Studying and investigating the effect of cross joints on the overturning rupture of rock slopes with inverted layers

Toppling failure is a common failure mode in natural and artificial rock slopes, which has always been associated with serious injuries to humans in road trenches, tunnels, dams, and mines. In this research, it has been tried to investigate the effect of cross joints with inverted layers on the toppling failure of rock slopes and horizontal displacements on the slope surface, in this regard numerical modeling using discrete element software. (UDEC) has been carried out in the rock to study the toppling failure mechanism, surface displacements, investigation of yield levels and the formation of tensile cracks, and parametric studies for cross joints with inverted layers and with different numbers in the rock slope. A total of six rock slope models were analyzed (three different models for the case of one cross-joint and three other models for the number of cross-joints). The results of this research show that the mechanism of failure in this type of slopes is stepped, unlike soil slopes, and when the first tensile crack reaches the surface, the toppling area is formed. The presence of cross joints causes more instability, which will increase the surface displacements much more compared to the model without cross joints. The length of the rock layers and the number of joints can simultaneously have their effects on toppling failure; The speed of movement of the layers also confirms this. The sliding zone is also formed in these models, which resists the toppling failure to a certain extent, so it is necessary to know these zones to stabilize the inverted rock slopes.