There are many results about the interface test for geotextile
but the testing result of geogrid is lacking. This paper presents the contents and results of interface tests for uniaxial oriented geogrid and warp knitting geogrid; some useful opinions are provided. The interface friction coefficients between geogrid and sand-gravel and coarse sand and eluvial soil
are evaluated; and then compared with the testing results of the woven geotextile .