Engineering Rock Mechanics

18 Geological setting

Figure 2.5 Construction of the underground facilities at the Alto Lindoso hydro-electric
project in Portugal.

structure needs to be stabilized by engineered reinforcement or sup-
port.
In Fig. 2.6, the desert location of a potential repository for high-level
radioactive waste is shown. Here, the purpose is waste isolation for
long periods and there are many aspects of geology, hydrogeology
engineering and biospherics to consider. Again, it is the features of the
rock mass resulting from its geological history that dominate the design,
e.g. the presence of rock fractures, the permeability of the fracture array,
and the age of the water currently in the rock mass.
The rock engineering projects that have been described are widely
different in their locations and purposes but, whatever the purpose of
the project, the rock mass is the host structure. Unlike other materials

Figure 2.6 View southwest towards Death Valley from the top of Yucca Mountain in

Nevada, USA, the site of a potential radioactive waste repository in a dry region. Note

Amargosa Desert to the left of the picture, and the volcanic craters in Crater Flats at the

middle right.