The construction of the Alto Maipo Hydroelectric Power Plant is currently being carried out in the foothills of the Chilean Andes in the Maipo valley, approx. 50 km south-east of Santiago de Chile. In 2012, the Chilean tunnelling division of STRABAG SE was awarded the planning and construction contract for one of the two sections of tunnelling and engineering work for this project by Alto Maipo S.p.A.
Alto Maipo is one of the largest private construction projects in South America. It includes the construction of tunnels and shafts with a total length of 46.5 km that will be excavated using the New Austrian Tunnelling Method as well as tunnel boring machines. The two underground power houses Alfalfal II and Las Lajas in the northern part of the project also form part of this contract. Once completed, the hydropower plant will have an estimated total output of 531 MW.
DSI Chile has been supplying a comprehensive range of ground support products and system since construction work started. In addition to friction stabilizers and forepoling boards, the products also included lattice girders. The lattice girders were custom-tailored and produced at the plant in Santiago de Chile.
At some tunnel portal areas, a pipe umbrella support system was used for pre-support. The system's pipes decrease excavation induced deformations and increase the stability in the working area by transferring loads in the longitudinal direction. In addition, DSI Chile supplied a self-drilling hollow bar system.