Civil Engineering Reference
In-Depth Information
Figure 20.16
Manual drilling of rock bolts
20.2.6 Advancing support
Spiles
In loose rock, steel spiles are used as advancing support of the working space at the
temporary face in order to limit overbreak and to protect miners against falling rock.
The spiles are arranged in the roof area of the tunnel roughly parallel to the tunnel
axis, forming a spile umbrella that is installed before excavating a round. The length of
the spiles should be at least three times the pullout length in order to enable sufficient
overlap. The spacing between the spiles should not exceed 30 cm. Spiles are carried out
as mortar spiles, driven spiles and injection drill spiles (Wittke et al. 2002).
Mortar spiles with lengths of 3 - 6 m are installed in mortar-filled drillings. They are
designed for rock masses in which the drillings are stable without a casing. Figure 20.17
shows mortar spiles supported by a lattice girder (Fig. 20.10). Manual drilling of mor-
tar spiles is illustrated in Fig. 20.18.
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