Environmental Engineering Reference
In-Depth Information
2
GeoMeTRY anD Technical
chaRacTeRisTics
2.1
List of tunnels
The interest that reaches this high number of tun-
nels have been built on the island, is strengthened
by the diversity of geological materials, volcanic
and sedimentary, they have crossed.
This information is invaluable for future tunnel
projects that will executed.
The aim of this paper is to show an inventory of
tunnels built till this day, the design features used and
the geotechnical properties of the materials traversed.
as an example we have taken three real examples
of tunnels implemented on different lithologies of
volcanic origin.
as a summary of tunnels implemented so far
today in Grand canary, it shows a tables of those
in which shows the basic design data and descrip-
tive projects.
Figure 2.
los siete lajares tunnels.
deposit of phonolite lava flows with volcanic
agglomerates in the base.
The constructive method used was new austrian
tunneling method, initiated by a particular stage
of development and of smashes another basically
doing a shotcrete support and bolts.
Were used from the outset two jumbo robots
that allowed to drill a whole section.
among the major geotechnical problems
detected mainly highlights from the column
stratification phonolite producing many flat roofs,
(
Fig. 3
).
The correction used was rock reinforcement
through the use of reinforced shotcrete in structural
interaction with rock bolts of steel-fibre-reinforced
shotcrete and Bernold type sheet system.
3
GeoloGical anD GeoTechnical
seTTinGs
3.1
General geology
Geological variability traversed by tunnels imple-
mented is very diverse, from pyroclastic or
ignimbrites with basanite to phonolitic composi-
tion, trachytic and rhyolitic ignimbrite lava flows.
some sedimentary materials have been presents.
4
GeoMeTRY anD Technical
chaRacTeRisTics
4.4
Phonolitic, trachytic, rhyolitic ignimbrites
and lava flows
The stretch arguineguín-Puerto Rico is a site of
four twin tunnels bi-tube type unidirectional and
one bidirectional, that in just two miles away is a
point of reference for the entire island. The geol-
ogy traversed is diverse, with a variety of materials
Phonolitic composition and sedimentary deposits
as conglomerates and slope deposits.
The twin tunnels ingeniero heriberto linares,
with up to 1188 meters in mine on the land side.
explosives are used to dig through entire sec-
tion. The reinforcement was performed with shot-
crete and rock bolts, except for some short stretches
where use trusses. For sizing was used the active
structural Design, which uses the classification of
Bieniawsky (1979) to estimate the properties of
rock mass by laboratory tests and thus holds by
calculating the stress-strain.
The tunnels entrances were performed with
slopes. The inclination was 1(h):2(V).
4.1
Geology examples
Below are three examples of projects put in prac-
tice according to the geology in the project area.
4.2
Basanite pyroclasts and lava flows
located in the Tafira ring road (Gc-4), the double
false tunnel los siete lagares is around pyroclastic
deposits and basanite lava flows of very dark shades.
The constructive method was executed by exe-
cution of the trench and subsequent execution of
the tunnel structure through where stirrup rests
triarticulated arch formed by prefabricated plates.
its length is 225 meters in two entrances, featuring
4.3
Phonolite lava flow and agglomerates
situated just off the la laja beach (Gc-1), the
tunnel named adolfo cañas crosses a powerful
