Geosintéticos | TDM

1. The Problem
In recent years, the Chosica district in Lima has been affected by mudslides that occur in its streams. In 2015 alone, nine deaths were reported, 341 families were affected, and 70% of the district’s water service and 80% of its sewage systems were affected. Faced with the imminent threat of these events due to the proximity of the El Niño phenomenon, the National Water Authority (ANA) worked together with the TDM Technical Department to achieve a comprehensive solution and reduce the population’s vulnerability to mudslides in nine priority streams in the area (El Pedregal, Castilla, Huampani, Quirio, La Libertad, Rayos de Sol, La Ronda, Santo Domingo, and Carossio). The short execution time and the harsh geographical conditions were determining and essential factors to consider in the project, due to the proximity of the rains.

2. The Solution

The facility’s conditions and similar experiences around the world were key factors in the project’s development. The system implemented consisted of the installation of 22 Dynamic Debris Flow Barriers in nine streams in the Chosica District. These barriers provide improved functionality, retention capacity, and resilience compared to traditional concrete and masonry wall structures. It is important to highlight that this project is the largest landslide control project in Latin America, which included dynamic barriers with heights of 4.00 and 6.00 meters, with channel lengths of up to 60.00 meters. The assembly of the 22 structures and preliminary works were completed in record time, within the timeframes required to complete engineering simultaneously with construction (a fast-track project), thanks to the excellent integration of the TDM Group’s Engineering, Technical Department, Logistics, and Construction departments.

3. Benefits

A dynamic debris flow barrier is a system of components defined by the manufacturer, capable of retaining a specific amount of material caused by dynamic impacts from mixed/granular debris flows or mud flows. The calibration of the model and the strength of each of its components are verified in field tests involving impacts from naturally generated debris flows in Switzerland (Illgraben Gorge), under the supervision and approval of the WSL Swiss Federal Research Institute. Unlike conventional rigid concrete or masonry walls, dynamic debris flow barriers are flexible systems, comprised of networks of circular rings that absorb impact energy, which is transmitted to the channel’s perimeter anchors. The multi-level concept allows us to propose more than one structure along the riverbed, as was done in the Quebradas de Chosica, in order to gradually dissipate energy and mitigate the phenomenon of mudslides in the affected areas.