Introduction of Confining Effect of Geogrid-Reinforced Soil into Design Method

The authors have experimentally examined the reinforcing effects in geogrid-reinforced soil and evaluated it quantitatively. As a result, it was made clear that the reinforcing effects are expressed by the sum of the tensile effect and the confining effect. The tensile effect is due to the tensile force of geogrid. The confining effect is the effect that the geogrid is placed in the soil and restricts the deformation of soil. Therefore an additional confining stress is induced.In this paper, the confining effect was introduced into the design method to decide the arrangement of reinforcement, referring to “Design and construction manual of geotextile-reinforced embankments published” by Technical Memorandum of Public Works Research Institute. And some examples of calculation results were shown. In conclusion, the proposal method can reduce the amount of reinforcement about 10-30%. And some points which are requested to use the proposed method were mentioned.