Investigating the behavior in the interface of the filter soil material-the core asphalt concrete using direct shear apparatus-Case study: Mijran dam

Recently, the advantages of using of asphalt concrete in the core compared to clayey core have increased the application of core asphalt concrete in embankment dams. Due to the importance of interfacial behavior the asphaltic core and soil filter in the stability of these dams and the need for a more detailed investigation of the complex behavior of materials in the core- filter interface, in present research, interfacial behavior of soil filter and asphalt core in the Mijran embankment dam (Mazandaran province) was investigated. For this purpose, a direct shear apparatus in the large scale is used. Soil materials , including clayey gravel (GC) and poorly graded gravel (GP), are according to the grain size distribution used in Mijran dam construction . In this research, the influence of factors such as compaction percentage of filter material and shear rate were investigated on shear strength and interlocking parameters ( dilatancy angle and shear stiffness) , as well as interaction ratio in the soil of filter and the core asphalt concrete interface. In this investigation, the ratio of the interfacial friction angle of soil material- asphalt concrete to the soil materials friction angle was defined as the interaction ratio. According to the findings, upon increasing the compaction level, the increase amount in the interaction ratio in the interface GP material was higher compared to the GC material in the interface. On the other hand, the influence of the shear rate on the interaction ratio was similar in both the GC and GP materials in the interface.