Pullout Test Study on Interface Friction Characteristics of Reinforcements with Red Sandstone as Filler

Abstract

In order to study interface friction characteristics between reinforcements and red sandstone, pullout tests were carried out. Three reinforcements were chosen: 2.2 mm gabion mesh, 2.7 mm gabion mesh and 70RE geogrid. The pullout coefficient, cohesion and friction angle of these three reinforcements were obtained. The curves of pullout friction coefficient and normal stress, shear stress and pullout displacement were established. Test results showed: Pullout friction coefficient decreased nonlinearly with the increase of normal stress; When the pullout displacement reached a certain value, shear stress tended to be stable, and most of which presented a peak value; Pullout coefficients of different reinforcements differed greatly; Double twisted hexagonal gabion mesh had better interface friction characteristic than geogrid; The smaller the diameter of gabion mesh was, the better the interface friction characteristic would be; In general, the pulling-out process of reinforcements could be divided into three stages: initial stage, developing stage and yield stage. During the test, special clamping system was installed to limit lateral deformation of specimen.