.1 Geogrid

146

Geotechnical Engineering Calculations and Rules of Thumb

Figure 10.2 Load distribution in a geogrid For this reason, settlement can be reduced and bearing strength can be improved. Geogrids basically distribute the load in a m u c h more even manner. It is not advisable to use geogrids for major settlement problems.

10.1

Failure Mechanisms

The foundation can fail within the compacted zone. See Fig. 10.3. This could h a p p e n if the soil is not properly compacted. The foundation can fail due to failure of the soil under the geogrid. Geogrids need to be large enough to distribute the load into a larger area. See Fig. 10.4.

Figure 10.3 Failure in the compacted zone

Chapter 10 Geogrids

147

Figure 10.4 Failure within the weak soil layer

Reference Xanthakos, P. 1994. Ground control and improvement. New York: John Wiley and Sons.