The Influence of Built Environment on Landslides. A Case Study: Converney-Taillepied

Abstract

Permanent deep soil landslides are regular downstream movements over a long period. The soil mass moves along an existing sliding surface, contrary to spontaneous landslides that are quite fast downstream movements, starting after a triggering event.

The present study aims to define the effects and the relevant impact that urbanization can cause on the evolution of an important permanent landslide. It reports existing knowledge and describes the phenomenon and its behavior according to increasing urbanization and geotechnical mechanisms.

The intense urbanization (terraces, building reinforcements due to maintenance needs, surface drainage systems, deep drainage boreholes, infrastructure development) has contributed to stabilizing the landslide as a whole. However, geological and hydrogeological factors and the choice of areas where urban density can become higher are equally crucial for landslide stability.

The Converney-Taillepied landslide upon Belmont-Sur-Lausanne, Paudex, and Lutry (Vaud Canton, Switzerland) has been selected as a case study. Several historical events occurred in those areas when they were only rural, while over the past hundred years, the geography has been deeply modified by urbanization.

Once the overall study of the Converney-Taillepied landslides is finished, this work will focus on the most critical areas resulting from the latter. The project analyzes the present conditions of the phenomenon, its characterizations, and the definition of different scenarios to determinate and analyze the different stability factors. Then it proceeds with the analysis of decisive mechanisms that will be able to affect positively or negatively the landslide condition.

Final results suggest that the presence of the built environment on the landslide after the delicate building phase could have a stabilizing effect.