Rock Slope Stability Assessment Using Geomechanical Classification and its Application for Specific Slopes along Kodaikkanal-Palani Hill Road, Western Ghats, India

Abstract

Linear infrastructure networks like roads play a vital role in the socio-economic development of hill towns centered on tourism. Stability of the slopes along the hill roads are therefore a major concern and slope failures lead to disruption of traffic and loss of property/life or both. This study analyses the stability of cut-slopes along the Kodaikkanal – Palani hill road in the Western Ghats, India using rock mass classification systems like rock mass rating (RMR), slope mass rating (SMR) and continuous slope mass rating (CSMR). These geomechanical classifications provide a preliminary assessment of rock quality based on rock strength, discontinuity properties, hydrogeological condition of the slopes and slope stability based on the inherent rock strength parameters, discontinuity orientation and method of excavation. The results showed that both rock quality and discontinuity orientation contribute to type of failure in rock slopes with RMR > 40. SMR results are conservative while CSMR classification is matches more closely to the failures obtained from the field survey. CSMR classification represents continuous slope stability conditions and hence are more suitable for development of spatial database. Cutting of roads, thereby, steepening slopes has a definite influence on the stability of slopes.

Demarcation of probable failure zones based on SMR and kinematic analysis

“…Slope mass rating (SMR) developed using basic RMR is a much better tool to study slopes and have been applied worldwide to understand the stability and probability of failure for natural and engineered slopes (Romana 1985;Romana et al 2003;Umrao et al 2011). The SMR method for slope stability analysis has all the basic parameters of RMR as well as it also includes some adjustment factors of the slope-joint interaction and the impact of method of excavation (Sujatha and Thirukumaran 2018). In the present study, RQD has been calculated using Volumetric joint of rock mass (Palmstrom 1974).…”