Effect of applied load on the stability of unreinforced and reinforced slopes

Abstract

Recent development in hilly area has highlighted issues related to instability in engineered as well as natural slopes, hence; it is a challenge to both professionals and researches in Malaysia to address the problem related to landslides and slope failures. Several occurrences during the past few years include Highland Tower collapse in December 1993, Bungalow collapse at Taman Hillview in November 2002, the massive landslide occurred at Bukit Antarabangsa in December 2008, and the recent landslide at Hulu Langat in May 2011. Therefore, uncontrolled development which place structural foundation too near to the slope crest on hilly area may lead to slope failure. Thus, it is essential to consider the safe distance between the foundation and the slope crest. The aim of this study is to determine the safe distance of foundation on slope crest using a commercial software Slope/W (Geostudio, 2007). Morgenstern-Price and bishop method are selected for slope stability analysis due to the flexibility in selecting the critical slip surface. A case study at PT 4697, Seksyen7, Shah Alam, Selangor was selected for the analysis. Applied loading of 10kPa, 15kPa, 20kPa, 30kPa and 50kPa will be placed at various distances from the crest of the slope. The result from the slope stability analysis had indicated that the construction of reinforced earth wall improved the stability of slope but the loading on slope crest decreases the factor of safety of both unreinforced slope and reinforced slope. Therefore the load within unstable area will results in the depressions at the point of applied load, however once the load is moved beyond the unstable area, its effect become significantly minimized and the pattern of safety factor is constant start from a stable distance where the increasing of loading will remain constant for the factor of safety.