Study on the influence of slope height and angle on the factor of safety and shape of failure of slopes based on strength reduction method of analysis

Abstract

Abstract Background Decreasing slope angle and slope height increases the slope factor of safety and can change the shape of likely slope failure. The increase in the factor of safety is at different rates, which can depend on soil type and slope geometry. Understanding the relationship between the slope height and angle decrease with the increase in factor of safety is vital to implement an efficient method of increasing factor of safety for slope stability problems. In addition, the shape of slope failure has to be observed thoroughly, not to increase the sliding mass of soil for a likely slope failure, even though the factor of safety has increased. Results Three homogeneous slopes of different soil characteristics were analyzed several times by changing the slope height and angle to determine the factor of safety. The shape of failure was also observed and recorded for each slope height and angle decrease. The analysis results indicated that decreasing slope angle increases the factor of safety nearly linearly while a decrease in height increases the factor of safety at a parabolic rate. Slope height decrease increased the factor of safety at a higher rate for the clay soil while slope angle decrease increased factor of safety at a higher rate for sandy soil compared to the other types of soils considered. The toe slide was observed in clayey and sandy clay soils at higher slopes while the base slide was observed at slopes whose height is less than 2 m. The slope slide was dominant on sandy soil at different slope heights and slope angles. Conclusions While the factor of safety of slopes had increased with slope height and angle decrease, the rate of increases and thus the efficiencies are different which depended on the type of soil and geometry of slope. The shape of failure also changed which might increase the sliding mass of soil. This can be risky if slope failure occurs due to unforeseen events. Using the slope height and angle decrease methods for slope stabilization should be thoroughly investigated to choose the most efficient method and also should be checked not to increase the sliding mass of soil for a possible slope failure.