Slope analysis and remedial work on landslide at Taman Setiawangsa, Kuala Lumpur

Abstract

This study investigates the slope failure at Taman Setiawangsa, Kuala Lumpur by using back analysis approach. The catastrophic slope failure was triggered by a rainfall that occurred 2 days before the occurrence of slope failure. Site investigation that includes borehole sampling was conducted to obtain representative information for the study area. The slope can be divided into 3 layers namely Sandy SILT, decomposed of rock and bedrock. Due to the uncertainty about the actual cause of failure initiation, back analyses have been performed via Geostudio 2012 - SLOPE/W and Rocscience - Slide 6.0 for considering various probable mechanisms. In order to deal with the uncertainty and variability of the soil parameters, Limit Equilibrium Method was adopted in this study. Analysis results show that the slope failure is influenced by the shear strength parameter where the cohesion and friction angle at failure were 6 kPa and 33° respectively for a value of FOS is equal to 1.0. For remedial work design of new slope, several options were proposed with comparison on slope stability analyses. Analysis results using SLOPE/W found that the value of FOS obtained for analysis ‘without’ CBP wall is 1.2 and ‘with’ CBP wall is 1.5. In addition, for local stability value of FOS is checked for lower berm of the cut slope is 1.6 and at soil nail’s berm is 2.0. Therefore, this study agreed that the best and recommended design’s option of remedial work is using cut slope with CBP wall with highest FOS value achieved is 1.5.