Abstract: In order to explore the reinforcement mechanism of geogrids, three geogrids of different mesh sizes were designed. The strain-controlled triaxial instrument was used to carry out the unconsolidated undrained triaxial shear test of reinforced sand. The effects of mesh size of geogrid, number of reinforced layers and confining pressure on the strength characteristics of the sand were investigated. The test results show that when there is no reinforcement, the sand is mainly manifested as the bulging failure of the middle and upper parts. With the increase of the number of reinforced layers, the destructive forms of the sand are successively transformed into the middle bulging failure and shear failure. The partial stress-axial strain curve of plain sand and reinforced sand is characterized by strain softening. Geogrids of different mesh sizes have different effects on the strength characteristics of the sand, and when the mesh size of geogrid is $ 3 \, mm \times 3 \, mm $, the reinforcement effect is similar to that of hardened geotextiles; when the first layer of geogrid is reinforced, as the mesh size of geogrid decreases, it has little effect on the strength of the sand. When the second and third layers of geogrid are reinforced, the smaller the mesh size, the better the reinforcement effect. Adding a geogrid to the sand can effectively increase the cohesion of the sand, and when the mesh size of geogrid is small, the geogrid can also improve the internal friction angle of the sand.
Keywords: geogrid reinforcement; mesh size; strength characteristics; failure morphology; triaxial test
合肥工业大学学报自科版