The Caquende Hydroelectric Power Plant in Brazil: The AT – Pipe Umbrella System demonstrates its Efficiency and Safety

Near the town of Bonfim in the Federal State of Minas Gerais northwest of Rio de Janeiro, a new 4MW hydroelectric power plant is being built on the Macaúbas River: The PCH Caquende.

Once completed, the power plant will feed approx. 18,500MWh of electricity per year into the power supply system. The PCH Caquende consists of 3 horizontal Francis turbines that are operated at an influx rate of 7m³/s of water. The concrete dam that forms part of the power plant reaches a maximum height of 2.5m and is 60m long.

Within the scope of construction work, a 350m long single tube inlet tunnel is being excavated. Since the tunnel portal is located in an unstable zone, the Type AT – 76 Pipe Umbrella System was used for pre-support.

Due to the self-drilling installation process, the AT – Pipe Umbrella Support System decreases deformations and increases the stability and safety in the working area.

DSI Underground Brasil supplied the complete AT – 76 Pipe Umbrella System on short notice for the construction of the PCH Caquende. The required system components included the AT – Starter Unit with drill bit, AT – Extension Tubes, injection valves in the injection drillings, several AT – Drilling Adapters, the required drill rods and AT – Grouting Caps.

The pipe umbrella tubes were installed piece by piece and overlapped using conventional drill booms with rotary-percussive rock drills. The general contractor was very satisfied with the fast, self-drilling installation of the pipes and their high directional accuracy during installation. Furthermore, DSI Underground Brasil’s specialists supported the jobsite personnel during the professional installation.