Geotechnical investigation guide for building in volcanic environments - Volcanic Rock Mechanics - page 231

Geotechnical investigation guide for building in volcanic
environments

l.e. hernández
Regional Ministry of Works, Government of the Canary Islands, Spain

J.a. Rodríguez-losada
Department of Soil Science and Geology, University of La Laguna, Tenerife, Spain

c. olalla
E.T.S.I.C.C.P., Universidad Politécnica de Madrid, Spain

J. Garrido-Manrique
Department of Civil Engineering, Universidad de Granada, Spain

aBsTRacT: The recent emergence of the spanish Building Technical code set a regulatory landscape
where geotechnical studies become mandatory for construction in spain. This code provides a classifica-
tion for building and terrain types, depending on which performs the geotechnical research planning. it is
therefore necessary to identify and classify the terrain as one of the three types defined in the code. The
Government of the canary islands has developed a guide that will allow code enforcement to volcanic
terrains of the canary islands. in this paper, the geotechnical units of the canaries as well as their clas-
sification according to the code are defined. in addition, the number and type of minimum geotechnical
surveys carried out in each geotechnical unit is specified as a function of the planned building. since
the canary islands consist of a wide range of volcanic products, this guide can be applied to any other
volcanic region.

1 inTRoDUcTion canaries terrains of volcanic origin are very different

to the spanish mainland, so that implementation of the
cTe in the islands has had some difficulties.
in the past decade canarian government has
done several studies about geomechanical proper-
ties of volcanic materials. Results has created the
first database with geomechanical and geochemi-
cal properties, and correlations between various
parameters studied, which have been published and
accepted by the scientific community (Rodriguez-
losada et al., 2006, 2007, hernandez-Gutierrez
et al., 2007). in addition, the government has devel-
oped geotechnical mapping of the canary islands.

The canary islands are located in the atlantic
ocean, close to the northwest coast of africa,
in front of Western sahara and Morocco. all of
islands are volcanic in origin and form the Maca-
ronesia ecoregion with the azores, Madeira, cape
Verde and the savage isles.
canary island's territory covers an area of
7.447 km 2 and populations reached 2 million peo-
ple in 2009. The economy is based primarily on
tourism, but in recent decades, due to tourism
development and population growth, the construc-
tion sector has been very important in the economy
of the islands.
Due the increasing demand for quality in the
buildings by the society, the Government of spain
recently published the spanish Building Technical
code, “código Técnico de la edificación” (cTe,
2006). This code creates a situation where the
geotechnical studies for building are needed and
prescriptive.
according to the cTe, geotechnical surveys will
be carried out depending on the type of building
( Table 1 ) and the type of terrain ( Table 2 ).

Table 1. Type of building according to the cTe.

Type of building Description

c-0 Buildings of less than 4 levels and

built area less than 300 m 2

c-1 other buildings of less than 4 levels

c-2 Buildings from 4 to 10 levels

c-3 Buildings from 11 to 20 levels

c-4 Monumental, unique, or more

than 20 levels