The investigation and design for a unique architectural space – The Chillida Cavern, Mount Tindaya, Fuerteventura

The late Spanish artist, Eduardo Chillida, proposed the creation of a large subterranean sculpture within Tindaya Mountain, on the island of Fuerteventura, Canary Islands. The sculpture consists of a 15 m span entrance tunnel to a cavern (65 m long, 49 m wide and 45 m high) and two rectangular light shafts (20 m × 20 m and 21 m × 30 m). The two light shafts are orientated to capture the rotation of the sun and moon as they cross the mountain and provide the only light in the cavern. The entrance tunnel would provide a view to the sea and western sky from within the cavern.The sculpture would have a flat roof and slightly inclined walls. The excavated surfaces are to be formed with flat, high quality finishes, with no visible support. This results in a unique engineering challenge, whose construction would push the limits of cavern design and construction.In order to realise the artist’s concept, the design comprises the formation of a series of reinforced rock arches within the rock mass above the cavern roof and pre-support of the cavern roof with rock anchors fixed to the arches. The arches would be created with rock anchors radiating around the tunnels which would also provide access for long term maintenance, monitoring instrumentation and drainage. The reinforced rock arch tunnels would be formed from the light shafts prior to the main cavern excavation. The rock anchors supporting the cavern roof would be installed in predrilled holes as they are exposed during cavern excavation.The cavern would be constructed within the trachyte rock mass making up the majority of the mountain and would also encounter highly persistent master joints and basalt dykes. Specific local treatment and support is expected to be required to stabilise these features. There are also durability issues associated with the particular micro-structure and porosity characteristics of the predominant trachyte rock itself that have been addressed to meet the long-term design requirements.This paper describes the phased investigation and development of the design concept. The project is currently under consideration by the Canary Islands Government.

► Eduardo Chillida’s subterranean sculpture in Tindaya Mountain, Fuerteventura.
► Cavern to have a flat roof and high quality finished surfaces, no visible support.
► Design comprises curved reinforced rock arch tunnels and tensioned rock anchors.
► Cavern in non-durable trachyte with persistent master joints and basalt dykes.
► The project is under consideration by the Canary Islands Government.