It has been observed that a significant number of slopes collapse either during or immediately after it rains. Even though it has been stated that the conditions that lead to these failures are caused by a rapid rise in pore-water pressure due to rainwater seeping into the soil, the important factors that lead to slope failures have not been explained well enough. This is because rainwater seeping into the soil causes a rapid rise in pore-water pressure. Several laboratory tests were carried out on modeled sandy slopes with the purpose of determining how the process of slope failure that is brought on by precipitation actually begins. Small-scale models of slopes failed the tests for one of two reasons: either water seeped up from the side or rain was forced to fall on top of the slope. Aside from measuring the pore-water pressure, changes in the volume of water in the soil as well as the movement of the ground itself were also measured. The studies showed that when the soil moisture level around the base of the slope reached virtually complete saturation, even when other regions of the sliding mass were still just half wet, the slope was more likely to fail. Additionally, the pattern of failure was recorded, and the results were compared with the outcomes of failure with and without the presence of vegetation cover, in addition to the shear strength parameters.

Keywords: Slope Stability, Strength, Vegetation, Direct Shear Test