Research Information System
ISRM International Symposium - EUROCK 2012, Stockholm, Sweden, 28 - 30 May 2012
© BeFo and ISRM, 2012.Ankara – Istanbul high speed railway construction project consists of 32 tunnels. Tunnel 36 is one of these tunnels and water problem encountered during the excavation of this tunnel is studied in this paper. Total length of that tunnel, which is excavated with NATM, is 4096 meters and located between km 239+934,00 and km: 244+030,80. Tunnel is excavated in Porsuk Miocene Formation (sandstone, clay stone, gravel alternation) and Akpinar Formation (limestone-sandy limestone) which have same ages. Excavations started in the tunnel entrance portal in Porsuk Formation and water inflow has happened while passing Akpınar Formation with dip slip fault at km.241+003,80. Water inflow had negative impact on the units of initial support system and it caused deformations in the lipper-bench especially at the locations where construction hadn’t been finished. Deformations at these locations are occurred in this form; softening of the formations, which carry the footplates, with the effect of water inflow thus, formations couldn’t carry the loads on them and settlements occur. In this study, the problems caused by underground water in the tunnels and solution methods are discussed.