Determination of the Parameters of the Interaction of the Crushed Stone-Geogrid System

Objective: the purpose of the work is to experimentally evaluate the shear strength and interface parameters of the crushed stone–geogrid system, as well as to establish the influence of geometric and mechanical characteristics of geogrids on the effectiveness of reinforcement of crushed stone material. Methods: the study was performed on the basis of large-scale shear tests conducted using a direct shear laboratory installation. The tests were performed for non-reinforced crushed stone and “crushed stone–geogrid” systems at various levels of normal voltages. According to the test results, the coefficient of interface interaction and the parameters of shear strength (angle of internal friction and engagement) were determined. The data obtained were compared with the geometric and mechanical characteristics of the studied geogrids. Results: it was found that the use of geogrids leads to a change in the mechanism of resistance to the displacement of crushed stone, which is expressed by the redistribution of the components of shear resistance. The values of the interface interaction coefficient are in the range of 0,70–0,86 and depend on the type and rigidity of the geogrid. It is shown that an increase in the interaction coefficient correlates with an increase in the thickness of the edges and nodes, as well as with an increase in the rigidity of the geogrids. Practical significance: the results obtained can be used in selecting the type of geogrid and assigning the design parameters of reinforced crushed stone foundations and ballast layers of railways. The established relationships between the geometric parameters of geogrids and their reinforcing efficiency make it possible to increase the validity of engineering solutions and refine the computational models of the “ground–geogrid” interaction.