Stability Analysis and Mitigation Measures for Slope Failure: A Case Study at Lalpani in District Shimla, Himachal Pradesh, India

ABSTRACT Due to unprecedented rainfall in Shimla District of Himachal Pradesh, India several critical slopes were damaged in the rainy season and the sewerage treatment plant located at Lalpani, District Shimla was among one of them. In order to uncover the variables, responsible for the periodic slope collapse, an integrated geotechnical and numerical endeavour is needed service of past stability assessments. Geotechnical investigation reveals relevant soil properties that influence stability. The correlation between rain and slope collapse could be described numerically as an event specific antecedent rainfall threshold. A two‐dimensional LEM (limit equilibrium method) approach to show the slope's stability before and after failure has been employed in present work. The static and dynamic analysis was performed to find the critical failure surface and calculating its Factor of Safety (FOS). The Lalpani slope was significantly stabilised due to the implementation of self‐drilling anchors and RCC retaining walls. The slope first failed without self‐drilling anchors and/or an RCC retaining walls and requested an analysis for the slope with reported Factor of Safety (FOS) < 1. The addition of self‐drilling anchors and RCC retaining walls resulted in and increased FOS = 1.68 for slope‐1 and 1.58 for slope‐2; both having FOS's greater than the commonly accepted critical value of 1.5. Clearly, the proposed stabilising design retained the original slope configuration that would permanently stabilise the slope and allow for sustainability of slope for the foreseeable future and sustainable success for slope safety.