Development of a landslide hazard analysis program for a 41-km railway line across "Serra do Mar" range, Brazil

Landslides are a major cause of losses and damages in railways and roadways which cross hilly regions. Some landslides may cause traffic interruption for several days, leading to severe prejudice to cargo flow in busy transportation systems. Landslide studies are essential to identify potentially unstable areas, and their consequent impact on infrastructure, and prioritize critical areas to implement failure prevention measures. This paper presents the results of a Landslide Hazard Analysis Program (LHAP) developed to evaluate failure-prone slopes along a 41-km rail that crosses the "Serra do Mar" mountain range, located in the southeastern region of Brazil. This railway was built in the late 1920s and is still vital to transport commodities from the Brazilian countryside to the major port in Brazil, located in the city of Santos. The paper shows how local geological-geotechnical conditions, associated with construction peculiarities, resulted in a very fragile infrastructure. Recent failures caused severe losses and damages to the railway system, leading to traffic interruption for several days and prejudice to cargo flow. The Landslide Hazard Analysis Program was developed to identify and understand the main causes of slope failures and prioritize intervention with basis on failure susceptibility and consequences to the railway. A failure prevention program was developed with basis on the results and consisted in stabilizing slopes with both temporary and permanent retaining structures as well as restoring and implementing a new drainage system. The methodology presented in this paper could be validated with basis on data from five slope failures that occurred in cut slopes after the ranking had been defined, demonstrating the suitability of the analysis. With some adaptations, the methodology may be used in similar linear structures such as roadways, pipelines, and others.