RD&D-Programme 2004 - SKB

Programme
SKB keeps track of current research and development in the field of rock construction and
civil engineering to keep its know-how and knowledge in the field up-to-date.
In the autumn of 2003, SKB started an investigation aimed at clarifying which methods
and technologies are available for creating various chambers in the rock i.e. ramp, shaft,
central area, main tunnels, deposition tunnels and deposition holes. For the deposition tunnels
in particular, it is important that rock damage be limited. In the project, which is expected to
last until 2007, in addition to an inventory of available methods and technologies, assessments
will be made of possible development of drill-and-blast techniques and mechanical excavation
up until the time when rock extraction in the deep repository is to be done. The project will be
carried out in two stages where the first stage, which will be concluded in 2004, will serve as
a basis for the preliminary choice of methods and technologies for rock extraction presented in
Layout D1 for the deep repository. The second stage in the project, which will be concluded in
2007, will comprise the final choice of methods and technologies on which Layout D2 will be
based.
Possible methods for rock excavation and which methods should be studied further have been
specified for different type of openings, see Table 10-1. Preliminary reference methods in
Layout D1 have been marked in the table. Among the alternatives chosen for further studies are
e.g. conventional drill-and-blast, TBM boring and reaming. Controlled blasting will limit the
damaged zone created around excavated rock chambers. Boring of horizontal demonstration
drifts at the Äspö HRL is planned to be done during 2004.
Different studies for follow-up of the blast-damaged zone are planned, for example by slot
sawing in the Aspe tunnel at the Äspö HRL or other verifying tests. Studies and inspection
of the blast-damaged zone in connection with drilling and controlled blasting of the ramp in
Onkalo in Finland are being discussed with Posiva.
Table 10-1. Possible methods for rock extraction of the different openings in the deep repository.
Type of openings Possible methods Methods that will be studied further
in deep repository
Ramp Drill-and-blast Controlled blasting 1
TBM (tunnel boring machine) TBM
Skip shaft (blind) Drill-and-blast Controlled blasting with work platform
SBM (shaft boring machine) and drilling equipment in sunk shaft 1
Ventilation and RBM (full-face boring of Back reaming 1
elevator shaft
shaft by raise boring)
Central area and Drill-and-blast Controlled blasting 1
other rock caverns
Mechanical milling
Main tunnel Drill-and-blast Controlled blasting 1
Mechanical milling
TBM
TBM
Deposition tunnels, Drill-and-blast Controlled blasting 1
KBS-3V Back reaming TBM (with improved design)
Mechanical milling
Back reaming with service tunnel
TBM
Deposition holes SBM SBM 1
Down reaming
Down reaming
KBS-3H, horizontal Water hammers in cluster Water hammers in cluster formation
deposition holes Small TBM Down reaming without service tunnel
Back reaming
Down reaming with service tunnel
Back reaming with service
tunnel
1
Preliminary reference method in Layout D1.
116 RD&D-Programme 2004