Abstarct: We deal with rock slopes in many different engineering activities, which require cutting in stone. For example, projects of transportation systems, railways, and open mines are among these activities. Meanwhile, the expansion of vital arteries and the construction of new roads always increase the risk of geological hazards and significantly landslides. Due to the importance of maintaining safety during operation, the risks of collapse and rock slope stability should be investigated. In some cases, we are dealing with slopes that have collapsed, and due to the construction of structures near the block slide, stability of the slope and block slide under dynamic loads and post-collapse behavior are of great importance. In the meantime, studies related to the post-collapse behavior of the raveling slope have taken a small share of the studies carried out in the field of analysis of slopes. In this thesis, an attempt has been made to address this issue, and for this purpose, a block slide that occurred at km 28 of the Tehran-North Freeway has been studied. In this research, the studied slope was modeled using numerical software FLAC^3D, and also the shape of the collapse that existed in the slope before and after the collapse was simulated. This way, the block slide parameters and the discontinuities involved in this slide have been calibrated and estimated using the back analysis. Due to the limitations of the FLAC^3D software in analyzing the post-collapse behavior, the PFC^3D software, which can investigate the post-collapse behavior of the mass, has been selected to use. The parameters in the FLAC^3D software have been re-estimated in the PFC^3D software for calibration and accuracy and have been recalibrated. After simulating the collapse in PFC^3D software, the block slide behavior was investigated by creating four different accelerations to the studied slope. Accelerations have been applied baxsed on a fraction of the baxse acceleration of the area (0.35g). In this research, in addition to 1/2 0.35g, which is used to analyze structures such as trenches, the values of 1/4 0.35g and 2/3 0.35g and all the baxse acceleration, i.e., 0.35g, have been evaluated. In the end, the freeway route built in the block slide's vicinity is examined after the re-sliding that occurred due to the applied accelerations. The obtained results indicate that the freeway path is wholly blocked under accelerations greater than 1/4 0.35g; from this, the block slide at 2/3 0.35g and 0.35g accelerations also cross the width of the freeway.