O. Aydan et al., THE SQUEEZING POTENTIAL OF ROCK AROUND TUNNELS - THEORY AND PREDICTION WITH EXAMPLES TAKEN FROM JAPAN, Rock mechanics and rock engineering, 29(3), 1996, pp. 125-143
Large deformations of surrounding media around tunnels are often encou
ntered during excavations in rocks with squeezing characteristics. The
se deformations may sometimes continue for a long period of time. Pred
ictions of deformations of tunnels in such grounds are urgently needed
, not because of stability concerns, but also of their sevicability. I
n the present study, the squeezing phenomenon of rock around tunnels a
nd its mechanism and associated factors are first clarified by careful
ly studying failures of tunnels, and a survey of tunnels in squeezing
rocks in Japan is presented, and its results are summarised. Then, a p
ractical method is proposed to predict the squeezing potential and def
ormation of tunnels in squeezing rock and this method has been applied
to actual tunnelling projects, where squeezing problems were encounte
red, to check its applicability and validity. Finally, an extension of
this method to the time-dependent behaviour of squeezing rocks is giv
en and an application of this method to an actual tunnel is presented.