Effect of Surface Roughness on Soil-Geogrid/Geotextile Interface Shear Strengths

• Published in: International journal of geosynthetics and ground engineering Vol. 10; no. 3
• Main Authors: Chai, Jin-chun, Saito, Akinori, Hino, Takenori
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.06.2024
• Subjects: Building Materials; Engineering; Environmental Science and Engineering; Foundations; Geoengineering; Hydraulics; Original Paper; Direct shear test; Geotextile; Surface roughness; Interface shear strength; Geogrid
• ISSN: 2199-9260; 2199-9279
• DOI: 10.1007/s40891-024-00558-y

To get some insights on the effect of surface roughness on the interface shear strength, interface direct shear tests were conducted using two sandy soils (M1 and M2) and 4 geogrids (GG) and 5 geotextiles (GT) with difference surface roughness. The normalized surface roughness ( R n ) and the asperity ratio ( AR ) are used as indexes for surface roughness. R n is the ratio between average asperity height and D 50 of a soil, AR is the ratio of the half spacing between two adjacent asperities and D 50 . For interface friction angles ( δ ), the test results indicate that R n (> 0.06) had a positive effect on increase δ and resulting in δ  >  ϕ (internal friction angle of a soil). There is no clear tendency of the effect of AR on δ . For (apparent) interface adhesion ( c a ), there are different tendencies for M1-GG and M2-GT interfaces. For M2-GT interfaces, there is a tendency of increase c a with increase of R n value. While, for M1-GG interfaces, for the conditions tested, there is a tendency of increase c a with decrease of AR value. Further, in terms of δ / ϕ and c a /c (cohesion of a soil) ratios, generally, the average values for M2-GT interfaces are higher than that of M1-GG interfaces. The reason considered is the interaction between soil particles and the surface fibers of the GTs, i.e. the soil particles plowed on the surface of GTs.