In the Nordic countries, different praxis concerning applied grout pressure has developed.
In Norway, very high pressures are used while considerably lower is used in Sweden.
Any research that shows which pressure that is suitable to use, and the consequences if
an incorrect pressure is used, has not been performed in Norway or Sweden. However,
knowing which grout pressure that is optimal to obtain an acceptable sealing of the rock
mass is essential for cost efficient grouting.
In this work, two different grouting projects have been analysed, a Norwegian where a
high grout pressure was used and a Swedish where lower pressure was used. Both projects
have been analysed with the theory for the Real Time Grouting Control Method together
with the new theories that has been developed at KTH for jacking of rock fractures due
to the grouting pressure. Based on the results from these analyses, advantages and
disadvantages with high and low pressures respectively are discussed and conclusions
presented. The idea is that this work could be used as a basis for future research
concerning the work on suitable grout pressure.
The work has been performed by Jalaleddin Rafi together with Håkan Stille and Fredrik
Johansson at the Division of Soil and Rock Mechanics, KTH. The analyses of the Holm-
Nykirke project has partly been performed by Simon Nikolaev as a part of his master
thesis project at KTH.
A reference group has followed the work and contributed with valuable contributions and
review comments. The group consisted of Thomas Dalmalm (Swedish Transport Administration),
Björn Stille (Sweco), Mats Holmberg (Tunnel Engineering), Johan Funehag
(Chalmers), Lars Hässler (Golder), Eivind Gröv (Sintef &NTNU) and Per Tengborg
(BeFo).
The project was funded by the Rock Engineering Research Foundation – BeFo.
Stockholm, May 2017
Per Tengborg
Jacking of rock fractures during pre-grouting in Scandinavian tunneling projects – a study of the effects from chosen grouting pressure
Författare:
Jalaleddin Yaghoobi Rafi, Håkan Stille, Fredrik Johansson
Rapportkategori:
BeFo-rapport
Rapportnummer:
156
Utgivningsår:
2016
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