Squeezing ground in tunnelling is associated with considerable deformations of the tunnel perimeter and faces. These phenomena are accompanied by the corresponding deformation and very often the destruction of the tunnel support. Therefore, it is required for the client, designer and contractor to reduce or overcome the difficulties associated with squeezing ground by using suitable countermeasures. Heavily squeezing conditions were encountered during construction of the Nikkureyama Tunnel, Japan. The maximum crown settlement and convergence in the mudstone section (length approximately 380m) of the tunnel were 3,120 mmand 2,997 mm, respectively. The damage and destruction of support members were also observed occasionally. This paper summarizes the failure phenomena and countermeasures for tunnelling under such difficult conditions.
Squeezing ground …
AUTORI: Nakamura Y., Hada M., Sakai H., Miyagawa Y., Kawakami E., Nagai T. RIG ANNO: 1999 NUMERO: 1 Numero di pagina: 89