Effect of tension crack on slope stability in rainfall conditions

Landslides often occur due to cracks at the top slope. Natural factors are a common cause of crack formation due to climate change in weak soil layers. Cracks can be a unique path for rainwater infiltration and trigger slope failure, and it is necessary to study the effect of tension crack on slope stability. Rainfall, hydrological conditions, and soil layer formations of the slope are the factors that cause landslides. Parametric studies were carried out to study the impact of tension crack with scenarios in crack depth, crack width, slope angle, intensity, and duration of rain. The numerical analysis used three different rainfall conditions, namely 5, 15, and 25 mm/hour and the groundwater level (GWL) position at the foot slope. The numerical analysis included the tension crack at the top slope with the topsoil layer of silty with low plasticity. A 2-D numerical model for saturated-unsaturated soil seepage and slope stability using SEEP/W and SLOPE/W. The results showed that increasing the crack depth leads to high pore water pressure (PWP) and reduces safety. The crack width becomes the door of a channel when rainwater infiltration. The pore water pressure (PWP) was affected if the crack width was large, but if the width was small, the water pressure in the crack was low. Tension cracks affect water pressure conditions and the factor of safety against slope angle. The slope angle experiences significant changes in water pressure and safety factor in the presence of cracks. The combination of crack depth, crack width, and slope angle during rain conditions of intensity and high duration caused a decrease in the safety factor of slope.