Abstract: The excavation and unloading of steep and inclined rock slopes can cause stress redistribution on the slope, especially in areas of soft rock or weak joints, which can easily trigger creep deformation and ultimately lead to slope collapse. For steep slopes with unloading at the toe of the slope, creep tests, displacement monitoring, and engineering geological investigations were conducted on the soft and mudstone interlayers inside the slope to comprehensively analyze the deformation and failure mechanism of the slope. Research has shown that after unloading at the toe of the slope, the weak mudstone interlayer undergoes progressive creep slip under the driving load of the overlying rock layer. When the weak interlayer is saturated, it enters the accelerated creep stage, increasing the risk of sliding and collapse of the overlying rock mass. The results have played an effective guiding role in controlling the instability of the slope, and have also verified the correctness and effectiveness of the joints in this study. The results have good reference and guidance for similar projects.

Key words: Steep Inclined Rock Slopes, Weak Interlayers, Creep Slip