Oporto Vineyards in Douro River (Portugal)

High length hill stabilization in Douro Vineyard.

Objectives

The main task of this work consist in monitoring the stabilization work performed on a hill in Douro vineyard due to a partial failure of the available retaining structure.

Description

Douro vineyards has a particular relevance since it is world heritage. In this context, any intervention must be done with minimal impact but still fulfilling all safety requirements.

Following an incident near route EN222 (between Régua and Gagáuste dam) in which a partial failure occurred in a retaining wall structure build in shale masonry and instability situations were detected in nearby hills due to high precipitation, a stabilization project able to overcome this hazard situation was required.

The work consisted on a closely surveillance of the entire stabilization work, over several fields, namely: testing interpretation, definition of geotechnical parameters, numerical model definition, creation of a geotechnical solution, selection of constructive methods and definition of monitoring systems.

The recommended solution required the construction of an efficient drainage system alongside the entire hill, in order to control soil moisture content and assure soil’s shear strength. Also, at slope base and to protect the route, a gabion retaining wall was performed and reinforced with a piled wall.

Results

This work allowed the development, as pretended, of a minimalistic stabilization project that respect the framework and landscape-heritage value, and also the safety levels required in modern geotechnical design..